Characterization of medical relevant anaerobic microorganisms by isothermal microcalorimetry. (December 2020)

• Record Type: Journal Article
• Authors: Corvec, Stéphane; Seiler, Eva; Wang, Lei; Moreno, Mercedes Gonzalez; Trampuz, Andrej
• Is Part Of: Anaerobe. Volume 66(2020)
• Publication Date: 2020-12
• Subjects: Anaerobes -- Detection -- Calorimetry; Anaerobic infections -- Periodicals; Anaerobic bacteria -- Periodicals; Bacterial diseases -- Periodicals; Computer network resources; Anaerobic protozoa -- Periodicals; 579.3
• DOI: 10.1016/j.anaerobe.2020.102282
• Languages: English
• ISSNs: 1075-9964

Abstract

Abstract: 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. Highlights: Detection of anaerobes requires appropriate media and takes typically several days. Microcalorimetry (detecting the heat produced during the bacterial growth) may provide a simple and accurate real-time method for faster and better detection of anaerobes. Cooked Meat Medium was the best medium to detect anaerobes except for Clostridioides difficile (H-Medium). The detection time was reduced with less oxygen in the ampoule introduced in the microcalorimeter.