Abstract Background Clostridium perfringens is a Gram-positive anaerobic bacterium causing severe diseases such as gas gangrene and pseudomembranosus colitis. that are generally due to the secretion of powerful extracellular toxins. The expression of toxin genes is mainly regulated by VirR. the response regulator of a two-component system. https://www.complxmind.com/product-category/books/