Antimicrobial activity of prodigiosin is attributable to plasma-membrane damage

Abstract

The bacterial pigment prodigiosin has various biological activities; it is, for instance, an effective antimicrobial. Here, we investigate the primary site targeted by prodigiosin, using the cells of microbial pathogens of humans as model systems: Candida albicans, Escherichia coli, Staphylococcus aureus. Inhibitory concentrations of prodigiosin; leakage of intracellular K ions, amino acids, proteins and sugars; impacts on activities of proteases, catalases and oxidases; and changes in surface appearance of pathogen cells were determined. Prodigiosin was highly inhibitory (30% growth rate reduction of C. albicans, E. coli, S. aureus at 0.3, 100 and 0.18 μg ml, respectively); caused leakage of intracellular substances (most severe in S. aureus); was highly inhibitory to each enzyme; and caused changes to S. aureus indicative of cell-surface damage. Collectively, these findings suggest that prodigiosin, log P 5.16, is not a toxin but is a hydrophobic stressor able to disrupt the plasma membrane via a chaotropicity-mediated mode-of-action.

Antimicrobial activity in culturable gut microbial communities of springtails

“…The growth‐inhibiting activities exerted by Serratia marcescens have also been observed before, and this species is known to synthesize the red antimicrobial compound prodigiosin (Suryawanshi et al . ).…”

Natural biocide cocktails: Combinatorial antibiotic effects of prodigiosin and biosurfactants

“…marcescens , the prodigiosin biosynthetic pathway is encoded in a 21 kb gene cluster consisting of 14 pig genes [ 8 ]. Prodigiosin, which is produced from the precursors 2-octenal and proline in a complex bifurcated pathway, has several relevant properties such as immunosuppressive and anticancer activities toward different types of human cancer cells [ 9 – 11 ], as well as antimicrobial effects against Gram-positive and Gram-negative bacteria [ 12 – 15 ]. Several molecular mechanisms causing the antibiotic effects of prodigiosin are currently discussed, e.g., membrane potential alteration via anion symport [ 16 ], membrane damage [ 15 ], phototoxicity [ 17 ], and formation of reactive oxygen species (ROS) [ 18 ].…”

An IgaA/UmoB Family Protein from Serratia marcescens Regulates Motility, Capsular Polysaccharide Biosynthesis, and Secondary Metabolite Production

“…Both prodigiosin and serratamolide are reported to have broad-range antimicrobial activity, and serratamolide promotes swarming motility, a behavior that may allow the bacterium to become less susceptible to antibiotics and move into more favorable microenvironments (8,(12)(13)(14)(15)(16)(17). Serratamolide from S. marcescens is hemolytic and was demonstrated to enable bacteria of different genera to evade phagocytosis by neutrophils in vitro, together suggesting that it may be a virulence factor and impact polymicrobial infections (18,19).…”