Isolation and antimicrobial resistance pattern of Escherichia coli O157:H7 from layer poultry farms in Bishoftu town, Ethiopia
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Date
2022
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Addis Abeba University
Abstract
Escherichia coli O157: H7 (E. coli O157:H7) is a zoonotic pathogen responsible for the majority of severe cases of human enterohemorrhagic E. coli disease. However, the precise attribution of chickens and their food products as the sources of this zoonotic serotype has not yet been thoroughly investigated in Bishoftu town. Therefore, a cross-sectional study was conducted from November 2021 to May 2022 on different sizes of layer poultry farms found in Bishoftu town to isolate, characterize, and determine the antimicrobial resistance profile of E. coli O157: H7. For this study, a total of 420 samples were collected from cloacae, eggs shells, the contents of eggs, personnel hands and the chicken environments. E. coli O157: H7 was isolated and confirmed using bacteriological, biochemical, and the latex-agglutination methods. All of the isolates were subjected to molecular characterization and susceptibility testing against twelve selected antimicrobials. Farm level information on the potential risk factors was collected using semistructured questionnaires. Of a total of 420 samples examined, E. coli was detected in 66 (15.71 %; 95 % CI: 12.37, 19.55) whereas E. coli O157:H7 was confirmed in 16 (3.81%; 95 % CI: 2.19, 6.11) of the samples using the latex method. Of the 16 isolates, 9 (56.25 %) were from cloacae samples, 3 (18.75 %) were from litter samples, 1 (6.25 %) was from personnel hands, and 3 (18.75 %) were from egg shell swabs. The study showed that there was a statistically significant difference in the prevalence of E. coli O157: H7 among the different farm sizes and between chicken age groups. The odds of isolation of E. coli O157: H7 were 5.5 times greater in smallscale
farms than in large-scale poultry farms and 4.1 times higher in adult chickens than in their younger counterparts. PCR amplification of intimin (eae) and shiga toxin (stx1) genes specific for E. coli O157: H7 using specific primers identified eae gene from 7 (43.75%) E. coli O157:H7 isolates, but stx1 was not detected. The results of antimicrobial sensitivity showed that 75% and 62.50% of the isolates had developed resistance against ampicillin and amoxacillin, respectively.
On the other hand, 87.50% of the isolates were susceptible to gentamycin. Resistance to three or more drugs was detected in 68.7% of the isolates, which signifies a public health risk. The results of this study revealed the circulation of E. coli O157:H7 in poultry, their products and environ. Therefore, further research is highly encouraged to investigate the distribution of E. coli O157: H7 at human poultry interface and the driving factors of antimicrobial resistance in this setting.
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Keywords
Antimicrobials,Isolation, Poultry,, Bishoftu, Characterization, E. coli O157:H7