Incidence of tellurite resistance determinants among plasmids of different incompatibility groups

Twenty tellurite resistance (TeR) plasmids of IncH12, IncH13, and IncHII groups isolated from Enterobacteriaceae hybridized with the pMJ606 (IncHI2) TeR probe, whereas the promiscuous Pseudomonas IncP alpha plasmids hybridized with only the IncP alpha TeR probe (pDT1555). Neither of the TeR probes hybridized with the IncP2 Pseudomonas plasmids, which also specify TeR. None of the plasmids hybridized with pUM3, a plasmid carrying the arsABC genes that encodes resistance to arsenite, arsenate, antimony, and moderate levels of tellurite. These results show that the IncH12 TeR determinant is widespread in the Enterobacteriaceae and support the hypothesis that there are at least five distinct TeR determinants: (1) the telAB genes from the Escherichia coli chromosome; (2) IncHI2; (3) IncP2; (4) arsABC; and (5) the TeR determinants of IncP alpha plasmids.