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International Journal of Medical... 2012In this study hypothesing the translocation of oral bacteria from oropharynx into the middle ear cavity may be involved in the pathogenesis of otitis media with effusion...
OBJECTIVE
In this study hypothesing the translocation of oral bacteria from oropharynx into the middle ear cavity may be involved in the pathogenesis of otitis media with effusion (OME), we aimed to investigate the presence and similarity of Fusobacterium nucleatum and Treponema denticola in saliva, nasopharyngeal secretion and the middle ear effusion samples from the children with OME.
METHODS
Totally 20 children with OME undergoing myringotomy and ventilation tube placement were attended. Stimulated saliva samples were collected after otorhinolaryngological and oral examinations were done. The middle ear effusion and nasopharyngeal secretions were collected during the operations. The presence of F. nucleatum and T. denticola were detected using 16SrRNA-based PCR. The clonal similarities of the bacteria were detected in the samples which the same bacteria had been detected in each samples of the same child. After DNA sequencing, clonal similarity was determined by 16SrRNA gene clone library analysis. The sequences from each clone were compared with similar sequences of reference organisms by FASTA search.
RESULTS
T. denticola was detected only in four (20%) saliva and in one (5%) nasopharyngeal sample. F. nucleatum was detected in 11 (55%) saliva, eight (40%) nasopharyngeal and six (30%) middle ear effusion samples. Sequences from F.nucleatum clones derived from three different anatomic sites within patients were similar in 33% of OME patients, indicating their genetic relatedness.
CONCLUSIONS
Bacteria involved in this process most likely originate from the oropharynx since they show a close genetic relatedness with their oropharyngeal counterparts.
Topics: Bacteria, Anaerobic; Base Sequence; Child; Child, Preschool; DNA Primers; Humans; Mouth; Otitis Media with Effusion; Polymerase Chain Reaction; RNA, Ribosomal, 16S
PubMed: 22606045
DOI: 10.7150/ijms.4382 -
Yonsei Medical Journal Dec 1998While antibiotic resistance among anaerobes continues to increase, the frequency of antimicrobial susceptibility testing for anaerobes is declining. Because anaerobic... (Review)
Review
While antibiotic resistance among anaerobes continues to increase, the frequency of antimicrobial susceptibility testing for anaerobes is declining. Because anaerobic infections are often mixed and detailed bacteriology of the organisms involved may take some time, physicians must institute empiric therapy before susceptibility testing results are available. Also, economic realities and prudent use of resources mandate that careful consideration be given to the necessity for routine susceptibility testing of anaerobic bacteria. Determination of appropriate therapy can be based on published antibiograms; however, since patterns may vary within geographic regions and even within hospitals, it is strongly recommended that each hospital center periodically test their isolates to determine local patterns and detect any pockets of resistance. As a general guide, antibiograms from the last several years of susceptibility testing at the Wadsworth Anaerobe Laboratory are reported.
Topics: Bacteria, Anaerobic; Drug Resistance, Microbial; Humans; Microbial Sensitivity Tests
PubMed: 10097675
DOI: 10.3349/ymj.1998.39.6.495 -
Applied and Environmental Microbiology Apr 2006Microbial communities in the biological filter and waste sludge compartments of a marine recirculating aquaculture system were examined to determine the presence and...
Microbial communities in the biological filter and waste sludge compartments of a marine recirculating aquaculture system were examined to determine the presence and activity of anaerobic ammonium-oxidizing (anammox) bacteria. Community DNA was extracted from aerobic and anaerobic fixed-film biofilters and the anaerobic sludge waste collection tank and was analyzed by amplifying 16S rRNA genes by PCR using anammox-selective and universal GC-clamped primers. Separation of amplified PCR products by denaturing gradient gel electrophoresis and sequencing of the different phylotypes revealed a diverse biofilter microbial community. While Planctomycetales were found in all three communities, the anaerobic denitrifying biofilters contained one clone that exhibited high levels of sequence similarity to known anammox bacteria. Fluorescence in situ hybridization studies using an anammox-specific probe confirmed the presence of anammox Planctomycetales in the microbial biofilm from the denitrifying biofilters, and anammox activity was observed in these biofilters, as detected by the ability to simultaneously consume ammonia and nitrite. To our knowledge, this is the first identification of anammox-related sequences in a marine recirculating aquaculture filtration system, and our findings provide a foundation for incorporating this important pathway for complete nitrogen removal in such systems.
Topics: Ammonia; Aquaculture; Bacteria, Anaerobic; Biofilms; DNA, Ribosomal; Filtration; In Situ Hybridization, Fluorescence; Molecular Sequence Data; Nitrates; Oxidation-Reduction; Polymorphism, Restriction Fragment Length; RNA, Ribosomal, 16S; Seawater; Sequence Analysis, DNA
PubMed: 16597996
DOI: 10.1128/AEM.72.4.2896-2904.2006 -
Anaerobe Feb 2020Studies on the antimicrobial susceptibility profile of anaerobic bacteria are underrepresented in the literature. Within this study we aim to give an extensive overview...
Antimicrobial susceptibility profiles of anaerobic bacteria, isolated from human clinical specimens, within different European and surrounding countries. A joint ESGAI study.
OBJECTIVES
Studies on the antimicrobial susceptibility profile of anaerobic bacteria are underrepresented in the literature. Within this study we aim to give an extensive overview of the differences in antimicrobial susceptibility profiles between different European and surrounding countries.
METHODS
Minimal inhibitory concentration (MIC) data of different antibiotics were collected from 10 participating laboratories, representing an equal number of countries. All MIC's were determined using Etest, according to the protocol used by the participating laboratory. Anaerobic genera represented by at least 10 clinical isolates were included in the study.
RESULTS
Each country tested different antibiotics, sometimes depending on the kind of infection and/or the anaerobic species isolated. All countries tested clindamycin and metronidazole. Resistance rates differed remarkably between the different countries. Especially in Kuwait, resistance was high for all tested antibiotics. Unexpected metronidazole resistance was observed for Finegoldia magna isolates, Peptoniphilus isolates and Eggerthella lenta isolates.
CONCLUSIONS
Due to the extensive differences in antimicrobial susceptibility profile of anaerobic bacteria isolated within different countries, we strongly recommend to perform this kind of study on a regular basis.
Topics: Anti-Bacterial Agents; Bacteria, Anaerobic; Bacterial Infections; Drug Resistance, Bacterial; Europe; Humans; Kuwait; Microbial Sensitivity Tests
PubMed: 31634565
DOI: 10.1016/j.anaerobe.2019.102111 -
European Journal of Biochemistry Oct 1988Many anaerobic bacteria can completely oxidize organic matter to CO2 with either sulfur, sulfate, or protons as electron acceptor. The sulfur-reducing bacteria and one... (Review)
Review
Many anaerobic bacteria can completely oxidize organic matter to CO2 with either sulfur, sulfate, or protons as electron acceptor. The sulfur-reducing bacteria and one genus of sulfate reducers use a modified citric-acid cycle with a novel anaplerotic sequence as pathway of terminal respiration. All other anaerobes use an alternative pathway, in which carbon monoxide dehydrogenase is a key enzyme and in which acetyl-CoA is cleaved into two C1 units at the oxidation level of CH3OH and CO. Thus almost 50 years after the discovery of the citric acid cycle by Hans Krebs in 1937, a second pathway for acetyl-CoA oxidation was found.
Topics: Acetates; Bacteria, Anaerobic; Citric Acid Cycle
PubMed: 3049083
DOI: 10.1111/j.1432-1033.1988.tb14307.x -
Current Biology : CB Oct 2014The human microbiome contains diverse microorganisms, which share and compete for the same environmental niches. A major microbial growth form in the human body is the...
The human microbiome contains diverse microorganisms, which share and compete for the same environmental niches. A major microbial growth form in the human body is the biofilm state, where tightly packed bacterial, archaeal, and fungal cells must cooperate and/or compete for resources in order to survive. We examined mixed biofilms composed of the major fungal species of the gut microbiome, Candida albicans, and each of five prevalent bacterial gastrointestinal inhabitants: Bacteroides fragilis, Clostridium perfringens, Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecalis. We observed that biofilms formed by C. albicans provide a hypoxic microenvironment that supports the growth of two anaerobic bacteria, even when cultured in ambient oxic conditions that are normally toxic to the bacteria. We also found that coculture with bacteria in biofilms induces massive gene expression changes in C. albicans, including upregulation of WOR1, which encodes a transcription regulator that controls a phenotypic switch in C. albicans, from the "white" cell type to the "opaque" cell type. Finally, we observed that in suspension cultures, C. perfringens induces aggregation of C. albicans into "mini-biofilms," which allow C. perfringens cells to survive in a normally toxic environment. This work indicates that bacteria and C. albicans interactions modulate the local chemistry of their environment in multiple ways to create niches favorable to their growth and survival.
Topics: Anaerobiosis; Bacteria, Anaerobic; Biofilms; Candida albicans; Coculture Techniques; Microbiological Techniques
PubMed: 25308076
DOI: 10.1016/j.cub.2014.08.057 -
Annals of the Academy of Medicine,... Jan 2015This retrospective study was performed to evaluate the frequency of anaerobic bacteraemia over a 10-year period, and to provide updated antibiotic susceptibilities for...
INTRODUCTION
This retrospective study was performed to evaluate the frequency of anaerobic bacteraemia over a 10-year period, and to provide updated antibiotic susceptibilities for the more clinically relevant anaerobes causing blood stream infection.
MATERIALS AND METHODS
Data were retrieved from the laboratory information system for the period 2003 to 2012. During this time, blood cultures were inoculated in Bactec™ Plus vials (BD, USA) and continuously monitored in the Bactec™ 9000 blood culture system (BD, USA). Anaerobic organisms were identified using commercial identification kits, predominantly API 20 A (bioMérieux, France) supplemented with Vitek ANC cards (bioMérieux, France) and AN-Ident discs (Oxoid, United Kingdom). A representative subset of isolates were retrieved from 2009 to 2011 and antimicrobial susceptibilities to penicillin, amoxicillin-clavulanate, clindamycin, imipenem, moxifloxacin, piperacillin-tazobactam and metronidazole were determined using the Etest method.
RESULTS
Anaerobes comprised 4.1% of all positive blood culture with 727 obligate anaerobes recovered over the 10-year period, representing a positivity rate of 0.35%. The only significant change in anaerobe positivity rates occurred between 2003 and 2004, with an increase of 0.2%. The Bacteroides fragilis group (45%) were the predominant anaerobic pathogens, followed by Clostridium species (12%), Propioniobacterium species (11%) and Fusobacterium species (6%). The most active in vitro antibiotics were imipenem, piperacillin-tazobactam, amoxicillin-clavulanate and metronidazole, with susceptibilities of 95.0%, 93.3%, 90.8% and 90.8% respectively. Resistance was high to penicillin, clindamycin and moxifl oxacin. However, there were apparent differences for antibiotic susceptibilities between species.
CONCLUSION
This study indicates that the anaerobes comprise a small but constant proportion of bloodstream isolates. Antibiotic resistance was high to some antibiotics, but metronidazole, the beta-lactam/beta-lactamase inhibitors and carbapenems retained good in vitro activity.
Topics: Anti-Bacterial Agents; Bacteremia; Bacteria, Anaerobic; Humans; Microbial Sensitivity Tests; Retrospective Studies; Time Factors
PubMed: 25703492
DOI: No ID Found -
Chemosphere Mar 2017Selenium (Se) nanoparticles are often synthesized by anaerobes. However, anaerobic bacteria cannot be directly applied for bioremediation of contaminated top soil which...
Selenium (Se) nanoparticles are often synthesized by anaerobes. However, anaerobic bacteria cannot be directly applied for bioremediation of contaminated top soil which is generally aerobic. In this study, a selenite-reducing bacterium, Citrobacter freundii Y9, demonstrated high selenite reducing power and produced elemental nano-selenium nanoparticles (nano-Se) under both aerobic and anaerobic conditions. The biogenic nano-Se converted 45.8-57.1% and 39.1-48.6% of elemental mercury (Hg) in the contaminated soil to insoluble mercuric selenide (HgSe) under anaerobic and aerobic conditions, respectively. Addition of sodium dodecyl sulfonate enhanced Hg remediation, probably owing to the release of intracellular nano-Se from the bacterial cells for Hg fixation. The reaction product after remediation was identified as non-reactive HgSe that was formed by amalgamation of nano-Se and Hg. Biosynthesis of nano-Se both aerobically and anaerobically therefore provides a versatile and cost-effective remediation approach for Hg-contaminated surface and subsurface soils, where the redox potential often changes dramatically.
Topics: Aerobiosis; Anaerobiosis; Bacteria, Aerobic; Bacteria, Anaerobic; Biodegradation, Environmental; Mercury; Mercury Compounds; Nanoparticles; Selenium; Selenium Compounds; Soil; Soil Microbiology; Soil Pollutants
PubMed: 28011305
DOI: 10.1016/j.chemosphere.2016.12.020 -
FEMS Microbiology Reviews Dec 1998From recent research it has become clear that at least two different possibilities for anaerobic ammonium oxidation exist in nature. 'Aerobic' ammonium oxidizers like... (Review)
Review
From recent research it has become clear that at least two different possibilities for anaerobic ammonium oxidation exist in nature. 'Aerobic' ammonium oxidizers like Nitrosomonas eutropha were observed to reduce nitrite or nitrogen dioxide with hydroxylamine or ammonium as electron donor under anoxic conditions. The maximum rate for anaerobic ammonium oxidation was about 2 nmol NH4+ min-1 (mg protein)-1 using nitrogen dioxide as electron acceptor. This reaction, which may involve NO as an intermediate, is thought to generate energy sufficient for survival under anoxic conditions, but not for growth. A novel obligately anaerobic ammonium oxidation (Anammox) process was recently discovered in a denitrifying pilot plant reactor. From this system, a highly enriched microbial community with one dominating peculiar autotrophic organism was obtained. With nitrite as electron acceptor a maximum specific oxidation rate of 55 nmol NH4+ min-1 (mg protein)-1 was determined. Although this reaction is 25-fold faster than in Nitrosomonas, it allowed growth at a rate of only 0.003 h-1 (doubling time 11 days). 15N labeling studies showed that hydroxylamine and hydrazine were important intermediates in this new process. A novel type of hydroxylamine oxidoreductase containing an unusual P468 cytochrome has been purified from the Anammox culture. Microsensor studies have shown that at the oxic/anoxic interface of many ecosystems nitrite and ammonia occur in the absence of oxygen. In addition, the number of reports on unaccounted high nitrogen losses in wastewater treatment is gradually increasing, indicating that anaerobic ammonium oxidation may be more widespread than previously assumed. The recently developed nitrification systems in which oxidation of nitrite to nitrate is prevented form an ideal partner for the Anammox process. The combination of these partial nitrification and Anammox processes remains a challenge for future application in the removal of ammonium from wastewater with high ammonium concentrations.
Topics: Anaerobiosis; Bacteria, Anaerobic; Biodegradation, Environmental; Nitrogen; Oxidation-Reduction; Quaternary Ammonium Compounds; Waste Disposal, Fluid; Water Pollutants, Chemical
PubMed: 9990725
DOI: 10.1111/j.1574-6976.1998.tb00379.x -
Nature Microbiology Apr 2021The herbivore digestive tract is home to a complex community of anaerobic microbes that work together to break down lignocellulose. These microbiota are an untapped...
The herbivore digestive tract is home to a complex community of anaerobic microbes that work together to break down lignocellulose. These microbiota are an untapped resource of strains, pathways and enzymes that could be applied to convert plant waste into sugar substrates for green biotechnology. We carried out more than 400 parallel enrichment experiments from goat faeces to determine how substrate and antibiotic selection influence membership, activity, stability and chemical productivity of herbivore gut communities. We assembled 719 high-quality metagenome-assembled genomes (MAGs) that are unique at the species level. More than 90% of these MAGs are from previously unidentified herbivore gut microorganisms. Microbial consortia dominated by anaerobic fungi outperformed bacterially dominated consortia in terms of both methane production and extent of cellulose degradation, which indicates that fungi have an important role in methane release. Metabolic pathway reconstructions from MAGs of 737 bacteria, archaea and fungi suggest that cross-domain partnerships between fungi and methanogens enabled production of acetate, formate and methane, whereas bacterially dominated consortia mainly produced short-chain fatty acids, including propionate and butyrate. Analyses of carbohydrate-active enzyme domains present in each anaerobic consortium suggest that anaerobic bacteria and fungi employ mostly complementary hydrolytic strategies. The division of labour among herbivore anaerobes to degrade plant biomass could be harnessed for industrial bioprocessing.
Topics: Anaerobiosis; Animals; Anti-Bacterial Agents; Archaea; Bacteria, Anaerobic; Biomass; Cellulose; Feces; Fungi; Gastrointestinal Microbiome; Goats; Lignin; Metabolome; Metagenome; Methane; Microbial Consortia; Phylogeny
PubMed: 33526884
DOI: 10.1038/s41564-020-00861-0