Chlamydia trachomatis and Neisseria gonorrhoeae are established causes of pelvic inflammatory disease (PID), but up to 70% of cases with PID have neither infection detected. We determined the prevalence of and trends in Mycoplasma genitalium and bacterial vaginosis (BV) detection among women with non-C. trachomatis/N. gonorrhoeae PID to inform testing and treatment strategies.
We conducted a retrospective case series to determine the number of cases with PID (defined by presence of a minimum of uterine, adnexal or cervical motion tenderness) with C. trachomatis, N. gonorrhoeae, M. genitalium and/or BV detected between 2014 and 2024 at Melbourne Sexual Health Centre (MSHC). We examined trends in testing and detection of each infection over time and, among cases with PID tested for all four infections, determined the proportion with each infection detected.
There were 3000 cases with PID during the study period. Over the 11 years, the proportion of cases with PID tested for C. trachomatis and N. gonorrhoeae was stable and high, with rises in their detection (range=7%–19%, Ptrend=0.021; 1%–7%, Ptrend<0.001, respectively). Both the proportion tested for BV and M. genitalium (89%–95%, 91%–97%, Ptrend=<0.001, respectively) and with BV and M. genitalium detected (22%–37%, 6%–14%, Ptrend<0.001, respectively) significantly increased over time. Among 2557 (85%) cases tested for all four infections, 927 (36%) had 1 and 256 (10%) had >1 infection detected. Among 2149 (84%) non-C. trachomatis/N. gonorrhoeae cases with PID, 26% had BV, 6% had M. genitalium and 4% were co-infected with BV and M. genitalium; >50% had none of the infections detected.
In this retrospective study of cases with PID attending MSHC between 2014 and 2024, C. trachomatis and/or N. gonorrhoeae were detected in <20% of all cases. Among non-C. trachomatis/N. gonorrhoeae cases with PID, BV and M. genitalium detection was common and increased over time. Prospective case-control and sequencing studies are needed to determine the aetiologic contribution of BV, M. genitalium and other additional candidate organisms to PID.