Nucleotide sequence of the fosB gene conferring fosfomycin resistance in Staphylococcus epidermidis.

We have determined the nucleotide sequence of gene fosB of plasmid pIP1842, which confers resistant to fosfomycin in Staphylococcus epidermidis BM2641. The resistance gene was identified as a coding sequence of 417 bases pairs corresponding to a protein with a calculated Mw of 16,345 daltons. This value is in good agreement with that of 15,000, estimated by SDS-polyacrylamide gel electrophoresis of a bacterial cell-free coupled transcription-translation system. The fosB gene product exhibits 48% sequence homology with the fosfomycin resistance protein FOSA of Enterobacteriaceae. The substitutions are scattered throughout indicating that the two corresponding genes have diverged from a common ancestor. Downstream from fosB is located an open reading frame that was partially sequenced. The deduced amino-acid sequence was 50% homologous to REP alpha 1, a protein involved in the replication of the Enterococcus faecalis plasmid pAM alpha 1.