Study: Does strain matter? G. vaginalis

A study has found eight distinct biotypes of Gardnerella vaginalis in samples taken from women with bacterial vaginosis, equalling out to 32 strains. The strains all showed different characteristics, including how well they stuck to the vaginal epithelial cells and if they produced a biofilm or not.

Four of the biotypes were predominant. There was no correlation between the biotype and virulence factors, with virulence factors not associated with a single biotype. What this means in English is that they couldn’t find the biotype that ruled the other biotypes; the top four all seemed to be just as much involved in BV as each other, though biotypes 3, 4, 6 and 7 were present less.

Biotype 1:  25 per cent
Biotype 2: 22 per cent
Biotype 5:  16 per cent
Biotype 8:  16 per cent

Key findings:

• Almost 70 per cent of the strains showed ‘relatively better adherence’, which equates to over 25 ‘bacteria’ per vagina cell
• Over 70 per cent produced a biofilm
• 75 per cent showed relatively high surface hydrophobicity (more than 50 per cent)
• 88 per cent produced phospholipase C
• Just under 15 per cent were protease positive

Eight of the women were asymptomatic and 24 had vaginal discharge, with no correlation found between asymptomatic women and those with abnormal discharge, however biotypes 1, 2, 5 and 8 were more common in those women with abnormal discharge, but not by much.

Reference

Udayalaxmi J, Bhat GK, Kotigadden S, Biotypes and virulence factors of Gardnerella vaginalis isolated from cases of bacterial vaginosis’, Indian Journal of Medical Microbiology, 2011, Issue 29, Page 165-168