Macrolide resistance conferred by rRNA mutations in field isolates of Mannheimia haemolytica and Pasteurella multocida

Abstract

High-level macrolide resistance can arise from 23S rRNA mutations in P. multocida and M. haemolytica despite their multiple copies of rrn. Selective pressures from exposure to different macrolide or lincosamide drugs presumably resulted in consolidation of either the A2058G or the A2059G mutation.