Abstract
Reduced tissue perfusion leading to tissue ischemia is a central component of the pathogenesis of myonecrosis caused by Clostridium perfringens. The C. perfringens α-toxin has been shown capable of inducing these changes, but its potential synergy with perfringolysin O (θ-toxin) is less well understood. Similarly, Clostridium septicum is a highly virulent causative agent of spontaneous gas gangrene, but its effect on the microcirculation has not been examined. Therefore, the aim of this study was to use intravital microscopy to examine the effects of C. perfringens and C. septicum on the functional microcirculation, coupled with the use of isogenic toxin mutants to elucidate the role of particular toxins in the resultant microvascular perfusion deficits. This study represents the first time this integrated approach has been used in the analysis of the pathological response to clostridial toxins. Culture supernatants from wild-type C. perfringens induced extensive cell death within 30 min, as assessed by in vivo uptake of propidium iodide. Furthermore, significant reductions in capillary perfusion were observed within 60 min. Depletion of either platelets or neutrophils reduced the alteration in perfusion, consistent with a role for these blood-borne cells in obstructing perfusion. In addition, mutation of either the α-toxin or perfringolysin O structural genes attenuated the reduction in perfusion, a process that was reversed by genetic complementation. C. septicum also induced a marked reduction in perfusion, with the degree of microvascular compromise correlating with the level of the C. septicum α-toxin. Together, these data indicate that as a result of its ability to produce α-toxin and perfringolysin O, C. perfringens rapidly induces irreversible cellular injury and a marked reduction in microvascular perfusion. Since C. septicum induces a similar reduction in microvascular perfusion, it is postulated that this function is central to the pathogenesis of clostridial myonecrosis, irrespective of the causative bacterium.
Highlights
Gas gangrene is a life-threatening syndrome most commonly associated with invasion of tissue by the anaerobic bacterium, Clostridium perfringens type A
Clostridial myonecrosis is a life-threatening process induced by infection with species such as C. perfringens and C. septicum
In this study we used intravital microscopy to study microvascular blood flow in a muscle exposed to products of C. perfringens and C. septicum
Summary
Gas gangrene is a life-threatening syndrome most commonly associated with invasion of tissue by the anaerobic bacterium, Clostridium perfringens type A. The pathology of gas gangrene is highly complex, but is thought to be mediated by disruptions in tissue perfusion, associated with alterations in platelet aggregation and leukocyte margination [1,2]. Toxins produced by C. perfringens type A have been shown to be essential to the development of this pathology [2,3,4,5,6,7]. Preparations containing the C. perfringens a-toxin, which has phospholipase C and sphingomyelinase activity [10], and perfringolysin O, a cholesterol-dependent cytolysin, known as h-toxin [11], have been shown to induce rapid and irreversible reductions in muscle blood flow, via generation of intravascular platelet-leukocyte aggregates [6]. The precise mechanism of action of these toxins, in combination, requires further investigation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
