Objective: Determination of prevalence of genital chlamydiosis in similar group of adolescents as in that examined two years ago. Comparison of the results with the previous ones to confirm positive impact of a repeated screening on drop of prevalence of the infection. Another objective is to make the epidemiological data on genital chlamydiosis in the countries of the „Eastern Block“ more accurate, and at the same time to assess the most suitable screening method. Design: Prospective epidemiological study aimed at finding whether the repeated screening examinations of genital chlamydiosis in adolescents will result in decreased incidence of the infection. Setting: Veterinary Research Institute, Department of Clinical Microbiology of the Faculty Hospital, Regional Hygienic Station, Department of Gynecology and Obstetrics, Medical Faculty, Masaryk University, Brno. Methods: The groups under testing comprised male and female students of two secondary medical schools and one private grammar school older than 18 (n=232, of which 33 were boys and 199 girls). Direct detection of C. trachomatis was carried out from the urinary sediment of the sample of morning urine using ligase reaction, polymerase chain reaction, ELISA and direct immunofluorescence. Results: Identical positive result of C. trachomatis detection by four methods was obtained 4 times, i.e. 1.7%. The result of LCR and PCR were positive identically (4 times), ELISA and IF were, besides the above results, positive in other 1 resp. 5 cases. Conclusion: Screening examinations of genital chlamydiosis were performed in adolescents in the town of Brno. Morning samples of urine from 232 students of secondary schools were examined on C. trachomatis using the following methods: LCR, PCR, ELISA, and IF. The LCR and PCR were positive 4 times, ELISA 5 times, IF 9 times. Positive results by LCR and PCR were identical. ELISA and IF were positive in other cases. Noninvasive methods are suitable for screening of latent genital chlamydiosis and for estimation of its prevalence. The authors of the study recommend the ligase chain reaction (LCR) as a most suitable screening method.

        Key words: C. trachomatis, adolescents, screening