Neisseria gonorrhoeae

Question 1

What are the pathogens species in family Neisseriaceae?

Answer 1

N. gonorrhoeae, N. meningitidis, Moraxella catarrhalis

Question 2

What is the gram staining and morphology of Neisseria and Moraxella?

Answer 2

Gram-negative diplococci. Single cocci are kidney-shaped, flat on one side.

Question 3

What environment is required for culturing Neisseria and Moraxella (media, gasses, temp, pH)?

Answer 3

Rich media
5% CO2
Rapid autolysis occurs at 25C and alkaline pH.

Question 4

What allows for repeated infections gonorrhoeae infections?

Answer 4

N. gonorrhoeae is antigenically very heterogeneous and capable of changing its surface structures (antigenic variation and phase variation) to avoid host defenses. Because there is so much antigenic variation by N. gonorrhoeae a single person can be infected with N. gonorrhoeae many times (>10X) in their lifetime.

Question 5

What are pili used for, and how does Neisseria use them to evade host defenses?

Answer 5

Pili are important for attachment to the mucosal epithelium. There are hundreds antigenic types of pili (called - antigenic variation). In addition, the bacteria are capable of switching on and off the expression of pili (called - phase variation).

Question 6

What are Opa proteins?

Answer 6

Opa proteins are outer membrane proteins. N. gonorrhoeae colonies can either be transparent, opaque, or mixed depending on the presence of Opa proteins at the bacterial surface. Opa proteins are important for attachment and may influence the site and type of infection.

Question 7

What is LOS and what does it cause?

Answer 7

Lipo-oligosaccharide (LOS) is the equivalent of the lipopolysaccharide (LPS) of gram-negative bacteria, but without the long O-side chains. There are eight or more types of LOS. LOS is toxic for ciliated cells in tissue cultures. LOS is probably responsible for many of the inflammatory processes seen during an infection.

Question 8

What sort of protease does Neisseriaceae possess that helps it evade host defenses?

Answer 8

IgA protease cleaves the Fc portion of human IgA, preventing opsonized bacteria to become phagocytosed.

Question 9

What are the four surface structures that Neisseriaceae uses to evade host defenses?

Answer 9

Pili - 100’s of types = antigenic variation, & phase variation
Opa proteins
LOS - 8+ types, toxic to ciliated cells, likely inflammatory
IgA protease - cleaves Fc portion of IgA

Question 10

Who are more likely to be asymptomatic carriers of gonorrhoeae and what condition may this lead to?

Answer 10

The prevalence of asymptomatic carriers is much greater among women. Asymptomatic carriers are a major problem in the control of gonorrhea and asymptomatic infection particularly in women can lead to a more serious infections (e.g. pelvic inflammatory disease).

Question 11

What should be suspected in a case of gonorrhoeae infection in a pre-pubescent?

Answer 11

Sexual abuse is the most frequent cause of gonococcal infection in preadolescent children. Gonococcal infection in children should immediately suggest child abuse and be further investigated by contacting police and social workers.

Question 12

What are the common clinical manifestations of gonorrhoeae infection in the lower tract?

Answer 12

1. Cervicitis
2. Abscess formation in glands adjacent to the vagina
3. Urethritis

Question 13

What are the common clinical manifestations of gonorrhoeae infection in the upper tract?

Answer 13

1. Endometritis
2. Pelvic inflammatory disease (in at least 15% of cases) More likely to occur in women with recent asymptomatic infection.
3. Epididymitis

Question 14

What are the common clinical manifestations of localized gonorrhoeae infection outside the urogenital system?

Answer 14

1. Proctitis – more frequently found in homosexual men.
2. Pharyngitis (in 20% of infected homosexual men or heterosexual women)
3. Ophthalmia neonatorum (bilateral conjunctivitis in infants born of infected mothers)
4. Peritonitis and perihepatitis

Question 15

What are the common clinical manifestations of systemic gonorrhea infection?

Answer 15

1. Dermatitis-arthritis-tenosynovitis syndrome
2. Monoarticular septic arthritis
3. Endocarditis (rare)
4. Meningitis (rare)

Question 16

How is the risk of HIV infection increased by a gonorrhea infection?

Answer 16

In persons who are not infected with HIV, the same inflammatory cells elicited by gonococcal infection provide a ready target for HIV infection; thus, risk of HIV acquisition is very likely increased in this setting.

Question 17

What will gram staining of exudates reveal in a gonorrhea infection?

Answer 17

Gram stained smears of urethral or endocervical exudates reveal many diplococci WITHIN polymorphonuclear cells (PMNs). This is true only for urogenital infections with N. gonorrhoeae. It is NOT true for other kinds of infection (e.g. oral pharyngeal infections).

Question 18

What is the sensitivity and specificity of gram staining of exudates in a gonorrhea infection for men and for women?

Answer 18

Sensitivity: 90% for men, 50% for women. Specificity: 99% for men, 90% for women.

Question 19

What is the current recommended antibiotic treatment for gonorrhea infection?

Answer 19

Ceftriazone, single dose IM (250mg) plus
Azithromycin, single dose oral (1 gram) or
Doxycycline, 2X daily for 7 days oral (100mg)
Affect different targets simultaneously

Question 20

What other infection should be suspected and treated with any gonorrhea infection?

Answer 20

Chlamydia trachomatis
Patients infected with one are often infected with the other
The cost of treating for both is less than the cost of testing.
Azithromycin also treats C trachomatis

Question 21

What is the prophylactic treatment given at birth for ocular infection in infants born from infected mothers?

Answer 21

1% silver nitrate solution,
erythromycin ointment,or
tetracycline ointment

PS: The efficacy of these preparations in preventing chlamydial ophthalmia is less clear, and they do not eliminate nasopharyngeal colonization by C. trachomatis.

Question 22

What is the treatment of ocular infection with N. gonnorheae?

Answer 22

Ceftriaxone (IV or IM, single dose). Topical antibiotic alone is inadequate.

Question 23

What is the treatment of ocular infection with C. trachoma’s?

Answer 23

Erythromycin (orally, 10-14 days). Topical antibiotic alone is inadequate.

Question 24

What is the treatment of pregnant women infected with N. gonorrhoeae? With C. trachomatis?

Answer 24

N. gonorrhoeae infection:
Third generation cephalosporins or spectinomycin (single doses)

C. trachomatis infection:
Erythromycin (orally for 7 days) or Amoxicillin (orally for 7 days)