Researchers at the Institute of Experimental Medicine (St. Petersburg) have developed a new vaccine against group B streptococcus (Streptococcus agalactiae). This microorganism causes infections in the respiratory tract and vagina, as well as the colon and urethra, and can be deadly to newborns, as reported by chrdk.ru, an online portal, citing a scientific article published in PLoS ONE, a journal.
For Streptococcus agalactiae vaccine, the scientists used the Bac protein found on the surface of this bacterium. The natural source of Bac are group B streptococci, but handling them poses the risk of infection by these microorganisms. Therefore, the scientists have introduced the gene encoding this protein into safer microorganisms, such as Enterococcus, which are part of probiotics.
The introduction of enterococci with BAC protein signaled the presence of an alien entity to the immune system of experimental animals. Given that no mice had died from the infection, the vaccination allowed to successfully fight against Streptococcus agalactiae.
According to scientists, the versatility of their version makes it a better option than many existing vaccines. Most researchers base their vaccines on polysaccharides taken from the surface of Streptococcus agalactiae, and the structure of these substances changes rapidly. Therefore, these drugs will “tell” the immune system only about some strains of group B streptococcus, while an infection by others will still be possible.
Russian researchers used enterococci that can grow at high oxygen concentrations. Typically, in such cases, the scientists use Lactobacillus that has a substantially narrower range of comfortable living conditions. This means that the experimental vaccine from St. Petersburg may be, in addition, more stable than its competitors.