Studies of the effectiveness of compact size ultraviolet (UV) air disinfection system against airborne bacteria were conducted in patient rooms with 3.15m×5.0m, 3.8m ceiling. The air disinfection systems were activated 24 hrs per one day. Four points of air sampling of 8 ft3 in volume were performed every one week for 3 months. No limitations were applied to incoming/outgoing of patients and medical staffs. Mean colony count of airborne organisms of air samples with UV air disinfection systems off was 4.0±1.9 CFU/ft3, and reduced to 1.4±1.0 CFU/ft3 after UV air disinfection systems on. Rates of 65% reduction of microorganisms were observed under the condition with air disinfection systems activated (p<0.01). Under existence of patients with infected wound, mean colony count of organisms was still increased, from 2 to 10 times higher, after the treatment of wounds.
Used linen may be soiled with large numbers of pathogenic organisms. Although these organisms are unlikely to cause infection in patients and health care workers (HCWs) handling the linen, HCWs should follow the appropriate procedure of sorting, transportation and disinfection. The results of questionnaires about utilization and laundering practices (30 Private Medical University Hospital in Japans, 1994) by the author showed that most hospitals prefer chemical disinfection to heat disinfection. However, there exist some problems related to chemical disinfection, especially exposure of glutaraldehyde to HCWs. In 1996, another investigation was conducted and also pointed out the occupational hazard of handling chemical disinfectants. In Japan, authorized method for disinfection of linen are chemical disinfection and heat disinfection. Many outside commercial laundry services are used for cleaning hospital linen and they generally use various forms of chemical disinfection for cleaning. The present system for the handling of hospital linen has serious problems, particularly the unnecessary use of chemical disinfectants for linen, exposure of HCWs to chemical agents and increase of environmental pollution. Used linen have to be handled according to Standard Precautions. That suggests that all blood and body fluids, excretion or secretion are to be regarded as infected. Linen should be divided into three categorizes: 1) contaminated, 2) used, 3) heat-iable. “Contaminated” linen should be defined as linens soiled by blood, body fluids, excretion or secretion and linens from infected patients. These linen should be first placed into a water-soluble bag. Used linen is defined as items soiled by the use of non-infected patients, excluding blood stains, secretion or excretion. This report discusses the need for Japanese hospitals to protect HCWs and commercial laundry workers from the exposure to pathogenic organisms or chemical agents, by introducing the correct definition of contamination, appropriate procedures for hospital linens and providing appropriate equipment in hospitals.