Macrolide and fluoroquinolone associated mutations in Mycoplasma genitalium in a retrospective study of male and female patients seeking care at an STI Clinic in Guangzhou, China, 2016-2018.

Abstract

BackgroundAntimicrobial resistance in M. genitalium is a growing clinical problem. We investigated the presence of mutations for macrolide and fluoroquinolone, two commonly used medical regiments for treatments in China. Our aim is to analyze the prevalence and diversity of mutations among M. genitalium-positive clinical specimens in Guangzhou, Guangdong, south China.MethodsA total of 154 stored M. genitalium positive specimens from men and women attending an STI clinic were tested for macrolide and fluoroquinolone mutations. M. genitalium was detected via TaqMan MGB real-time PCR with a sensitivity of five genome equivalents (geq)/reaction. Mutations associated with macrolide resistance were detected using primers targeting region V of the 23S rRNA gene. Fluoroquinolone resistant mutations were screened via primers targeting topoisomerase IV (parC) and DNA gyrase (gyrA).Results98.7% (152/154), 95.5% (147/154) and 90.3% (139/154) of M. genitalium positive samples produced sufficient amplicon for detecting resistance mutations in 23S rRNA, gyrA and parC genes, respectively. 66.4% (101/152), 0.7% (1/147) and 77.7% (108/139) samples manifested mutations in 23S rRNA, gyrA and parC genes, respectively. A2072G (59/101, 58.4%) and S83I (79/108, 73.1%) were highly predominating in 23S rRNA and parC genes, respectively. Two sample had amino acid alteration in gyrA (M95I and A96T, respectively). Two sample had two amino acid alterations in parC (S83I + D87Y). 48.6% (67/138) samples harbored both macrolide and fluoroquinolone resistance-associated mutations. The most common combination of mutations was A2072G (23S rRNA) and S83I (parC) (40/67, 59.7%). One sample had three amino acid changes in 23S rRNA, gyrA and parC genes (A2072G + A96T + S83I).ConclusionsThe high antimicrobial resistance rate of M. genitalium shows a worrisome trend in Guangzhou and suggests antimicrobial resistance testing and the development of new antibiotic regimens are crucial.