Abstract

An increase of multi-drug resistant Escherichia coli in swine husbandry have been concerned worldwide. This study aimed to determine the multidrug resistance and nucleotide substitution of beta-lactam antibiotic and tetracycline resistant genes in E. coli from swine farms in Southern Thailand. A total of 112 isolates of E. coli was isolated from 50 pig farms, which were confirmed by identified by MALDI-TOF analysis. Seventy-three isolates (65.18%) and 39 isolates (34.82%) were isolated from the feces and waste water samples, respectively. One hundred percent resistance to beta-lactam antibiotics as well as their resistant gene bla<inf>TEM</inf> was detected in isolates. Furthermore, 81% isolates were tetracycline resistance and both tetA [68.42% (13/19) in feces samples, 72.73% (8/11) in waste water samples] and tetB [10.53% (2/19) in feces samples, 18.18% (2/11) in waste water samples] genes responsible for tetracycline resistance were observed. Furthermore, 54 isolates had multi-drug resistance that presented 11 different patterns. The nucleotide substitution of genes was detected in 3 isolates of E. coli, and may consider as the point mutation. The nucleotide at 859 bp of tetA gene of the isolate WU-WW009-01 was changed from T to A. While, the isolate WU-WW004-02 showed 2 nucleotide substitution sites at the position of 266 (from A to G) and 859 (from T to G) bp. The nucleotide at 36 bp of bla<inf>TEM</inf> gene of the isolate WU-F003-02 was replaced from G to A. Findings of this study may help to control the spread of E. coli antibiotic resistance genes in the swine farms.