- 學位論文
生物氣膠暴露對健康照護人員之致敏性研究
Study on Allergenicity of Bioaerosol Exposure to Health Care Workers
摘要
過敏性鼻炎、氣喘、異位性皮膚炎等過敏性疾病有逐年上升的趨勢，而在環境中接觸低劑量並重複暴露過敏原與過敏疾病的發生，可能存在高度的關聯性。醫院場所是細菌的匯集地，並包含多種抗藥性菌種，對於長時間在醫院工作的健康照護人員極有可能造成危害。因此本研究於中部某醫學中心之呼吸照護病房（respiratory care center, RCC），以安德森六階採樣器（Andersen six-stage sampler）進行空氣中之生物氣膠採樣。採樣後之細菌，以胰蛋白大豆瓊脂（Tryptone soy agar, TSA）培養基進行培養，並以BD Phoenix全自動微生物鑑定和藥敏性試驗分析儀（BD Phoenix™ medium ted microbial identification and susceptibility test analyzer）進行菌種鑑定以及抗藥性分析（drug-resistant analysis）。經過病房中健康照護人員之同意及IRB審查，採取血液並進行白血球與血清分離，再以非醫護人員作為對照組，偵測樣品血清中是否具有針對生物氣膠微生物的IgE專一性抗體，以及受試者的白血球是否會受到特定微生物蛋白質的刺激並誘發免疫相關基因的表現。同時，利用問卷調查收集並分析健康照護人員之工作特質與健康狀況等資料，藉以評估長期暴露在生物氣膠菌種能否誘發人體IgE免疫反應性及其可能的機制。 研究結果顯示，於呼吸照護病房所採集到之生物氣膠菌種，粒徑分佈以3.3 µm以下可呼吸性微粒為主，菌種鑑定皆為革蘭氏陽性菌，受醫護人員及訪客流動人數的影響，使會客後生物氣膠總濃度比會客前總濃度高出2~3倍，而會客前採得之生物安全等級第二級細菌（61.4%）所佔比例較多，而會客後則是生物安全等級第一級細菌（82.5%）所佔比例較多，推測是因為訪客於會客時帶入較多第一級環境菌的緣故。而在受試者血清分析中，可測得針對生物氣膠採樣所得菌株之特定蛋白質抗原的IgE免疫反應性。此外，從收集到的生物氣膠和標準細菌中純化的細菌蛋白，也具有誘發健康照護人員的周邊血液單核球之免疫反應基因的表達。綜合以上結果，顯示來自生物氣膠的細菌蛋白可能具有致敏性，從而在長期接觸生物氣膠的健康照護人員中誘導IgE反應性和免疫反應性。
並列摘要
Allergic rhinitis, asthma, atopic dermatitis and other allergic diseases have an increasing trend year by year. Exposure to low doses and repeated exposure to allergens in the environment has a great causal relationship or association with the occurrence of allergic diseases. The hospital is a collecting site of bacteria, containing multi-drug resistant strains. Health care workers （HCWs）who work in the hospital for a long time are vulnerable to the environmental bioaerosol with concentrated bacteria. Therefore, bioaerosol sampling in the respiratory care center （RCC） of a medical center in central Taiwan was conducted by using the Andersen six-stage sampler. Sampled bacteria were cultured with Tryptone soy agar （TSA） and then collected for microbial identification and antibiotic resistant analysis using the BD Phoenix®. With the consent of the HCW in the RCC and the non-medical subjects, their blood samples were collected for the isolation of serum and peripheral blood mononuclear cells (PBMCs). The serum samples and PBMCs were used for IgE reactivity and immune-responsive gene expression analysis by Western blot and quantitative real-time RT-PCR (qPCR), respectively. Meanwhile, questionnaire survey was also performed to analyze the work characteristics and health status of health care workers. Taken together, these investigations were conducted to evaluate whether long-term exposure to bioaerosol induces immunohypersensitivity and its underlying mechanism. Our results showed that the bioaerosol collected in the RCC were primarily respirable fraction with particle radius ≤ 3.3 µm. The bacterial species were all identified as Gram-positive bacteria, and the compositions of bacterial species were altered by the flow of medical staff and visitors, contributing to the 2 to 3 times increase in total concentration after the visitation as compared to that before the visitation. Moreover, most of the sampled bacteria were biosafety level 2 bacteria （61.4%） before visitation; however, after visitation, most of the sampled bacteria were biosafety level 1 bacteria （82.5%） due to visitation. This study also demonstrated that the HCWs had a higher IgE-reactivity to the bacterial proteins from collected bioaerosols as compared to non-HCWs. In addition, mRNA expression of IL-6 in PBMCs from HCWs could be induced by purified bacterial proteins from the sampled bioaerosols and standard bacteria. In conclusion, our findings reveal those bacterial proteins from bioaerosols may have allergenicity and consequently induce the IgE-reactivity and immune-responsiveness in the HCWs who have been exposed to bioaerosols for a long time.