Comparison of antibacterial properties of prodigiosin pigment extracted from Serratia marcescens and carotenoid pigment Rhodotorula glutinis on Pseudomonas aeruginosa and Acinetobacter

Identifying new antimicrobial compounds is a way to deal with spread of bacterial resistance, which bacterial pigments are one of the antimicrobial compounds. The most common causes of treatment-resistant infections in humans and animals are bacteria such as Pseudomonas aeruginosa and Acinetobacter. The purpose of this research is to compare the antibacterial properties of prodigiosin pigment from Serratia marcescens and carotenoid pigment from Rhodotroella glutinis on Pseudomonas aeruginosa and Acinetobacter. After separating the bacteria and identifying them, by using differential tests, Serratia marcescens (PTCC: 1111) and Rhodotrola (PTCC: 5256) pigments were extracted through chromatography. In order to evaluate the effect of different dilutions of pigments on bacteria, sterile 96-well microplates were used and the minimum inhibitory concentration (MIC) and minimum lethal concentration (MBC) were determined by broth microdilution method. Welling was done with different volumes of pigments. Out of the 50 burn wound samples, 26 samples were positive for the presence of two bacteria, all of which were sensitive to colistin and resistant to gentamicin, imipenem, ceftazidime, amikacin and ciprofloxacin. After the effect of both pigments on Pseudomonas aeruginosa, the highest MBC observed was 25 microliters, and after the effect of prodigiosin pigment on Acinetobacter bacteria, the highest MBC was 6.25 microliters, and this value for carotenoid pigment was 25 microliters. In welling, the largest average diameter of the zone of inhibition related to two pigments against these bacteria was observed in the volume of 200 microliters