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In Vitro Assay for Quantifying Clumping of Staphylococcus aureus
Heidi A Crosby1,2, Jakub M Kwiecinski1, Alexander R Horswill3,4
1Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA.
Methods in Molecular Biology (Clifton, N.J.)
|July 15, 2021
Summary
This study introduces a quantitative clumping assay to measure Staphylococcus aureus
Area of Science:
- Microbiology
- Bacterial Adhesion
- Protein Interactions
Background:
- Staphylococcus aureus forms clumps when interacting with fibrinogen in plasma.
- A slide agglutination test using rabbit plasma is a clinical method to differentiate S. aureus from other staphylococci.
Purpose of the Study:
- To develop a quantitative method for studying Staphylococcus aureus clumping.
- To investigate the role of cell wall-anchored adhesins in bacterial clumping.
Main Methods:
- A quantitative clumping assay was developed using S. aureus cells mixed with plasma or purified fibrinogen.
- Clump sedimentation was monitored by measuring optical density at 600 nm over time.
- Changes in optical density were compared to initial turbidity to quantify clumping.
Main Results:
- The assay effectively quantifies the clumping of S. aureus cells.
- The method allows for the measurement of fibrinogen-mediated aggregation.
Conclusions:
- This quantitative clumping assay provides a simple method to study S. aureus interactions with fibrinogen.
- The assay can be utilized to investigate the regulation and expression of cell wall-anchored adhesins involved in clumping.
