Genotyping of extended-spectrum beta-lactamase-producing Escherichia coli isolated from wastewater of dairy farms in East Java, Indonesia

Abstract

Background and Aim: Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in dairy farm wastewater represents a significant threat to environmental and public health due to the dissemination of antibiotic-resistance genes. This study investigates the molecular profiles of ESBL-producing E. coli isolates harboring blaCTX-M, blaTEM, and blaSHV genes from dairy farm wastewater in East Java, Indonesia. Materials and Methods: Wastewater samples (n = 342) were collected from six major dairy regions in East Java: Pasuruan, Malang, Tulungagung, Blitar, Batu, and Kediri. The samples underwent bacterial isolation, identification, and ESBL phenotypic screening using the double-disk synergy test (DDST). Molecular genotyping of blaCTX-M, blaTEM, and blaSHV was conducted using a polymerase chain reaction. Results: Of the samples, 69.30% (237/342) tested positive for E. coli, with 32.91% (78/237) identified as ESBL producers through DDST. Molecular genotyping confirmed ESBL genes in 28.20% (22/78) of the isolates. The genotypic distribution was 77.2% (17/22) blaTEM, 4.5% (1/22) blaCTX-M, 9.0% (2/22) blaTEM + blaSHV, and 9.0% (2/22) blaTEM + blaCTX-M. These findings highlight the dominance of blaTEM and the presence of multi-gene combinations in East Java’s dairy farm wastewater. Conclusion: The identified molecular profiles underscore dairy farm wastewater as a critical reservoir for antibiotic resistance genes, particularly blaTEM. Addressing this issue necessitates stringent antimicrobial use policies, improved wastewater management, and enhanced biosecurity measures. These findings support a One Health approach to mitigate environmental and public health risks associated with AMR. Keywords: antibiotic resistance, blaCTX-M, blaSHV, blaTEM, dairy farm wastewater, ESBL-producing Escherichia coli, Indonesia, public health.