Neisseriae Flashcards

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1
Q

General Morphology

A

Gram Negative diplococci (bean-shaped)

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2
Q

Where are non-pathogenic Neisseria found?

A

Commensals in Nasopharynx

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3
Q

Neisseria gonorrhea- General characteristics (4)

A

Fastidious Gram-negative diplococci (bean-shaped)

Grow at 37 degrees on layer blood and chocolate agar in atmosphere of 5-10% CO2

Oxidase positive

Identification: Glucose utilization —> acid

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4
Q

Neisseria gonorrhea- Pathogenicity (3)

A

1- FIMBRIAE or TYPE IV PILI —> attachment to mucosal surface

2- CATALASE —> Resistance to Intracellular killing by Phagocytic cells (protects organism from toxic effects or O2 radicals)

3- ANTIGENIC VARIATION —> FIMBRIAE and OUTER MEMBRANE PROTEIN II

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5
Q

Neisseria gonorrhea- Habitat

A

NEVER NORMAL FLORA

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6
Q

Neisseria gonorrhea- Local Infections (4)

A

Acute urethritis in males

95% symptomatic (male)

Dysuria, urethral discharge

Local spread: epidiymitis, prostatitis, urethral stricture

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7
Q

Neisseria gonorrhea- Clinical Features (3)

A

1- Acute vaginitis and Endocervicitis

- 50% of females symptomatic
- Local spread: PID, Salpingitis, Infertility 
- Ophthalmia neonatorum 

2- Disseminated Gonococcal Infection

- Common in female
- Fever, arthritis, septic skin lesions on extremities 
- Rarely: meningitis, infective endocarditis 

3- Vulvovaginitis in prepubertal girl
- Child abuse

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8
Q

Neisseria meningitidis- General Characteristics (4)

A

Fastidious, aerobic Gram-negative diplococci (bean-shaped)

Grow at 37 degrees on blood and chocolate

Oxidase positive

Identification: Glucose and Maltose positive

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9
Q

Neisseria meningitidis- Viability

A

Organism die quickly at room temp outside human host

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10
Q

Neisseria meningitidis- Serogroup Typing (3)

A

1- Produces POLYSACCHARIDE CAPSULE

2- 13 serogroup: A, B, C, X, Y, Z, W-135 (commonest = A, B, C)

3- Typing: slide agglutination with specific antisera

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11
Q

Neisseria meningitidis- Major serogroups (5)

A

A —> Epidemic meningitis (Africa) —> Vaccine

B —> Epidemic strains (outbreaks) —> Vaccine

C —> Local outbreaks —> Vaccine

W-135 —> Pilgrims returning from Haj —> Vaccine

X, Y, Z —> Rare

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12
Q

Neisseria meningitidis- Reservoir

A

Human Nasopharynx

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13
Q

Neisseria meningitidis- Pathogenesis (2)

A

1- TYPE IV PILUS —> mucosal colonization of Nasopharynx

2- POLYSACCHARIDE CAPSULE —> resist host immune defense

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14
Q

Neisseria meningitidis- Clinical Features (4)

A

Meningitis

Conjunctivitis

Arthritis

Infective endocarditis

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15
Q

Neisseria meningitidis- Age Risk Factor

A

3months - 3years

18-23years

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16
Q

Neisseria meningitidis- Virulence Factors (3)

A

1- POLYSACCHARIDE CAPSULE —> prevent phagocytosis

2- LOS ENDOTOXIN —> present in OUTER MEMBRANE, damage to BLOOD VESSELS associated with meningococcal infection

3- LIPOOLIGOSACCHRIDE —> stimulates TNF-a which results in HOST CELL DAMAGE

17
Q

Neisseria meningitidis- Immunoprophylaxis

A

A, B, C, Y, W-135