The effects of Staphylococcus aureus on the β-lactamase enzymes and virulence factors of Pseudomonas aeruginosa in lung disease

Abstract BackgroundPseudomonas aeruginosa and Staphylococcus aureus often lead to serious lung infections. This study aimed to investigate the role of Staphylococcus aureus in the expression of the β-lactamase enzymes and virulence factors of P. aeruginosa in the polymicrobial infections of the respiratory tract.ResultsIt was demonstrated that S. aureus reduced the viability of P. aeruginosa , particularly in the biofilm state. In addition, S. aureus decreased β-lactam resistance but increased resistance to tobramycin in the biofilm condition. Furthermore, S. aureus showed a positive effect on reducing resistance to meropenem, doripenem, ertapenem, and tobramycin (except PA-2) and on increasing pathogenicity in P. aeruginosa . Moreover, the gene expression levels for lasR/I and algD were increased in biofilm conditions. The levels of lasI were more prominent in the virulent strain than the β-lactamase producing strain. Furthermore, the expression of KPC was increased in all strains of P. aeruginosa.ConclusionIt was concluded that S. aureus has an inhibitory effect in polymicrobial infections by suppressing the β-lactamase genes and viability of P. aeruginosa and also cooperates with the biofilm-producing P. aeruginosa strains to increase pathogenicity and resistance to tobramycin.