Bacteriocin of a group A streptococcus: partial purification and properties

Area of Science:

• Microbiology
• Bacteriology
• Biochemistry

Background:

• Certain strains of group A streptococci exhibit bacteriocin-like inhibitory activity.
• Bacteriocin production was observed during growth on solid media but not in broth cultures.
• Potential inactivation by streptococcal proteinase may explain the lack of recovery in liquid cultures.

Purpose of the Study:

• To demonstrate bacteriocin production by group A streptococci.
• To partially purify and characterize the bacteriocin, named streptocin A.
• To determine the spectrum of activity and stability of streptocin A.

Main Methods:

• Cultivation of Streptococcus pyogenes on solid nutrient media.
• Partial purification using chemical precipitation and carboxymethyl-cellulose chromatography.
• Testing inhibitory activity against Gram-positive and Gram-negative bacteria.
• Assessing stability against proteolytic enzymes, alkali, and heat in mild acids.

Main Results:

• Bacteriocin-like inhibition was produced by group A streptococci on solid media.
• Streptocin A, from Streptococcus pyogenes FF-22, was partially purified.
• Streptocin A inhibited Gram-positive bacteria but not Gram-negative bacteria.
• The bacteriocin was inactivated by proteolytic enzymes and alkali but stable in mild acids.

Conclusions:

• Group A streptococci can produce active bacteriocins.
• Streptocin A exhibits specific inhibitory activity against Gram-positive bacteria.
• The stability profile of streptocin A suggests its potential therapeutic applications.