INVESTIGATING THE IMPACT OF SILVER-STABILIZED HYDROGEN PEROXIDE ON SALMONELLA ENTERICA SEROVAR TYPHIMURIUM INTERACTIONS WITH ACANTHAMOEBA CASTELLANII

Candidate: Stefania Conforti
Supervisor: Dr. Stephen Liss

ABSTRACT

Bacteria may survive drinking water disinfection through survival and protection within Acanthamoeba species, which may facilitate the transmission of bacteria in water- and food-related environments. This thesis investigated the impact of silver-stabilized hydrogen peroxide (SSHP), a potential alternative drinking water disinfectant, on the host-pathogen interactions between Salmonella enterica serovar Typhimurium and Acanthamoeba castellanii. SSHP reduced the number of internalized S. Typhimurium within A. castellanii but increased the percentage of infected amoeba. In comparison, sodium hypochlorite (chlorine; NaOCl) did not impact internalization but increased the surface association of S. Typhimurium with A. castellanii. S. Typhimurium growth in culture with A. castellanii appeared to be ‘amoeba-associated’ rather than strictly intracellular, and both SSHP and NaOCl reduced the replication of S. Typhimurium in co-culture with A. castellanii. Our work demonstrates that SSHP may serve as an alternative disinfectant that may reduce the survival and proliferation of bacteria within Acanthamoeba in drinking water systems.