An engineered phage endolysin could offer a therapy for recurrent bacterial vaginosis (BV), a disease for which no effective treatment option exists, according to a study.
BV, a recurrent infection affecting women of reproductive age group, is caused mainly by Gardnerella bacteria. These anaerobic bacteria destabilize the healthy vaginal microbiome by suppressing and overgrowing beneficial lactobacilli. Additionally, Gardnerella initiates the development of a biofilm on the vaginal epithelium that further facilitates the growth of harmful anaerobic bacteria and protects them from antibiotic treatment.
The novel drug candidate not only lyses any Gardnerella strain in vitro but also fully dissolves the bacteria-dominated biofilm in vaginal samples of patients, who had previously endured years of unsuccessful antibiotic treatment, shows data from the study published by PhagoMed Biopharma GmbH, a Vienna-based biotech company.
The results demonstrate that phage endolysins inhibit the in-vitro growth of any tested Gardnerella strain already at a concentration in the low microgram/millilitre range, well below the minimum inhibitory concentration (MIC) of the most commonly used antibiotic against BV, metronidazole (MDZ). In contrast, 60% of Gardnerella strains were fully resistant to MDZ.
Furthermore, due to the high specificity of the endolysin, the beneficial microbiome of the vagina remains unharmed by the treatment.
Endolysins are proteins originally encoded by phages – viruses that only infect bacteria. Phages multiply by injecting their DNA into the bacteria and reprogramming the cells to produce new phages. As soon as sufficient phage particles have been produced by the bacteria, the phages dissolve the cell wall with the help of special enzymes – including endolysins. Endolysins cleave the bacterial cell wall which leads to instant cell death.