BACKGROUND:Infection with genital Chlamydia trachomatis (Ct) is the most common notifiable sexually transmitted infection (STI) in Sweden. A mutated Chlamydia, nvCT, has contributed to the increase. The occurrence of repeat infections is not investigated in Sweden. The current paper presents the study protocol for the first Swedish clinical investigation of repeat Chlamydial infection. The concern of the study is whether a Chlamydia infection at inclusion indicates an increased risk for Chlamydia at follow-up after 6-8 months, gender-specific risk factors for and clinical presentation of repeat infections.METHODS AND DESIGN:Sesam City is a drop-in clinic in the city centre of Stockholm. Patients 20 years and older are admitted. During 2007, the clinic had 15,000 visits, 60% made by men. In December 2007, a cohort study began, and data collection was finished in April 2009. A total of 2,813 study participants aged 20-39 years were recruited. Data collection included an anonymous self-administered paper-and-pen questionnaire on sexual behaviour, reproductive health and history of Chlamydia, and condom use. Chlamydia tests were performed by self-sampled specimens, analyzed by the ProbeTec (Becton Dickinson) method, Ct-positive specimens also analyzed with a nvCT-specific method. Data from medical records were summarized in clinical report forms. Patients positive for Chlamydia were retested 4 weeks after treatment. Contact tracing covered sexual contacts during the last 12 months. At follow-up 6-8 months after inclusion, Chlamydia tests were performed, and a new questionnaire and CRF completed.DISCUSSION:A STI-clinic-based prospective cohort study allowed us to survey 2813 adult patients. The collected data will provide gender-specific information on the occurrence of and risk for repeat Chlamydia infection, the occurrence of nvCT, and clinical data and information on sexual behaviour and reproductive health, risk-taking and condom use.

Background: In 2006, a genetic variant of Chlamydia trachomatis not detectable with the most commonly used diagnostic tests was identified. Initial reports suggested that as many as 10% to 13% of all chlamydia cases would have remained undiagnosed. The aim of the study was to find the occurrence and clinical findings of this genetic variant among a high-risk population in Stockholm, Sweden. Methods: Samples were analyzed using the Cobas TaqMan CT test (Roche Diagnostics). To detect the new variant, an additional PCR-analysis, artus C. trachomatis LC MOMP PCR Kit (Qiagen) was performed on all negative samples. Positive results in the artus test were confirmed by a mutant specific PCR. Clinical data were retrospectively collected from medical records. Results: Among 1009 samples analyzed, 115 were positive for C. trachomatis and among those, 27 were found to belong to the genetic altered strain. This variant constituted 23% of all chlamydia cases diagnosed, and 29% were found in the age group 20 to 29 years. Women with the new variant were younger and had more often performed another chlamydia test within the previous 6 months compared with those infected with the wild type. Conclusion: These results indicate that a large number of sexually active individuals might be infected despite a negative chlamydia test, thus facilitating a rapid transmission of the new variant. Accordingly, it is of great importance to be aware of limitations of the diagnostic methods used.

Vulvar vestibulitis is a major cause of entry dyspareunia in young women. The aim of this study was to evaluate a self-reported history of bacterial vaginosis, candidiasis, use of oral contraception and nulli-pregnancy as risk factors for vestibulitis. A retrospective examination of medical records was performed for 45 patients with vestibulitis from a vulvar clinic in Oslo, median age 24 years, age range 19-49 years. Four controls per case were selected randomly from the same Oslo source population as the cases. Age-matching was not performed, as matching does not control for confounding in the case-control design. Controls anonymously answered a postal questionnaire, response rate 61%. The crude effect for the major potential predictors for vulvar vestibulitis was estimated, and stratification on age for the major potential predictors. The method of Mantel Haenszel was used to quantify confounders, and control for multi-confounders and the gradient effect of different covariates was performed. The major confounder was age. Independent risk factors for vestibulitis were nulli-pregnancy, odds ratio (OR) 8.4 (95% confidence interval (CI) 2.8-25.2) and bacterial vaginosis, OR 3.37 (95% CI 1.06-10.6). Adjusting for age diluted the effect of oral contraception and frequent treatment for candidiasis. This study is the third case-control study identifying bacterial vaginosis as a risk factor for vestibulitis. Thus, it remains to be investigated whether abnormal vulvo-vaginal microbiota belongs to the aetiology of vulvar vestibulitis.