Phenotyping Clostridium septicum infection: a surgeon's infectious disease

Clostridium septicum infection complicating Hemolytic-Uremic Syndrome: a case report and review of the literature

Clostridium septicum (C. septicum) is a zoonotic bacillus found in 2.8% of healthy human stools. In humans, it can cause serious infections such as bacteremia, myonecrosis, and encephalitis by spreading through the bloodstream. Reports of Shiga toxin-producing Escherichia Coli-related hemolytic-uremic syndrome complicated by C. septicum superinfection are rare, likely because colonic microangiopathic lesions by Shiga toxin-producing Escherichia Coli facilitate bacterial dissemination. Only 13 cases of Shiga toxin-producing Escherichia Coli-related hemolytic-uremic syndrome with C. septicum superinfection have been reported to date, according to our litterature review, with a 50% mortality rate. The lack of clinico-laboratory clues suggesting this condition makes the diagnosis challenging. For these reasons C. septicum superinfection usually goes undiagnosed in patients with Shiga toxin-producing Escherichia Coli-related hemolytic-uremic syndrome, and results in unfavorable outcomes. In this paper, we describe the case of a 5-year-old girl admitted for Shiga toxin-producing Escherichia Coli-related hemolytic-uremic syndrome who developed C. septicum coinfection leading to a fatal outcome. We carried out a review of the available literature on C. septicum infection complicating Shiga toxin-producing Escherichia Coli-related hemolytic-uremic syndrome and we compared the clinical features of the observed cases with those of an historical cohort of uncomplicated Shiga toxin-producing Escherichia Coli-related hemolytic-uremic syndrome. The mechanisms of superinfection are still unclear and clinical features are indistinguishable from those of uncomplicated Shiga toxin-producing Escherichia Coli-related hemolytic-uremic syndrome. However, rapid deterioration of clinical conditions and evidence of neurological involvement, associated with abnormal radiological findings, require immediate management. Although therapeutic approaches have not been directly compared, neurosurgical treatment of amenable lesions may improve the clinical outcome of patients with C. septicum-hemolytic-uremic syndrome.

Gut Microbiota in Colorectal Cancer: Biological Role and Therapeutic Opportunities

Colorectal cancer (CRC) is the second-leading cause of cancer-related deaths worldwide. While CRC is thought to be an interplay between genetic and environmental factors, several lines of evidence suggest the involvement of gut microbiota in promoting inflammation and tumor progression. Gut microbiota refer to the ~40 trillion microorganisms that inhabit the human gut. Advances in next-generation sequencing technologies and metagenomics have provided new insights into the gut microbial ecology and have helped in linking gut microbiota to CRC. Many studies carried out in humans and animal models have emphasized the role of certain gut bacteria, such as Fusobacterium nucleatum, enterotoxigenic Bacteroides fragilis, and colibactin-producing Escherichia coli, in the onset and progression of CRC. Metagenomic studies have opened up new avenues for the application of gut microbiota in the diagnosis, prevention, and treatment of CRC. This review article summarizes the role of gut microbiota in CRC development and its use as a biomarker to predict the disease and its potential therapeutic applications.

Carcinogenic microbiota and its role in colorectal cancer development

Colorectal cancer (CRC) is one of the most common malignancies worldwide. The main risk factors for CRC are family history of colon or rectal cancer, familial polyposis syndrome or hereditary nonpolyposis, and chronic inflammatory bowel diseases (ulcerative colitis and Crohn's disease). Recent studies show that the gastrointestinal microbiota play a significant role in colorectal carcinogenesis. In this review we present the microorganisms, whose influence on the development of CRC has been proven: Bacteroides fragilis, Clostridioides and Clostridium spp., Enterococcus faecalis, Escherichia coli, Fusobacterium nucleatum, Helicobacter pylori, Peptostreptococcus anaerobius, Streptococcus bovis group, and sulfate-reducing bacteria. Moreover, the carcinogenic mechanisms of action mediated by the above bacteria are laid out.

Epidemiology, aetiology and clinical characteristics of clostridial bacteraemia: a 6-year population-based observational study of 386 patients

The objective of this study is to provide a population-based clinical, epidemiological and microbiological overview of clostridial bacteraemia. All cases of bacteraemia in the Skåne Region between 2014 and 2019 with a species currently belonging to the Clostridium genus were identified in the regional clinical microbiology database. Clinical data were retrieved by medical chart-review. A total of 386 unique episodes of clostridial bacteraemia were found resulting in an incidence rate of 4.9/100.000 person-years. The median age was 76 with 56% males. The incidence rate ratio was 34.3 for those aged 80 + vs 0–59. The minimum inhibitory concentrations varied between species but were universally low for metronidazole and carbapenems. Malignancy was the most common co-morbidity, in 47% of patients and most pronounced for C. septicum. Criteria for sepsis and septic shock were met in 69% and 17%, respectively. The 28-day mortality was 26%. High age, absence of fever, high C-reactive protein and high SOFA-score were all significantly associated with mortality. We present the highest incidence rate of clostridial bacteraemia to date. Clostridial bacteraemia is a severe condition with acute onset, affecting elderly with co-morbidities, most pronounced malignancies. Mortality is related to acute manifestations rather than to background factors.

Biological roles of toll-like receptors and gut microbiota in colorectal cancer

Colorectal cancer (CRC) is one of the most considerably common malignancies of the alimentary system, with high mortality and incidence rates.  The present study suggested that the occurrence of CRC is closely related to bacteria, as the large intestine is a gathering place for human micro-organisms. However, the nosogenesis of bacteria leading to tumorigenesis is still obscure. Recently, many studies have reported that toll-like receptors and their related molecular pathways are involved in the process of gut micro-organisms generating CRC. Gut micro-organisms can promote or inhibit the development of CRC via binding to special toll-like receptors. In this paper, the authors review the relationship among toll-like receptors, gut micro-organisms and CRC in order to provide a reference for future tumor immunotherapy and targeted therapy.

Bacteria-Cancer Interface: Awaiting the Perfect Storm

Epidemiological evidence reveal a very close association of malignancies with chronic inflammation as a result of persistent bacterial infection. Recently, more studies have provided experimental evidence for an etiological role of bacterial factors disposing infected tissue towards carcinoma. When healthy cells accumulate genomic insults resulting in DNA damage, they may sustain proliferative signalling, resist apoptotic signals, evade growth suppressors, enable replicative immortality, and induce angiogenesis, thus boosting active invasion and metastasis. Moreover, these cells must be able to deregulate cellular energetics and have the ability to evade immune destruction. How bacterial infection leads to mutations and enriches a tumour-promoting inflammatory response or micro-environment is still not clear. In this review we showcase well-studied bacteria and their virulence factors that are tightly associated with carcinoma and the various mechanisms and pathways that could have carcinogenic properties.

Concurrent Clostridium septicum bacteremia and colorectal adenocarcinoma with metastasis to the brain - A Case Report

There is a known relationship between Clostridium septicum bacteremia and colorectal malignancies. C. septicum is a gram-positive, anaerobic, spore-forming bacterium that can survive the acidic colorectal tumor microenvironment, where it is thought to enter the blood by tumor-mediated epithelial tissue damage. While in circulation, C. septicum can release exotoxins which may lead to life-threatening sepsis. The patient in this case presented with a mild fever, abdominal pain, and left hand weakness. Imaging of the head and abdomen revealed a right frontal lucency and wall thickening of the ascending colon. Two colonic adenocarcinomas were found and removed via an exploratory laparotomy and right hemicolectomy. The blood culture was positive for C. septicum. Brain MRI confirmed a right frontal mass concerning for metastasis. Here, we discuss the relationship between colonic cancers and Clostridium septicum bacteremia.

Clostridium septicum endophthalmitis as the first manifestation of a colon adenocarcinoma: A case report

Clostridium septicum endophthalmitis is an extremely rare infection with only a few cases reported in the literature. It has an endogenous origin and is associated with gastrointestinal and haematological malignancies. We present the case of a 62-year-old male who presented this infection as the first manifestation of a colon adenocarcinoma.

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.

Diarrhea Predominant-Irritable Bowel Syndrome (IBS-D): Effects of Different Nutritional Patterns on Intestinal Dysbiosis and Symptoms

Irritable Bowel Syndrome (IBS) is a chronic functional gastrointestinal disorder characterized by abdominal pain associated with defecation or a change in bowel habits. Gut microbiota, which acts as a real organ with well-defined functions, is in a mutualistic relationship with the host, harvesting additional energy and nutrients from the diet and protecting the host from pathogens; specific alterations in its composition seem to play a crucial role in IBS pathophysiology. It is well known that diet can significantly modulate the intestinal microbiota profile but it is less known how different nutritional approach effective in IBS patients, such as the low-FODMAP diet, could be responsible of intestinal microbiota changes, thus influencing the presence of gastrointestinal (GI) symptoms. The aim of this review was to explore the effects of different nutritional protocols (e.g., traditional nutritional advice, low-FODMAP diet, gluten-free diet, etc.) on IBS-D symptoms and on intestinal microbiota variations in both IBS-D patients and healthy subjects. To date, an ideal nutritional protocol does not exist for IBS-D patients but it seems crucial to consider the effect of the different nutritional approaches on the intestinal microbiota composition to better define an efficient strategy to manage this functional disorder.

Microbial Characteristics of Locally Advanced Rectal Cancer Patients After Neoadjuvant Chemoradiation Therapy According to Pathologic Response

Background

Intestinal microbiota play a critical role in the development of colorectal cancer. However, little is known about the structure and characteristics of gut microbial in colorectal cancer, especially in locally advanced rectal cancer after neoadjuvant chemoradiation therapy.

Methods

Here, we performed this study to evaluate microbial characteristics between pathologic complete response (pCR) (n=12) and non-pathological complete response (Non-pCR) (n=45) tumor tissues from patients with locally advanced rectal cancer after neoadjuvant chemoradiation therapy. In this study, 16S rRNA gene sequencing was used to detect the microbial diversity including Alpha diversity and Beta diversity. Moreover, we used PICRUSt from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database to predict the microbial metabolism functions.

Results

There was significant statistical difference in PFS between pCR and Non-pCR group (p < 0.05). However, there was no significant difference in OS between pCR and Non-pCR group. The microbial compositions in the both groups were Proteobacteria, Actinobacteria, Firmicutes and Thermi and Bacteroidetes at the phylum level. The five most predominant genera in both pCR and Non-pCR tissue groups were Sphingobium, Acinetobacter, Cupriavidus, Thermi and Sphingomonas at the genus level. The key taxa identified in the pCR and Non-pCR tissues were Thermi and Sphingomonadaceae respectively. In addition, a series of human disease-related genes were also significantly different between pCR and Non-pCR group.

Conclusion

In summary, we demonstrated the characteristic differences in microbial communities between pCR tissues and Non-pCR tumor tissues from locally advanced rectal cancer patients after neoadjuvant chemoradiation therapy. Our results present new alterations in the microbiome in locally advanced rectal cancer after neoadjuvant chemoradiation therapy, suggesting that it will provide a new perspective for the precise treatment of neoadjuvant rectal cancer by targeting specific microbial species in the future.

The Role of Hyperbaric Oxygen Therapy in Pneumatosis Cystoides Intestinalis-A Scoping Review

Pneumatosis cystoides intestinalis (PCI) is characterized by gas-filled cysts within gastrointestinal tract wall from esophagus to rectum, with preferential involvement of large and small intestine. PCI is rare with an estimated incidence of 0.03 to 0-2% in general population. PCI can be distinguished into idiopathic (15%) or secondary (85%) and the clinical picture ranges from completely asymptomatic to life-threatening intraabdominal complications. Although etiology of PCI appears to be multifactorial, the exact pathophysiology is poorly understood and two main theories have been proposed (mechanical and bacterial). Over the last decades, an enormous therapeutic armamentarium was considered in PCI's management, including hyperbaric oxygen therapy (HBOT). Treatment comprises conservative treatment in mild cases to surgery in highly symptomatic and complicated PCI. In the late 70s, HBOT started to be used in selected cases of PCI not responding to conservative measures. Since then, several case reports, case series, and reviews have been published in the literature with variable outcomes. The overall response rate and complete response were 92.1% (n = 82/89) and 65.2% (n = 58/89), respectively, with a median follow-up of 7 months. Furthermore, HBOT is extremely safe, with few reported complications in the literature when used for PCI. Nevertheless, a randomized, controlled, and double-blind clinical trial is unlikely to occur given the rarity of PCI, logistical issues of HBOT, and methodological considerations related to adequate blinding with a sham-controlled group. HBOT in combination with personalized diet and antibiotics may be beneficial for moderate to severe PCI in patients with no indication for emergency exploratory laparotomy. The purpose of this article is to synthesize the existing data, analyse results of previous studies, identify gaps in knowledge, and discuss PCI' management, including the proposal of an algorithm, with a special focus on HBOT.

Early Detection of Colon Cancer Following Incidental Finding of Clostridium septicum Bacteremia

Clostridium septicum is a Gram-positive, anaerobic, spore-forming bacillus found in the intestine. It is linked to colon cancer and immunosuppression. Infection with C septicum may vary in manifestation and is associated with more than 60% mortality rate. In this article, we present a case of incidental isolation of C septicum in a patient who presented with fever and later on colonoscopy was found to have colon carcinoma. Bacteremia may be the unexpected initial presentation of undiagnosed colon carcinoma.

Distinct Microbial Populations Exist in the Mucosa-associated Microbiota of Diarrhea Predominant Irritable Bowel Syndrome and Ulcerative Colitis

GOALS

The goal of this study was to observe the bacterial colonization in the intestinal mucosa in the patients with diarrhea predominant irritable bowel syndrome (IBS-D) and ulcerative colitis (UC), and compare the mucosa-associated microbiota among the IBS-D patients, UC patients and the healthy control, and explore the correlation of the mucosa-associated microbiota with clinical manifestations.

STUDY

A total of 20 IBS-D patients, 28 patients with UC (16 active, 12 inactive) and 16 healthy subjects were enrolled in the study. They all underwent colonoscopies in the Gastrointestinal Endoscopy Center in the Second Affiliated Hospital of Xi'an Jiaotong University from June 2016 to October 2016. The mucosa specimens were taken at the junction of rectum and sigmoid colon for fluorescent in situ hybridization (FISH). Then the observed mucosa-associated microbiota was counted and compared.

RESULTS

(1) In the IBS-D patients, the mucosa-associated bacteria were found to colonize in the surface of mucosa and the adjacent mucin layer. And in active UC, Escherichia coli, and Bacteroides were found in the lamina propria, in addition to bacterial colonization in the above-mentioned areas. (2) The total count of mucosa-associated bacteria and the individual counts of E. coli, Clostridium, and Bacteroides were significantly increased, and Bifidobacteria significantly decreased (P<0.05) in the IBS-D patients and UC patients. Counts of Lactobacillus were decreased only in UC patients compared with the healthy control. And a significantly larger variation of the above-mentioned bacterial counts was found in the patients with UC, particularly in those with active UC, compared with those with IBS-D (P<0.05); the counts in the UC group were 1.3 to 5.3 times more or less than those in the IBS-D group. (3) Compared with healthy controls and IBS-D, the total count of bacteria and the individual counts of E. coli and Bacteroides in the lamina propria in active UC were significantly increased (P<0.05). (4) A significant negative correlation of the counts of Lactobacillus and Bifidobacteria with the defecation frequency and fecal characteristics (P<0.05) was found in the IBS-D patients; in those with UC, both the total count of bacteria and the individual counts of E. coli, Clostridium, Bacteroides, Lactobacillus, and Bifidobacteria were significantly correlated, positively or negatively, with the related clinical manifestations and the activity of the disease (P<0.05).

CONCLUSIONS

Compared with the healthy control, intestinal microecology was changed most obviously in UC with much smaller differences though in the same direction in IBS-D. The translocation of some bacteria into the lamina propria was found in UC, particularly in active UC. The changes of mucosa-associated microbiota were related more or less to some clinical manifestations in IBS-D and UC.

Probable Clostridium septicum pneumocephalus in a user of natural remedies with newly diagnosed diabetes mellitus type 1

Clostridium septicum encephalitis is a rare cause of spontaneous, non-traumatic pneumocephalus. Systemic infections with this organism have a fulminant course, likely leading to death within 48 hours, and are commonly associated with hematological or colonic malignancies. The effectiveness of an antibacterial regimen is unknown because of a lack of studies. The best prognosis is observed in patients undergoing early surgical intervention for localized intracranial processes. Here we describe a case of rapidly developing C. septicum sepsis as a result of bacteremia and hematogenous spread, resulting in encephalitis and pneumocephalus in a patient without a diagnosed malignancy. The patient presented to the emergency department with diabetic ketoacidosis, which led to the diagnosis of new-onset type 1 diabetes mellitus. There are currently 19 reported cases of C. septicum central nervous system infections in the literature, with 12 of them having pneumocephalus. Natural remedies, such as drinking kombucha tea and performing coffee enemas, that were used by our patient may have played a role in the dissemination of C. septicum. In survivors of this fulminant illness, colonic and hematologic malignancies should be excluded because of their association with such infections. Type 1 diabetes mellitus, drinking kombucha tea, and performing coffee enemas may be newly recognized risk factors associated with the dissemination of C. septicum.

Exploring the microbiota to better understand gastrointestinal cancers physiology

Gastrointestinal cancers account for around 40% of cancer-related deaths worldwide, representing a global health burden. There is a growing body of evidence highlighting the link between microbiota and gastrointestinal tumorigenesis and/or resistance to therapy. In the present manuscript, we reviewed the published studies on the relationship between the microbiota and the different gastrointestinal tumors, namely, gastric, colorectal and esophageal, including also the cancer of accessory organs such as liver and pancreas. There is an emergent interest in the manipulation of gastrointestinal microflora in order to understand the gastrointestinal tumorigenesis' processes and the establishment of chemoresistance mechanisms.

Clostridium septicum arthroplasty infection: beware of occult aortitis and malignancy

Introduction

The Clostridia species are responsible for life-threatening conditions such as tetanus, botulism and gas gangrene. Clostridium septicum is a rare cause of clinical infection, accounting for less than 1% of blood culture samples that test positive for Clostridia. However, C. septicum bacteraemia is associated with greater than 60% mortality and in over 80% of cases is associated with an underlying malignancy.

Case presentation

We present a review of the literature and the first case of an acute arthroplasty infection and concurrent infective aortitis caused by this organism in the absence of an identified underlying malignancy. Early diagnosis and multi-disciplinary input resulted in the patient surviving a rare and potentially fatal infective aortitis and septic arthritis.

Conclusion

This case demonstrates the importance of early systemic investigation to exclude occult infective aortitis in C. septicum infection. The key role of multi-disciplinary input into the management of this often fatal infection is also discussed along with the requirement to exclude occult gastrointestinal and haematological malignancy.

Inflammatory and infectious manifestations of immunodeficiency in the gastrointestinal tract

Immune compromise may result from genetic abnormalities, HIV/AIDS, or consequences of therapy for neoplastic and autoimmune diseases. Many immunocompromised patients develop severe gastrointestinal symptoms, particularly diarrhea, accompanied by non-specific or mild endoscopic abnormalities; mucosal biopsy with pathologic interpretation has a major role in the diagnosis and management of these patients. Immunocompromised individuals are at risk for all the diseases that affect those with a healthy immune system, but they are also prone to other illnesses that rarely affect immunocompetent patients. This review discusses the gastrointestinal manifestations of primary and acquired immunodeficiency, chemotherapy-related injury, and infections that show a predilection for immunocompromised patients. Key histologic features and relevant differential diagnoses are emphasized.

Spontaneous C. septicum gas gangrene: A literature review

As the infectious disease paradigm undergoes a subtle shift, unusual infections associated with malignancy and immunosuppression are being increasingly reported. Spontaneous or non-traumatic Clostridium septicum infection is one such unusual infection which has gained prominence. This article aims to understand the pathophysiology, clinical manifestations and current trends in diagnosing and treating this rare but deadly infection. To understand the multifactorial causation of this infection a review of published cases of spontaneous C. septicum gas gangrene was performed and a total of 94 such cases were identified. Several factors were analyzed for each case: age, infection location and underlying illness, presenting signs and symptoms, neutropenia, gross pathology of the colon, antibiotic use, surgical intervention, and survival. A known or occult malignancy was present in 71% patients and an overall mortality of 67% was observed.

Colorectal neoplasm in cases of Clostridium septicum and Streptococcus gallolyticus subsp. gallolyticus bacteraemia

BACKGROUND

Bacteremia with Clostridium septicum (CS) and Streptococcus gallolyticus subsp. gallolyticus (SGG) have both been associated with colorectal neoplasms (CRN) and colonoscopic examination is advised, however the differences and similarities in colorectal findings are not well known.

METHODS

This is a multicenter, comparative study of patients with CS bacteremia [44 of 664 cases (6.6%) of Clostridium spp.] and SGG bacteremia [257 of 596 cases (44.2%) of S. bovis group], carried out in three hospitals from Spain. Clinical findings related to bacteremia and associated CRN were collected.

RESULTS

The main sources of infection were abdominal (77.7%) for CS bacteremia and endovascular (75%) for SGG bacteremia. CS bacteremia was more often associated with malignancies, (72.6% vs. 19.4%) and neutropenia (29.5% vs. 3.1%), and was more acute, with shock at presentation (63.6% vs. 3.9%) and higher 30-day mortality (47.7% vs. 9.7%) compared to SGG (P<0.05 for all). Both, patients with CS and SGG bacteremia often had concomitant CRN (43.1% vs. 49.8%) and most of them presented as occult CRN (73.7% vs. 91.4%; P=0.02). CS cases more often had invasive carcinomas (94.7% vs. 19.5%), location of CRN in the right colon (73.7% vs. 23.4%), larger tumor size (median 7 vs. 1.5cm), and a higher overall CRN related mortality rate (68.4% vs. 7.8%) compared to SGG cases (P<0.05 for all).

CONCLUSIONS

Both, CS and SGG bacteremia are associated with occult CRN. CS cases more often had advanced carcinomas than SGG cases, suggesting a distinct temporal association with CRN.

C septicum Complicating Hemolytic Uremic Syndrome: Survival Without Surgical Intervention

Clostridium septicum is an anaerobic bacterium that causes rapidly progressive myonecrosis, bacteremia, and central nervous system infection. It has been reported as a complication of Escherichia coli hemolytic uremic syndrome (HUS) in 8 children worldwide; 5 children died, and the 3 reported survivors had surgically treated disease. We present 3 cases of C septicum complicating HUS in children, including the first 2 reported cases of survival without surgical intervention. All patients presented with classic cases of HUS with initial clinical improvement followed by deterioration. Patient 1 had rising fever, tachycardia, and severe abdominal pain 24 hours after admission. She developed large multifocal intraparenchymal cerebral hemorrhages and died 12 hours later. Autopsy revealed C septicum intestinal necrosis, myonecrosis, and encephalitis. Patient 2 had new fever, increasing leukocytosis, and severe abdominal pain on hospital day 4. She was diagnosed with C septicum bacteremia and treated with metronidazole, meropenem, and clindamycin. Patient 3 had new fever and increasing leukocytosis on hospital day 3; blood cultures grew C septicum, and she was treated with penicillin. Patients 2 and 3 improved rapidly and did not require surgery. C septicum is a potential co-infection with E coli It thrives in the anaerobic environment of E coli-damaged intestinal mucosa and translocates to cause systemic infection. Fever, tachycardia, a rising white blood cell count, and abdominal pain out of proportion to examination are key findings for which physicians should be vigilant. Timely evaluation by anaerobic blood culture and early initiation of antibiotics are necessary to prevent fatalities.

Gut microbiota imbalance and colorectal cancer

The gut microbiota acts as a real organ. The symbiotic interactions between resident micro-organisms and the digestive tract highly contribute to maintain the gut homeostasis. However, alterations to the microbiome caused by environmental changes (e.g., infection, diet and/or lifestyle) can disturb this symbiotic relationship and promote disease, such as inflammatory bowel diseases and cancer. Colorectal cancer is a complex association of tumoral cells, non-neoplastic cells and a large amount of micro-organisms, and the involvement of the microbiota in colorectal carcinogenesis is becoming increasingly clear. Indeed, many changes in the bacterial composition of the gut microbiota have been reported in colorectal cancer, suggesting a major role of dysbiosis in colorectal carcinogenesis. Some bacterial species have been identified and suspected to play a role in colorectal carcinogenesis, such as Streptococcus bovis, Helicobacter pylori, Bacteroides fragilis, Enterococcus faecalis, Clostridium septicum, Fusobacterium spp. and Escherichia coli. The potential pro-carcinogenic effects of these bacteria are now better understood. In this review, we discuss the possible links between the bacterial microbiota and colorectal carcinogenesis, focusing on dysbiosis and the potential pro-carcinogenic properties of bacteria, such as genotoxicity and other virulence factors, inflammation, host defenses modulation, bacterial-derived metabolism, oxidative stress and anti-oxidative defenses modulation. We lastly describe how bacterial microbiota modifications could represent novel prognosis markers and/or targets for innovative therapeutic strategies.

Fatal Spontaneous Clostridium septicum Gas Gangrene: A Possible Association With Iatrogenic Gastric Acid Suppression

The long-term use of proton pump inhibitors has been linked to an increased risk for the development of gastric polyps, hip fractures, pneumonia, and Clostridium difficile colitis. There is evidence that chronic acid suppression from long-term use of proton pump inhibitors poses some risk for the development of C difficile–associated diarrhea by decreasing the elimination of pathogenic microbes before reaching the lower gastrointestinal tract. Here we present a case of a 51-year-old woman with a recent history of abdominal pain and fever who presented to the emergency department with rapidly progressive spontaneous necrotizing fasciitis and gas gangrene and died within hours of presentation. Postmortem examination confirmed spreading tissue gas gangrene and myonecrosis. In addition, multiple intestinal ulcers containing Clostridium septicum were present at autopsy. This case illustrates a possible association between proton pump inhibitor therapy and fatal C septicum infection.

Gut bacteria in health and disease: a survey on the interface between intestinal microbiology and colorectal cancer

A healthy human body contains at least tenfold more bacterial cells than human cells and the most abundant and diverse microbial community resides in the intestinal tract. Intestinal health is not only maintained by the human intestine itself and by dietary factors, but is also largely supported by this resident microbial community. Conversely, however, a large body of evidence supports a relationship between bacteria, bacterial activities and human colorectal cancer. Symbiosis in this multifaceted organ is thus crucial to maintain a healthy balance within the host-diet-microbiota triangle and accordingly, changes in any of these three factors may drive a healthy situation into a state of disease. In this review, the factors that sustain health or drive this complex intestinal system into dysbiosis are discussed. Emphasis is on the role of the intestinal microbiota and related mechanisms that can drive the initiation and progression of sporadic colorectal cancer (CRC). These mechanisms comprise the induction of pro-inflammatory and pro-carcinogenic pathways in epithelial cells as well as the production of (geno)toxins and the conversion of pro-carcinogenic dietary factors into carcinogens. A thorough understanding of these processes will provide leads for future research and may ultimately aid in development of new strategies for CRC diagnosis and prevention.

Simultaneous necrotizing soft tissue infection and colonic necrosis caused by Clostridium septicum

BACKGROUND

Clostridial myonecrosis is an uncommon, highly lethal necrotizing soft tissue infection. The source may be occult at the time of clinical presentation. In cases caused by Clostridium septicum, there is an association with colorectal malignant disease, suggesting that underlying colonic pathology frequently is the source of the infection.

METHODS

Case report and literature review.

CASE REPORT

A 37-year old man with acquired immunodeficiency syndrome, end-stage renal disease, and C. difficile colitis presented to the Emergency Department (ED) with a primary complaint of abdominal pain and incidental right forearm pain. While undergoing evaluation in the ED, he developed progressive erythema, edema, and emergence of bullae over his right forearm. After rapid imaging of his abdomen, he underwent guillotine amputation of his right upper extremity because of extensive myonecrosis and total abdominal colectomy secondary to right colonic necrosis and C. difficile colitis. Blood cultures were positive for C. septicum. Microscopic examination of both the necrotic colon and the right forearm musculature demonstrated invasion of gram-positive bacilli throughout.

CONCLUSIONS

Myonecrosis caused by C. septicum frequently occurs in the presence of colonic pathology, typically malignant disease. This case report illustrates the development of this pathological process in an immunosuppressed patient who did not have colon cancer, but rather colonic mucosal inflammation produced by C. difficile.

Clostridium septicum Sepsis and Colon Carcinoma: Report of 4 Cases

An association exists between colon carcinoma and Clostridium septicum infection, especially bacteremia. We reviewed retrospectively all positive blood cultures for this organism at a 300-bed general hospital over 4 years. Four of 15 cases were associated with concurrent colon carcinoma. C. septicum infection was the presenting feature of previously undiagnosed large bowel malignancy in three patients. We report this small case series to alert clinicians to the diverse spectrum and diagnostic difficulties of this rare, potentially catastrophic association. Although commonly associated with necrotizing skin or soft tissue infections, this bacterium can present with nonspecific or atypical symptoms. All patients with positive blood cultures for C. septicum, even without clinical suspicion of large bowel malignancy, should undergo colonoscopy to evaluate for colon carcinoma.

Spore-forming Bacilli and Clostridia in human disease

Many Gram-positive spore-forming bacteria in the Firmicute phylum are important members of the human commensal microbiota, which, in rare cases, cause opportunistic infections. Other spore-formers, however, have evolved to become dedicated pathogens that can cause a striking variety of diseases. Despite variations in disease presentation, the etiologic agent is often the spore, with bacterially produced toxins playing a central role in the pathophysiology of infection. This review will focus on the specific diseases caused by spores of the Clostridia and Bacilli.

Sepsis and gas-forming splenic abscess by Clostridium septicum in a patient with type 2 diabetes

Clostridium infections are rare but frequently associated with malignancy, and mortality approaches 100% if care is not rendered within 12 to 24 h. These infections are associated with various medical problems including diabetes mellitus. In this report, we describe a unique case of sepsis and a gas-forming splenic abscess caused by Clostridium septicum in a type 2 diabetes patient which was treatable solely with antibiotics.

Clostridium septicum necrotizing fasciitis of the forefoot secondary to adenocarcinoma of the colon: Case report and review of the literature

Clostridium septicum accounts for 1% of all reported clostridial infections. C septicum infections are most often nontraumatic in nature and associated with either an occult colonic or hematologic malignancy. The initial presentation of a C septicum infection can be relatively benign with rapid progression to fatality without emergent treatment. Presented is a case of necrotizing fasciitis of the forefoot caused by C septicum associated with an occult adenocarcinoma of the colon in a patient with uncontrolled diabetes. The process we used to achieve successful functional limb preservation based on rapid surgical intervention and use of a multidisciplinary approach to medical and surgical management of this patient is discussed in detail, as well as a through review of the literature regarding the association between malignancies and C septicum infections.

Programmed cellular necrosis mediated by the pore-forming alpha-toxin from Clostridium septicum

Programmed necrosis is a mechanism of cell death that has been described for neuronal excitotoxicity and ischemia/reperfusion injury, but has not been extensively studied in the context of exposure to bacterial exotoxins. The α-toxin of Clostridium septicum is a β-barrel pore-forming toxin and a potent cytotoxin; however, the mechanism by which it induces cell death has not been elucidated in detail. We report that α-toxin formed Ca²⁺-permeable pores in murine myoblast cells, leading to an increase in intracellular Ca²⁺ levels. This Ca²⁺ influx did not induce apoptosis, as has been described for other small pore-forming toxins, but a cascade of events consistent with programmed necrosis. Ca²⁺ influx was associated with calpain activation and release of cathepsins from lysosomes. We also observed deregulation of mitochondrial activity, leading to increased ROS levels, and dramatically reduced levels of ATP. Finally, the immunostimulatory histone binding protein HMGB1 was found to be released from the nuclei of α-toxin-treated cells. Collectively, these data show that α-toxin initiates a multifaceted necrotic cell death response that is consistent with its essential role in C. septicum-mediated myonecrosis and sepsis. We postulate that cellular intoxication with pore-forming toxins may be a major mechanism by which programmed necrosis is induced.

Clostridium septicum is a highly virulent pathogen that causes spontaneous gas gangrene or clostridial myonecrosis. The essential virulence factor of C. septicum is a β-barrel toxin, α-toxin, that forms small pores in host cell membranes. This toxin is frequently described as a hemolysin, because the formation of these pores causes lysis of red blood cell cells due to membrane disruption. However, this description does not recognize additional effects that may be observed in nucleated host cells, which are more sensitive to α-toxin. We investigated how nucleated cells responded to α-toxin by treating a physiologically relevant muscle cell line with purified toxin and monitoring the response using various assays. We observed α-toxin-mediated programmed cellular necrosis that culminated in the release of the immunostimulatory molecule, HMGB1. This mechanism of cell death induction is consistent with the extensive necrosis that is evident in C. septicum-mediated myonecrosis and with the overwhelming sepsis that frequently contributes to the high mortality rate. These results represent an important advance in the understanding of the toxicity of β-barrel pore-forming toxins and how they may contribute to necrotic and systemic disease pathology.