Histotoxic Clostridial Infections.

The pathogenesis of clostridial myonecrosis or gas gangrene involves an interruption to the blood supply to the infected tissues, often via a traumatic wound, anaerobic growth of the infecting clostridial cells, the production of extracellular toxins, and toxin-mediated cell and tissue damage. This review focuses on host-pathogen interactions in Clostridium perfringens-mediated and Clostridium septicum-mediated myonecrosis. The major toxins involved are C. perfringens α-toxin, which has phospholipase C and sphingomyelinase activity, and C. septicum α-toxin, a ß-pore-forming toxin that belongs to the aerolysin family. Although these toxins are cytotoxic, their effects on host cells are quite complex, with a range of intracellular cell signaling pathways induced by their action on host cell membranes.

Deficient Skeletal Muscle Regeneration after Injury Induced by a Clostridium perfringens Strain Associated with Gas Gangrene.

Gas gangrene, or clostridial myonecrosis, is usually caused by Clostridium perfringens and may occur spontaneously in association with diabetes mellitus, peripheral vascular disease, or some malignancies but more often after contamination of a deep surgical or traumatic lesion. If not controlled, clostridial myonecrosis results in multiorgan failure, shock, and death, but very little is known about the muscle regeneration process that follows myonecrosis when the infection is controlled. In this study, we characterized the muscle regeneration process after myonecrosis caused in a murine experimental infection with a sublethal inoculum of C. perfringens vegetative cells. The results show that myonecrosis occurs concomitantly with significant vascular injury, which limits the migration of inflammatory cells. A significant increase in cytokines that promote inflammation explains the presence of an inflammatory infiltrate; however, impaired interferon gamma (IFN-γ) expression, a reduced number of M1 macrophages, deficient phagocytic activity, and a prolongation of the permanence of inflammatory cells lead to deficient muscle regeneration. The expression of transforming growth factor ß1 (TGF-ß1) agrees with the consequent accumulation of collagen in the muscle, i.e., fibrosis observed 30 days after infection. These results provide new information on the pathogenesis of gas gangrene caused by C. perfringens, shed light on the basis of the deficient muscle regenerative activity, and may open new perspectives for the development of novel therapies for patients suffering from this disease.

Use of Viable Cryopreserved Umbilical Tissue for Soft Tissue Defects in Patients With Gas Gangrene: A Case Series.

INTRODUCTION: Gas gangrene is a rapidly progressive bacterial infection leading to necrosis that usually develops as a result of trauma or postoperative complications. This condition requires early diagnosis with immediate surgical intervention. With a poor prognosis, a high incidence of amputation, and comorbidities such as diabetes and peripheral vascular disease, patients with gas gangrene are put at further risk for surgical complications. OBJECTIVE: This case series reports the clinical outcomes of using a commercially available viable cryopreserved umbilical tissue (vCUT) in the surgical management of 10 patients (9 males, 1 female) with acute lower extremity gas gangrene. MATERIALS AND METHODS: All 10 patients had aggressive debridement and irrigation, followed by an intraoperative application of vCUT to cover the large, complex wounds with exposed bone, tendon, and soft tissue, which was fenestrated and sutured to the surrounding skin edges. RESULTS: The average wound size following debridement was 45.9 cm2 (range, 8 cm2-105 cm2). Average percent area reduction of the wounds at 4 weeks post-vCUT application was 68.4% (range, 49%-99.5%). The average length of hospital stay was 9 days (range, 2-16 days), and postdischarge patients were treated with negative pressure wound therapy and standard of care (nonadherent dressing, dry gauze, and mild compression) until wound closure was achieved (average, 3.3 months [range, 1.25-4.5 months]). With a 1-time application of vCUT, all patients reached complete wound closure with decreased time to closure, fewer complications, and a shorter duration of hospitalization as compared with traditional inpatient management of gas gangrene (incision and drainage with staged procedures). CONCLUSIONS: The positive clinical outcomes indicate that vCUT may be an effective aid as an intraoperative application to cover wounds following aggressive debridement in the presence of gas gangrene.

Clinical Serum Therapy: Benefits, Cautions, and Potential Applications.

Blood serum from immunized humans or animals (e.g., horses) contains relevant antibodies and has been used as serum therapy to treat many diseases or envenomation events. The effectiveness of blood serum was initially discovered in 1890 when Kitasato and von Behring observed the effectiveness of this type of therapy against diphtheria and tetanus. Serum therapies played an important role in the advancement of modern medicine prior to the development of penicillin and steroids. At present, several types of serum therapy remain in clinical use. However, some physicians have a limited understanding of the nature and the benefits of serum therapy and the factors that require particular attention. In this review, we set out to clarify the benefits, cautions, and potential applications of serum therapy in the context of conditions such as gas gangrene, diphtheria, botulism, and tetanus and bites from three snake species (mamushi, habu, and yamakagashi) and the redback spider. It is hoped that this review will help clinicians to learn about clinical serum therapies and become familiar with their applications.

Molecular and cellular basis of microvascular perfusion deficits induced by Clostridium perfringens and Clostridium septicum.

Reduced tissue perfusion leading to tissue ischemia is a central component of the pathogenesis of myonecrosis caused by Clostridium perfringens. The C. perfringens alpha-toxin has been shown capable of inducing these changes, but its potential synergy with perfringolysin O (theta-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 alpha-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 alpha-toxin. Together, these data indicate that as a result of its ability to produce alpha-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.

Gas gangrene and necrotizing fasciitis in the upper extremity.

Necrotizing soft tissue infections encompass a wide variety of clinical syndromes resulting from introduction of various pathogens into injured or devitalized tissue. The extent of microbial involvement in such tissue may range from simple contamination to overt and progressive local tissue necrosis, which, if untreated, may lead to septicemia and death. Early differentiation among these infections is not always possible, as there are overlapping classification criteria. These infections exist along a continuum of clinical severity with different etiological agents and associated medical conditions. The often subtle clues heralding the presence of a necrotizing soft tissue infection must be sought so that expeditious surgical debridement and broad-spectrum antibiotic management are initiated. Although experience enables the clinician to make a specific diagnosis based on early findings, aggressive and proper treatment of suspected infections remains the priority. The purpose of the article is to provide an overview of necrotizing soft tissue infections in the upper extremity, focusing on gas gangrene, or clostridial myonecrosis, and necrotizing fasciitis, to facilitate early diagnosis and optimal management of these lethal diseases.

Depletion of neurohypophyseal content of vasopressin in septic shock.

OBJECTIVES: To assess the mechanisms underlying the inappropriately low plasma vasopressin levels reported in septic shock. DESIGN: Prospective case series. SETTING: A 26-bed general medical intensive care unit at a university hospital. PATIENTS: Septic shock patients. MEASUREMENTS AND MAIN RESULTS: In three consecutive patients with septic shock, plasma vasopressin levels, circulating vasopressinase activity, baroreflex sensitivity, and neurohypophyseal vasopressin content were assessed. Plasma vasopressin concentration was unexpectedly within normal range in two patients (1.6 pg/mL and 1.8 pg/mL) and increased in one (16 pg/mL). In all cases, vasopressinase activity was undetectable, baroreflex sensitivity was decreased, and the high signal intensity of the posterior lobe of the pituitary gland on T1-weighted magnetic resonance images was absent. Magnetic resonance imaging and plasma vasopressin levels normalized after recovery from shock in the patient who survived. CONCLUSION: These data suggest that in septic shock, inappropriately low plasma levels of vasopressin are at least partly related to a depletion of vasopressin stores in the neurohypophysis.

Clostridium perfringens alpha-toxin induces rabbit neutrophil adhesion.

Clostridium perfringens alpha-toxin, which is one of the main agents involved in the development of gas gangrene, stimulates O(2)(-)production in neutrophils. Exposure of rabbit neutrophils to the alpha-toxin induced firm adhesion of the cells to fibrinogen and fibronectin. Incubation of rabbit neutrophils and neutrophil lysates with alpha-toxin led to the production of diacylglycerol (DG) and L-alpha-phosphatidic acid (PA), respectively. The toxin-induced DG and PA formation preceded the toxin-induced adhesion of the neutrophils to fibrinogen and fibronectin, and the production of O(2)(-). Pertussis toxin inhibited the alpha-toxin-induced formation of PA, the adhesion of the neutrophils to fibrinogen and production. GTP gamma S stimulated the events induced by the alpha-toxin, whereas GDP beta S inhibited them. The alpha-toxin stimulated phosphorylation of a protein with a molecular mass of about 40 kDa. In addition, treatment of the cells with 1-oleoyl-2-acetyl-sn-glycerol (OAG) and phorbol-12,13-dibutyrate (PDBu) stimulated cell adhesion, production of and phosphorylation of the 40 kDa protein, but had no effect on the formation of PA. The events induced by the presence of OAG and PDBu were not inhibited by pertussis toxin. Protein kinase C inhibitors, H-7, staurosporine and chelerythrine, blocked alpha-toxin-induced adhesion, production of O(2)(-)and phosphorylation of the 40 kDa protein. These observations suggested that alpha-toxin-stimulated adhesion to the matrix and production were due to the formation of DG, through activation of phospholipid metabolism by a pertussis-toxin-sensitive GTP-binding protein, followed by activation of protein kinase C by DG.

Clostridial gas gangrene. I. Cellular and molecular mechanisms of microvascular dysfunction induced by exotoxins of Clostridium perfringens.

Mechanisms responsible for the rapid tissue destruction in gas gangrene are not well understood. To examine the early effects of Clostridium perfringens exotoxins on tissue perfusion, a rat model of muscle blood flow was developed. Intramuscular injection of a clostridial toxin preparation containing both phospholipase C (PLC) and theta-toxin caused a rapid (1-2 min) and irreversible decrease in blood flow that paralleled formation of activated platelet aggregates in venules and arterioles. Later (20-40 min), aggregates contained fibrin and leukocytes, and neutrophils accumulated along vascular walls. Flow cytometry confirmed that these clostridial toxins or recombinant PLC induced formation of P-selectin-positive platelet aggregates. Neutralization of PLC activity in the clostridial toxin preparation completely abrogated human platelet responses and reduced perfusion deficits. It is concluded that tissue destruction in gas gangrene is related to profound attenuation of blood flow initiated by activation of platelet responses by PLC.

Free gracilis muscle transplantation for hand reconstruction.

Free muscle transplantation with motor innervation is the only way to add contractile elements to upper extremities with extensive loss of musculature due to direct trauma or untreated compartment syndrome (Volkmann's contracture). The functional cross-sectional area and the mean resting fiber length determine the maximum power and the contracting amplitude of the donor muscle, respectively. Although considerably weaker than the finger flexors to be replaced, the gracilis muscle was the preferred donor muscle because of the consistent anatomy of its neurovascular pedicle and the minimal donor site morbidity. In a series of 15 gracilis transplantations, all 13 muscles that survived regained function. Finger motion was dependent on the preoperative condition of tendons and joints. Even after complete loss of the flexor and extensor compartment after direct trauma or infection, a useful upper extremity could be restored, which was preferable to the only alternative--amputation.

Role of alpha-toxin in Clostridium perfringens infection determined by using recombinants of C. perfringens and Bacillus subtilis.

Clostridium perfringens type A strains which differed in alpha-toxin (phospholipase C [PLC]) productivity were inoculated intraperitoneally or intravenously into mice, and then their 50% mouse lethal doses (LD50) were determined. Strain NCTC 8237 produced ninefold higher PLC activity than strain 13. The mean LD50 for the former was 1 log unit lower than that for the latter. Two isogenic strains were constructed from strain 13: strain 13(pJIR418 alpha) (pJIR418 alpha contains the plc gene), which produced ninefold higher PLC activity than strain 13; and strain 13 PLC-, which showed no PLC productivity at all because of transformation-mediated gene disruption. The mean LD50 for strain 13(pJIR418 alpha) was 1 log unit lower than those for strain 13 PLC- and strain 13. These results indicate that PLC functions as a virulence-determining factor when it is produced in a sufficient amount. Such a difference in LD50 was also observed between Bacillus subtilis with and without the cloned plc gene. Inoculation of B. subtilis PLC+ intravenously into mice caused marked thrombocytopenia and leukocytosis. Mice inoculated with B. subtilis at 2 LD50 died because of circulatory collapse. Histological examination revealed that intravascular coagulation and vascular congestion occurred most prominently in the lungs. These results suggest that PLC plays a key role in the systemic intoxication of clostridial myonecrosis, probably by affecting the functions of platelets and phagocytes.

Clinical courses of seven survivors of Clostridium septicum infection and their immunologic responses to alpha toxin.

Clostridium septicum bacteremia typically portends a fulminant disease associated with high mortality. We describe the clinical courses of seven survivors of C. septicum infection and their antibody responses to the alpha toxin produced by C. septicum. Three patients had clinical syndromes ranging from uncomplicated bacteremia to early typhlitis, and three patients had syndromes ranging from abscess to myonecrosis and septic shock. In addition, an AIDS patient who developed septic shock and who had extensive gas in the retroperitoneal musculature did not undergo surgery but survived after receiving antimicrobial therapy and intensive supportive care. Both immunocompetent patients with myonecrosis had detectable IgG to alpha toxin by immunoblot analysis. IgG to alpha toxin was not detected in the four immunocompetent patients who had C. septicum bacteremia but who did not have myonecrosis or in the AIDS patient with myonecrosis. Therefore, humoral responses to alpha toxin during C. septicum infection may be related to the host's clinical syndrome and immune status.

Hyperbaric oxygen in the treatment of gas gangrene and perineal necrotizing fasciitis. A clinical and experimental study.

Between 1971 and 1987, 32 patients with clostridial gas gangrene were treated in the Department of Surgery, University of Turku. A presumptive diagnosis of gas gangrene was made on the basis of the clinical appearance of the patient and a predominance of Gram positive rods on stain. Between 1973 and 1989, 11 patients with perineal necrotizing fasciitis (Fournier's gangrene) were treated. The diagnosis was based on fulminating progression of perineal gangrene and on the presence of multiple pathogenic organisms in the primary Gram stain or culture. All patients in both series underwent surgical debridement, antibiotic therapy, and intensive care. In addition, the patients were exposed to pure oxygen at 2.5 atmospheres absolute pressure (ATA) for 120 minutes. Three such treatments were given during the first 24 hours after admission after which the treatment was repeated twice daily. Seventeen patients with clostridial gas gangrene had diffusely spreading myonecrosis; 6 died. Fifteen patients developed clostridial cellulitis with toxicity; 3 died. Thus, the overall mortality in gas gangrene was 28%. All the 9 patients who died had been transferred from other hospitals in Finland and were moribund on arrival. The infection in 8 of these patients developed postoperatively. None of the patients with a posttraumatic infection died. Each of the patients with Fournier's gangrene had had nonspecific symptoms before the gangrene became evident. The infection originated from the anorectal area in 5 patients, 1 patient had sustained a scrotal trauma and in 5 patients the underlying condition was unknown. One patient died 2 days after admission. Six patients required a colostomy. To evaluate the therapeutic value of hyperbaric oxygen (HBO) treatment, two experimental models of clostridial gas gangrene, mono- and multimicrobial, were developed in rats. In the monomicrobial infection model, 10(7) colony forming units (cfu) of Clostridium perfringens were injected intramuscularly into the left hind limb of the rat. The mortality of untreated rats was 100%. The mortality of the rats treated with surgery alone was 38% compared to 13% when surgery was used in combination with HBO (p < 0.01; chi 2 test). In the group treated with HBO and surgery, 94% of the survivors healed completely and were able to walk normally, whereas the corresponding figure in the rats treated with surgery alone was 20% (p < 0.001; chi 2-test). In the multimicrobial gas gangrene model the infection was induced by an intramuscular injection of a mixture containing approximately 10(7) cfu of each of the following bacteria: Clostridium perfringens, Bacteroides fragilis, Escherichia coli and Streptococcus faecalis.(ABSTRACT TRUNCATED AT 400 WORDS)

Gas gangrene. A review.

Gas gangrene continues to cause significant morbidity and mortality. This monograph reviews the entire spectrum of clostridial infection, including its etiology, pathophysiology, diagnosis, current recommended treatment, and prophylaxis. The early diagnosis of gas gangrene is paramount, as delay in aggressive combined treatment may result in death.

Gas gangrene: certain diagnosis or certain death.

Clostridia are organisms which, in the right environment, can cause a rapidly spreading, fulminant myonecrosis. Early diagnosis and a combined management program are clearly paramount to a successful outcome. Knowledge of this disease and ongoing meticulous assessment are the tools that a nurse must use when dealing with patients who have gas gangrene or are at high risk of developing it. In the face of radical disfigurements that may follow therapeutic measures, the potential transfer to a distant center for treatment, and a deteriorating prognosis, the nurse must remain alert to patient and family psychologic needs.

[Fatal appendectomy caused by postoperative gas gangrene of the abdominal wall. 2 cases]. / Appendicectomie mortelle par gangrène gazeuse pariétale post-opératoire. 2 cas.

The authors report two cases of post-appendicectomy gas gangrene with a fatal outcome. Based on the study of these two cases they analyse the incidence, mechanism and prognosis of this serious post-operative complication. They stress the prophylactic measures necessary for prevention.