Investigation of the impact of latex components on the survival of Pseudomonas aeruginosa

Control of biological spoilage is critical to the success of any coatings formulation. However, problems with bacterial resistance and biocide toxicity require changes in waterborne resin preparation and the resulting formulated product. Despite the importance of controlling bacteria-induced spoilage, very little research exists in the field. Critical aspects of biocide/bacteria/ coatings component interactions must be understood in order to improve the design of future biocides specific for coatings formulations. This research examines the impact of several common latex components and model biocide interactions on the survival of Pseudomonas aeruginosa. Systems were characterized using both traditional microbiological techniques and a novel high-throughput fluorescence technique. P. aeruginosa is recognized as the most problematic bacterium throughout the coatings industry because of its tendency to quickly develop resistance to both antibiotics and biocides. Designed experiments comparing formulations of 10% surfactant (by weight) reveal that formulation combinations rich in ionic surfactants promote bacterial growth compared to formulations with higher concentrations of nonionic surfactants. Studies also reveal that the ionic nature of the surfactant components has a strong impact on both the rate of P. aeruginosa survival as well as biocide efficiency, with gentamicin sulfate activity being strongly inhibited in formulations containing high concentrations of sulfated surfactant.