Lemons Angela R, McClelland Tia L, Martin Stephen B, Lindsley William G, Green Brett J
Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV.
Field Studies Branch, Respiratory Health Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV.
J Hosp Infect. 2020 Apr 10. doi: 10.1016/j.jhin.2020.04.011.
Candida auris, often a multi-drug resistant fungal pathogen, has become an emerging threat in healthcare settings around the world. Reliable disinfection protocols specifically designed to inactivate C. auris are essential, as many chemical disinfectants commonly used in healthcare settings have been shown to have variable efficacy at inactivating C. auris.
Ultraviolet germicidal irradiation (UVGI) was investigated as a method to inactivate clinically relevant strains of C. auris.
Ten C. auris and two C. albicans isolates were exposed to ultraviolet (UV) energy to determine the UV dose required to inactivate each isolate. Using a UV reactor, each isolate (10 cells/mL) was exposed to 11 UV doses ranging from 10-150 mJ/cm and then cultured to assess cell viability.
An exponential decay model was applied to each dose-response curve to determine inactivation rate constants for each isolate, which ranged from 0.108-0.176 cm/mJ for C. auris and 0.239-0.292 cm/mJ for C. albicans. As the model of exponential decay did not accurately estimate the dose beyond 99.9% inactivation, a logistic regression model was applied to better estimate the doses required for 99.999% inactivation. Using this model, significantly greater UV energy was required to inactivate C. auris (103 to 192 mJ/cm) when compared to C. albicans (78 to 80 mJ/cm).
This study demonstrated UVGI as a feasible approach for inactivating C. auris, although variable susceptibility among isolates must be taken into account. This dose-response data is critical for recommending UVGI dosing strategies to be tested in healthcare settings.
耳念珠菌通常是一种多重耐药真菌病原体，已成为全球医疗机构中日益严重的威胁。由于医疗机构中常用的许多化学消毒剂对耳念珠菌的灭活效果不一，因此专门设计用于灭活耳念珠菌的可靠消毒方案至关重要。
研究紫外线杀菌照射（UVGI）作为灭活临床相关耳念珠菌菌株的一种方法。
将10株耳念珠菌和2株白色念珠菌分离株暴露于紫外线能量下，以确定灭活每个分离株所需的紫外线剂量。使用紫外线反应器，将每个分离株（10个细胞/毫升）暴露于11种紫外线剂量下，范围从10-150 mJ/cm²，然后进行培养以评估细胞活力。
对每个剂量反应曲线应用指数衰减模型，以确定每个分离株的灭活速率常数，耳念珠菌的灭活速率常数范围为0.108-0.176 cm/mJ，白色念珠菌的灭活速率常数范围为0.239-0.292 cm/mJ。由于指数衰减模型不能准确估计超过99.9%灭活所需的剂量，因此应用逻辑回归模型来更好地估计99.999%灭活所需的剂量。使用该模型，与白色念珠菌（78至80 mJ/cm²）相比，灭活耳念珠菌（103至192 mJ/cm²）需要显著更多的紫外线能量。
本研究证明UVGI是一种可行的灭活耳念珠菌的方法，尽管必须考虑分离株之间的易感性差异。这些剂量反应数据对于推荐在医疗机构中测试的UVGI给药策略至关重要。
