Antimicrobial resistance profile and detection of β-lactamase genes in Klebsiella pneumoniae isolated from sheep in Tuban, Indonesia

Abstract

An opportunistic Gram-negative bacterium of veterinary and public health significance, Klebsiella pneumoniae is increasingly linked to the synthesis of extended-spectrum β-lactamase (ESBL) and multidrug resistance (MDR). The purpose of this study was to ascertain the distribution of β-lactamase genes (blaCTX-M, blaSHV, and blaTEM), antibiotic susceptibility profile, and prevalence of K. pneumoniae isolated from sheep in Tuban Regency, Indonesia. Sheep in Ngrayung Village, Plumpang District, provided 150 rectal swab samples. These samples were cultured on MacConkey Agar, followed by Gram staining, biochemical identification (TSIA and IMViC), and antimicrobial susceptibility testing using the Kirby-Bauer disk diffusion method. PCR was subsequently performed on selected resistant isolates to detect ESBL-associated genes (blaCTX-M, blaSHV, and blaTEM). K. pneumoniae was identified in 17 isolates (11.3%) out of the 150 samples. Testing for antimicrobial susceptibility showed 100% resistance to erythromycin and 88.2% resistance to ampicillin, but 100% susceptibility to aztreonam. No isolate fulfilled the international consensus definition of multidrug resistance (MDR) after exclusion of intrinsic resistance traits. Only one of the two selected resistant isolates (50%) carried the blaSHV gene, according to PCR analysis, while no isolates had blaCTX-M or blaTEM. The detection of antimicrobial-resistant K. pneumoniae in sheep that appear to be in good condition suggests that animals could act as reservoirs for bacteria resistant to antibiotics. The limited detection of ESBL-associated genes suggests that additional resistance mechanisms may contribute to the observed phenotypic resistance. In order to reduce the spread of resistant bacteria, these results emphasize the necessity of ongoing surveillance and careful antibiotic usage in animal production under the One Health framework.