Veterinary pharmaceuticals and antibiotic resistance of Escherichia coli isolates in poultry litter from commercial farms and controlled feeding trials

Abstract

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 fertilizer, 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 Escherichia 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 analyzed 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. This 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 multiresistant to at least 7 antibiotics. Resistance to beta-lactam antibiotics (amoxicillin, ceftiofur), tetracyclines, and sulfonamides was the most prevalent. This study concluded that broiler litter is a source of antimicrobial residues and represents a reservoir of multiple antibiotic-resistant E. coli.

Scientific Opinion on the public health risks of bacterial strains producing extended-spectrum β-lactamases and/or AmpC β-lactamases in food and food-producing animals

“…The role of antibiotic selection pressure is also important, from agents used in both animal husbandry and human medicine (Blazquez et al, 2000;Jorgensen et al, 2007;Medeiros, 1997;Rice et al, 1996) in the selection of resistance in commensal bacteria in the gut of food animals (van den Bogaard et al, 2001). Resistance can also emerge in bacteria in soil as a result of pressure from antibiotic residues resulting from the use of antimicrobials in animal husbandry; such residues have been found in all components of the ecosystem, including the farm environment (Sayah et al, 2005), with recent reports of ESBLproducing E. coli found along with antibiotic residues in animal manure (Furtula et al, 2010).…”

Antibiotic resistance and resistance genes in Escherichia coli from poultry farms, southwest Nigeria

“…This may result in a selective advantage and a consequent increase in the abundance of resistant bacteria in animals, their wastes and surrounding environment [5]. Antibiotic resistant bacteria have been detected in poultry waste [7,8,6,9], commercial poultry production environments [10,11] and poultry products [12,13].…”

Broiler Farmers’ Behavior in Administering Antibiotic and Types of Antibiotic Content in Commercial Feed (A Case Study)

“…Mason (2010) reported more than 70% of antibiotic product in America was administered for cattle feed. Furtula et al (2010) .The nonrecommended antibiotic for feed caused great concern regarding the long term administration and the long post-expiry date (Oxytetracyclin, 28 days). This indicated violation on AGP administration by feed producers and the weak government control over cattle feed in commerce.…”