Does Streptococcus mitis, a neonatal oropharyngeal bacterium, influence the pathogenicity of Pseudomonas aeruginosa?

Microorganisms in a biofilm might promote or suppress each other. We previously found that Pseudomonas aeruginosa (P. aeruginosa) and the normal colonized bacteria in the oropharynx, Streptococcus mitis (S. mitis), were the most common bacteria in the biofilm found on newborns' endotracheal tubes. Here, we found that S. mitis enhanced the adhesion and biofilm formation of P. aeruginosa. Furthermore, it alleviated the immune response induced by P. aeruginosa. These findings remind us that we should not ignore the role of traditionally viewed non-pathogenic bacteria in biofilms and provide new insights into exploring bacterial interaction mechanisms in biofilm related infections.