Macrolide and fluoroquinolone resistance-associated mutations in Mycoplasma genitalium in Johannesburg, South Africa, 2007-2014

Background: Antimicrobial resistance in Mycoplasma genitalium is rising globally with resultant clinical treatment failure. We investigated the prevalence of mutations in the macrolide and fluoroquinolone resistance-determining regions of M. genitalium in Johannesburg, South Africa, and ascertained their association with HIV serostatus. Methods: Stored M. genitalium positive specimens, collected from STI and HIV patients enrolled in the Gauteng STI National Microbiological Surveillance programme (2007-2014) and a large HIV outpatient clinic-based study (2007) in Johannesburg, were tested for antimicrobial resistance. Results: We determined the prevalence of 23S rRNA gene mutations conferring macrolide resistance and mutations in the quinolone resistance-determining regions (QRDR) of the gyrA and parC genes in 266 M. genitalium positive DNA extracts. No macrolide resistance-associated mutations were detected in any of the specimens analysed. QRDR mutations with known M. genitalium-associated fluoroquinolone resistance were not detected in gyrA, however, one specimen (0.4%) contained a D87Y amino acid alteration in parC, which has been linked to fluoroquinolone treatment failure. The most common parC amino acid change detected, of unknown clinical significance, was P62S (18.8%). We found no significant association between QRDR mutations in M. genitalium and HIV-infection. Conclusions: Ongoing antimicrobial resistance surveillance in M. genitalium is essential, as macrolide resistance may emerge given the recent incorporation of azithromycin into the 2015 South African national STI syndromic management guidelines.