Simple optical nanomotion method for single-bacterium viability and antibiotic response testing

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 120; no. 18
• Main Authors: Villalba, Maria I, Rossetti, Eugenia, Bonvallat, Allan, Yvanoff, Charlotte, Radonicic, Vjera, Willaert, Ronnie G, Kasas, Sandor
• Format: Journal Article
• Language: English
• Published: Washington National Academy of Sciences 02.05.2023
• Subjects: Antibiotic resistance; Antibiotics; Atomic force microscopy; Bacteria; Gram-negative bacteria; Gram-positive bacteria; Light microscopy; Microfluidics; Microorganisms; Optical microscopes; Optical microscopy; Public health
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.22212841

Antibiotic resistance is nowadays a major public health issue. Rapid antimicrobial susceptibility tests (AST) are one of the options to fight this deadly threat. Performing AST with single-cell sensitivity that is rapid, cheap, and widely accessible, is challenging. Recent studies demonstrated that monitoring bacterial nanomotion by using atomic force microscopy (AFM) upon exposure to antibiotics constitutes a rapid and highly efficient AST. Here, we present a nanomotion detection method based on optical microscopy for testing bacterial viability. This novel technique only requires a very basic microfluidic analysis chamber, and an optical microscope equipped with a camera or a mobile phone. No attachment of the microorganisms is needed, nor are specific bacterial stains or markers. This single-cell technique was successfully tested to obtain AST for motile, nonmotile, gram-positive, and gram-negative bacteria. The simplicity and efficiency of the method make it a game-changer in the field of rapid AST.