Parvimonas micra forms a distinct bacterial network with oral pathobionts in colorectal cancer patients.

BACKGROUND: Mounting evidence suggests a significant role of the gut microbiota in the development and progression of colorectal cancer (CRC). In particular, an over-representation of oral pathogens has been linked to CRC. The aim of this study was to further investigate the faecal microbial landscape of CRC patients, with a focus on the oral pathogens Parvimonas micra and Fusobacterium nucleatum. METHODS: In this study, 16S rRNA sequencing was conducted using faecal samples from CRC patients (n = 275) and controls without pathological findings (n = 95). RESULTS: We discovered a significant difference in microbial composition depending on tumour location and microsatellite instability (MSI) status, with P. micra, F. nucleatum, and Peptostreptococcus stomatis found to be more abundant in patients with MSI tumours. Moreover, P. micra and F. nucleatum were associated with a cluster of CRC-related bacteria including Bacteroides fragilis as well as with other oral pathogens such as P. stomatis and various Porphyromonas species. This cluster was distinctly different in the control group, suggesting its potential linkage with CRC. CONCLUSIONS: Our results suggest a similar distribution of several CRC-associated bacteria within CRC patients, underscoring the importance of considering the concomitant presence of bacterial species in studies investigating the mechanisms of CRC development and progression.

Gut Microbiota and Colorectal Cancer: An Umbrella Review of Methodological Trends and Clinical Correlations.

In this umbrella review, we analyze the effect of gut microbiota on the development and progression of colorectal cancer (CRC), a global health challenge. Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) 2020 guidelines, we searched multiple databases for the most relevant systematic reviews and meta-analyses from 2000 to 2023. We identified 20 articles that met our inclusion criteria. The findings include the identification of specific microbiota markers, such as Fusobacterium nucleatum, for potential early diagnosis and improvement of disease treatment. This thorough study not only establishes the connection between microbiota and CRC but also provides valuable knowledge for future research in developing microbiome-centered treatments and preventive methods.

An Atypical Presentation of a Pyogenic Liver Abscess Caused by Fusobacterium nucleatum Post-ruptured Appendix.

A rare formation of a pyogenic liver abscess can be found in patients with a ruptured appendix. Here, we discuss a 49-year-old male with a past medical history significant for drug-induced pancreatitis from metformin, type II diabetes, obesity, and hypertension who presented with right upper quadrant pain. He was diagnosed with a 12.6 cm pyogenic liver abscess. Upon further chart review, the patient had a laparoscopic appendectomy done nine months ago, with the findings of a ruptured appendix. The liver abscess cultures grewFusobacterium nucleatum - a common culprit of acute appendicitis reported in several case studies and clinical trials. This case report highlights the importance of including appendectomy as an essential part of history-taking and diagnostic differential for pyogenic liver abscesses.

Unraveling a Unique Encounter of Fusobacterium nucleatum With Empyema: A Case Report and Review of Literature.

We report a case of Fusobacterium nucleatum (F. nucleatum) empyema in a 34-year-old male with no significant past medical history or obvious risk factors who presented with shortness of breath and chest pain. His imaging showed complicated parapneumonic effusion which grew F. nucleatum. He was started on piperacillin-tazobactam. The patient's clinical condition deteriorated despite initial therapeutic efforts, leading to escalated antibiotic therapy and further investigations. The patient's subsequent clinical course included pigtail catheter placement with drainage of fluid requiring tpa and dornase alpha, leading to significant improvement and eventual discharge on oral amoxicillin-clavulanic acid.

Fusobacterium nucleatum: More Than Just an Oral Anaerobe.

Fusobacterium nucleatum is a strict anaerobe that is indigenous to the human oral cavity, where it coexists with more than 500 other species. It is associated with paranasal sinus, odontogenic, and pulmonary infections. In literature, cases of Fusobacterium nucleatum are rare. Here we report a case of a patient with multiple brain abscesses caused by Fusobacterium nucleatum. This case report looks to assist clinicians in determining the true etiology of this organism, which can change patient management based on the current literature review and similar case studies.

Fusobacterium Bacteremia Causing Hepatic Abscess in a Patient With Diverticulitis.

Fusobacterium, a gram-negative non-spore-forming anaerobe, is a common inhabitant of the oral cavity; however, it is not typically found in other organ systems. The occurrence of a hepatic abscess associated with this organism is rare. We present a patient with recurrent diverticulitis with left upper quadrant abdominal pain, and abdominal imaging revealed a hepatic abscess in addition to sigmoid diverticulitis. Further investigations led to an unusual culprit; Fusobacterium nucleatum.

Plasma Microbial Cell-Free DNA (CF-DNA) Next-Generation Sequencing in Diagnosing Intracranial Abscesses: Pathophysiology and a Scoping Review of the Literature.

Plasma microbial cell-free DNA (cf-DNA) from next-generation sequencing (NGS) provides improved sensitivity and specificity compared to standard microbial blood cultures. cf-DNA sequencing also has an improved turnaround time (TAT) and allows quicker commencement of antibiotics in life-threatening infections such as a brain abscess. Brain abscesses carry significant morbidity and mortality. Empiric treatment and management are critical in improving functional neurological outcomes. Reported here is the case of a severe central nervous system (CNS) infection with multiple ring-enhancing lesions seen throughout the cerebrum on magnetic resonance imaging (MRI). Standard microbial blood cultures were inconclusive and definitive identification of the pathogen was achieved through microbial cf-DNA NGS.  Brain abscesses develop in four distinct phases: early cerebritis, late cerebritis, early capsule formation, and late capsule formation. The pathogenesis of cerebral abscess involves direct parenchymal inflammation of the pathogen, the recruitment of inflammatory CNS cell types (microglia, inflammatory astrocytes, etc), and the chemotaxis of immune cells. cf-DNA is released into the bloodstream in response to pathogen opsonization and immune-mediated cell death. A scoping literature review includes cases of intracranial abscesses diagnosed via cf-DNA NGS.

Emphysematous Cholecystitis Secondary to Fusobacterium nucleatum.

Fusobacterium nucleatum may be implicated in cases of emphysematous cholecystitis (EC) and carries a high mortality risk, especially in individuals with heart disease, renal insufficiency, and underlying malignancy. Fusobacterium infections are rarely detected in the setting of cholecystitis possibly due to the difficulty with properly culturing the bacteria. We describe a case of a patient with EC in whom blood cultures were positive for growth of F. nucleatum in one of two samples. The patient was treated with empiric antibiotic therapy consisting of metronidazole and cefepime. In patients with EC and negative cultures, it is possible that they may have an undetected infection with fusobacteria, which carries a high mortality risk. As such, clinicians should maintain a high degree of suspicion of obligate anaerobic infection in patients who have negative blood culture for growth in the setting of EC and consider continuation of adequate antimicrobial coverage.