@article{mbs:/content/journal/jmm/10.1099/00222615-44-4-245, author = "Millson, C. E. and Wilson, M. and Macrobert, A. J. and Bedwell, J. and Bown, S. G.", title = "The killing of Helicobacter pylori by low-power laser light in the presence of a photosensitiser", journal= "Journal of Medical Microbiology", year = "1996", volume = "44", number = "4", pages = "245-252", doi = "https://doi.org/10.1099/00222615-44-4-245", url = "https://www.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-44-4-245", publisher = "Microbiology Society", issn = "1473-5644", type = "Journal Article", abstract = " Helicobacter pylori is associated with various gastrointestinal disorders. Lethal photosensitisation was investigated as a possible technique for killing H. pylori which might offer a better alternative to antibiotics. The susceptibility of H. pylori to lethal photosensitisation was determined by mixing suspensions of H. pylori with various photosensitisers and plating out on blood agar before irradiation with low-power laser light. Five sensitisers were studied further by mixing them with H. pylori in a tissue-culture plate and counting survivors after irradiation as a function of laser exposure time, dye concentration and pre-irradiation time. Crystal violet and thionin were ineffective as sensitisers, but zones of inhibition appeared with methylene blue (MB), protoporphyrin IX (PPIX), haematoporphyrin derivative (HPD), toluidine blue O (TBO) and disulphonated aluminium phthalocyanine (S2). Laser light or sensitiser alone did not affect bacterial viability. S2 (100 μg/ml) with a laser light energy density of 16 J/cm2, HPD (100 μ/ml) with 160 J/cm2, MB (100 μg/ml) with 21 J/cm2, PPIX (150 μg/ml) with 320 J/cm2 and TBO (50 μg/ml) with 160 J/cm2 all reduced bacterial viability by > 99%. The killing of sensitised H. pylori by laser light offers a new approach to the treatment of localised infections when all colonised areas are accessible to light.", }