Potential effects of pyocyanin on the antibacterial action of ampicillin and cefotaxime against human pathogenic bacteria

Abstract

Abstract Pyocyanin (PCN) is a blue–green pigment mainly produced by Pseudomonas aeruginosa. It has antimicrobial effects on a variety of organisms. Ampicillin (AMP) and cefotaxime (CTX) are widely used against bacterial pathogens as important antibacterial agents. The effect of PCN on the antibacterial action of AMP and CTX has been studied. PCN from P. aeruginosa was extracted by chloroform method. Two PCN concentrations (2 and 4 µg/ml) were combined separately with a variety of AMP and CTX concentrations. Change in the antibacterial activity of AMP and CTX against 14 isolated pathogenic bacteria after combination has been investigated. The antibacterial activity of AMP decreased against 7 bacterial isolates when mixed with 4 µg/ml of PCN, while this activity increased against the majority of bacteria after mixing with 2 µg/ml. CTX activity was also reduced against 12 bacterial isolates by 4 µg/ml of PCN, while it was not generally affected by 2 µg/ml. in conclusion; PCN had variable effects on the antibacterial activity of AMP and CTX, which varied mainly between decreased activity and absence of effects. A low concentration of PCN was more effective in increasing the action of AMP, but had no effect on the action of CTX.