The vaginal microbiology of 195 white women living in a subtropical climate and at three socio-economic levels was studied. Relationships were sought between microbiological results and clinical diagnoses of infectious conditions, and between the potentially pathogenic micro-organisms isolated from women and their social status. Candidiasis was the most common vaginal infection detected, particularly in university students. Sexually transmitted organisms and mixed infections (specimens which yielded more than one potentially pathogenic micro-organism) were more common in women from lower socio-economic levels. Haemophilus vaginalis was not common in either symptomatic or asymptomatic women. Certain changes in the composition of the normal flora could be correlated with the presence of potentially pathogenic micro-organisms in the vagina.
Twenty-one clinical isolates selected as H. vaginalis strains by currently used criteria (Dunkelberg, Skaggs and Kellogg, 1970b) and the type strain of H. vaginalis were studied in detail. Numerical taxonomy results divided the 22 strains into two major groups which merged at such a low level of similarity as to indicate a complete lack of systematic relationship. Eleven of the isolates grouped with the type strain and were identified as strains of H. vaginalis.
Both the Gram reaction of H. vaginalis and the nature of its cell wall have been the subjects of much controversy. The present study showed that the amino acid composition of the H. vaginalis cell wall, its cell wall profile, process of cell division and the appearance of its outer surface were all like those of typical Gram-positive bacteria although the cell wall was thin for a Gram-positive organism.
The data presented confirm that H. vaginalis cannot be classified in any existing genus and support the recent proposal of Greenwood and Pickett (1980) that H. vaginalis be transferred to a new genus Gardnerella. Contrary to the conclusions of Greenwood and Pickett (1980) however, it is concluded that the new genus should be classed within or closely associated with the Gram-positive bacteria.
Tests recommended for the presumptive identification of H. vaginalis were determined.