Prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae infection in adolescents in Northern Italy: an observational school-based study.

BACKGROUND: We carried out a study to evaluate the prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae genital infections in school-based adolescents in Northern Italy. METHODS: Systematic screening for C. trachomatis and N. gonorrhoeae genital infection was performed in 13th grade students in the province of Brescia, an industrialized area in Northern Italy. Student filled in a questionnaire on sexual behaviour and provided a urine sample for microbiological testing. RESULTS: A total of 2,718 students (mean age: 18.4 years; 59.1 % females) provided complete data (62.2 % of those eligible). Overall 2,059 students (75.8 %) were sexually active (i.e. had had at least one partner), and the mean age at sexual debut was 16.1 years (SD: 1.4). Only 27.5 % of the sexually active students reported regular condom use during the previous 6 months, with higher frequency in males than in females (33.8 % vs 24.2 %). No case of N. gonorrhoeae infection was detected, while C. trachomatis was found in 36 adolescents, with a prevalence of 1.7 % (95 % CI: 1.2-2.4) among sexually active students, and no statistical difference between females and males (1.9 and 1.4 %, respectively). Inconsistent condom use (odds ratio, OR = 5.5) and having had more than one sexual partner during the previous 6 months (OR = 6.8) were associated with an increased risk of Chlamydia infection at multivariate analysis. CONCLUSION: The prevalence of C. trachomatis infection among sexually active adolescents in Northern Italy was low, despite a high proportion of students who engage in risky sexual behaviour. No cases of N. gonorrhoeae infection were identified.