Spontaneous C. septicum gas gangrene: A literature review

Perforation of descending colonic cancer as a rare cause of gas gangrene of the lower limb in an 80-year-old female: a case report

Gas gangrene is a rare, severe gas-producing infection that can be related to colorectal cancer. Gas gangrene can be confirmed by radiologic findings and crepitation on touch. Spontaneous gas gangrene can be associated with colorectal cancer. An 80-year-old female complaint about a sudden abdominal pain, accompanied with progressive swelling pain in thigh and fever. Diagnosis based on assessment findings were gas gangrene and descending colonic cancer perforation. Emergency surgery was performed for debridement and drainage, followed by vacuum sealing drainage (VSD) with polyurethane (PU). Two more surgical interventions were given before the colonic tumor surgery. The patient recovered well in the long-term follow-up. This report demonstrates the diagnosis, treatment, and management of a successful case of gas gangrene caused by perforation of descending colonic cancer. Accurate preoperative diagnosis and reasonable use of VSD (PU) material played an important role in the treatment of this case.

Clostridium septicum Bacteremia As the Presenting Sign of Colon Cancer

Colon cancer is one of the leading causes of morbidity and mortality throughout the world. Some of the most common presenting signs are a change in bowel habits, alteration of fecal contour or consistency, blood in stool, fatigue, and weight loss. However, it may present insidiously. This is the case of an 81-year-old female with Clostridium septicum bacteremia as the primary presenting sign of metastatic colon cancer. In further literature review, we discuss the genomic associations that contribute to the severity of the disease and explore the potential links between the gut microbiome and colorectal carcinoma. This article highlights risk factor modifications and lab abnormalities that may be useful for the primary care provider and acute care practitioner.

Clostridium septicum myonecrosis following gardening: A case report

INTRODUCTION AND IMPORTANCE

Clostridial myonecrosis (CM), or gas gangrene, is a rare necrotizing muscle infection caused most often by Clostridium perfringens or C. septicum. Inoculation can occur either traumatically or spontaneously. CM has a high mortality rate if not treated promptly.

CASE PRESENTATION

A 64-year-old male presented to the emergency department (ED) with sudden onset left flank pain and fever. Repeated CT scans demonstrated progressive edema around the left iliopsoas muscle with gas formation and bleeding. The patient received intravenous fluids, meropenem, and clindamycin. Emergency laparotomy was performed on suspicion of necrotizing fasciitis and revealed a necrotic left iliopsoas muscle which was partially excised. Blood cultures were positive at 12 h with growth of C. septicum. Prolonged stay in the intensive care unit, and six additional surgical interventions to the abdomen, left thigh, and flank were needed. The patient was discharged after four months to a nursing home.

CLINICAL DISCUSSION

C. septicum CM more often occurs spontaneously and is associated with colorectal malignancy. However, for our patient, CT colonography and proctoscopy did not reveal any pathology. Therefore, we believe the CM resulted from an injury the patient sustained while working in his backyard, either a cut from barbed wire on his arm or from soil contaminating his psoriatic lesions. Successful outcomes for patients with CM require a high index of suspicion, timely treatment with antibiotics, and repeated surgical debridements.

CONCLUSION

This case report describes the presentation and management of a presumably injury-related CM caused by C. septicum.

Postpartum clostridial gangrenous metritis in 12 dairy goats in France

Clostridial infections in goats have been associated frequently with enteric diseases or gas gangrene but very rarely with the reproductive system. We describe here 12 cases of fatal postpartum gangrenous metritis in does associated with infection by several clostridial species. Clinically, these cases were characterized by rapid onset of hyperthermia followed by death after kidding. On postmortem examination, the uteri appeared to be necrotic and were hemorrhagic and edematous. Microscopically, the uteri had diffuse coagulative necrosis, edema, hemorrhage, and fibrinous thrombi with intralesional gram-positive rods. Clostridium perfringens was isolated from 7 of 9 uterine samples cultured, and C. perfringens, C. septicum, C. novyi, or C. chauvoei were demonstrated by immunohistochemistry (IHC) in the 5 cases examined. IHC for Paeniclostridium sordellii was negative in all 5 cases. PCR performed on 3 of the C. perfringens isolates was positive for alpha toxin and perfringolysin, identifying these isolates as type A. Clostridial infection should be considered in cases of postpartum gangrenous metritis of does.

Tracking a Fatal Disease: Lower Limb Gas Gangrene's Mortality-Related Factors

Introduction

Because of its rarity compared to dry and wet gangrene of the lower limb, the gaseous form has often been considered as the most severe form of gangrenous disease. We aimed to report clinical, paraclinical, and therapeutic features, and to identify mortality risk factors of gas gangrene of the lower limb.

Patients and Methods

We conducted a one-center case series retrospective study over a period of 13 years from January 2006 to December 2018.

Results

A total of 19 patients were included: 12 men, 7 women. Mean age was 59.3  ±  11.3 years. There were 17 diabetic patients and one patient was on radio-chemotherapy for lower rectal cancer. Septic shock was initially present in 4 cases. Hyperleukocytosis was noted in 17 patients. C-reactive protein was elevated in 11 patients. All patients were put on antibiotics then operated on. A total of 8 patients died postoperatively (42%) in an average time of 9.6 days after surgery. On univariate analysis, factors associated with mortality were: Septic shock on admission (p  =  0.02); local signs limited to foot (p  =  0.05) or extended above the knee (p  =  0.02); leukocytosis (p  =  0.005); glycemia level (p  =  0.02); antibiotic therapy duration (p  =  0.04); antibiotic association of Penicillin G, metronidazole, and gentamicin (p  =  0.02); amputation procedure solely (p  =  0.04) or debridement procedure without amputation (p  =  0.05); intraoperative transfusion (p  =  0.006); and hospital stay (p  =  0.01).

Conclusion

Identifying gas gangrene mortality factors is fundamental to standardize management. Our study was able to build on the small size of our series, but further prospective and large-scale studies are required.

Modulatory Effect of Gut Microbiota on the Gut-Brain, Gut-Bone Axes, and the Impact of Cannabinoids

The gut microbiome is a collection of microorganisms and parasites in the gastrointestinal tract. Many factors can affect this community's composition, such as age, sex, diet, medications, and environmental triggers. The relationship between the human host and the gut microbiota is crucial for the organism's survival and development, whereas the disruption of this relationship can lead to various inflammatory diseases. Cannabidiol (CBD) and tetrahydrocannabinol (THC) are used to treat muscle spasticity associated with multiple sclerosis. It is now clear that these compounds also benefit patients with neuroinflammation. CBD and THC are used in the treatment of inflammation. The gut is a significant source of nutrients, including vitamins B and K, which are gut microbiota products. While these vitamins play a crucial role in brain and bone development and function, the influence of gut microbiota on the gut-brain and gut-bone axes extends further and continues to receive increasing scientific scrutiny. The gut microbiota has been demonstrated to be vital for optimal brain functions and stress suppression. Additionally, several studies have revealed the role of gut microbiota in developing and maintaining skeletal integrity and bone mineral density. It can also influence the development and maintenance of bone matrix. The presence of the gut microbiota can influence the actions of specific T regulatory cells, which can lead to the development of bone formation and proliferation. In addition, its metabolites can prevent bone loss. The gut microbiota can help maintain the bone's equilibrium and prevent the development of metabolic diseases, such as osteoporosis. In this review, the dual functions gut microbiota plays in regulating the gut-bone axis and gut-brain axis and the impact of CBD on these roles are discussed.

Spontaneous gas gangrene of the lower limb in a patient with rectal cancer: A fatal diagnostic pitfall

Spontaneous gas gangrene of lower limb is rare. It may complicate digestive cancer or neutropenia. We report a case of spontaneous gas gangrene of the lower limb complicating a rectal cancer, initially diagnosed as deep vein thrombosis. The diagnostic delay was fatal.

Prospects of conservative treatment for Clostridium septicum–associated aortitis

Clostridium septicum bacteremia is a rare (72 cases reported) aneurysm-inducing disease that has resulted in a 6-month mortality of 100% when treated conservatively. We report the case of a patient who was completely symptom free at 6 months of follow-up but who ultimately died at 8.9 months after aortic rupture. In compliance with the patient’s choice, a long-time antibiotic regimen was applied, instead of the surgical approach recommended by our surgical department. The use of an antibiotic regimen represents an option for patients unfit for surgery or as a bridge to surgery for damage control; however, aortic repair represents the only curative approach. Definitive antibiotic treatment is limited to a palliative approach for patients with C. septicum aortitis and has been accompanied by 100% 1-year mortality (90-day mortality, 84.2%).

Clostridium septicum α-toxin activates the NLRP3 inflammasome by engaging GPI-anchored proteins

Clostridium species are a group of Gram-positive bacteria that cause diseases in humans, such as food poisoning, botulism, and tetanus. Here, we analyzed 10 different Clostridium species and identified that Clostridium septicum, a pathogen that causes sepsis and gas gangrene, activates the mammalian cytosolic inflammasome complex in mice and humans. Mechanistically, we demonstrate that α-toxin secreted by C. septicum binds to glycosylphosphatidylinositol (GPI)-anchored proteins on the host plasma membrane, oligomerizing and forming a membrane pore that is permissive to efflux of magnesium and potassium ions. Efflux of these cytosolic ions triggers the activation of the innate immune sensor NLRP3, inducing activation of caspase-1 and gasdermin D, secretion of the proinflammatory cytokines interleukin-1β and interleukin-18, pyroptosis, and plasma membrane rupture via ninjurin-1. Furthermore, α-toxin of C. septicum induces rapid inflammasome-mediated lethality in mice and pharmacological inhibition of the NLRP3 inflammasome using MCC950 prevents C. septicum-induced lethality. Overall, our results reveal that cytosolic innate sensing of α-toxin is central to the recognition of C. septicum infection and that therapeutic blockade of the inflammasome pathway may prevent sepsis and death caused by toxin-producing pathogens.

A Case of Forearm Soft Tissue Infection Caused by Hypervirulent K. pneumoniae in an Otherwise Healthy 24-Year-Old Woman

In recent years, hypervirulent Klebsiella pneumoniae (hvKp) has received greater attention. It mainly infects diabetic patients and typically causes a hepatic abscess. Here, we report a case of hvKp that caused forearm muscle and soft tissue infection in addition to bacteremia, hepatic and pulmonary abscess, and hyperglycemia. The patient’s condition stabilized after comprehensive treatment. She eventually recovered and was discharged after several debridement and flap operations. At 9 months of follow-up, no signs of infectious recurrence were noted, and the hyperglycemia resolved. Here, we detail important clinical features of a severe hvKp case diagnosed in an otherwise healthy individual. This report underscores the potential of hvKp to cause deep tissue infection and present with clinical symptoms similar to gas gangrene. Symptom onset in the setting of hvKp infection is usually gradual and misdiagnosis is common. The diagnosis of hvKp should be routinely considered in the clinical setting, and be strongly suspected when presenting with characteristic epidemiological, clinical and laboratory features. Although diabetes is a predisposing factor to hvKp infection, hyperglycemia appeared to manifest as a consequence of hvKp infection in this patient.

First Comparative Analysis of Clostridium septicum Genomes Provides Insights Into the Taxonomy, Species Genetic Diversity, and Virulence Related to Gas Gangrene

Clostridium septicum is a Gram-positive, toxin-producing, and spore-forming bacterium that is recognized, together with C. perfringens, as the most important etiologic agent of progressive gas gangrene. Clostridium septicum infections are almost always fatal in humans and animals. Despite its clinical and agricultural relevance, there is currently limited knowledge of the diversity and genome structure of C. septicum. This study presents the complete genome sequence of C. septicum DSM 7534T type strain as well as the first comparative analysis of five C. septicum genomes. The taxonomy of C. septicum, as revealed by 16S rRNA analysis as well as by genomic wide indices such as protein-based phylogeny, average nucleotide identity, and digital DNA–DNA hybridization indicates a stable clade. The composition and presence of prophages, CRISPR elements and accessory genetic material was variable in the investigated genomes. This is in contrast to the limited genetic variability described for the phylogenetically and phenotypically related species Clostridium chauvoei. The restriction-modification (RM) systems between two C. septicum genomes were heterogeneous for the RM types they encoded. C. septicum has an open pangenome with 2,311 genes representing the core genes and 1,429 accessory genes. The core genome SNP divergence between genome pairs varied up to 4,886 pairwise SNPs. A vast arsenal of potential virulence genes was detected in the genomes studied. Sequence analysis of these genes revealed that sialidase, hemolysin, and collagenase genes are conserved compared to the α-toxin and hyaluronidase genes. In addition, a conserved gene found in all C. septicum genomes was predicted to encode a leucocidin homolog (beta-channel forming cytolysin) similar (71.10% protein identity) to Clostridium chauvoei toxin A (CctA), which is a potent toxin. In conclusion, our results provide first, valuable insights into strain relatedness and genomic plasticity of C. septicum and contribute to our understanding of the virulence mechanisms of this important human and animal pathogen.

Clostridium septicum myonecrosis in a pediatric patient with a self-reported penicillin allergy

Infections with Clostridium septicum are especially rare in pediatric patients. C. septicum is the most common cause of spontaneous myonecrosis and is usually associated with comorbid malignancy. Treatment of choice for cases of C. septicum myonecrosis is prompt and thorough surgical debridement and antimicrobial therapy with high dose penicillin. The experience and management of C. septicum infections in patients who are unable to take penicillin are not well described, and the optimal duration of therapy is largely unknown. We describe a case of spontaneous myonecrosis in a 14-year-old receiving cytotoxic chemotherapy for Burkitt's lymphoma who had an anecdotal history of a penicillin allergy. Her infection was initially treated with ceftazidime and metronidazole in concert with debridement but was ultimately cured with 3 weeks of intravenous penicillin therapy following a graded penicillin challenge in hospital. We observed a delayed inflammatory tissue response to a C. septicum skin, soft tissue infection that temporally corresponded to neutrophil reconstitution in our patient with severe neutropenia. Our experience demonstrates that C. septicum myonecrosis can present indolently and progress rapidly and highlights the need for clinical vigilance and repeat "second-look" surgeries. Our case also emphasizes the importance of de-labelling penicillin allergies.

Non-C. difficile Clostridioides Bacteremia in Intensive Care Patients, France

Article Summary: This multicenter study focusing on critically ill patients showed a strong relationship between hemolysis and mortality.

Usually responsible for soft tissue infections, Clostridioides species can also cause bacteremia, life-threatening infections often requiring intensive care unit (ICU) admission. We conducted a multicenter retrospective study to investigate Clostridioides bacteremia in ICUs to describe the clinical and biologic characteristics and outcomes in critically ill patients. We identified 135 patients with Clostridioides bacteremia, which occurred almost exclusively (96%) in patients with underlying conditions. Septic shock and digestive symptoms were the hallmarks of Clostridioides bacteremia in the ICU. We identified 16 different species of Clostridioides, among which C. perfringens accounted for 31% of cases. Despite the high sensitivity of Clostridioides to common antimicrobial drugs, mortality rates were high: 52% for ICU patients and 71% overall at 3 months. In multivariate analysis, the most important factor associated with increased risk for death was the presence of hemolysis. Clostridioides bacteremia often leads to multiple organ failures, which have high mortality rates.

Necrotizing soft tissue infection: clinical characteristics, diagnosis, and management of 32 cases in Beijing

OBJECTIVE

Necrotizing soft tissue infection (NSTI) is a rare but life-threatening bacterial infection. This study was performed to analyze the clinical characteristics of patients with NSTI admitted to the intensive care unit of a trauma and burn center in Beijing and to summarize the treatment experience.

METHODS

This retrospective study involved patients with NSTI admitted to the intensive care unit from January 2010 to January 2020. The clinical manifestations, pathogens, laboratory test results, and prognosis were compared between survivors and nonsurvivors.

RESULTS

Thirty-two patients were enrolled (28 men, 4 women), including 25 (78.1%) survivors and 7 (21.9%) nonsurvivors. The patients' median age was 41.5 years (range, 30.0-52.5 years). Mortality was significantly higher in patients with a blood urea nitrogen concentration of ≥11.5 mg/dL, creatinine concentration of <3.4 mg/dL, prothrombin time of ≥15.9 s, and international normalized ratio of ≥1.3. Streptococcus pyogenes and Clostridium perfringens infections were associated with higher mortality.

CONCLUSIONS

More attention should be given to elderly patients and those with hyponatremia, coagulation disorder, and higher blood urea nitrogen or creatinine concentrations. The finding of large gram-positive rods or large numbers of gram-positive cocci in wound secretion smears is a helpful early warning sign of highly lethal NSTI.

Rapidly progressive and fatal distant spontaneous gas gangrene due to Clostridium septicum after biopsy of malignant cecal mass

Clostridium species are known to cause myonecrosis and gas gangrene which are often fatal infections in the setting of trauma but also spontaneously in certain populations such as colorectal malignancy, immunosuppression, and neutropenia. We report a case of an 83-year-old male who developed fatal and rapidly progressive gas gangrene due to Clostridium septicum within 48 h after biopsy of suspected malignant cecal mass. To our knowledge, such a drastic, rapid and fatal presentation after a diagnostic biopsy of malignant mass has not been previously reported and is something to be watchful for in suspected colon cancer cases.

Essential oil combinations against Clostridium perfringens and Clostridium septicum - the causative agents of gas gangrene

AIMS

The inhibitory and bactericidal effect of a wide range of essential oils, and their selected combinations against two pathogens (Clostridium perfringens and Clostridium septicum), the causative pathogens of gas gangrenous infections were investigated. Fractional inhibitory indices were also calculated to determine the interactions.

METHODS AND RESULTS

The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays were used to determine the efficacy of the essential oils. Santalum austrocaledonicum demonstrated the highest activity inhibiting both Clostridial pathogens at the lowest concentration of 0·02 mg ml^-1 . Santalum austrocaledonicum combined with Cymbopogon martinii had the strongest inhibition against C. perfringens (MIC 0·02 mg ml^-1 ) and C. septicum (MIC 0·01 mg ml^-1 ). Selected combinations demonstrated synergy (ΣFIC ≤ 0·50) in combination against both pathogens tested. Antagonism was also observed in many combinations.

CONCLUSIONS

Selected essential oils, when studied either individually or in combination, have high inhibitory and bactericidal effects against both Clostridial strains. Nine combinations have proven to be synergistic with 23 combinations additive; 96 indifferent and 77 having an antagonistic effect against the pathogenic strains. Some combinations demonstrated extreme antagonism and as such, careful consideration needs to be given to essential oil selection against these pathogens.

SIGNIFICANT IMPACT OF THE STUDY

Very few essential oils have been antimicrobially screened (MIC and MBC) against Clostridial strains and furthermore, the efficacies in combination are not known.

Necrotizing fasciitis associated with malignancy

Necrotizing fasciitis (NF) is a rare soft-tissue condition with a high mortality rate even with treatment. Diagnosis is challenging due to an absence of specific symptoms at the early stages of clinical presentation. NF is typically associated with traumatic injuries, superficial skin breakdown, and surgical procedures. Diabetes mellitus and immunosuppression also increase the risk of developing NF. NF predominantly occurs in the lower extremities, the peritoneum, and the perineum. Treatments include antimicrobials, supportive care, and surgical source control. It is important for clinicians to recognize the association of spontaneous atraumatic NF caused by Clostridium septicum with malignancy, so they can maintain a high index of suspicion and provide timely interventions to optimize patient outcomes.

Clostridial Gas Gangrene - A Rare but Deadly Infection: Case series and Comparison to Other Necrotizing Soft Tissue Infections

Objective

Clostridial gas gangrene (GG) or clostridial myonecrosis is a very rare but life‐threatening necrotizing soft tissue infection (NSTI) caused by anaerobic, spore‐forming, and gas‐producing clostridium subspecies. It is the most rapidly spreading and lethal infection in humans, also affecting muscle tissue. The high mortality, of up to 100%, in clostridial GG is mediated by potent bacterial exotoxins. Necrotizing fasciitis (NF) is an important differential diagnosis, most often caused by group A streptococci, primarily not affecting musculature but the subcutaneous tissue and fascia. In the early stages of the infection, it is difficult to distinguish between GG and NF. Therefore, we compare both infection types, identify relevant differences in initial clinical presentation and later course, and present the results of our patients in a retrospective review.

Methods

Patients diagnosed with GG from 2008 to 2018 in our level one trauma center were identified. Their charts were reviewed retrospectively and data analyzed in terms of demographic information, microbiological and histological results, therapeutic course, outcome, and mortality rates. The laboratory risk indicator for NF (LRINEC) score was applied on the first blood work acquired. Results were compared to those of a second group diagnosed with NF.

Results

Five patients with GG and nine patients with NF were included in the present study. Patients with GG had a mortality rate of 80% compared to 0% in patients with NF. In eight patients with NF, affected limbs could be salvaged; one NF underwent amputation. LRINEC did not show significant differences between the groups; however, C‐reactive protein was significantly increased (P = 0.009) and hemoglobin (Hb) was significantly decreased (P = 0.02) in patients with GG. Interleukin‐6 and procalcitonin levels did not show significant difference. Patients with GG were older (70.2 vs 50 years). Of the isolated bacteria, 86% were sensitive to the initial calculated antibiotic treatment with ampicillin‐sulbactam or imipenem plus metronidazole plus clindamycin.

Conclusion

Both GG and NF need full‐scale surgical, antibiotic, and intensive care treatment, especially within the first days. Among patients with NSTI, those with clostridial GG have a significantly increased mortality risk due to early septic shock caused by clostridial toxins. In the initial stages, clinical differences are hardly detectable. Immediate surgical debridement is the key to successful therapy for NSTI and needs to be performed as early as possible. However, patients should be treated in a center with an experienced interdisciplinary intensive care team based on a predetermined treatment plan.

Distant myonecrosis by atraumatic Clostridium septicum infection in a patient with metastatic breast cancer

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Atraumatic Clostridium septicum infection is seen in metastatic breast cancer.

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Rapid identification and aggressive treatment atypical of clostridial species is required.

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Atraumatic infection may require debridement beyond visible necrosis.

Clostridium septicum is an anaerobic, gram-positive bacillus known to cause myonecrosis, also known as gas gangrene, a life-threatening necrotizing soft tissue infection. Though it accounts for just 1 % of all infections attributable to Clostridia spp., C. septicum is a highly virulent and aggressive pathogen. Classic presentations of infection include bacteremia resulting in shock, myonecrosis, and vascular seeding. C. septicum-associated gas gangrene most commonly occurs in the setting of traumatic injury, but has also been reported in patients with colorectal malignancy, immunosuppression, neutropenia, and exceedingly rare in association with breast cancer. We report the case of a 56-year-old female patient with stage IV mixed lobar and ductal breast carcinoma with metastasis to the bone and liver, who presented with spontaneous C. septicum myonecrosis of the right hand. No prior traumatic injury was noted. Following amputation of the right forearm, antibiotic treatment, and multiorgan support, the patient passed following transition to palliative care. We hope to increase awareness of this relatively uncommon, though potentially deadly pathogen, as well as to discuss treatment options in patients infected with C. septicum.

Colon Adenocarcinoma Associated With Clostridium Septicum Endophthalmitis Detected on 18F-FDG PET/CT

Endogenous Clostridium septicum endophthalmitis is a rare and fulminant ocular infection, usually encountered in immunocompromised or diabetic patients. It is also highly associated with both gastrointestinal and hematologic malignancies. We describe herein the detection of an adenocarcinoma of the cecum on PET/CT with F-FDG in a patient with an active endogenous C. septicum endophthalmitis of the right eye. FDG PET/CT should be considered for all patients with endogenous endophthalmitis to exclude an occult malignancy, especially colorectal cancer.

Genomics of the Pathogenic Clostridia

Whole-genome sequences are now available for all the clinically important clostridia and many of the lesser or opportunistically pathogenic clostridia. The complex clade structures of C. difficile, C. perfringens, and the species that produce botulinum toxins have been delineated by whole-genome sequence analysis. The true clostridia of cluster I show relatively low levels of gross genomic rearrangements within species, in contrast to the species of cluster XI, notably C. difficile, which have been found to have very plastic genomes with significant levels of chromosomal rearrangement. Throughout the clostridial phylotypes, a large proportion of the strain diversity is driven by the acquisition and loss of mobile elements, including phages, plasmids, insertion sequences, and transposons. Genomic analysis has been used to investigate the diversity and spread of C. difficile within hospital settings, the zoonotic transfer of isolates, and the emergence, origins, and geographic spread of epidemic ribotypes. In C. perfringens the clades defined by chromosomal sequence analysis show no indications of clustering based on host species or geographical location. Whole-genome sequence analysis helps to define the different survival and pathogenesis strategies that the clostridia use. Some, such as C. botulinum, produce toxins which rapidly act to kill the host, whereas others, such as C. perfringens and C. difficile, produce less lethal toxins which can damage tissue but do not rapidly kill the host. The genomes provide a resource that can be mined to identify potential vaccine antigens and targets for other forms of therapeutic intervention.

Clostridium septicum-infected aortic aneurysm or graft is a deadly diagnosis

BACKGROUND

Clostridium septicum is an anaerobic, motile, spore-forming, toxin-producing gram-positive bacillus that can lead to rapidly progressive gas gangrene due to the release of alpha toxin. Aortic aneurysm secondary to C. septicum infection is a rare condition with 60 cases reported in the literature; however, we have recently treated several patients with the condition in our large tertiary care and aortic center.

METHODS

Blood and tissue culture results collected between January 2005 and January 2018 and maintained in the microbiology laboratory database at the Cleveland Clinic were reviewed to identify those with C. septicum reported. Each was reviewed to determine radiographic or histopathologic correlation with aortic disease.

RESULTS

Seven cases of C. septicum aortitis were reviewed. Underlying malignant disease was found in four cases and a history of remote malignant disease in one case. The most common location for infection was the infrarenal abdominal aorta. Vascular surgery had previously been performed in three of the cases. Five of the seven patients underwent operative repair. All patients were treated with β-lactam antibiotics. The two patients who did not undergo an operation died, which is consistent with the 100% mortality described in the literature. Of the five patients who underwent an operation, there was only one documented survivor and one was lost to follow-up.

CONCLUSIONS

In the largest reported case series, only a small percentage of patients with C. septicum-infected aortic aneurysms survived >1 year. In the patients described, those who did not receive an operation had 100% mortality. Earlier recognition and prompt operation with appropriate antimicrobial therapy are needed to improve the outcome of patients diagnosed with this rare infection.

Vaccine Production to Protect Animals Against Pathogenic Clostridia

Clostridium is a broad genus of anaerobic, spore-forming, rod-shaped, Gram-positive bacteria that can be found in different environments all around the world. The genus includes human and animal pathogens that produce potent exotoxins that cause rapid and potentially fatal diseases responsible for countless human casualties and billion-dollar annual loss to the agricultural sector. Diseases include botulism, tetanus, enterotoxemia, gas gangrene, necrotic enteritis, pseudomembranous colitis, blackleg, and black disease, which are caused by pathogenic Clostridium. Due to their ability to sporulate, they cannot be eradicated from the environment. As such, immunization with toxoid or bacterin-toxoid vaccines is the only protective method against infection. Toxins recovered from Clostridium cultures are inactivated to form toxoids, which are then formulated into multivalent vaccines. This review discusses the toxins, diseases, and toxoid production processes of the most common pathogenic Clostridium species, including Clostridiumbotulinum, Clostridiumtetani, Clostridiumperfringens, Clostridiumchauvoei, Clostridiumsepticum, Clostridiumnovyi and Clostridiumhemolyticum.

Emphysematous Aortitis due to Clostridium septicum in an 89-Year-Old Female with Ileus

Emphysematous aortitis is a rare but lethal form of infectious vasculitis. This condition was found incidentally on computed tomography of the chest during the evaluation of a patient presenting with pneumonia coincident with adynamic ileus. The patient did not have a history of malignancy. While colon cancer could not be ruled out, it is possible that ileus may have contributed to or resulted in bacterial translocation in this case. Appropriate investigations and empirical therapy against Clostridium septicum should be initiated in the presence of clinical and radiological findings suggestive of emphysematous aortitis.

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 β-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.

Hypervirulent Klebsiella pneumoniae

Hypervirulent K. pneumoniae (hvKp) is an evolving pathotype that is more virulent than classical K. pneumoniae (cKp). hvKp usually infects individuals from the community, who are often healthy. Infections are more common in the Asian Pacific Rim but are occurring globally. hvKp infection frequently presents at multiple sites or subsequently metastatically spreads, often requiring source control. hvKp has an increased ability to cause central nervous system infection and endophthalmitis, which require rapid recognition and site-specific treatment. The genetic factors that confer hvKp's hypervirulent phenotype are present on a large virulence plasmid and perhaps integrative conjugal elements. Increased capsule production and aerobactin production are established hvKp-specific virulence factors. Similar to cKp, hvKp strains are becoming increasingly resistant to antimicrobials via acquisition of mobile elements carrying resistance determinants, and new hvKp strains emerge when extensively drug-resistant cKp strains acquire hvKp-specific virulence determinants, resulting in nosocomial infection. Presently, clinical laboratories are unable to differentiate cKp from hvKp, but recently, several biomarkers and quantitative siderophore production have been shown to accurately predict hvKp strains, which could lead to the development of a diagnostic test for use by clinical laboratories for optimal patient care and for use in epidemiologic surveillance and research studies.

Sudden death due to gas gangrene caused by Clostridium septicum in goats

Background

Even though gas gangrene caused by Clostridium septicum in goats is mentioned in the classical textbooks, we have not managed to find any case description in the literature.

Case presentation

Clinical signs resembling gas gangrene such as subcutaneous bloating, edema and crepitation were detected at various body parts of nine pregnant animals at the ages of 2–3 years on a hair goat farm (n = 170) located in Bingol province, Eastern Turkey. Five of these suspected animals with severe clinical symptoms died within 2 days. Various samples such as internal organs, edematous skin and edema fluid collected from dead and live animals were analyzed for the presence of clostridial agents by histopathological and microbiological methods. As a result of macroscopic and microscopic examination, lesions of gas gangrene were detected. The suspected isolates were identified and confirmed as C. septicum by bacteriological and molecular methods.

Conclusion

The present study was the first to report identification of C. septicum as primary agent in the gas gangrene of goats.

Comparative efficacy of antibiotics in treating experimental Clostridium septicum infection

Clostridium septicum is a highly pathogenic microbe that causes gas gangrene in humans, and is the principal cause of spontaneous gas gangrene in patients with gastrointestinal maladies, including adenocarcinoma of the colon. Despite modern approaches to manage C. septicum infection, morbidity and mortality remain high (>60%). At present, no objective in-vivo data exist supporting the current antibiotic treatment recommendations for C. septicum infection. Utilizing an established murine model of clostridial myonecrosis, this study investigated the efficacy of standard antibiotics for anaerobic Gram-positive soft tissue infections (penicillin, clindamycin, tetracycline and vancomycin) in treating C. septicum gas gangrene. Following intramuscular challenge with 1 × 10⁶ colony-forming units of C. septicum, antibiotics were administered by intraperitoneal injection every 4 h for a total of four doses. At 30 h, all animals in all treatment groups survived the C. septicum challenge, compared with no survivors in the untreated controls (100% mortality by 10 h). However, by 60 h, mice treated with vancomycin exhibited 40% mortality, with no mortality observed in any other antibiotic treatment group. Microbroth dilution minimum inhibitory concentration analyses for three strains of C. septicum also demonstrated high susceptibility to penicillin, clindamycin and tetracycline, but considerably lower susceptibility to vancomycin. This study suggests that penicillin, clindamycin and tetracycline are suitable alternatives for the treatment of C. septicum infection in humans.

A Case of Rituximab-Induced Necrotizing Fasciitis and a Review of the Literature

Necrotizing fasciitis is a fulminant soft tissue infection characterized by rapid progression and high mortality. Rituximab is a generally well-tolerated immunosuppresive medication used for B-cell malignancies and some rheumatological disorders. We report a case of a 69-year-old male with chronic lymphocytic leukemia who suffered necrotizing fasciitis of his left lower extremity secondary to Clostridium septicum 7 weeks after treatment with rituximab. Despite immediate intravenous antimicrobial therapy and emergent fasciotomy with extensive debridement, his hospital course was complicated by septic shock and he required an above-the-knee amputation. Physicians need to be aware of the possibility of necrotizing fasciitis in patients presenting with skin infections after rituximab therapy.