ShapeShapeauthorShapechevroncrossShapeShapeShapeGrouphamburgerhomeGroupmagnifyShapeShapeShaperssShape

Drug-Resistant E. Coli Found in Poultry Litter

by 5m Editor
22 December 2009, at 6:35am

CANADA - Broiler litter is a source of antimicrobial residues and represents a reservoir of multiple antibiotic-resistant <em>E. coli</em>, according to Canadian researchers.

Canadian researchers investigated the veterinary pharmaceuticals and antibiotic resistance of Escherichia coli isolates in poultry litter from commercial farms and controlled feeding trials.

According to Vetsweb, veterinary pharmaceuticals are commonly used in poultry farming to prevent and treat microbial infections as well as to increase feed efficiency, but their use has created public and environmental health concerns. Poultry litter contains antimicrobial residues and resistant bacteria; when applied as fertiliser, the level and effects of these pharmaceuticals and antimicrobial-resistant bacteria in the environment are of concern.

The purpose of this study was to investigate poultry litter for veterinary pharmaceuticals and resistance patterns of E. coli. Litter samples were collected from controlled feeding trials and from commercial farms. Feed additives bacitracin, chlortetracycline, monensin, narasin, nicarbazin, penicillin, salinomycin and virginiamycin, which were present in the feed on commercial farms and added to the feed in the controlled trials, were extracted in methanol and analysed by liquid chromatography-mass spectrometry techniques. Sixty-nine E. coli were isolated and identified by API 20E. The susceptibility of the isolates to antibiotics was determined using Avian plates and the Sensititer automated system.

The study confirmed the presence of antimicrobial residues in broiler litter from controlled environments as well as commercial farms, ranging from 0.07 to 66 mg/L depending on the compound. Concentrations of individual residues were higher in litter from controlled feeding trials than those from commercial farms. All E. coli isolates from commercial farms were multi-resistant to at least seven antibiotics. Resistance to beta-lactam antibiotics (amoxicillin, ceftiofur), tetracyclines, and sulphonamides was the most prevalent.

According to the researchers, broiler litter is a source of antimicrobial residues and represents a reservoir of multiple antibiotic-resistant E. coli, reports Vetsweb, citing a paper published in Poultry Science.