Co-infection with Pseudomonas aeruginosa impacts virulence of Staphylococcus aureus and intensifies the severity of infection.

Multi-specie infections display diverse interactions among pathogens that influence the severity of disease. Staphylococcus aureus and Pseudomonas aeruginosa are the two most important opportunistic, nosocomial and drug-resistant pathogens. Poly-infections due to S. aureus and P. aeruginosa are more destructive and result in worse patient outcome than mono-infection. The two organisms are commonly isolated from cystic fibrosis respiratory cultures. Studies demonstrated that S. aureus pre-colonization among cystic fibrosis patients is a hazardous for beginning P. aeruginosa aviation route infection. This work meant to explore the impact of P. aeruginosa on the destructiveness of S. aureus and the level of disease's seriousness by utilizing in-vitro co-culture and host cell model. The outcomes showed that P. aeruginosa outcompetes and suppresses the growth of S. aureus when co-cultured. The host factors expression profile indicated elevated expression of TNFα, IL-6 and IL-12, recommending the unique mechanism of host cell healing inhibition by multispecies. Co-infection resulted in significant increase in IL-8 together with the 10-fold induction of iNOS expression when contrast with S. aureus mono-infection. This indicates that the presence of P. aeruginosa heads the infection towards more severity and complications and delays cell healing process.