Occurrence of pharyngeal Chlamydia trachomatis is uncommon in patients with a suspected or confirmed genital infection

Abstract Objective. To evaluate how common pharyngeal Chlamydia trachomatis (CT) is among mainly heterosexual women and men with a confirmed or a highly suspicious genital infection having had recent unprotected active oral sex. Design. Prospective observational study. Setting. Out-patient clinics for sexually transmitted infections in Stockholm. Population. A total of 143 women and 138 men with a confirmed or suspected genital CT infection and a history of active oral sex. Methods. Pharyngeal samples from men and women in the study population were analyzed for the presence of CT. Main outcome measures. Number of positive CT in pharyngeal samples in relation to positive CT in genital samples. Results. Of the women, 9/128 (7.0%) were positive in the pharyngeal samples. None were exclusively positive in the pharynx. Three of 110 men (2.7%) had pharyngeal involvement. One man was positive in the pharynx as well as in the urine sample, and two men were exclusively pharyngeal CT positive. Conclusions. The finding of CT in the pharynx is not common in spite of the presence of a genital infection and a history of active oral sex.