PCR FOR DETECTION OF CHLAMYDIA-TRACHOMATIS IN ENDOCERVICAL, URETHRAL,RECTAL, AND PHARYNGEAL SWAB SAMPLES OBTAINED FROM PATIENTS ATTENDING AN STD CLINIC

Objective: To investigate, by use of the Amplicor PCR in a routine set ting, the recovery rate of Chlamydia trachomatis in ano-rectal and pha ryngeal swab samples obtained from males and females attending an STD clinic in relation to sexual practices, symptoms, and signs. Design: D ata regarding sexual practices, and symptoms and signs related to the rectum and pharynx, were obtained from 196 females and 208 males, incl uding 31 homosexuals and eight bisexuals. Swab samples were obtained f rom the urethra, rectum, and pharynx from all the patients. An additio nal endocervical swab sample was obtained from the females. Methods: A ll samples were analysed by the Amplicor PCR (Roche). Setting: Rudolph Bergh's Hospital, a clinic for sexually transmitted diseases situated in the centre of Copenhagen, Denmark. Results: The overall prevalence of urogenital C trachomatis infection was 9.2% (37/404). The specific ity of the Amplicor PCR was 100% for both ano-rectal and pharyngeal sw ab samples. In females three (13%) of the 23 infections were detected only by testing an ano-rectal or throat swab sample. In homosexual mal es two (67%) of three infections were detected only by the anorectal s wab sample. Ano-rectal intercourse without use of condom was reported by 44% of females and by 52% of homosexual males. Fellatio without con dom use was reported by 91% of females, and 80% of heterosexual males practised cunnilingus. Pharyngeal infection, however, occurred only in females, and the presence of pharyngeal symptoms or signs seemed pred ictive for pharyngeal C trachomatis infection, for which the time of i ncubation or colonisation exceeded 3 months. The presence of ano-recta l signs or symptoms was not predictive for an ano-rectal C trachomatis infection. Conclusion: The Amplicor PCR can be used on ano-rectal and pharyngeal swab samples. Anorectal swab samples should be obtained in females and homosexual males at high risk of being infected. Pharynge al samples should be taken in females at high risk of being infected, especially when pharyngeal signs or symptoms are present.