Relation of the drug-efflux mechanism to streptomycin and gentamicin-resistance of Prevotella intermedia

Abstract

I studied whether the drug-efflux mechanism is related to streptomycin (SM) and gentamicin (GM) resistance in anaerobic gram negative rod Prevotella intermedia MA1 (MA1) and MA1-V2(V2).In MA1 24hrs after inoculation, the ratio of growth with treatment by with carbonyl cyanide m-chloro phenyl(CCCP)to growth without was 0.87.The ratios of growth with 32, 64 and 128μg / mL SM combined with 5μg / mL CCCP to the growth with SM alone (growth ratios)were 0.58, 0.45 and 0.58, respectively.These ratios with 5μg / mL CCCP and 32, 64 and 128μg / mL GM were 0.47, 0.51 and 0.43.There was growth inhibition of MA1 with exposure to CCCP alone.The growth ratios for V2 with 10μg / mL CCCP-SM or CCCP-GM were the same as those for MA1.The accumulations of SM and GM in MA1 and V2 cells whose growth ratio decreased with 5 to 10μg / mL CCCP were larger than those without CCCP.The cell strains whose growth ratio decreased after exposure to CCCP were frequently collapsed in transmission electron micrographs.These results suggest that the drug-efflux mechnism is closely related to the SM and GM resistance of Prevotella intermedia MA1 and MA1-V2.