A high-throughput and low-waste viability assay for microbes

Area of Science:

• Microbiology
• Cell Biology
• Biotechnology

Background:

• Accurate cell viability assessment is crucial in microbiology.
• The standard colony-forming unit (CFU) assay is time-intensive and resource-demanding.
• Existing methods limit large-scale viability studies.

Purpose of the Study:

• Introduce the geometric viability assay (GVA) as a novel method for cell viability measurement.
• Demonstrate GVA's efficiency in terms of time and resource consumption compared to CFU.
• Validate GVA's applicability across diverse microbial species and experimental setups.

Main Methods:

• GVA quantifies viable cells based on the growth distribution of embedded colonies within a pipette tip.
• The method was tested with various bacteria (e.g., Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis) and fungi (Saccharomyces cerevisiae).
• GVA was evaluated for its compatibility with planktonic cells, biofilms, and challenging experimental conditions.

Main Results:

• GVA accurately replicates CFU measurements across six orders of magnitude.
• The assay reduces time and consumables by over 10-fold compared to traditional CFU methods.
• GVA demonstrated broad compatibility with different microbial types, including slow-growing cells.

Conclusions:

• GVA provides a simplified, cost-effective, and rapid alternative to CFU assays for determining microbial viability.
• The assay streamlines complex microbiological experiments like checkerboard assays and drug screens.
• GVA has the potential to replace existing viability assays and facilitate measurements at unprecedented scales.