It is the causative organism of gonorrhoea and ophthalmia neonatorum.
Like meningococci, gonococci are Gram-negative diplococci and are often found intracellularly. Unlike meningococci, gonococci are non-capsulated. The endotoxin of gonococci is lipooligosaccharide, which differs slightly from the lipopolysaccharide found in many other Gram-negative bacteria.
They can be typed into more than 100 serotypes based on their pilus protein.
Gonococci cause gonorrhoea and ophthalmia neonatorum.
Gonorrhoea presents with purulent urethral discharge and dysuria in men. It may also cause epididymitis and proctitis. In women, it causes PID (pelvic inflammatory disease), which may lead to infertility and ectopic pregnancy from tubal scarring.
Disseminated gonococcal infection presents with septic arthritis, tenosynovitis, skin pustules, endocarditis, and meningitis.
Pili and outer membrane protein are important for initial attachment to the host cell. Non-piliated gonococci are avirulent.
Prophylactic erythromycin applied topically to the eye is given to all newborns at birth.
In men, a Gram stain of urethral discharge showing typical gonococcal morphology is sufficient for diagnosis. In women, Gram stain must be followed by culture to confirm the diagnosis. The sensitivity and specificity for urethral smears is 90% to 95%, respectively, versus 60% sensitivity and over 90% specificity for endocervical smears.
Culture medium should be chosen based on the specimen site. Sterile sites (such as blood) can be cultured on chocolate agar. Non-sterile sites (such as urethral discharge) are cultured on selective media such as Thayer Martin, Martin Lewis, or New York City medium. These are chocolate agar-based media to which antibiotics (vancomycin, colistin, trimethoprim) and an antifungal agent (nystatin or amphotericin B) have been added.
Gonococci are catalase positive and oxidase positive. They ferment glucose but not maltose.
Fluorescent antibody tests using antibodies that bind to outer membrane protein porins IA and IB can be used to confirm a culture as gonococcus. Coagglutination tests can also be used. Rapid, highly sensitive and specific nucleic acid tests can be performed on urine and vaginal swabs.
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