Neisseria gonorrhoeae 

• urethra in males 
• endocervix in females

Other sites may be infected

 Other sites that may be infected include the urethra in females, 

• urethra in females
• the rectum
• the oropharynx
• the eye

• Initial adherence is mediated by the pili made up of repeated protein subunits capable of phase and antigenic variation. 
• Opa (opacity) proteins are closely related outer membrane proteins and act as adhesins in the second phase or tighter binding. 

•  Inflammation is stimulated by lipooligosaccharide and possible peptidoglycan fragments of Neisseria gonorrhoeae. 
• The inflammatory response is also seen in females. Inflammation occurs typically at the endocervix; it is severe in the fallopian tubes when ascending infection occurs.

• The reservoir of gonococcal disease in the population is asymptomatic persons. 
  • As many as 50% of women and 5% of men will not experience recognizable symptoms. 
  • In addition, men who do not seek treatment may become asymptomatic carriers.

•  Diagnosis is established by Gram stain of the urethral discharge. 
  • Gram stain is more 90% sensitive and 98% specific in men.
  • In women, sensitivity and specificity drop to 5-70%. 
• Urethral swabs in males and cervical swabs in females should be plated on selective media (Thayer-Martin).

• You treat the patient with amoxicilin. He returns one week later stating that the treatment has had no effect on the discharge.
• Treatment should be started immediately. 
• Antibiotic options are 
  • a single dose of Ceftriaxone 125 mg. IM
  • Cefixime (Suprax) 400 mg p.o. 
  • Ciprofloxacin 500 mg. p.o.
  • Ciprofloxacin 400 mg. p.o.
• Erythromycin, doxcycline and spectinomycin are effective, but resistance is limiting their usefulness: 
• Concurrent treatment of Chamydia trachomatis is recommended as 50% patients with urethritis or cervicitis have concomitant chlamydia infection. Doxycycline 100 mg. Twice daily, or azithromycin 1 gram orally as a single dose, should be given along with one of the above antimicrobials.

•  The likely cause of treatment failure is penicillin resistance. Penicillinase-producing Neisseria gonorrhea (PPNG) were first described in the Far East, and are now endemic in the U.S. 
  • These strains produce a plasmid encoded beta-lactamase.

Vaccine

• They are associated with phase and antigenic variation. 
• Besides pili and Opa, gonococcal lipooligosaccharide also undergoes antigenic variation. 
• This complex, high frequency antigenic variation provides specific ligands for different cell receptors which allows the organism to escape from immune surveillance, and makes it very difficult to develop a vaccine.