Introduction: Gardnerella vaginalis is the main etiological agent of bacterial vaginosis (BV), this bacteria has been classified in eight biotypes based on the production of beta-galactosidase, hydrolysis of hippurate and lipase, additionally produces several virulence factors, among them vaginolysin (VLY) is the most important. VLY is a pore-forming cytolysin that damages cells structurally and functionally through the binding with the human receptor CD59 and cholesterol. To date there are no studies linking the production of VLY with the biotypes of these bacteria, which was the main objective of this study.

Methodology 90 strains of G. vaginalis were analysed, of which 60 were associated with normal flora and 30 with BV, biotyping was performed according to the scheme proposed by Piot et al. 1984. Dot Blot and haemagglutination evaluated VLY production and lytic capacity. The Dot Blot results were analysed densitometrically and classified as low, moderate and abundant. The lytic capacity was expressed in percentage.

Results We identified in the analysed population biotypes 1, 2, 5 and 6 of G. vaginalis. In the group with normal flora: biotype 1 was identified in 22%, biotype 2 in 12%, biotype 5 in 32% and biotype 6 in 35%, while in the group associated with BV biotype 1 was identified in 33%, biotype 2 in 10%, biotype 5 in 10% and biotype 6 in 47%. Low production of VLY was observed in 48%, moderate in 37% and abundant in 15% of the cases in the group with normal flora. While in the group with BV low production was observed in 30%, moderate in 43% and abundant in 27% of the cases. Additionally, we observed that the biotype 6 (normal flora) and 2 (BV) have the highest lytic capacity, without finding significant differences between both groups.

Conclusion We isolated the biotypes 1, 2, 5, and 6 in both study groups. The biotypes associated with VB showed higher production of vaginolysin and a greater lytic capacity. These results suggest that VLY produced by biotypes of G. vaginalis could be a key factor in the establishment and maintenance of BV.