Space Disinfection Using TiO2 Photocatalyst Reduces the Incidence of Febrile Neutropenia in Cancer Patients

Background/Purpose

Febrile neutropenia (FN) is life-threatening condition, and airborne microorganisms have been identified as one of the potential transmission routes. Therefore, air disinfection using laminar air flow (LAF) unit with high-efficiency particulate air (HEPA) filter is recommended to prevent infection in patients undergoing intense chemotherapy. However, HEPA filters are expensive and not available in sufficient numbers. Recently, TiO2-photocatalyzed reactions have garnered attention because of their strong oxidative degradation ability against various bacteria, fungi, and viruses. In this study, we investigated the effect of spatial sterilization using a photocatalyst device, which is inexpensive and easy to install and maintain, on the incidence of FN and the causative microorganisms in patients undergoing cancer treatment.

Methods

The space disinfection device which equipped a mechanism that irradiates photocatalytic platinum-added titanium dioxide with 405 nm wavelength LED (LED-TiO2 device) is exhibits a strong oxidative degradation effect. In a previous study, the LED-TiO2 device inactivated aerosolized SARS-Cov-2 viruses in a 120-L acrylic box in 20 minutes. LED-TiO2 device was installed per 21.5-35 m³ in hospital rooms to investigate changes in the incidence of FN and the number of airborne microorganisms.

Results

Airborne microorganisms in the hospital rooms matched those responsible for nosocomial infections. The incidence of nosocomial infections showed a decreasing trend in the After group compared with that in the before group, but the difference was not significant (Figure 1c; 13/32 versus 5/23, P = 0.160). However, the incidence of FN was significantly reduced after installation of the LED-TiO2 device (9/13 vs 2/12, P=0.015). Among the FN cases, pneumonia occurred in 4/13 patients before group and 0/12 patients after group (P = 0.096). In addition, When G-CSF was not administered due to AML/MDS or induction of remission therapy, there was a significant decrease between the Before and After groups (7/8 versus 2/8, P = 0.041). The LED-TiO2 device decreased the number of airborne microorganisms in patient-free rooms by approximately 75% after 2 hours (P<0.001). When patient was in the room, the number of airborne microorganisms increased with medical procedure. However, after 20 minutes after procedure, the number of airborne microorganisms was approximately 50% lower than without the device room (p=0.019).

Conclusions

The LED-TiO2 device successfully achieved spatial disinfection in hospital rooms, and reduced the incidence of FN. Spatial disinfection using photocatalysts is considered an effective new infection prevention measure in patients with severe neutropenia undergoing cancer treatment.

Hatta:Kyowa Hakko Kirin CO. LTD: Honoraria; Chugai Pharmaceutical Co., LTD.: Honoraria; Nihon Servier Co., LTD: Honoraria; Bristol-Myers Squibb Co: Honoraria; Phizer Japan Inc: Honoraria.