Effect of Origanum vulgare extract against Pseudomonas aeruginosa carbapenems resistant strains.

BURATTI C., ; CABRERA M., ; SALINAS IBÁÑEZ A.; ARISMENDI SOSA AC., ; CORREA S., ; RIGO H.; VEGA AE

Merlo

Congreso; XXXV Reunion Cientifica Anual Sociedad Biologia de Cuyo; 2017

Sociedad de Biología de Cuyo

Pseudomonas aeruginosa is a nosocomial pathogens that cause hard-to-treat infections. Carbapenems, meropenem and imipenem, are the drug of choice for the treatment of infections due to multi drug resistant P. aeruginosa. Chromosomal mechanism of imipenem resistance is the loss of porin oprD, and the over expression of efflux pumps contributing to meropenem resistance. Origanum vulgare is an aromatic herb used as flavoring agent in foods. The aim was to investigate the effect of oregano extract (OE) against P. aeruginosa carbapenems resistant strains. A total of 30 P. aeruginosa strains isolated in the Central Hospital San Luis from clinical samples and ATCC 27853 reference strain were used. Carbapenems susceptibility was determined by disk diffusion method. Molecular characterization of carbapenems resistance was determined byRT-PCR assay using MexA, MexB, MexR, OprM, OprD and housekeeping rPSL genes. The antimicrobial effect of EO on ten P. aeruginosa strains was performed by broth microdilution method according to CLSI. EO was diluted to obtain the final concentrations of 100 to 0.8mg/mL. Minimal inhibitory concentration (MIC) was determined as the smallest amount of extract needed to inhibit the visible growth of the microorganism. EO showed MIC values ranged 6 to 12.5 mg/ml against five P. aeruginosa sensible strains tested; while 60% resistant strains showed MIC values ranges 6 to 12.5 mg/ml and over expression of efflux pumps. One resistant strain showed 1.5 MIC value and both resistance mechanism. The results suggest that EO could be used for treatment of infections caused by P. aeruginosa resistant strains