Macrolide Resistance in the Aerococcus urinae Complex: Implications for Integrative and Conjugative Elements

Area of Science:

• Microbiology
• Genetics
• Antimicrobial Resistance

Background:

• Aerococcus urinae complex (AUC) is an emerging uropathogen with poorly understood disease spectrum and resistance.
• Growing concerns necessitate investigation into AUC's antibiotic resistance profiles, particularly macrolide resistance.

Purpose of the Study:

• To determine the prevalence of macrolide resistance in urinary AUC isolates.
• To elucidate the genetic mechanisms underlying macrolide resistance in AUC.

Main Methods:

• Phenotypic antimicrobial susceptibility testing on 189 urinary AUC isolates.
• Genomic analysis to identify resistance genes and mobile genetic elements.
• Comparative genomics of AUC isolates and related pathogens.

Main Results:

• 45% of AUC isolates exhibited macrolide resistance.
• The macrolide resistance gene ermA was identified on integrative and conjugative elements (ICEs).
• High sequence homogeneity of ICEs across related pathogens suggests potential for cross-species resistance dissemination.

Conclusions:

• Horizontal gene transfer via ICEs is a likely mechanism for macrolide resistance in AUC.
• Understanding AUC resistance mechanisms is vital for surveillance and antibiotic stewardship.
• Community-level surveillance is needed to combat urinary microbiome resistance spread.