A rapid antimicrobial susceptibility test based on single-cell morphological analysis.

Area of Science:

• Microbiology
• Medical Diagnostics
• Biotechnology

Background:

• Rapid antibiotic susceptibility testing (AST) is crucial for effective treatment of bacterial infections.
• Traditional culture-based AST methods are too slow for urgent clinical situations, especially with rising antibiotic resistance.
• There is a critical need for faster diagnostic tools to guide appropriate antibiotic selection.

Purpose of the Study:

• To introduce and evaluate a novel, rapid AST method called single-cell morphological analysis (SCMA).
• To assess SCMA's accuracy and speed in determining antimicrobial susceptibility compared to gold standard methods.
• To demonstrate SCMA's utility in identifying resistance mechanisms in clinically relevant bacterial pathogens.

Main Methods:

• SCMA analyzes morphological changes in individual bacterial cells exposed to different antimicrobial agents.
• The method was validated using standard bacterial strains and 189 clinical isolates, including multidrug-resistant organisms.
• Results were compared against the Clinical and Laboratory Standards Institute (CLSI) guidelines and broth microdilution.

Main Results:

• SCMA provided antimicrobial susceptibility results in under 4 hours.
• The test demonstrated high performance with 91.5% categorical agreement compared to the gold standard.
• Discrepancy rates were low: 6.51% minor, 2.56% major, and 1.49% very major.

Conclusions:

• SCMA offers a rapid and accurate alternative for antibiotic susceptibility testing.
• The technology meets U.S. Food and Drug Administration (FDA) performance recommendations for AST devices.
• SCMA has the potential to significantly improve clinical decision-making for antibiotic therapy.