Unusual bacterial infections and colorectal carcinoma--Streptococcus bovis and Clostridium septicum: report of three cases

Characterization of TelE, a T7SS LXG Effector Exhibiting a Conserved C-Terminal Glycine Zipper Motif Required for Toxicity

Streptococcus gallolyticus subsp. gallolyticus (SGG) is an opportunistic bacterial pathogen strongly associated with colorectal cancer. Here, through comparative genomics analysis, we demonstrated that the genetic locus encoding the type VIIb secretion system (T7SSb) machinery is uniquely present in SGG in two different arrangements. SGG UCN34 carrying the most prevalent T7SSb genetic arrangement was chosen as the reference strain. To identify the effectors secreted by this secretion system, we inactivated the essC gene encoding the motor of this machinery. A comparison of the proteins secreted by UCN34 wild type and its isogenic ΔessC mutant revealed six T7SSb effector proteins, including the expected WXG effector EsxA and three LXG-containing proteins. In this work, we characterized an LXG-family toxin named herein TelE promoting the loss of membrane integrity. Seven homologs of TelE harboring a conserved glycine zipper motif at the C terminus were identified in different SGG isolates. Scanning mutagenesis of this motif showed that the glycine residue at position 470 was crucial for TelE membrane destabilization activity. TelE activity was antagonized by a small protein TipE belonging to the DUF5085 family. Overall, we report herein a unique SGG T7SSb effector exhibiting a toxic activity against nonimmune bacteria. IMPORTANCE In this study, 38 clinical isolates of Streptococcus gallolyticus subsp. gallolyticus (SGG) were sequenced and a genetic locus encoding the type VIIb secretion system (T7SSb) was found conserved and absent from 16 genomes of the closely related S. gallolyticus subsp. pasteurianus (SGP). The T7SSb is a bona fide pathogenicity island. Here, we report that the model organism SGG strain UCN34 secretes six T7SSb effectors. One of the six effectors named TelE displayed a strong toxicity when overexpressed in Escherichia coli. Our results indicate that TelE is probably a pore-forming toxin whose activity can be antagonized by a specific immunity protein named TipE. Overall, we report a unique toxin-immunity protein pair and our data expand the range of effectors secreted through T7SSb.

Host microbiomes in tumor precision medicine: how far are we?

The human gut microbiome has received a crescendo of attention in recent years, due to the countless influences on human pathophysiology, including cancer. Research on cancer and anticancer therapy is constantly looking for new hints to improve the response to therapy while reducing the risk of relapse. In this scenario, the gut microbiome and the plethora of microbial-derived metabolites are considered a new opening in the development of innovative anticancer treatments for a better prognosis. This narrative review summarizes the current knowledge on the role of the gut microbiome in the onset and progression of cancer, as well as in response to chemo-immunotherapy. Recent findings regarding the tumor microbiome and its implications for clinical practice are also commented on. Current microbiome-based intervention strategies (i.e., prebiotics, probiotics, live biotherapeutics and fecal microbiota transplantation) are then discussed, along with key shortcomings, including a lack of long-term safety information in patients who are already severely compromised by standard treatments. The implementation of bioinformatic tools applied to microbiomics and other omics data, such as machine learning, has an enormous potential to push research in the field, enabling the prediction of health risk and therapeutic outcomes, for a truly personalized precision medicine.

Strategies for the treatment of colorectal cancer caused by gut microbiota

Colorectal cancer (CRC), also named as colon and rectal or bowel cancer, is one of the leading neoplasia diagnosed in the world. Genetic sequencing studies of microorganisms from the intestinal microbiota of patients with CRC revealed that changes in its composition occur with the development of the disease, which can play a fundamental role in its development, being mediated by the production of metabolites and toxins that damage enterocytes. Some microorganisms are frequently reported in the literature as the main agents of this process, such as the bacteria Fusobacterium nucleatum, Escherichia coli and Bacteroides fragilis. Thus, understanding the mechanisms and function of each microorganism in CRC is essential for the development of treatment tools that focus on the gut microbiota. This review verifies current research aimed at evaluating the microorganisms present in the microbiota that can influence the development of CRC, as well as possible forms of treatment that can prevent the initiation and/or spread of this disease. Due to the incidence of CRC, alternatives have been launched considering factors beyond those already known in the disease development, such as diet, fecal microbiota transplantation, use of probiotics and antibiotics, which have been widely studied for this purpose. However, despite being promising, the studies that focus on the development of new therapeutic approaches targeting the microorganisms that cause CRC still need to be improved and better developed, involving new techniques to elucidate the effectiveness and safety of these new methods.

Growth rate alterations of human colorectal cancer cells by 157 gut bacteria

Several bacteria in the human gut microbiome have been associated with colorectal cancer (CRC) by high-throughput screens. In some cases, molecular mechanisms have been elucidated that drive tumorigenesis, including bacterial membrane proteins or secreted molecules that interact with the human cancer cells. For most gut bacteria, however, it remains unknown if they enhance or inhibit cancer cell growth. Here, we screened bacteria-free supernatants (secretomes) and inactivated cells of over 150 cultured bacterial strains for their effects on cell growth. We observed family-level and strain-level effects that often differed between bacterial cells and secretomes, suggesting that different molecular mechanisms are at play. Secretomes of Bacteroidaceae, Enterobacteriaceae, and Erysipelotrichaceae bacteria enhanced cell growth, while most Fusobacteriaceae cells and secretomes inhibited growth, contrasting prior findings. In some bacteria, the presence of specific functional genes was associated with cell growth rates, including the virulence genes TcdA, TcdB in Clostridiales and FadA in Fusobacteriaceae, which both inhibited growth. Bacteroidaceae cells that enhanced growth were enriched for genes of the cobalamin synthesis pathway, while Fusobacteriaceae cells that inhibit growth were enriched for genes of the ethanolamine utilization pathway. Together, our results reveal how different gut bacteria have wide-ranging effects on cell growth, contribute a better understanding of the effects of the gut microbiome on host cells, and provide a valuable resource for identifying candidate target genes for potential microbiome-based diagnostics and treatment strategies.

Progress in Research on Colorectal Cancer-Related Microorganisms and Metabolites

Intestinal flora is an important component in the human body, which have been reported to be involved in the occurrence and development of colorectal cancer (CRC). Indeed, changes in the intestinal flora in CRC patients compared to those in control subjects have been reported. Several bacterial species have been shown to exhibit the pro-inflammatory and pro-carcinogenic properties, which could consequently have an impact on colorectal carcinogenesis. In this review, we summarize the current knowledge on the potential links between the intestinal microbiota and CRC. We illustrated the mechanisms by which intestinal flora imbalance affects CRC, mainly focusing on inflammation, microbial metabolites, and specific bacteria species. In addition, we discuss how a diet exhibits a strong impact on microbial composition and provides risks for developing CRC. Finally, we describe the potential future directions that are based on intestinal microbiota manipulation for CRC diagnosis and treatment.

Isolated spontaneous biceps abscess causing septic shock in a diabetic patient: A rare case report

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Intramuscular abscesses, particularly in the biceps brachii, are very rare.

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The majority are associated with haematoma secondary to trauma, intramuscular injections, or systemic disease.

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If untreated, it can rapidly lead to septic shock and involvement of surrounding joints.

Introduction

Intramuscular abscesses, particularly in the biceps brachii, are an extremely rare phenomenon. When present they are usually secondary to trauma, intramuscular injections, or systemic disease.

Presentation of case

A 56 year old diabetic woman presented to our emergency department with a 3 day history of fever, cough, and a painful left shoulder. Although she had a mechanical fall 2 weeks prior, she denied any pain in her shoulder immediately after the fall. She also denied any history of drug abuse or recent intramuscular injection. On examination she looked acutely unwell and was in acute septic shock requiring inotropic support. Computed tomography of her shoulder showed a large intramuscular abscess in her left biceps brachii muscle. She was immediately taken to the operating theatre for open exploration and washout of the abscess. The multiloculated abscess was tracking into the glenohumeral joint. Post operatively she showed significant clinical improvement and after a 2 week course of intravenous antibiotics recovered well and was discharged from hospital.

Discussion

Intramuscular abscesses are usually seen in patients who are immunocompromised. Intramuscular needle injections and haematomas secondary to trauma are also risk factors. To the best of our knowledge, there have only been 4 published reports in the English literature of intramuscular abscess formation in the biceps brachii.

Conclusion

We report a case of a seemingly spontaneous intramuscular biceps abscess in a diabetic patient presenting with septic shock.

Study Insights into Gastrointestinal Cancer through the Gut Microbiota

The gut microbiome in human is recognized as a “microbial organ” for its roles and contributions in regulating the human homeostasis and metabolism. Gastrointestinal (GI) cancers, especially colorectal cancer (CRC), rank as the most common cancer-related deaths worldwide. Evidences have suggested that the disorder of gut microbiota, also named as “dysbiosis,” is related to the development of a variety of diseases such as inflammatory bowel disease (IBD) and the CRC. However, detailed mechanisms between disease and gut microbiota remain largely unknown. This review introduced the correlation between gastrointestinal diseases and the microbiota in human gut from the recent studies, as well as the roles of microbiota in manipulating the CRC and IBDs development, in order to facilitate future studies and to develop novel methods for the precaution, diagnosis, or even cure of gastrointestinal diseases. Additionally, we also elucidated the possibility of probiotics in treatment against CRC.

A case of silent colonic lesions associated with streptococcus gallolyticus, bacteremia and endocarditis

We present a clinical case of synchronous colonic lesions, histologically different, associated with streptococcus gallolyticus subsp. gallolyticus (Sgg)/ Streptococcus bovis biotype I, bacteremia and infective endocarditis. A 53-year-old female, without history of CRC in her family, known with total hysterectomy for uterine fibromatosis, presents to Emergency Department for marked asthenia, nausea, weight loss (10 kgs in the last month), febrile episode associated with severe anemia, symptomatology that has increased in the last two weeks. The patient was admitted in the Internal Medicine Department for further investigations, under the suspicion of sepsis of unknown cause. On blood cultures grew Sgg bacteria. Both transthoracic echocardiography and transesophageal echocardiography were performed and diagnosed infective endocarditis with vegetations of the mitral and aortic valves. Antibiotics treatment was initiated, with ceftriaxone and gentamycin, according to antibiogram results. Severe hypochromic, microcytic anemia, and lack of an infective origin site required digestive endoscopic evaluation, and showed gastritis, ulcerovegetative tumor of the ascending colon and polyp in the rectosigmoid. Resection of rectosigmoid polyp was performed through colonoscopy, and, also, right hemicolectomy with ileo-transverse anastomosis for the ascending colon cancer. Post-operative evolution was favorable. Histological result showed mucinous adenocarcinoma of the ascending colon and tubulovillous adenoma, with moderate dysplasia, in the rectosigmoid. At 6-month, endoscopic evaluation showed normal aspect of anastomosis without presence of other colonic lesions.

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.

Gut microbiota, inflammation and colorectal cancer

Although genes contribute to colorectal cancer, the gut microbiota are an important player. Accumulating evidence suggests that chronic infection and the ensuing inflammation contributes to tumor initiation and tumor progression. A variety of bacterial species and tumor-promoting virulence mechanisms have been investigated. Significant advances have been made in understanding the composition and functional capabilities of the gut microbiota and its roles in cancer. In the current review, we discuss the novel roles of microbiota in the progression of colon cancer. Although microbiota technically include organisms other than bacteria e.g., viruses and fungi, this review will primarily focus on bacteria. We summarize epidemiological studies of human microbiome and colon cancer. We discuss the progress in the scientific understanding of the interplay between the gut microbiota, barrier function, and host responses in experimental models. Further, we discuss the potential application in prevention, diagnosis, and therapy of colon cancer by targeting microbiota. We discuss the challenges lie ahead and the future direction in studying gut microbiome in colon cancer to close the gap between the basic sciences and clinical application.

Fatal Clostridium septicum infection in a patient with a hematological malignancy

A 49-year-old woman with acute myeloid transformation of myelodysplastic syndrome was admitted with mild erythema and pain in the right thigh and left forearm. She was doing well and had been discharged the previous day after consolidation chemotherapy. Examination showed only mild erythema and tenderness of the right thigh. She was started on broad-spectrum antibiotics. Discoloration progressed rapidly, and within hours the right femoral and left brachial pulses were not palpable. She was taken to the operating room for a suspicion of embolic arterial occlusion. Surgical incision, however, revealed extensive necrosis of the tissues with the presence of gas. Her relatives did not want her to undergo amputation. The patient developed refractory hypotension and died within 15 hours of presentation. Blood samples later tested positive for Clostridium septicum. This case is presented to create awareness about the subtle presentation and rapid progression of this infection, which can lead to death in less than 24 hours.

Streptococcus bovis endocarditis and colon cancer: myth or reality? A case report and literature review

A relationship between infective endocarditis and colon cancer was established in 1950, and Streptococcus bovis was successfully isolated in 1970. However, this association and its pathogenesis still remain unclear. In this paper, we describe the clinical case of a patient with a history of colon cancer and infective endocarditis caused by Streptococcus bovis. The role of S bovis as an aetiological agent in the development of colon cancer is intriguing but uncertain. S bovis infection should be considered a silent sign of gastrointestinal malignancy or hepatic disease. We believe that in order to demonstrate the presence of colon cancer, all patients with S bovis infection require an endoscopic investigation of the colon.

A bacterial driver-passenger model for colorectal cancer: beyond the usual suspects

Cancer has long been considered a genetic disease. However, accumulating evidence supports the involvement of infectious agents in the development of cancer, especially in those organs that are continuously exposed to microorganisms, such as the large intestine. Recent next-generation sequencing studies of the intestinal microbiota now offer an unprecedented view of the aetiology of sporadic colorectal cancer and have revealed that the microbiota associated with colorectal cancer contains bacterial species that differ in their temporal associations with developing tumours. Here, we propose a bacterial driver-passenger model for microbial involvement in the development of colorectal cancer and suggest that this model be incorporated into the genetic paradigm of cancer progression.

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.

The association of Streptococcus bovis/gallolyticus with colorectal tumors: the nature and the underlying mechanisms of its etiological role

Streptococcus bovis (S. bovis) bacteria are associated with colorectal cancer and adenoma. S. bovis is currently named S. gallolyticus. 25 to 80% of patients with S. bovis/gallolyticus bacteremia have concomitant colorectal tumors. Colonic neoplasia may arise years after the presentation of bacteremia or infectious endocarditis of S. bovis/gallolyticus. The presence of S. bovis/gallolyticus bacteremia and/or endocarditis is also related to the presence of villous or tubular-villous adenomas in the large intestine. In addition, serological relationship of S. gallolyticus with colorectal tumors and direct colonization of S. gallolyticus in tissues of colorectal tumors were found. However, this association is still under controversy and has long been underestimated. Moreover, the etiological versus non-etiological nature of this associationis not settled yet. Therefore, by covering the most of up to date studies, this review attempts to clarify the nature and the core of S. bovis/gallolyicus association with colorectal tumors and analyze the possible underlying mechanisms.

Infectious causes of colorectal cancer

Colorectal cancer is a major cause of cancer-related morbidity and mortality in the United States and many other regions of the world. Our understanding of the pathogenesis of colorectal cancer, from the precursor adenomatous polyp to adenocarcinoma, has evolved rapidly. Colorectal carcinogenesis is a sequential process characterized by the accumulation of multiple genetic and molecular alterations in colonic epithelial cells. However, the development of colorectal cancer involves more then just a genetic predisposition. External or environmental factors presumably play a significant role, and inflammatory bowel diseases, obesity, alcohol consumption, and a diet high in fat and low in fiber have all been implicated as risk factors for the development of either colonic adenomas or carcinomas. We are becoming increasingly aware of microbes as causes of malignancies. This article reviews the various microbes that have been associated with the development of colorectal carcinomas.

Molecular detection, quantification, and isolation of Streptococcus gallolyticus bacteria colonizing colorectal tumors: inflammation-driven potential of carcinogenesis via IL-1, COX-2, and IL-8

Background

Colorectal cancer (CRC) has long been associated with bacteremia and/or endocarditis by Streptococcus gallolyticus member bacteria (SGMB) but the direct colonization of SGMB along with its molecular carcinogenic role, if any, has not been investigated. We assessed the colonization of SGMB in CRC patients with history of bacteremia (CRC-w/bac) and without history of bacteremia (CRC-wo/bac) by isolating SGMB from feces, mucosal surfaces of colorectum, and colorectal tissues and detecting SGMB DNA, via PCR and in situ hybridization (ISH) assays targeting SodA gene in colorectal tissues. Moreover, mRNA of IL1, IL-8, COX-2, IFN-γ, c-Myc, and Bcl-2 in colorectal tissues of studied groups was assessed via ISH and RT-PCR.

Results

SGMB were found to be remarkably isolated in tumorous (TU) and non-tumorous (NTU) tissues of CRC-w/bac, 20.5% and 17.3%, and CRC-wo/bac, 12.8% and 11.5%, respectively while only 2% of control tissues revealed SGMB (P < 0.05); such contrast was not found in mucosal and fecal isolation of SGMB. The positive detection of SGMB DNA in TU and NTU of CRC-w/bac and CRC-wo/bac via PCR, 48.7%, 35.9%, 32.7%, and 23%, respectively, and ISH, 46.1%, 30.7%, 28.8%, and 17.3%, respectively, was higher than in control tissues, 4 and 2%, respectively (P < 0.05). SGMB count measured via quantitative PCR of SGMB DNA in terms of copy number (CN), in TU and NTU of CRC-w/bac and CRC-wo/bac, 2.96-4.72, 1.29-2.81, 2.16-2.92, and 0.67-2.07 log₁₀ CN/g respectively, showed higher colonization in TU than in NTU and in CRC-w/bac than in CRC-wo/bac (P < 0.05). The PCR-based mRNA ratio and ISH-based percentage of positively stained cells of IL-1, 1.77 and 70.3%, COX-2, 1.63 and 44.8%, and IL-8, 1.73 and 70.3%, respectively, rather than IFN-γ, c-Myc, and Bcl-2, were higher in SGMB positive patients than in control or SGMB negative patients (P < 0.05).

Conclusions

The current study indicated that colorectal cancer is remarkably associated with SGMB; moreover, molecular detection of SGMB in CRC was superior to link SGMB with CRC tumors highlighting a possible direct and active role of SGMB in CRC development through most probably inflammation-based sequel of tumor development or propagation via, but not limited to, IL-1, COX-2, and IL-8.

Gas gangrene of the thigh in a morbidly obese patient with occult colon cancer

SUMMARY

We report a case of atraumatic gas gangrene and myonecrosis of the leg secondary to infection with Clostridium septicum in a severely obese patient with an occult cancer. She was treated successfully for both conditions. A review of the current literature describes this constellation of findings and the appropriate treatment.:

Genome sequence of Streptococcus gallolyticus: insights into its adaptation to the bovine rumen and its ability to cause endocarditis

Streptococcus gallolyticus (formerly known as Streptococcus bovis biotype I) is an increasing cause of endocarditis among streptococci and frequently associated with colon cancer. S. gallolyticus is part of the rumen flora but also a cause of disease in ruminants as well as in birds. Here we report the complete nucleotide sequence of strain UCN34, responsible for endocarditis in a patient also suffering from colon cancer. Analysis of the 2,239 proteins encoded by its 2,350-kb-long genome revealed unique features among streptococci, probably related to its adaptation to the rumen environment and its capacity to cause endocarditis. S. gallolyticus has the capacity to use a broad range of carbohydrates of plant origin, in particular to degrade polysaccharides derived from the plant cell wall. Its genome encodes a large repertoire of transporters and catalytic activities, like tannase, phenolic compounds decarboxylase, and bile salt hydrolase, that should contribute to the detoxification of the gut environment. Furthermore, S. gallolyticus synthesizes all 20 amino acids and more vitamins than any other sequenced Streptococcus species. Many of the genes encoding these specific functions were likely acquired by lateral gene transfer from other bacterial species present in the rumen. The surface properties of strain UCN34 may also contribute to its virulence. A polysaccharide capsule might be implicated in resistance to innate immunity defenses, and glucan mucopolysaccharides, three types of pili, and collagen binding proteins may play a role in adhesion to tissues in the course of endocarditis.

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.

Ecology and pathogenicity of gastrointestinal Streptococcus bovis

Streptococcus bovis is an indigenous resident in the gastrointestinal tracts of both humans and animals. S. bovis is one of the major causes of bacterial endocarditis and has been implicated in the incidence of human colon cancer, possibly due to chronic inflammatory response at the site of intestinal colonization. Certain feeding regimens in ruminants can lead to overgrowth of S. bovis in the rumen, resulting in the over-production of lactate and capsular polysaccharide causing acute ruminal acidosis and bloat, respectively. There are multiple strategies in controlling acute lactic acidosis and bloat. The incidence of the two diseases may be controlled by strict dietary management. Gradual introduction of grain-based diets and the feeding of coarsely chopped roughage decrease the incidence of the two disease entities. Ionophores, which have been used to enhance feed conversion and growth rate in cattle, have been shown to inhibit the growth of lactic acid bacteria in the rumen. Other methods of controlling lactic acid bacteria in the ruminal environment (dietary supplementation of long-chain fatty acids, induction of passive and active immune responses to the bacteria, and the use of lytic bacteriophages) have also been investigated. It is anticipated that through continued in-depth ecological analysis of S. bovis the characteristics responsible for human and animal pathogenesis would be sufficiently identified to a point where more effective control strategies for the control of this bacteria can be developed.

Colonoscopy is mandatory after Streptococcus bovis endocarditis: a lesson still not learned. Case report

Background

Even though the relationship between certain bacterial infections and neoplastic lesions of the colon is well-recognized, this knowledge has not been sufficiently translated into routine practice yet.

Case presentation

We describe the case of a 51-year-old man who was admitted to our Surgical Department due to rectal bleeding and abdominal pain. Preoperative colonoscopy, staging exams and subsequent surgery demonstrated a stenotic adenocarcinoma of the sigmoid colon, invading the left urinary tract and the homolateral bladder wall, with regional lymph nodes involvement and massive bilobar liver metastases (T4N1M1). After Hartmann's rectosigmoidectomy and despite systemic chemotherapy, a rapid progression occurred and the patient survived for only 5 months after diagnosis. Five years before detecting this advanced colonic cancer, the patient underwent aortic valve replacement due to a severe Streptococcus bovis endocarditis. Subsequent to this infection he never underwent a colonoscopy until overt intestinal symptoms appeared.

Conclusion

As this case illustrates, in the unusual setting of a Streptococcus bovis infection, it is necessary to timely and carefully rule out occult colon cancer and other malignancies during hospitalization and, if a tumor is not found, to schedule endoscopic follow-up. Rigorous application of these recommendations in the case described would have likely led to an earlier diagnosis of cancer and maybe saved the patient's life.

Phenotyping Clostridium septicum infection: a surgeon's infectious disease

BACKGROUND

Clostridium septicum infection is associated with malignancy. Whether disease phenotype is affected by malignant status is not known. Surgical treatment is used frequently but its impact on survival has not been examined in a cohort >30 patients.

METHODS

A PubMed search of English language journal articles yielded 320 cases. Full information (infection location, cancer type, operative intervention, and survival) was available for 224 cases + 7 at our institution not previously reported.

RESULTS

Seventy-two percent of patients had malignancy or malady of the gastrointestinal (GI) or hematologic (HEME) organ systems. HEME survival was inferior to GI survival (35% versus 55%, P = 0.03). Overall, patients who underwent operation had improved survival (57% versus 26%; P < 0.0001) and this association was maintained within GI and HEME cohorts (P = 0.002 and 0.005, respectively). More GI than HEME patients underwent operation (81% versus 51%, P < 0.001). GI patients were more likely than HEME patients to experience infection of skin and soft tissues (SSTI, P = 0.006). Diabetics were more likely to experience SSTI than nondiabetics (77% versus 45%, P < 0.001).

CONCLUSIONS

C. septicum infectious phenotype varies with host milieu. The SSTI phenotype is more common in GI and diabetic patients. This recognition may aid in directing the search for occult malignancy, which must be performed given the >70% incidence of concomitant cancer. This infection is more fatal in HEME versus GI patients, perhaps due in part to less HEME group operative intervention. Primary surgical therapy should be considered in GI or HEME patients as operative intervention benefits both groups.