Detection and characterization of extended-spectrum beta-lactamase genes (blaTEM and blaSHV) among beta-lactam-resistant fecal coliforms of dairy cattle from Chhattisgarh, India

Abstract

The aim of this study was to isolate the antimicrobial-resistant enterobacteria from cattle feces and to identify the extendedspectrum beta-lactamase (ESBL) and carbapenemase gene among them. A total of 70 cattle fecal swab samples were collected fromDurg, Chhattisgarh, India, and cultured in nutrient broth. Bacterial isolation recovered 120 gram-negative bacteria. Antimicrobialsusceptibility testing showed 90 (75%) coliform isolates (66 Escherichia coli, 20 Klebsiella sp., and two each of Enterobacter sp. andCitrobacter sp.) resistant to amoxicillin, amoxicillin-clavulanic acid, cefixime, ceftazidime, imipenem, or meropenem. Bacterial isolatesshowed the highest resistance rate for ceftazidime (61.6%), followed by cefixime and amoxicillin-clavulanic acid (60%). The ESBLphenotype, assessed by combination disk method, was shown by 36 (40%) of the resistant isolates. PCR amplification revealed 20%and 31.6% positivity of blaTEM and blaSHV genes, respectively. blaTEM and blaSHV coexpression was recorded among eight (12.1%) E. coliand two (10%) Klebsiella sp. isolates. Restriction endonuclease analysis indicated clonal blaTEM and clonal and nonclonal blaSHV genes.Nucleotide sequencing confirmed the blaTEM and blaSHV genotypes. None of the isolates showed amplification of the carbapenemasegene. Phenotypic and genetic detection and characterization of ESBLs among Enterobacteriaceae bacteria illustrate the importance ofplanning and execution of effective control programs for emerging antimicrobial-resistant pathogens.