Urinary Tract Infections and Asymptomatic Bacteriuria in Pregnancy
Urinary Tract Infections and Asymptomatic Bacteriuria in Pregnancy
Urinary Tract Infections and Asymptomatic Bacteriuria in Pregnancy
Authors
Thomas M Hooton, MD
Kalpana Gupta, MD, MPH
Section Editors
Stephen B Calderwood, MD
Charles J Lockwood, MD, MHCM
Deputy Editor
Allyson Bloom, MD
All topics are updated as new evidence becomes available and our peer
review process is complete.
Literature review current through: Jan 2015. | This topic last
updated: Jan 23, 2015.
however the optimal target populations for this is uncertain. (See "Initial
prenatal assessment and first trimester prenatal care".)
Specimen collection The diagnosis of asymptomatic bacteriuria should be
based on culture of a urine specimen collected in a manner that minimizes
contamination. Although the optimal method for collecting voided urine is
uncertain, instructing women to spread their labia and collect a midstream
urine (without requiring a clean-catch) seems most reasonable. Routine
catheterization to screen for bacteriuria is not warranted due to the risk of
introducing infection. (See "Sampling and evaluation of voided urine in the
diagnosis of urinary tract infection in adults".)
In order to minimize contamination of the voided specimen, it is often
recommended that the patient collect a clean-catch (after local cleansing of
the urethral meatus and surrounding mucosa) midstream (collection of the
second portion of the voided urine after discarding the initial stream)
specimen. However, it is not clear that these measures reduce
contamination. In a study of 113 asymptomatic pregnant women, each was
instructed to collect a midstream sample from the first concentrated
morning urine, a midstream sample, and a clean-catch midstream sample,
in that order, over the course of a day [ 28]. Rates of mixed growth and
growth of skin flora on culture in midstream urine were comparable with
those observed in the morning and clean-catch samples. Overall rates of
contamination were high in all three samples, and the women were tested
at a mean of 32 weeks of gestation as opposed to the recommended period
of 16 weeks. Findings from this and other studies suggest that collection of
a clean-catch voided urine specimen is of little value [ 29,30].
Proper handling and processing of the specimen is crucial to avoid falsepositive results. (See "Microbiology specimen collection and transport".)
Diagnostic criteria For asymptomatic women, bacteriuria is formally
defined as two consecutive voided urine specimens with isolation of the
same bacterial strain in quantitative counts of 10 5 colony forming
units (cfu)/mL or a single catheterized urine specimen with one bacterial
species isolated in a quantitative count of 10 2 cfu/mL [2]. In clinical
practice, however, only one voided urine specimen is typically obtained,
and diagnosis (and treatment initiation) is made in women with
105 cfu/mL without obtaining a confirmatory repeat culture. If bacteria that
are not typical uropathogens (such as lactobacillus) are isolated, treatment
reading level, and they answer the four or five key questions a patient
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Beyond the Basics patient education pieces are longer, more sophisticated,
and more detailed. These articles are written at the 10 th to 12th grade
reading level and are best for patients who want in-depth information and
are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We
encourage you to print or e-mail these topics to your patients. (You can also
locate patient education articles on a variety of subjects by searching on
"patient info" and the keyword(s) of interest.)
Beyond the Basics topics (see "Patient information: Urinary tract infections
in adolescents and adults (Beyond the Basics)")
SUMMARY AND RECOMMENDATIONS
Bacteriuria occurs commonly in pregnancy, typically during early
pregnancy. Without treatment, as many as 30 to 40 percent of pregnant
women with asymptomatic bacteriuria will develop a symptomatic urinary
tract infection (UTI). The smooth muscle relaxation and subsequent ureteral
dilatation that occurs in pregnancy are thought to facilitate the ascent of
bacteria from the bladder to the kidney, accounting for the greater risk of
pyelonephritis. Additionally, untreated bacteriuria is associated with an
increased risk of preterm birth, low birth weight, and perinatal mortality.
(See 'Epidemiology' above and 'Pathogenesis' above.)
As in nonpregnant women, Escherichia coli is the predominant
uropathogen found in both asymptomatic bacteriuria and UTI in pregnant
women. (See 'Microbiology' above.)
We screen all pregnant women at least once for asymptomatic bacteriuria.
Screening for asymptomatic bacteriuria is performed at 12 to 16 weeks
gestation with a midstream urine for culture. The diagnosis is made by
finding high-level bacterial growth (10 5 colony forming units [cfu]/mL) on
urine culture in the absence of symptoms consistent with UTI. (See
'Diagnosis' above.)
Patterson TF, Andriole VT. Detection, significance, and therapy of bacteriuria in pregnancy.
Update in the managed health care era. Infect Dis Clin North Am 1997; 11:593.
Nicolle LE, Bradley S, Colgan R, et al. Infectious Diseases Society of America guidelines for
the diagnosis and treatment of asymptomatic bacteriuria in adults. Clin Infect Dis 2005;
40:643.
Sobel JD and Kaye D. Urinary tract infections. In: Mandell, Douglas, and Bennett's Principles
and practice of infectious diseases, 7, Mandell GL, Bennett JE, and Dolin R. (Eds), Elsevier,
Philadelphia 2010. Vol 1, p.957.
Alvarez JR, Fechner AJ, Williams SF, et al. Asymptomatic bacteriuria in pregestational diabetic
pregnancies and the role of group B streptococcus. Am J Perinatol 2010; 27:231.
Gilstrap LC 3rd, Ramin SM. Urinary tract infections during pregnancy. Obstet Gynecol Clin
North Am 2001; 28:581.
Harris RE, Gilstrap LC 3rd. Cystitis during pregnancy: a distinct clinical entity. Obstet Gynecol
1981; 57:578.
10
Hill JB, Sheffield JS, McIntire DD, Wendel GD Jr. Acute pyelonephritis in pregnancy. Obstet
Gynecol 2005; 105:18.
11
12
Thurman AR, Steed LL, Hulsey T, Soper DE. Bacteriuria in pregnant women with sickle cell
trait. Am J Obstet Gynecol 2006; 194:1366.
13 KASS EH. Bacteriuria and pyelonephritis of pregnancy. Arch Intern Med 1960; 105:194.
14
Naeye RL. Causes of the excessive rates of perinatal mortality and prematurity in
pregnancies complicated by maternal urinary-tract infections. N Engl J Med 1979; 300:819.
15
Millar LK, Cox SM. Urinary tract infections complicating pregnancy. Infect Dis Clin North Am
1997; 11:13.
16
Delzell JE Jr, Lefevre ML. Urinary tract infections during pregnancy. Am Fam Physician 2000;
61:713.
17 Millar LK, DeBuque L, Wing DA. Uterine contraction frequency during treatment of
pyelonephritis in pregnancy and subsequent risk of preterm birth. J Perinat Med 2003;
31:41.
Romero R, Oyarzun E, Mazor M, et al. Meta-analysis of the relationship between
18 asymptomatic bacteriuria and preterm delivery/low birth weight. Obstet Gynecol 1989;
73:576.
19
Minassian C, Thomas SL, Williams DJ, et al. Acute maternal infection and risk of preeclampsia: a population-based case-control study. PLoS One 2013; 8:e73047.
20
Archabald KL, Friedman A, Raker CA, Anderson BL. Impact of trimester on morbidity of acute
pyelonephritis in pregnancy. Am J Obstet Gynecol 2009; 201:406.e1.
21
22 Sweet RL. Bacteriuria and pyelonephritis during pregnancy. Semin Perinatol 1977; 1:25.
23
Schito GC, Naber KG, Botto H, et al. The ARESC study: an international survey on the
24 antimicrobial resistance of pathogens involved in uncomplicated urinary tract infections. Int J
Antimicrob Agents 2009; 34:407.
Ho PL, Yip KS, Chow KH, et al. Antimicrobial resistance among uropathogens that cause
25 acute uncomplicated cystitis in women in Hong Kong: a prospective multicenter study in
2006 to 2008. Diagn Microbiol Infect Dis 2010; 66:87.
Pathak A, Chandran SP, Mahadik K, et al. Frequency and factors associated with carriage of
26 multi-drug resistant commensal Escherichia coli among women attending antenatal clinics in
central India. BMC Infect Dis 2013; 13:199.
Lin K, Fajardo K, U.S. Preventive Services Task Force. Screening for asymptomatic bacteriuria
27 in adults: evidence for the U.S. Preventive Services Task Force reaffirmation recommendation
statement. Ann Intern Med 2008; 149:W20.
28
Schneeberger C, van den Heuvel ER, Erwich JJ, et al. Contamination rates of three urinesampling methods to assess bacteriuria in pregnant women. Obstet Gynecol 2013; 121:299.
29
30
Lifshitz E, Kramer L. Outpatient urine culture: does collection technique matter? Arch Intern
Med 2000; 160:2537.
31
Millar L, DeBuque L, Leialoha C, et al. Rapid enzymatic urine screening test to detect
bacteriuria in pregnancy. Obstet Gynecol 2000; 95:601.
McNair RD, MacDonald SR, Dooley SL, Peterson LR. Evaluation of the centrifuged and Gram32 stained smear, urinalysis, and reagent strip testing to detect asymptomatic bacteriuria in
obstetric patients. Am J Obstet Gynecol 2000; 182:1076.
33
Shelton SD, Boggess KA, Kirvan K, et al. Urinary interleukin-8 with asymptomatic bacteriuria
in pregnancy. Obstet Gynecol 2001; 97:583.
Rouse DJ, Andrews WW, Goldenberg RL, Owen J. Screening and treatment of asymptomatic
34 bacteriuria of pregnancy to prevent pyelonephritis: a cost-effectiveness and cost-benefit
analysis. Obstet Gynecol 1995; 86:119.
35
Mittendorf R, Williams MA, Kass EH. Prevention of preterm delivery and low birth weight
associated with asymptomatic bacteriuria. Clin Infect Dis 1992; 14:927.
36
Gratacs E, Torres PJ, Vila J, et al. Screening and treatment of asymptomatic bacteriuria in
pregnancy prevent pyelonephritis. J Infect Dis 1994; 169:1390.
38
Zinner SH, Kass EH. Long-term (10 to 14 years) follow-up of bacteriuria of pregnancy. N Engl
J Med 1971; 285:820.
39 Tan JS, File TM Jr. Treatment of bacteriuria in pregnancy. Drugs 1992; 44:972.
40
Vercaigne LM, Zhanel GG. Recommended treatment for urinary tract infection in pregnancy.
Ann Pharmacother 1994; 28:248.
41
42
43
Reeves DS. Treatment of bacteriuria in pregnancy with single dose fosfomycin trometamol: a
review. Infection 1992; 20 Suppl 4:S313.
44
45
Stamm WE, Counts GW, Running KR, et al. Diagnosis of coliform infection in acutely dysuric
women. N Engl J Med 1982; 307:463.
46
Hooton TM, Roberts PL, Cox ME, Stapleton AE. Voided midstream urine culture and acute
cystitis in premenopausal women. N Engl J Med 2013; 369:1883.
47
Kunin CM, White LV, Hua TH. A reassessment of the importance of "low-count" bacteriuria in
young women with acute urinary symptoms. Ann Intern Med 1993; 119:454.
Gupta K, Hooton TM, Naber KG, et al. International clinical practice guidelines for the
treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by
48
the Infectious Diseases Society of America and the European Society for Microbiology and
Infectious Diseases. Clin Infect Dis 2011; 52:e103.
49
Vazquez JC, Abalos E. Treatments for symptomatic urinary tract infections during pregnancy.
Cochrane Database Syst Rev 2011; :CD002256.
50
Rodrguez-Bao J, Alcal JC, Cisneros JM, et al. Community infections caused by extendedspectrum beta-lactamase-producing Escherichia coli. Arch Intern Med 2008; 168:1897.
51
Lutters M, Vogt-Ferrier NB. Antibiotic duration for treating uncomplicated, symptomatic lower
urinary tract infections in elderly women. Cochrane Database Syst Rev 2008; :CD001535.
52
Cunningham FG, Lucas MJ. Urinary tract infections complicating pregnancy. Baillieres Clin
Obstet Gynaecol 1994; 8:353.
53
Cunningham FG, Lucas MJ, Hankins GD. Pulmonary injury complicating antepartum
pyelonephritis. Am J Obstet Gynecol 1987; 156:797.
54
Towers CV, Kaminskas CM, Garite TJ, et al. Pulmonary injury associated with antepartum
pyelonephritis: can patients at risk be identified? Am J Obstet Gynecol 1991; 164:974.
55
Cox SM, Shelburne P, Mason R, et al. Mechanisms of hemolysis and anemia associated with
acute antepartum pyelonephritis. Am J Obstet Gynecol 1991; 164:587.
56
Wing DA, Park AS, Debuque L, Millar LK. Limited clinical utility of blood and urine cultures in
57 the treatment of acute pyelonephritis during pregnancy. Am J Obstet Gynecol 2000;
182:1437.
58
59
Millar LK, Wing DA, Paul RH, Grimes DA. Outpatient treatment of pyelonephritis in
pregnancy: a randomized controlled trial. Obstet Gynecol 1995; 86:560.
60
of
acute
61
Wing DA, Hendershott CM, Debuque L, Millar LK. A randomized trial of three antibiotic
regimens for the treatment of pyelonephritis in pregnancy. Obstet Gynecol 1998; 92:249.
Naber KG, Schito G, Botto H, et al. Surveillance study in Europe and Brazil on clinical aspects
64 and Antimicrobial Resistance Epidemiology in Females with Cystitis (ARESC): implications for
empiric therapy. Eur Urol 2008; 54:1164.
Zhanel GG, Hisanaga TL, Laing NM, et al. Antibiotic resistance in Escherichia coli outpatient
65 urinary isolates: final results from the North American Urinary Tract Infection Collaborative
Alliance (NAUTICA). Int J Antimicrob Agents 2006; 27:468.
Warren JW, Abrutyn E, Hebel JR, et al. Guidelines for antimicrobial treatment of
66 uncomplicated acute bacterial cystitis and acute pyelonephritis in women. Infectious Diseases
Society of America (IDSA). Clin Infect Dis 1999; 29:745.
Lenke RR, VanDorsten JP, Schifrin BS. Pyelonephritis in pregnancy: a prospective randomized
67 trial to prevent recurrent disease evaluating suppressive therapy with nitrofurantoin and
close surveillance. Am J Obstet Gynecol 1983; 146:953.
68
Harris RE, Gilstrap LC 3rd. Prevention of recurrent pyelonephritis during pregnancy. Obstet
Gynecol 1974; 44:637.
69
70
Pfau A, Sacks TG. Effective prophylaxis for recurrent urinary tract infections during
pregnancy. Clin Infect Dis 1992; 14:810.
Keating GM. Fosfomycin trometamol: a review of its use as a single-dose oral treatment for
71 patients with acute lower urinary tract infections and pregnant women with asymptomatic
bacteriuria. Drugs 2013; 73:1951.
Crider KS, Cleves MA, Reefhuis J, et al. Antibacterial medication use during pregnancy and
72 risk of birth defects: National Birth Defects Prevention Study. Arch Pediatr Adolesc Med 2009;
163:978.
73
Ben David S, Einarson T, Ben David Y, et al. The safety of nitrofurantoin during the first
trimester of pregnancy: meta-analysis. Fundam Clin Pharmacol 1995; 9:503.
74
Le J, Briggs GG, McKeown A, Bustillo G. Urinary tract infections during pregnancy. Ann
Pharmacother 2004; 38:1692.
Disclosures
Disclosures: Thomas M Hooton, MD Consultant/Advisory Boards: Cubist
[Complicated UTI (Ceftolozane/tazobactam)]; Vifor Pharma [Uncomplicated UTI
(Immunostimulant uro-vaxom)]. Equity Ownership/Stock Options: Fimbrion
Therapeutics [Prevention of UTI (Developing mannosides that may eventually be
useful in prevention of UTI)]. Kalpana Gupta, MD, MPH Consultant/Advisory Boards:
Boehringer Ingelheim GmbH [UTI (Empagliflozin)]; Paratek [UTI (Omadacycline)];