Service de Bactériologie, Université de Nantes, CHU Nantes, CRCINA U1232, F-44000, Nantes, France.
Department of Biomedicine, University Hospital, Basel, Switzerland.
Anaerobe. 2020 Dec;66:102282. doi: 10.1016/j.anaerobe.2020.102282. Epub 2020 Oct 2.
Detection of anaerobe bacteria by culture methods requires appropriate media, special growth conditions, additional detection techniques and it typically takes several days. Therefore, anaerobes are often missed in patient specimens under routine culture conditions. Microcalorimetry may provide a simple and accurate real-time method for faster and better detection of anaerobes. An isothermal calorimeter which detect minimal changes of temperature over time was used for the calorimetric experiments. In order to find optimal growth conditions, seven reference or clinical strains of medical relevant anaerobe bacteria were tested under different circumstances. First, the strains were tested with different growth media. After determining the optimal medium for each strain, the gas phase was modified by adding 3 mL or 4 mL medium, to evaluate growth under conditions with less oxygen. Cooked Meat Medium was best supporting growth of the tested strains, including Cutibacterium acnes, Fusobacterium nucleatum, Finegoldia magna, Parvimonas micra, Bacteroides fragilis and Actinomyces odontolyticus, followed by thioglycolate. The best medium to detect Clostridioides difficile was H-Medium. All tested strains showed better growth in 4 mL medium than in 3 mL. The detection time ranged between 10 and 72 h. Our results demonstrated that the sensitivity and the detection time of anaerobe bacteria can be improved by isothermal calorimetry with optimization of growth conditions. Therefore, calorimetric detection, a practical, quick and easy-to-do method, has the potential to replace current microbiological methods.
通过培养方法检测厌氧菌需要适当的培养基、特殊的生长条件、额外的检测技术，并且通常需要数天时间。因此，在常规培养条件下，患者标本中的厌氧菌经常被遗漏。微热量计可能提供一种简单而准确的实时方法，用于更快、更好地检测厌氧菌。本研究使用一种检测随时间变化的最小温度变化的等温热量计进行了热量计实验。为了找到最佳的生长条件，我们在不同情况下测试了七种参考或临床相关的医学厌氧菌菌株。首先，我们用不同的生长培养基测试了这些菌株。在确定每种菌株的最佳培养基后，通过添加 3 或 4 毫升培养基来改变气相，以评估在氧气较少的条件下的生长情况。熟肉培养基最有利于测试菌株的生长，包括痤疮丙酸杆菌、核梭杆菌、大消化链球菌、小韦荣球菌、脆弱拟杆菌和龋齿放线菌，其次是硫代乙醇酸盐。检测艰难梭菌的最佳培养基是 H 培养基。所有测试菌株在 4 毫升培养基中的生长情况均优于 3 毫升。检测时间在 10 至 72 小时之间。我们的结果表明，通过优化生长条件，等温热量计可以提高厌氧菌的灵敏度和检测时间。因此，热量计检测作为一种实用、快速、易于操作的方法，有可能取代当前的微生物学方法。
