Molecular basis of macrolide, triamilide, and lincosamide resistance in Pasteurella multocida from bovine respiratory disease.

The mechanism of macrolide-triamilide resistance in Pasteurella multocida has been unknown. During whole-genome sequencing of a multiresistant bovine P. multocida isolate, three new resistance genes, the rRNA methylase gene erm(42), the macrolide transporter gene msr(E), and the macrolide phosphotransferase gene mph(E), were detected. The three genes were PCR amplified, cloned into suitable plasmid vectors, and shown to confer either macrolide-lincosamide resistance [erm(42)] or macrolide-triamilide resistance [msr(E)-mph(E)] in macrolide-susceptible Escherichia coli and P. multocida hosts.