Rhus coriaria extracts inhibit quorum sensing-related virulence and biofilm production in drug-resistant Pseudomonas aeruginosa recovered from burn wounds.

Objectives: Numerous studies have confirmed sumac's ability to inhibit pathogens and even eradicate chronic drug-resistant infections. Current research was conducted to demonstrate the action of various sumac extracts at sub-inhibitory concentrations in modulating pathogen-related characteristics instead of killing them. Materials and Methods: The influence of sumac extracts on the quorum sensing dependent virulence of multidrug-resistant isolates of Pseudomonas aeruginosa recovered from burn wounds was considered by detecting the effect on biofilm development, various virulence factors, and expression of bacterial exotoxin A and quorum sensing related genes. Results: Experiments to characterize and measure sumac extract's impact on the P. aeruginosa growth, biofilm, exoproteases, pyocyanin, motility, and the quorum sensing networks revealed that all studied characteristics were reduced by concentrations below inhibition without affecting bacterial growth. Furthermore, the expression of exotoxin A, rhl, and las glucons was declined or even inhibited by lower levels of sumac fruit fractions. Conclusion: The findings revealed that sumac fights infections either by its inhibitory effect on the bacterial cells or by reducing bacterial signaling and virulence by disruption of the bacterial signal system.

Low concentrations of local honey modulate Exotoxin A expression, and quorum sensing related virulence in drug-resistant Pseudomonas aeruginosa recovered from infected burn wounds.

OBJECTIVES: Honey's ability to kill microorganisms and even eradication of chronic infections with drug-resistant pathogens has been documented by numerous studies. The present study is focused on the action of honey in its sub-inhibitory levels to impact on the pathogens coordinated behaviors rather than killing them. MATERIALS AND METHODS: The impact of local honey on the quorum sensing related virulence of multidrug resistant Pseudomonas aeruginosa burn isolates was investigated by detection its effect on the virulence, biofilm formation and expression of quorum sensing related and exotoxin A genes. RESULTS: Experiments to characterise and quantify the impact of honey on the P. aeruginosa quorum sensing networks showed that the expression of exotoxin A ( ETA), las and rhl glucons reduced by low concentrations of honey including the associated virulence factors. CONCLUSION: Our results indicated that honey fights infections either by its bactericidal components which vigorously kill cells or by weakening bacterial coordination and virulence through interruption of quorum sensing system.