METAL ACCUMULATION AND VANADIUM-INDUCED MULTIDRUG-RESISTANCE BY ENVIRONMENTAL ISOLATES OF ESCHERICHIA-HERMANNII AND ENTEROBACTER-CLOACAE

Contaminated soils from an oil refinery were screened for the presence of microorganisms capable of accumulating either nickel, vanadium, or both metals. Three strains of bacteria that belonged to the family En terobacteriaceae were selected. Two of them were Escherichia hermannii strains, and outer membrane profile (OMP) analysis showed that they w ere similar to a strain of clinical origin; the other one was an Enter obacter cloacae strain that differed from clinical isolates. The selec ted bacteria accumulated both nickel and vanadium. Growth in the prese nce of vanadium induced multidrug resistance phenotypes in E. hermanni i and E. cloacae. Incubation with this metal changed the OMP profile o f E. hermannii but did not produce variations in the expression of the major OMPs of E. cloacae.