China
Africa
Explore chapters and articles related to this topic
The gastrointestinal system
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
Sharon J. White, Francis A. Carey
Necrotizing periodontal diseases include necrotizing gingivitis (NG) and necrotizing periodontitis (NP). These may occur in patients who are both chronically and/or severely compromised (e.g. immunosuppressed or severely malnourished) or patients who are temporarily and/or moderately compromised (such as those who smoke or are stressed). NG typically occurs in young adults and presents as painful, ulceration, and necrosis of the interdental papillae and halitosis. The condition involves the formation of an anaerobic fuso-spirochaetal complex including Fusobacterium nucleatum and Treponema vincentii among others, and responds to improved oral hygiene and appropriate anti-microbial therapy. In contrast, the disease in developing countries occurs most often in malnourished children and, if left untreated, can spread leading to extensive necrosis of orofacial tissue – ‘cancrum oris’ – and may be fatal. HIV infection may also present as necrotizing periodontal conditions. Periodontal disease may arise as a manifestation of systemic disease such as haematological disorders or genetic disorders, e.g. cyclic neutropenia or Ehlers–Danlos syndrome. There is emerging evidence which supports links between periodontal disease and acquired systemic conditions such as diabetes, and cardiovascular disease.
The Microbiome – Role in Personalized Medicine
Published in David Perlmutter, The Microbiome and the Brain, 2019
Over the past five years, overwhelming evidence has been published outlining a strong connection between disturbances of the microbiome and various immunometabolic diseases.69 In cancer therapy, it is now known that there are responders and non-responders to PD-1 targeted immunotherapy, and response status is influenced by the composition of an individual’s microbiome. This finding suggests that the intestinal microbiota should be considered when assessing therapeutic intervention.70,71 A 2018 study reported that the abundance of certain bacterial species in the microbiome – Bifidobacterium longum, Collinsella aerofaciens, and Enterococcus faecium – was found to be associated with responders to anti-PD-1 efficacy in metastatic melanoma patients.72 Another recent publication stated that the bacterium Fusobacterium nucleatum is a chemoresistance mediator in colorectal cancer therapy.73 In lung cancer, the commensal microbiota is closely correlated with chronic inflammation and lung adenocarcinoma through the activation of lung-resident gamma delta T cells.74
Where Cancer and Bacteria Meet
Published in Ananda M. Chakrabarty, Arsénio M. Fialho, Microbial Infections and Cancer Therapy, 2019
Alexandra Merlos, Ricardo Perez-Tomás, José López-López, Miguel Viñas
Anaerobic gram-negative bacteria have also been implicated in several forms of cancer. One of the best studied species is Fusobacterium nucleatum, representative of the genus Fusobacterium. This spindle-shaped strict anaerobe is commonly found both in the oral cavity and in the gut. F. nucleatum induces permanent chronic inflammation in the colon and has thus been associated with colorectal cancer. However, the mechanism is still unclear. Rubinstein et al. [15] showed that F. nucleatum adheres to and invades tissues, which activates inflammatory responses and stimulates the growth of colorectal cells. The underlying mechanism involves the interaction of colonic cells with the bacterial adhesin FadA, which binds to E-cadherin. The same authors showed 100 times higher fadA gene levels in the colon tissue from patients with adenomas and adenocarcinomas than in healthy individuals, thus identifying FadA as a potential diagnostic and therapeutic target for colorectal cancer.
Mapping the colorectal tumor microbiota
Published in Gut Microbes, 2021
CL Murphy, M Barrett, P Pellanda, S Killeen, M McCourt, E Andrews, M O’ Riordain, F Shanahan, Pw O’Toole
Samples were pooled based on biopsy site and pairwise analysis was performed for each sample pair within the biopsy site. Differential ASV abundance was not detected with respect to anatomical site when we applied paired sample Wilcoxon test with Benjamini-Hochberg adjustment for multiple comparisons (Supplementary table 6). We next utilized DESeq2 which has been demonstrated to be sensitive when applied to small sample sizes.33,34 We identified a number of differentially abundant ASVs between sample-sites while controlling for which patient the biopsy originated from (Figure 2). Notably, a number of ASVs assigned to the oral species Fusobacterium nucleatum, were observed to be enriched on tumor samples relative to undiseased disease (distal normal and proximal normal). In particular, Seq 31 was identified to be enriched in 5/5 proximal tumor biopsies relative to a healthy distal biopsy and 4/5 tumor biopsies relative to the healthy distal biopsy.
Therapeutic methods of gut microbiota modification in colorectal cancer management – fecal microbiota transplantation, prebiotics, probiotics, and synbiotics
Published in Gut Microbes, 2020
Karolina Kaźmierczak-Siedlecka, Agnieszka Daca, Mateusz Fic, Thierry van de Wetering, Marcin Folwarski, Wojciech Makarewicz
Gut microbiota may be used as a prognostic biomarker to assess overall survival (OS), in patients with colorectal cancer as shown in a pilot study conducted by Wei et al.80 A high abundance of Fusobacterium nucleatum and Bacteroides fragilis was related to worse OS after the surgical procedure. On the contrary, a high abundance of Faecalibacterium prausnitzii was associated with a better OS. This study confirms the hypothesis that Faecalibacterium prausnitzii plays a protective role in this situation. In addition, clinical trials have revealed that there is a low abundance of Faecalibacterium prausnitzii in patients with ulcerative colitis.80 The beneficial effects of Faecalibacterium prausnitzii are thought to be mediated mainly through its high capacity to induce IL-10 secretion in humans. Due to these anti-inflammatory properties, it may provide protection against colitis.81
The pathogenic microbial flora and its antibiotic susceptibility pattern in odontogenic infections
Published in Drug Metabolism Reviews, 2019
Paul Andrei Tent, Raluca Iulia Juncar, Florin Onisor, Simion Bran, Antonia Harangus, Mihai Juncar
The bacterial strain that is most frequently isolated from aerobic flora is Streptococcus, followed by Staphylococcus aureus (Hunt and Meyer 1983; Har-El et al. 1994; Hawkey 2000, Peltroche et al. 2000; Storoe et al. 2001; Stefanopoulos and Kolokotronis 2004; Chow 2005; Rega et al. 2006; Warnke et al. 2008; Skucaite et al. 2010; Singh et al. 2014; Rastenienė et al. 2015; Zirk et al. 2016; Shakya et al. 2018). However, other authors most frequently isolate Staphylococcus aureus (Smith et al. 2001; Walia et al. 2014; Heim et al. 2017). Other bacteria belonging to aerobic flora have been isolated in low proportions. We mention the following: Corynebacterium spp., Proteus vulgaris, Haemophilus spp, Neisseria spp, Klebsiella pneumoniae (Warnke et al. 2008; Skucaite et al. 2010; Singh et al. 2014; Rastenienė et al. 2015; Zirk et al. 2016; Shakya et al. 2018). From anaerobic flora, Prevotella intermedia has been isolated the most frequently (Kannangara et al. 1980; Heimdahl and Nord 1985; Berini and Gay Escoda 1999; Herrera et al. 2000; Huang et al. 2006; Warnke et al. 2008; Poeschl et al. 2010; Sánchez et al. 2011; Chunduri et al. 2012; Zirk et al. 2016; Heim et al. 2017; Plum et al. 2018). In contrast, other authors most frequently isolate Fusobacterium nucleatum (Boyanova et al. 2006; Shakya et al. 2018), Bacteroides fragillis (Har-El et al. 1994; Storoe et al. 2001; Gbolahan et al. 2011; Rastenienė et al. 2015) or Peptostreptococcus (Kuriyama et al. 2000; Singh et al. 2014).