Molecular characterisation of emergent multiresistant Salmonella enterica serotype [4,5,12:i:-] organisms causing human salmonellosis

Salmonella multidrug-resistant clinical organisms identified as serotype [4 ,5,12:i:-] were typed using selected genetic procedures and compared with t yphimurium organisms collected in the same Spanish region. Results showed a low genetic heterogeneity among [4,5,12:i:-] organisms, which generated id entical ribotypes and similar but not identical XbaI PFGE, RAPD, and plasmi d profiles. Multidrug resistance could be eliminated by curing and seems to be mediated by 140-kb (spvC+) and 120-kb (spvC-) non-self-transferable pla smids. The [4,5,12:i:-] organisms fall into a single genetic lineage, which emerged in 1997 and presents a different degree of genetic relationship wi th typhimurium lineages. (C) 2000 Federation of European Microbiological So cieties. Published by Elsevier Science B.V. All rights reserved.