Molecular and phenotypic characterization of avian pathogenic Escherichia coli isolated from commercial broilers and native chickens

Thotsapol Thomrongsuwannakij; Ruethai Narinthorn; Tanakamol Mahawan; Patrick J Blackall

doi:10.1016/j.psj.2021.101527

Molecular and phenotypic characterization of avian pathogenic Escherichia coli isolated from commercial broilers and native chickens

Poult Sci. 2022 Jan;101(1):101527. doi: 10.1016/j.psj.2021.101527. Epub 2021 Oct 14.

Authors

Thotsapol Thomrongsuwannakij¹, Ruethai Narinthorn², Tanakamol Mahawan², Patrick J Blackall³

Affiliations

¹ Akkhraratchakumari Veterinary College, Walailak University, Nakorn Si Thammarat 80160, Thailand; One Health Research Center, Walailak University, Nakhon Si Thammarat 80160, Thailand. Electronic address: thotsapol.th@wu.ac.th.
² Akkhraratchakumari Veterinary College, Walailak University, Nakorn Si Thammarat 80160, Thailand; One Health Research Center, Walailak University, Nakhon Si Thammarat 80160, Thailand.
³ Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St Lucia 4067, Australia.

Abstract

Many studies have examined avian pathogenic Escherichia coli (APEC) from commercial broilers but few have examined isolates from native chickens. This study compared APEC isolates from commercial broilers and native chickens in regard to the phylogenetic group and the phenotypic and genotypic antimicrobial resistance profiles. From 100 suspect colibacillosis cases in both commercial broilers and native chickens, a total of 90 broiler isolates and 42 native chicken isolates were identified as E. coli by biochemical tests. Phylogenetic grouping revealed that 90 broiler APEC isolates belonged to A group (5.56%), B1 group (22.22%), B2 group (31.11%), and D group (41.11%). The 42 native chicken APEC isolates belonged to A group (35.71%), B1 group (26.19%), B2 group (30.95%), and D group (7.14%). The difference in the allocation to groups A and D of the 2 isolate types was significant (P < 0.05). The APEC broiler isolates had a significantly higher multidrug-resistant (MDR) rate (80%) than the native chicken isolates (14.29%) (P < 0.05). The APEC broiler isolates demonstrated significantly higher resistance rates than the native chicken isolates for amoxicillin (98.89%; 78.57% respectively), chloramphenicol (42.2%; 9.5%), enrofloxacin (68.9%; 7.1%), gentamicin (11.1%; 0%), nalidixic acid (72.2%; 7.1%), sulfamethoxazole + trimethoprim (45.6%; 2.4%), and tetracycline (88.9%; 76.2%) (P < 0.05). The APEC broiler isolates had a significantly higher presence compared with the native chicken isolates of the following resistance genes:- by bla_TEM (43.3%; 21.4%, respectively), cml-A (34.4%; 2.4%), tetA (76.7%; 40.5%), tetB (26.7%; 0%), sul2 (23.3%; 14.3%), and dhfrI (13.3%; 0%) (P < 0.05). The qnrB and qnrS genes were detected (12.16%; 72.97% respectively), in the APEC broiler isolates resistant to nalidixic acid and/or enrofloxacin while only qnrS genes was detected in all 3 APEC native chicken isolates. Regarding the point mutations of gyrA and parC, all isolates were positive to gyrA83S, gyrA87D, gyrA87L, gyrA87NY, parC80S and parC80I except that gyrA83S was not present in 20 APEC broiler isolates. Antimicrobial stewardship programs should be targeted at the backyard poultry sector as well as the commercial poultry sector.

Keywords: antimicrobial resistance; avian pathogenic Escherichia coli; commercial broiler; native chicken; resistance gene.

MeSH terms

Animals
Chickens*
Escherichia coli* / genetics
Phylogeny