- 期刊
評估常見氣單胞菌（Aeromonas）菌種的鑑定方法
Evaluation of Methods for the Identification of Common Aeromonas Species
摘要
Aeromonas（氣單胞菌）菌種為常見水域環境棲息菌，可引起人類伺機性感染。為了更正確地鑑定氣單胞菌菌種，本研究選擇其中的兩個菌種［包括12株A. hydrophila（嗜水性氣單胞菌）與5株A. veronii（維隆氣單胞菌）］接種三糖鐵瓊脂（triple sugar iron agar, TSIA）、離胺酸脫酸酶培養基（lysine decarboxylase medium, LYS）及其它10種傳統生化／生理鑑定培養基，然後均於35℃培養20～72小時，藉由不同培養時間的判讀，以了解培養時間對不同Aeromonas菌種在各種傳統生化試驗培養基的反應變化。結果指出兩種菌接種於TSIA，在20～28小時判讀斜面時約有40%的面積呈黃色反應（代表可利用乳糖及／或蔗糖），隨著培養時間的增加，呈黃色面積漸漸縮小範圍直至完全變成紅色（培養72小時），也就是反應會由陽性轉變為陰性。然而，TSIA基底則呈黃色，並不隨著培養時間發生變化。另外，將兩種菌的測試菌株接種LYS，培養時間由24小時至48小時，陽性反應由50%（8/16）增加至100%。至於其它10種測試的傳統生化試驗培養基之反應並不隨著培養時間的延長而發生變化。本研究亦評估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）鑑定氣單胞菌屬及菌種層次的正確性，結果指出MALDI-TOF MS 能正確鑑定至屬（genus）層次的正確性為100%（17/17），而至種（species）層次為35.3%（6/17），且所鑑定的菌種名稱未能進一步區分至subspecies（亞種）或biovariants（生物變種）。本研究的結果提供鑑定Aeromonas species有用的訊息，可做為食品廠品管室及臨床檢驗室的參考。
並列摘要
Aeromonas species are common inhabitants in water and can cause opportunistic infections in humans. In this study, two species of Aeromonas, including 12 strains of Aeromonas hydrophila and 5 strains of A. veronii were examined to determine appropriate methods for their identification. The bacteria were inoculated on triple sugar iron agar (TSIA) and in lysine decarboxylase medium (LYS) and 10 other traditional biochemical identification media. The inoculated cultures were then incubated at 35°C for 20~72 hours. Results showed that about 40% of the slant area in TSIA was yellow indicating lactose and/or sucrose utilization) during the first 20~28 hours of incubation, but this yellow area was gradually reduced over time and completely converted to red after 72 hours of culture, indicating a change from positive to negative response. However, the butt area of TSIA remained yellow during the entire 72 hours of incubation. In LYS media, positive response was increased from 50% (8/16) in 24 hours to 100% in 48 hours. For the other 10 traditional biochemical test media, the response did not change over time during the entire 72 hours of incubation. The performance of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) in the identification of Aeromonas was also assessed. Results indicated that MALDI-TOF MS had an accuracy rate of 100% (17/17) at the genus level. At the species level, MALDI-TOF MS had an accuracy rate of only 35.3% (6/17) and could not distinguish subspecies or biovariants. Results of this study provide useful information for the identification of Aeromonas species in the quality control laboratory of food companies and clinical laboratories.