Chlamydia trachomatis genotype distribution and other sexually transmitted coinfections in subjects attending a STD Outpatients Clinic in Italy.

Chlamydia trachomatis genotype distribution and other sexually transmitted coinfections in subjects attending a STD Outpatients Clinic in Italy. Foschi C. 1, Russo I. 1, Entrocassi A. C. 2, Marangoni A.1, Ostanello F.3, D’Antuono A.4, Bellavista S. 4, Trimarco R. 4, Nardini P. 1, Cevenini R.1 1Section of Microbiology-DESOS, 3Dipartimento di Scienze Mediche Veterinarie, and 4Dipartimento di Med. Interna, Dell’invecchiamento e Malattie nefrologiche, University of Bologna, Bologna, Italy 2Area Inmunología Clinica. Dept. Bioquimica Clinica. Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina. INTRODUCTION Chlamydia trachomatis (CT) urogenital infections are the most commonly reported bacterial sexually transmitted diseases. Many patients remain asymptomatic and develop persistent infections which can lead to severe reproductive sequelae. The gene encoding the major outer membrane protein (MOMP), omp1, has been widely used for CT molecular epidemiology, with a variety of molecular techniques such as PCR-RFLP, RT-PCR, or nested PCR followed by sequencing. Genotyping of CT strains is important to monitor contact tracing, to enable association with clinical manifestations or pathogenicity and may play a role in developing strategies for vaccine design. The aim of this study was to investigate CT genotype distribution in a non-selected STD population. METHODS In the period between 1 January 2011 and 31 December 2011 we enrolled 1076 consecutive patients attending the STD Outpatients Clinic of St. Orsola University Hospital of Bologna, Italy. Subjects eligible for the study were at least 18 years old, sexually active and met one or more of the following criteria: seeking treatment for STD-related symptoms, seeking STD screening or reported unsafe sex practice with an infected partner. A urine specimen for DNA detection of Chlamydia trachomatis and Neisseria gonorrhoeae (GC) by VERSANT CT/GC DNA 1.0 Assay (Siemens Healthcare Diagnostics) and a blood sample, for HIV and syphilis serological testing, were obtained from each patient. In case of a CT positive result by VERSANT CT/GC DNA 1.0 Assay, we collected the corresponding remnant DNA extract and used it as a template for omp1 semi-nested-PCR. The omp1 gene was amplified using the methodology describe by Lan (1), with slight modifications (2). RFLP analysis of PCR-positive samples was carried out as described by Sayada et al. (2-3), using the semi-nested PCR product of approximately 1-Kbp. Briefly, 10 μl of the nested PCR product was digested with 2.5 U of AluI (Promega). Depending on the AluI pattern, amplified samples were analyzed, if necessary, with HinfI, DdeI or EcoRI (Promega) according to the manufacturer’s instructions. Genotypes were identified by their restriction patterns on ethidium bromide stained 12% polyacrylamide gel electrophoresis. A P value of <0.05 was considered statistically significant. RESULTS Total prevalence of CT infection was 11.5% (124 of 1076 patients), with no significant differences between men (12.5%; 67 positives out of 535) and women (10.5%; 57 positives out of 541). Regarding age of CT positive subjects, we noticed that the prevalence of CT infection was much higher in females younger than 29 years compared to women over 30 (P<0.01). No significant differences were noticed in male patients. Clinical symptoms related to CT infection were present more frequently in infected males than in infected females (77% vs. 50%). Prevalence of CT infection didn’t show significant variations in subjects having different sexual orientation; on the contrary, GC prevalence was much higher in men having sex with men-MSM (17.9%) than in men having sex with women-MSW (5.2%) (P<0.01). CT/GC coinfection was present only in male patients (11.9% of CT infected men) and not in females (P<0.01). MSM showed significantly more co-infections than MSW (P<0.01). The most common CT genotype in our population was E,...