title: Laser light combined with a photosensitizer may eliminate methicillin-resistant strains of Staphylococcus aureus.
abstract: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital acquired infection throughout the world especially in wound and burn infections, pneumonia, septicaemia and endocarditis. We describe the effect of a HeNe laser in combination with a TBO dye on the viability of MRSA. A total of 34 isolates of S. aureus were obtained from 100 patients suffering from burns or wounds and from the nasal vestibulum of medical and nonmedical staff as carriers; eight isolates were methicillin-resistant. The isolates were exposed for 5, 10 and 15 min to a HeNe laser at a wavelength of 632.8 nm and 7.5 mW output power in the presence of 50 microg/ml toluidune blue O photosensitizer. The viable count was substantially decreased as determined by the plate count method for the three exposure times, with 100% killing with the 15-min exposure time. No significant effect was observed on MRSA isolates exposed to the laser alone. So MRSA was completely eradicated following 15 min exposure to a 632.8-nm HeNe laser in the presence of 50 microg/ml toluidune blue O photosensitizer under in vitro conditions.
authors.affiliation: Institute of Laser for Post Graduate Studies, University of Baghdad, Baghdad, Iraq.
authors.forename: Khalil I
authors.initials: KI
authors.lastname: Hajim
authors.forename: Dhuha S
authors.initials: DS
authors.lastname: Salih
authors.forename: Yasemin Z
authors.initials: YZ
authors.lastname: Rassam
mesh_terms: D058491:Bacterial Load / Q000187:drug effects / Q000528:radiation effects; D003428:Cross Infection / Q000188:drug therapy / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D066298:In Vitro Techniques; D054020:Lasers, Gas / Q000627:therapeutic use; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification / Q000528:radiation effects*; D008826:Microbial Sensitivity Tests; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology; D014048:Tolonium Chloride / Q000494:pharmacology
chemical_list: D017319:Photosensitizing Agents; D014048:Tolonium Chloride