Neisseria Gonorrhoeae

Main points here are:

• Causes gonorrhoeae, infects columnar epithelial cells of cervix (females) & urethra (males). Colonies also form in mucosa of pharynx and rectum.

• Transmission between humans (only), only via intimal contact (genital, anal, oral sex)

• 50% of women contract disease post-sex with infected male, 20% of men contract disease post-sex with infected female.

• Symptomology:

  • Males:

    • Painful urination, copies purulent discharge from urethra (investigation of discharge reveals diplococci within polymorphonuclear leukocytes). 10% asymptomatic.

  • Females:

    • Symptoms more obvious, purulent discharge from vagina may be present with pain and itching. 50% asymptomatic.

  • Pharyngitis and purulent anal discharge evident if colonisation to throat or rectum.

• Untreated infections:

  • Female

    • Salpingitis, PID, infertility

  • Male

    • Prostatitis, epidydimo-orchitis, balantitis (inflammation of glans penis)

  • Septacaemia (1% of total cases):

    • Multiple pustular skin lesions in extremities leading to ≫septic arthritis, endocarditis, & meningitis. Can infect pregnant women ≫ infect babies as they pass vagina ≫ infant blindness ≫ ophthalmia neonatorum.

Pathogenesis

• Strategies employed to cause disease:

  • Pili  initial cell adhesion, Protein II (opa) ≫ more intimate attachment + initiates phagocytosis, Protein I (por) ≫creates pores in host membrane vacuole therefore phagolysosome not able to function, outer membrane oligosaccharide LOS mediates attachment btw bacterial cells ≫ initiates inflammatory process (cause most symptoms by this process ≫ eg: LOS mediates sterility in women with gonococcal salpingitis due to TNF-alpha release mediating scar tissue of uterine tubes).

  • Specific destruction of IgA by IgA1 protease

  • Continuous variation of surface of N.gonorrhoeae makes re-infection possible (immunity difficult).

Vaccines

• No vaccine available become surface proteins change. Protein I (not well displayed for antibody binding) only candidate for vaccination as it doesn’t change within strains but does change btw strains (but some areas in gene coding for this protein are conserved).

Prevention

• Safe sex practices, screening of society, antibiotics (cocktail of them).

Category: Microbiology Notes