Determination of bactericidal activity against 3HC-2-Tre-labelled Mycobacterium abscessus (Mycobacteroides abscessus) by automated fluorescence microscopy

• Published in: Journal of microbiological methods 2024-09, Vol.224, p.107002, Article 107002
• Main Authors: Mann, Lea, Siersleben, Fabienne, Lang, Markus, Richter, Adrian
• Format: Article
• Language: English
• Subjects: 2-(6-(diethylamino)benzofuran-2-yl)-3-hydroxy-4H-chromen-4-one Trehalose (3HC-2-Tre); Bactericidal activity; Fluorescence labelling; MBC; Mycobacterium abscessus; Mycobacteroides abscessus
• ISSN: 0167-7012; 1872-8359; 1872-8359
• DOI: 10.1016/j.mimet.2024.107002

The minimum bactericidal concentration (MBC) of antibiotics is an important parameter for the potency of a drug in eradicating a bacterium as well as an important measure of the potential of a drug candidate in research and development. We have established a fluorescence-based microscopy method for the determination of MBCs against the non-tuberculous mycobacterium Mycobacterium abscessus (Mycobacteroides abscessus) to simplify and accelerate the performance of MBC determination compared to counting colony forming units on agar. Bacteria are labelled with the trehalose-coupled dye 3HC-2-Tre and analysed in a 96-well plate. The results of the new method are consistent with MBC determination by plating on agar. The method was used to evaluate the bactericidality of the antibiotics rifabutin, moxifloxacin, amikacin, clarithromycin and bedaquiline. Bactericidal effects against M. abscessus were observed, which are consistent with literature data. •Determining the minimum bactericidal concentration by automated image analysis.•Characterisation of bactericidal antibiotics against M. abscessus.•Use of a fluorescent trehalose conjugate for selective labelling of mycobacteria.