Antimicrobial resistance and treatment failures in symptomatic and asymptomatic Mycoplasma genitalium infections in São Paulo, Brazil: Evidence from a cross-sectional study of sexual health clinic attendees
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OBJECTIVES
We aimed to describe the epidemiology, antimicrobial resistance pattern, and treatment outcomes of symptomatic and asymptomatic Mycoplasma genitalium (MG) infections in patients from a public HIV/STI clinic in São Paulo, Brazil.
METHODS
This cross-sectional study ran from July 2023 to September 2024. Patients tested for bacterial STIs were invited to participate by consenting to sample storage for resistance analysis. Clinical management followed standard care at the clinician’s discretion, and data were retrospectively analyzed. MG positive samples were analyzed for macrolide and quinolone resistance associated mutations, respectively in the region V of the 23s rRNA and the ParC genes, using Allplex Azi-R and Moxi-R assays (Seegene, Inc., Seoul, Korea).
RESULTS
MG prevalence was 12.5% (47/376) in the study population and 66.0% (31/47) were asymptomatic infections. Mutations associated with macrolide (MDRM) and quinolone resistance were detected in 78.8% (26/33) and 21.1% (8/38) of the MG-positive samples, respectively. MDRM were significantly more common among symptomatic than asymptomatic patients (100.0% (13/13) vs 65.0% (13/20); p=0.016). Among untreated asymptomatic patients, 50.0% (3/6) cleared the infection without antibiotics. Treatment for 39.5% (15/38) included single-dose azithromycin, according to current national guidelines. Treatment failures were more common in the symptomatic group (91.7% (11/12) vs 40.0% (6/15); p=0.005).
CONCLUSION
Macrolide and quinolone resistance were common in Mycoplasma genitalium samples from an STI clinic in São Paulo, Brazil, with frequent treatment failures among symptomatic patients. Current Brazilian guidelines should be urgently revised. Screening and treating asymptomatic MG cases may promote antimicrobial overuse without clear benefits, as spontaneous clearance may be common. Larger studies are needed to guide management and clarify the clinical relevance of asymptomatic MG infections.
KEY POINTS
What is already known on this topic
Mycoplasma genitalium is common in vulnerable populations and poses a risk to antimicrobial resistance worldwide.
What this study adds
Detection of high rates of macrolide and fluoroquinolone resistance in Mycoplasma genitalium in Brazil, along with frequent spontaneous clearance in asymptomatic cases.
How this study might affect research, practice or policy
Findings support an update of Brazilian treatment guidelines and highlight the need for further investigation into the clinical relevance and management of asymptomatic infections.
