Inactivation of Bacillales and Clostridiales spores is of interest, since some cause food spoilage and human diseases. A recent publication (mSphere 3: e00597‐1, 2018) reported that glycerol monolaurate (GML) in a non‐aqueous gel (GMLg) effectively killed spores of Bacillus subtilis, Bacillus cereus and Clostridioides difficile, and Bacillus anthracis spores to a lesser extent. We now show that (i) the B. subtilis spores prepared as in the prior work were impure; (ii) if spore viability was measured by diluting spores 1/10 in GMLg, serially diluting incubations 10‐fold and spotting aliquots on recovery plates, there was no colony formation from the 1/10 to 1/1000 dilutions due to GMLg carryover, although thorough ethanol washes of incubated spores eliminated this problem and (iii) GMLg did not kill highly purified spores of B. subtilis, B. cereus, Bacillus megaterium and C. difficile in 3–20 h in the conditions used in the recent publication. GMLg also gave no killing of crude B. subtilis spores prepared as in the recent publication in 5 h but gave ~1·5 log killing at 24 h. Thus, GMLg does not appear to be an effective sporicide, although the gel likely inhibits spore germination and could kill spores somewhat upon long incubations.

中文翻译：

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单月桂酸甘油酯在非水凝胶中缺乏对纯化的芽孢杆菌和梭菌属的休眠孢子的有效杀灭

芽孢杆菌和梭菌孢子的灭活是有意义的，因为有些会导致食物变质和人类疾病。最近的一份出版物 (mSphere 3: e00597-1, 2018) 报道，单月桂酸甘油酯 (GML) 在非水凝胶 (GMLg) 中有效杀死枯草芽孢杆菌、蜡状芽孢杆菌和艰难梭菌的孢子，以及炭疽芽孢杆菌孢子的程度较低. 我们现在表明（i）如先前工作中制备的枯草芽孢杆菌孢子是不纯的；(ii) 如果通过在 GMLg 中稀释 1/10 的孢子，连续稀释 10 倍并在回收板上点样等分试样来测量孢子活力，则由于 GMLg 残留，从 1/10 到 1/1000 稀释不会形成菌落，尽管对培养的孢子进行彻底的乙醇洗涤消除了这个问题，并且 (iii) GMLg 不能杀死枯草芽孢杆菌、蜡状芽孢杆菌的高度纯化的孢子，在最近出版物中使用的条件下，巨大芽孢杆菌和艰难梭菌在 3-20 小时内。GMLg 也没有在 5 小时内杀死如最近出版物中制备的粗枯草芽孢杆菌孢子，但在 24 小时内杀死了 ~1·5 log。因此，GMLg 似乎不是一种有效的孢子杀灭剂，尽管凝胶可能会抑制孢子萌发并且在长时间孵育后可能会在一定程度上杀死孢子。