Detection of macrolide resistance in Mycoplasma genitalium in France.

OBJECTIVES: Mycoplasma genitalium is a sexually transmitted organism associated with non-gonococcal urethritis in men and several inflammatory reproductive tract syndromes in women. Resistance to macrolides has been recently associated with point mutations in the 23S rRNA gene. The aim of this study was to detect these mutations using a large French collection of M. genitalium-positive specimens. We evaluated whether these mutations were related to azithromycin treatment failure and whether macrolide-resistant M. genitalium may be spreading.

PATIENTS AND METHODS: A retrospective study conducted in France between 2003 and 2010 included 156 urogenital clinical specimens from 136 patients that were positive for M. genitalium. Mutations in domain V of M. genitalium 23S rRNA were detected using amplification and sequencing. The mutated strains were genotyped by studying single nucleotide polymorphisms in the mgpB gene.

RESULTS: We have detected macrolide resistance-associated mutations in M. genitalium since 2006 at a rate of 13.2%, ranging from 10% to 15.4% of patients per year. Nine mutations at position 2059 as well as two A2058G substitutions, one A2062T substitution and one C2038T substitution (Escherichia coli numbering) were identified in M. genitalium. These patients had treatment failure with azithromycin in 75% (6/8) of cases. For one patient, genotyping showed selection for the mutation during treatment with azithromycin.

CONCLUSIONS: For the first time, we describe macrolide resistance for M. genitalium in France and demonstrate that its detection has increased since 2006. Epidemiological surveillance of M. genitalium is necessary to adapt treatments to M. genitalium infections.