Whole-Genome Sequencing and Antimicrobial Resistance Analysis of Enterotoxigenic Escherichia coli F5 and F5-F41 Strains Isolated from Neonatal Calves in Inner Mongolia, China

Simple Summary Enterotoxigenic Escherichia coli not only seriously harms the economic and healthy development of the cattle industry but also serves as a reservoir of various antibiotic resistance genes, posing a threat to human public health. This study analyzed the antibiotic resistance spectrum and mechanisms of two pathogenic bacteria. The results showed that both strains were multidrug-resistant, resistant to third-generation cephalosporins, fluoroquinolones, and aminoglycosides. Furthermore, both strains contained 11 classes of antibiotic resistance genes and 74 resistance genes related to various bacterial efflux pumps, including 4 families, across 5 resistance mechanisms in their chromosomes and plasmids. The emergence of multidrug-resistant strains limits clinical antibiotic treatment options, and the widespread dissemination of their resistance genes poses a potential threat to global public health. This underscores the urgent need for monitoring multidrug-resistant pathogens to further curb their emergence and spread.