Pyrithione biocide interactions with bacterial phospholipid head groups

Abstract

Sodium pyrithione and zinc pyrithione (NaPT and ZnPT, respectively) are antimicrobial agents widely used in both the cosmetics and fuel industries. They are also utilized in the mining industry because of their metal chelating properties. They have been shown to depolarize membrane electropotential in fungi and are also known to inhibit fungal and bacterial substrate transport processes. Recent work has shown that both pyrithiones cause the leakage of intracellular material (potassium ions and O.D.260nm absorbing material) from exposed bacterial cells. The work here reports studies on the interactions between the pyrithiones and the bacterial phospholipid head group structures, at both a practical and a theoretical level, utilizing tube dilution neutralizer studies, scanning spectrophotometry and molecular modelling. The tube dilution neutralizer studies exhibited a decrease in minimum inhibitory concentration (MIC) for both pyrithiones in the presence of extracellular phosphatidyl‐ethanolamine and EDTA. Scanning spectrophotometry exhibited the chelation of the central zinc atom from the ZnPT chelate by the addition of EDTA. Molecular modelling studies exhibited the chelation of the phosphatidyl‐ethanolamine head group by ZnPT. Zinc pyrithione also exhibited an interaction with the ammonium tail of the head group structures. Sodium pyrithione exhibited electrostatic interactions with the phospholipid head groups in the molecular modelling studies.

Antimacrofouling Efficacy of Innovative Inorganic Nanomaterials Loaded with Booster Biocides

“…Sub-lethal concentrations of ZnPT also activate the antioxidant protective mechanism, including an increased activity of antioxidant enzymes [25,41]. Several authors have connected ZnPT impairment to the uptake of zinc by mitochondria, the binding of ZnPT to the membrane phospholipids [42], and disruption of the membrane electrochemical gradient (due to the inhibition of the membrane proton-linked ATPase) [43].…”

Immunotoxicity in ascidians: Antifouling compounds alternative to organotins—IV. The case of zinc pyrithione

“…This finding is in agreement with previous observations by Lamore and Wondrack (2011) in cultured human keratinocytes based on quantitative fluorescence microscopy and inductively coupled plasma mass spectrometry (ICP-MS). According to the model proposed by Dinning et al (1998), ZnP can initially act at the level of the cell membrane. The association between ZnP and the heads of phospholipids causes a break in the lipid layer.…”

“…Due to its excellent chelant properties, ZnP is an active metal complex, acting in particular on biological membranes (Dinning et al, 1998). In addition, its low water solubility (8 μg/l according to Omae, 2003), with a 0.9 octanol-water partition coefficient (HSE, 2003), is responsible for its high stability and lipophilicity, which make it a good substitute for organotins in antifouling paint formulations.…”

Pseudomonas aeruginosa PAO1 Resistance to Zinc Pyrithione: Phenotypic Changes Suggest the Involvement of Efflux Pumps

“…Such co-regulation is seen when the bacteria is subjected to stress [10]. Exposure of bacteria to a powerful antimicrobial like ZnPT that has multiple antimicrobial mechanisms [8,10] is considered stressful.…”