[en] Radiation screened 98 isolates from 3032 cfu on 56 infusion sets were studied for radiation resistance. The D₁₀ values of these screened isolates were 0.8 to 4.0 kGy and mostly ranged within 1.2 to 1.6 kGy. The microorganisms with D₁₀ ≤ 1.6 kGy were about 99.0% of the total bio-burden. All of the screened isolates were gram-positive bacteria, and 84 isolates were classified as Bacillus sp. and 14 isolates were characterized as Micrococcus sp.. One isolate with D₁₀ of 4.0 kGy (from D-6 = 24 kGy) was found outside of the infusion sets, accounting for 0.033% of the total bio-burden. The most resistant bacteria were orange colony and were classified as a Micrococcus sp. with broad shoulder