Inactivation of gram-positive bacteria

1. A method for disinfecting air, contact surfaces or materials by inactivating one or more pathogenic Gram-positive bacteria in the air, on the contact surfaces or on the materials, said method comprising exposing the one or more pathogenic Gram-positive bacteria to visible light without using a photosensitizer, wherein the one or more pathogenic Gram-positive bacteria are selected from the group consisting of Methicillin-resistant Staphylococcus aureus (MRSA), Coagulase-Negative Staphylococcus (CONS), Streptococcus, Enterococcus , and Clostridium species, and wherein a portion of the visible light that inactivates the one or more pathogenic Gram-positive bacteria consists of wavelengths in the range 400-420 nm, and wherein the method is performed outside of the human body and the contact surfaces or the materials are non-living.

2. The method according to claim 1 wherein the visible light that inactivates has a wavelength of 405 nm.

3. A system for disinfecting air, contact surfaces or materials by inactivating one or more pathogenic Gram-positive bacteria in the air, on the contact surfaces or on the materials, the system comprising means for exposing said bacteria to visible light without using a photosensitizer, wherein the one or more pathogenic Gram-positive bacteria are selected from the group consisting of Methicillin-resistant Staphylococcus aureus (MRSA), Coagulase-Negative Staphylococcus (CONS), Streptococcus, Enterococcus and Clostridium species, and wherein a portion of the visible light that inactivates the one or more pathogenic Gram-positive bacteria consists of wavelengths in the range 400-420 nm, and wherein the system is for use outside of the human body and the contact surfaces or the materials are non-living.

4. The system according to claim 3 wherein the portion of the visible light that inactivates has a wavelength of 405 nm.