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

We studied prevalence of Chlamydia trachomatis (CT) urogenital infection and distribution of different genotypes in a non-selected STD population of 1625 patients, evaluating presence of coinfections with other sexually transmitted diseases. Each patient was bled in order to perform serological tests for syphilis and HIV, then urethral or endocervical swabs were obtained for the detection of CT and Neisseria gonorrhoeae by culture. DNA extracted from remnant positive swabs was amplified by omp1 Nested PCR and products were sequenced. Total prevalence of CT infection was 6.3% (103/1625), with strong differences between men and women (11.4% vs 3.9%, P<0.01). Clinical symptoms and presence of coinfections were much more frequent in men than in women (P<0.01). The most common serovar was E (prevalence of 38.8%), followed by G (23.3%), F (13.5%) D/Da (11.6%) and J (4.8%). Serovars distribution was statistically different between men and women (P=0.042), as well as among patients with or without coinfection (P=0.035); patients infected by serovar D/Da showed the highest coinfection rate. This study can be considered a contribution in increasing knowledge on CT serovar distribution in Italy. Further studies are needed to better define molecular epidemiology of CT infection and to investigate its correlation with other STDs.