Effect on antibiotics on protease production by a viridans streptococcus

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.