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Effect on antibiotics on protease production by a viridans streptococcus
Abstract:
A viridans streptococcus (Streptococcus MG intermedius 974) isolated from a confirmed case of subacute bacterial endocarditis was studied for the production of extracellular proteases during exponential growth and after penicillin (0.10 mug/ml) and/or streptomycin (20 mug/ml) treatment. Exponentially growing cultures produced a variety of extracellular proteases, as determined by the elution profiles of active proteins from Sephadex G-100 and Sepharose 4B columns. Examination of supernatant fluids from cultures of S. MG intermedius treated with penicillin or streptomycin for 12 h indicated a reduction of at least 50% in the number of different proteolytic species produced. However, some of the proteases produced by the cultures during penicillin or streptomycin treatment had significantly higher specific activities when compared with proteases produced by exponentially growing cells. The combination of penicillin and streptomycin further reduced both the number and the specific activities of the extracellular proteases on a cell dry weight basis.
Insights
This study investigated extracellular protease production by viridans streptococcus during antibiotic treatment. Penicillin and streptomycin reduced protease diversity and activity, with combined use showing the greatest impact.
Area of Science:
- Microbiology
- Biochemistry
Background:
- Subacute bacterial endocarditis is a serious infection often caused by viridans streptococci.
- Extracellular proteases produced by bacteria can contribute to virulence and tissue damage.
Purpose of the Study:
- To investigate the effect of penicillin and streptomycin on extracellular protease production by viridans streptococcus (Streptococcus MG intermedius 974).
Main Methods:
- Streptococcus MG intermedius was cultured and treated with penicillin and/or streptomycin.
- Extracellular proteases were analyzed using Sephadex G-100 and Sepharose 4B chromatography.
- Specific activities of proteases were quantified.
Main Results:
- Exponentially growing cultures produced diverse extracellular proteases.
- Penicillin or streptomycin treatment reduced the number of proteolytic species by at least 50%.
- Some proteases exhibited higher specific activity after antibiotic treatment; combined antibiotics further reduced protease number and activity.
Conclusions:
- Antibiotic treatment, particularly in combination, significantly alters extracellular protease production in viridans streptococci.
- Understanding these changes may offer insights into therapeutic strategies for bacterial endocarditis.