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Updated: Feb 10, 2026

A Rapid Image-based Bacterial Virulence Assay Using Amoeba
Published on: June 27, 2018
Identification of a S. aureus virulence factor by activity-based protein profiling (ABPP)
Christian S Lentz1, Jessica R Sheldon2, Lisa A Crawford3
1Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA.
Researchers identified novel Staphylococcus aureus serine hydrolases, including FphB, crucial for infection but not growth. Inhibiting FphB reduced bacterial infectivity, offering a potential therapeutic target for Staphylococcus infections.
Area of Science:
- Microbiology
- Biochemistry
- Chemical Biology
Background:
- Serine hydrolases regulate host-pathogen interactions, but few are characterized in Staphylococcus aureus.
- Understanding these enzymes in S. aureus is critical for developing new anti-infective strategies.
Purpose of the Study:
- To identify and characterize previously uncharacterized serine hydrolases in Staphylococcus aureus.
- To investigate the role of these enzymes in bacterial pathogenesis and explore therapeutic potential.
Main Methods:
- Chemical proteomic screening to identify novel serine hydrolases.
- Biochemical assays to characterize enzyme activity and substrate specificity.
- In vitro and in vivo infection models to assess the role of FphB in pathogenesis.
Main Results:
- Ten novel S. aureus serine hydrolases, termed fluorophosphonate-binding hydrolases (FphA-J), were identified.
- FphB processes short fatty acid esters, is upregulated by host factors, and located on the bacterial cell surface and division septum.
- fphB deletion impaired S. aureus infectivity in vivo, while an FphB inhibitor reduced bacterial burden.
Conclusions:
- FphB is a key virulence factor in Staphylococcus aureus infections, dispensable for in vitro growth.
- FphB represents a promising therapeutic target for developing novel treatments against Staphylococcus infections.
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