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Immunochemical analysis of the extracellular slime substance of Staphylococcus epidermidis
P Kotilainen1, J Mäki, P Oksman
1Department of Medical Microbiology, University of Turku, Finland.
Abstract:
To analyze immunochemically the extracellular slime substance of Staphylococcus epidermidis, rabbits were repeatedly immunized with the crude slime extract isolated from an adherent, slime-producing clinical Staphylococcus epidermidis strain. Immunoelectron microscopy demonstrated that the target antigens of the resulting antibodies were located in the extracellular slime-like layer of bacterial cells. When these target antigens were characterized by immunoblotting, a variety of antigens were detected, including many with molecular masses higher than 80 kilodaltons and also a predominant one with a molecular mass of 30 kilodaltons. No characteristic differences were observed between the tube adherence test positive and negative Staphylococcus epidermidis isolates. Although there was variation in the number and intensity of high molecular mass antigens, such variations did not correlate with the tube adherence test. Of the 110 Staphylococcus epidermidis isolates studied, 106 (96%) expressed the 30-kilodalton antigen. This component was found in no other Staphylococcus spp. examined in the study. The bacterial component was not only easily detached from bacterial cells but also water-soluble, characteristics implicating a slime-like nature. Further studies are needed to definitively establish the origin and nature of the 30-kilodalton Staphylococcus epidermidis-specific component, and determine its potential benefit as a diagnostic tool.
Insights
Researchers identified a specific 30-kilodalton antigen in Staphylococcus epidermidis slime. This water-soluble component is present in most isolates and could be a valuable diagnostic tool.
Area of Science:
- Microbiology
- Immunology
- Biochemistry
Background:
- Staphylococcus epidermidis is a common cause of infections, often associated with medical devices.
- The extracellular slime substance plays a role in bacterial adhesion and biofilm formation.
- Immunochemical analysis is crucial for understanding the composition of bacterial virulence factors.
Purpose of the Study:
- To immunochemically characterize the extracellular slime substance of Staphylococcus epidermidis.
- To identify specific antigens within the slime layer.
- To evaluate the diagnostic potential of identified components.
Main Methods:
- Rabbits were immunized with crude slime extract from Staphylococcus epidermidis.
- Immunoelectron microscopy was used to localize target antigens.
- Immunoblotting was employed to characterize antigen molecular masses.
- Adherence tests were performed on bacterial isolates.
Main Results:
- Antibodies recognized antigens in the extracellular slime layer.
- Immunoblotting revealed antigens with molecular masses >80 kDa and a predominant 30 kDa antigen.
- The 30 kDa antigen was expressed by 96% of Staphylococcus epidermidis isolates.
- This 30 kDa component was absent in other Staphylococcus species and was water-soluble.
Conclusions:
- A specific 30 kDa antigen is highly prevalent in Staphylococcus epidermidis.
- This antigen's characteristics suggest a slime-like nature.
- The 30 kDa antigen shows potential as a diagnostic marker for Staphylococcus epidermidis infections.