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Influence of avilamycin administration and its subsequent withdrawal on emergence and disappearance of antimicrobial resistance in enterococci in the intestine of broiler chickens
Author(s) -
Katsunuma Y.,
Hanazumi M.,
Fujisaki H.,
Minato H.,
Hashimoto Y.,
Yonemochi C.
Publication year - 2007
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2006.03140.x
Subject(s) - broiler , antimicrobial , microbiology and biotechnology , antibiotic resistance , enterococcus , biology , antibiotics , food science
Aims: To investigate the influence of avilamycin (AVM) administration and its subsequent withdrawal on the emergence and disappearance of AVM‐resistant enterococci in the intestine of broiler chickens. Methods and Results: Five chicks each of C, L and H groups were given the basal diet, the basal diet supplemented with 5 g AVM/ton and the basal diet supplemented with 50 g AVM/ton, respectively. The AVM‐resistant Enterococcus faecalis population did not emerge during 30 days of the AVM administration period, whereas the AVM‐resistant Enterococcus faecium with a minimum inhibitory concentration of >512 μ g ml −1 in the faeces of chicks of the L and H groups emerged on 3 and 1 days after the AVM administration, respectively. Thereafter, the AVM‐resistant Ent. faecium population density in both L and H groups maintained high levels during the AVM administration period. Twenty days after the AVM withdrawal, the AVM‐resistant Ent. faecium population disappeared from the intestines of both four of five chicks of L group and three of five chicks of H group. The AVM‐resistant Ent. faecium population density in one chick from each of the groups, L and H, did not change before and after the AVM removal. Conclusions: The AVM‐resistant Ent. faecium emerged during the AVM administration, and disappeared from the intestine of most chicks after the AVM withdrawal. However, the AVM‐resistant Ent. faecium persisted in some chicks 20 days after AVM withdrawal. Significance and Impact of the Study: Our results suggest that introducing an AVM withdrawal period could minimize the risk of AVM‐resistant Ent. faecium becoming carcass contaminants, and that prudent antibiotic use alone is not sufficient to stem emergence of the AVM‐resistant Ent. faecium .