High levels of macrolide resistance-associated mutations in Mycoplasma genitalium warrant antibiotic susceptibility-guided treatment

Abstract

Objectives: Mycoplasma genitalium is a sexually transmitted pathogen, and infection with it is usually treated with macrolides. Unfortunately, emerging resistance to the macrolides has been associated with mutations in region V of the 23S rRNA gene. The aim of this retrospective study was to describe the incidence of macrolide resistance-associated mutations in M. genitalium from patients in the Netherlands. Methods: All urogenital samples obtained from patients visiting a general practitioner or hospital in the east of the Netherlands that tested positive using the routine M. genitalium real-time PCR (February 2012-November 2014) were included. Following a PCR targeting the 23S rRNA gene, sequencing of the PCR fragments was performed to identify possible macrolide resistance-associated mutations. Results: Forty-eight of the 153 samples (31.4%) included in this study contained a mutation in the 23S rRNA gene. This was reduced to 44/146 (30.1%) if only samples from unique patients were included. The predominant mutations identified were A2058G (16/44; 36.3%), A2059G (14/44; 31.8%) and a unique high proportion of A2058T (12/44; 27.3%). Treatment failure was observed in four patients initially infected with M. genitalium containing macrolide resistance-associated mutations, while in one of these patients subsequent treatment with moxifloxacin resulted in a microbiological cure. Conclusions: This study shows that macrolide resistance-associated mutations in M. genitalium occur with a high frequency. In contrast to studies from other regions, Dutch M. genitalium isolates carry the A2058T mutation at high frequency. Our data confirm the need for prospective detection of macrolide resistance-associated mutations prior to treating patients.