ASSESSMENT OF ANTIMICROBIAL RESISTANCE IN Escherichia coli AND SALMONELLA ISOLATED FROM INTEGRATED BROILER CHICKEN FARMS
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Date
2022
Journal Title
Journal ISSN
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Publisher
KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR
Abstract
A study was conducted to identify the driving factor of AMR by monitoring the
phenotypic and genotypic AMR of E. coli and Salmonella isolated from 3 broiler farms (2
integrated and 1 associated). In all, 101 samples were collected at different sampling points
in one entire crop cycle. The overall presence of E. coli and Salmonella was 76.23 and 9.09
per cent. Farm 1 samples did not yield Salmonella. Antimicrobial resistance based on disc
diffusion assay and MIC revealed that all E. coli and Salmonella isolates were resistant to
at least one antibiotic. E. coli and Salmonella showed highest resistance to ampicillin and
doxycycline (92 and 87%), followed by enrofloxacin, gentamicin, trimethoprim
sulphamethoxazole, amikacin and colistin and lesser resistance to ceftiofur. All the isolates
were further screened for the presence of 22 AMR genes belonging to three groups of
antibiotics by PCR. Among the AMR genes, highest presence was recorded for
qnrB(96.87%), qepA(92.7%) followed by blaTEM(71.96%), blaCTX-M universal(29.56%),
qnrS (28.93%), qnrD (28.62%), blaCTX-Mgroup1 (10.8%), mcr3 (6.27%), blaCTX-M group2
(5.64%), oqxAB (5.5%), blaSHV (4%), blaOXA (2.5%), blaCTX-M group 8/25 (1.85%),
aac(6’)-Ib-cr (1.5%) and qnrA (0.5%) in E. coli. In Salmonella, blaTEM and blaSHV (100%)
followed by qnrD (68.3%), qnrB (61.6%), qnrA (15%) and oqxAB (5%) in Salmonella.
Maximum AMR genes in E. coli and Salmonella were found in boot socks, ileal and cecal
contents and fecal swabs. Thus, these may be the driving factors for AMR. Also, on day
zero high prevalance of AMR genes was found. A significant correlation was observed
between phenotypic and genotypic AMR of β Lactams and quinolones but not for colistin.
No significant difference was observed in the overall AMR pattern between integrated and
associated farms. The findings calls for the need of efficient monitoring and institution of
control strategies for effective mitigation of AMR in all the three broiler farms.