Antimicrobial Resistance of Escherichia fergusonii Isolated from Broiler Chickens.
The objective of this study was to investigate the antibiotic resistance of Escherichia fergusonii isolated from commercial broiler chicken farms. A total of 245 isolates from cloacal and cecal samples of 28- to 36-day-old chickens were collected from 32 farms. Isolates were identified using PCR, and their susceptibility to 16 antibiotics was determined by disk diffusion assay. All isolates were susceptible to meropenem, amikacin, and ciprofloxacin. The most common resistances were against ampicillin (75.1%), streptomycin (62.9%), and tetracycline (57.1%). Of the 184 ampicillin-resistant isolates, 127 were investigated using a DNA microarray carrying 75 probes for antibiotic resistance genetic determinants. Of these 127 isolates, the β-lactamase blaCMY2, blaTEM, blaACT, blaSHV, and blaCTX-M-15 genes were detected in 120 (94.5%), 31 (24.4%), 8 (6.3%), 6 (4.7%), and 4 (3.2%) isolates, respectively. Other detected genes included those conferring resistance to aminoglycosides (aadA1, strA, strB), trimethoprims (dfrV, dfrA1), tetracyclines (tetA, tetB, tetC, tetE), and sulfonamides (sul1, sul2). Class 1 integron was found in 35 (27.6%) of the ampicillin-resistant isolates. However, our data showed that the tested E. fergusonii did not carry any carbapenemase blaOXA genes. Pulsed-field gel electrophoresis revealed that the selected ampicillin-resistant E. fergusonii isolates were genetically diverse. The present study indicates that the monitoring of antimicrobial-resistant bacteria should include enteric bacteria such as E. fergusonii, which could be a reservoir of antibiotic resistance genes. The detection of isolates harboring extended-spectrum β-lactamase genes, particularly blaCTX-M-15, in this work suggests that further investigations on the occurrence of such genes in broilers are warranted.
Agassiz Research and Development Centre, Agriculture and Agri-Food Canada (AAFC), Agassiz, British Columbia, Canada V0M 1A0.
Karen
K
Simmons
Guelph Research and Development Centre, AAFC, Guelph, Ontario, Canada N1G 5C9.
M Rashedul
MR
Islam
Agassiz Research and Development Centre, Agriculture and Agri-Food Canada (AAFC), Agassiz, British Columbia, Canada V0M 1A0.
Heidi
H
Rempel
Agassiz Research and Development Centre, Agriculture and Agri-Food Canada (AAFC), Agassiz, British Columbia, Canada V0M 1A0.
Glenn
G
Block
London Research and Development Centre, AAFC, London, Ontario, Canada N5V 4T3.
Edward
E
Topp
Guelph Research and Development Centre, AAFC, Guelph, Ontario, Canada N1G 5C9. Moussa.Diarra@agr.gc.ca.
Moussa S
MS
Diarra
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D002645:Chickens / Q000382:microbiology*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000235:genetics
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D001618:beta-Lactamases; C063912:carbapenemase