Background The initial culturing of Mycoplasma genitalium from clinical specimens is still difficult and the antimicrobial susceptibility data of M. genitalium strains have not been enough. Multidrug resistant M. genitalium strains including macrolide or fluoroquinolone-resistance are increasing and analysis of M. genitalium strains is important.

Methods M. genitalium strains were isolated from urinary sediment of M. genitalium-positive urine-specimens from Japanese man. The antimicrobial susceptibility testing was examined by the cell-culture method. The tested antimicrobials were azithromycin (AZM), clarithromycin (CLR), doxycycline (DOX), minocycline (MIN), ciprofloxacin (CIP), levofloxacin (LVX), moxifloxacin (MOX) and sitafloxacin (STFX).

Results Total 14 M . genitalium strains were isolated from Japanese patients. Four strains were isolated in 2003, and other 10 strains were isolated in 2017 and 2018. MIC50 and MIC90 were ≥16 mg/L and ≥16 mg/L for AZM, ≥16 mg/L and ≥16 mg/L for CLR, .5 mg/L and 1 mg/L for DOX, 0.25 mg/L and 0.5 mg/L for MIN, 8 mg/L and ≥16 mg/L for CIP, 4 mg/L and ≥16 mg/L for LVX, 1 mg/L and 4 mg/L for MOX and 0.125 mg/L and 0.5 mg/L for STFX, respectively. There was no macrolide-resistant strains in 2003, but 9 strains isolated in 2017 and 2018 were resistant to macrolide. Seven strains had high MICs more than 1 mg/L for MOX, but only one strain had high MIC 1 mg/L for STFX. Except for one strain which had MIC 2 mg/L for DOX, MICs of other strains for DOX or MIN were shown between 0.125 mg/L and 1 mg/L.

Conclusion Among 14 strain, 7 strains had high MICs for macrolide and MOX. In Japan, multidrug-resistant M. genitalium strains were increasing. Limitation of this study was that we tried to isolated M. genitalium strains form patients with treatment-failure cases by macrolide or fluoroquinolone in 2017 and 2018.

Disclosure No significant relationships.