Viability of Chlamydia trachomatis in Different Anatomical Sites—a Systematic Review and Meta-analysis

Abstract

Abstract Background Modern assays for the detection of Chlamydia trachomatis (CT) rely on nucleic acid amplification testing (NAAT) of DNA or ribosomal RNA. However, it is also known that both viable (“living”) and non-viable (“dead”) CT can be detected by NAAT. Multiple laboratory techniques to measure CT viability have emerged. Methods We searched PubMed, EMBASE, Scopus, and Dimensions as well as conference abstracts for entries between January 2000 and May 2023. We included any studies that measured CT viability among NAAT-positive samples. Viability assays include enhanced cell culture, direct fluorescent antibody (DFA), messenger RNA (mRNA) detection via digital droplet polymerase chain reaction (PCR, ddPCR), viability PCR (V-PCR), and real-time PCR measuring RNA-to-DNA ratio (RDR) (eg, InSignia®). A meta-analysis was performed on the proportions of non-viable CT by anatomical site. Results We screened 31 342 records and included 16 studies in the analysis. The pooled proportions of non-viable CT by site were: 33% (95% confidence interval [CI]: 19%–47%) in rectal swabs (8 studies), 17% (95% CI: 7%–27%) in cervical swabs (6 studies), 15% (95% CI: 6%–25%) in vaginal swabs (6 studies), and 11% (95% CI: 9%–17%) in urine/urethral swabs (2 studies). Conclusions All included studies found that a proportion of NAAT-detected CT is non-viable. The findings have far-reaching implications for screening programs and studies evaluating new STI tests and antimicrobial regimens.