Effect of preweaned dairy calf housing system on antimicrobial resistance in commensal Escherichia coli

Abstract

Group housing of preweaned dairy calves is a growing practice in the United States. The objective of this practice is to increase the average daily gain of calves in a healthy and humane environment while reducing labor requirements. However, feeding protocols, commingling of calves, and occurrence of disease in different calf-housing systems may affect the prevalence of antimicrobial drug-resistant bacteria. This study evaluated the effect of a group pen-housing system and individual pen-housing system on antimicrobial resistance trends in fecal Escherichia coli of preweaned dairy calves and on the prevalence of environmental Salmonella. Twelve farms from central New York participated in the study: 6 farms using an individual pen-housing system (IP), and 6 farms using a group pen-housing system (GP). A maximum of 3 fecal E. coli isolates per calf was tested for susceptibility to 12 antimicrobial drugs using a Kirby-Bauer disk diffusion assay. Calves in GP had a significantly higher proportion of E. coli resistant to ciprofloxacin and nalidixic acid, whereas calves in IP had a significantly higher proportion of E. coli resistant to ampicillin, ceftiofur, gentamycin, streptomycin, and tetracycline. Calf-housing system had an effect on resistance to individual antimicrobial drugs in E. coli, but no clear-cut advantage to either system was noted with regard to overall resistance frequency. No outstanding difference in the richness and diversity of resistant phenotypes was observed between the 2 calf-housing systems.

Resistencia a antimicrobianos en E. coli y Salmonella spp. de terneros del sur de Chile

“…We found only 10% of E. coli, 19% of β-hemolytic E. coli and 29% of Salmonella spp. isolates sensitive to all antimicrobials tested, results similar results to those previously reported, where 11.7-18.2 to 39% of E. coli isolates were all sensitive E. coli (24,25). Isolates in our study originated from sick calves, some of which had been subject of unsuccessful antimicrobial treatments.…”

“…Estos hallazgos son similares extensive resistance. These results are similar to what was found in central New York, where ampicillin was also found as a prevalent AMR phenotype among other resistances (25). Ceftiofur should be the recommended treatment for E. coli diarrheas, while gentamicin appears to be the recommended antimicrobial for Salmonella spp.…”

“…(24,25). Los aislamientos en nuestro estudio se originaron a partir de terneros enfermos, algunos de los cuales habían sido sujetos a tratamientos antimicrobianos fallidos.…”

“…Estos resultados concuerdan con un estudio que no observó ningún efecto de la edad sobre la resistencia a los that observed no effect of age on antimicrobial resistance in calves, while evaluating the effect on housing type and resistance (25). In contrast, other studies reported an effect of age in AMR (14,26).…”

“…Also, in cases of suspected Salmonella spp. outbreaks in calves, amoxicillin and oxytetracycline should be avoided due to antimicrobianos en terneros, al tiempo que evaluó el efecto sobre el tipo de vivienda y resistencia (25). En contraste, otros estudios informaron un efecto de la edad en la RAM (14,26).…”