Comparison of Membrane Filtration and Centrifugation Methods for Recovery of Legionella pneumophila Serotype 1 from Water Samples

比較濾膜法與離心法分離冷卻水塔中嗜肺性退伍軍人菌血清一型(Legionella pneumophila serotype 1)之回收率

呂旭峰(Hsu-Feng Lu) ； 孫吉珍(Chi-Chen Sun) ； 劉嘉又(Jia-You Liu) ； 陳媛孃(Yuan-Liang Chen) ； 劉啟明(Chi-Ming Liu)

《東港安泰醫護雜誌》 11卷4期 (2005/12) Pp. 167-175

https://doi.org/10.7078/TSMHMNJ.200512.0167

摘要

目的：本研究目的是比較離心法與濾膜法分離冷卻水塔中嗜肺性退伍軍人菌血清一型(Legionella pneumophila serotype 1)之分離率，並比較離心時間與轉速對分離率的影響。
材料與方法：以台中市20個冷卻水塔為研究對象，比較濾膜法與離心法分離冷卻水塔中嗜肺性退伍軍人菌血清一型之分離率。比較離心轉速（包括6600、6000、5000、4000、3000、2000, 與1000 rpm）與離心時間（10分與5分鐘）對分離率的影響。
結果：轉速6000rpm離心10分鐘則菌落數缺失去24%、轉速5000rpm離心10分鐘則菌落數缺失去38%、轉速4000rpm離心10分鐘則菌落數缺失去82%，但是轉速6600rpm離心5分鐘則菌落數缺失高達56%，代表時間對分離率的影響似乎會比轉速更重要。雖然離心法與濾膜法對細菌菌落數目的分離率有不同，濾膜法細菌菌落數目流失44%，但對水塔標準規範(The American Pathogen Association Disinfection Rules)而言並無偽陰性產生。
結論：6000g(6600rpm)離心10分鐘對於分離冷卻水塔的退伍軍人菌而言，操作既簡單又有效，相反的，濾膜法由於水塔含沙土量過高易造成不易過濾。吾等認為Log10∫ω^2dt公式同時包含了離心力與離心所需時間，其值越高分離率越高。

關鍵字

嗜肺性退伍軍人菌 ； 濾膜法 ； 離心法 ； 回收率

並列摘要

Purpose: The membrane filtration method and the centrifugation method were performed by this study to compare their recovery effectiveness and to determine an optimal speed and a proper time length of centrifugation for recovery of L. pneumophila in cooling water samples.
Methods: Water samples were collected form 20 cooling towers in Taichung City. The number of L. pneumophila in 20 water samples were isolated and compared by membrane filtration method and the centrifugation method. We also compare the recovery effectiveness by different spin-speed and time inclusive of 6600, 6000, 5000, 4000, 3000, 2000 or 1000 rpm for 10 min or 5 min for centrifugation.
Results: Twenty-four percent of colonies were lost in water samples after centrifugation at 6000 rpm for 10 min, 38% at 5000 rpm for 10 min, and 82% at 4000 rpm for 10 min but 56% at 6600 rpm for 5 min. Colonies recovered were proportionally correlated with the time length of centrifugation rather than the spin speed. There was a significant difference in the number of organisms recovered from water samples after the membrane filtration method and the centrifugation method (p＜0.001). In comparing with the centrifugation method, a colony loss of 44% was noted in the membrane filtration method but the results did not be against the American Pathogen Association Disinfection Rules on account of no false negative.
Conclusion: We suggest that Centrifugation at 6000×g (6600 rpm) for 10 min was found to be simple and efficient in the recovery of L. pneumophila serotype 1 from cooling tower water samples. In contrast, the membrane filtration method less effective due to its high content of sands and soil in most cooling tower water samples. Our findings support that the value of Log10∫ω^2dt composed of centrifugation force and time, more higher, the value is, more good the recovery rate.

並列關鍵字

Legionella pneumophila ； the membrane filtration method ； the centrifugation method ； recovery rate