Prevalence of Chlamydia trachomatis Infection, Serovar Distribution and Co-Infections with Seven High-Risk HPV Types among Italian Women with a Recent History of Abnormal Cervical Cytology

Chlamydia trachomatis (Ct) and human papillomavirus (HPV) are the most prevalent sexually transmitted infections throughout the world. Despite the serious complications associated with chronic Ct infections in sexually active women, a screening program is not yet available in Italy. Moreover, HPV/Ct co-infections are also known to occur frequently, increasing the risk of HPV-induced carcinogenesis. The aim of this study was to evaluate the prevalence of Ct infections, the distribution of Ct serovars, and the incidences of Ct/HPV co-infections among women with a recent history of abnormal cervical cytology. Cervical samples were collected from 199 women referred for a gynecological visit following an abnormal Pap test results. All samples were tested for the presence of Ct and HPV DNA using real-time PCR assays; Ct typing of positive samples was performed by PCR-RFLP (restriction fragment length polymorphism) targeting the ompA gene. A high percentage of these women (12.8% and 21.7% with or without abnormal cytology on "retesting", respectively) were found to be Ct positive. Serovar F was the most prevalent type in Ct positive women, followed by E and K. Ct/HPV co-infections were detected in 7% (14/199) of enrolled women, with HPV-16, HPV-51, and HPV-52 being most frequently identified in co-infections. This study provides new epidemiological data on the prevalence of Ct and associated HPV infection in women with a recent history of abnormal cervical cytology in Italy, where notification of cases is not mandatory.