Subdivision of vaginal isolates of anaerobic curved bacteria based on genetic, morphologic, biochemical and gas-chromatographic/mass-spectrometric studies.

By DNA-DNA hybridization we could recognize two distinct groups of anaerobic curved rods (CR) that had been isolated from the vaginal content of women with bacterial vaginosis. On the basis of morphological studies these two groups correlated with one group of short, Gram-variable, curved rods (SCR) and another consisting of similar but somewhat longer rods (LCR). The SCR had up to four flagella per cell and the LCR up to eight. Among 79 biochemical tests, only tests for ONPG and arginine dehydrolase differentiated the two groups, SCR being positive and LCR negative. The gas chromatographic analysis of spent culture medium revealed that LCR, but not SCR, produced oxalacetic and oxalic acids. The groups were also differentiated by gas-chromatographic/mass-spectrometric patterns of certain cellular fatty aldehydes. Cell wall structure and presence of cytoplasmic inclusions did not distinguish SCR from LCR. On the basis of DNA-DNA hybridization values the SCR formed a more heterogeneous group than did LCR. Of all biochemical tests performed, only the production of alpha-galactosidase separated two strains of SCR that showed a low percentage of hybridization along with the rest of the SCR strains. Our study does not support a subdivision of SCR.