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GRAM NEGATIVE COCCI AND GRAM NEGATIVE BACILLI > GRAM NEGATIVE COCCI > Flashcards

GRAM NEGATIVE COCCI Flashcards

1
Q

Microscopic appearance of Neisseria

A

Gram-negative diplococci with coffee or kidney bean shaped

Except N. elongata and N. weaver (rod-shaped)

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2
Q

Culture morphology of Neisseria spp.

A

Small, gray-white opaque, convex, and glistening colonies

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3
Q

What medium is the growth of Neisseria best observed?

A

Enriched medium containing blood serum, cholesterol or oleic acid

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4
Q

Most of the colonies of Neisseria are non pigmented except…

A

N. flava
N. flavescens
N. subflava

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5
Q

Biochemical test:

Neisseria spp.

A

Oxidase (+)
Catalase (+) except N. elongata
Carbohydrate fermenters (primarily glucose and maltose)

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6
Q

Oxygen requirement and optimum temperature for growth of Neisseria

A

Facultative anaerobe; Capnophilic (2-8% CO2)
Moist temperature

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7
Q

They are sensitive to drying and extremes of temperature

A

N. gonorrheae
N. meningitidis

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8
Q

Natural habitat of Neisseria

A

Mucous membranes of the respiratory and urogenital tracts

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9
Q

A gram negative intracellular diplococci, kidney or coffee-bean shaped, that is transmitted by sexual contact, or congenital transmission. They are found in the urogenital tract, anorectal area, oropharynx, and conjunctiva. It is not part of the normal flora and man is the only known host.

A

Neisseria gonorrheae

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10
Q

Leading cause of sexually transmitted disease

A

Neisseria gonorrheae

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11
Q

Culture morphology Neisseria gonorrheae

A

Small, tan, translucent and raised after 24-48 hours of incubation (CAP)

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12
Q

The primary reason for their strict pathogenicity to humans is their ability to bind to transferrin

A

Neisseria gonorrheae

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13
Q

Principal virulence factor of Neisseria gonorrheae

A

Common pili

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14
Q

Produces IgA protease which is important in its pathogenesis (IgA is an antibody found in mucous membrane secretions)

A

Neisseria gonorrheae
Neisseria meningitidis

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15
Q

Virulent colonial type of Neisseria gonorrheae

A

T1 and T2

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16
Q

Avirulent colonial type of Neisseria gonorrheae

A

T3 to T5

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17
Q

Virulence factors of Neisseria gonorrheae

A

Common pili
Receptors for transferring
Capsule
IgA
Cellular membrane proteins (Por B)
Lipooligosaccharide (LOS) endotoxin

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18
Q

Rare isolates of Neisseria gonorrheae isolated from asymptomatic men
Susceptible to penicillin
More fastidious
Smaller in size

A

Auxotypes (AHU strains: arginine, hypoxanthine, and uracil)

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19
Q

Causative agent of the following clinical infections:

Gonorrhea
Purulent urethritis (males)
Cervicitis (females)
Pharyngitis
Anorectal infections
Conjunctivitis
Purulent arthritis

A

Neisseria gonorrheae

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20
Q

Meaning “flow of seed” and “brothel”, is an acute pyogenic infection of non-ciliated columnar and transitional epithelium with a short incubation period of 2-7 days; patients may be asymptomatic

Symptoms: purulent discharge, lower abdominal pain and dysuria (men); dysuria and vaginal bleeding (women)

What is the infection and its causative agent?

A

Gonorrhea caused by Neisseria gonorrheae

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21
Q

Bacteria responsible for sterility and perihepatitis (Fitz-Hugh-Curtis syndrome)

A

Neisseria gonorrheae

This syndrome occurs when gonococcal cervicitis is left untreated

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22
Q

Causative agent of ophthalmia noenetorum, an eye infection acquired during vaginal delivery through an infected birth canal

A

Neisseria gonorrheae

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23
Q

A gonococcal eye infection acquired during vaginal delivery through an infected birth canal

A

Conjunctivitis (ophthalmia neonatorum)

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24
Q

What swab is used to collect specimens for Neisseria gonorheae?

A

Dacron or rayon swabs

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25
Q

Transport medium for Neisseria gonorrheae

A

Amies medium with charcoal

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26
Q

Neisseria gonorrheae swab specimens placed in transport systems need to be plated within how many hours?

A

6 hours

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27
Q

Cotton swabs are considered toxic to this bacteria due to the presence of toxic fatty acids in the cotton fiber

A

Neisseria gonorrheae

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28
Q

How are blood specimens for Neisseria gonorrheae collected?

A

Blood is first collected in vacutainer tubes and then transferred to the broth culture system within one hour of collection. Routine blood cultures aren’t used because they are inhibited by SPS.

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29
Q

Body fluids (like joint fluid or CSF) is kept at what temperature?

A

Kept at RT or placed at 37ºC before plating

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30
Q

Urethritis with >5 PMN/field but no bacteria

A

Non-gonococcal urethritis (C. trachomatis)

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31
Q

Extracellular gram-negative diplococci are the ________ forms of Neisseria gonorrheae

A

Avirulent forms

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32
Q

What specimen is used for gram staining Neisseria gonorrheae?

A

Urogenital specimens

Pharyngeal specimens are not used because commensal Neisseria spp. may be present

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33
Q

Why are direct gram stains of bodily fluids cytocentrifuged?

A

Direct gram stain is best accomplished with cytocentrifugation because this concentrates small numbers of organisms (100 fold)

34
Q

Biochemical test results:

Cystine Trypticase agar: yellow color within 24-27 hours at 35-37ºC
Oxidase test: purple
Superoxol test: vigorous bubbling
Cephalosporinase test: deep pink/red color within 10 minutes
Beta lactamase: (+)
DNAse test: (-)

A

Neisseria gonorrheae

35
Q

Biochemical test: Neisseria gonorrheae

A

Glucose fermenter
Oxidase (+)
Superoxol test (+)
Cephalosporinase test (+) within 10 minutes
Beta lactamase (+)
DNAse (-)

36
Q

Confirms the biochemical identification using monoclonal antibodies directed against N. gonorrheae attached to killed S. aureus cells

A

Coagglutination

37
Q

A highly specific and sensitive test that uses monoclonal antibodies that recognize epitopes on the principal other membrane protein (Por) of N. gonorrheae. it also confirms the morphologic appearance of the bacteria

A

Fluorescent antibody test (FAT)

38
Q

This test detects gonococcal antigen or nucleic acid directly in specimens. It has the advantage of having the ability to test for Chlamydia trachomatis at the same time; less sensitive for transport and storage conditions. It is also suitable for screening many patients simultaneously.

A

Molecular assays - Nucleic acid amplification

39
Q

This test is a rapid, direct detection of gonococcal rRNA in genital and conjunctivital specimens. Its disadvantage is that it is not approved for pharyngeal or rectal specimens; cannot identify B-lactamase-producing strain; not applicable for susceptibility testing

A

Chemiluminescent Nucleic acid probe

40
Q

Virulence factor of Neisseria meningitidis

A

Pili
Polysaccharide capsule
IgA1
Cellular membrane proteins (Por A and Por B)
LOS endotoxin

41
Q

Causative agent of spotted fever

A

Neisseria meningitidis

Other names for spotted fever:
epidemic meningococcal meningitis / meningococcemia / cerebrospinal fever

42
Q

Leading cause of fatal bacterial meningitis

A

Neisseria meningitidis

43
Q

Microscopic appearance of Neisseria meningitidis

A

Intracellular or extracellular gram negative diplococci
Encapsulated strains can have a halo around organism

44
Q

It may be found as a commensal inhabitant of the upper respiratory tracts of the carriers; it colonizes the mucous membranes of nasopharynx and oropharynx

A

Neisseria meningitidis

45
Q

Has the tendency to invade serous and joint fluids, causing pleuritis and arthritis

A

Neisseria meningitidis

46
Q

Biochemical test:

Catalase (+)
Oxidase (+)
Superoxol (-)
Gamma-glutamyl aminopeptidase test (+)
Glucose and maltose fermenter; requires iron for growth

A

Neisseria meningitidis

47
Q

Biochemical test: Neisseria meningitidis

A

Catalase (+)
Oxidase (+)
Superoxol (-)
Gamma-glutamyl aminopeptidase test (+)
Glucose and maltose fermenter; requires iron for growth

48
Q

It refers to the presence of Neisseria meningitidis in the blood and can occur as an acute or chronic form. It occurs with or without meningitis.

Source of epidemics: oral secretions and respiratory droplets (person-to-person)

Signs and symptoms: frontal headache, stiff neck, fever (epidemic meningitis in adults)

A

Menigococcemia

49
Q

What skin lesion develops during bacteremic spread due to release of endotoxin after bacterial cell lysis?

A

Petechial skin lesions

50
Q

This complex activates the clotting cascade, depositing fibrin in small vessels, producing hemorrhage on the adrenals (Waterhouse-Friderichsen), altering peripheral vascular resistance, and leading to shock and death.

What complex and what bacteria is responsible?

A

LOS-endotoxin complex in Neisseria meningitidis

51
Q

People with deficiency in complement C5-C8 are at risk of…

A

Meningococcemia

52
Q

DOC for meningococcal meningitis

A

Penicillin G

53
Q

The colony morphology is similar to T3 colonies of N. gonorrheae on CAP

A

Neisseria cinerea

54
Q

Differentiates N. cinerea from N. gonorrheae

A

Colistin susceptibility

55
Q

Yellow-pigmented Neisseria spp.
assacharolytic

A

Neisseria flavescens

56
Q

Commonly found in the nasopharynx of infants and children. It is isolated from meningococcal carrier surveys, commonly from children 2 years old and rarely in adults.

A

Neisseria lactamica

57
Q

It is usually isolated from the nasopharynx of children or young adults. It has also been isolated from airways of dolphins.

A

Neisseria mucosa

58
Q

Culture morphology:
Dry, wrinkled, adherent and breadcrumbs-like colonies

A

Neisseria sicca

59
Q

A rod-shaped gram negative cocci with a weakly positive or negative catalase test

A

Neiserria elongata

60
Q

A rod-shaped gram negative cocci that is a normal oral microbiota in dogs and can be found in humans in infections following dog bites

A

Neisseria weaveri

61
Q

The most commonly isolated moraxella

A

Moraxella catarrhalis

62
Q

Moraxella is part of the normal flora of…

A

Upper respiratory tract (oropharynx)

63
Q

3rd most common cause of otitis media and sinusitis in children

A

Moraxella catarrhalis

64
Q

Culture morphology of Moraxella catarrhalis

A

Smooth, opaque, gray to white colonies with “honey puck” appearance
Colonies remain intact when pushed across the plate with a loop

48-hour colony may have elevated center, thinner wavelike periphery— “wagon wheel appearance”

65
Q

Definitive diagnosis of Moraxella catarrhalis

A

Butyrate esterase (+)

66
Q

Biochemical test: Moraxella catarrhalis

A

Oxidase (+)
Catalase (+)
Asaccharolytic
DNAse (+)
Butyrate esterase (+)
Nitrate reduction (+)

67
Q

Is a chocolate agar with an enrichment supplement (IsoVitaleX) and antibiotics (vancomycin, colistin, and nyacin)

A

Thayer Martin Agar

68
Q

Antibiotics present in Thayer Martin Agar

A

Vancomycin
Colistin
Nystatin

69
Q

Vancomycin inhibits the growth of…

A

Gram positive bacterias

70
Q

Colistin inhibits the growth of

A

Gram negative except Neisseria

71
Q

Nystatin inhibits the growth of…

A

Fungi

72
Q

Components of Modified Thayer Martin Agar (MTM)

A

Enrichment supplement (IsoVitaleX)
Antibiotics (vancomycin, colistin, nystatin)
Trimethoprim lactate

73
Q

Composition of Martin Lewis Medium (ML)

A

(MTM + nystatin replaced with anisomycin)

Enrichment supplement (IsoVitaleX)
Antibiotics (vancomycin, colistin, anisomycin)
Trimethoprim lactate

74
Q

A transparent medium with lysed horse blood, horse plasma, and yeast dialysate

Antimicrobial agents: vancomycin, colistin, trimethoprim, and amphotericin B

Advantage: genital mycoplasma will also grow on this agar

A

New York City Medium (NYC)

75
Q

What medium is used to isolate Neisseria gonorrheae?

A

New York City Medium (NYC)

76
Q

What medium contains NYC antibiotics + lincomycin

A

GC-LECT medium

77
Q

What is the purpose of gamma glutamyl aminopeptidase test?

A

The substrate, gamma glutamyl aminopeptidase is used to distinguish between gonococci and meningococci

78
Q

What requirement is followed for the inoculation of Neisseria?

A

The sensitivity of Neisseria to drying and extreme temperatures requires them to be directly inoculated at the bedside

79
Q

Culture morphology of Neisseria meningitidis

A

Encapsulated strains are mucoid in appearance; bluish gray-colonies (BAP)
Small, tan, mucoid colonies (CAP)

80
Q

Microscopic appearance of Neisseria meningitidis

A

Gram-negative intracellular diplococci

81
Q

Requires iron for growth

A

Neisseria meningitidis
Neisseria gonorrheae

82
Q

Major pathogens of Neisseria

A

Neisseria gonorrheae
Neisseria meningitidis

GRAM NEGATIVE COCCI AND GRAM NEGATIVE BACILLI (5 decks)

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