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[8] LABORATORY DIAGNOSIS > Neisseriaceae and Moraxella catarrhalis > Flashcards

Neisseriaceae and Moraxella catarrhalis Flashcards

1
Q

For detection of Neisseria gonorrhoeae:

Pus/secretions from:

A
  • Genital sites (male urethra, female cervix, or vagina in prepubertal girls)
  • Extragenital sites (conjunctiva, throat, rectum)
  • Blood, synovial fluid, or joint fluid in systemic illness
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2
Q

For detection of Neisseria meningitidis:

A
  • Blood
  • CSF
  • Puncture material from petechiae
  • Nasopharyngeal swab for carrier surveys
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3
Q

Direct inoculation of blood culture bottles is preferred over SPS Vacutainer tubes owing to the recognized [?] of SPS on gonococci or meningococci.

If blood is first collected in Vacutainer
tubes containing SPS, the specimen must be transferred to the broth culture system within 1 hour of collection.

A

inhibitory effects

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4
Q

Should be inoculated into aerobic blood culture bottles.

A

Joint /synovial fluids

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5
Q

Any specimens or cultures in which N. meningitidis is a consideration should be handled in a [?] to prevent laboratory-acquired infections.

A

biologic safety cabinet

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6
Q

of the specimen reveals gram-negative kidney or coffee-bean-shaped diplococci found intracellularly within polymorphonuclear leukocytes (PMNs) or extracellularly.

A

Direct gram-stained smear

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7
Q

Diagnostic of gonococcal infection with sensitivity of about 90% and a specificity of 99%.

A

In urethral specimen from males

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8
Q

Only presumptive evidence of gonococcal infection, because the normal vaginal and rectal flora are composed of gram-negative coccobacilli, which can resemble Neisseria spp. Diagnosis must be confirmed by culture and additional testing.

A

In endocervical specimen in females or in rectal specimen

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9
Q

Can also be diagnostic

A

In conjunctival exudates

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10
Q

NOT diagnostic of gonococcal infection, because nonpathogenic, commensal Neisseria spp. may be present. Diagnosis must be confirmed by culture and additional testing.

A

In pharyngeal specimens

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11
Q

Direct gram-stained smear of [?] or other specimen reveals gram-negative kidney or coffeebean-shaped diplococci found intracellularly within polymorphonuclear leukocytes (PMNs) or extracellularly.

A

blood, CSF

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12
Q

Heavily encapsulated strains may have a [?] around the cells.

A

distinct pink halo

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13
Q

A [?] is a critical result that must be reported to the requesting physician immediately.

A

positive blood or CSF gram stain

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14
Q

Is preferred over BAM for isolation because heating the blood to 80 oC inactivates fatty acids and trace metals in blood which are inhibitory to the pathogenic Neisseria.

A

Chocolate agar medium

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15
Q

Contain antimicrobial agents that inhibit other microorganisms and allow the selective recovery of pathogenic N. gonorrhoeae and N. meningitidis

A

Selective Media

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16
Q

very rarely causes disease but is important because it grows in the selective media used for cultures of gonococci and meningococci from clinical specimens.

A

N. lactamica

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17
Q

N .lactamica can be cultured from the [?] of 3–40% of persons and most often is found in children.

A

nasopharynx

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18
Q

Enriched chocolate agar-based media that are prepared with nitrogenous GC agar base, hemoglobin , and enrichment

A

Thayer-Martin (TM), Modified Thayer Martin (MTM), Martin-Lewis (ML), and GC-Lect

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19
Q

chemically defined supplement that

provide vitamins, amino acids cystine and cysteine), coenzymes, dextrose, ferric ions and other factors

A

IsoVitaleX

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20
Q

A clear peptone-corn starch agar-based medium containing yeast dialysate, citrated horse plasma, and lysed horse erythrocytes.

A

New York City (NYC) medium

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21
Q

Consists of selective medium (MTM, ML, or GC-Lect) in a self-contained CO2 environment

A

Culture Media Transport System

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22
Q

Intended for transport and primary isolation of pathogenic Neisseria

A

Culture Media Transport System

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23
Q

Agar slant in a bottle has a formulation similar to MTM but has a higher dextrose to promote growth of Neisseria and a high agar to provide a more rigid medium suitable for mailing.

A

Transgrow Medium

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24
Q

Adequate CO2 is incorporated within the media bottle.

A

Transgrow Medium

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25
Q

A tablet consisting of a mixture of citric
acid and sodium bicarbonate is activated by the moisture (humidity) produced by the culture medium within the sealed plastic bag and generates CO2 levels
sufficient for the growth of Neisseria on the selective media provided with the system

A

Gono-Pak

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26
Q

A tablet consisting of a mixture of citric acid and sodium bicarbonate is placed in a well within the plate and is activated by the moisture (humidity) produced by the culture medium within the sealed plastic
bag.

A

JEMBEC (John E. Martin Biological Environmental Chamber)

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27
Q

The CO2 levels generated are sufficient for the growth of Neisseria on the selective media provided with the system.

A

JEMBEC (John E. Martin Biological Environmental Chamber)

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28
Q

Specimen from sterile sites (blood, CSF, conjunctiva)

A

Inoculate on nonselective CAM and sheep BAM.

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29
Q

Specimen from sterile sites (urethra, cervix, vagina, rectum, pharynx)

A

Inoculate onto both selective (e.g., MTM, ML, NYC, or GC–Lect agar) and nonselective media.

30
Q

Various selective media may fail to support growth due to the susceptibility of some strains to [?], that is why the specimen should also be inoculated onto nonselective medium.

A

vancomycin

31
Q

(CO2 incubator or candle extinction jar)

A

5% to 7% CO2 at 35°C

32
Q

If incubating using a candle jar, only [?] should be used because other types may be toxic to N. gonorrhoeae and N. meningitidis.

A

white, unscented candles

33
Q

Incubation: environment condition for Neisseria meningitidis

A

Humid atmosphere

34
Q

Humidity can be provided by placing a

  • [?] in the bottom of a CO2 incubator
  • [?] in the bottom of a candle jar
A

pan with water

sterile gauze pad soaked with sterile water

35
Q

Incubation of [?] before a final report of “no growth” is issued.

A

24, 48, and 72 hours

36
Q

Suspicious colonies are subcultured to [?] for further identification.

A

blood and chocolate agar

37
Q

Colonies are small, grayishwhite, convex, translucent, glistening colonies with either smooth or irregular margins.

A

N. gonorrhoeae

38
Q

N. gonorrhoeae maybe up to 5 different colony types

A

T1 through T5

39
Q

formerly T1 and T2, respectively
Cells possess pili
‣ Predominantly obtained on primary cultures
‣ Colonies tend to be small, glistening, and raised
‣ Organism suspension tend to be smooth and homogeneous

A

P+ and P++ colony types

40
Q

Cells lack pili
‣ Obtained in subcultures
‣ Colonies tend to be larger, flatter, and not glistening
‣ Do not form smooth suspensions

A

P− colony types (T3, T4, and T5)

41
Q

Colonies are larger than gonococcal colonies, usually attaining a diameter of about 1 mm or more after 18 to 24 hours’ incubation.

A

N. meningitidis

42
Q

Colonies are blue-gray, low and convex, with a smooth, moist entire edge and a glistening surface.

A

N. meningitidis

43
Q

On sheep blood agar, colonies are usually gray, and heavily encapsulated strains may be mucoid.

A

N. meningitidis

44
Q

Neisseria species (EXCEPT N. elongata) and M. catarrhalis are

A

catalase-positive

45
Q

Cytochrome Oxidase Test

Microorganisms that possess a cytochrome c oxidase, which acts in the presence of air, oxidize certain aromatic amines to produce [?]. A positive reaction will be indicated by
a color change.

A

colored indophenol compounds

46
Q

ALL Neisseria species and M. catarrhalis species are

A

oxidase-positive

47
Q

Other, unrelated, bacterial species with cytochrome c in the respiratory chain are also oxidase-positive.

A

Pseudomonas aeruginosa
Haemophilus influenzae
Campylobacter
Pasteurella

48
Q

Cytochrome Oxidase Test : Kovac’s oxidase reagent

A

N,N,N,N-tetramethyl-ρ-phenylenediamine dihydrochloride

1% [w/v] aqueous solution

49
Q

Cytochrome Oxidase Test : Results

A

(+) Purple color within 10 seconds (color changes from pink, maroon, dark red, to finally purplish-black)

50
Q

Cytochrome Oxidase Test : Gordon and McLeod’s oxidase reagent

A

Dimethyl-ρ-phenylenediamine monohydrochloride

1% [w/v] aqueous solution

51
Q

Gordon and McLeod’s oxidase reagent: Result

A

(+) Blue color within 10 – 30 minutes

52
Q

Taxo N test

Disk is moistened with water before use.

A

Commercial disks containing 6% p aminodimethylaniline monohydrochloride

53
Q

Taxo N test: Result

A

(+) Red, purple to black color within 10 seconds

54
Q

The disk is applied directly among the colonies on the plate; Colonies are applied to moistened disk.

A

Taxo N disk test

55
Q

Most neisseriae oxidize carbohydrates, producing acid but not [?], and their carbohydrate patterns are a means of distinguishing them.

A

gas

56
Q

Carbohydrate utilization test: Medium

A

Cystine-trypticase agar (CTA) medium containing 1% carbohydrate and a phenol red pH indicator

57
Q

The usual test battery includes:

A 
CTA-glucose
CTA-maltose
CTA-lactose
CTA-sucrose
Carbohydrate-free CTA control
58
Q

CTA media must not be incubated in [?] because carbonic acid formed in the media results in false-positives.

A

high CO2 atmosphere

59
Q

The small amounts of acid produced oxidatively by some strains of Neisseria species may not be detected.

A

Conventional Carbohydrate Utilization Test

60
Q

Carbohydrate utilization patterns are currently determined by inoculating an extremely heavy suspension of the organism to be tested in a small volume of buffered, low- peptone substrate with the appropriate carbohydrate. These methods do not require subculture or growth, and results are available in approximately 4 hours

A

Rapid Carbohydrate Utilization Test

61
Q

For detection of capsular polysaccharides of meningococcal serogroups A, B, C, H, I, K, L, W135, X, Y, Z using known antisera.

A

Serotyping

62
Q

Direct tests for [?] in CSF, serum, and urine are also available.

A

meningococcal capsular antigens

63
Q

• The genera [?] and [?] is included in the same family as Neisseria because of morphological and biochemical similarities.

A

Branhamella and Moraxellla

64
Q

Most of Branhamella and Moraxellla

species are either relatively [?] of humans and other mammals or are saprobes living in soil and water.

A

harmless commensals

65
Q

emerged as a significant opportunists in host with disturbed immune functions

A

Moraxella catarrhalis

66
Q

found in the normal human nasopharynx and can cause purulent disease

A

Moraxella catarrhalis

67
Q

was previously named Branhamella catarrhalis and before that Neisseria catarrhalis.

A

Moraxella catarrhalis

68
Q

It is associated with several clinical syndromes such as meningitis, endocarditis, sinusitis, otitis media, bronchopulmonary (i.e. pneumonia, bronchitis) infections, and neonatal conjunctivitis.

A

Moraxella catarrhalis

69
Q

Individuals that are most susceptible to infections caused by the organism are those adult patients with

A

leukemia, alcoholism, malignancy, diabetes or rheumatoid disease.

70
Q

Moraxella catarrhalis can be differentiated from the neisseriae by its

A
  • lack of carbohydrate fermentation
  • production of DNase
    = butyrate esterase in tributyrin hydrolysis

[8] LABORATORY DIAGNOSIS (5 decks)

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