Emergence of clinical strains of Mycoplasma genitalium harbouring alterations in ParC associated with fluoroquinolone resistance

Surveillance for antimicrobial resistance in Mycoplasma genitalium clinical strains is extremely limited as culturing of strains from clinical specimens is still difficult. We therefore conducted a non-cultural assessment of fluoroquinolone resistance of M. genitalium clinical strains by analysing the quinolone-resistance determining regions (QRDRs) of the gyrA and parC genes. The QRDRs amplified from M. genitalium DNA taken from urine specimens of 28 men with non-gonococcal urethritis positive for M. genitalium by polymerase chain reaction were sequenced. An amino acid change (Phe-108→Iso) in GyrA was found in one specimen, and the same change was accompanied by an amino acid change (Lys-97→Arg) in ParC in another specimen. A single amino acid change (Ser-83→Asn, Asp-87→Tyr or Asp-87→Val) in ParC was also found in three other respective specimens without alterations in GyrA. No alterations in GyrA and ParC were found in the remaining 23 specimens. The alterations of Ser-83→Asn, Asp-87→Tyr and Asp-87→Val in ParC found in 3 (10.7%) of 28 specimens were analogous to those commonly observed in fluoroquinolone-resistant mutants of other Mycoplasma and Ureaplasma spp. M. genitalium harbouring mutations associated with fluoroquinolone resistance in the parC gene may have emerged clinically and the prevalence may be ca. 10% in Japan.