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Immunoglobulin A1 protease activity in Gemella haemolysans
1Department of Medical Microbiology and Immunology, University of Aarhus, DK-8000 Aarhus C, Denmark.
Journal of Clinical Microbiology
|July 6, 2000
Summary
Immunoglobulin A1 (IgA1) protease activity was found exclusively in Gemella haemolysans among tested Gemella species. This finding aids in differentiating bacterial species within this genus.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Enzymology
Background:
- Immunoglobulin A1 (IgA1) proteases are virulence factors produced by certain bacteria.
- The genus Gemella and related taxa are part of the normal human microbiota but can be associated with infections.
Purpose of the Study:
- To investigate the presence and characteristics of IgA1 protease activity in Gemella species and related bacteria.
- To assess the utility of IgA1 protease activity for bacterial species identification.
Main Methods:
- Screening of 22 Gemella strains and 4 related species for IgA1 protease activity.
- Phenotypic characterization of the enzyme and its cleavage site.
Main Results:
- All nine isolates of Gemella haemolysans exhibited IgA1 protease activity.
- No IgA1 protease activity was detected in other Gemella species or related taxa tested.
- The IgA1 protease from G. haemolysans was identified as a metallo-type enzyme cleaving the Pro(227)-Thr(228) bond.
Conclusions:
- IgA1 protease activity is a specific marker for Gemella haemolysans.
- This enzymatic activity can be a valuable tool for differentiating bacterial species within the Gemella genus and related bacteria.