Aim: The activity of chitosan microparticles (CM) was examined using a matrix of conditions in order to assess the efficacy of CM as a mitigation against various strains of Salmonella enterica in agricultural water.
Methods and results: Different concentrations of CM (0, 0·01, 0·1, 0·2, 0·3% w/v) were examined for antimicrobial activity against log vs stationary phase cells of Salmonella and at different conditions of temperature, salinity and pH. Results showed greatest activity with 0·3% CM at pH 7, 25-37°C without additional of salt. Significant reductions in Salmonella levels were also achieved in natural pond water, although decreases were reduced compared to sterile water. All serotypes were sensitive to CM, with minimal inhibitory concentrations ranging from 0·0031 to 0·0250% w/v. Phylogenic analysis of Javiana strains showed increased resistance appeared in multiple genetic lineages.
Conclusion: Conditions demonstrating greatest CM activity were compatible with agricultural practices. Although sensitivity to CM varied among Salmonella strains, all strains were sensitive under conditions examined in this study.
Significance and impact of the study: This research indicated that CM, a natural compound with minimal environmental impact, could be an effective alternative for mitigating Salmonella in agricultural water applications.
Keywords: Salmonella enterica; agricultural water; chitosan; mitigation; multilocus sequence typing; phylogenetic tree.
© 2017 The Society for Applied Microbiology.