Phenotyping and genotyping studies on extended-spectrum β-lactamase-producing isolates from mastitic cows on dairy farms in Egypt.

BACKGROUND AND AIM

Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae have become a serious public health hazard worldwide. This importance is derived from the increase of new variants, particularly , , and genes. This study aimed to examine ESBL-producing isolated from different governorates in Egypt from dairy cows infected with subclinical and clinical mastitis.

MATERIALS AND METHODS

This study examined 207 milk samples for the resistance of isolates against 14 different antibiotics and ran serological identification of ESBL-producing isolates with complete antibiotic resistance. Genotypic and sequencing analyses of several resistance genes were conducted using a polymerase chain reaction.

RESULTS

was identified in cases with subclinical mastitis (80.5%) and clinical mastitis (85.7%). ESBL-producing was isolated from 38.2% of subclinical mastitic milk compared to 39.3% in clinical cases, where O26:k60, O125:k70, and O25:k11 were the serotypes with complete resistance to antibiotics. ESBL-producing isolates were resistant to cefotaxime, amoxicillin, cloxacillin, oxacillin, rifampicin, and penicillin in 100% but susceptible to amoxicillin and clavulanic acid in 82.5% of the cases. Results also revealed that 51.25%, 52.5%, 66.25%, 77.5% and 60% of ESBL-producing isolates were responsive to ciprofloxacin, ofloxacin, norfloxacin, levofloxacin, and gentamycin, respectively. The detected genes were registered in GenBank as MW345819.1 and MW345820.1 for the gene and MW295407 for the gene.

CONCLUSION

This study found ESBL-producing in mastitic milk samples from Egyptian dairy farms and confirmed the occurrence and circulation of the main antibiotic genes ( and ) in the samples. Regular and thorough surveillance of ESBL-producing and subsequent preventive actions are essential for preventing the spread of these resistance genes in the future, which could pose serious and catastrophic health risks. Authorities should cling to the concept of One Health to minimize the risk of new varieties.