Dynamics and virulence of Enterobacteriaceae reservoirs harboring bla(CTX-M) group 1 in community wastewater.

High levels of bla CTX-M group 1 genes are present in untreated community wastewater influent, with concentrations only 1-2 log lower than expected and not linked to human fecal markers.

• Why it matters: Understanding environmental reservoirs of antimicrobial resistance genes like bla CTX-M group 1 is crucial because they can harbor potentially pathogenic bacteria and influence the spread of resistance beyond clinical settings.
• What they did: The study analyzed 268 wastewater samples from four WWTPs using molecular and culture methods, revealing high diversity of bla CTX-M group 1 genes, predominantly in E. coli, K. pneumoniae, and other Enterobacteriaceae, with isolates resembling clinical strains.
• The result: Findings suggest wastewater reservoirs contain potentially pathogenic, resistant bacteria similar to clinical strains, emphasizing the importance of monitoring environmental reservoirs to understand and mitigate antimicrobial resistance transmission.