N.gonorrhoeae

Question 1

Classification

Answer 1

Family: Neisseriaceae

Genus: Neisseria

Species: gonorrhoeae

Gonococcus

Question 2

Morphology

Answer 2

Gram-negative cocci
Typically diplococci (kidney shaped)
Usually present inside PMNLs
Possess pilli on their surface

Question 3

Growth characteristics

Answer 3

Aerobic organisms
Grow in atmosphere with 5% CO2
Fastidious organisms
Grow only on complex media- N.gonorrhoea is more fastidious
Oxidase positive
Catalase positive
Neisseria species are very sensitive to:
- drying
- chilling (temp below 37)
- exposure to sunlight

Question 4

Antigenic structure

Answer 4

Pilin proteins:

Antigenic variation of pilin proteins
Phase variation pilin expression

Outer membrane proteins:
Antigenic variations

Lipopolysaccharide:
Lipid A
Core oligosaccharide

Question 5

Virulence factors

Answer 5

Pili
Outer membrane proteins
Lipopolysaccharide (endotoxin)
IgA1 protease

Question 6

Disease

Answer 6

Gonorrhoea (genital infection)
Anorectal gonorrhea 
Disseminated infections
Ophthalmia neonatorum 
Pharyngeal gonococcal infection 

Gonorrhea (genital infection):

• urethritis in men
• endocervicitis in female

Question 7

Microbiological diagnosis

Answer 7

DME:

• gram-stained smear: kidney-shaped gram-negative diplococci and PMNLs
• methylene blue stain: kidney-shaped diplococci and PMNLs

Culture:
Thayer-Martin medium (chocolate agar + antibiotics) in 5% CO2- convex, opaque, glisten colonies

Specific tests:

Oxidase- positive
Glucose- positive

Question 8

Treatment and prevention

Answer 8

• ceftriaxone is the drug of choice

- spectinomycin or ciprofloxacin is recommended