Use of viability PCR for detection of live Chlamydia trachomatis in clinical specimens

Background The current testing approach to diagnose Chlamydia trachomatis (CT) infection relies on nucleic acid amplification tests (NAATs). These are highly sensitive, but do not distinguish between active and residual bacterial which may remain after resolution of infection, or via cross-contamination. Better methods assess the viability CT detected in clinical samples would be useful determining relevance detection a variety settings. goal this study was test PCR (vPCR) as method viable bacteria from non-viable CT. Methods vPCR propidium monoazide dye (PMAxx), intercalates into accessible DNA dead organisms prevents their assay for ompA gene. We used digital quantify absolute genome copy numbers samples. validated using laboratory stocks with known viability. Then, we tested total DNA, culture results 18 vaginal specimens 25 rectal specimens, all had positive by NAAT. Results In CT, defined ratios heat-killed live tracked closely expected results. were correlated, though genomes outnumbered 2.2–52.6-fold more copies. As expected, than Both correlated (Spearman correlation R = 0.8425 0.8056 vPCR). Ten NAAT negative PCR, vPCR, inconclusive culture. Of 6 that positive, positive. additionally 8 + negative, levels very low (mean 1,357 copies/ml) Conclusions is fast easy PCR. Inconsistent suggest amount varies considerably specimens. many fact represent replicating bacteria, likely result significant overuse unnecessary antibiotics.