Background: Chlamydia trachomatis is responsible for 30 to 50% of genital tract infections and is present, without symptoms, in 20% of men and 60% of women. We have little information in Chile about the prevalence of this infection.
Aim: To assess the prevalence of Chlamydia trachomatis in men, using first catch urine samples.
Subjects and methods: Three hundred and fifty one first catch urine samples of asymptomatic men and 50 samples coming from men with a primary urethritis, were analyzed. Urethral discharge samples from the latter were simultaneously studied. Analysis was performed using an enzyme immuno analysis (MicroTrak Chlamydia EIA, Syva Co.) and a nested polymerase chain reaction towards the gene that codifies MOMP (PCR/OMP).
Results: Among asymptomatic men, two of 154 teenagers aged 18 to 19 years old (1.3%), 10 of 100 university students (10%) and eight of 97 adults over 30 years old (8.2%), were infected. The global prevalence of infection in these men was 5.7%. The prevalence of infection in men with urethritis was 12%. Urine EIA had a higher detection frequency than PCR/OMP, but according to another PCR assay, these results were false positives. EIA in first catch urine, had a sensitivity, specificity, positive and negative predictive value of 83.3, 75, 31.3 and 97% respectively, for the detection of Chlamydia trachomatis. The figures for PCR/OMP were 100% for all these parameters.
Conclusions: The prevalence of Chlamydia trachomatis infection in Chilean men is similar to that reported in developed countries. Enzyme immuno assay in first catch urine had a good diagnostic accuracy and could be used in epidemiological studies in asymptomatic men.