A Rare Twist of the Forgotten Disease: A Case of Fusobacterium necrophorum Sepsis with Portomesenteric Thrombosis and a Review of the Literature

Bacteria in the blood of healthy stray dogs infested by ticks in northern Mexico

Objective

The objectives of this study were to determine the richness, abundance, and diversity of bacteria in stray dogs (Canis lupus familiaris) infested by ticks in Comarca Lagunera, northern Mexico, and to establish their pathogenic and or/zoonotic potential.

Materials and Methods

Blood samples from 12 dogs were collected, and their deoxyribonucleic acid was extracted. The V3-V4 region of the 16S ribosomal ribunocleic acid gene was amplified by polymerase chain reaction. Next-generation sequencing (NGS) was performed on a MiSeq Illumina platform, and the data were analyzed using quantitative insights into microbial ecology.

Results

The operational taxonomic units resulted in 23 phyla, 54 classes, 89 orders, 189 families, 586 genera, and 620 bacterial species; among them, 64 species and/or bacterial genera with pathogenic or zoonotic potential were identified, some of which have been reported in the literature as relevant to public health (Anaplasma phagocytophilum, Brucella spp., Clostridium spp., Corynebacterium affermentants, Cutibacterium spp., Dietzia spp., Ehrlichia canis, Fusobacterium necrophorum, Leptotrichia spp., Mycobacterium spp., Paracoccus spp., and Roseomonas gilardii).

Conclusion

This research offers relevant information on the prevalence of tick-borne diseases as well as other potential zoonotic diseases in the blood of stray dogs parasitized by ticks in northern Mexico. New molecular biology and massive NGS techniques may play an important role in the study and documentation of bacterial profiles from animals in close proximity to humans.

Gastrointestinal Variant of Lemierre Syndrome due to Fusobacterium nucleatum: A Case Report

Introduction

Pyogenic liver abscess is a noteworthy health concern in North America, characterized by a mortality rate ranging from 2 to 12%. This condition is often polymicrobial, with Streptococcus species and Escherichia coli as the predominant causal pathogens in Western countries. Fusobacterium species, typically commensals of gastrointestinal, genital, and oral flora, have been implicated in the rare formation of tonsillar abscesses and Lemierre syndrome, including its gastrointestinal variant known as pylephlebitis.

Case Presentation

We present the case of an immunocompetent male with a 2-week history of abdominal distention and pain. Abdominal magnetic resonance imaging revealed multiseptated cystic hepatic masses and portal vein thrombosis. A subsequent liver biopsy confirmed Fusobacterium nucleatum etiology. The patient was initiated on intravenous cefepime and oral metronidazole antibiotics. Unfortunately, the patient succumbed to cardiac arrest before a final diagnosis could be established.

Conclusion

Fusobacterium species-associated liver abscess, coupled with the rare gastrointestinal variant of Lemierre syndrome (pylephlebitis), poses a significant mortality risk. This case underscores the rarity and clinical challenges associated with these conditions. Increased awareness among clinicians is crucial for early diagnosis and prompt intervention, potentially improving outcomes in such cases.

Fusobacterium bacteremia presenting with inferior mesenteric vein thrombosis

Isolated mesenteric vein thrombosis associated with Fusobacterium is rare. Physicians should be aware regarding the association of Fusobacterium with thrombosis at various sites.

Suppurative Thrombosis of the Portal Vein (Pylephlebits): A Systematic Review of Literature

Suppurative portal vein thrombosis (pylephlebitis) is an uncommon condition usually associated with an intra-abdominal infection or inflammatory process. In this study, we aimed to synthesize data on previously published cases according to the PRISMA guidelines. A total of 103 patients were included. Patients were more commonly male (71.8%) and had a mean age of 49 years. The most common infection associated with pylephlebitis was diverticulitis (n = 29, 28.2%), and Escherichia coli was the most isolated pathogen (n = 21, 20.4%). Blood cultures were positive in 64 cases (62.1%). The most common site of thrombosis was the main portal vein (PV) in 59 patients (57.3%), followed by the superior mesenteric vein (SMV) in 40 patients (38.8%) and the right branch of the PV in 30 patients (29.1%). Sepsis developed in 60 patients (58.3%). The mortality rate in our review was 8.7%, and independent risk factors for mortality were the presence of pertinent comorbidities (OR 5.5, p = 0.02), positive blood cultures (OR 2.2, p = 0.02), and sepsis (OR 17.2, p = 0.049).

Fusobacterium necrophorum Promotes Apoptosis and Inflammatory Cytokine Production Through the Activation of NF-κB and Death Receptor Signaling Pathways

Fusobacterium necrophorum can cause liver abscess, foot rot in ruminants, and Lemire syndrome in humans, Also, its virulence factors can induce the apoptosis of macrophages and neutrophils. However, the detailed mechanism has not been fully clarified. This study investigated the mechanisms of apoptosis and inflammatory factor production in F. necrophorum–induced neutrophils and macrophages (RAW246.7). After infection of macrophages with F. necrophorum, 5-ethynyl-2’-deoxyuridine labeling assays indicated that F. necrophorum inhibited macrophage proliferation in a time- and dose-dependent manner. Hoechst staining and DNA ladder assays showed significant condensation of the nucleus and fragmentation of genomic DNA in F. necrophorum–infected macrophages, Annexin V (FITC) and propidium iodide (PI) assay confirmed the emergence of apoptosis in the macrophages and sheep neutrophils with F. necrophorum compared with the control. The group with significant apoptosis was subjected to RNA sequencing (RNA-Seq), and the sequencing results revealed 2581 up– and 2907 downregulated genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis of the differentially expressed genes showed that F. necrophorum drove apoptosis and production of inflammatory factors by activating genes related to the Nuclear Factor-κB (NF-κB) and death receptor pathways. Meanwhile, quantitative reverse transcription PCR and Western blot validation results were consistent with the results of transcriptome sequencing analysis. In conclusion, F. necrophorum induced apoptosis and production of pro-inflammatory factors through the NF-κB and death receptor signaling pathway, providing a theoretical basis for further mechanistic studies on the prevention and control of F. necrophorum disease treatment.

Pylephlebitis Caused by Fusobacterium nucleatum in a Septuagenarian Healthy Caucasian Male: Atypical Presentation of Lemierre’s Syndrome

Lemierre's syndrome (LS) is characterized by thrombophlebitis of the internal jugular vein caused primarily by Fusobacterium necrophorum. LS is usually suspected in fit young adults with prolonged or prior pharyngeal infection. Atypical Lemierre's syndrome is commonly defined as Fusobacterium-associated thrombophlebitis outside the head-neck veins and usually occurs in older patients than typical Lemierre's syndrome. Here we present a case of atypical LS in a septuagenarian healthy Caucasian male with no prior history of pharyngitis and in whom both computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated partial portal vein thrombosis associated with Fusobacterium nucleatum. This case report confirms previous reports of Fusobacterium nucleatum-associated LS variants presenting with abdominal vein thrombosis and illustrates clinical recovery after a combination of anticoagulation and antibiotic therapy.