Prevalence and molecular characterization of extended-spectrum β-lactamase (ESBL) and plasmidic AmpC β-lactamase (pAmpC) producing Escherichia coli in dogs

This study aimed to determine the prevalence of fecal carriage of extended spectrum β-lactamase (ESBL) and/or plasmidic AmpC β-lactamase (pAmpC) producing Escherichia coli among dogs (n=428) in Turkey. Polymerase chain reaction (PCR) and sequencing were used to characterize genes encoding β-lactamase and plasmid mediated quinolone resistance (PMQR). Antimicrobial susceptibility testing and PCRs for virulence genes and phylogenetic groups were also performed. Cefotaxime resistant E. coli isolates were detected in 95 (22.2%) of the swab samples. Sequencing analysis results showed occurrence of various β-lactamase genes: blaCTX-M-15 (62), blaTEM-1b (42), blaCMY-2 (22), blaCTX-M-3 (16), blaCTX-M-1 (15), blaOXA-1 (9) and blaSHV-12 (3) alone or in combination. The most frequently encountered phylogenetic group was group A1 (35.8%), followed by group D2 (22.1%), B1 (15.8%), D1 (9.5%), A0 (7.4%), B22 (5.3%) and B23 (4.2%), respectively. PMQR genes, aac(6')-Ib-cr, qnrS1 and qnrB10 were detected in 25.3, 10.5 and 1.1% of the isolates, respectively. While all isolates were susceptible to imipenem and amikacin, resistance rates to non-β-lactam antibiotics ranged from 20.0% for tobramycin to 56.8% for tetracycline. The virulence genes were only detected in 34 (36.2%) of the isolates and this isolates carried single or various combination of virulence genes of iucD, papC, papE, f17a-A and eaeA. Four isolates were identified as human virulent pandemic CTX-M-15 producing E. coli clone O25b:ST131/B2. To the best of our knowledge, this is the first study to show fecal carriage of ESBL/pAmpC type β-lactamase producing E. coli isolates among dogs in Turkey.