Abstract

Background:
The alarming rise in infections caused by extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in animals and humans poses a serious threat due to its escalating antibiotic resistance. Unveiling this problematic bacteria’s prevalence and resistance patterns in animals is crucial for formulating effective control strategies and safeguarding public health.

Aim:
The purpose of this study was to analyze the expression of three main genes: blaCTX-M, blaSHV, and blaTEM, in ESBL-producing E. coli isolates from The Research Center for Veterinary Science and the National Research and Innovation Agency. Moreover, their resistance profiles against various antibiotics should be systematically evaluated.

Methods:
Ninety-seven E. coli isolates from the bacteriology laboratory of The Research Center for Veterinary Science were identified on MacConkey medium supplemented with cefotaxime. The isolates were verified for the existence of the blaCTX-M, blaSHV, and blaTEM genes using PCR. Antimicrobial susceptibility testing was conducted using antibiotic discs following the CLSI standards.

Results:
The prevalence of ESBL-producing E. coli in chicken ceca, eggs, and fish intestines was 16.5% (16/97). The specific genes detected were blaCTX-M gene at 93.75% (15/16), followed by the blaTEM gene, at 81.25% (13/16), and blaSHV at 25% (4/16). The antimicrobial sensitivity test results revealed that all ESBL-producing E. coli isolates had multidrug resistance 81.25% to 1–5 antibiotics and 18.75% to 6–7 antibiotics. The isolate exhibited 100% resistance to ampicillin and sulfamethoxazole, with exclusive sensitivity to chloramphenicol.

Conclusion:
The dominant gene in the ESBL-producing isolates was blaCTX-M. This bacterium is completely resistant to ampicillin and sulfamethoxazole, whereas it displays multidrug resistance to 1–7 different types of antibiotics.

Key words: Escherichia coli, ESBL, blaCTX-M, blaTEM, blaSHV