Characterisation of ceftiofur resistance in swine bacterial pathogens.

A PCR based method was developed for the identification of ceftiofur resistance genes (bla(CMY-2), bla(TEM-1), and ampC) in swine bacterial pathogens. Using this method, the ceftiofur resistant (n=76) and susceptible (n=45) strains of Bordetella bronchiseptica, Salmonella spp., Escherichia coli, and Pasteurella multocida were screened for the presence of these three genes. The resistant genes were detected in 70% (bla(TEM-1)), 68% (bla(CMY-2)) and 45% (ampC) of the resistant isolates and in 18% (bla(TEM-1)), 27% (bla(CMY-2)), and 36% (ampC) of the susceptible isolates. Results obtained in the present study showed widespread distribution of these three resistance genes in ceftiofur-resistant swine pathogens. It was also observed that more pathogens are acquiring these resistance genes. 2009 Elsevier Ltd. All rights reserved.