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Objectives We determined the prevalence of macrolide and fluoroquinolone resistance-associated mutations in Mycoplasma genitalium DNA specimens from men with non-gonococcal urethritis (NGU) and analysed their effects on antibiotic treatments of M. genitalium infections. Methods In this retrospective study, we examined antibiotic resistance-associated mutations in the 23S rRNA, gyrA and parC genes of M. genitalium and the association of the mutations with microbiological outcomes of antibiotic treatments in men with M. genitalium-positive NGU. Results No macrolide resistance-associated mutations in the 23S rRNA gene were observed in 27 M. genitalium DNA specimens in 2011 and in 24 in 2012. However, 5 of 17 in 2013 had 23S rRNA mutations. Three of 15 in 2011, 6 of 19 in 2012 and 8 of 17 in 2013 had fluoroquinolone resistance-associated alterations in ParC. Three in 2013 had both the antibiotic resistance-associated alterations coincidentally. In two men with M. genitalium harbouring 23S rRNA mutations, the mycoplasma persisted after treatment with a regimen of 2 g of extended-release azithromycin (AZM-SR) once daily for 1 day. All nine men with mycoplasma harbouring ParC alterations were microbiologically cured with a regimen of 100 mg of sitafloxacin twice daily for 7 days. Conclusions Macrolide- or fluoroquinolone-resistant M. genitalium appears to be increasing, and the increase in fluoroquinolone-resistant mycoplasmas is especially remarkable in Japan. Mycoplasmas harbouring 23S rRNA mutations would be resistant to the AZM-SR regimen, but those harbouring ParC alterations would still be susceptible to the sitafloxacin regimen. [ABSTRACT FROM PUBLISHER]

We analyzed the 23S rRNA, gyrA and parC genes of Chlamydia trachomatis DNAs from men with urethritis and determined microbiological outcomes of an extended-release azithromycin (azithromycin-SR) regimen (2 g once daily for 1 day) and a sitafloxacin regimen (100 mg twice daily for 7 days) for chlamydial urethritis to clarify the macrolide and fluoroquinolone resistance status of clinical strains of C. trachomatis . We amplified the portions of 2 alleles of the 23S rRNA gene and the gyrA and parC genes from C. trachomatis DNAs in 284 first-voided urine specimens from men with chlamydial urethritis by PCR and sequenced their PCR products. We enrolled 369 men with chlamydial urethritis, comprising 314 and 55 treated with the azithromycin-SR regimen and the sitafloxacin regimen, respectively. Alleles 1 and/or 2 of the 23S rRNA gene were analyzed in 162 specimens. No mutations were found in the sequenced regions, including the central portion of domain V. The gyrA and parC genes were analyzed in 118 and 113 specimens, respectively. No amino acid changes were found within the quinolone resistance-determining region of the gyrA gene and in the sequenced region of the parC gene. The microbiological outcomes of the azithromycin-SR and sitafloxacin regimens were assessed in 176 and 30 men, respectively. The eradication rates were 96.0% (95% CI 93.1%–98.9%) for the azithromycin-SR regimen and 100% for the sitafloxacin regimen. Clinical strains of C. trachomatis with macrolide and/or fluoroquinolone resistance would be uncommon, and azithromycin or fluoroquinolone regimens could be recommended as treatments for chlamydial infections. [ABSTRACT FROM AUTHOR]

We observed fluoroquinolone treatment failures in 2 men with Mycoplasma genitalium -positive non-gonococcal urethritis in Japan. A fluoroquinolone regimen of sitafloxacin 100 mg twice daily for 7 days failed to eradicate M. genitalium . In both cases, M. genitalium had fluoroquinolone resistance-associated amino acid changes both in GyrA and ParC and a macrolide resistance-associated mutation in the 23S rRNA gene. The emergence of such multi-drug resistant strains can threaten antimicrobial chemotherapy for M. genitalium infections in Japan, because we will lose the first- (azithromycin) and second-line (sitafloxacin) antimicrobial agents to treat M. genitalium infections. We prescribed an extended minocycline regimen of minocycline 100 mg twice daily for 14 days for our patients, and the regimen was successful in eradicating the M. genitalium . The extended minocycline regimen might be an option that we can try when treating multi-drug resistant M. genitalium infections in clinical practice. [ABSTRACT FROM AUTHOR]