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5 pages, 3726 KiB  
Interesting Images
Cytomegalovirus Enterocolitis in a Patient Treated with Methylprednisolone for Amiodarone Hypersensitivity Pneumonitis
by Darinka Purg, Marko Hojnik and Nika Aleksandra Kravos Tramšek
Diagnostics 2024, 14(23), 2633; https://doi.org/10.3390/diagnostics14232633 - 22 Nov 2024
Abstract
Cytomegalovirus (CMV) is a common cause of infection in immunocompromised individuals, such as patients with hematological malignancies or AIDS, but can also occur in patients with other acquired immunodeficiencies. In tissue-invasive diseases, CMV diagnosis requires CMV DNA in the plasma and the histological [...] Read more.
Cytomegalovirus (CMV) is a common cause of infection in immunocompromised individuals, such as patients with hematological malignancies or AIDS, but can also occur in patients with other acquired immunodeficiencies. In tissue-invasive diseases, CMV diagnosis requires CMV DNA in the plasma and the histological confirmation of CMV in a tissue or organ. Evidence of CMV colitis requires a characteristic endoscopic picture with ulcers with a well-defined, convex appearance and CMV viral inclusions in the form of an “owl’s eye” on mucosal sections stained with hematoxylin and eosin. CMV-specific immunohistochemistry is the gold standard for identifying CMV in tissue biopsies. It is important to consider a CMV infection in the diagnostic process, as it may delay the diagnosis and the treatment. We present the case of a 78-year-old patient with amiodarone interstitial lung disease who was treated with methylprednisolone. Two weeks after the start of his treatment, he was admitted to the hospital for acute gastroenterocolitis and Addisonian crisis. An examination had confirmed a tissue-invasive CMV disease. He was treated with valganciclovir for a total of six weeks. After the completion of treatment, the patient showed no clinical signs of CMV infection, and both laboratory and histological examinations revealed no residual CMV disease. Tissue-invasive CMV disease can occur in patients with acquired immunodeficiency, which may result from various causes, including glucocorticoid treatment. Full article
(This article belongs to the Section Diagnostic Microbiology and Infectious Disease)
Show Figures

Figure 1

Figure 1
<p>(<b>A</b>–<b>D</b>): Hematoxylin and eosin staining (<b>A</b>,<b>B</b>) and immunohistochemical CMV staining (<b>C</b>,<b>D</b>) of the patient’s tissue samples from terminal ileum. Severe tissue-invasive CMV disease of the gastrointestinal tract and even disseminated CMV disease can occur in immunocompromised patients. Gastrointestinal infections remain a common cause of mortality in these patients [<a href="#B1-diagnostics-14-02633" class="html-bibr">1</a>]. The typical histological findings of CMV infection are the presence of intranuclear “owl’s eye” inclusions in the endothelial and mesenchymal cells, thickened nuclear membrane, coarse red intracytoplasmic granules, increased apoptotic bodies, an inflammatory infiltrate (mixed inflammatory plasma cell rich infiltrate) in mucosa, often accompanied with an area of necrosis and ulcerations [<a href="#B2-diagnostics-14-02633" class="html-bibr">2</a>]. We present a 78-year-old Caucasian male patient, with a history of nonischemic dilatative cardiomyopathy with reduced left ventricular ejection fraction (20%), asthma, and type 2 diabetes mellitus. He had no previously known gastrointestinal medical conditions, except for having undergone surgery for an inguinal hernia as a young adult. A cardiologist introduced amiodarone treatment for the past four years to prevent another episode of atrial fibrillation. He has also been receiving furosemide, bisoprolol, acetylsalicylic acid, rosuvastatin, and a combination of inhalation therapy (formoterol, beclomethasone, and glycopyrronium bromide). In the last three years, his chronic conditions had been well managed, and he had not required hospitalization until recently. Three weeks prior to the diagnosis of the CMV infection, he was hospitalized due to worsening community-acquired bacterial pneumonia with increasing respiratory insufficiency. However, a high-resolution computed tomography (HRCT) of the chest showed typical changes related to amiodarone-induced interstitial pneumonitis. Bronchoscopy and biopsy were not considered due to comorbidities and the typical HRCT findings. Amiodarone was discontinued, and the methylprednisolone therapy was initiated at a dose of 0.5 mg/kg body weight and pantoprazole 40 mg OD during the whole time of methylprednisolone treatment. After 14 days of treatment with methylprednisolone, both diarrhea and vomiting occurred. He defecated up to 10 times per day but had no fever. On day 18, he was admitted to the hospital due to hypotension and tachycardia, which were recognized as an Addisonian crisis with etiologically nonspecific diarrhea. Laboratory findings included a mild normocytic anemia, a mild hypokalemia, transient deterioration of renal function, elevated C-reactive protein, decreased levels of total calcium, vitamin D, and fibrinogen, hypoalbuminemia, and a rise in INR without anticoagulation therapy. Microbiological specimens were collected, and ceftriaxone was empirically administered. Our patient required hydrocortisone replacement therapy. A buccal swab confirmed Herpes simplex virus type 1 gingivostomatitis and a positive serum CMV DNA level (372 IU/mL). Valacyclovir was started orally to treat stomatitis for a period of five days. Due to the positive CMV DNA and persistence of diarrhea, further diagnostics were performed. On an abdominal CT scan, we found signs of infectious enteritis (<a href="#diagnostics-14-02633-f002" class="html-fig">Figure 2</a>A,B). An upper gastrointestinal endoscopy confirmed esophageal candidiasis and altered duodenal mucosa. Histology showed mild to moderate Helicobacter pylori chronic gastritis without glandular atrophy, intestinal metaplasia or intraepithelial neoplasia, and mild chronic duodenitis. No histopathological changes were suggestive of the chronic inflammatory bowel disease, coeliac disease, parasitic infection, Whipple’s disease or <span class="html-italic">Giardia</span> spp. Inflammatory lesions with multiple ulcers in the terminal ileum and a rectal ulcer were seen on colonoscopy with terminal ileoscopy. Histology confirmed the presence of CMV in the terminal ileum (<b>A</b>–<b>D</b>) and in the random samples of the colonic mucosa. We repeated serum CMV DNA. The viral load was high (44,900 IU/mL), along with the presence of CMV specific IgG and IgM. We confirmed the presence of tissue-invasive CMV disease in an immunocompromised patient. He was treated with valganciclovir at a dose of 900 mg BID orally. After seven days of treatment, a decline in viral load (serum CMV DNA 2380 IU/mL) was observed. We continued treatment on an outpatient basis as the clinical condition improved with relief of the intestinal syndrome. All other comorbidities were in a stable phase, and we continued methylprednisolone therapy at a low dose (4 mg daily). The CMV DNA was regularly checked and, according to the results, valganciclovir therapy was discontinued after six weeks. Follow–up endoscopy examinations and histological mucosal samples showed no signs of CMV disease. This Figure shows small intestinal mucosa biopsy samples in the patient with CMV infection. The villi were normally dense with epithelium without atypia. The lamina propria was focally mildly fibrosed, moderately infiltrated with mononuclear cell inflammatory infiltrate rich with plasma cells ((<b>B</b>)—area with symbol *). A few eosinophilic and neutrophilic granulocytes were also present in the inflammatory infiltrate. Lymphatic aggregates were present. There were no signs of cryptitis, no crypt microabscesses and no epithelioid granulomas. Immunohistochemical staining revealed nuclear staining in CMV infected cells ((<b>C</b>,<b>D</b>)—marked with arrows). Paraffin-embedded tissue blocks were sectioned with a microtome to obtain 3–5 μm-thick paraffin sections and were placed onto a glass slide (StarFrost; Knittel, Braunschweig, Germany). Hematoxylin and eosin staining was performed on a fully automated VENTANA HE 600 system according to standard protocol. Immunohistochemical staining was performed for the visualization and localization of CMV specific antigens on formalin-fixed, paraffin-embedded tissue samples from terminal ileum. Paraffin-embedded tissue blocks were sectioned with a microtome to obtain 3–5 μm-thick paraffin sections, which were placed onto a glass slide (Superfrost Plus; Epredia, Portsmouth, UK). The tissue slides were dehydrated in a slide-drying ventilation oven for 60 min at 60 °C. IHC staining was carried out on an automated system (BenchMark Ultra; Roche Tissue Diagnostics’, Mannheim, Germany) using detection kits (UltraView Universal DAB detection kit; Roche Tissue Diagnostics’, Mannheim, Germany; cat. no. 05269806001) following the manufacturer’s instructions. A deparaffinization solution (EZPrep solution; Roche Tissue Diagnostics’, Mannheim, Germany; cat. no. 05279771001) was used for 4 min at 72 °C for the complete dissolution of the paraffin. Protease (Protease 1; Roche Tissue Diagnostics’, Mannheim, Germany; cat. no 05266688001) was used for the epitope retrieval for 8 min. The slides were applied and incubated with the primary antibodies anti-CMV (Sigma-Aldrich; Cell Marque, Rocklin, CA, USA; cat. no. 213M-16-RUO, lot: 0000285872) for 24 min at 36 °C (optimized dilution 1:100 in an antibody diluent (Ventana; Roche Tissue Diagnostics’, Mannheim, Germany; cat. no. 05261899001)). The specific anti-CMV antibody was located by a specific secondary antibody to which an enzyme-HRP labelled tertiary antibody was bound. The complex was then visualized with hydrogen peroxide substrate and 3,3′-diaminobenzidine tetrahydrochloride (DAB) chromogen, which produces a brown precipitate that was visible by light microscopy. CMV infection may manifest as the CMV syndrome (fever, malaise, myalgia, etc.) or as tissue-invasive CMV disease. It can affect the gastrointestinal tract from the oral cavity to the anus [<a href="#B3-diagnostics-14-02633" class="html-bibr">3</a>,<a href="#B4-diagnostics-14-02633" class="html-bibr">4</a>]. Detecting the CMV-specific IgM and IgG antibodies demonstrates a primary CMV infection. In immunocompromised patients with clinical signs, the diagnosis of CMV disease requires the presence of CMV DNA in the plasma and histological confirmation of CMV in a tissue or an organ [<a href="#B5-diagnostics-14-02633" class="html-bibr">5</a>]. CMV-specific immunohistochemistry (IHR) is the gold standard for identifying CMV in tissue biopsies [<a href="#B6-diagnostics-14-02633" class="html-bibr">6</a>]. The data showed that CMV infection was detected more frequently if the referring physician requested an IHR for the CMV when the patient was immunocompromised due to either underlying disease or immunosuppressive drugs, if more biopsy specimens were obtained, or if the specimens showed severe inflammation [<a href="#B7-diagnostics-14-02633" class="html-bibr">7</a>,<a href="#B8-diagnostics-14-02633" class="html-bibr">8</a>]. At our center, immunohistochemical staining for CMV is performed either at the clinician’s request for immunocompromised patients or at the pathologist’s request due to microscopic features on biopsy, including the degree and type of inflammation and viral cytopathic effects. The most common manifestation of invasive CMV disease is gastrointestinal involvement. Evidence of CMV colitis requires a characteristic endoscopic picture with ulcers with a well-defined, convex appearance and CMV viral inclusions in the form of an “owl’s eye” on mucosal sections stained with hematoxylin and eosin [<a href="#B4-diagnostics-14-02633" class="html-bibr">4</a>]. Treatment can be challenging as viremia may be low or even absent despite a marked clinical picture of gastrointestinal involvement. Relapses can also be expected; therefore, prolonging antiviral therapy beyond the point at which no CMV DNA is detected in the plasma, is reasonable for optimal treatment. The decision regarding secondary prophylaxis varies [<a href="#B9-diagnostics-14-02633" class="html-bibr">9</a>].</p>
Full article ">Figure 1 Cont.
<p>(<b>A</b>–<b>D</b>): Hematoxylin and eosin staining (<b>A</b>,<b>B</b>) and immunohistochemical CMV staining (<b>C</b>,<b>D</b>) of the patient’s tissue samples from terminal ileum. Severe tissue-invasive CMV disease of the gastrointestinal tract and even disseminated CMV disease can occur in immunocompromised patients. Gastrointestinal infections remain a common cause of mortality in these patients [<a href="#B1-diagnostics-14-02633" class="html-bibr">1</a>]. The typical histological findings of CMV infection are the presence of intranuclear “owl’s eye” inclusions in the endothelial and mesenchymal cells, thickened nuclear membrane, coarse red intracytoplasmic granules, increased apoptotic bodies, an inflammatory infiltrate (mixed inflammatory plasma cell rich infiltrate) in mucosa, often accompanied with an area of necrosis and ulcerations [<a href="#B2-diagnostics-14-02633" class="html-bibr">2</a>]. We present a 78-year-old Caucasian male patient, with a history of nonischemic dilatative cardiomyopathy with reduced left ventricular ejection fraction (20%), asthma, and type 2 diabetes mellitus. He had no previously known gastrointestinal medical conditions, except for having undergone surgery for an inguinal hernia as a young adult. A cardiologist introduced amiodarone treatment for the past four years to prevent another episode of atrial fibrillation. He has also been receiving furosemide, bisoprolol, acetylsalicylic acid, rosuvastatin, and a combination of inhalation therapy (formoterol, beclomethasone, and glycopyrronium bromide). In the last three years, his chronic conditions had been well managed, and he had not required hospitalization until recently. Three weeks prior to the diagnosis of the CMV infection, he was hospitalized due to worsening community-acquired bacterial pneumonia with increasing respiratory insufficiency. However, a high-resolution computed tomography (HRCT) of the chest showed typical changes related to amiodarone-induced interstitial pneumonitis. Bronchoscopy and biopsy were not considered due to comorbidities and the typical HRCT findings. Amiodarone was discontinued, and the methylprednisolone therapy was initiated at a dose of 0.5 mg/kg body weight and pantoprazole 40 mg OD during the whole time of methylprednisolone treatment. After 14 days of treatment with methylprednisolone, both diarrhea and vomiting occurred. He defecated up to 10 times per day but had no fever. On day 18, he was admitted to the hospital due to hypotension and tachycardia, which were recognized as an Addisonian crisis with etiologically nonspecific diarrhea. Laboratory findings included a mild normocytic anemia, a mild hypokalemia, transient deterioration of renal function, elevated C-reactive protein, decreased levels of total calcium, vitamin D, and fibrinogen, hypoalbuminemia, and a rise in INR without anticoagulation therapy. Microbiological specimens were collected, and ceftriaxone was empirically administered. Our patient required hydrocortisone replacement therapy. A buccal swab confirmed Herpes simplex virus type 1 gingivostomatitis and a positive serum CMV DNA level (372 IU/mL). Valacyclovir was started orally to treat stomatitis for a period of five days. Due to the positive CMV DNA and persistence of diarrhea, further diagnostics were performed. On an abdominal CT scan, we found signs of infectious enteritis (<a href="#diagnostics-14-02633-f002" class="html-fig">Figure 2</a>A,B). An upper gastrointestinal endoscopy confirmed esophageal candidiasis and altered duodenal mucosa. Histology showed mild to moderate Helicobacter pylori chronic gastritis without glandular atrophy, intestinal metaplasia or intraepithelial neoplasia, and mild chronic duodenitis. No histopathological changes were suggestive of the chronic inflammatory bowel disease, coeliac disease, parasitic infection, Whipple’s disease or <span class="html-italic">Giardia</span> spp. Inflammatory lesions with multiple ulcers in the terminal ileum and a rectal ulcer were seen on colonoscopy with terminal ileoscopy. Histology confirmed the presence of CMV in the terminal ileum (<b>A</b>–<b>D</b>) and in the random samples of the colonic mucosa. We repeated serum CMV DNA. The viral load was high (44,900 IU/mL), along with the presence of CMV specific IgG and IgM. We confirmed the presence of tissue-invasive CMV disease in an immunocompromised patient. He was treated with valganciclovir at a dose of 900 mg BID orally. After seven days of treatment, a decline in viral load (serum CMV DNA 2380 IU/mL) was observed. We continued treatment on an outpatient basis as the clinical condition improved with relief of the intestinal syndrome. All other comorbidities were in a stable phase, and we continued methylprednisolone therapy at a low dose (4 mg daily). The CMV DNA was regularly checked and, according to the results, valganciclovir therapy was discontinued after six weeks. Follow–up endoscopy examinations and histological mucosal samples showed no signs of CMV disease. This Figure shows small intestinal mucosa biopsy samples in the patient with CMV infection. The villi were normally dense with epithelium without atypia. The lamina propria was focally mildly fibrosed, moderately infiltrated with mononuclear cell inflammatory infiltrate rich with plasma cells ((<b>B</b>)—area with symbol *). A few eosinophilic and neutrophilic granulocytes were also present in the inflammatory infiltrate. Lymphatic aggregates were present. There were no signs of cryptitis, no crypt microabscesses and no epithelioid granulomas. Immunohistochemical staining revealed nuclear staining in CMV infected cells ((<b>C</b>,<b>D</b>)—marked with arrows). Paraffin-embedded tissue blocks were sectioned with a microtome to obtain 3–5 μm-thick paraffin sections and were placed onto a glass slide (StarFrost; Knittel, Braunschweig, Germany). Hematoxylin and eosin staining was performed on a fully automated VENTANA HE 600 system according to standard protocol. Immunohistochemical staining was performed for the visualization and localization of CMV specific antigens on formalin-fixed, paraffin-embedded tissue samples from terminal ileum. Paraffin-embedded tissue blocks were sectioned with a microtome to obtain 3–5 μm-thick paraffin sections, which were placed onto a glass slide (Superfrost Plus; Epredia, Portsmouth, UK). The tissue slides were dehydrated in a slide-drying ventilation oven for 60 min at 60 °C. IHC staining was carried out on an automated system (BenchMark Ultra; Roche Tissue Diagnostics’, Mannheim, Germany) using detection kits (UltraView Universal DAB detection kit; Roche Tissue Diagnostics’, Mannheim, Germany; cat. no. 05269806001) following the manufacturer’s instructions. A deparaffinization solution (EZPrep solution; Roche Tissue Diagnostics’, Mannheim, Germany; cat. no. 05279771001) was used for 4 min at 72 °C for the complete dissolution of the paraffin. Protease (Protease 1; Roche Tissue Diagnostics’, Mannheim, Germany; cat. no 05266688001) was used for the epitope retrieval for 8 min. The slides were applied and incubated with the primary antibodies anti-CMV (Sigma-Aldrich; Cell Marque, Rocklin, CA, USA; cat. no. 213M-16-RUO, lot: 0000285872) for 24 min at 36 °C (optimized dilution 1:100 in an antibody diluent (Ventana; Roche Tissue Diagnostics’, Mannheim, Germany; cat. no. 05261899001)). The specific anti-CMV antibody was located by a specific secondary antibody to which an enzyme-HRP labelled tertiary antibody was bound. The complex was then visualized with hydrogen peroxide substrate and 3,3′-diaminobenzidine tetrahydrochloride (DAB) chromogen, which produces a brown precipitate that was visible by light microscopy. CMV infection may manifest as the CMV syndrome (fever, malaise, myalgia, etc.) or as tissue-invasive CMV disease. It can affect the gastrointestinal tract from the oral cavity to the anus [<a href="#B3-diagnostics-14-02633" class="html-bibr">3</a>,<a href="#B4-diagnostics-14-02633" class="html-bibr">4</a>]. Detecting the CMV-specific IgM and IgG antibodies demonstrates a primary CMV infection. In immunocompromised patients with clinical signs, the diagnosis of CMV disease requires the presence of CMV DNA in the plasma and histological confirmation of CMV in a tissue or an organ [<a href="#B5-diagnostics-14-02633" class="html-bibr">5</a>]. CMV-specific immunohistochemistry (IHR) is the gold standard for identifying CMV in tissue biopsies [<a href="#B6-diagnostics-14-02633" class="html-bibr">6</a>]. The data showed that CMV infection was detected more frequently if the referring physician requested an IHR for the CMV when the patient was immunocompromised due to either underlying disease or immunosuppressive drugs, if more biopsy specimens were obtained, or if the specimens showed severe inflammation [<a href="#B7-diagnostics-14-02633" class="html-bibr">7</a>,<a href="#B8-diagnostics-14-02633" class="html-bibr">8</a>]. At our center, immunohistochemical staining for CMV is performed either at the clinician’s request for immunocompromised patients or at the pathologist’s request due to microscopic features on biopsy, including the degree and type of inflammation and viral cytopathic effects. The most common manifestation of invasive CMV disease is gastrointestinal involvement. Evidence of CMV colitis requires a characteristic endoscopic picture with ulcers with a well-defined, convex appearance and CMV viral inclusions in the form of an “owl’s eye” on mucosal sections stained with hematoxylin and eosin [<a href="#B4-diagnostics-14-02633" class="html-bibr">4</a>]. Treatment can be challenging as viremia may be low or even absent despite a marked clinical picture of gastrointestinal involvement. Relapses can also be expected; therefore, prolonging antiviral therapy beyond the point at which no CMV DNA is detected in the plasma, is reasonable for optimal treatment. The decision regarding secondary prophylaxis varies [<a href="#B9-diagnostics-14-02633" class="html-bibr">9</a>].</p>
Full article ">Figure 2
<p>(<b>A</b>,<b>B</b>): Abdominal CT with signs of infectious enteritis. Axial (<b>A</b>) and coronal (<b>B</b>) contrast-enhanced CT images showed signs of an infectious enteritis. The capture shows diffused small bowel wall thickening with mucosal hyperenhancement (asterisk) and perienteric fat stranding (arrow). It also shows mesenteric vessel engorgement (arrowhead). The small bowel was affected entirely from the duodenum to the ileocecal valve. We did not confirm ischemic colitis. Conclusion: CMV infection is usually considered in patients with AIDS, hematological malignancies or after tissue and organ transplantation; however, tissue-invasive CMV disease can also appear in an immunocompromised patient due to long-term corticosteroid therapy.</p>
Full article ">
8 pages, 230 KiB  
Review
Examining Infant and Child Neurodevelopmental Outcomes After Lyme Disease During Pregnancy
by Meagan E. Williams, David A. Schwartz, Roberta L. DeBiasi and Sarah B. Mulkey
Pathogens 2024, 13(12), 1029; https://doi.org/10.3390/pathogens13121029 - 22 Nov 2024
Viewed by 219
Abstract
Lyme disease is the most common vector-borne disease in the United States. Recent environmental and socioecological changes have led to an increased incidence of Lyme and other tick-borne diseases, which enhances the urgency of identifying and mitigating adverse outcomes of Lyme disease exposure. [...] Read more.
Lyme disease is the most common vector-borne disease in the United States. Recent environmental and socioecological changes have led to an increased incidence of Lyme and other tick-borne diseases, which enhances the urgency of identifying and mitigating adverse outcomes of Lyme disease exposure. Lyme disease during pregnancy, especially when untreated, may lead to adverse pregnancy and neonatal outcomes; however, long-term child outcomes following utero exposure to Lyme disease have not yet been systematically assessed. This concise review describes the current state of knowledge of Lyme disease as a congenital infection and the potential effects of in utero exposure to Lyme disease infection on the neurodevelopment of infants and children. We highlight the importance of distinguishing between acute Lyme disease and a chronic condition termed Post-Treatment Lyme Disease Syndrome, as the impacts of both conditions on the developing fetus and subsequent child development may differ. The importance of placental pathology for patients with acute or chronic symptoms of Lyme disease in pregnancy is explored. Future research aiming to understand and protect neurodevelopment after antenatal Lyme disease must carefully collect potentially confounding variables such as symptomatology and treatment, use clear and standard case definitions, and follow children into school-age and beyond. Full article
(This article belongs to the Special Issue The Future of Vector-Borne Diseases in a Changing World)
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Graphical abstract

Graphical abstract
Full article ">
8 pages, 1106 KiB  
Article
Clinical Study of Vitamin D Levels in Hospitalized Children with Acute Respiratory Infections
by Gena Stoykova Petkova, Eleonora Nikolaeva Mineva and Venetsia Tsvetkova Botsova
Pediatr. Rep. 2024, 16(4), 1034-1041; https://doi.org/10.3390/pediatric16040088 - 22 Nov 2024
Viewed by 241
Abstract
The aim of our research was to evaluate and analyze serum 25(OH) vitamin D and parathyroid hormone (PTH) levels to investigate whether vitamin D deficiency serves as a risk factor for an increased incidence of acute respiratory infections (ARI) in children. Serum PTH [...] Read more.
The aim of our research was to evaluate and analyze serum 25(OH) vitamin D and parathyroid hormone (PTH) levels to investigate whether vitamin D deficiency serves as a risk factor for an increased incidence of acute respiratory infections (ARI) in children. Serum PTH levels were used as an indicator of vitamin D sufficiency, as normal PTH levels require an optimal concentration of 25(OH) vitamin D. The study included 129 children, divided into five subgroups: children with acute bronchopneumonia (n = 42), acute laryngotracheitis (n = 7), acute bronchiolitis (n = 32), acute bronchitis (n = 18), and a control group (n = 30). No statistically significant differences in 25(OH)D levels were observed between the overall population of children with ARI and the control group (p = 0.073). However, significant differences in 25(OH)D levels were identified between the control group and children with bronchopneumonia, acute bronchitis, and laryngotracheitis (p < 0.01, p < 0.05). Regarding PTH levels, statistical significance was found between the control group and the acute bronchiolitis group, due to the high percentage of children with hypervitaminosis in this subgroup. These results highlight the crucial role of vitamin D in the onset and progression of acute respiratory tract infections in children, emphasizing its impact on their overall respiratory health. Full article
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Figure 1

Figure 1
<p>Distribution of the study population by group: acute bronchiolitis (n = 32), acute bronchopneumonia (n = 42), acute laryngotracheitis (n = 7), acute bronchitis (n = 18), and control group (n = 30).</p>
Full article ">Figure 2
<p>Distribution of the study population based on serum 25 (OH) D levels. <span class="html-italic">p</span> = 0.01.</p>
Full article ">Figure 3
<p>Vitamin D status in children with acute respiratory infections (ARIs) versus healthy controls.</p>
Full article ">
14 pages, 1429 KiB  
Communication
Long-Distance Finding of AOD-Related Bacteria in the Natural Environment: Risks to Quercus ilex (L.) in Italy
by Giambattista Carluccio, Marzia Vergine, Federico Vita, Erika Sabella, Angelo Delle Donne, Luigi De Bellis and Andrea Luvisi
Forests 2024, 15(12), 2055; https://doi.org/10.3390/f15122055 - 21 Nov 2024
Viewed by 224
Abstract
Acute Oak Decline (AOD), a bacterial disease previously known in Northern and Central Europe, has recently been reported in Salento (a Mediterranean coastal region of Southern Italy), where holm oak trees exhibiting AOD-like symptoms have tested positive for infection with AOD-related bacteria such [...] Read more.
Acute Oak Decline (AOD), a bacterial disease previously known in Northern and Central Europe, has recently been reported in Salento (a Mediterranean coastal region of Southern Italy), where holm oak trees exhibiting AOD-like symptoms have tested positive for infection with AOD-related bacteria such as Brenneria goodwinii and Gibbsiella quercinecans. Sampling symptomatic trees, strains BLEC23 (B. goodwinii) and GSAC47 (G. quercinecans) were isolated and identified by partial 16S rRNA and gyrB gene sequencing. Pathogenicity tests demonstrate that these bacteria induce wood necrosis when inoculated in excised branches, providing details for the etiology of AOD in Italy. Phylogenetic analysis indicated a substantial genetic similarity between the Italian strains and those found in various European and non-European countries. These findings leave a space open to the possibility that the bacteria involved in AOD are much more widespread in Europe than the findings indicate, but that their presence is frequently hidden. Full article
(This article belongs to the Section Forest Health)
Show Figures

Figure 1

Figure 1
<p>Phylogenetic tree based on 16S gene sequencing of <span class="html-italic">B. goodwinii</span> strain BLEC23. From the phylogenetic tree, it can be noted how the strain isolated in Italy BLEC23 (▲) of <span class="html-italic">B. goodwinii</span> shows more similarities with the strains (CDN-09-alpha-G) isolated in France on <span class="html-italic">Q. petraea</span>., while <span class="html-italic">B. nigrifluens</span> (BN207), representing the outer layer, is the most genetically distant strain.</p>
Full article ">Figure 2
<p>Phylogenetic tree based on 16S gene sequencing of <span class="html-italic">G. quercinecans</span> strain GSAC47. From the phylogenetic tree, it can be noted how the strain isolated in Italy GSAC47 (▲) of <span class="html-italic">G. quercinecans</span> shows more similarities with the YMM14 strain (from <span class="html-italic">Morus</span> sp. in Iran), while <span class="html-italic">G. greigii</span> (USA 56), representing the outer layer, is the most genetically distant strain.</p>
Full article ">Figure 3
<p>(<b>A</b>,<b>B</b>) Two excised branches inoculated with <span class="html-italic">B. goodwinii</span> and <span class="html-italic">G. quercinecans</span>, respectively. Red arrows indicate the inoculation points, while green arrows indicate the mock-inoculation points. Necrotic wood can be observed at the inoculation points. (<b>C</b>) The incubation conditions of the inoculated wood sections. (<b>D</b>) Brown exudate is observed outside the bark at the inoculation point. The reference bar is equal to 1 cm.</p>
Full article ">
14 pages, 1385 KiB  
Article
A Comparative Analysis of the Impact of Severe Acute Respiratory Syndrome Coronavirus 2 Infection on the Performance of Clinical Decision-Making Algorithms for Pulmonary Embolism
by Merve Eksioglu, Burcu Azapoglu Kaymak, Atilla Halil Elhan and Tuba Cimilli Ozturk
J. Clin. Med. 2024, 13(23), 7008; https://doi.org/10.3390/jcm13237008 - 21 Nov 2024
Viewed by 203
Abstract
Background/Objectives: This study aimed to compare the diagnostic accuracy of the Wells and Geneva scores using a 500 ng/mL D-dimer cutoff, as well as the age-adjusted D-dimer (AADD), YEARS, and pulmonary embolism graduated D-dimer (PEGeD) algorithms, in patients with and without COVID-19. [...] Read more.
Background/Objectives: This study aimed to compare the diagnostic accuracy of the Wells and Geneva scores using a 500 ng/mL D-dimer cutoff, as well as the age-adjusted D-dimer (AADD), YEARS, and pulmonary embolism graduated D-dimer (PEGeD) algorithms, in patients with and without COVID-19. Various D-dimer cutoffs were also evaluated. Methods: This retrospective study included emergency department patients who underwent computed tomography pulmonary angiography (CTPA) for suspected pulmonary embolism (PE). The diagnostic performances of clinical prediction algorithms were compared between COVID-19-positive and -negative groups. Results: We analyzed data from 1423 patients; the PE and COVID-19 positivity rates were 7.3% and 69.9%, respectively. In COVID-19-positive patients, the Wells score with a 500 ng/mL D-dimer cutoff demonstrated 97.22% sensitivity (95% CI: 80.53–100.00) and 4.99% specificity (95% CI: 3.58–6.39). Using AADD raised the specificity to 7.81% (95% CI: 6.08–9.54) while maintaining 97.22% sensitivity (95% CI: 93.43–100.00); similar findings were observed with the Geneva score. The YEARS algorithm had 86.11% sensitivity (95% CI: 78.12–94.10) and 32.75% specificity (95% CI: 29.73–35.78), whereas the PEGeD algorithm showed 86.11% sensitivity (95% CI: 78.12–94.10) and 34.06% specificity (95% CI: 31.00–37.12). Both algorithms demonstrated slightly improved specificity and accuracy in COVID-19-positive patients. Conclusions: The YEARS and PEGeD algorithms showed slight improvements in specificity and accuracy among COVID-19-positive patients. The Wells and Geneva scores maintained higher sensitivity but lower specificity across groups. Adjusting the D-dimer cutoffs increased the specificity but increased the risk of missed diagnoses. Overall, COVID-19 had a minimal impact on PE diagnostic algorithm performances. Full article
(This article belongs to the Section Emergency Medicine)
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<p>Study flowchart. Abbreviations: CTPA, computed tomography pulmonary angiography; PE, pulmonary embolism. Note: “Incomplete medical records” indicates cases missing key documentation on symptoms, history, or findings, which are needed for calculating pretest scores.</p>
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<p>Receiver operating characteristic curves for Wells + age-adjusted D-dimer and Wells + D-dimer 500 ng/mL cutoffs in COVID-19-positive and -negative patients for predicting pulmonary embolism.</p>
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<p>Receiver operating characteristic curves for Geneva scores combined with age-adjusted D-dimer and Geneva scores with a D-dimer cutoff of 500 ng/mL in COVID-19-positive and -negative patients for predicting pulmonary embolism.</p>
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<p>Receiver operating characteristic curves for the diagnostic performance of the YEARS algorithm (<b>left</b>) and PEGeD algorithm (<b>right</b>) in predicting pulmonary embolism among COVID-19-positive and -negative patient groups.</p>
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17 pages, 2131 KiB  
Review
Modulation of Monocyte Effector Functions and Gene Expression by Human Cytomegalovirus Infection
by Matthew S. Planchon, Jay A. Fishman and Joseph El Khoury
Viruses 2024, 16(12), 1809; https://doi.org/10.3390/v16121809 - 21 Nov 2024
Viewed by 240
Abstract
Monocytes are crucial players in innate immunity. The human cytomegalovirus (CMV) infection has significant impacts on monocyte effector functions and gene expression. CMV, a β-herpesvirus, disrupts key monocyte roles, including phagocytosis, antigen presentation, cytokine production, and migration, impairing their ability to combat pathogens [...] Read more.
Monocytes are crucial players in innate immunity. The human cytomegalovirus (CMV) infection has significant impacts on monocyte effector functions and gene expression. CMV, a β-herpesvirus, disrupts key monocyte roles, including phagocytosis, antigen presentation, cytokine production, and migration, impairing their ability to combat pathogens and activate adaptive immune responses. CMV modulates monocyte gene expression, decreasing their capacity for antigen presentation and phagocytosis while increasing pro-inflammatory cytokine production, which can contribute to tissue damage and chronic inflammation. CMV also alters monocyte migration to sites of infection while promoting trans-endothelial migration, thus aiding viral dissemination. Additionally, the virus affects reactive oxygen species (ROS) production, thereby contributing to end-organ disease associated with CMV infection. Overall, these changes enhance viral persistence during acute infection and facilitate immune evasion during latency. We highlight the clinical significance of these disruptions, particularly in immunocompromised patients such as transplant recipients, where the modulation of monocyte function by CMV exacerbates risks for infection, inflammation, and graft rejection. An understanding of these mechanisms will inform therapeutic strategies to mitigate CMV-related complications in vulnerable populations. Full article
(This article belongs to the Special Issue Immune Modulation by Human Cytomegalovirus)
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<p>Monocyte effector functions.</p>
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<p>CMV interacts with monocytes via β1 and β3 integrins and EGFR.</p>
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<p>CMV infection modulates monocyte phagocytic function.</p>
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<p>CMV modulates antigen presentation by monocytes.</p>
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<p>CMV modulates monocyte cytokine production.</p>
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<p>CMV modulates monocyte migration and chemotaxis.</p>
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6 pages, 499 KiB  
Brief Report
Relationship Between Plasma Acid Sphingomyelinase and Alteration in Taste and Smell as Indicator of Long COVID in Pregnant Women
by Federico Fiorani, Giulia Moretti, Laura Cerquiglini, Chiara Gizzi, Giulia Gizzi, Paola Signorelli, Samuela Cataldi, Tommaso Beccari, Elisa Delvecchio, Claudia Mazzeschi, Stefania Troiani and Elisabetta Albi
Reports 2024, 7(4), 104; https://doi.org/10.3390/reports7040104 - 21 Nov 2024
Viewed by 314
Abstract
Background: Persistent alterations in taste and smell affect a significant proportion of individuals following COVID-19, representing a component of post-acute COVID-19 syndrome, commonly referred to as long COVID. The degradation of sphingomyelin by acid sphingomyelinase is regarded as a biomarker for acquired demyelinating [...] Read more.
Background: Persistent alterations in taste and smell affect a significant proportion of individuals following COVID-19, representing a component of post-acute COVID-19 syndrome, commonly referred to as long COVID. The degradation of sphingomyelin by acid sphingomyelinase is regarded as a biomarker for acquired demyelinating neuropathies. Objectives: This study was aimed to enroll women who contracted COVID-19 during pregnancy and experienced persistent alterations in taste and/or smell for more than 1 year post-infection, in comparison to pregnant women without any disturbances in these senses. Methods: The patients were subjected to a questionnaire investigating smell and taste disorders more than 1 year after the infection. Then, the levels of acid sphingomyelinase in the plasma of the participants were assessed. Results: The results showed that in women who had been pregnant and who had been infected with SARS Cov-2 during the COVID period and who still had taste and smell disorders 1 year later, plasma acid sphingomyelinase levels were double that of pregnant women who had contracted the infection during the COVID period but had not reported taste and smell disorders and that of pregnant women analyzed after the COVID period. Conclusions: The results suggest a hypothesis that the persistence of sensory disturbances in long COVID was probably due to a failure to utilize brain circuitry with demyelination resulting from chemosensory dysfunction of the olfactory epithelium. Full article
(This article belongs to the Section Obstetrics/Gynaecology)
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<p>aSMase level in the serum of women who had infection of SARS-CoV-2 in pregnancy one year before the analysis. Comparison among women controls (CTR, 10 mothers), women who had alterations in taste and/or smell (eight mothers) and women without alterations (five mothers). Data were expressed as the mean ± SD of three independent experiments performed in triplicate for each patient. * <span class="html-italic">p</span> &lt; 0.05 women with disturbance in taste and smell versus women without disturbance in taste and smell and versus CTR.</p>
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<p>Expression of SMPD1 gene in serum of women who had infection of SARS-CoV-2 in pregnancy one year before the analysis. GAPDH and 18S rRNA were used as housekeeping genes. mRNA relative expression levels were calculated as 2<sup>−ΔΔCt</sup>, comparing the results of the COVID-19 patients with the control sample (CTR, without COVID-19) equal to one, the origin of the axes. Data are expressed as the mean ± SD of three independent experiments performed in duplicate for each patient. * <span class="html-italic">p</span> &lt; 0.05 versus CTR.</p>
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10 pages, 8510 KiB  
Case Report
First Detection of West Nile Virus by Nasopharyngeal Swab, Followed by Phylogenetic Analysis
by Carlo Zuddas, Sergio Piras, Stefano Cappai, Federica Loi, Giulia Murgia, Giantonella Puggioni, Giovanni Savini, Federica Monaco, Andrea Polci, Fabrizia Valleriani, Giorgia Amatori, Valentina Curini, Maurilia Marcacci, Germano Orrù, Antonio Ledda, Elena Poma, Riccardo Cappai and Ferdinando Coghe
Pathogens 2024, 13(11), 1023; https://doi.org/10.3390/pathogens13111023 - 20 Nov 2024
Viewed by 266
Abstract
West Nile Virus, an arthropod-borne RNA virus, may result in severe neurological disease. West Nile neuroinvasive disease is characterized by meningitis, encephalitis, and possible acute flaccid paralysis. Here, we report a case of neuroinvasive WNV in a 65-year-old woman hospitalized for hyperpyrexia, chills, [...] Read more.
West Nile Virus, an arthropod-borne RNA virus, may result in severe neurological disease. West Nile neuroinvasive disease is characterized by meningitis, encephalitis, and possible acute flaccid paralysis. Here, we report a case of neuroinvasive WNV in a 65-year-old woman hospitalized for hyperpyrexia, chills, intense asthenia, and continuous vomiting. Within days, her clinical condition worsened with the onset of severe neurological symptoms, leading to her death within 10 days despite supportive therapies being administered. The diagnosis of West Nile disease was made through nucleic acid amplification testing (NAAT) on blood and cerebrospinal fluid. However, in the final stages of the illness, cerebrospinal fluid collection was not possible due to the patient’s critical condition, and a nasopharyngeal swab was used instead. The nasopharyngeal swab facilitated the collection of a sample, which was subsequently analyzed for the presence of the virus and allowed for sequencing, showing that it was a strain that had been circulating in Sardinia for some time and had demonstrated its pathogenicity by causing the death of a hawk in 2021. This case report highlights the rapid progression and severity of WNV infection, particularly in vulnerable individuals, and suggests the potential utility of nasopharyngeal swabs as a less invasive option for sample collection. It also underscores the potential for the zoonotic transmission of the virus from birds to humans through vectors, emphasizing the importance of monitoring and controlling WNV outbreaks, especially in regions where such circulation is observed. Full article
(This article belongs to the Special Issue Emerging Zoonoses)
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<p>The evolutionary history was inferred using IQTREE 1.6.12 using command line: iqtree –s AlignWNVL2_CDS.fa –st DNA –m TEST –bb 10,000 –alrt 10,000 –abayes. The optimal tree is shown. The percentage of posterior probabilities in which the associated taxa clustered together are shown next to the branches. The tree is drawn to scale, with branch lengths measured in substitutions per site and optimized by maximum likelihood on original alignment. Model selection was carried out on all datasets using ModelFinder implemented in IQTREE. The rate variation among sites was modeled with GTR + F + I + G4, and the best fit model was chosen according to Bayesian Information Criterion (BIC). The tree is radicated to DQ116961 Hungary 2004 sequence. The node shapes are sized by posterior probabilities (PPs). The red nodes have posterior probabilities &gt; 80%, while the blue nodes have posterior probabilities &lt; 80%.</p>
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<p>Enlargement of the Italian sub-clade of the tree reported in <a href="#pathogens-13-01023-f001" class="html-fig">Figure 1</a>. This clade includes all the Italian WNV-L2 from 2012 to 2022. The WNV-L2 strain NRG6464 (PP625328) is colored in red.</p>
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14 pages, 1007 KiB  
Article
Insights into the Risk Factors and Outcomes of Post-COVID-19 Syndrome—Results from a Retrospective, Cross-Sectional Study in Romania
by Ioana Bejan, Corneliu Petru Popescu and Simona Maria Ruta
Life 2024, 14(11), 1519; https://doi.org/10.3390/life14111519 - 20 Nov 2024
Viewed by 256
Abstract
Post-Coronavirus Disease 2019 (post-COVID-19) syndrome represents a cluster of persistent symptoms following Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection that can severely affect quality of life. The pathogenic mechanisms and epidemiology in different regions are still under evaluation. To assess the outcomes [...] Read more.
Post-Coronavirus Disease 2019 (post-COVID-19) syndrome represents a cluster of persistent symptoms following Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection that can severely affect quality of life. The pathogenic mechanisms and epidemiology in different regions are still under evaluation. To assess the outcomes of post-COVID-19 syndrome, we performed a questionnaire-based, cross-sectional study in previously infected individuals. Out of 549 respondents, (male:female ratio: 0.32), 29.5% had persistent symptoms at 3 months, 23.5% had persistent symptoms at 6 months, and 18.3% had persistent symptoms at 12 months after the initial infection. The most common symptoms included fatigue (8.7%), sleep disturbances (7.1%), and cognitive impairment (6.4%). The risk of developing post-COVID-19 syndrome increased for those with more symptoms in the acute phase (OR 4.24, p < 0.001) and those experiencing reinfections (OR 2.405, p < 0.001), while SARS-CoV-2 vaccination halved the risk (OR = 0.489, p = 0.004). Individuals with post-COVID-19 syndrome had a 5.7-fold higher risk of being diagnosed with a new chronic condition, with 44% reporting cardiovascular disease, and a 6.8-fold higher likelihood of needing medical care or leave. Affected individuals reported significant impairments in mobility, pain/discomfort, and anxiety/depression, with 20.7% needing to adjust their work schedules. Overall, patients with post-COVID-19 syndrome require ongoing monitoring and rehabilitation, and further socio-economic impact studies are needed. Full article
(This article belongs to the Special Issue Human Health Before, During, and After COVID-19)
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<p>SARS-CoV-2 infections reported in the study cohort throughout the pandemic and the dominant viral variant at that time in Romania.</p>
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<p>Impact of the different risk factors on the development of post-COVID-19 syndrome. (<b>A</b>) number of symptoms during the acute phase of the infection, (<b>B</b>) number of pre-infection comorbidities, (<b>C</b>) vaccination status.</p>
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<p>Impact of the different risk factors on the development of post-COVID-19 syndrome. (<b>A</b>) number of symptoms during the acute phase of the infection, (<b>B</b>) number of pre-infection comorbidities, (<b>C</b>) vaccination status.</p>
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<p>Average self-assessed health status for five areas of quality of life: Panel (<b>A</b>)—Pre-infection with SARS-CoV-2—comparison between subjects later diagnosed with long COVID and those unaffected; Panel (<b>B</b>)—Post-infection with SARS-CoV-2—comparison between subjects later diagnosed with long COVID and those unaffected, adapted from the EuroQoL 5D-3L scale [<a href="#B13-life-14-01519" class="html-bibr">13</a>]. Attributable scores ranged from 1—complete independence and lack of discomfort to 3—severe problems in the specified category.</p>
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23 pages, 3398 KiB  
Article
Unveiling the Role of TMPRSS2 in the Proteolytic Activation of Pandemic and Zoonotic Influenza Viruses and Coronaviruses in Human Airway Cells
by Marie Schwerdtner, Luna C. Schmacke, Julia Nave, Hannah Limburg, Torsten Steinmetzer, David A. Stein, Hong M. Moulton and Eva Böttcher-Friebertshäuser
Viruses 2024, 16(11), 1798; https://doi.org/10.3390/v16111798 - 20 Nov 2024
Viewed by 393
Abstract
The zoonotic transmission of influenza A viruses (IAVs) and coronaviruses (CoVs) may result in severe disease. Cleavage of the surface glycoproteins hemagglutinin (HA) and spike protein (S), respectively, is essential for viral infectivity. The transmembrane serine protease 2 (TMPRSS2) is crucial for cleaving [...] Read more.
The zoonotic transmission of influenza A viruses (IAVs) and coronaviruses (CoVs) may result in severe disease. Cleavage of the surface glycoproteins hemagglutinin (HA) and spike protein (S), respectively, is essential for viral infectivity. The transmembrane serine protease 2 (TMPRSS2) is crucial for cleaving IAV HAs containing monobasic cleavage sites and severe acute respiratory syndrome (SARS)-CoV-2 S in human airway cells. Here, we analysed and compared the TMPRSS2-dependency of SARS-CoV, Middle East respiratory syndrome (MERS)-CoV, the 1918 pandemic H1N1 IAV and IAV H12, H13 and H17 subtypes in human airway cells. We used the peptide-conjugated morpholino oligomer (PPMO) T-ex5 to knockdown the expression of active TMPRSS2 and determine the impact on virus activation and replication in Calu-3 cells. The activation of H1N1/1918 and H13 relied on TMPRSS2, whereas recombinant IAVs carrying H12 or H17 were not affected by TMPRSS2 knockdown. MERS-CoV replication was strongly suppressed in T-ex5 treated cells, while SARS-CoV was less dependent on TMPRSS2. Our data underline the importance of TMPRSS2 for certain (potentially) pandemic respiratory viruses, including H1N1/1918 and MERS-CoV, in human airways, further suggesting a promising drug target. However, our findings also highlight that IAVs and CoVs differ in TMPRSS2 dependency and that other proteases are involved in virus activation. Full article
(This article belongs to the Special Issue TMPRSS2 in Influenza Virus and Coronavirus Infections)
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<p><b>Schematic representation of CoV S and IAV HA.</b> CoV S (<b>A</b>) and IAV HA (<b>B</b>) are synthesized as the inactive precursor proteins S0 and HA0, respectively, which require proteolytic processing for activation. Cleavage sites are indicated by arrows. Recombinant S was expressed with a C-terminal FLAG-tag in this study. FP = fusion peptide, TM = transmembrane domain.</p>
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<p><b>Efficiency of TMPRSS2 cleavage of SARS-CoV and MERS-CoV S.</b> (<b>A</b>) P6-P3′ amino acid sequences of the synthesized and analysed FRET substrates representing the CoV S cleavage site motifs, which all contain an N-terminal o-aminobenzoyl fluorophore and a C-terminal Tyr(3-NO<sub>2</sub>)-NH<sub>2</sub> as a quenching residue. The TMPRSS2 cleavage site is indicated by a red arrow. (<b>B</b>) The cleavage efficiency of the FRET substrates by recombinant TMPRSS2 was measured in an enzyme kinetic assay. The data shown are the mean values + SD based on three independent measurements with three independent weights of the substrates. (<b>C</b>) HeLa cells were transfected with plasmids encoding C-terminally FLAG-tagged SARS-CoV or MERS-CoV S, and TMPRSS2. Simultaneously, HeLa cells were treated with 50 µM MI-1851 or remained untreated. At 48 h after transfection and inhibitor treatment, the cell lysates were subjected to SDS-PAGE and Western blot analysis with an antibody targeting the S2 subunit of SARS-CoV S or the C-terminal FLAG-tag of MERS-CoV S. The data shown are the representative results of three independent experiments.</p>
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<p><b>Activation of SARS-CoV and MERS-CoV S by TMPRSS2 and further host proteases.</b> (<b>A</b>,<b>B</b>) HeLa cells were co-transfected with plasmids coding for MERS-CoV S (<b>A</b>) or SARS-CoV (<b>B</b>) with a C-terminal FLAG-tag and plasmids coding for human TMPRSS2 or HAT or murine TMPRSS4 or TMPRSS13. Cell lysates were analysed via SDS-PAGE at 48 h p.t. Western blot analysis was performed using an antibody targeting the C-terminal FLAG-tag. Tubulin was used as a loading control. The data shown are representative of three individual experiments. EV = empty vector. (<b>C</b>,<b>E</b>) HeLa cells co-expressing MERS-CoV (<b>C</b>) or SARS-CoV (<b>E</b>) S, as well as the respective receptors DPP4 or ACE2, were incubated for 48 h. After fixation, the cells were stained with a primary antibody targeting the C-terminal FLAG-tag of S and a fluorescence-coupled secondary antibody. DAPI was used to stain the nuclei. Representative images of three independent experiments are shown. The scale bar represents 100 µM. (<b>D</b>,<b>F</b>) Quantification of MERS-CoV S (<b>D</b>) or SARS-CoV (<b>F</b>) mediated cell–cell fusion. For each condition, ten randomly taken images were analysed by counting the nuclei per syncytium (with at least three nuclei). The data shown are the mean values + SEM of three independent experiments. Statistical significance was determined with a one-way ANOVA followed by Šídák’s multiple comparisons test. ns = not significant, ** = <span class="html-italic">p</span> &lt; 0.01, **** = <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p><b>Protease dependency of the multicycle replication of SARS-CoV and MERS-CoV in Calu-3 cells.</b> (<b>A</b>–<b>C</b>) Calu-3 cells were treated with or without 25 µM T-ex5 for 24 h. The cells were then infected with MERS-CoV at an MOI of 0.001. After inoculation with the virus for 1 h, cells were treated with 50 µM MI-1851 or remained untreated. Viral titers in the supernatant sampled at the indicated time points were determined via TCID<sub>50</sub> endpoint titration. The data shown are the mean + SD of three independent experiments. The dotted lines indicate the limit of detection (LOD). (<b>D</b>) Calu-3 cells treated with 5, 15 or 25 µM T-ex5 or left untreated were infected with MERS-CoV at an MOI of 1 and treated with 5, 10 or 50 µM MI-1851 or no inhibitor after 1 h inoculation. At 24 h p.i., the cell lysates and supernatant were subjected to SDS-PAGE, and Western blot analysis was performed with antibodies targeting the S2 subunit of MERS-CoV S. For the cell lysates, ß-actin was stained as a loading control. The data shown are the representative results of three independent experiments. (<b>E</b>,<b>G</b>–<b>J</b>) Calu-3 cells pre-treated with 25 µM T-ex5 for 24 h or left untreated were infected with SARS-CoV at an MOI of 0.001. After 1 h, the cells were washed and treated with 50 µM MI-1851 (<b>G</b>), 50 µM aprotinin (<b>H</b>), 50 µM E64d or DMSO (<b>I</b>,<b>J</b>). The supernatant was sampled at 0, 24, 48 and 72 h p.i. and the viral titers were determined via TCID<sub>50</sub> endpoint titration. The experiments were performed three times and the data shown are mean + SD. The dotted lines indicate the LOD. (<b>F</b>,<b>K</b>) Calu-3 cells infected with SARS-CoV at an MOI of 1 were either pre-treated with 25 µM of T-ex5 or treated with 50 µM of the different inhibitors at 1 h after inoculation. After an additional 24 h, the cell lysates and supernatants were harvested for SDS-PAGE. Western blot analysis was performed with an antibody targeting the S2 subunit of SARS-CoV S and ß-actin was used as a loading control. The results are representative of three individual experiments. (<b>L</b>) Calu-3 cells were treated with 25 µM T-ex5 and/or 50 µM of the different inhibitors, or remained untreated, as in the previous experiments. At 72 h after inhibitor treatment, the cell viability was assessed and untreated cells were set to 100%, and inhibitors or combinations with over 80% cell viability (dotted line) were considered non-toxic. Treatment with 10% ethanol for 24 h served as a positive control. The data shown are the mean + SD of two independent experiments each performed in a technical triplicate. To determine the statistical significance of the differences in viral titers compared to untreated or DMSO-treated controls, an unpaired <span class="html-italic">t</span>-test (<b>A</b>,<b>B</b>,<b>E</b>,<b>G</b>–<b>I</b>) or a one-way ANOVA followed by Tukey’s multiple comparisons test (<b>C</b>,<b>J</b>) was performed for each individual time point. ns = not significant, * = <span class="html-italic">p</span> &lt; 0.05, ** = <span class="html-italic">p</span> &lt; 0.01, *** = <span class="html-italic">p</span> &lt; 0.001, **** = <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p><b>TMPRSS2 dependency of H1N1/1918, H12, H13 and H17.</b> (<b>A</b>) Sequence alignment of the cleavage sites from different HAs. (<b>B</b>) HEK293 cells transiently expressing the H1/1918 and human TMPRSS2 or HAT, or murine TMPRSS4 or TMPRSS13 were subjected to SDS-PAGE at 48 h p.t. Western blot analysis was performed with an antibody targeting H1. Tubulin was stained as a loading control. The result shown is representative of three independent experiments. EV = empty vector. (<b>C</b>) Calu-3 cells were treated with 25 µM T-ex5 for 24 h before being infected with rH1N1/1918 at an MOI of 0.001. Viral titers in the supernatant sampled at the indicated time points were determined via TCID<sub>50</sub> endpoint titration. The data shown are the mean + SD of three individual experiments. The dotted lines indicate the LOD. (<b>D</b>) The cell lysates and supernatants (SN) of Calu-3 cells treated with 25 µM of T-ex5 for 24 h and then infected with rH1N1/1918 at an MOI of 1 for another 24 h were subjected to SDS-PAGE, and an antibody targeting H1 was used for the Western blot analysis. ß-actin was used as a control. The result is representative of three independent experiments. (<b>E</b>) Calu-3 cells pre-treated with 25 µM were infected with recombinant viruses containing avian H12 or H13 or bat-derived H17 and sharing the other seven gene segments of SC35M at a low MOI of 0.01–0.0001. The supernatant of infected cells was harvested at indicated time points and the viral titers were determined via an immune plaque assay. The experiments were performed in triplicate and the data shown are mean + SD. The dotted lines indicate the LOD. (<b>C</b>,<b>E</b>) Statistically significant differences in viral titers at each time point compared to untreated controls were determined by performing unpaired t-tests. ns = not significant, ** = <span class="html-italic">p</span> &lt; 0.01, *** = <span class="html-italic">p</span> &lt; 0.001, **** = <span class="html-italic">p</span> &lt; 0.0001.</p>
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16 pages, 1365 KiB  
Article
Low-Dose Ketone Monoester Administration in Adults with Cystic Fibrosis: A Pilot and Feasibility Study
by Eric P. Plaisance, Jonathan M. Bergeron, Mickey L. Bolyard, Heather Y. Hathorne, Christina M. Graziano, Anastasia Hartzes, Kristopher R. Genschmer, Jessica A. Alvarez, Amy M. Goss, Amit Gaggar and Kevin R. Fontaine
Nutrients 2024, 16(22), 3957; https://doi.org/10.3390/nu16223957 - 19 Nov 2024
Viewed by 477
Abstract
Introduction: Cystic fibrosis transmembrane conductance regulator (CFTR) modulators have greatly improved outcomes in persons with CF (pwCF); however, there is still significant heterogeneity in clinical responses, particularly with regard to respiratory infection and inflammation. Exogenous administration of ketones has profound systemic [...] Read more.
Introduction: Cystic fibrosis transmembrane conductance regulator (CFTR) modulators have greatly improved outcomes in persons with CF (pwCF); however, there is still significant heterogeneity in clinical responses, particularly with regard to respiratory infection and inflammation. Exogenous administration of ketones has profound systemic anti-inflammatory effects and produces several nutrient-signaling and metabolic effects that may benefit multiple organ systems affected in pwCF. This pilot study was designed to determine the feasibility of administration of a ketone monoester (KME) to increase circulating D-beta hydroxybutyrate concentrations (D-βHB) and to improve subjective measures of CF-specific quality of life and markers of inflammation in serum and sputum in adults with CF. Methods: Fourteen participants receiving modulator therapy were randomized to receive either KME (n = 9) or placebo control (PC, n = 5) for 5–7 days during hospitalization for treatment of acute pulmonary exacerbation or as outpatients under standard care. Results: The KME was well tolerated, with only mild reports of gastrointestinal distress. D-βHB concentrations increased from 0.2 ± 0.1 mM to 1.6 ± 0.6 mM in the KME group compared to 0.2 ± 0.0 to 0.3 ± 0.1 in the PC group (p = 0.011) within 15 min following consumption and remained elevated, relative to baseline, for over 2 h. Pulmonary function was not altered after single- or short-term KME administration, but participants in the KME group self-reported higher subjective respiratory scores compared to PC in both cases (p = 0.031). Plasma inflammatory markers were not statistically different between groups following the short-term (5–7 d) intervention (p > 0.05). However, an exploratory analysis of plasma pre- and post-IL-6 concentrations was significant (p = 0.028) in the KME group but not PC. Sputum IFNγ (p = 0.057), IL-12p70 (p = 0.057), IL-1β (p = 0.100), IL-15 (p = 0.057), IL-1α (p = 0.114), and MPO (p = 0.133) were lower in the KME group compared to PC but did not achieve statistical significance. Conclusions: With the emerging role of exogenous ketones as nutrient signaling molecules and mediators of metabolism, we showed that KME is well tolerated, increases circulating D-βHB concentrations, and produces outcomes that justify the need for large-scale clinical trials to investigate the role of KME on whole-body and tissue lipid accumulation and inflammation in pwCF. Full article
(This article belongs to the Section Nutrition and Public Health)
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<p>Study flow.</p>
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<p>CONSORT diagram.</p>
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<p>D-beta hydroxybutyrate (D-βHB) after the first dose (<b>A</b>) and final dose (<b>B</b>) of KME or PC. Values are means ± SD. Significance was set a priori at <span class="html-italic">p</span> &lt; 0.05. * = Significant group x time interaction.</p>
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<p>Values are individual sputum inflammatory marker responses for (<b>a</b>) interferon γ (IFG), (<b>b</b>) interleukin-12p70 (IL-12p70), (<b>c</b>) interleukin-1β (IL-1β), (<b>d</b>) interleukin 6 (IL-6), (<b>e</b>) interleukin 15 (IL-15), (<b>f</b>) interleukin 16 (IL-16), (<b>g</b>) tumor necrosis factor α (TNFα).</p>
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<p>Values are individual sputum inflammatory marker responses. (<b>a</b>) NE = neuroelastin, (<b>b</b>) MPO = myeloperoxidase, (<b>c</b>) MMP9 matrix metalloproteinase 9.</p>
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10 pages, 3027 KiB  
Article
Microdetection of Nucleocapsid Proteins via Terahertz Chemical Microscope Using Aptamers
by Xue Ding, Mana Murakami, Jin Wang, Hirofumi Inoue and Toshihiko Kiwa
Sensors 2024, 24(22), 7382; https://doi.org/10.3390/s24227382 - 19 Nov 2024
Viewed by 424
Abstract
In the detection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), several methods have been employed, including the detection of viral ribonucleic acid (RNA), nucleocapsid (N) proteins, spike proteins, and antibodies. RNA detection, primarily through polymerase chain reaction tests, targets the viral [...] Read more.
In the detection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), several methods have been employed, including the detection of viral ribonucleic acid (RNA), nucleocapsid (N) proteins, spike proteins, and antibodies. RNA detection, primarily through polymerase chain reaction tests, targets the viral genetic material, whereas antigen tests detect N and spike proteins to identify active infections. In addition, antibody tests are performed to measure the immune response, indicating previous exposure or vaccination. Here, we used the developed terahertz chemical microscope (TCM) to detect different concentrations of N protein in solution by immobilizing aptamers on a semiconductor substrate (sensing plate) and demonstrated that the terahertz amplitude varies as the concentration of N proteins increases, exhibiting a highly linear relationship with a coefficient of determination (R2 = 0.9881), indicating that a quantitative measurement of N proteins is achieved. By optimizing the reaction conditions, we confirmed that the amplitude of the terahertz wave was independent of the solution volume. Consequently, trace amounts (0.5 μL) of the N protein were successfully detected, and the detection process only took 10 min. Therefore, this study is expected to develop a rapid and sensitive method for the detection and observation of the SARS-CoV-2 virus at a microdetection level. It is anticipated that this research will significantly contribute to reducing the spread of novel infectious diseases in the future. Full article
(This article belongs to the Section Biosensors)
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<p>(<b>a</b>) Optical system diagram of the TCM, where the femtosecond laser is divided by a beam splitter into a pump wave that irradiates the sensing plate to generate terahertz waves and a probe beam that penetrates the photoconductor antenna for detecting the generated waves. (<b>b</b>) Schematic diagram of the sensing plate and terahertz waves radiated by the sensing plate. (<b>c</b>) Cross-section of the sensing plate used as the terahertz wave generator. When a femtosecond laser is irradiated onto the sensing plate from the sapphire film, the carriers in the silicon layer are excited and accelerated by the electric field of the depletion layer at the interface between the silicon and silicon oxide, generating an instantaneous current and a terahertz wave proportional to the time derivative of the instantaneous current. (<b>d</b>) Photograph of the sensing plate fixed to the measurement substrate. (<b>e</b>) Cross-section of the measurement substrate.</p>
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<p>Schematic of the experimental design on the sensing plate. (<b>a</b>–<b>d</b>) Modification of SiO<sub>2</sub> film. (<b>e</b>) Immobilization of aptamers by the avidin–biotin reaction; the reaction was measured using the TCM on the sensing plate to obtain the terahertz amplitude before the N protein reaction. (<b>f</b>) Addition of N protein for specific reactions with aptamers. (<b>g</b>) After removing the unreacted N protein, the reaction was measured using the TCM to obtain the terahertz amplitude after the N protein reaction.</p>
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<p>(<b>a</b>) Distribution of terahertz amplitudes on the sensing plate after the immobilization of the aptamers. (<b>b</b>) Distribution of terahertz amplitudes on the sensing plate after the N protein reaction. (<b>c</b>) Terahertz wave amplitude changes on the sensing plate prior to and after the N protein reaction. (<b>d</b>) The change in terahertz wave amplitude following the reaction of N protein at a concentration of 100 ng/mL with aptamers at concentrations of 5, 50, and 500 µg/mL, respectively.</p>
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<p>Surface conditions and height profiles after avidin and aptamers binding to sensing plates via AFM. (<b>a</b>,<b>b</b>) Overall surface condition and height profile after avidin; the arithmetic mean roughness (Sa) was approximately 4.79 nm. (<b>c</b>,<b>d</b>) Overall surface condition and height profile after aptamers; the Sa was approximately 5.86 nm.</p>
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<p>(<b>a</b>) Imaging after aptamer interaction with N protein at different concentrations (0–50 ng/mL) via TCM. The area of the black squares (2.0 × 2.0 mm) was used to calculate the average terahertz amplitude. The amplitude of the terahertz wave (color intensity) changed with a change in the N protein concentration. Contour images were obtained using Origin 2020 software. (<b>b</b>) Quantitative analysis of interactions between the aptamers and N protein. The error bars indicate the standard deviation (<span class="html-italic">n</span> = 4).</p>
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<p>(<b>a</b>–<b>d</b>) Imaging after aptamer interaction with N protein at different concentrations (0–100 ng/mL) via TCM. The area of the black squares (1.0 × 1.0 mm) was used to calculate the average terahertz amplitude. The amplitude of the terahertz wave (color intensity) changed with a change in the N protein concentration. Contour images were obtained using Origin 2020 software. (<b>e</b>) The variations in terahertz wave amplitude across different concentrations of the N protein at varying sample volumes. (<b>f</b>) A quantitative analysis of the interactions between aptamers and the N protein. Error bars represent the standard deviation (<span class="html-italic">n</span> = 9).</p>
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19 pages, 779 KiB  
Review
Beyond Antivirals: Alternative Therapies for Long COVID
by Achilleas Livieratos, Charalambos Gogos and Karolina Akinosoglou
Viruses 2024, 16(11), 1795; https://doi.org/10.3390/v16111795 - 19 Nov 2024
Viewed by 315
Abstract
Long COVID or Post-Acute Sequelae of SARS-CoV-2 infection (PASC) is a condition characterized by numerous lingering symptoms that persist for weeks to months following the viral illness. While treatment for PASC is still evolving, several therapeutic approaches beyond traditional antiviral therapies are being [...] Read more.
Long COVID or Post-Acute Sequelae of SARS-CoV-2 infection (PASC) is a condition characterized by numerous lingering symptoms that persist for weeks to months following the viral illness. While treatment for PASC is still evolving, several therapeutic approaches beyond traditional antiviral therapies are being investigated, such as immune-modulating agents, anti-inflammatory drugs, and various supportive interventions focusing at alleviating symptoms and enhancing recovery. We aimed to summarize the breadth of available evidence, identify knowledge gaps, and highlight promising non-antiviral therapies for Long COVID/PASC. We followed the framework of a scoping methodology by mapping existing evidence from a range of studies, including randomized clinical trials, observational research, and case series. Treatments evaluated include metformin, low-dose naltrexone (LDN), dexamethasone, statins, omega-3 fatty acids, L-arginine, and emerging therapies like intravenous immunoglobulin (IVIg) and therapeutic apheresis. Early findings suggest that metformin has the strongest clinical evidence, particularly from large phase 3 trials, while LDN and dexamethasone show potential based on observational studies. However, many treatments lack robust, large-scale trials. This review emphasizes the need for further research to confirm the efficacy of these treatments and guide clinical practice for Long COVID management. Full article
(This article belongs to the Special Issue Women in Virology 2024)
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<p>Methodological process for selecting Long COVID articles.</p>
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<p>Available treatments for Long COVID patients and main outcomes.</p>
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12 pages, 1221 KiB  
Article
Evaluating the Efficacy of Inhaled Colistin via Two Nebulizer Types in Ventilator-Associated Pneumonia: Prospective Randomized Trial
by Chung-Chi Huang, Tien-Pei Fang, Chieh-Mo Lin, Chien-Ming Chu, Hsuan-Ling Hsiao, Jui-Fang Liu, Hsin-Hsien Li, Li-Chung Chiu, Kuo-Chin Kao, Chin-Hsi Kuo, Shaw-Woei Leu and Hui-Ling Lin
Antibiotics 2024, 13(11), 1099; https://doi.org/10.3390/antibiotics13111099 - 19 Nov 2024
Viewed by 467
Abstract
Backgroud: This prospective randomized trial evaluated the clinical efficacy of inhaled colistin administered through two distinct nebulizer types, a vibrating mesh nebulizer (VMN) and a jet nebulizer (JN), in the treatment of ventilator-associated pneumonia caused by multidrug-resistant bacteria. In addition, an in vitro [...] Read more.
Backgroud: This prospective randomized trial evaluated the clinical efficacy of inhaled colistin administered through two distinct nebulizer types, a vibrating mesh nebulizer (VMN) and a jet nebulizer (JN), in the treatment of ventilator-associated pneumonia caused by multidrug-resistant bacteria. In addition, an in vitro model was used to determine the optimal delivery of colistin. Method: Thirty-two patients prescribed intravenous (IV) colistin inhalation were randomized to receive either a VMN (n = 17) or a JN (n = 15), then compared to the control group (IV alone) over a 7-to 10-day period. The primary endpoint was the clinical pulmonary infection score (CPIS), and the secondary endpoints were the Sequential Organ Failure Assessment (SOFA) score, Acute Physiology and Chronic Health Evaluation (APACE) score, and duration of ventilator use. Results: Results from in vitro testing demonstrated that VMN delivered a significantly higher colistin dose than JN (35.68 ± 3.55% vs. 23.56 ± 3.31%; p < 0.001) when positioned at the humidifier inlet. Compared to the IV alone group, the IV with inhalation group yielded significant improvements in CPIS, SOFA score, and APACHE score on day 7; nevertheless, clinical outcomes between the two nebulizers were statistically indistinguishable. Conclusions: In conclusion, although VMN delivers a higher dose in vitro, both nebulizers yielded comparable clinical outcomes. This study was registered at US Clinical Trial Registration (NCT04633317). Full article
(This article belongs to the Section Antibiotic Therapy in Infectious Diseases)
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<p>The study flow diagram.</p>
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<p>Trends in blood urea nitrogen (BUN) and creatinine levels for nephrotoxicity monitoring. Data are presented as mean. Comparisons among three groups at five time points were analyzed by Freidman test, * <span class="html-italic">p</span> &lt; 0.05; comparisons among three groups were analyzed by Kruskal–Wallis test. Abbreviations: IV, intravenous; JN, jet nebulizer; VMN, vibrating mesh nebulizer.</p>
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<p>Comparisons of drug dose (% ±SD, (<b>A</b>)) collected distal to the endotracheal tube and time (<b>B</b>) of delivery using two nebulizers placed at the inlet of the humidifier and between the inspiratory limb and circuit Y.</p>
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15 pages, 7465 KiB  
Article
Development of a Real-Time PCR Assay for the Detection of Francisella spp. and the Identification of F. tularensis subsp. mediasiatica
by Alexandr Shevtsov, Ayan Dauletov, Uinkul Izbanova, Alma Kairzhanova, Nailya Tursunbay, Vladimir Kiyan and Gilles Vergnaud
Microorganisms 2024, 12(11), 2345; https://doi.org/10.3390/microorganisms12112345 - 16 Nov 2024
Viewed by 483
Abstract
Tularemia is an acute infectious disease classified as a natural focal infection, requiring continuous monitoring of both human and animal morbidity, as well as tracking of pathogen circulation in natural reservoirs and vectors. These efforts are essential for a comprehensive prevention and containment [...] Read more.
Tularemia is an acute infectious disease classified as a natural focal infection, requiring continuous monitoring of both human and animal morbidity, as well as tracking of pathogen circulation in natural reservoirs and vectors. These efforts are essential for a comprehensive prevention and containment strategy. The causative agent, Francisella tularensis, comprises three subspecies—tularensis, holarctica, and mediasiatica—which differ in their geographic distribution and virulence. The ability to directly detect the pathogen and differentiate between subspecies has enhanced diagnostics and allowed a more accurate identification of circulation areas. Real-time PCR protocols for identification of F. tularensis subspecies tularensis and holarctica have been developed, utilizing specific primers and probes that target unique genomic regions. In this study, we present the development of a new real-time PCR assay for the detection of Francisella spp. and differentiation of F. tularensis subsp. mediasiatica. The specificity of the assay was tested on DNA from 86 bacterial species across 31 families unrelated to Francisella spp., as well as on DNA collections of F. tularensis subsp. mediasiatica and F. tularensis subsp. holarctica. The limit of detection (LOD95%) for real-time PCR in detecting Francisella spp. was 0.297 fg (0.145 genomic equivalents, GE) for holarctica DNA and 0.733 fg (0.358 GE) for mediasiatica DNA. The LOD95% for subspecies differential identification of mediasiatica was 8.156 fg (3.979, GE). The high sensitivity and specificity of these developed protocols enable direct detection of pathogens in biological and environmental samples, thereby improving the efficiency of tularemia surveillance in Kazakhstan. Full article
(This article belongs to the Section Molecular Microbiology and Immunology)
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<p>Primers design for identification of <span class="html-italic">F. tularensis</span> subsp. <span class="html-italic">mediasiatica.</span> (<b>A</b>) Aligned genomic fragments of <span class="html-italic">F. novicida</span> and of the three <span class="html-italic">F. tularensis</span> subspecies representatives used for primer selection for the subspecies identification of <span class="html-italic">mediasiatica</span>. (<b>B</b>) The alignment of target fragments from all circular genomes of the <span class="html-italic">F. tularensis</span> subsp. <span class="html-italic">mediasiatica</span> and two sequences from the genomes of the subspecies <span class="html-italic">holarctica</span>, <span class="html-italic">tularensis</span>, and <span class="html-italic">F. novicida</span>.</p>
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<p>Sensitivity testing of real-time PCR for <span class="html-italic">Francisella</span> spp. detection and subspecies differentiation of <span class="html-italic">F. tularensis</span> subsp. <span class="html-italic">mediasiatica</span>. qPCR assays were performed on <span class="html-italic">Francisella</span> spp. samples using 4-fold serial dilutions ranging from 1,000,000 to 0.015 copies. (<b>A</b>) Real-time PCR results for the detection of <span class="html-italic">Francisella</span> spp. using <span class="html-italic">F. tularensis</span> subsp. <span class="html-italic">holarctica</span> DNA (Primers/TaqMan: isftu-2_F_242, isftu-2_R_396 and isftu-2_Probes_331). (<b>B</b>) Real-time PCR results for the detection of <span class="html-italic">Francisella</span> spp. using <span class="html-italic">F. tularensis</span> subsp. <span class="html-italic">mediasiatica</span> DNA (Primers/TaqMan: isftu-2_F_242, isftu-2_R_396 and isftu-2_Probes_331). (<b>C</b>) Real-time PCR results for the subspecies differentiation of <span class="html-italic">F. tularensis</span> subsp. <span class="html-italic">mediasiatica</span> (Primers/TaqMan: FtM_452000_F, FtM_452000_R and FtM_452000_probe). Each sample was tested in triplicate. The horizontal red line indicates the fluorescence threshold.</p>
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<p>Standard curves were generated for three independent real-time PCR reactions: (<b>A</b>) species identification using <span class="html-italic">Francisella tularensis</span> subsp. <span class="html-italic">holarctica</span> samples, (<b>B</b>) species identification using <span class="html-italic">F. tularensis</span> subsp. <span class="html-italic">mediasiatica</span> samples, and (<b>C</b>) subspecies identification of <span class="html-italic">F. tularensis</span> subsp. <span class="html-italic">mediasiatica</span>. For each reaction, 16-fold serial dilutions of the samples were performed, starting with concentrations of 2.05 ng (1,000,000 genome equivalents, GE), 0.12 ng (62,500 GE), 8 pg (3906 GE), 0.5 pg (244 GE), 31.2 fg (15.2 GE), and 1.95 fg (0.95 GE).</p>
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