Spontaneous clearance of Chlamydia trachomatis accounting for bacterial viability in vaginally or rectally infected women (FemCure)

What is it about?

Objectives.
Spontaneous clearance of Chlamydia trachomatis (CT) infections can occur between diagnosis and treatment. We followed CT patients to assess clearance of CT-DNA, using routine quantitative polymerase chain reaction (PCR) methods. We also explored the clearance definition to account for clearance of viable CT, assessed by viability polymerase chain reaction (V-PCR) testing.
Methods.
Three outpatient STI-clinics included CT diagnosed women (Netherlands, 2016-2017, FemCure); participants had vaginal (vCT) and rectal (rCT) CT (group A, n=155), vCT and rectally untested (group B, n=351), single vCT (group C, n=25), or single rCT (group D, n=29). Follow-up (median interval 9 days) vaginal and rectal samples underwent quantitative polymerase chain reaction (PCR) testing (detecting total CT-DNA). When PCR positive, samples underwent V-PCR testing to detect ‘viable CT’ [CT-DNA from intact CT organisms; V-PCR positive]). ‘Clearance’ was the proportion PCR negative patients and ‘clearance of viable CT’ the proportion of patients testing PCR-negative or PCR-positive but V-PCR-negative. We used multivariate logistic regression analyses to diagnosis group (A-D), age, days since initial CT test (diagnosis), and study site [STI clinic] in relation to clearance and clearance of viable CT.
Results.
Clearance and clearance of viable CT at both anatomic sites were respectively for (A) 0.6%, 3.9% (B) 5.4%, 9.4%, (C) 32.0%, 52.0%, (D) 27.6%, 41.4%. In multivariate analyses, women with single infections (groups C and D) had higher likelihood of clearance than women concurrently infected with vCT and rCT (p<0.001).
Of rectally untested women (group B), 76.9% had total CT-DNA and 46.7% had viable CT (V-PCR positive) at the rectal site.
Conclusions.
Of untreated female vCT patients who had CT also at the rectal site, or who were rectally untested, only small proportion cleared CT (in fact many had viable CT) at their follow-u visit (median 9 days). Among single site infected women clearance was much higher.

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