Engineered colorimetric detection of Staphylococcus aureus extracellular proteases

Area of Science:

• Microbiology and Biotechnology
• Assay Development
• Diagnostic Tools

Background:

• Staphylococcus aureus (S. aureus) is a significant pathogen.
• Accurate detection of S. aureus is crucial for clinical and public health.
• Existing methods for detecting S. aureus protease activity can be improved for sensitivity and specificity.

Purpose of the Study:

• To engineer a feasible, sensitive, and specific colorimetric assay for S. aureus extracellular protease production.
• To develop a tailored agar-based readout platform for enhanced proteolysis detection.
• To validate the assay's specificity and sensitivity for S. aureus detection in various sample types.

Main Methods:

• Evaluated S. aureus protease production in different culture media, optimizing for brain heart infusion (BHI) broth.
• Developed novel agar-based platforms using skim milk as a substrate for protease detection.
• Implemented colorimetric visualization techniques, including Bromocresol Purple and bromothymol blue dyes, for readout.

Main Results:

• Optimized conditions identified maximum proteolytic activity in BHI broth after 24 hours at 37°C.
• The developed agar platform showed clear proteolytic zones, with colorimetric visualization yielding a positive readout within 15 minutes.
• Achieved a low limit of detection for S. aureus at 10^2 CFU mL^-1 using the colorimetric assay, with specificity demonstrated against Escherichia coli.

Conclusions:

• The engineered colorimetric assay provides a sensitive, specific, and feasible method for detecting S. aureus protease production.
• The tailored agar-based readout platform offers a rapid and visual detection system.
• This assay holds significant potential for S. aureus detection in various biomedical applications.