To determine whether Chlamydia trachomatis urogenital infections persist or relapse after antimicrobial therapy by serial measurement of chlamydial-specific DNA using the polymerase chain reaction (PCR), cell cultures, and serological studies.Design
Prospective evaluation of an inception cohort.Setting
University student health clinic.Participants
Twenty women with culture-proven and PCR-proven C trachomatis urogenital infections.Measurements
Incidence of persistent infection as determined by PCR, culture, and serial measurement of local and systemic antibody to C trachomatis for 5 months after doxycycline therapy.Results
Prior to therapy, C trachomatis was isolated in cell culture from the cervix in 19 of 20 women, from the urethra in 13 women, and from the rectum in 13 women. All culture-positive specimens were also PCR-positive. Immediately after completion of antimicrobial therapy, all women had negative cell cultures for chlamydia. Ten of 20 culture-negative cervical specimens and two culture-negative urethral specimens had chlamydial DNA present immediately after treatment. In addition, three women had detectable DNA from cervical specimens 1 week after treatment. The presence of cervicitis (P=.01), high inclusion counts (P=.004), and serological evidence of recent infection (P=.0004) were each significantly associated with PCR positivity after treatment. All 384 subsequent cervical, rectal, and urethral specimens collected over 5 months were negative by both PCR and culture with the exception of one woman who was reinfected. Serum immunoglobulin M (IgM) titers, geometric mean serum immunoglobulin G (IgG) titers, and prevalence of local antibody to chlamydia progressively declined after treatment.Conclusions
Standard antimicrobial therapy is effective in the long-term microbiologic eradication of uncomplicated C trachomatis urogenital infections. The presence of chlamydial DNA after antimicrobial therapy is of short duration and reflects excretion of nonviable organisms rather than persistent infection.