title: Inter-batch contamination and potential sources of vancomycin-resistant  Enterococcus faecium  on broiler farms.
abstract: 1. Vancomycin-resistant Enterococcus faecium (VRE(fm)) has recently spread among Swedish broiler farms. The objectives were to investigate VRE(fm) persistence within barns between flocks, and to determine whether day-old chicks, feed or forklift trucks used for loading crates could be identified as a means of transmission.   2. Faeces were collected for selective culture from 12 farms (9 culture-positive, 3 culture-negative as determined by prior monitoring), and samples were collected from the barn environment before and after cleaning and disinfection, from forklift tyres, hatcheries and feed.   3. VRE(fm) was isolated only from previously known VRE(fm)-positive farms. The proportions of culture-positive environmental samples were 75% (9 out of 9 farms) prior to and 31% (7 out of 9 farms) after cleaning/disinfection. Five out of 6 samples from forklift tyres were culture-positive. No VRE(fm) were isolated from feed or hatcheries. The majority of 27 vanA gene positive isolates showed similar banding patterns by SmaI restriction digestion and pulse-field gel electrophoresis. No consistent differences were observed regarding management between VRE(fm)-positive and negative farms.   4. We conclude that VRE(fm) contaminates barns and remains present between flocks. Forklift trucks are one possible means of transmission between farms.
authors: National Veterinary Institute-SVA, Department of Animal Health and Antimicrobial Strategies, SE751 89 Uppsala, Sweden. desiree.jansson@sva.se
authors: D S
authors: DS
authors: Jansson
authors: O
authors: O
authors: Nilsson
authors: J
authors: J
authors: Lindblad
authors: C
authors: C
authors: Greko
authors: B
authors: B
authors: Bengtsson
mesh_terms: D000821:Animal Feed / Q000382:microbiology; D000822:Animal Husbandry; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D019729:Carbon-Oxygen Ligases / Q000235:genetics; D002645:Chickens; D015169:Colony Count, Microbial / Q000662:veterinary; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D016521:Electrophoresis, Gel, Pulsed-Field / Q000662:veterinary; D016984:Enterococcus faecium / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D011201:Poultry Diseases / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission*; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D013548:Sweden / Q000453:epidemiology; D014186:Transportation; D020713:Vancomycin Resistance
chemical_list: D001426:Bacterial Proteins; C071437:VanA ligase, Bacteria; C025651:CCCGGG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific; D019729:Carbon-Oxygen Ligases