Bacterial classification and antibiotic susceptibility testing on an integrated microfluidic platform.

Area of Science:

• Biotechnology
• Microbiology
• Analytical Chemistry

Background:

• Rising bacterial infections and antibiotic resistance necessitate faster diagnostic methods.
• Current bacterial classification (BC) and antibiotic susceptibility testing (AST) can be time-consuming.
• Digital microfluidics (DMF) offers potential for automated, high-throughput biological assays.

Purpose of the Study:

• To demonstrate the use of digital microfluidics (DMF) for automated and simultaneous bacterial classification (BC) and antibiotic susceptibility testing (AST).
• To develop and validate custom instrumentation for real-time monitoring of bacterial growth and metabolic markers.
• To assess the accuracy and versatility of the DMF system for clinical diagnostics.

Main Methods:

• Development of custom instrumentation with integrated heating and a machine-learning-enabled camera for real-time monitoring.
• Automated sample handling, mixing, incubation at 37 °C, and antibiotic dilution within the DMF system.
• Monitoring of resazurin metabolism to resorufin for bacterial growth and phenotype analysis.

Main Results:

• Simultaneous BC and AST achieved in under 18 hours.
• Accurate AST validation for uropathogenic E. coli strains against ciprofloxacin and nitrofurantoin.
• Correct identification of multiple bacterial species (E. coli, K. pneumoniae, P. mirabilis, S. aureus) and essential/category agreement for AST and breakpoint testing with reference methods.

Conclusions:

• The developed all-in-one microfluidic system demonstrates versatility and accuracy for bacterial analysis.
• This DMF approach offers a rapid and automated solution for BC and AST, crucial for combating antibiotic resistance.
• The system shows promise for point-of-care diagnostics and personalized medicine.