評估基質輔助雷射脫附游離飛行質譜儀（MALDI-TOF MS）對退伍軍人菌的鑑定效能

Evaluation of the Suitability of Implementing Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for the Identification of Legionellaceae Commonly Encountered in Aquatic Environment

黃品瑜(Pin-Yu Huang) ； 陳羿樺(I-Hua Chen) ； 蔡文城(Wen-cherng Tsai)

《檢驗及品保雜誌》 6卷1期 (2017/03) Pp. 51-62

https://doi.org/10.6573/JTQA.201703_6(1).07

摘要

退伍軍人症(Legionnaires' disease)係由吸入自然水域環境中退伍軍人菌(Legionellaceae)而引起的疾病，常在冷氣機的冷卻水或蓮蓬頭中發現。退伍軍人菌傳統的鑑定方法甚為繁瑣，費時費力，因此其快速簡易鑑定不僅有助於早日處理汙染水體，也可節省檢驗室的人力物力。最近幾年來，基質輔助雷射脫附游離飛行質譜儀(matrix-assisted laser desorption ionization-time of flight mass spectrometry, MALDI-TOF MS)常被用為臨床微生物的鑑定工具，其是否適合環境分離退伍軍人菌的鑑定需要加以評估。本研究是利用MALDI-TOF MS (Bruker Biotyper version 2.0)對傳統方法確認的Legionella pneumophila（嗜肺退伍軍人菌）及Legionella spp.（退伍軍人菌菌種）的水域環境檢體分離株進行鑑定，發現對L. pneumophila的鑑定正確性為91.6%(219/239)，其中錯誤鑑定計有9株(3.8%)，未能鑑定者(無圖譜，no peaks)11株(4.6%)，而對Legionella spp.的正確性則為92.7%(241/260)，其中錯誤鑑定13株(5%)，未能鑑定者11株(4.2%)。進一步發現水域環境中Legionella spp.最常見的菌種為L. anisa，佔91.6%(219/239)。根據上述的發現，吾等認為MALDI-TOF MS適合水域環境中退伍軍人菌的快速鑑定，但如再操作馬尿酸水解（hippurate hydrolysis）試驗將更可提高鑑定的正確性。

關鍵字

基質輔助雷射脫附游離飛行質譜儀 ； 嗜肺退伍軍人菌 ； 退伍軍人菌菌種 ； 馬尿酸水解試驗

並列摘要

Legionnaires' disease is caused by Legionellaceae acquired through the inhalation of droplets from natural aquatic environments. These etiologic agents are commonly encountered in water from cooling towers or showers. The conventional detection method used for detecting Legionella species is considered to be tedious, time-consuming, and labor-intensive. Therefore, a rapid identification method for these species would not only allow for earlier treatment of contaminated bodies of water but would also save on costs and labor in terms of laboratory work. Recently, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been implemented as a microbial identification tool in most of the larger clinical microbiology laboratories. However, the suitability of MALDI-TOF MS for identifying Legionella species still needed to be evaluated. This study used the Bruker Biotyper (version 2.0) to verify Legionella pneumophila and other Legionella spp. that ha d been identified by the conventional method. The results indicated that the rate of accuracy for the identification of L. pneumophila was 91.6% (219/239). There were 9 strains that were incorrectly identified (3.8%) and 11 strains (4.6%) that the test was unable to identify (no peaks on profile). As for the Legionella spp. other than L. pneumophila, the rate of accuracy in terms of identification was 92.7% (241/260). There were 13 strains (5%) that were incorrectly identified and 11 strains (4.2%) that the test was unable to identify. Through further studies of the Legionella spp., we found that the most common Legionella species is L. anisa (91.3%, 220/241). Based on the above findings, we consider the use of MALDI-TOF MS to be appropriate for the rapid identification of Legionellaceae. Furthermore, the accuracy rate of the identification will be increased if the hippurate hydrolysis test is performed simultaneously.

並列關鍵字

MALDI-TOF MS ； Legionellaceae ； hippurate hydrolysis test