bacteriology

They are made up of pilin protein and the amino acid sequence near the carboxyl terminal is highly variable; this portion of the molecule is most prominent in the immune response. the pillins of all stains of N. gonorrhoeae are antigenically different, and a single strain can make different antigenic form of pillin. Por proteins this protein extends through the gonococcal cell membrane. Por protein may prevent intracellular killing of gonococci within neutrophils by preventing phagosome- lysosome fusion. each strain of gonococci expresses only one of two types of por (A or B), but the por of different strains is antigenically different.

Opa proteins These proteins function in adhesion of gonococci within colonies and in attachment of gonococci to host cells. a strain of gonococcus can express no, one, two or occasionally there types of Opa proteins. RMP (protein III) It is a reduction- modifiable protein (RMP) and changes its apparent molecular weight when in a reduced state. It associates with por in the formation of pores in the cell surface. Lipooligosaccharide (LOS). It differ from LPS of enteric Gram-negative rods, in that gonococci LPS dose not have long O antigen side chains and is called as LOS. toxicity in gonococcal infections is mostly due to the endotoxic effects of LOS. LOS molecules structurally resemble human cell membrane glycosphingolipids. This helps gonococci evade immune recognition. other proteins have poor roles in pathogenesis. Lip(H8) surface protein Fbp (iron binding protein) expressed when iron supply is limited as in human infection. IgA, protease inactivate IgA,

Pathogensis and clinical findings Gonococci attack mucous membranes of the genitourinary tract, eye, rectum and throat, producing acute suppuration that lead to tissue invasion. This is followed by chronic inflammation and fibrosis. In males, there is usually urethritis with yellow, creamy pus and painful urination. Some time suppuration subsides in untreated infection, fibrosis occurs and may lead to urethral strictures. In certain cases urethral infection can be asymptomatic. In females, the primary infection is in the endocervix and extent to the urethra and vagina with production of mucopurulent discharge. It may then progress to the uterine tubes, causing salpingitis and fibrosis. Infertility occurs in 20% of women with gonococcal salpingitis. In chronic gonococcal cervicitis or proctitis they are asymptomatic. Gonococcal bacteremia lead to skin lesions (hemorrhagic papules and pustules) on the hands, forearms, feet and legs and to tenosynovitis and suppuortive arthritis, usually of the knees, ankles, and wrists. Gonococcal ophthalmia neonatorum (present as conjunctivitis) Infection of the eye of the new borne,

DiagnosisPus and secretions are taken from the urthera, cervix, rectum, conjunctiva, throat or synovial fluid for culture and smear. Blood culture is necessary for systemic infection.Gram-stained smears of urethral or endocervical exudates reveal many Gram negative diplococci within pus cells. These give presumptive diagnosis. Culture of urethral exudates from men are not necessary when the direct smear is positive but culture should be done for women. Stained smears from conjunctival exudates can also be diagnostic, but those from rectum and throat are not helpful. Culture Inoculation of the clinical specimens on enriched selective medium (e.g. modified Thayer- Martin medium) with vancomycin, colistin, amphotericin β, and trimethoprim to inhibit the contaminated organisms, then incubated in 5% CO2 condition at 37C°. The organisms can be identified by:their appearance on a Gram-stained smear.Oxidase positiveImmunofluorescene stainingfermentation test

Nucleic acid technology Nucleic acid (NA) probe is used to detect the gonococcal NA in the sample. This test is more sensitive and specific.Antigen detection method of gonococcal antigens in patient's secretions by enzyme immunoassay (ELA).TreatmentIn uncomplicated genital or rectal infections can be treated with ceftriaxone given intramuscularly as a single dose. Additional therapy with doxycycline, orally twice a day for 7 days; erythromycin is substituted for doxycycline in pregnant women.Fluoroquinolones (ciprofloxacin) used as a single oral dose.Spectinomycin for pts. allergic to β lactum drugs. A single dose given intramuscularly.

Epidemiology N. gonorrhoeae is generally transmitted from person to person via sexual intercourse. It may also transmitted from mother to infant during childbirth. Gonococcal infections are mostly asymptomatic and undiagnosed. This lead to spreading of the infection. N. gonorrhoeae is weakly immunogenic, and has different serotypes, therefore, pts. In high risk groups may have repeated gonococcal infections. High risk groups are adults mostly between 20-24 years of age, particularly unmarried of low socioeconomic status.

Control and prevention Rapidly eradicating gonococci from infected individuals by mean of early diagnosis and treatment. The infection rate can be reduced by avoiding multiple sexual partners. Mechanical prophylaxis (codoms) may provide partial protection. Gonococcal ophthalmia neonatorum is prevented by local application of 0.5% erythromycin ophthalmic ointment or 1% tetracycline ointment to the conjunctive of neoborns.