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.