Original Article: https://doi.org/10.1371/journal.pbio.3000788
- Bacteria are normally present in healthy vaginas.
- Imbalances of the various types of bacteria in the vagina can lead to an infection called bacterial vaginosis (BV).
- Women with BV are more likely to be populated by possible pathogens which includes Fusobacterium nucleatum.
- Fusobacterium nucleatum is an oral commensal pathogen linked with a wide range of human diseases.
- Fusobacterium nucleatum plays a role in periodontal disease and also linked with intrauterine infection and preterm birth.
- However, the conditions and mechanisms supporting pathogen colonization during microbial imbalances of the vagina remain unclear.
- Sialidases are group of enzymes which mainly catalyses the splitting of terminal sialic acids from complex carbohydrates on glycoproteins or glycolipids.
- The study demonstrates that sialidase activity promoted F. nucleatum food obtaining and growth on mammalian sialoglycans.
- Sialoglycans is a nutrient resource that was otherwise not accessible because of the lack of endogenous F. nucleatum sialidase.
- In mice with sialidase-producing vaginal microbes, mutant F. nucleatum unable to consume sialic acids was weakened in vaginal colonization.
- The experiments in mice also discovered that F. nucleatum may also help back to the community by fortifying sialidase activity which is a biochemical feature of human dysbiosis.
- Using human vaginal microbiome, the study show that F. nucleatum assisted strong outgrowth of Gardnerella vaginalis.
- Gardnerella vaginalis is a major sialidase producer and one of the most plentiful organisms in BV.
- The results explain that mutually beneficial relationships between vaginal bacteria support pathogen colonization and may help maintain features of microbial imbalances.
- The findings challenge the dogma that the absence of healthy lactobacilli is the sole mechanism that creates an allowable environment for pathogens during microbial imbalances of the vagina.
- Given that F. nucleatum are common in the human mouth, the study also suggests a possible mechanism underlying links between microbial imbalances of the vagina and oral sex.