GENETIC AND MOLECULAR ANALYSIS OF PIP417 AND PIP419 - BACTEROIDES PLASMIDS ENCODING 5-NITROIMIDAZOLE RESISTANCE

This report describes a genetic and molecular analysis of two transferableBacteroides plasmids, pIP417 and pIP419, which carry genetic determinants conferring low-level resistance to 5-nitroimidazoles. The restriction endonuclease cleavage sites for each plasmid were localized. The NiR genetic determinants of pIP417 and pIP419 plasmids have been cloned into theBacteroides cloning vector pBI191 (C.J. Smith,J. Bacteriol.164, 294-301, 1985) as PvuII and Sau3A fragments, respectively. Both inserts had different restriction sites and did not cross-hybridize by Southern blot analysis. Genetic data obtained by cloning into pBI191 clearly show that thePvuII-generated fragments A (Rep) and B (Mob) of pIP417 are involved in plasmid replication and transfer, respectively. Although encoding resistance to the same antibiotic, both plasmids appeared different with regard to the 5-nitroimidazole resistance and replication genetic determinants. However, they share a homology in a region involved, at least in one case, in plasmid transfer. Considering the spontaneous high level of resistance to 5-nitroimidazole inEscherichia coli, this work, based on direct gene cloning intoBacteroides, demonstrates the value of such an approach. © 1992 Academic Press, Inc. All rights of reproduction in any form reserved.