Inhibition of Staphylococcus aureus and spheroplasts of Gram-negative bacteria by an antagonistic compound produced by a strain of Lactobacillus plantarum

摘要: Abstract A strain of Lactobacillus plantarum was examined for production an extracellular antagonistic compound. Cellfree preparations, dialyzed to remove organic acids, were used in inhibition studies which revealed that Gram-positive bacteria sensitive. Among these, Staphylococcus aureus chosen further characterization the agent. The compound susceptible breakdown by proteolytic enzymes and its effect completely lost after heat treatment at 121°C 15 min. Ultrafiltration indicated agent had a molecular weight over 100, 000, suggesting complex protein-containing aggregate. found be highest low pH values S. shown able adapt Most Gram-negative resistant However, their transformation spheroplasts, removed most cell envelopes, these sensitized. conclusion is mechanism probably includes influence on surface.