Stenotrophomonas maltophilia D457R Contains a Cluster of Genes from Gram-Positive Bacteria Involved in Antibiotic and Heavy Metal Resistance

Abstract

ABSTRACT A cluster of genes involved in antibiotic and heavy metal resistance has been characterized from a clinical isolate of the gram-negative bacterium Stenotrophomonas maltophilia . These genes include a macrolide phosphotransferase ( mphBM ) and a cadmium efflux determinant ( cadA ), together with the gene cadC coding for its transcriptional regulator. The cadC cadA region is flanked by a truncated IS 257 sequence and a region coding for a bin3 invertase. Despite their presence in a gram-negative bacterium, these genetic elements share a common gram-positive origin. The possible origin of these determinants as a remnant composite transposon as well as the role of gene transfer between gram-positive and gram-negative bacteria for the acquisition of antibiotic resistance determinants in chronic, mixed infections is discussed.