TRANSFER OF MACROLIDE-LINCOSAMIDE-STREPTOGRAMIN-B (MLS) RESISTANCE INCLOSTRIDIUM-DIFFICILE IS LINKED TO A GENE HOMOLOGOUS WITH TOXIN-A ANDIS MEDIATED BY A CONJUGATIVE TRANSPOSON, TN5398

An MLS resistance gene designated ermBZ, from a toxigenic Clostridium difficile strain (630) could be transferred between C. difficile strai ns, and to and from Bacillus subtilis. The intergeneric transfer occur red in the absence of any detectable plasmid DNA and the element respo nsible for gene transfer entered the recipient's chromosome, behaviour which is characteristic of a conjugative transposon. The element was designated Tn5398 and was found in six C. difficile strains. Tn5398 co uld be transferred to the non-toxigenic strain C. difficile CD37 which lacks the genes for toxins A and B. Transconjugants from both C. diff icile and B. subtilis that had received the ermBZ gene also acquired a sequence of DNA that was homologous to the part of the toxin A gene t hat coded for the C-terminal repeat region.