Investigation of beta lactam resistance in Escherichia coli isolated from wild bird feces.

Abstract The study's objective was to identify beta-lactamase-resistant Escherichia coli both phenotypically and genotypically in the feces of resident wild birds and passing migrants in the Marmara region. The study involved 272 noninvasively collected fresh fecal samples. The birds of interest were categorized into four groups, assuring that each group comprised 68 samples as follows: Group 1 = resident wild waterbirds; Group 2 = urban resident terrestrial birds; Group 3 = winter migrants; and Group 4 = summer migrants. Extended-spectrum beta-lactamase (ESBL) and ampicillin Class C (AmpC) beta-lactamase positivity of E. coli isolates grown on cefotaxime-supplemented MacConkey agar were assessed by phenotypic screening and confirmation tests in sixty-two (62/272; 22.8%) out of 84 E. coli strains, irrespective of group-wise distribution. Fifty of these E. coli strains were positive for ESBL, 7 for AmpC, and 5 showed both ESBL and AmpC activities. E. coli isolates were detected in fifty-nine (21.7%) of 272 birds, and 57 of these 59 birds were positive for ESBL, six for AmpC, and six for both ESBL and AmpC. Modified Hodge Test revealed no carbapenemase production. Forty-eight out of 84 E. coli isolates grown on cefotaxime-supplemented MacConkey agar were positive for ESBL, three for AmpC, and 5 for both ESBL and AmpC-encoding genes by Polymerase Chain Reaction. The distribution of genes was blaCTX−M (n = 50), blaSHV (n = 2), and blaOXA10 (n = 10) for ESBL and blaMOX (n = 6) and blaCIT (n = 2) for AmpC. Carbapenemase genes (blaKPC, blaVIM, blaOXA, blaNDM−1) were undetected. According to the group and species-wise findings, Group 1, predominantly in seagulls, harbored the highest rates of ESBL- and/or AmpC-producing E. coli isolates. Considering that the seagull species that feed on human, animal, and agricultural waste products mainly through garbage dumps are widely distributed in Istanbul, the antimicrobial resistance in E. coli strains collected from wild birds is considered to be of human and/or animal origin.