Colorectal Cancer Associated with Streptococcus anginosus Bacteremia and Liver Abscesses

Streptococcus anginosus: A new pathogen of superficial gastritis, atrophic gastritis and gastric cancer

A wealth of research indicates that superficial gastritis (SG) and atrophic gastritis (AG) are precursors to gastric cancer (GC). While Helicobacter pylori (H. pylori) has long been recognized as a key player in GC development, recent findings by Fu et al. have identified Streptococcus anginosus (S. anginosus) as an emerging pathogen that can trigger SG, AG and GC. S. anginosus, a gram-positive coccus, leverages its surface protein T. pallidum membrane protein C (TMPC) to engage with the annexin A2 (ANXA2) receptor of gastric epithelial cells, facilitating its colonization and invasion in the gastric mucosa. This leads to an upregulation of proinflammatory chemokines Ccl20 and Ccl8, causing prolonged effects on gastric barrier function and microbiota homeostasis, leading to SG. Moreover, these bacteria activate the mitogen-activated protein kinase (MAPK) signaling pathway, which is associated with the development of AG and GC. Importantly, inhibiting TMPC or knocking down ANXA2 can reduce S. anginosus colonization and invasion, lowering the chances of SG, AG, and GC. This paper highlights the molecular mechanisms of S. anginosus in SG, AG and GC, emphasizing the importance of a multi-pathogen strategy in gastric disease management and the need for further investigation into the role of S. anginosus in GC progression.

Metagenomic Analysis of Biliary Microbial Flora in Patients with Gallbladder Cancer or Gallstones-Associated Chronic Cholecystitis

Biliary dysbiosis is associated with gallbladder cancer (GBC). We aimed to look for biliary bacteria specifically detected in GBC patients. We used 16S rRNA-based metagenomic analysis to elucidate biliary microbiota in 30 GBC and 30 gallstones-associated chronic cholecystitis patients. Relative abundance of five genera, Streptococcus, Enterococcus, Halomonas, Escherichia and Caulobacter was significantly associated with GBC. Of 15-species, 7 were detected significantly higher in GBC, Streptococcus anginosus, Streptococcus constellatus, Streptococcus intermedius, Actinomyces bowdenii, Actinomyces israelii, Actinomyces gerencseriae, and Escherichia fergusonii were biosafety level-2 infectious bacteria; other 8 species were biosafety level-1 bacteria. These bacterial species may be involved in pathogenesis of GBC.

Insights into the enigma of oral streptococci in carcinogenesis

SUMMARYThe genus Streptococcus consists of a taxonomically diverse group of Gram-positive bacteria that have earned significant scientific interest due to their physiological and pathogenic characteristics. Within the genus Streptococcus, viridans group streptococci (VGS) play a significant role in the oral ecosystem, constituting approximately 80% of the oral biofilm. Their primary role as pioneering colonizers in the oral cavity with multifaceted interactions like adherence, metabolic signaling, and quorum sensing contributes significantly to the complex dynamics of the oral biofilm, thus shaping oral health and disease outcomes. Perturbations in oral streptococci composition drive oral dysbiosis and therefore impact host-pathogen interactions, resulting in oral inflammation and representing VGS as an opportunistic pathogen. The association of oral streptococci in tumors across distant organs, spanning the esophagus, stomach, pancreas, and colon, illuminates a potential association between oral streptococci, inflammation, and tumorigenesis. This finding emphasizes the need for further investigations into the role of oral streptococci in mucosal homeostasis and their involvement in carcinogenesis. Hence, here, we review the significance of oral streptococci in biofilm dynamics and how the perturbation may impact mucosal immunopathogenesis in the context of cancer, with a vision of exploiting oral streptococci for cancer intervention and for the development of non-invasive cancer diagnosis.

Oral streptococci S. anginosus and S. mitis induce distinct morphological, inflammatory, and metabolic signatures in macrophages

Oral streptococci, key players in oral biofilm formation, are implicated in oral dysbiosis and various clinical conditions, including dental caries, gingivitis, periodontal disease, and oral cancer. Specifically, Streptococcus anginosus is associated with esophageal, gastric, and pharyngeal cancers, while Streptococcus mitis is linked to oral cancer. However, no study has investigated the mechanistic links between these Streptococcus species and cancer-related inflammatory responses. As an initial step, we probed the innate immune response triggered by S. anginosus and S. mitis in RAW264.7 macrophages. These bacteria exerted time- and dose-dependent effects on macrophage morphology without affecting cell viability. Compared with untreated macrophages, macrophages infected with S. anginosus exhibited a robust proinflammatory response characterized by significantly increased levels of inflammatory cytokines and mediators, including TNF, IL-6, IL-1β, NOS2, and COX2, accompanied by enhanced NF-κB activation. In contrast, S. mitis-infected macrophages failed to elicit a robust inflammatory response. Seahorse Xfe96 analysis revealed an increased extracellular acidification rate in macrophages infected with S. anginosus compared with S. mitis. At the 24-h time point, the presence of S. anginosus led to reduced extracellular itaconate, while S. mitis triggered increased itaconate levels, highlighting distinct metabolic profiles in macrophages during infection in contrast to aconitate decarboxylase expression observed at the 6-h time point. This initial investigation highlights how S. anginosus and S. mitis, two Gram-positive bacteria from the same genus, can prompt distinct immune responses and metabolic shifts in macrophages during infection.IMPORTANCEThe surge in head and neck cancer cases among individuals devoid of typical risk factors such as Human Papilloma Virus (HPV) infection and tobacco and alcohol use sparks an argumentative discussion around the emerging role of oral microbiota as a novel risk factor in oral squamous cell carcinoma (OSCC). While substantial research has dissected the gut microbiome's influence on physiology, the oral microbiome, notably oral streptococci, has been underappreciated during mucosal immunopathogenesis. Streptococcus anginosus, a viridans streptococci group, has been linked to abscess formation and an elevated presence in esophageal cancer and OSCC. The current study aims to probe the innate immune response to S. anginosus compared with the early colonizer Streptococcus mitis as an important first step toward understanding the impact of distinct oral Streptococcus species on the host immune response, which is an understudied determinant of OSCC development and progression.

The Clinical View on Streptococcus anginosus Group – Opportunistic Pathogens Coming Out of Hiding

Three distinct streptococcal species: Streptococcus anginosus, Streptococcus intermedius, and Streptococcus constellatus, belonging to the Streptococcus anginosus group (SAG), also known as Streptococcus milleri group, have been attracting clinicians and microbiologists, not only as oral commensals but also as opportunistic pathogens. For years they have been simply classified as so called viridans streptococci, and distinct species were not associated with particular clinical manifestations. Therefore, description of SAG members are clearly underrepresented in the literature, compared to other medically relevant streptococci. However, the increasing number of reports of life-threatening infections caused by SAG indicates their emerging pathogenicity. The improved clinical data generated with the application of modern molecular diagnostic techniques allow for precise identification of individual species belonging to SAG. This review summarizes clinical reports on SAG infections and systematizes data on the occurrence of individual species at the site of infection. We also discuss the issue of proper microbiological diagnostics, which is crucial for further clinical treatment.

Isolation of pancreatic microbiota from cystic precursors of pancreatic cancer with intracellular growth and DNA damaging properties

Emerging research suggests gut microbiome may play a role in pancreatic cancer initiation and progression, but cultivation of the cancer microbiome remains challenging. This pilot study aims to investigate the possibility to cultivate pancreatic microbiome from pancreatic cystic lesions associated with invasive cancer. Intra-operatively acquired pancreatic cyst fluid samples showed culture-positivity mainly in the intraductal papillary mucinous neoplasm (IPMN) group of lesions. MALDI-TOF MS profiling analysis shows Gammaproteobacteria and Bacilli dominate among individual bacteria isolates. Among cultivated bacteria, Gammaproteobacteria, particularly Klebsiella pneumoniae, but also Granulicatella adiacens and Enterococcus faecalis, demonstrate consistent pathogenic properties in pancreatic cell lines tested in ex vivo co-culture models. Pathogenic properties include intracellular survival capability, cell death induction, or causing DNA double-strand breaks in the surviving cells resembling genotoxic effects. This study provides new insights into the role of the pancreatic microbiota in the intriguing link between pancreatic cystic lesions and cancer.

Metagenomic analysis of primary colorectal carcinomas and their metastases identifies potential microbial risk factors

The paucity of microbiome studies at intestinal tissues has contributed to a yet limited understanding of potential viral and bacterial cofactors of colorectal cancer (CRC) carcinogenesis or progression. We analysed whole-genome sequences of CRC primary tumours, their corresponding metastases and matched normal tissue for sequences of viral, phage and bacterial species. Bacteriome analysis showed Fusobacterium nucleatum, Streptococcus sanguinis, F. Hwasookii, Anaerococcus mediterraneensis and further species enriched in primary CRCs. The primary CRC of one patient was enriched for F. alocis, S. anginosus, Parvimonas micra and Gemella sp. 948. Enrichment of Escherichia coli strains IAI1, SE11, K-12 and M8 was observed in metastases together with coliphages enterobacteria phage φ80 and Escherichia phage VT2φ_272. Virome analysis showed that phages were the most preponderant viral species (46%), the main families being Myoviridae, Siphoviridae and Podoviridae. Primary CRCs were enriched for bacteriophages, showing five phages (Enterobacteria, Bacillus, Proteus, Streptococcus phages) together with their pathogenic hosts in contrast to normal tissues. The most frequently detected, and Blast-confirmed, viruses included human endogenous retrovirus K113, human herpesviruses 7 and 6B, Megavirus chilensis, cytomegalovirus (CMV) and Epstein-Barr virus (EBV), with one patient showing EBV enrichment in primary tumour and metastases. EBV was PCR-validated in 80 pairs of CRC primary tumour and their corresponding normal tissues; in 21 of these pairs (26.3%), it was detectable in primary tumours only. The number of viral species was increased and bacterial species decreased in CRCs compared with normal tissues, and we could discriminate primary CRCs from metastases and normal tissues by applying the Hutcheson t-test on the Shannon indices based on viral and bacterial species. Taken together, our results descriptively support hypotheses on microorganisms as potential (co)risk factors of CRC and extend putative suggestions on critical microbiome species in CRC metastasis.

A Case of Necrotizing Soft Tissue Infection Secondary to Perforated Colon Cancer

Necrotizing soft tissue infections are aggressive infections that cause necrosis of muscle, fascia, and tissue. They typically follow fascial planes that lack insufficient blood supply. Early drainage and debridement are essential for survival in these patients. This is a case of a patient who presented in diabetic ketoacidosis with a necrotizing soft tissue infection localized to the left flank and abdomen with underlying colon cancer pathology.

The patient was a 54-year-old female who initially presented with acute dyspnea and left flank pain for two weeks. On admission, she was afebrile, tachycardic, tachypneic, and hypertensive. After being transferred to the ICU for diabetic ketoacidosis management, she began complaining of left abdominal pain and the CT showed concerns for a possible necrotizing soft tissue infection in the left flank region. She was taken to the operating room immediately for debridement and started on broad-spectrum antibiotics. The next day, an exploratory laparotomy was performed with a hemicolectomy and creation of an end colostomy due to concern for a perforated colonic malignancy. A final debridement was completed and a wound vacuum-assisted closure (VAC) was placed. Final pathology demonstrated well-differentiated colonic adenocarcinoma invading into the muscularis propria.

Overall, necrotizing soft tissue infections can be related to a perforated viscus especially a colonic malignancy and this case demonstrates the importance of proper surgical management and high clinical suspicion for possible underlying pathology in a soft tissue infection.

Colorectal Cancer Patients Have Four Specific Bacterial Species in Oral and Gut Microbiota in Common-A Metagenomic Comparison with Healthy Subjects

Simple Summary

The incidence of colorectal cancer (CRC) has been increasing in recent years, and the gut microbiota is nowadays considered to be involved in the progression of CRC. Recent studies have investigated the involvement of the oral microbiota in CRC development using saliva and stool samples. However, the details regarding how oral bacteria alter the gut microbiota and affect CRC carcinogenesis remain unclear. In the present study, we identified four bacterial species that may affect the carcinogenesis and progression of CRC. These microorganisms may be potential biomarkers in saliva for diagnosing CRC.

Abstract

Oral microbiota is reportedly associated with gut microbiota and influences colorectal cancer (CRC) progression; however, the details remain unclear. This study aimed to evaluate the role of oral microbiota in CRC progression. Fifty-two patients with CRC and 51 healthy controls were included. Saliva and stool samples were collected, and microbiota were evaluated using 16S rRNA analysis and next-generation sequencing. Comparative analysis was performed on both groups. Linear discriminant analysis effect size (LEfSe) revealed the presence of indigenous oral bacteria, such as Peptostreptococcus, Streptococcus, and Solobacterium spp., at a significantly higher relative abundance in saliva and stool samples of CRC patients compared with controls. Next, CRC patients were divided into early stage (Stage I, II; n = 26; 50%) and advanced stage (Stage III, IV; n = 26; 50%) disease. LEfSe revealed that S. moorei was present at a significantly higher relative abundance in the advanced-stage group compared with the early-stage group, again consistent for both saliva and stool samples. Among bacterial species with significantly higher relative abundance in CRC patients, P. stomatis, S. anginosus, S. koreensis, and S. moorei originated from the oral cavity, suggesting indigenous oral bacteria may have promoted initiation of CRC carcinogenesis. Furthermore, S. moorei may influence CRC progression.

Gut microbiota and fatigue in rectal cancer patients: a cross-sectional pilot study

CONTEXT

Although microbial-mediated disturbance of intestinal mucosal homeostasis (dysbiosis) is believed to contribute to the pathogenesis of chemotherapy and radiotherapy (CRT)-related fatigue, potential differences in the gut microbial diversity and in the abundance of gut microbial taxa between fatigued and non-fatigued patients have not been adequately examined, particularly in the rectal cancer population.

PURPOSE

In this cross-sectional study, we aim to examine the differences in (a) gut microbial diversity and gut microbial abundances and (b) predicted functional pathways of the gut microbiome between rectal cancer participants with and without fatigue at the end of CRT.

METHODS

Rectal cancer patients (n = 50) provided stool samples for 16S rRNA gene sequencing and symptom ratings for fatigue at the end of CRT. Gut microbiome data were analyzed using QIIME2, LEfSe, and the R statistical package.

RESULTS

Fatigued (n = 35) participants showed enriched bacterial abundances of Eubacterium, Streptococcus, Adlercreutzia, and Actinomyces, as well as enriched abundances of the microbial sucrose degradation pathway, compared to non-fatigued patients at the end of CRT (n = 15).

CONCLUSIONS

Differentially abundant microbial taxa were identified in fatigued and non-fatigued rectal cancer participants at the end of CRT. However, the exact role of these taxa (and identification of species) in the biology of CRT-related fatigue remains to be examined.

Vaginal Microbiome-Based Bacterial Signatures for Predicting the Severity of Cervical Intraepithelial Neoplasia

Although emerging evidence revealed that the gut microbiome served as a tool and as biomarkers for predicting and detecting specific cancer or illness, it is yet unknown if vaginal microbiome-derived bacterial markers can be used as a predictive model to predict the severity of CIN. In this study, we sequenced V3 region of 16S rRNA gene on vaginal swab samples from 66 participants (24 CIN 1−, 42 CIN 2+ patients) and investigated the taxonomic composition. The vaginal microbial diversity was not significantly different between the CIN 1− and CIN 2+ groups. However, we observed Lactobacillus amylovorus dominant type (16.7%), which does not belong to conventional community state type (CST). Moreover, a minimal set of 33 bacterial species was identified to maximally differentiate CIN 2+ from CIN 1− in a random forest model, which can distinguish CIN 2+ from CIN 1− (area under the curve (AUC) = 0.952). Among the 33 bacterial species, Lactobacillus iners was selected as the most impactful predictor in our model. This finding suggests that the random forest model is able to predict the severity of CIN and vaginal microbiome may play a role as biomarker.

Splenic abscess caused by Streptococcus anginosus bacteremia secondary to urinary tract infection: a case report and literature review

Organ abscesses caused by Streptococcus anginosus are relatively rare. We report the case of an elderly woman with splenic abscess caused by S. anginosus bacteremia after urinary tract infection. An 82-year-old woman had a history of frequency of urination, urgency, and fever with chills for over 10 days prior to admission. An abdominal computed tomography (CT) scan performed in the emergency room revealed a low-density lesion in the spleen, kidney cysts, some exudation around the kidney, and cystitis should be valued. She was treated with ceftriaxone and imipenem/cilastatin. After admission, the blood culture yielded positive results for S. anginosus. A contrast-enhanced abdominal CT scan showed that the low-density lesion previously found in the spleen was smaller than before. After percutaneous drainage of the splenic abscess and treatment with piperacillin/tazobactam based on the antibiotic sensitivity pattern, repeated abdominal CT scan revealed a significant reduction in the low-density lesion. The patient was discharged without recurrence or complications. A systematic review of organ abscess caused by S. anginosus bacteremia was performed. To our knowledge, there has been no report of splenic abscess caused by S. anginosus bacteremia secondary to urinary system tract infection, although urinary tract infections are also an important source.

A rare case of massive pericardial effusion due to spontaneous rupture of Streptococcus anginosus group liver abscess

Purulent pericardial effusion is a rare and life-threatening complication of pyogenic liver abscess if not diagnosed and intervened early. Due to its nonspecific presentation, diagnosis of pyogenic liver abscess is challenging. Herein, we discuss the case of a 31-year-old healthy male that presented with acute chest tightness for one day in the setting of spontaneous rupture of pyogenic liver abscess and developed transdiaphragmatic extension of purulent pericardial effusion. The abscess resolved with antibiotic therapy (beta-lactam), ultrasound-guided aspiration, and pericardial window. Culture of pericardial fluid yielded the Streptococcus anginosus group. He was subsequently discharged following clinical resolution and normalization of liver function tests after 15 days of treatment. Follow-up ultrasonography revealed that the liver abscess and pericardial effusion were resolved in 8 weeks post treatment and intervention.

An Extremely Rare Case of Streptococcus anginosus Bacteremia Associated With Colon Cancer and Infective Endocarditis

Streptococcus anginosus (S. anginosus) is a subgroup of viridans streptococci that tend to form a deep-seated abscess. These bacteria can be part of healthy human flora and commonly found in the gastrointestinal tract and oral cavity. Infective endocarditis is most commonly caused by Staphylococcus aureus and Streptococcus. Among the Streptococcus group, anginosus is extremely rare to cause endocarditis, and there are only a few case reports available. We present a patient with S. anginosus bacteremia who subsequently got diagnosed with metastatic colon cancer along with aortic and mitral valve endocarditis

Small Bowel Gastrointestinal Stromal Tumor as a Gateway for Streptococcus anginosus Causing Multiple Liver Abscesses

Gastrointestinal stromal tumors (GISTs) are the most common type of mesenchymal neoplasm of the gastrointestinal tract but consist of only 1% of all primary gastrointestinal neoplasms. Differentiated from other spindle cell tumors, GISTs are uniquely positive for CD117 expression which allows for molecular targeting therapy with imatinib mesylate (Gleevec). Clinical presentations are variable, ranging from asymptomatic to vague symptoms of abdominal pain, early satiety, abdominal distention or gastrointestinal bleeding. Very rarely, patients can present with tumor-bowel fistula and intra-abdominal abscesses. In this article, we discuss a rare presentation of a middle-aged male with multiple liver abscesses found to have a primary small bowel GIST. This patient received prompt intravenous antibiotics; however, hepatic abscesses can be easily misinterpreted as cystic hepatic metastases which can delay appropriate therapy. Streptococcus anginosus was found to be responsible for the formation of the liver abscesses visualized on computed tomography (CT) scan. Similar to Streptococcus bovis, knowledge in the literature is arising about the association between S. anginosus and gastrointestinal malignancies. This case highlights the importance of identifying concomitant primary GISTs with intra-hepatic abscesses, as these lesions can be easily misconstrued as liver metastases and consequently mismanaged. We herein emphasize that hepatic abscesses are a potential sequela of GISTs and should thus prompt further investigation for potential malignancies, if warranted, so that there is no delay in treatment of these gastrointestinal tumors.

Dysbiosis of the Gut Microbiome is associated with Tumor Biomarkers in Lung Cancer

Lung cancer is a malignancy with high morbidity and mortality worldwide. More evidences indicated that gut microbiome plays an important role in the carcinogenesis and progression of cancers by metabolism, inflammation and immune response. However, the study about the characterizations of gut microbiome in lung cancer is limited. In this study, the fecal samples were collected from 16 healthy individuals and 30 lung cancer patients who were divided into 3 groups based on different tumor biomarkers (cytokeratin 19 fragment, neuron specific enolase and carcinoembryonic antigen, respectively) and were analyzed using 16S rRNA gene amplicon sequencing. Each lung cancer group has characterized gut microbial community and presents an elimination, low-density, and loss of bacterial diversity microbial ecosystem compared to that of the healthy control. The microbiome structures in family and genera levels are more complex and significantly varied from each group presenting more different and special pathogen microbiome such as Enterobacteriaceae, Streptococcus, Prevotella, etc and fewer probiotic genera including Blautia, Coprococcus, Bifidobacterium and Lachnospiraceae. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and COG annotation demonstrated decreased abundance of some dominant metabolism-related pathways in the lung cancer. This study explores for the first time the features of gut microbiome in lung cancer patients and may provide new insight into the pathogenesis of lung cancer system, with the implication that gut microbiota may serve as a microbial marker and contribute to the derived metabolites, development and differentiation in lung cancer system.

Implications of the Genitourinary Microbiota in Prostatic Disease

PURPOSE OF REVIEW

To summarize recent investigation into associations between the genitourinary microbiota and prostatic disease.

RECENT FINDINGS

The genitourinary tract is not sterile. There are microbial communities (microbiota) in each niche of the genitourinary tract including the bladder, prostate, and urethra, which have been the subject of increasing scientific interest. Investigators have utilized several unique methods to study them, resulting in a highly heterogeneous body of literature. To characterize these genitourinary microbiota, diverse clinical specimens have been analyzed, including urine obtained by various techniques, seminal fluid, expressed prostatic secretions, and prostatic tissue. Recent studies have attempted to associate the microbiota detected from these samples with urologic disease and have implicated the genitourinary microbiota in many common conditions, including benign prostatic hyperplasia (BPH), prostate cancer, and chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). In this review, we summarize the recent literature pertaining to the genitourinary microbiota and its relationship to the pathophysiology and management of three common prostatic conditions: BPH, prostate cancer, and CP/CPPS.

The microbiome in prostate inflammation and prostate cancer

BACKGROUND

The human microbiome may influence prostate cancer initiation and/or progression through both direct and indirect interactions. To date, the majority of studies have focused on direct interactions including the influence of prostate infections on prostate cancer risk and, more recently, on the composition of the urinary microbiome in relation to prostate cancer. Less well understood are indirect interactions of the microbiome with prostate cancer, such as the influence of the gastrointestinal or oral microbiota on pro- or anti-carcinogenic xenobiotic metabolism, and treatment response.

METHODS

We review the literature to date on direct and indirect interactions of the microbiome with prostate inflammation and prostate cancer.

RESULTS

Emerging studies indicate that the microbiome can influence prostate inflammation in relation to benign prostate conditions such as prostatitis/chronic pelvic pain syndrome and benign prostatic hyperplasia, as well as in prostate cancer. We provide evidence that the human microbiome present at multiple anatomic sites (urinary tract, gastrointestinal tract, oral cavity, etc.) may play an important role in prostate health and disease.

CONCLUSIONS

In health, the microbiome encourages homeostasis and helps educate the immune system. In dysbiosis, a systemic inflammatory state may be induced, predisposing remote anatomical sites to disease, including cancer. The microbiome's ability to affect systemic hormone levels may also be important, particularly in a disease such as prostate cancer that is dually affected by estrogen and androgen levels. Due to the complexity of the potential interconnectedness between prostate cancer and the microbiome, it is vital to further explore and understand the relationships that are involved.

Liver Abscess due to Streptococcus constellatus in an Immunocompetent Adult: A Less Known Entity

BACKGROUND

Pyogenic liver abscesses (PLAs) are an uncommon, but potentially life threatening infection. We report a case of PLA due to Streptococcus constellatus, a member of the Streptococcus anginosus group (SAG) bacteria, commonly found as commensals of the oropharyngeal, gastrointestinal and genitourinary flora.

CASE

The patient, a 42-year-old man with no premorbidities, non-smoker and non-alcoholic, presented to our hospital with high-grade fever associated with chills and rigors and right upper quadrant pain of one month duration. Culture of the ultrasound-guided liver aspirate yielded a pure growth of S. constellatus subspecies constellatus identified by conventional biochemical tests. In a standard antimicrobial disk-diffusion test, the isolate was susceptible to cefepime, cefotaxime, ceftriaxone, vancomcyin, levofloxacin, clindamycin and linezolid. Treatment with parenteral ceftriaxone alongwith appropriate surgical management led to resolution of the abscess with no recurrence of infection at three months follow-up.

CONCLUSIONS

The pathogenic potential of SAG has generally been disregarded because of the commensal nature of these microorganisms; however, streptococci belonging to this group have been increasingly reported as relevant pathogens in abscesses and blood cultures. An underlying condition, such as diabetes, cirrhosis or cancer or some medical manipulation, such as dental extraction, acupuncture, or hemorrhoidectomy is associated with the majority of patients with SAG abscess. However, the present case highlights the need to include S. constellatus and other members of the SAG while investigating for etiology of PLA, even in immunocompetent adults.

Colon Carcinoma Presenting as Streptococcus anginosus Bacteremia and Liver Abscess

A collection of dead white blood cells within the liver is called a liver abscess, and pyogenic liver abscess (PLA) is the most common type. PLA is commonly associated with biliary tract infections. However, in this case report, we present a rare cause of Streptococcus anginosus bacteremia and PLA which is associated with a carcinoma of the colon at the splenic flexure. The presentation mimicked a cholecystitis clinically, but the radio-imaging revealed a liver abscess. Blood cultures revealed an uncommon etiological agent, S. anginosus group which is otherwise a commensal in the human gut. In this case report, we aimed to summarize the microbiological aspects of S. anginosus group of organisms, the relevant clinicopathological considerations and the management.

Ileal GIST presenting with bacteremia and liver abscess: A case report and review of literature

INTRODUCTION

Small intestine gastrointestinal stromal tumors can infrequently present with intra-abdominal abscess, perforation, obstruction or fistula. Tumor-small intestine fistula is a rare phenomenon and occurs as a result of GISTs' propensity to cause mucosal ulceration. This allows bacteria from the gut to gain access to the systemic circulation and predisposes the patient to bacteremia and pyogenic liver abscess.

PRESENTATION OF CASE

We present a case of a 63-year-old female whose initial symptoms included fever, nausea, vomiting and right upper quadrant pain. Radiologic studies revealed a liver lesion and an intra-abdominal mass containing oral contrast, suggesting involvement of the gastrointestinal tract. She was found to have a liver abscess, Streptococcus anginosus bacteremia and an ileal GIST that formed a fistula between the tumor and small intestine. We performed a surgical resection of the tumor and percutaneous drainage of the liver abscess. Imatinib was initiated post operatively and she experienced no recurrence, as demonstrated by a surveillance computed tomography scan at 12 months.

CONCLUSION

Findings of a liver lesion in association with a small intestine GIST should raise concern for both metastatic disease and a possible infectious complication such as a pyogenic liver abscess. If a member of the Streptococcus milleri group is isolated in blood cultures, a consideration for gastrointestinal malignancy is imperative. This case report reviews a rare presentation of an ileal GIST with tumor-intestinal fistula, complicated by liver abscess and Streptococcus anginosus bacteremia.