Lethal photosensitisation of Staphylococcus aureus.
The purpose of this study was to determine whether toluidine blue O (TBO) could sensitise Staphylococcus aureus to killing by light from a low-power helium/neon (HeNe) laser. Suspensions of the organism were irradiated with light from a HeNe laser in the presence and absence of TBO and the survivors enumerated. A 95% reduction (9 x 10(7) cfu) in the viable count was achieved following irradiation with 0.88 J of HeNe laser light in the presence of 12.5 micrograms/ml TBO whereas no significant reductions in viability were found when suspensions were exposed to this dose of laser light in the absence of TBO. With higher doses (3.5 J) of laser light statistically significant kills (3 x 10(7) cfu) were obtained in the absence of TBO implying the presence of an endogenous photosensitiser in the organism.
Wilson
M
M
Department of Microbiology, Institute of Dental Surgery, University of London, Great Britain.
Pratten
J
J
D015169:Colony Count, Microbial; D007834:Lasers; D008027:Light; D017319:Photosensitizing Agents / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development; D013997:Time Factors; D014048:Tolonium Chloride / Q000494:pharmacology*
D017319:Photosensitizing Agents; D014048:Tolonium Chloride