The Association of Streptococcus gallolyticus Subspecies pasteurianus Bacteremia with the Detection of Premalignant and Malignant Colonic Lesions

Sciatica caused by spinal epidural abscess as the initial clinical presentation of colon cancer: a rare case report and review of literature

BACKGROUND

Colorectal cancer is one of the most frequently diagnosed forms of cancer, and it is associated with several common symptoms and signs such as rectal bleeding, altered bowel habits, abdominal pain, anemia, and unintentional weight loss. Sciatica, a debilitating condition in which the patient experiences paresthesia and pain in the dermatome of associated lumbosacral nerve roots or sciatic nerve distribution, is not considered one of these. Here we present a case of colorectal cancer manifesting symptoms of sciatica alone.

CASE PRESENTATION

A 68-year-old male presented with progressive lower back pain radiating to his left thigh and calf over L5/S1 dermatome. Sciatica was suspected and initially underwent conservative treatment with analgesics. However, the symptoms progressed and MRI revealed an epidural abscess surprisingly. Surgical debridement was performed and pus culture isolated Streptococcus gallolyticus. Based on the strong association of S. gallolyticus with colorectal cancer, the presence of this pathogen prompted further tumor evaluation, even in the absence of the typical symptoms and signs. This investigation ultimately leads to the diagnosis of sigmoid adenocarcinoma.

CONCLUSIONS

Although rare, sciatica caused by S. gallolyticus infection of the spinal epidural space may serve as the initial presentation of colorectal cancer. Physicians should be aware of the strong association between S. gallolyticus and colorectal cancer. Based on what we currently know about the condition; a thorough systematic assessment of occult neoplasia for patients with S. gallolyticus infection is recommended.

Global proteomic identifies multiple cancer-related signaling pathways altered by a gut pathobiont associated with colorectal cancer

In this work, we investigated the oncogenic role of Streptococcus gallolyticus subsp. gallolyticus (SGG), a gut bacterium associated with colorectal cancer (CRC). We showed that SGG UCN34 accelerates colon tumor development in a chemically induced CRC murine model. Full proteome and phosphoproteome analysis of murine colons chronically colonized by SGG UCN34 revealed that 164 proteins and 725 phosphorylation sites were differentially regulated. Ingenuity Pathway Analysis (IPA) indicates a pro-tumoral shift specifically induced by SGG UCN34, as ~ 90% of proteins and phosphoproteins identified were associated with digestive cancer. Comprehensive analysis of the altered phosphoproteins using ROMA software revealed up-regulation of several cancer hallmark pathways such as MAPK, mTOR and integrin/ILK/actin, affecting epithelial and stromal colonic cells. Importantly, an independent analysis of protein arrays of human colon tumors colonized with SGG showed up-regulation of PI3K/Akt/mTOR and MAPK pathways, providing clinical relevance to our findings. To test SGG's capacity to induce pre-cancerous transformation of the murine colonic epithelium, we grew ex vivo organoids which revealed unusual structures with compact morphology. Taken together, our results demonstrate the oncogenic role of SGG UCN34 in a murine model of CRC associated with activation of multiple cancer-related signaling pathways.

Infective Endocarditis as a Complication of Crohn's Disease on Immunotherapy

A patient with a history of Crohn's disease on infliximab presented to the hospital with sepsis and a new heart murmur. He was found to have native aortic valve infective endocarditis from a rare species of group D Streptococcusin his blood. The patient was also noted to be in an acute flare of Crohn's disease. The hospital course was complicated by florid heart failure from acute aortic insufficiency. He eventually improved after source control and appropriate antibiotic therapy. S. pasteuranis bacteremia and endocarditis are attributable to the patient's immunocompromised state as a result of infliximab treatment. While S. pasteuranis is infrequently grown in blood cultures, it is commonly found in normal gut flora. We hypothesize that it gained access to the bloodstream through the epithelium in the terminal ileum, which was inflamed due to an acute flare of Crohn's disease.

Pathogenic investigations of Streptococcus pasteurianus, an underreported zoonotic pathogen, isolated from a diseased piglet with meningitis

Streptococcus pasteurianus, an underreported opportunistic pathogen, is considered an increasingly recognized cause of meningitis and bacteremia in many animals and humans worldwide. However, except for some epidemiological studies, there is no report about the gene-deletion mutagenesis, virulence factors, reservoir niches or animal infection models for this pathogen. In this study, we first isolated an S. pasteurianus strain from a newly weaned piglet's brain with meningitis. The genomic sequence of this swine isolate WUSP067 shared high homology with that of two human strains. The comparative genome analysis showed that strain WUSP067 contained a fucose utilization cluster absent in human strains, and it shared 91% identity with that of an integrative and conjugative element (ICE) ICEssuZJ20091101-2 from Streptococcus suis, another important swine bacterial pathogen. Strain WUSP067 was resistant to erythromycin, tulathromycin, lincomycin, clindamycin, doxycycline and gentamycin, and ICEs are vehicles for harbouring antimicrobial resistance genes. The infection model was established using the 3-week-old newly weaned ICR mice. The 50% lethal dose value of strain WUSP067 was 4.0 × 107 colony-forming units per mouse. The infected mice showed severe signs of meningitis and pathological changes in brains. Furthermore, the capsule-deficient mutant was generated using natural transformation, and we showed that capsule was an essential virulence factor for S. pasteurianus. In addition, we found that tonsils and hilar lymph nodes of healthy pigs may be reservoir niches for this bacterium. Thus, our study provided valuable information about the pathogenetic characteristics and antimicrobial resistance of S. pasteurianus and paved the way for studying its pathogenesis.

Streptococcus gallolyticus subspecies pasteurianus bacteremia accompanied by acute pancreatitis

INTRODUCTION

While Streptococcus gallolyticus subsp. gallolyticus has a well-known association with colorectal cancer, an epidemiological association between S. gallolyticus subsp. pasteurianus (SGSP) and hepatobiliary diseases has been suggested. Here we described a case of gallstone pancreatitis and SGSP bacteremia in which species-identification by Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) helped to diagnose the biliary etiology.

CASE REPORT

A 61-year-old Japanese man without history of alcohol consumption was hospitalized for acute pancreatitis. His past medical history included endoscopically treated familial adenomatous polyposis. A blood culture grew gram-positive cocci, identified to be SGSP by MALDI-TOF MS. A contrast-enhanced computed tomography scan showed pancreatic enlargement and increased fatty tissue concentration around the perirenal and pararenal space. He was diagnosed with acute pancreatitis and subsequently recovered after appropriate antimicrobial therapy and supportive care. Subsequent magnetic resonance cholangiopancreatography showed gallstones in the gallbladder neck, suggesting the cause of the acute pancreatitis. Seven months after admission, cholecystectomy was performed for cholelithiasis.

CONCLUSION

This case highlights that the identification of subspecies enabled by MALDI-TOF MS supports the diagnosis of the underlying etiology from the microbiological point of view.

Eurasian beaver (Castor fiber) health surveillance in Britain: Assessing a disjunctive reintroduced population

BACKGROUND

Numerous translocations of Eurasian beavers have occurred with little implementation of standardised health screening. Pre-release health screening enables the selection of individuals with the best survival prospects and reduces potential health risks, but this is by-passed during unofficial releases. Beaver reintroduction to Britain has been haphazard and currently disjunctive populations of varying status exist.

METHODS

This observational cross section study investigated the health status of three beaver populations, with 90 live beavers tested for a range of pathogens comprising 56 from Tayside (unofficially released Scotland), nine from Knapdale (officially released Scotland) and 25 from Devon (unofficially released England). In addition, a further 32 cadavers were screened (25 from Tayside and seven from Knapdale).

RESULTS

All beavers were in good physical condition, did not harbour any non-native disease or parasites of concern and demonstrated remarkably low levels of any disease or parasite exposure.

CONCLUSION

Beavers are establishing and adapting well to British landscapes and are not acting as reservoirs of significant zoonotic diseases. Official, licensed reintroduction programmes may appear overly convoluted; however, reputational damage of unofficial releases should be considered, along with the health and welfare of the animals involved and collateral damage to other wildlife, domestic animals and humans.

Streptococcus bovis Contributes to the Development of Colorectal Cancer via Recruiting CD11b⁺TLR-4⁺ Cells

Background

An increasing number of studies have demonstrated that Streptococcus bovis and its concomitant inflammatory factors concentrate in the intestine in colorectal cancer (CRC). However, the molecular mechanism of S. bovis on colorectal tumorigenesis remains unclear. This study aimed to explore the role of S. bovis in carcinogenesis and its potential mechanism in CRC of mice orally pretreated with S. bovis.

Material/Methods

The colons of experimental mice were collected and evaluated for the extent of neoplasm. In addition, comparative feces DNA sequencing was adopted to verify the abundance change of S. bovis during the progression of CRC in patients.

Results

The results of this study found that S. bovis is more likely to be present at higher levels in patients with progressive colorectal carcinoma compared to those adenoma patients and healthy volunteers (P<0.05). Pretreatment with S. bovis aggravated tumor formation in mice, resulting in more substantial and a higher number of tumor nodes (P<0.05). A cytokine expression pattern with increased levels of IL-6, Scyb1, Ptgs2, IL-1β, TNF, and Ccl2 was detected in S. bovis pretreated CRC mice (all P<0.05). Furthermore, S. bovis recruited myeloid cells, especially CD11b⁺TLR-4⁺ cells, which could promote pro-tumor immunity in the tumor microenvironment (P<0.05).

Conclusions

Collectively, our study indicates that S. bovis may induce a suppressive immunity that is conducive to CRC by recruiting tumor-infiltrating CD11b⁺TLR-4⁺ cells. In conclusion, S. bovis contributes to colorectal tumorigenesis via recruiting CD11b⁺TLR-4⁺ cells.

Microbiological and clinical characteristics of Streptococcus gallolyticus subsp. pasteurianus infection in China

BACKGROUND

Infections by Streptococcus gallolyticus subsp. pasteurianus (SGSP) is often underestimated. Herein, the epidemiological features and resistant characteristics of SGSP in mainland China are characterized to enable a better understanding of its role in clinical infections.

METHODS

In the present work, 45 SGSP isolates were collected from the samples of bloodstream, urine, aseptic body fluid, and fetal membrane/placenta from patients in 8 tertiary general hospitals of 6 cities/provinces in China from 2011 to 2017. The identification of all isolates was performed using traditional biochemical methods, 16S rRNA and gyrB sequencing, followed by the characterization of their antibiotic resistance profiling and involved genes.

RESULTS

Among 34 non-pregnancy-related patients, 4 (4/34,11.8%) patients had gastrointestinal cancer, 10 (10/34, 29.4%) patients had diabetes, and one patient had infective endocarditis. Moreover, 11 cases of pregnant women were associated with intrauterine infection (9/11, 81.2%) and urinary tract infection (1/11, 9.1%), respectively. Except one, all other SGSP isolates were correctly identified by the BD Phoenix automated system. We found that all SGSP isolates were phenotypically susceptible to penicillin, ampicillin, cefotaxime, meropenem, and vancomycin. Forty strains (40/45, 88.9%) were both erythromycin and clindamycin-resistant, belonging to the cMLS_B phenotype, and the majority of them carried erm(B) gene (39/40, 97.5%). Although the cMLS_B/erm(B) constituted the most frequently identified phenotype/genotype combination (25/40, 62.5%) among all erythromycin-resistant cMLS_B isolates, erm(B)/erm(A), erm(B)/mef(A/E), and erm(B)/erm(T) was detected in 7, 4, and 3 isolates, respectively. Furthermore, 43 strains (43/45, 95.6%) were tetracycline-resistant, and out of these, 39 strains (39/45, 86.7%) carried tet(L), 27(27/45, 60.0%) strains carried tet(O), and 7 (7/45, 15.6%) strains carried tet(M), alone or combined, respectively. All erythromycin-resistant isolates were also resistant to tetracycline.

CONCLUSIONS

It is important to study and draw attention on SGSP, an underreported opportunistic pathogen targeting immunodeficient populations, notably elderly subjects, pregnant women and neonates.

Significance of Streptococcus gallolyticus subsp. gallolyticus Association With Colorectal Cancer

Streptococcus gallolyticus subsp. gallolyticus Sgg (formerly known as S. bovis type I) is the main causative agent of septicemia and infective endocarditis (IE) in elderly and immunocompromised persons. It belongs to the few opportunistic bacteria, which have been strongly associated to colorectal cancer (CRC). A literature survey covering a period of 40 years (1970–2010) revealed that 65% of patients diagnosed with an invasive Sgg infection had a concomitant colorectal neoplasia. Sgg is associated mainly with early adenomas and may thus constitute an early marker for CRC screening. Sgg has been described as a normal inhabitant of the rumen of herbivores and in the digestive tract of birds. It is more rarely detected in human intestinal tract (2.5–15%). Recent molecular analyses indicate possible zoonotic transmission of Sgg. Thanks to the development of a genetic toolbox and to comparative genomics, a number of factors that are important for Sgg pathogenicity have been identified. This review will highlight the role of Sgg pili in host colonization and how their phase-variable expression contributes to mitigate the host immune responses and finally their use as serological diagnostic tool. We will then present experimental data addressing the core question whether Sgg is a cause or consequence of CRC. We will discuss a few recent studies examining the etiological versus non-etiological participation of Sgg in colorectal cancer with the underlying mechanisms.