Antimicrobial resistant bacteria from Lerma River basin in Mexico

A cross-sectional study of 20 sites along the Lerma River basin, as well as the Lake Chapala, was carry out to evaluate the presence of antimicrobial resistance genes (ARGs). ARGs for beta-lactams, aminoglycosides and quinolones were detected by PCR in 59 environmental isolates identified by Sanger sequencing of the 16S rRNA gene. Representative genomes of MDR strains were sequenced by NGS. Citrobacter freundii, Escherichia coli and Serratia marcescens were the more predominant species identified, showing high variation in the number of isolates in the 20 sampled sites and high frequency of resistance to beta-lactams, quinolones and aminoglycosides. The genes blaCTX, qnrB, qnrS y aac(6')lb-cr genes were the most prevalent. C. freundii showed the highest frequency of MDR strains. Whole genome sequence showed that C. freundii and K. pneumoniae, showed a high number of shared virulence and antimicrobial resistance genes, but E. coli showed the highest number of unique genes.