Longitudinal study on the prevalence of extended spectrum cephalosporins-resistant Escherichia coli colonization in Dutch veal farms.

ABSTRACT

A longitudinal study was performed to investigate the prevalence of Extended-Spectrum Cephalosporin-Resistant (ESC-R) Escherichia coli colonization in Dutch veal farms. Rectal swabs from 683 calves born in 13 Dutch dairy farms were collected one day prior to transportation to the veal farm at 14 or 28 days of age, and at 5 different time points 8 Dutch veal farms. In addition, characteristics of the calf, cows, and farm management were collected. Rectal swabs were selectively cultured for ESC-R E. coli. In total, 1202 ESC-R E. coli isolates were recovered. Overall, the prevalence of ESC-R E. coli increased from 24.4 % at one day prior to transportation to 57.3 % in week two after arrival of calves at the veal farm. No associations were found between the presence of ESC-R E. coli at the dairy or veal farm and age of transportation, sex and breed. The presence of ESC-R E. coli in week 6, 10, and 18 at the veal farm was positively associated with the presence of ESC-R E. coli in week 10, 18, and 24, respectively (p < 0.05). Individual antibiotic treatments applied before week 2 and 6 upon arrival to the veal farms tended to increase the ESC-R E. coli colonization frequency. Our results indicate that ESC-R E. coli colonization frequency substantially increases after arrival of calves on the veal farm. In addition to individual antibiotic treatments, it is considered likely that frequently applied batch antibiotic treatments are also implicated in the ESC-R E. coli colonization frequency.