KILLING OF METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS IN-VITRO USINGALUMINUM DISULFONATED PHTHALOCYANINE, A LIGHT-ACTIVATED ANTIMICROBIALAGENT

The aim of this study was to determine whether 16 epidemic methicillin -resistant strains of Staphylococcus aureus (EMRSA) could be killed by the light-activated antimicrobial agent aluminium disulphonated phtha locyanine (AIPcS(2)). EMRSA suspensions were irradiated with light fro m a laser diode in the presence of ArPcS2 and survivors enumerated. Al l strains were susceptible to killing, the bactericidal effect being d ependent on the AlPcS, concentration and the light dose. AlPcS, render ed the bacteria light-sensitive almost immediately and killing was una ffected by the growth phase of the organism. Scavengers of singlet oxy gen and free radicals protected the bacteria from killing. These resul ts imply that light-activated antimicrobial agents may be useful in el iminating EMRSA from wounds or carriage sites.