Neisseria Gonorrhoeae

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  • diplocoocus
  • gram-negative
  • non-encapsulated
  • non-motile

Gonococci

  • cause gonorrhea which is a sexually transmitted disease (STD)

Antigenic Structure and Virulence Factors

1. Pili

  • among the most important virulence factor
  • mediate attachment to epithelial and mucosal cells
  • antiphagocytic
  • antigenic
  • non-piliated strains are avirulent

2. Lipooligosaccharide (LOS)

  • located in the cell wall
  • responsible for endotoxic effects occurring in gonococcal infection

3. Opacity (opa) Proteins

  • located on the outer membrane gonococci
  • antigenically diverse in different strains of
  • undergo phase-variable expression
  • promote persistence of N. gonorrhoeae in the female genital tract
  • gene phase variation allows gonococci to evade immune response and cause repeated infections
  • presence renders gonococcal colonies less translucent

4. Por Proteins

  • extends through gonococcal cell membrane
  • may prevent intracellular killing of gonococci within neutrophils by preventing phagosome-lysosome fusion

5. IgA1 Protease

  • hydrolyzes immunoglobulin IgA1

Clinical Significance

  • Gonococci attack mucous membranes of the: genitourinary tract, eye, anorectal area, and throat
  • producing acute suppuration that may lead to tissue invasion, chronic inflammation and fibrosis
  • females are generally asymptomatic

Genitourinary Tract Infections

  • In males:
    • symptoms are acute and easier to diagnose
    • presents with purulent urethral discharge and dysuria
  • In females:
    • infection occurs in the endocervix and extends to the urethra and vagina
    • a greenish-yellow cervical discharge is most common, often accompanied by intermenstrual bleeding
    • disease may progress to the uterus, causing salpingitis (infertility may occur as a result of tubal scarring), pelvic inflammatory disease (PID), and fibrosis

Rectal Infections

Characterized by:

  • constipation
  • painful defecation
  • purulent discharge

Pharyngitis

  • Infected individuals may show %%purulent exudate%%

Ophthalmia Neonatorum

  • infection of the conjunctival sac that is acquired by a newborn during passage through the birth canal of an infected mother
  • if untreated acute conjunctivitis may lead to blindness
  • treatment: erythromycin

Disseminated Infection

  • bacteremia with gonococci is rare
  • strains that invade the bloodstream may result in disseminated infection in which the organism can cause:
    • fever
    • painful, purulent arthritis
    • small pustules on the skin that are scattered and single on an erythematous base
  • more common in women

Treatment

  • More than 20% of gonococci are resistant to penicillin, tetracycline, cefoxitin, and/or spectinomycin
  • third-generation cephalosporins are recommended
    • a single intramuscular dose of ceftriaxone is recommended for uncomplicated gonococcal treatment of the urethra, endocervix, or rectum
  • intramuscular spectinomycin is indicated in patients allergic to cephalosporins