Milestones in Clostridium perfringens research since 1995.

Clostridium perfringens is an important human and veterinary pathogen, as well as a common member of the normal intestinal microbiota. By applying molecular approaches, substantial progress has been achieved since 1995 in understanding the pathogenicity and biology of this gram-positive, anaerobic, spore-forming bacterium. For example, there is now a much improved understanding of the structure and action of its "legacy" toxins (i.e., CPA, PFO, ETX, CPB, ITX and CPE) and the pathogenic importance of many of those toxins has now been clearly demonstrated. In addition, several new toxins have been discovered since 1995 and at least one of those new toxins (NetB) has been clearly linked to disease. The importance and diversity of mobile genetic elements, particularly conjugative plasmids, for pathogenicity and antibiotic resistance is now established. Several regulators controlling virulence gene expression have been identified and, in some cases, their regulatory mechanisms have been clarified. For some regulators, their importance for virulence has also been demonstrated. Lastly, there is also improved knowledge of sporulation and germination mechanisms for C. perfringens, as well as how sporulation contributes to disease transmission and pathogenesis for this bacterium. Despite these advances, some important questions about C. perfringens remain to be explored.