TY - JOUR
T1 - Effects of feeding pasteurized waste milk to dairy calves on phenotypes and genotypes of antimicrobial resistance in fecal Escherichia coli isolates before and after weaning
AU - Maynou, G.
AU - Migura-Garcia, L.
AU - Chester-Jones, H.
AU - Ziegler, D.
AU - Bach, A.
AU - Terré, M.
N1 - Publisher Copyright:
© 2017 American Dairy Science Association
PY - 2017/10
Y1 - 2017/10
N2 - The aim of this study was to evaluate the effects of feeding pasteurized waste milk (pWM) to calves on antimicrobial resistance of fecal Escherichia coli at both phenotypic and genotypic levels. Fifty-two Holstein female calves (3 ± 1.3 d of age) were fed 1 of the 2 different types of milk: milk replacer (MR) without antimicrobials or pWM with β-lactam residues until weaning at 49 d of age. Fecal swabs of all calves were obtained on d 0, 35, and 56 of the study and 3 E. coli isolates per sample were studied. Phenotypic resistance was tested by the disk diffusion method against a panel of 12 antimicrobials. A total of 13 resistance genes consisting of β-lactam, sulfonamide, tetracycline, and aminoglycoside families were examined by PCR. Feeding pWM to calves increased the presence of phenotypic resistance to ampicillin, cephalotin, ceftiofur, and florfenicol in fecal E. coli compared with MR-fed calves. However, the presence of resistance to sulfonamides, tetracyclines, and aminoglycosides was common in dairy calves independent of their milk-feeding source, suggesting other factors apart from the feeding source are involved in the emergence of antimicrobial resistance.
AB - The aim of this study was to evaluate the effects of feeding pasteurized waste milk (pWM) to calves on antimicrobial resistance of fecal Escherichia coli at both phenotypic and genotypic levels. Fifty-two Holstein female calves (3 ± 1.3 d of age) were fed 1 of the 2 different types of milk: milk replacer (MR) without antimicrobials or pWM with β-lactam residues until weaning at 49 d of age. Fecal swabs of all calves were obtained on d 0, 35, and 56 of the study and 3 E. coli isolates per sample were studied. Phenotypic resistance was tested by the disk diffusion method against a panel of 12 antimicrobials. A total of 13 resistance genes consisting of β-lactam, sulfonamide, tetracycline, and aminoglycoside families were examined by PCR. Feeding pWM to calves increased the presence of phenotypic resistance to ampicillin, cephalotin, ceftiofur, and florfenicol in fecal E. coli compared with MR-fed calves. However, the presence of resistance to sulfonamides, tetracyclines, and aminoglycosides was common in dairy calves independent of their milk-feeding source, suggesting other factors apart from the feeding source are involved in the emergence of antimicrobial resistance.
KW - antimicrobial resistance
KW - calf
KW - pasteurized waste milk
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U2 - 10.3168/jds.2017-13040
DO - 10.3168/jds.2017-13040
M3 - Article
C2 - 28755935
AN - SCOPUS:85025838167
SN - 0022-0302
VL - 100
SP - 7967
EP - 7979
JO - Journal of Dairy Science
JF - Journal of Dairy Science
IS - 10
ER -