Persistence of Chlamydia trachomatis infection detected by polymerase chain reaction in untreated patients

Background. Prior studies have used Chlamydia trachomatis culture methods to demonstrate both persistence and spontaneous clearance of genital C trachomatis infection. Objective: To further assess the issue of persistence and spontaneous clearance of C trachomatis infection, untreated men and women were evaluated with repeated polymerase chain reaction (PCR) testing. Methods: Ninety four untreated patients with a prior positive C trachomatis PCR test returning to the Denver Metro Sexually Transmitted Disease Clinic were retested by PCR. Results: The median and range intervals from initial to follow-up testing were 9.0 (2-112) days for men and 10.0 (2-231) days for women. Repeated PCR tests were positive for 29 of 36 men (80.6%) and 45 of 58 women (77.6%). Persistent PCR positivity did not decrease with a longer testing interval. By multivariate analysis, independent predictors of a persistently positive PCR test included nonwhite ethnicity, an interval of more than 3 days since last sexual encounter before the initial test, and an initial PCR optical density value of greater than or equal to 3.0. Conclusions: In the absence of treatment, a large majority of patients testing positive for C trachomatis by PCR are likely to remain positive for variable periods of time, increasing the risk of transmission and immune-mediated damage. A low initial optical density value and recent sexual contact may be markers for exposure that does not establish infection.