比較直接接種與增菌後移種方法對糞便中四種食品中毒病原菌的檢出效能

Comparison between Direct Inoculation and Specimen Enrichment for Detection of the Four Food Poisoning Bacteria in Stool Specimens

杜秉勳(Ping-Hsun Tu) ； 陳詩涵(Se-Han Chen) ； 趙育德(Yu-Te Chao) ； 蔡文城(Wen-cherng Tsai)

《檢驗及品保雜誌》 9卷4期 (2020/10) Pp. 175-183

https://doi.org/10.6573/JTQA.202010_9(4).02

摘要

在台灣，引起食品中毒的病原主要為細菌性，為了預防及遏止校園發生集體食品中毒，台北市衛生局自2017年起執行「除4菌、勤洗手、保食安」政策。由於校園內供膳人員與餐點的衛生安全息息相關，因此，檢測其等糞便檢體是否帶有除四菌政策的四種目標病原菌:金黃色葡萄球菌（Staphylococcus aureus）、仙人掌桿菌（Bacillus cereus, 蠟樣芽孢桿菌）、沙門氏菌（Salmonella species）以及志賀氏菌（Shigella species）將有其重要性。為了有效執行及增加這些菌的檢出率，本研究採用檢體的直接接種和增菌後移種分離培養基的檢驗流程進行500件糞便檢體的病原菌篩檢，結果指出兩種方法皆未檢出志賀氏菌，而直接接種對金黃色葡萄球菌、仙人掌桿菌與沙門氏菌的檢出率分別為0.6%（3／500）、11%（5／500）與0.4%（2／500），而增菌後移種則分別為20.6%（103／500）、5.6%（28／500）與3.8%（19／500）。比較兩種檢測流程，吾等發現增菌後移種的方式檢出金黃色葡萄球菌和沙門氏菌皆比直接接種者高，但仙人掌桿菌則相反，直接接種比增菌後移種的檢出率高。此外，將分離出的三種菌的疑似菌落分別以傳統方法與基質輔助雷射脫附游離－飛行時間質譜法（matrix-assisted laser desorption ionization time-of-flight mass spectro metry, MALDI-TOF MS）進行鑑定，結果顯示後者之鑑定準確率高達99%以上。上述的發現，可作為檢驗室檢測供膳人員糞便檢體中食品中毒病原菌的指導原則。

關鍵字

除4菌 ； 金黃色葡萄球菌 ； 仙人掌桿菌 ； 沙門氏菌 ； 志賀氏菌 ； MALDI－TOF MS

並列摘要

Food poisoning is mainly caused by bacteria. In order to prevent food poisoning in schools, the Health Bureau of Taipei City government has implemented the policy of ＂eliminating 4 bacteria, frequent hand washing, and ensuring food safety＂ since 2017. As meal serving staffs have direct contact with food, it is crucial to ensure that they do not carry the four major bacteria that cause food poisoning, including Staphylococcus aureus, Bacillus cereus, Salmonella species, and Shigella species. In this study, we determine the effectiveness of direct stool specimen inoculation and subculture after specimen enrichment in the detection of these bacteria. A total of 500 stool specimens were examined. Results showed that Shigella species were not found in these specimens and that the detection rates of direct inoculation for Staphylococcus aureus, Bacillus cereus, and Salmonella species were 0.6% (3/500), 11% (55/500), and 0.4% (2/500), and those of specimen enrichment were 20.6% (103/500), 5.6% (28/500), and 3.8% (19/500), respectively. These results indicate that Staphylococcus aureus and Salmonella species are more readily detected after specimen enrichment, whereas Bacillus cereus can be effectively detected by direct specimen inoculation. For identification of the pathogens, the MALDITOF MS (matrix-assisted laser desorption ionization time-of-flight mass spectrometry) method was found to have an accuracy rate of ＞ 99%. These findings can serve as guiding principles for detection of food poisoning bacteria by Microbiology laboratories.

並列關鍵字

Eliminating 4 bacteria ； Staphylococcus aureus ； Bacillus cereus ； Salmonella species ； Shigella species ； MALDI-TOF MS