Relations between the consumption of antimicrobial growth promoters and the occurrence of resistance among Enterococcus faecium isolated from broilers.
The present study investigates, at farm level, the effect of the time-span between sampling and the last time a particular antimicrobial growth promoter (AGP) was included in the feed on the probability of selecting an AGP-resistant Enterococcus faecium isolate from a broiler flock. The probability that a randomly selected E. faecium isolate was resistant to avilamycin, erythromycin or virginiamycin was 0.91, 0.92 and 0.84, respectively if the isolate originated from a broiler flock fed either avilamycin- or virginiamycin-supplemented feed. As the time-span between sampling and the last AGP consumption increased, the probability of isolating an E. faecium isolate resistant to a particular AGP decreased (probability <0.2 within 3-5 years after last exposure to AGPs). The decrease in probability over time showed little farm-to-farm variation. The number of times a particular AGP was given to previous flocks reared in the same house had no effect on the probability of isolating a resistant isolate.
Danish Zoonosis Centre, Danish Veterinary Institute, Bülowsvej 27, DK-1790 Copenhagen V, Denmark.
H D
HD
Emborg
J S
JS
Andersen
A M
AM
Seyfarth
H C
HC
Wegener
D000821:Animal Feed; D000822:Animal Husbandry; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects*; D002645:Chickens; D003718:Denmark / Q000453:epidemiology; D004334:Drug Administration Schedule; D024881:Drug Resistance, Bacterial; D016984:Enterococcus faecium / Q000302:isolation & purification; D004917:Erythromycin / Q000008:administration & dosage / Q000009:adverse effects*; D016908:Gram-Positive Bacterial Infections / Q000139:chemically induced* / Q000453:epidemiology / Q000382:microbiology* / Q000662:veterinary; D016014:Linear Models; D016015:Logistic Models; D008390:Markov Chains; D008826:Microbial Sensitivity Tests; D009010:Monte Carlo Method; D009844:Oligosaccharides / Q000008:administration & dosage / Q000009:adverse effects*; D011201:Poultry Diseases / Q000139:chemically induced* / Q000453:epidemiology / Q000382:microbiology*; D013997:Time Factors; D014640:Vancomycin / Q000008:administration & dosage / Q000009:adverse effects*; D014769:Virginiamycin / Q000008:administration & dosage / Q000009:adverse effects*
D000900:Anti-Bacterial Agents; D009844:Oligosaccharides; D014769:Virginiamycin; D004917:Erythromycin; D014640:Vancomycin; C006653:avilamycin