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Journal of Microbiology, Immunology,... Aug 2020Lemierre's syndrome, also known as post-anginal septicemia or necrobacillosis, is characterized by bacteremia, internal jugular vein thrombophlebitis, and metastatic... (Review)
Review
Lemierre's syndrome, also known as post-anginal septicemia or necrobacillosis, is characterized by bacteremia, internal jugular vein thrombophlebitis, and metastatic septic emboli secondary to acute pharyngeal infections. Modern physicians have "forgotten" this disease. The most common causative agent of Lemierre's syndrome is Fusobacterium necrophorum, followed by Fusobacterium nucleatum and anaerobic bacteria such as streptococci, staphylococci, and Klebsiella pneumoniae. The causative focus mostly originated from pharyngitis or tonsillitis, accounting for over 85% of the cases of Lemierre's syndrome. Pneumonia or pleural empyema is the most common metastatic infection in Lemierre's syndrome. Antimicrobial therapy should be prescribed for 3-6 weeks. The treatment regimens include metronidazole and β-lactam antibiotics. In recent years, the antibiotic stewardship program has resulted in decreased antibiotic prescription for upper respiratory tract infections. The incidence of Lemierre's syndrome has increased over the past decade. F. necrophorum is an underestimated cause of acute pharyngitis or tonsillitis. A high index of suspicion is required for the differential diagnosis of acute tonsillopharyngitis with persistent neck pain and septic syndrome.
Topics: Anti-Bacterial Agents; Bacteria; Bacteria, Anaerobic; Communicable Diseases, Emerging; Fusobacterium necrophorum; Humans; Lemierre Syndrome; Pharyngitis; Sepsis
PubMed: 32303484
DOI: 10.1016/j.jmii.2020.03.027 -
Nature Reviews. Urology Apr 2020The female reproductive tract (FRT), similar to other mucosal sites, harbours a site-specific microbiome, which has an essential role in maintaining health and... (Review)
Review
The female reproductive tract (FRT), similar to other mucosal sites, harbours a site-specific microbiome, which has an essential role in maintaining health and homeostasis. In the majority of women of reproductive age, the microbiota of the lower FRT (vagina and cervix) microenvironment is dominated by Lactobacillus species, which benefit the host through symbiotic relationships. By contrast, the upper FRT (uterus, Fallopian tubes and ovaries) might be sterile in healthy individuals or contain a low-biomass microbiome with a diverse mixture of microorganisms. When dysbiosis occurs, altered immune and metabolic signalling can affect hallmarks of cancer, including chronic inflammation, epithelial barrier breach, changes in cellular proliferation and apoptosis, genome instability, angiogenesis and metabolic dysregulation. These pathophysiological changes might lead to gynaecological cancer. Emerging evidence shows that genital dysbiosis and/or specific bacteria might have an active role in the development and/or progression and metastasis of gynaecological malignancies, such as cervical, endometrial and ovarian cancers, through direct and indirect mechanisms, including modulation of oestrogen metabolism. Cancer therapies might also alter microbiota at sites throughout the body. Reciprocally, microbiota composition can influence the efficacy and toxic effects of cancer therapies, as well as quality of life following cancer treatment. Modulation of the microbiome via probiotics or microbiota transplant might prove useful in improving responsiveness to cancer treatment and quality of life. Elucidating these complex host-microbiome interactions, including the crosstalk between distal and local sites, will translate into interventions for prevention, therapeutic efficacy and toxic effects to enhance health outcomes for women with gynaecological cancers.
Topics: Anti-Infective Agents; Bacteria, Anaerobic; Carcinogenesis; Cervix Uteri; Dysbiosis; Estrogens; Fallopian Tubes; Female; Gastrointestinal Microbiome; Genital Neoplasms, Female; Genitalia, Female; Humans; Lactobacillus; Microbiota; Ovary; Probiotics; Uterus; Vagina
PubMed: 32071434
DOI: 10.1038/s41585-020-0286-z -
Cancer Medicine Sep 2020Bacteria identified in the oral cavity are highly complicated. They include approximately 1000 species with a diverse variety of commensal microbes that play crucial... (Review)
Review
Bacteria identified in the oral cavity are highly complicated. They include approximately 1000 species with a diverse variety of commensal microbes that play crucial roles in the health status of individuals. Epidemiological studies related to molecular pathology have revealed that there is a close relationship between oral microbiota and tumor occurrence. Oral microbiota has attracted considerable attention for its role in in-situ or distant tumor progression. Anaerobic oral bacteria with potential pathogenic abilities, especially Fusobacterium nucleatum and Porphyromonas gingivalis, are well studied and have close relationships with various types of carcinomas. Some aerobic bacteria such as Parvimonas are also linked to tumorigenesis. Moreover, human papillomavirus, oral fungi, and parasites are closely associated with oropharyngeal carcinoma. Microbial dysbiosis, colonization, and translocation of oral microbiota are necessary for implementation of carcinogenic functions. Various underlying mechanisms of oral microbiota-induced carcinogenesis have been reported including excessive inflammatory reaction, immunosuppression of host, promotion of malignant transformation, antiapoptotic activity, and secretion of carcinogens. In this review, we have systemically described the impact of oral microbial abnormalities on carcinogenesis and the future directions in this field for bringing in new ideas for effective prevention of tumors.
Topics: Alphapapillomavirus; Bacteria, Aerobic; Bacteria, Anaerobic; Bacterial Translocation; Cell Transformation, Neoplastic; Disease Progression; Dysbiosis; Firmicutes; Fungi; Fusobacterium nucleatum; Humans; Immune Tolerance; Microbiota; Mouth; Neoplasms; Oropharyngeal Neoplasms; Porphyromonas gingivalis
PubMed: 32638533
DOI: 10.1002/cam4.3206 -
Nature Nov 2021Antibiotics are used to fight pathogens but also target commensal bacteria, disturbing the composition of gut microbiota and causing dysbiosis and disease. Despite this...
Antibiotics are used to fight pathogens but also target commensal bacteria, disturbing the composition of gut microbiota and causing dysbiosis and disease. Despite this well-known collateral damage, the activity spectrum of different antibiotic classes on gut bacteria remains poorly characterized. Here we characterize further 144 antibiotics from a previous screen of more than 1,000 drugs on 38 representative human gut microbiome species. Antibiotic classes exhibited distinct inhibition spectra, including generation dependence for quinolones and phylogeny independence for β-lactams. Macrolides and tetracyclines, both prototypic bacteriostatic protein synthesis inhibitors, inhibited nearly all commensals tested but also killed several species. Killed bacteria were more readily eliminated from in vitro communities than those inhibited. This species-specific killing activity challenges the long-standing distinction between bactericidal and bacteriostatic antibiotic classes and provides a possible explanation for the strong effect of macrolides on animal and human gut microbiomes. To mitigate this collateral damage of macrolides and tetracyclines, we screened for drugs that specifically antagonized the antibiotic activity against abundant Bacteroides species but not against relevant pathogens. Such antidotes selectively protected Bacteroides species from erythromycin treatment in human-stool-derived communities and gnotobiotic mice. These findings illluminate the activity spectra of antibiotics in commensal bacteria and suggest strategies to circumvent their adverse effects on the gut microbiota.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Bacteria, Anaerobic; Bacteroides; Clostridioides difficile; Dicumarol; Erythromycin; Feces; Female; Gastrointestinal Microbiome; Germ-Free Life; Humans; Macrolides; Male; Mice; Microbiota; Symbiosis; Tetracyclines
PubMed: 34646011
DOI: 10.1038/s41586-021-03986-2 -
The Journal of Biological Chemistry Mar 2020An early exposure to lipid biochemistry in the laboratory of Konrad Bloch resulted in a fascination with the biosynthesis, structures, and functions of bacterial lipids....
An early exposure to lipid biochemistry in the laboratory of Konrad Bloch resulted in a fascination with the biosynthesis, structures, and functions of bacterial lipids. The discovery of plasmalogens (1-alk-1'-enyl, 2-acyl phospholipids) in anaerobic Gram-positive bacteria led to studies on the physical chemistry of these lipids and the cellular regulation of membrane lipid polymorphism in bacteria. Later studies in several laboratories showed that the formation of the alk-1-enyl ether bond involves an aerobic process in animal cells and thus is fundamentally different from that in anaerobic organisms. Our work provides evidence for an anaerobic process in which plasmalogens are formed from their corresponding diacyl lipids. Studies on the roles of phospholipases in revealed distinctions between its phospholipases and those previously discovered in other bacteria and showed how the enzymes are uniquely fitted to the intracellular lifestyle of this significant human pathogen.
Topics: Anaerobiosis; Bacteria, Anaerobic; Fatty Acids; Gram-Positive Bacteria; Lipids; Phosphatidylethanolamines; Plasmalogens
PubMed: 32221031
DOI: 10.1074/jbc.X120.013022 -
International Journal of Infectious... Jan 2021For decades, the term "anti-anaerobic" has been commonly used to refer to antibiotics exhibiting activity against anaerobic bacteria, also designated as anaerobes. This... (Review)
Review
For decades, the term "anti-anaerobic" has been commonly used to refer to antibiotics exhibiting activity against anaerobic bacteria, also designated as anaerobes. This term is used in various situations ranging from infections associated with well-identified pathogens like Clostridioides difficile, or Fusobacterium necrophorum in Lemierre's syndrome, that require specific antibiotic treatments to polymicrobial infections generally resulting from the decreased permeability of anatomical barriers (e.g., intestinal translocation and stercoral peritonitis) or infectious secondary localizations (e.g., brain abscess and infectious pleurisy). In these cases, the causal bacteria generally remain unidentified and the antimicrobial treatment is empirical. However, major progress in the knowledge of human bacterial microbiotas in the last 10 years has shown how diverse are the species involved in these communities. Here, we sought to reappraise the concept of anti-anaerobic spectrum in the light of recent advances in the microbiota field. We first highlight that the term anaerobic itself does not represent the tremendous diversity of the bacteria it spans, and then we stress that the antibiotic susceptibility profiles for most anaerobic bacteria remain unaddressed. Furthermore, we provide examples challenging the relevance of the "anti-anaerobic" spectrum from a clinical and ecological perspective.
Topics: Anaerobiosis; Animals; Anti-Bacterial Agents; Bacteria, Anaerobic; Humans; Microbiota; Terminology as Topic
PubMed: 33127500
DOI: 10.1016/j.ijid.2020.10.052