Environmental decontamination of a hospital isolation room using high-intensity narrow-spectrum light.

The performance of a new decontamination technology, referred to as 'high-intensity narrow-spectrum light environmental decontamination system' (HINS-light EDS) was evaluated by a series of three studies carried out in a hospital isolation room used to treat burns patients. The ceiling-mounted HINS-light EDS emits high-intensity 405nm light which, although bactericidal, is harmless to patients and staff thereby permitting continuous environmental disinfection throughout the day. Performance efficacy was assessed by contact agar plate sampling and enumeration of staphylococcal bacteria on environmental surfaces within the room before, during and after HINS-light EDS treatment. When the room was unoccupied, use of HINS-light EDS resulted in ∼90% reduction of surface bacterial levels and when the room was occupied by an MRSA-infected burns patient, reductions between 56% and 86% were achieved, with the highest reduction (86%) measured following an extended period of HINS-light EDS operation. In an on/off intervention study, surface bacterial levels were reduced by 62% by HINS-light EDS treatment and returned to normal contamination levels two days after the system was switched off. These reductions of staphylococci, including Staphylococcus aureus and meticillin-resistant S. aureus, by HINS-light EDS treatment were greater than the reductions achieved by normal infection control and cleaning activities alone. The findings provide strong evidence that HINS-light EDS, used as a supplementary procedure, can make a significant contribution to bacterial decontamination in clinical environments.