Antimicrobial Resistance Phenotypes and Genotypes of Escherichia coli Isolates from Artisanal Minas Frescal Cheeses from the Federal District, Brazil

<b>Background/Objectives:</b> This study characterized the phenotypic and genotypic profiles of antimicrobial resistance in 104 <i>Escherichia coli</i> isolates obtained from 22 samples of artisanal Minas Frescal cheese from the Federal District, Brazil. <b>Methods</b>: The antimicrobial susceptibility of <i>E. coli</i> isolates was assessed using the disk diffusion method and antimicrobial resistance genes were detected using polymerase chain reaction methods with specific primers. <b>Results:</b> The highest rates of phenotypic antimicrobial resistance were observed for sulfonamides (85.58%, 89/104) and tetracyclines (38.46%, 40/104). In the genotypic profiles, most <i>E. coli</i> isolates carried the sulfonamide resistance genes <i>sul1</i>/<i>sul2</i> (62.50%, 65/104), tetracycline resistance genes <i>tetA</i>/<i>tetB</i> (65.38%, 68/104), and β-lactam resistance genes <i>blaCTX-M</i>/<i>blaTEM</i>/<i>blaSHV</i> (55.77%, 58/104). Most <i>E. coli</i> strains that presented sulfonamide resistance genes carried the <i>sul1</i> gene (49.04%, 51/104) and were phenotypically sulfonamide-resistant strains (59.61%, 62/104). Regarding the <i>E. coli</i> strains that carried tetracycline resistance genes, the majority harbored both <i>tetA</i> and <i>tetB</i> genes (34.61%, 36/104), with 35.56% (37/104) being phenotypically resistant and 29.80% (31/104) being phenotypically susceptible. For <i>E. coli</i> strains that presented β-lactam resistance genes, the most frequently detected gene was <i>blaCTX-M</i> (21.15%, 22/104) and, notably, most <i>E. coli</i> strains (43.26%, 45/104) were phenotypically susceptible. The <i>cat1</i> and <i>clmA</i> genes (associated with phenicol resistance) were detected in 22.12% of the <i>E. coli</i> isolates (23/104), with only two strains (1.92%) being phenotypically resistant to chloramphenicol. <b>Conclusion:</b> The high prevalence of <i>E. coli</i> carrying antimicrobial resistance genes in artisanal cheese raises public health concerns regarding the dissemination of potentially pathogenic antimicrobial-resistant microorganisms through the food chain.