Part 3: Gram-negative Cocci

Question 1

The two gram-negative cocci:

Answer 1

1. Neisseria gonorrhoeae.
2. Neisseria menigitidis.

Question 2

Virulence factors common to both N. gonorrhoeae and N. menigitidis:

Answer 2

1. LOS (endotoxin; lipid A).
2. Opa (PII adhesion).
3. Pili (adhesion).
4. IgA protease.
5. Iron extraction system.

Question 3

Which virulence factor does N. menigitidis have that N. gonorrhoeae does not?

Answer 3

polysaccharide capsule (antiphagocytic).

Question 4

The two adhesin virulence factors of N. gonorrhoeae and N. menigitidis:

Answer 4

pili and Opa proteins.

Question 5

What type of agar is utilized to grow N. gonorrhoeae and N. menigitidis?

Answer 5

• Chocolate agar with a VPN (Thayer Martin) medium.
  
  • VPN: vancomycin, polymycin, nystatin.

Question 6

Clinical manifestations of N. gonorrhoeae (men versus women):

Answer 6

1. Men: urethritis, prostatitis.
2. Women: Cervicitis, PID, infertility, FHC.
3. Septic joints (knee).
4. Neonate conjunctivitis.

Question 7

Treatment for N. gonorrhoeae (2):

Answer 7

1. ceftriaxone for gonorrohea.
2. azithromycin or doxyclycline to cover chlamydia co-infection.

Question 8

Where is N. menigitidis located in human carriers, and how is it spread?

Answer 8

nasopharynx; respiratory droplets.

Question 9

The two primary differences between N. gonorrhoeae and N. menigitidis:

Answer 9

• N. menigitidis ferments maltose and has a polysaccharide capsule.
• N. gonorrhoeae can do/has neither.

Question 10

What are the signs of meningococcemia (N. menigitidis infection of blood)?

Answer 10

1. petechial rash.
2. LOS-mediated septic shock.
3. adrenal collapse (Waterhouse-Friderichsen Syndrome).

Question 11

What are the signs of bacterial meningitis (N. menigitidis infection of CSF)?

Answer 11

1. severe headache.
2. stiff neck.
3. photosensitivity.

Question 12

Treatment for N. menigitidis:

Answer 12

• Ceftriaxone or penicillin for infected.
• Rifampin prophylaxis for close contacts.

Question 13

Diagnostic identification of N. gonorrhoeae and N. menigitidis:

Answer 13

1. gram-negative diplococci often within PMNs.
2. culture on Thayer Martin (VPN) chocolate agar.
3. oxidase positive.
4. both ferment glucose (NM also maltose).

Question 14

How to differentiate N. menigitidis from N. gonorrhoeae in laboratory:

Answer 14

Only N. menigitidis can ferment maltose.

Question 15

The two vaccines for N. menigitidis:

Answer 15

1. MCV4 (serogroup A/C/Y/W135 conjugate vaccine).
2. TRUMENBA (serogroup B vaccine).