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    Neisseria and Moraxella - HANDOUTS

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    eula
    This document discusses the classification, identification and diagnostic testing of Neisseria gonorrhoeae, Neisseria meningitidis, and Moraxella catarrhalis. It describes the morphology, growth characteristics, and biochemical reactions used to identify these important pathogens. N. gonorrhoeae and N. meningitidis are aerobic, gram-negative diplococci that can be identified using tests for oxidase, catalase and carbohydrate utilization patterns. Culture methods and selective media are outlined for laboratory diagnosis of infections caused by these organisms.

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    Neisseria and Moraxella - HANDOUTS

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    eula
    64 views10 pages
    This document discusses the classification, identification and diagnostic testing of Neisseria gonorrhoeae, Neisseria meningitidis, and Moraxella catarrhalis. It describes the morphology, growth characteristics, and biochemical reactions used to identify these important pathogens. N. gonorrhoeae and N. meningitidis are aerobic, gram-negative diplococci that can be identified using tests for oxidase, catalase and carbohydrate utilization patterns. Culture methods and selective media are outlined for laboratory diagnosis of infections caused by these organisms.

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    Neisseria and Moraxella.HANDOUTS

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    This document discusses the classification, identification and diagnostic testing of Neisseria gonorrhoeae, Neisseria meningitidis, and Moraxella catarrhalis. It describes the morphology, growth characteristics, and biochemical reactions used to identify these important pathogens. N. gonorrhoeae and N. meningitidis are aerobic, gram-negative diplococci that can be identified using tests for oxidase, catalase and carbohydrate utilization patterns. Culture methods and selective media are outlined for laboratory diagnosis of infections caused by these organisms.

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    © All Rights Reserved
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    Download as docx, pdf, or txt
    64 views10 pages

    Neisseria and Moraxella - HANDOUTS

    Uploaded by

    eula
    This document discusses the classification, identification and diagnostic testing of Neisseria gonorrhoeae, Neisseria meningitidis, and Moraxella catarrhalis. It describes the morphology, growth characteristics, and biochemical reactions used to identify these important pathogens. N. gonorrhoeae and N. meningitidis are aerobic, gram-negative diplococci that can be identified using tests for oxidase, catalase and carbohydrate utilization patterns. Culture methods and selective media are outlined for laboratory diagnosis of infections caused by these organisms.

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    of 10

    • Neisseria and

    Moraxella
    • OUR LADY OF FATIMA UNIVERSITY – ANTIPOLO
    CAMPUS
    • COLLEGE OF MEDICAL LABORATORY SCIENCE
    • CLINICAL BACTERIOLOGY 211
    • TAMARA MARIA B. PASCUAL, RMT
    •General Characteristics –
    Neisseria spp.
    • Most Neisseria spp. are aerobic, nonmotile, non–
    spore-forming, gram-negative diplococci
     Except Neisseria elongata, Neisseria weaveri, and
    Neisseria bacilliformis – rod-shaped
    • Oxidase positive
    • Catalase positive (except N. elongata and N.
    bacilliformis)
    • Many Neisseria spp. are capnophilic and have
    optimal growth in a humid atmosphere
    • They can grow anaerobically if alternative electron
    acceptors (e.g., nitrites) are available
    • Natural habitat - mucous membranes of the
    respiratory and urogenital tracts

    • Important species of the genus


    Neisseria are:
    • N. meningitidis,
    • N. gonorrhoeae,
    • N. flavescens,
    • N. subflava,
    • N. sicca,
    • N. mucosa,
    • N. lactamica
    • N. polysacchareae
    • N. gonorrhoeae and N. meningitidis are
    the primary human pathogens of the
    genus.
    • Neisseria gonorrhoeae

    • Gonococcus
    •Neisseria gonorrhoeae
    • Neisseria gonorrhoeae – Clinical
    Infections
    • Neisseria gonorrhoeae –
    Epidemiology
    • Neisseria gonorrhoeae – Epidemiology

    • A non-venereal infection is ophthalmia


    neonatorum in the newborn (gonococcal
    eye infection)
     The eyes are coated with gonococci as the
    baby passes down the birth canal
     Can result in blindness if not treated
    immediately
    • Neisseria gonorrhoeae – Laboratory Diagnosis

    •Neisseria gonorrhoeae –
    Laboratory Diagnosis
    B. Direct Microscopic Examination
     Gram-negative intracellular diplococci
     The gonococci are in pairs with adjacent sides
    flattened, giving them a kidney shape
     Gram stain with more than five
    polymorphonuclear neutrophils per field but no
    bacteria – nongonococcal urethritis with
    organisms such as Chlamydia trachomatis or
    Ureaplasma urealyticum

    •Neisseria gonorrhoeae –
    Laboratory Diagnosis
    C. Culture
     Does not grow on SBA
     Medium of choice – CAP
     Selective medium:
    • Thayer-Martin
    • Modified Thayer-Martin
    • Martin-Lewis
    • New York City
    • GC-LECT
     Inhibitory agents – vancomycin and
    colistin – inhibit gram-positive bacteria,
    gram-negative bacteria and fungi;
    trimethoprim – inhibit Proteus spp.
     All specimens received in the laboratory for
    recovery of Neisseria spp. should be held at
    room temperature and plated as soon as
    possible
     Neisseria spp. are susceptible to cold – media
    should be warmed to room temperature before
    inoculation

    • Neisseria gonorrhoeae – Laboratory


    Diagnosis
    D. Incubation
    • Inoculated plates should be incubated at 35° C
    in a 3% to 5% CO2 atmosphere
    • Incubation is accomplished by use of a CO2
    incubator, CO2 generating pouch, or a candle
    extinction jar (white wax candles only)

    •Neisseria gonorrhoeae –
    Laboratory Diagnosis
    E. Laboratory Identification
     CAP or Selective Agar colony morphology – small,
    gray to tan, translucent, and raised after 24-48 hours of
    incubation
     Oxidase Test – positive (purple color)
     Carbohydrate Utilization – traditional method for
    the identification of Neisseria spp.
     Medium used – CTA (Cystine Trypticase Agar) –
    containing 1% the individual carbohydrate and
    phenol red (pH indicator)
     If the organism uses the particular carbohydrate –
    acid production (yellow color)
     N. gonorrhoeae is glucose fermenter only
     Genetic Probes – probes specific for the nucleic acids
    of N. gonorrhoeae have been developed for the direct
    detection of bacteria in clinical specimens

    •Neisseria gonorrhoeae -
    Treatment
    • Neisseria meningitidis

    • Meningococcus, Diplococcus
    Intracellularis Meningitidis
    • Neisseria meningitidis – Epidemiology

    •Neisseria meningitidis – Clinical


    Infections
    • Meningococcemia
    • Purpura (hemorrhaging of blood into the skin and
    mucous membranes producing bruises) with
    petechial skin rash (pinpoint red spot caused by
    hemorrhage)
    • Tachycardia
    • Hypotension
    • Thrombosis
    • In some cases, the disease becomes fulminant and
    spreads rapidly, causing:
     Disseminated intravascular coagulation,
     Septic shock
     Hemorrhage in the adrenal glands (Waterhouse-
    Friderichsen syndrome)
    •Meningitis
    • Neisseria meningitidis – Laboratory Diagnosis

    •Neisseria meningitidis –
    Laboratory Diagnosis
    B. Direct Microscopic Examination
    • Appear as intracellular and extracellular
    gram-negative diplococci (with adjacent
    sides flattened)
    C. Culture and Incubation
    • Can grow on SBA and CAP
    • Same atmospheric conditions with N.
    gonorrhoeae
    •Neisseria meningitidis –
    Laboratory Diagnosis
    D. Laboratory Identification
    • CAP and SBA colony morphology – medium-sized,
    gray, and convex, and encapsulated strains are mucoid
    strains are mucoid
     Blood agar underneath – colonies tends to have a
    green tinge
    • Oxidase positive
    • Catalase positive
    • Glucose and maltose fermenter
    • Gamma-glutamyl aminopeptidase positive (negative for
    N. gonorrhoeae, N. lactamica, and M. catarrhalis)
    • Neisseria meningitidis – Treatment
    • Moraxella catarrhalis
    • Moraxella catarrhalis

    •Moraxella catarrhalis –
    Laboratory Diagnosis
    A. Specimen Collection and Identification
    • Middle ear effusion, nasopharynx, sinus
    aspirates, sputum aspirates, or bronchial
    aspirates
    • SBA and CAP colony morphology - smooth,
    opaque, gray-to-white colonies “hockey puck” –
    colony remains intact when pushed across the
    plate with a loop
     Older colonies – “wagon-wheel” appearance
    • Most strains can tolerate lower temperature and
    grow well at 28° C
    • Inhibited by colistin on gonococcal selective
    agars

    •Moraxella catarrhalis –
    Laboratory Diagnosis
    • Commensal Neisseria species

    • N. cinerea – misidentified as N.
    gonorrhoeae
     Non-glucose fermenter
     Grows on SBA
     Susceptible to colistin
    • N. flavescens –yellow-pigmented
    Neisseria species that is asaccharolytic
    • N. mucosa – large, very mucoid
    colonies (often adhere to the agar)
    • N. lactamica – glucose, maltose and
    lactose fermenter
     Misidentified as N. meningitidis
    (glucose and maltose fermenter only)

    • N. polysaccharea – produces large


    amounts of extracellular polysaccharide
    when grown in media containing 1% or
    5% sucrose
    • N. sicca – dry, wrinkled, adherent, and
    breadcrumb-like colonies
    • N. subflava – “less yellow”
    • N. elongata, N. weaveri, N.
    bacilliformis – rod-shaped

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