Proteomic approach to Pseudomonas aeruginosa adaptive resistance to benzalkonium chloride.

This study aimed to assess the membrane modifications in Pseudomonas aeruginosa after continuous exposure to increasing doses of benzalkonium chloride (BC). Two different concentrations were used, 0.9 and 12.0mM. Proteomic investigations revealed that the range of the outer membrane proteome alterations following continuous exposure is very low, i.e. about 10% and BC concentration dependent. Adapted cells revealed different expressions of key proteins frequently reported as involved in acquired resistance mechanisms. Porins (OprF and OprG) and lipoproteins (OprL and OprI) were underexpressed when the higher adaptation concentration (12 mM) was used. Some of these membrane alterations have been described as involved in the acquired resistance to antibiotics, suggesting possible common mechanisms between these two types of resistance. BIOLOGICAL SIGNIFICANCE: Results obtained after P. aeruginosa adaptation to benzalkonium chloride suggest that the bacterial adaptation to BC do not mobilize complete outer membrane systems. Though, we showed that adaptive resistance to BC promoted some changes in proteins previously described as involved in antibiotic resistance. These results contribute to the assumption that there are common resistance mechanisms, between adaptive and acquired resistance of P. aeruginosa.