China
Africa
Explore chapters and articles related to this topic
Unexplained Fever In Infectious Diseases: Section 2: Commonly Encountered Aerobic, Facultative Anaerobic, And Strict Anaerobic Bacteria, Spirochetes, And Parasites
Published in Benedict Isaac, Serge Kernbaum, Michael Burke, Unexplained Fever, 2019
Bacteremia with Bacteroides fragilis may also be severe, the main clinical features being: abdominal abscesses, jaundice, thrombophlebitis and septic metastases (especially pulmonary). Table 4 lists the infections due to nonsporing endogenous anaerobes. Most of these infections are associated with fever.48,49
Pharmacokinetic/Pharmacodynamic Modeling of Antibiotics
Published in Hartmut Derendorf, Günther Hochhaus, Handbook of Pharmacokinetic/Pharmacodynamic Correlation, 2019
Arno Nolting, Hartmut Derendorf
Flaherty et al.53 evaluated pharmacokinetics and serum inhibitory effects of clindamycin in healthy subjects for different dosing regimens (600 mg q6h, 900 mg q8h, and 1200 mg q12h). Serial blood samples were used to determine the pharamcokinetics and serum inhibitory effects against Bacteroides fragilis ATCC 25285. Serum samples were serially diluted with heat-inactivated human serum and inoculated with B. fragilis. After overnight incubation, the highest dilution was determined that prevented visible growth (serum inhibitory titer). Reciprocal values of serum inhibitory titers were plotted vs. time (Figure 17). The areas under these serum inhibitory curves (AUIC) were calculated and used to compare the efficacy of the three dosing regimens. AUIC values for 24 h did not vary significantly (697 ± 290, 726 ± 217, and 635 ± 164 for the 600-, 900-, and 1200-mg dosing regimens, respectively). The authors, therefore, suggested a less frequent administration of clindamycin (every 8 or 12 h) as more convenient and more cost-effective.
Peritonitis (General Considerations)
Published in Peter Sagar, Andrew G. Hill, Charles H. Knowles, Stefan Post, Willem A. Bemelman, Patricia L. Roberts, Susan Galandiuk, John R.T. Monson, Michael R.B. Keighley, Norman S. Williams, Keighley & Williams’ Surgery of the Anus, Rectum and Colon, 2019
Donald E. Fry, Susan Galandiuk
Despite the large number of bacterial species that can be cultured or genetically identified in the colon, only a limited number are recognised as having clinical participation in peritonitis. E. coli is the most common gram-negative rod with Klebsiella sp., Enterobacter sp. and Proteus mirabilis being occasionally cultured.7 The Enterococcus sp. are the most common of the gram-positive cocci to be identified. Many anaerobic species including Bacteroides sp., Lactobacillus sp., Clostridium sp., Bifidobacterium sp. and many others may be seen. Amongst all obligate anaerobes, Bacteroides fragilis is of greatest pathophysiologic significance8 because of its virulence factors and antimicrobial resistance.
“Driver-passenger” bacteria and their metabolites in the pathogenesis of colorectal cancer
Published in Gut Microbes, 2021
Marion Avril, R. William DePaolo
Bacteroides fragilis is a common gram-negative anaerobic bacterium belonging to the Bacteroidetes phylum. B. fragilis has two subgroups, the enterotoxigenic strains (ETBF) that possess the bft gene encoding the B. fragilis toxin (BFT or fragilysin), while the nontoxigenic strains (NTBF) do not. ETBF has been implicated in diarrhea41 and is considered oncogenic under certain circumstances due the actions of BFT which can induce DNA damage and inflammation in vivo.18,42 BFT is a metalloproteinase and has been shown to rapidly alter the structure and function of colonic epithelial cells, including the cleavage of the tumor suppressor protein, E-cadherin. Once cleaved this triggers β-catenin/Wnt signaling leading to permeability of the intestinal barrier. One of the molecular mechanisms in which ETBF triggers colitis and induces colon tumorigenesis in multiple intestinal neoplasia (Min) mice, is via the activation of signal transducer and activator of transcription 3 (STAT3) and induction of T-helper type-17 (TH17) T cell responses.
Elucidating the gut microbiota composition and the bioactivity of immunostimulatory commensals for the optimization of immune checkpoint inhibitors
Published in OncoImmunology, 2020
Romain Daillère, Bertrand Routy, Anne-Gaëlle Goubet, Alexandria Cogdill, Gladys Ferrere, Carolina Alves-Costa Silva, Aurélie Fluckiger, Pierre Ly, Yacine Haddad, Eugenie Pizzato, Cassandra Thelemaque, Marine Fidelle, Marine Mazzenga, Maria Paula Roberti, Cléa Melenotte, Peng Liu, Safae Terrisse, Oliver Kepp, Guido Kroemer, Laurence Zitvogel, Lisa Derosa
The first bacterial species known to harbor “zwitterionic” peptides capable of engaging CD4+ T cell receptors was Bacteroides fragilis.80–82 B. fragilis was very effective in boosting immune responses primed in the setting of sarcoma tumors treated with anti-CTLA4 Ab23 as well as colon carcinoma treated with oxaliplatin-based immunogenic chemotherapy.51 Antibiotics blunted the anticancer efficacy of CTLA-4 blockade against various transplantable tumors unless oral supplementation with B. fragilis was performed, which reinstated IL-12-dependent Th1 immune responses. Interestingly, anti-CTLA-4 Abs administered to tumor-bearing avatar mice reconstituted with FMT from melanoma patients foster the overrepresentation of distinct Bacteroides spp. (Bacteroides fragilis or Bacteroides thetaiotaomicron) and recapitulated the phenotype of response observed in patient.23 Interestingly, oral supplementation with B. fragilis (as opposed to Fusobacterium nucleatum or Paraprevotella clara) turned chemotherapy-induced tolerogenic ileal apoptosis into immunogenic cell demise capable of eliciting PD1high follicular helper T cells and B cell responses and of promoting the efficacy of anti-PD1 Abs against established colon cancers.51 Hence, the ileal microbiota enriched in commensals playing the role of adjuvant for ileal apoptosis triggered TFH and the efficacy of PD-1 blockade, even in tumors devoid of neoantigens.
Eravacycline for the treatment of complicated intra-abdominal infections
Published in Expert Review of Anti-infective Therapy, 2019
Philippe Montravers, Nathalie Zappella, Alexy Tran-Dinh
In vitro studies have reported interesting activity against several panels of anaerobic strains. In a study evaluating 143 clinical isolates including 23 Bacteroides fragilis strains, eravacycline was four- to eight-fold more active than tigecycline [41]. In a larger study comprising 335 different Gram-negative and Gram-positive anaerobic clinical isolates and comparing the activity of eravacycline against 11 antibiotics, eravacycline demonstrated in vitro activity against all isolates with better susceptibility results than those reported with tigecycline: B. fragilis group (MIC50/90 0.25/1 µg/mL versus 1/8 µg/mL for eravacycline and tigecycline, respectively), Prevotella spp. (MIC50/90 0.25/0.5 versus 0.5/1 µg/mL), Fusobacterium spp. (MIC50/90 0.03/0.12 versus 0.12/0.5 µg/mL), Clostridium perfringens (MIC50/90 0.12/1 versus 0.5/2 µg/mL), and Peptostreptococcus spp. (MIC50/90 0.12/0.25 versus 0.25/0.25 µg/mL) [42]. Eravacycline has also demonstrated in vitro activity against C. difficile (MIC50/90 0.06/0.12 µg/mL) and against anaerobic strains expressing tetracycline-resistance determinants and resistance to carbapenems and/or beta-lactam/beta-lactamase inhibitors [42].