Diverse and emerging molecular mechanisms award polymyxins resistance to Enterobacteriaceae clinical isolates from a tertiary hospital of Recife, Brazil

•This study characterizes the genetic basis of polymyxins resistance mechanisms in clinical Enterobacteriaceae isolates;•Different mechanisms could be found among few polymyxin-resistance Enterobacteriaceae clinical isolates from Recife, Brazil;•It shows the spreading of the IncX4 plasmid with mcr-1 through different Enterobacteriaceae species: E. coli and K. pneumoniae;•mcr-5 was found in a E. coli ST632 carried by an earlier described plasmid that seems liable for its dissemination in Brazil;•crrB mutation was blamed for polymyxins resistance in C. freundii and warns to its emerging among Enterobacteriaceae species.