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

Abstract

Background:Antimicrobial resistance inM. genitaliumis a growing clinical problem. We investigated the mutations associatedwith macrolide and fluoroquinolone resistance, two commonly used medical regimens for treatment in China. Our aim is toanalyze the prevalence and diversity of mutations amongM. genitalium-positive clinical specimens in Guangzhou, south China.Methods:A total of 154 storedM. genitaliumpositive specimens from men and womenattending a STI clinic were testedfor macrolide and fluoroquinolone mutations.M. genitaliumwas detected via TaqMan MGB real-time PCR. Mutationsassociated 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)andDNAgyrase(gyrA).Results:98.7% (152/154), 95.5% (147/154) and 90.3% (139/154) ofM. genitaliumpositive samples produced sufficientamplicon for detecting resistance mutations in 23S rRNA,gyrAandparCgenes, respectively. 66.4% (101/152), 0.7% (1/147)and 77.7% (108/139) samples manifested mutations in 23S rRNA,gyrAandparCgenes, respectively. A2072G (59/101,58.4%) and S83I (79/108, 73.1%) were highly predominating in 23S rRNA andparCgenes, respectively. Two samples hadamino acid substitutions ingyrA(M95I and A96T, respectively). Two samples had two amino acid substitutions inparC(S83I + D87Y). 48.6% (67/138) of 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 hadthree amino acid changes in 23S rRNA,gyrAandparCgenes (A2072G + A96T + S83I). Conclusions:The high antimicrobial resistance rate ofM. genitaliumin Guangzhou is a very worrying problem andsuggests that antimicrobial resistance testing and the development of new antibiotic regimens are crucially needed.