空氣中結核分枝桿菌採樣及單股置換放大分析方法研究

A Study on the Development of Air Sampling & Strand Displacement Amplification Analysis of Mycobacterium Tuberculosis in A Health-care Facility

本研究之目的是建立一套空氣中結核分枝桿菌的環境監測技術，並在醫院進行初步的應用。研究係參照NIOSH 0900 方法，進行空氣採樣，及利用SDA（Strand Displacement Amplification）技術偵測空氣中結核分枝桿菌（稱為 Modified NIOSH 0900 方法） ，同時與現行之 Home-made PCR 作偵測下限、與其它菌株之交叉反應（cross-reaction）的比較測試。研究結果顯示SDA 與Home-made PCR 之偵測下限在菌液中分別為 2.4x100 與 2.4x104 CFU/mL，空氣中 3.3x100 與 3.3x104 CFU/m3 ；兩者皆不與 Escherichia coli、Staphylococcus aureus、Pseudomonas aeruginosa 等院內感染前三名之菌株產生交叉反應；醫院中理論高暴露區空氣採樣之 SDA 定性陽性機率與半定量對數濃度雖略高於理論低暴露區，但均未達顯著水準。由此研究得知，以SDA 為基礎的Modified NIOSH 0900 方法之偵測下限優於文獻中 NIOSH 0900，且與 Home-made PCR 方法比較更有明顯的差異，應可應用於結核分枝桿菌的環境測試；現場測試結果顯示醫院各部門空氣中均存在不同程度的結核分枝桿菌，但是採樣分析的定性和半定量結果與理論暴露危險區域的劃分並沒有明確的相關性，宜再做進一步之研究。

The objective of the study is to establish a standard method to detect Mycobacterium tuberculosis in the air and conduct a preliminary evaluation in the hospital. NIOSH 0900 method was modified to collect air samples and analyze M. tuberculosis with SDA (Strand Displacement Amplification). Air sampling was conducted in 21 departments with presumably different risk of TB infection. As SDA analysis proceeded, the minimal detectable concentration and cross-reaction with other bacterium between the SDA and Home-made PCR was compared. The minimal detectable concentration of SDA and Homemade PCR are 2.4x100 and 2.4x104 CFU/mL in M. tuberculosis solution, 3.3 x100 and 3.3x104 CFU/m3 in airborne particles; SDA and Home-made PCR in this study do not cross react with E. coli, S. aureus or P. aeruginosa. No significant difference in qualitative and semi-quantitative analyses of M. tuberculosis exists between the predicted high- and low -risk areas in the hospital. According to the results, the minimal detectable concentration of our SDA-based method is better than the NIOSH 0900 and also superior to the Home-made PCR, making it suitable for the environmental monitoring of M. tuberculosis. Although the result indicates the presence of M. tuberculosis to various degrees in those departments of the hospital under examination, no obvious correlation in qualitative and semi-quantitative analyses was found between the predicted high- and low -risk areas. Further research is needed to address the problem.