A New Resistance Gene, linB , Conferring Resistance to Lincosamides by Nucleotidylation in Enterococcus faecium HM1025

Abstract

ABSTRACT Resistance to lincomycin and clindamycin in the clinical isolate Enterococcus faecium HM1025 is due to a ribosomal methylase encoded by an ermAM -like gene and the plasmid-mediated inactivation of these antibiotics. We have cloned and determined the nucleotide sequence of the gene responsible for the inactivation of lincosamides, linB . This gene encodes a 267-amino-acid lincosamide nucleotidyltransferase. The enzyme catalyzes 3-(5′-adenylation) (the adenylation of the hydroxyl group in position 3 of the molecules) of lincomycin and clindamycin. Expression of linB was observed in both Escherichia coli and Staphylococcus aureus . The deduced amino acid sequence of the enzyme did not display any significant homology with staphylococcal nucleotidyltransferases encoded by linA and linA ′ genes. Sequences homologous to linB were found in 14 other clinical isolates of E. faecium , indicating the spread of the resistance trait in this species.