[Diagnosis of Chlamydia trachomatis infection in a clinic for sexually transmitted disease: evaluation of cervical, urethral and rectal swab samples by polymerase chain reaction].

INTRODUCTION: The aim of this study is to analyze the clinical and epidemiological characteristics of Chlamydia trachomatis infection in patients attended in a clinic for sexually transmitted disease in Seville (Spain). Microbiological diagnosis was performed in various types of samples.

MATERIAL AND METHODS: The study included 3854 patients (50.8% women and 49.2% men, mean age 30.1 years) seen from 2002 to 2004. Among the total, 50% belonged to groups engaging in high risk sexual practices: female commercial sex workers (CSWs) (47%), men who maintain sexual relationships with other men (MSM) (45%), users of prostitution (4%), promiscuous heterosexual men (4%), those with a risk partner (2.7%) and injection drug users (IDU) (2.2%). We analyzed a total of 5978 samples (2384 cervical exudates, 2645 urethral exudates and 949 rectal exudates), for the detection of C. trachomatis by PCR technique with the COBAS Amplicor CT System.

RESULTS: Prevalence of C. trachomatis infection was 6% (4.3% in women and 7.8% in men). Among the total in women, 51.2% of positive samples were from women with high-risk sex factors and 73.8% of the women were asymptomatic. In men, the proportions were 70.5% and 36.9%, respectively. Cervical, urethral and rectal exudates yielded positive results in 4%, 4.9% and 4.3%, respectively.

CONCLUSIONS: Systematic sampling for C. trachomatis detection is necessary in symptomatic and asymptomatic patients practicing high-risk sex; periodic follow-up studies are also needed for early detection of sexually transmitted infection. Rectal sample collection is important for detecting this infection in MSM and in patients whose sexual habits make it advisable.