Abstract

Pseudomonas aeruginosa is an opportunistic pathogen that can cause severe hospital-acquired infections, especially in immunocompromised hosts. P.aeruginosa is important for its resistance to antibiotics. Pathogenic microorganisms have to face hostile environments while colonizing and infecting their hosts. Unfortunately, they can cope with it and have evolved a number of complex secretion systems, which direct virulence factors either at the bacterial cell surface into the environmental extra cellular milieu or into the host cell cytosol. The Gram-negative opportunistic human pathogen Pseudomonas aeruginosa possesses abroad panel of secretion systems. Five of the six secretion machines characterized in Gram-negative bacteria are at P. aeruginosa disposal, sometimes in several copies. All these machines are dedicated to the specific secretion of exoproteins, which display various activities useful for bacterial adaptation to the environment or for bacterial pathogenicity. In this study inhibitory effects of Satureja khuzestanica extract, an endemic plant of Iran, on the expression level of T2SS, and T3SS genes in P. aeruginosa were investigated. For this purpose, MIC was determined for P. aeruginosa. Then, bacteria were treated with S. khuzistanica extract. T2SS, T3SS and gyrA genes expression in treated and non-treated bacteria, before and after treatment was evaluated using RT-PCR technique. Surprisingly, the expression level of T2SS and T3SS genes was decreased in the presence of S. Khuzestanica. However, the expression of gyrAgene that was used as an internal control was not altered before and after treatment with this herb. Based on the results; S. Khuzestanica could play a, major role in lowering the P. aeruginosa resistance to drugs, by reducing T2SS, T3SS genes expression. According to results of current research we hope in future be used it to the clinic with a wider range as a complementary therapy and also for surgery operation or ointment.