Mycoplasma genitalium is an under-recognized but important contributor to the STI epidemic in the United States. Bacterial STIs are concentrated among men who have sex with men (MSM), and disproportionately affect those living with HIV or on PrEP. Studies outside of the U.S. have demonstrated a substantial burden of asymptomatic M. genitalium in MSM. U.S. data on asymptomatic M. genitalium prevalence are limited, with a single study of MSM living with HIV showing urogenital and rectal prevalence of 10.8% and 6.4%, respectively. M. genitalium causes nongonococcal urethritis (NGU) in men as well as cervicitis and PID in women and has been associated with an increased risk of HIV acquisition. Asymptomatic M. genitalium carriage may serve as a reservoir for future infection and drive the development of drug resistance when antibiotics are administered for other indications. Management of M. genitalium infections is impeded by rising rates of antibiotic resistance to the current first line antibiotic azithromycin and to quinolones, resulting in high rates of treatment failure. Studies have demonstrated that lower bacterial load is associated with greater likelihood of clinical cure, prompting the development of sequential treatment algorithms to reduce bacterial burden with initial therapy while resistance testing is conducted.
This pilot study will estimate the prevalence of M. genitalium infection and antibiotic resistance in a cohort of high risk MSM and transgender women (TGW) who have HIV or use PrEP and are enrolled in an ongoing clinical trial of doxycycline post-exposure prophylaxis for STI reduction. We will examine resistance to azithromycin and quinolones, as many resistance studies have been done in other countries, where patterns of antibiotic use and resistance may not be generalizable to the U.S. We will measure the median number of genome copies of M. genitalium, as bacterial load may affect the likelihood of curative treatment.