[ODP29] 6. Host defense -c. Others

[ODP-184] Germicidal effect of 222 nm-UVC on S. aureus and B. cereus adhered to fabrics

Risako Fukushi^1,2, Makiko Yamauchi¹, Sonoko Takase¹, Ryoko Kimura¹, Miwa Miura¹, Masumi Saito¹, Kouji Narita^2,3, Krisana Asano^2,4, Akio Nakane^1,4 (¹Dept. Nursing, Sch. Health Sci., Hirosaki Univ. Health Welfare, ²Dept. Microbiol. Immunol., Hirosaki Univ. Grad. Sch. Med., ³Inst. Animal Exp., Hirosaki Univ. Grad. Sch. Med., ⁴Dept. Biopolymer Health Sci., Hirosaki Univ. Grad. Sch. Med.)

Nosocomial infections can spread due to cloth products such as linens contaminated with bacteria. 254 nm-UVC light is often used for their sterilization, but it is harmful to the dermis and cornea. Recently, 222 nm-UVC is suggested to be harmless to these tissues. In this study, we investigated the germicidal effect of 222 nm-UVC light on methicillin-resistant S. aureus (MRSA) and B. cereus spores adhered to 3 types of fabrics: 100% cotton, cotton polyester (35% cotton, 65% polyester), and woven towel (100% cotton). MRSA or B. cereus spores were dropped on pieces of the fabrics and allowed to dry. Then, both sides each piece was irradiated with 222 nm-UVC at total dose of 0, 70 and 210 mJ/cm². After irradiation, the fabrics were extracted with PBS containing 0.1% Tween 20, and live bacterial number in extract was measured. For MRSA on cotton or towels, the viable cell count was undetectable after 70 mJ/cm² irradiation. The viable MRSA on cotton polyester decreased in proportion to the irradiation dose but remained even irradiation at 210 mJ/cm². For B. cereus spores, the viable cell count on cotton was undetectable after 210 mJ/cm² irradiation, but about half of the viable cells remained in cotton polyester and towels. The results suggest that the germicidal effect of 222 nm-UVC differs depending on material, weave of the fiber, and MRSA or B. cereus spores.