Abstract

The inhibition of efflux pumps plays a role in combating the antimicrobial resistance (AMR). Antimicrobial resistance in Escherichia coli (E.coli) is caused by the AcrAB-TolC efflux system, which is a form of efflux pump. Mdf A is a putative membrane protein of 410 amino acids that belongs to the major facilitator superfamily of transport proteins. In this study capsaicin, a phyto-alkaloid was used as modulator of efflux pump in combination with tetracycline in tetracycline resistant E.coli. Antimicrobial sensitivity was carried out using standard disc diffusion method with appropriate controls. Tube dilution method was carried out for MIC and the turbidity was measured at 600nm. mRNA expression for the respective genes (Tol C, Mdf A, Nor E) were carried out by Real time PCR. There was no zone of inhibition for capsaicin and tetracycline when they were used alone, while there was significant increase in the zone of inhibition for tetracycline when it was combined with capsaicin. Turbidity of the culture decreased when tetracycline is used in combination with capsaicin. Use of phytochemicals like capsaicin, which is a known inhibitor of efflux pump, could interfere with efflux pumping of antibiotics in resistant bacteria. mRNA expression for Tol C is decreased, whereas for Mdf A and Nor E, it is increased when tetracycline is used in combination with capsaicin indicating the blocking of efflux pumps.

Keywords : Antimicrobial resistance, Tol C, Mdf A, Nor E, Escherichia coli