Results of a new US study indicate that whichever strain of Streptococcus pneumoniae is in place in a mammal’s tissues first is more likely to thrive than Strep “latecomers”.
Senior study author Jeffrey Weiser, MD, Chair of the Department of Microbiology at NYU Langone Health, said: “With Strep infections costing the lives of nearly a million children under five each year globally, we are urgently seeking new ways to defeat bacteria by learning more about how they compete with each other.”
Previous studies have established that bacteria engage certain mechanisms only when bugs have multiplied beyond a population density threshold, known as a “quorum”.
The new study suggests that among the mechanisms initiated by a Strep quorum is release of two toxins – choline binding protein D (CbpD) and the competence-induced bacteriocins (CibAB). These toxins kill intruding, competing strains. The owners, however, also release other factors that protect them from their own toxins. Their newly arriving relatives, not yet having a quorum, do not yet have their defenses in place.
