Anotace:
The aim of the present study was to monitor the presence of extended-spectrum beta-lactamase (ESBL) producing E. coli on farm A with the history of previous use of ceftiofur in suckling pigletsand to analyse the risk factors of selection and dissemination of ESBL producers in the production herd. In the year of 2014, a total of 411 samples (rectal swabs or faeces)from pigs of various age categories (sows, gilts and suckling piglets) were collected. The sampling was performed more than 24 months after the ban of ceftiofur on the farm.The sows and gilts were sampled repeatedly before and after farrowing. All collected samples were directly cultivated on MacConkey agar (MCA) containing cefotaxime (2 mg/l) and obtained sub-cultures were tested for ESBL production by double disc synergy test. According to our results, all gilts were negative for ESBL-producing E. coli in the introduction period, however, the excretion of ESBL-producing E. coli was observed before and after delivery. Most of the new-born piglets from positive sows and gilts shed ESBL-producing E. coli early after birth. All tested ESBL-producing isolates were resistant to multiple antimicrobials, suggesting that antibiotics from other groups used for therapy co-select for ESBL producers in pigs on the studied farm. Intestinal colonization of lactating sows and their offspring as well as survival of ESBL-producing E. coli in the farm environment should be recognised as important risk factors of circulation and long-time persistence of ESBL producers in the herd.