LACTOBACILLI FROM WOMEN WITH OR WITHOUT BACTERIAL VAGINOSIS AND OBSERVATIONS ON THE SIGNIFICANCE OF HYDROGEN-PEROXIDE

Lactobacilli are the predominant organisms in the healthy vagina where as there are few or none in the vagina of women with bacterial vaginos is (BV). In a study of 155 women, these organisms were isolated from t he vagina of 47 (88 . 6 per cent) of 53 healthy women, and from 30 (29 . 4 per cent) of 102 women with BV, the dominant species being L. aci dophilus and L. plantarum. The proportion of hydrogen peroxide (H2O2)- producing strains of these two species, 31 (72 per cent) of 43 isolate d from healthy women, was similar to the proportion of such strains, 1 4 (77 per cent) of 18 isolated from women with BV. Furthermore, the to tal number of H2O2-producing lactobacilli isolated from the healthy wo men, that is 38 (61 per cent) of 62 isolates of H2O2-producers, was no t greatly different from 31 (73 per cent) of 42 isolates recovered fro m the women with BV. Overall, the number of colonies of lactobacilli i solated on Rogosa agar and the amount of H2O2 produced by them were no t much different whether the organisms were recovered from healthy wom en or women with BV. Bacteria-free supernates containing H2O2 produced by growth of several strains of lactobacilli, in addition to micro-mo lar solutions of H2O2 and known concentrations of lactic acid and urea , had no inhibitory effect on Bacteroides ureolyticus, Pievotella mela ninogenica (B. melaninogenicus) and Bifidobacterium spp. However, Gard nerella vaginalis and Mobiluncus spp. were weakly-inhibited by the cel l-free supernates and G. vaginalis by solutions of nitrate and catalas e. As these organisms were also resistant to known concentrations of a nalytical H2O2, the positive inhibitory reaction from these fluids was probably due to an inhibitory substance in the supernate other than H 2O2 which deserves further investigation. These observations suggest t hat H2O2 per se may be less bactericidal than previously thought in th e control of intra-vaginal proliferation by BV-related bacteria in viv o.