Bacterial Infections

Neisseria Gonorrhoeae

Pathogenesis
Neisseria gonorrhoeae is a gram-negative bacterium that has the unique genetic ability to change the antigenic expression of its surface-exposed proteins. This ability has made the development of a gonococcal vaccine difficult. The pathogenesis of infection includes the presence of pili, which are hair-like appendages needed for attachment, and the lipooligosaccharide (LOS) gonococcal endotoxin, which damages host epithelial cells such as fallopian tube cells.

Clinical Syndromes
The most common manifestation of gonococcal disease among men is urethritis, which may be asymptomatic. After urethral inoculation with the organism during sexual activity, it is estimated that 2 to 4 days elapse before symptoms of dysuria and/or discharge appear. The discharge may be scant and mucoid or may present as a profuse purulent discharge. Untreated gonococcal urethritis in men typically resolves over 1 to 2 months but may progress in up to 10% of cases to acute epididymitis and urethral strictures. An outline of the evaluation of urethritis is presented in Fig. 3-6.

Although women have urethral infections, they are usually associated with endocervical infection. Most gonococcal infections in women affect the lower genital tract with a particular predilection for the columnar cells of the endocervix. Syndromes in both men and women are outlined in Table 3-16. In particular, disseminated gonococcal infection (DGI), a blood-borne infection manifested by skin lesions, tenosynovitis, and/or septic arthritis (culture-positive joint fluid in approximately 50% of cases only), occurs in 2 to 5% of infected individuals. However, it is more common in African- Americans than in other race/ethnicity groups. Pelvic inflammatory disease is another important complication of gonococcal infection.

Diagnosis and Treatment
Diagnostic tests are outlined in Table 3-16, evaluation of both urethritis and vaginitis is found in Figs. 3-6 and 3-7, and treatment regimens are summarized in Table 3-17. As stated by the Centers for Disease Control in the STD treatment guidelines (1993), treatment of gonococcal infections in the United States is based on the following: (1) the anatomic site of infection; (2) the antibiotic resistance [penicillinase-producing strains (PPNG), tetracycline-resistant strains (TRNG), and chromosomally mediated resistance to multiple antibiotics]; (3) high prevalence of concurrent chlamydial infections in patients with gonococcal infection; and (4) the side effects and costs of different treatment regimens. While treating for gonorrhea, screen for syphilis by serology. Treatment regimens that include ceftriaxone or a 7-day course of doxycycline (or erythromycin) may be effective against incubating syphilis, but few studies are available. Therefore, all patients with an STD should be screened for syphilis serologically.