In previous investigations, bismuth subsalicylate (BSS) has been found to have antibacterial capabilities, although few have looked into the mechanism of action. Furthermore, other bismuth salts, such as bismuth oxychloride (BiOCl), develop throughout the gastrointestinal tract after BSS consumption, acting on enteric bacteria. The antimicrobial effect of BSS and BiOCl on Clostridium difficile, Salmonella, Shigella, Shiga toxin-producing Escherichia coli strains, and norovirus (NoV) strains were processed to better understand bismuth’s antimicrobial action in infectious diarrhea. Bacterial enteric pathogens were subjected to 35mg/ml BSS or BiOCl with or without a vehicle suspension in pure culture or human feces. Transmission electron microscopy was used to quantify and examine the BSS and BiOCl-treated samples. In addition, the reduction of infectious murine NoV (MNV), a proxy for human NoV, and Norwalk virus RNA levels were assessed using viral plaque assay and RT-qPCR, respectively, to determine the effect on NoV. In all strains, BSS and BiOCl reduced bacterial growth by 3–9 logs, with the majority resulting in populations of less than 10 cfu per ml after 24 hours. When faecal material was added, the findings were similar. At 30 minutes after treatment, microscopy images revealed bismuth on bacterial membranes and within the bacterial cells. After 24 hours of exposure, BSS and BiOCl at 8.8 mg per ml reduced MNV infectivity by 2.7 and 2.0 log, respectively. Furthermore, BSS and BiOCl reduced the number of Norwalk replicon-bearing cells by a small amount, implying that bismuth may suppress NoV in vivo. The researchers’ findings supported and expanded on previous evidence that BSS has antibacterial capabilities against a broad spectrum of diarrhea-causing microorganisms.
Link:www.tandfonline.com/doi/full/10.1080/19490976.2015.1008336
