The Effect of Streptococcal Pyrogenic Exotoxin Type A (SpeA) on the Formation of Streptococcus pyogenes Biofilm.

Abstract

The effect of recombinant streptococcal (Streptococcus pyogenes) exotoxin type A (rSpeA) on biofilm formation by S. pyogenes was studied using a laboratory strain of serotype M30 and five non-typeable clinical strains of S. pyogenes. The inhibition of bacterial growth was observed during both the initial formation stage and within established biofilms. It was shown that under the action of rSpeA on biofilm formation, the growth of strain M30 was inhibited by 1.6 times and the growth of strains 1, 2, and 3 was inhibited by 2.3, 1.3, and 1.4 times, respectively. For strains 4 and 5, the inhibition was practically absent. Application of SpeA to the formed biofilm of streptococcal strains produced a more pronounced inhibitory effect: 2.5-fold for strain M30, and 5.5-, 3.4-, and 4.2-fold for strains No. 2, 3, and 5, respectively. These findings suggest that SpeA being a superantigen can also destroy streptococcal biofilms promoting the spread of bacteria in the body and leading to generalization of the infectious process.