Mycoplasma genitalium antibiotic resistance-associated mutations in genital and extragenital samples from men-who-have-sex-with-men attending a STI clinic in Verona, Italy.

Mycoplasma genitalium (MG) is one of the most warning emerging sexually transmitted pathogens also due to its ability in developing resistance to antibiotics. MG causes different conditions ranging from asymptomatic infections to acute mucous inflammation. Resistance-guided therapy has demonstrated the best cure rates and macrolide resistance testing is recommended in many international guidelines. However, diagnostic and resistance testing can only be based on molecular methods, and the gap between genotypic resistance and microbiological clearance has not been fully evaluated yet. This study aims at finding mutations associated with MG antibiotic resistance and investigating the relationship with microbiological clearance amongst MSM. From 2017 to 2021, genital (urine) and extragenital (pharyngeal and anorectal swabs) biological specimens were provided by men-who-have-sex-with-men (MSM) attending the STI clinic of the Infectious Disease Unit at the Verona University Hospital, Verona, Italy. A total of 1040 MSM were evaluated and 107 samples from 96 subjects resulted positive for MG. Among the MG-positive samples, all those available for further analysis (n=47) were considered for detection of mutations known to be associated with macrolide and quinolone resistance. 23S rRNA, gyrA and parC genes were analyzed by Sanger sequencing and Allplex™ MG and AziR Assay (Seegene). A total of 96/1040 (9.2%) subjects tested positive for MG in at least one anatomical site. MG was detected in 107 specimens: 33 urine samples, 72 rectal swabs and 2 pharyngeal swabs. Among them, 47 samples from 42 MSM were available for investigating the presence of mutations associated with macrolide and quinolone resistance: 30/47 (63.8%) showed mutations in 23S rRNA while 10/47 (21.3%) in parC or gyrA genes. All patients with positive Test of Cure (ToC) after first-line treatment with azithromycin (n=15) were infected with 23S rRNA-mutated MG strains. All patients undergoing second-line moxifloxacin treatment (n=13) resulted negative at ToC, even those carrying MG strains with mutations in parC gene (n=6). Our observations confirm that mutations in 23S rRNA gene are associated with azithromycin treatment failure and that mutations in parC gene alone are not always associated with phenotypic resistance to moxifloxacin. This reinforces the importance of macrolide resistance testing to guide the treatment and reduce antibiotic pressure on MG strains.

Sandri A ，Carelli M ，Visentin A ，Savoldi A ，De Grandi G ，Mirandola M ，Lleo MM ，Signoretto C ，Cordioli M ... -  《Frontiers in Cellular and Infection Microbiology》

Prevalence of Mycoplasma genitalium infection with antimicrobial resistance mutations among gay sex workers in China.

Wang L ，Li Z ，Wan C ，Tian X ，Liu H ，Li Y ... -  《-》

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.

Ke W ，Li D ，Tso LS ，Wei R ，Lan Y ，Chen Z ，Zhang X ，Wang L ，Liang C ，Liao Y ，Chen H ，Liu Y ，Zheng H ，Yang L ... -  《BMC INFECTIOUS DISEASES》

Fluoroquinolone and macrolide resistance-associated mutations in Mycoplasma genitalium.

Tagg KA ，Jeoffreys NJ ，Couldwell DL ，Donald JA ，Gilbert GL ... -  《-》

Prevalence of macrolide- and fluoroquinolone-resistant Mycoplasma genitalium strains in clinical specimens from men who have sex with men of two sexually transmitted infection practices in Berlin, Germany.

The cell-wall-less Mollicutes species Mycoplasma genitalium is a sexually transmitted micro-organism that causes different male and female genital tract infections. In recent years, resistance of the pathogen to macrolides and fluoroquinolones has been increasingly reported worldwide and is more frequent in risk groups. To determine the rates of antimicrobial resistance, M. genitalium strains in 195 specimens from 154 outpatients (154 first and 41 follow-up samples) treated in two specialised practices between September 2017 and December 2018 in Berlin, Germany, were analysed. The included patients were predominantly men who have sex with men (MSM) (91.6%) and were HIV-positive in many cases (49.4%). Only 27.3% of M. genitalium-positive patients reported symptoms. Among the first samples (mainly rectal swabs) (57.8%), mutations associated with macrolide (23S rRNA) and quinolone (parC gene) resistance were detected in 79.9% and 13.0% of strains, respectively. Resistance to both classes of antibiotics was found in 11.7% of specimens. Changes of A→G at position 2072 of 23S rRNA and of serine at position 83 of ParC were the most frequent alterations. Although azithromycin is recommended as a first-line antibiotic to treat infections with M. genitalium in MSM, according to these data its use must be highly limited in Berlin. Besides the need for resistance studies regarding strains circulating in other locations and among different patient groups in Germany, the results emphasise the importance of intensified antibiotic resistance testing of M. genitalium to avoid a further increase in treatment failures in infections with this emerging human pathogen.

Dumke R ，Ziegler T ，Abbasi-Boroudjeni N ，Rust M ，Glaunsinger T ... -  《-》