In vitro Interaction of Certain Antimicrobial Agents in Combination with Plant Extracts Against Multidrug-resistant Pseudomonas aeruginosa Strains

This study has been carried out to evaluate the possible In vitro interaction between ethanolic extracts of Rus coriaria (seed), Sacropoterium spinosum (seed) and Rosa damascena (flower) and certain known antimicrobial drugs including oxytetracycline HCl, penicillin G, cephalexin, sulfadimethoxine as sodium and enrofloxacin. Synergy testing of these extracts and antibiotics was carried out against 3 multidrug-resistant Pseudomonas aeruginosa strains using microdilution method. Results of this study showed that there is a decrease in the MIC in case of combination between ethanolic plant extracts and test antimicrobial agents. The most interesting result that the combination between R. coriaria and these antibiotics, which showed a high decrease in MIC and a strong bactericidal activity against these strains. These results may indicate that combinations between R. coriaria extract and these antibiotics could be useful in fighting emerging drug-resistance P. aeruginosa, this may due to that R. coriaria extract contain natural inhibitors working by different mechanisms or inhibiting efflux pumps. Now we have experiments underway leading to the identification of the active molecules present in R. coriaria. Further, in vivo experiments are needed to confirm Pseudomonal protection.