LAUSR

Bacterial vaginosis is the most common gynecological disorder affecting women of reproductive age. Bacterial vaginosis is frequently associated with the development of a Gardnerella vaginalis biofilm. Recent data indicates that G. vaginalis biofilms are more tolerant to antibiotics and are able to incorporate other bacterial vaginosis -associated species, yielding a multi-species biofilm. However, despite its apparent role in bacterial vaginosis, little is known regarding the molecular determinants involved in biofilm formation by G. vaginalis. To gain insight into the role of G. vaginalis in the pathogenesis of bacterial vaginosis, we carried out comparative transcriptomic analysis between planktonic and biofilm phenotypes, using RNA-sequencing. Significant differences were found in the expression levels of 815 genes. A detailed analysis of the results obtained was performed based on direct and functional gene interactions. Similar to other bacterial species, expression of genes involved in antimicrobial resistance were elevated in biofilm cells. In addition, our data indicate that G. vaginalis biofilms assume a characteristic response to stress and starvation conditions. The abundance of transcripts encoding proteins involved in glucose and carbon metabolism was reduced in biofilms. Surprisingly, transcript levels of vaginolysin were reduced in biofilms relative to planktonic cultures. Overall, our data revealed that gene-regulated processes in G. vaginalis biofilms resulted in a protected form of bacterial growth, characterized by low metabolic activity. This phenotype may contribute towards the chronic and recurrent nature of bacterial vaginosis. This suggests that G. vaginalis is capable of drastically adjusting its phenotype through an extensive change of gene expression.Vaginal infection: Gene activity protects biofilmsAltered gene activity may promote chronic and recurrent infections in the most common gynecological disorder in women of reproductive age. Bacterial vaginosis (BV) frequently involves the formation of biofilms by Gardnerella vaginalis bacteria. Nuno Cerca and colleagues at the University of Minho in Portugal, with co-workers elsewhere in Portugal and in the USA, studied changes in gene activity in BV biofilms. Their results linked differences in the activity of 815 genes to an ability of the bacteria to enter a protected form of growth when producing biofilms. The differences included increased activity of specific genes associated with antibiotic resistance. This insight into the bacterial ability to undergo drastic changes in gene activity could guide work to understand chronic and recurrent BV. It may also lead to new ways to treat this common and troublesome condition.