Neisseria gonorrhea

Categorization
Cell Wall: Gram Negative Shape: Cocci, Diplococci
Metabolism: Obligate Aerobe
Culture and Detection
  • Culture: All Neisseria can be selectively grown on the Thayer-Martin chocolate agar selective media supplemented with the antibiotics Vancomycin, Colistin, and amphotericin
  • Detection: Detection of intracellular gram negative diplococci
  • Biochemistry: G. gonorrhea is negative for maltose fermentation and can distinguish it from G. meningitides.
Virulence Factors
  • Pili: Allows adherence to epithelial cells. Antigenic variation of pili allows for immune evasion and ineffectiveness of vaccines.
  • IgA Protease: Reduces mucosal immunity.
Transmission
  • Adults: Sexually Transmitted Disease
  • Neonates: Mother-to-Child Transmission during delivery
Clinical Consequences
  • Overview
    • Gonococcus initially infects mucous membranes. If untreated, the initially infected tissues may undergo scarring and the organism may spread systemically leading to a number of serious complications.
  • Gonococcus in Men
    • Infection may be completely asymptomatic but organism is still infectious. Infection yields urethritis and is usually accompanied by dysuria, frequency, and purulent urethral discharge. If left untreated, organism can locally spread to cause epididymitis and prostatitis. Long term local infection may result in strictures of the urethra.
  • Gonococcus in women
    • Cervicitis: Can be observed as an edematous, friable cervix with purulent discharge that may lead to vaginal discharge
    • Urethritis: Due to infection of the urethra and is sometimes accompanied by dysuria and frequency
    • Endometritis and salpingitis: Due to local spread to uterus and fallopian tube which is often categorized as PID and can manifest as dyspareunia and abdominal pain.
    • If left untreated, scarring of the fallopian tube may lead to infertility and increased risk of ectopic pregnancy. Extensive, localized spread may present as Fitz-Hugh-Curtis Syndrome.
  • Gonococcus in Neonates
    • Gonococcus can infect a neonate during delivery. Results in a characteristic conjunctivitis termed "Ophthalmia Neonatorum". Damage to cornea can lead to blindness if untreated.
  • Complications
    • These complications are due to disseminated bacteremic spread of the initially localized infection
    • Bacteremia: Characterized by high fevers
    • Joints: Gonococcal arthritis usually affects one or two joints and is the most common form of septic arthritis among young sexually active adults.
    • Skin: Petechia, papules, and pustules with hemorrhagic bases are commonly seen in disseminated infection
    • Infective Endocarditis and meningitis: Are possible with further dissemination but are now rare
Treatment
  • Ceftriaxone is now recommended therapy. Doxycycline or azithromycin are often given concurrently to cover frequent co-infection with Chlamydia trachomatis.