Recent evolution of antibiotic resistance in the anaerobes as compared to previous decades.

PubMed

Boyanova, Lyudmila; Kolarov, Rossen; Mitov, Ivan

2015-02-01

Evolution of antibiotic resistance in the anaerobes was reviewed using recent data covering 2000-2013 as compared to previous years. All studies reported growing moxifloxacin resistance in Bacteroides/Parabacteroides spp. in Europe and USA and in Clostridium difficile in Europe. In half or more studies, the resistance rates in Bacteroides/Parabacteroides spp. to amoxicillin-clavulanate or ampicillin-sulbactam and clindamycin rose. In some studies, an increase in resistance was found in Bacteroides/Parabacteroides spp. to cefoxitin/cefotetan and carbapenems, in Prevotella spp. to penicillins, in anaerobic cocci to clindamycin and in Bacteroides/Parabacteroides spp. and C. difficile to metronidazole. Decreasing resistance was also observed, e.g. in Bacteroides/Parabacteroides spp. to cephalosporins, in Prevotella spp. and C. difficile to tetracyclines and in C. difficile to rifampin. No resistance changes were found to tigecycline, in Bacteroides/Parabacteroides spp. to chloramphenicol and in C. difficile to vancomycin. Factors influencing the resistance were the species, ribotype, country, hospital centre, antibiotic consumption and specimen type. In conclusion, the antibiotic resistance changes in the anaerobes are diverse and dynamic. Regular national surveys of resistance and both anaerobic microbiology and susceptibility testing of the isolates become more and more valuable. Copyright © 2014 Elsevier Ltd. All rights reserved.

Frequency of resistance in obligate anaerobic bacteria isolated from dogs, cats, and horses to antimicrobial agents.

PubMed

Lawhon, S D; Taylor, A; Fajt, V R

2013-11-01

Clinical specimens from dogs, cats, and horses were examined for the presence of obligate anaerobic bacteria. Of 4,018 specimens cultured, 368 yielded 606 isolates of obligate anaerobic bacteria (248 from dogs, 50 from cats, and 308 from horses). There were 100 specimens from 94 animals from which only anaerobes were isolated (25 dogs, 8 cats, and 61 horses). The most common sites tested were abdominal fluid (dogs and cats) and intestinal contents (horses). The most common microorganism isolated from dogs, cats, and horses was Clostridium perfringens (75, 13, and101 isolates, respectively). The MICs of amoxicillin with clavulanate, ampicillin, chloramphenicol, metronidazole, and penicillin were determined using a gradient endpoint method for anaerobes. Isolates collected at necropsy were not tested for antimicrobial susceptibility unless so requested by the clinician. There were 1/145 isolates tested that were resistant to amoxicillin-clavulanate (resistance breakpoint ≥ 16/8 μg/ml), 7/77 isolates tested were resistant to ampicillin (resistance breakpoint ≥ 2 μg/ml), 4/242 isolates tested were resistant to chloramphenicol (resistance breakpoint ≥ 32 μg/ml), 12/158 isolates tested were resistant to clindamycin (resistance breakpoint ≥ 8 μg/ml), 10/247 isolates tested were resistant to metronidazole (resistance breakpoint ≥ 32 μg/ml), and 54/243 isolates tested were resistant to penicillin (resistance breakpoint ≥ 2 μg/ml). These data suggest that anaerobes are generally susceptible to antimicrobial drugs in vitro.

Antimicrobial resistance and prevalence of resistance genes of obligate anaerobes isolated from periodontal abscesses.

PubMed

Xie, Yi; Chen, Jiazhen; He, Junlin; Miao, Xinyu; Xu, Meng; Wu, Xingwen; Xu, Beiyun; Yu, Liying; Zhang, Wenhong

2014-02-01

This study attempts to determine the antimicrobial resistance profiles of obligate anaerobic bacteria that were isolated from a periodontal abscess and to evaluate the prevalence of resistance genes in these bacteria. Forty-one periodontal abscess samples were cultivated on selective and non-selective culture media to isolate the oral anaerobes. Their antibiotic susceptibilities to clindamycin, doxycycline, amoxicillin, imipenem, cefradine, cefixime, roxithromycin, and metronidazole were determined using the agar dilution method, and polymerase chain reaction assays were performed to detect the presence of the ermF, tetQ, nim, and cfxA drug resistance genes. A total of 60 different bacterial colonies was isolated and identified. All of the isolates were sensitive to imipenem. Of the strains, 6.7%, 13.3%, 16.7%, and 25% were resistant to doxycycline, metronidazole, cefixime, and amoxicillin, respectively. The resistance rate for both clindamycin and roxithromycin was 31.7%. Approximately 60.7% of the strains had the ermF gene, and 53.3% of the amoxicillin-resistant strains were found to have the cfxA gene. Two nim genes that were found in eight metronidazole-resistant strains were identified as nimB. In the present study, the Prevotella species are the most frequently isolated obligate anaerobes from periodontal abscesses. The current results show their alarmingly high resistance rate against clindamycin and roxithromycin; thus, the use of these antibiotics is unacceptable for the empirical therapy of periodontal abscesses. A brief prevalence of four resistance genes in the anaerobic bacteria that were isolated was also demonstrated.

The Genome Sequence of the Obligately Chemolithoautotrophic, Facultatively Anaerobic Bacterium Thiobacillus denitrificans

PubMed Central

Beller, Harry R.; Chain, Patrick S. G.; Letain, Tracy E.; Chakicherla, Anu; Larimer, Frank W.; Richardson, Paul M.; Coleman, Matthew A.; Wood, Ann P.; Kelly, Donovan P.

2006-01-01

The complete genome sequence of Thiobacillus denitrificans ATCC 25259 is the first to become available for an obligately chemolithoautotrophic, sulfur-compound-oxidizing, β-proteobacterium. Analysis of the 2,909,809-bp genome will facilitate our molecular and biochemical understanding of the unusual metabolic repertoire of this bacterium, including its ability to couple denitrification to sulfur-compound oxidation, to catalyze anaerobic, nitrate-dependent oxidation of Fe(II) and U(IV), and to oxidize mineral electron donors. Notable genomic features include (i) genes encoding c-type cytochromes totaling 1 to 2 percent of the genome, which is a proportion greater than for almost all bacterial and archaeal species sequenced to date, (ii) genes encoding two [NiFe]hydrogenases, which is particularly significant because no information on hydrogenases has previously been reported for T. denitrificans and hydrogen oxidation appears to be critical for anaerobic U(IV) oxidation by this species, (iii) a diverse complement of more than 50 genes associated with sulfur-compound oxidation (including sox genes, dsr genes, and genes associated with the AMP-dependent oxidation of sulfite to sulfate), some of which occur in multiple (up to eight) copies, (iv) a relatively large number of genes associated with inorganic ion transport and heavy metal resistance, and (v) a paucity of genes encoding organic-compound transporters, commensurate with obligate chemolithoautotrophy. Ultimately, the genome sequence of T. denitrificans will enable elucidation of the mechanisms of aerobic and anaerobic sulfur-compound oxidation by β-proteobacteria and will help reveal the molecular basis of this organism's role in major biogeochemical cycles (i.e., those involving sulfur, nitrogen, and carbon) and groundwater restoration. PMID:16452431

Simultaneous isolation of anaerobic bacteria from udder abscesses and mastitic milk in lactating dairy cows.

PubMed

Greeff, A S; du Preez, J H

1985-12-01

A variety of non-sporulating anaerobic bacterial species were isolated from udder abscesses in 10 lactating dairy cows. Fifty percent of the abscesses yielded multiple anaerobic species and the other 50% only 1 species. The anaerobic bacteria, however, were always accompanied by classical facultative anaerobic mastitogenic bacteria. In four of the five cows also afflicted with mastitis in the quarters with abscesses, the anaerobic and facultative anaerobic bacteria were identical. Peptococcus indolicus was the most commonly isolated organism followed by Eubacterium and Bacteroides spp. Bacteroides fragilis was resistant to penicillin, ampicillin and tetracycline.

Occurrence and molecular characterization of cultivable mesophilic and thermophilic obligate anaerobic bacteria isolated from paper mills.

PubMed

Suihko, Maija-Liisa; Partanen, Laila; Mattila-Sandholm, Tiina; Raaska, Laura

2005-08-01

The aim of this work was to characterize the cultivable obligate anaerobic bacterial population in paper mill environments. A total of 177 anaerobically grown bacterial isolates were screened for aerotolerance, from which 67 obligate anaerobes were characterized by automated ribotyping and 41 were further identified by partial 16S rDNA sequencing. The mesophilic isolates indicated 11 different taxa (species) within the genus Clostridium and the thermophilic isolates four taxa within the genus Thermoanaerobacterium and one within Thermoanaerobacter (both formerly Clostridium). The most widespread mesophilic bacterium was closely related to C. magnum and occurred in three of four mills. One mill was contaminated with a novel mesophilic bacterium most closely related to C. thiosulfatireducens. The most common thermophile was T. thermosaccharolyticum, occurring in all four mills. The genetic relationships of the mill isolates to described species indicated that most of them are potential members of new species. On the basis of identical ribotypes clay could be identified to be the contamination source of thermophilic bacteria. Automated ribotyping can be a useful tool for the identification of clostridia as soon as comprehensive identification libraries are available.

Growth yields and fermentation balance of Bacteroides fragilis cultured in glucose-enriched medium.

PubMed

Frantz, J C; McCallum, R E

1979-03-01

Bacteroides fragilis is an obligate anaerobic bacterium classified with the gram-negative, non-sporeforming bacilli and is the Bacteroides species most frequently isolated from human infections. In the present study, experiments were designed to investigate growth characteristics of B. fragilis in a complex medium. In a minimal defined medium, which was employed for comparison purposes, B. fragilis grew with a generation time of 2 h. Growth of the organism in glucose-enriched medium used in the present study was superior. Maximum generation time was 60 min. Total and viable cells (colony-forming units) were 8.9 x 10(9) and 2.1 x 10(9), respectively, at maximum measurable growth. The molar growth yield (Ym) was 51.5. Growth yields were found to reach a maximum 2 to 3 h before maximum growth and to vary with respect to the phase of growth. Estimates of the fermentation products indicated that glucose was the sole energy substrate. Major products included acetic acid, propionic acid, lactic acid, and succinic acid. Other products included ethyl alcohol, pyruvic acid, and fumaric acid. No attempt was made to recover CO2 or formic acid. The OR balances from two experiments were 0.013 and -0.093 and the respective carbon recoveries were 6.268 and 6.241. The results of the present study show that B. fragilis is capable of rapid rates of growth in vitro by using glucose as the sole energy source.

Complete genome sequence of Bacteroides salanitronis type strain (BL78T)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gronow, Sabine; Held, Brittany; Lucas, Susan

2011-01-01

Bacteroides salanitronis Lan et al. 2006 is a species of the genus Bacteroides, which belongs to the family Bacteroidaceae. The species is of interest because it was isolated from the gut of a chicken and the growing awareness that the anaerobic microflora of the cecum is of benefit for the host and may impact poultry farming. The 4,308,663 bp long genome consists of a 4.24 Mbp chromosome and three plasmids (6 kbp, 19 kbp, 40 kbp) containing 3,737 protein-coding and 101 RNA genes and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

Anaerobic bacteraemia revisited: species and susceptibilities.

PubMed

Ng, Lily S Y; Kwang, Lee Ling; Rao, Suma; Tan, Thean Yen

2015-01-01

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. 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. 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. 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

Lipogenesis and Redox Balance in Nitrogen-Fixing Pea Bacteroids.

PubMed

Terpolilli, Jason J; Masakapalli, Shyam K; Karunakaran, Ramakrishnan; Webb, Isabel U C; Green, Rob; Watmough, Nicholas J; Kruger, Nicholas J; Ratcliffe, R George; Poole, Philip S

2016-10-15

Within legume root nodules, rhizobia differentiate into bacteroids that oxidize host-derived dicarboxylic acids, which is assumed to occur via the tricarboxylic acid (TCA) cycle to generate NAD(P)H for reduction of N2 Metabolic flux analysis of laboratory-grown Rhizobium leguminosarum showed that the flux from [(13)C]succinate was consistent with respiration of an obligate aerobe growing on a TCA cycle intermediate as the sole carbon source. However, the instability of fragile pea bacteroids prevented their steady-state labeling under N2-fixing conditions. Therefore, comparative metabolomic profiling was used to compare free-living R. leguminosarum with pea bacteroids. While the TCA cycle was shown to be essential for maximal rates of N2 fixation, levels of pyruvate (5.5-fold reduced), acetyl coenzyme A (acetyl-CoA; 50-fold reduced), free coenzyme A (33-fold reduced), and citrate (4.5-fold reduced) were much lower in bacteroids. Instead of completely oxidizing acetyl-CoA, pea bacteroids channel it into both lipid and the lipid-like polymer poly-β-hydroxybutyrate (PHB), the latter via a type III PHB synthase that is active only in bacteroids. Lipogenesis may be a fundamental requirement of the redox poise of electron donation to N2 in all legume nodules. Direct reduction by NAD(P)H of the likely electron donors for nitrogenase, such as ferredoxin, is inconsistent with their redox potentials. Instead, bacteroids must balance the production of NAD(P)H from oxidation of acetyl-CoA in the TCA cycle with its storage in PHB and lipids. Biological nitrogen fixation by symbiotic bacteria (rhizobia) in legume root nodules is an energy-expensive process. Within legume root nodules, rhizobia differentiate into bacteroids that oxidize host-derived dicarboxylic acids, which is assumed to occur via the TCA cycle to generate NAD(P)H for reduction of N2 However, direct reduction of the likely electron donors for nitrogenase, such as ferredoxin, is inconsistent with their redox

Lipogenesis and Redox Balance in Nitrogen-Fixing Pea Bacteroids

PubMed Central

Terpolilli, Jason J.; Masakapalli, Shyam K.; Karunakaran, Ramakrishnan; Webb, Isabel U. C.; Green, Rob; Watmough, Nicholas J.; Kruger, Nicholas J.; Ratcliffe, R. George

2016-01-01

ABSTRACT Within legume root nodules, rhizobia differentiate into bacteroids that oxidize host-derived dicarboxylic acids, which is assumed to occur via the tricarboxylic acid (TCA) cycle to generate NAD(P)H for reduction of N2. Metabolic flux analysis of laboratory-grown Rhizobium leguminosarum showed that the flux from [13C]succinate was consistent with respiration of an obligate aerobe growing on a TCA cycle intermediate as the sole carbon source. However, the instability of fragile pea bacteroids prevented their steady-state labeling under N2-fixing conditions. Therefore, comparative metabolomic profiling was used to compare free-living R. leguminosarum with pea bacteroids. While the TCA cycle was shown to be essential for maximal rates of N2 fixation, levels of pyruvate (5.5-fold reduced), acetyl coenzyme A (acetyl-CoA; 50-fold reduced), free coenzyme A (33-fold reduced), and citrate (4.5-fold reduced) were much lower in bacteroids. Instead of completely oxidizing acetyl-CoA, pea bacteroids channel it into both lipid and the lipid-like polymer poly-β-hydroxybutyrate (PHB), the latter via a type III PHB synthase that is active only in bacteroids. Lipogenesis may be a fundamental requirement of the redox poise of electron donation to N2 in all legume nodules. Direct reduction by NAD(P)H of the likely electron donors for nitrogenase, such as ferredoxin, is inconsistent with their redox potentials. Instead, bacteroids must balance the production of NAD(P)H from oxidation of acetyl-CoA in the TCA cycle with its storage in PHB and lipids. IMPORTANCE Biological nitrogen fixation by symbiotic bacteria (rhizobia) in legume root nodules is an energy-expensive process. Within legume root nodules, rhizobia differentiate into bacteroids that oxidize host-derived dicarboxylic acids, which is assumed to occur via the TCA cycle to generate NAD(P)H for reduction of N2. However, direct reduction of the likely electron donors for nitrogenase, such as ferredoxin, is inconsistent

Porphyromonas (Bacteroides) endodontalis: its role in endodontal infections.

PubMed

van Winkelhoff, A J; van Steenbergen, T J; de Graaff, J

1992-09-01

Porphyromonas endodontalis (formerly Bacteroides endodontalis) is a black-pigmented anaerobic Gram-negative rod which is associated with endodontal infections. It has been isolated from infected dental root canals and submucous abscesses of endodontal origin. The presence of P. endodontalis in infected dental root canals has been correlated with symptoms of an acute infection. It is occasionally found on oral mucous membranes and periodontal pockets. P. endodontalis has shown relatively low virulence in experimental monoinfections. In anaerobic mixed infections it can play an essential role. Differences in virulence between strains have been related to capsular material. On the basis of different types of capsules, three serotypes have been described. P. endodontalis is sensitive to a wide range of antibiotics, including the penicillins, the tetracyclines, and metronidazole.

Near-complete genome sequence of the cellulolytic Bacterium Bacteroides ( Pseudobacteroides) cellulosolvens ATCC 35603

DOE PAGES

Dassa, Bareket; Utturkar, Sagar M.; Hurt, Richard A.; ...

2015-09-24

We report the single-contig genome sequence of the anaerobic, mesophilic, cellulolytic bacterium, Bacteroides cellulosolvens. The bacterium produces a particularly elaborate cellulosome system, whereas the types of cohesin-dockerin interactions are opposite of other known cellulosome systems: cell-surface attachment is thus mediated via type-I interactions whereas enzymes are integrated via type-II interactions.

Vertebral osteomyelitis caused by Prevotella (Bacteroides) melaninogenicus.

PubMed

Mukhopadhyay, Surabhi; Rose, Fredrick; Frechette, Vincent

2005-02-01

A 35-year-old, previously healthy female presented with severe low back pain, fever, and a high erythrocyte sedimentation rate 1 week after a routine dental cleaning. Technetium-labeled leukocyte scanning and magnetic resonance imaging scan of the spine were negative for osteomyelitis. The patient underwent biopsy, cultures from which grew Prevotella (Bacteroides) melaninogenicus. Appropriate antibiotic therapy resulted in resolution of symptoms. P. melaninogenicus is a gram-negative anaerobic bacillus that is part of the indigenous oral flora. It may cause dental, sinus, skin, and soft tissue infections. Infection of bone is rare. Only three cases of vertebral osteomyelitis due to P. melaninogenicus have been reported in the literature. The early diagnosis of vertebral osteomyelitis requires a high index of clinical suspicion and cannot be excluded by negative imaging tests alone. The recovery of this unusual organism highlights the importance of requesting anaerobic cultures of biopsy specimens.

Characterization of saccharolytic Bacteroides and Prevotella isolates from infected dog and cat bite wounds in humans.

PubMed Central

Alexander, C J; Citron, D M; Hunt Gerardo, S; Claros, M C; Talan, D; Goldstein, E J

1997-01-01

Saccharolytic, nonpigmented, anaerobic gram-negative rods isolated from infected dog and cat bite wounds in humans have been poorly characterized, and most are not included in the databases of kits used for anaerobic identification; thus, they are problematic for clinical laboratories to identify. Fifty strains isolated from such wounds were characterized with commercial kits for preformed-enzyme detection, carbohydrate fermentation, and other biochemical tests. PCR fingerprinting was performed on these strains to further characterize subgroups within these species. Bacteroides tectum is a frequent isolate in bite wounds and resembles Prevotella bivia in colony morphology and saccharolytic activity, except that it grows in 20% bile and hydrolyzes esculin. Profile numbers generated by various kits associate B. tectum with P. bivia, Prevotella oralis group, or Prevotella melaninogenica. PCR fingerprinting identified at least four subgroups and confirmed the heterogeneous nature of this species. Prevotella heparinolytica was also frequently isolated from these bite wounds. It produces indole and generates a profile number in preformed-enzyme kits that is usually associated with Bacteroides uniformis. However, it is bile sensitive and quite distinct from the Bacteroides fragilis group of anaerobes. The PCR fingerprint profiles generated by strains of P. heparinolytica were very similar to that of the type strain and to each other. Prevotella zoogleoformans, occasionally isolated from dog and cat bite wounds in humans, resembles P. heparinolytica except for a negative indole test. Clinical laboratories should be aware of the characteristics of these animal species when identifying isolates from animal bite wounds in humans. PMID:9003606

Characterization of saccharolytic Bacteroides and Prevotella isolates from infected dog and cat bite wounds in humans.

PubMed

Alexander, C J; Citron, D M; Hunt Gerardo, S; Claros, M C; Talan, D; Goldstein, E J

1997-02-01

Saccharolytic, nonpigmented, anaerobic gram-negative rods isolated from infected dog and cat bite wounds in humans have been poorly characterized, and most are not included in the databases of kits used for anaerobic identification; thus, they are problematic for clinical laboratories to identify. Fifty strains isolated from such wounds were characterized with commercial kits for preformed-enzyme detection, carbohydrate fermentation, and other biochemical tests. PCR fingerprinting was performed on these strains to further characterize subgroups within these species. Bacteroides tectum is a frequent isolate in bite wounds and resembles Prevotella bivia in colony morphology and saccharolytic activity, except that it grows in 20% bile and hydrolyzes esculin. Profile numbers generated by various kits associate B. tectum with P. bivia, Prevotella oralis group, or Prevotella melaninogenica. PCR fingerprinting identified at least four subgroups and confirmed the heterogeneous nature of this species. Prevotella heparinolytica was also frequently isolated from these bite wounds. It produces indole and generates a profile number in preformed-enzyme kits that is usually associated with Bacteroides uniformis. However, it is bile sensitive and quite distinct from the Bacteroides fragilis group of anaerobes. The PCR fingerprint profiles generated by strains of P. heparinolytica were very similar to that of the type strain and to each other. Prevotella zoogleoformans, occasionally isolated from dog and cat bite wounds in humans, resembles P. heparinolytica except for a negative indole test. Clinical laboratories should be aware of the characteristics of these animal species when identifying isolates from animal bite wounds in humans.

Pirin-like proteins are regulated by oxidative stress and iron in bacteroides fragilis and involved in the modulation of central energy metabolism and metronidazole susceptibility

USDA-ARS?s Scientific Manuscript database

Bacteroides fragilis is the most frequent anaerobe isolated from human infections. Clinical isolates of B. fragilis are among the highest aerotolerant anaerobic bacteria. The oxidative stress response (OSR) in B. fragilis induces an array of genes enabling them to survive prolonged oxygen exposure i...

The role of black-pigmented Bacteroides in human oral infections.

PubMed

van Winkelhoff, A J; van Steenbergen, T J; de Graaff, J

1988-03-01

Today, 10 black-pigmented Bacteroides (BPB) species are recognized. The majority of these species can be isolated from the oral cavity. BPB species are involved in anaerobic infections of oral and non-oral sites. In the oral cavity, BPB species are associated with gingivitis, periodontitis, endodontal infections and odontogenic abscesses. Cultural studies suggest a specific role of the various BPB species in the different types of infection. Bacteroides gingivalis is closely correlated with destructive periodontitis in adults as well as in juveniles. Bacteroides intermedius seems to be less specific since it is found in gingivitis, periodontitis, endodontal infections and odontogenic abscesses. The recently described Bacteroides endodontalis is closely associated with endodontal infections and odontogenic abscesses of endodontal origin. There are indications that these periodontopathic BPB species are only present in the oral cavity of subjects suffering from periodontal breakdown, being absent on the mucosal surfaces of subjects without periodontal breakdown. BPB species associated with healthy oral conditions are Bacteroides melaninogenicus, Bacteroides denticola and Bacteroides loescheii. There are indications that these BPB species are part of the normal indigenous oral microflora. Many studies in the past have documented the pathogenic potential and virulence of BPB species. This virulence can be explained by the large numbers of virulence factors demonstrated in this group of micro-organisms. Among others, the proteolytic activity seems to be one of the most important features. Several artificial substrates as well as numerous biological proteins are degraded. These include anti-inflammatory proteins such as alpha-2-macroglobulin, alpha-1-antitrypsin, C3 and C5 complement factors and immunoglobulins. B. gingivalis is by far the most proteolytic species, followed by B. endodontalis. Like other bacteria, the lipopolysaccharide of B. gingivalis has shown to be

Bacteroides cellulosilyticus sp. nov., a cellulolytic bacterium from the human gut microbial community.

PubMed

Robert, Céline; Chassard, Christophe; Lawson, Paul A; Bernalier-Donadille, Annick

2007-07-01

A strictly anaerobic cellulolytic bacterium, strain CRE21(T), was isolated from a human faecal sample. Cells were Gram-negative non-motile rods that were about 1.7 microm in length and 0.9 microm in width. Strain CRE21(T) degraded different types of cellulose and was able to grow on a variety of carbohydrates. Cellulose and sugars were mainly converted to acetate, propionate and succinate. The G+C content of the DNA was 41.1 mol%. 16S rRNA gene sequence analysis revealed that the isolate belonged to the genus Bacteroides with highest sequence similarity to the type strain of Bacteroides intestinalis (98 %). DNA-DNA hybridization results revealed that strain CRE21(T) was distinct from B. intestinalis (40 % DNA-DNA relatedness). Strain CRE21(T) also showed several characteristics distinct from B. intestinalis. In particular, it exhibited different capacity to degrade polysaccharides such as cellulose. On the basis of phylogenetic analysis and the morphological, physiological and biochemical data presented in this study, strain CRE21(T) can be readily differentiated from recognized species of the genus Bacteroides. The name Bacteroides cellulosilyticus sp. nov. is proposed to accommodate this organism. The type strain is CRE21(T) (=DSM 14838(T)=CCUG 44979(T)).

The Bacteroides fragilis cell envelope: quarterback, linebacker, coach-or all three?

PubMed

Pumbwe, Lilian; Skilbeck, Christopher A; Wexler, Hannah M

2006-01-01

Bacteroides fragilis is an anaerobic commensal constituting only 1-2% of the micro-flora of the human gastrointestinal tract, yet it is the predominant anaerobic isolate in cases of intraabdominal sepsis and bacteremia. B. fragilis can play two roles in the host: in its role as friendly commensal, it must be able to establish itself in the host intestinal mucosa, to utilize and process polysaccharides for use by the host, and to resist the noxious effects of bile salts. In its role as pathogen, it must be able to attach itself to the site of infection, evade killing mechanisms by host defense, withstand antimicrobial treatment and produce factors that damage host tissue. The cell envelope of B. fragilis, likewise, must be able to function in the roles of aggressor, defender and strategist in allowing the organism to establish itself in the host--whether as friend or foe. Recent studies of the genomes and proteomes of the genus Bacteroides suggest that these organisms have evolved strategies to survive and dominate in the overcrowded gastrointestinal neighborhood. Analysis of the proteomes of B. fragilis and Bacteroides thetaiotaomicron demonstrates both a tremendous capacity to use a wide range of dietary polysaccharides, and the capacity to create variable surface antigenicities by multiple DNA inversion systems. The latter characteristic is particularly pronounced in the species B. fragilis, which is more frequently found at the mucosal surface (i.e., often the site of attack by host defenses). The B. fragilis cell envelope undergoes major protein expression and ultrastructural changes in response to stressors such as bile or antimicrobial agents. These agents may also act as signals for attachment and colonization. Thus the bacterium manages its surface characteristics to enable it to bind to its target, to use the available nutrients, and to avoid or evade hostile forces (host-derived or external) in its multiple roles.

Image analyzing method to evaluate in situ bioluminescence from an obligate anaerobe cultivated under various dissolved oxygen concentrations.

PubMed

Ninomiya, Kazuaki; Yamada, Ryuji; Matsumoto, Masami; Fukiya, Satoru; Katayama, Takane; Ogino, Chiaki; Shimizu, Nobuaki

2013-02-01

An image analyzing method was developed to evaluate in situ bioluminescence expression, without exposing the culture sample to the ambient oxygen atmosphere. Using this method, we investigated the effect of dissolved oxygen concentration on bioluminescence from an obligate anaerobe Bifidobacterium longum expressing bacterial luciferase which catalyzes an oxygen-requiring bioluminescent reaction. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Bacteroides endodontalis and other black-pigmented Bacteroides species in odontogenic abscesses.

PubMed Central

van Winkelhoff, A J; Carlee, A W; de Graaff, J

1985-01-01

Twenty-eight odontogenic abscesses were examined for the presence of black-pigmented Bacteroides spp. Of the 28 samples, 26 were found to contain one or more species of black-pigmented Bacteroides. Abscesses were divided into three categories according to the tissue of origin: endodontal, periodontal, and pericoronal. Four abscesses which developed after extraction were also examined. It was found that Bacteroides endodontalis, a newly described species of asaccharolytic black-pigmented Bacteroides, was isolated almost exclusively from periapical abscesses of endodontal origin. B. intermedius proved to be the most frequently isolated species in all of the samples. B. gingivalis was present in all of the periodontal abscesses studied, as well as in two endodontal abscesses. B. melaninogenicus was recovered once from a pericoronal abscess. Precautions for the isolation of B. endodontalis are discussed. PMID:4030089

Marsh soils as potential sinks for Bacteroides fecal indicator bacteria, Waccamaw National Wildlife Refuge, Georgetown, SC, USA

USGS Publications Warehouse

Drexler, Judith Z.; Johnson, Heather E.; Duris, Joseph W.; Krauss, Ken W.

2014-01-01

A soil core collected in a tidal freshwater marsh in the Waccamaw National Wildlife Refuge (Georgetown, SC) exuded a particularly strong odor of cow manure upon extrusion. In order to test for manure and determine its provenance, we carried out microbial source tracking using DNA markers for Bacteroides, a noncoliform, anaerobic bacterial group that represents a broad group of the fecal population. Three core sections from 0-3 cm, 9-12 cm and 30-33 were analyzed for the presence of Bacteroides. The ages of core sediments were estimated using 210Pb and 137Cs dating. All three core sections tested positive for Bacteroides DNA markers related to cow or deer feces. Because cow manure is stockpiled, used as fertilizer, and a source of direct contamination in the Great Pee Dee River/Winyah Bay watershed, it is very likely the source of the Bacteroides that was deposited on the marsh. The mid-points of the core sections were dated as follows: 0-3 cm: 2009; 9-12 cm: 1999, and 30-33 cm: 1961. The presence of Bacteroides at different depths/ages in the soil profile indicates that soils in tidal freshwater marshes are, at the least, capable of being short-term sinks for Bacteroides and, may have the potential to be long-term sinks of stable, naturalized populations.

Bacterial infection of the lower respiratory tract in 34 horses.

PubMed

Racklyeft, D J; Love, D N

2000-08-01

To investigate associations between the bacteriology and aspects of history, clinical presentation, outcome and pathology of lower respiratory tract disease of 34 horses. Detailed aerobic and anaerobic bacteriological investigations were performed on clinical specimens from horses with pneumonia, lung abscessation and necrotic pneumonia with or without pleurisy in an attempt to identify those bacteria that might contribute to the initiation and progression of infection. Bacteria were cultured from 33 of the 34 horses. In ten cases, only aerobic/facultatively anaerobic isolates were cultured while aerobic/facultatively anaerobic bacteria and obligately anaerobic bacteria were isolated in the other 23 cases. Moderate to large numbers of anaerobic bacteria were isolated only when the estimated duration of illness was at least five days. Bacteria were not cultured from 12 of the pleural fluid samples but were always cultured from pulmonary samples (either transtracheal aspirates from live horses or pulmonary lesions at necropsy). Streptococcus equi subsp zooepidemicus was isolated in the three cases where only one bacterial species was cultured. In the other 30 cases, multiple species were isolated. These included most often and in greatest numbers, Streptococcus equi subsp zooepidemicus, Pasteurellaceae, Escherichia coli, anaerobic cocci, Eubacterium fossor, Bacteroides tectum, Prevotella heparinolytica, Fusobacterium spp, and pigmented members of the genera Prevotella and Porphyromonas. Aerobic/facultatively anaerobic organisms were isolated from 97% of horses, while obligately anaerobic organisms were cultured from 68% of horses. There was no association between the isolation of any specific bacterium and the outcome of disease. However, obligately anaerobic bacteria (such as anaerobic cocci, Bacteroides tectum, P heparinolytica and Fusobacterium spp) and the facultatively anaerobic species Escherichia coli, were recovered more commonly from horses that died or were

Microbiology and management of joint and bone infections due to anaerobic bacteria.

PubMed

Brook, Itzhak

2008-03-01

To describes the microbiology, diagnosis, and management of septic arthritis and osteomyelitis due to anaerobic bacteria. The predominant anaerobes in arthritis are anaerobic Gram-negative bacilli (AGNB) including the Bacteroides fragilis group, Fusobacterium spp., Peptostreptococcus spp., and Propionibacterium acnes. Infection with P. acnes is associated with a prosthetic joint, previous surgery, and trauma. B. fragilis group is associated with distant infection, Clostridium spp. with trauma, and Fusobacterium spp. with oropharyngeal infection. Most cases of anaerobic arthritis, in contrast to anaerobic osteomyelitis, involved a single isolate, and most cases are secondary to hematogenous spread. The predominant anaerobes in osteomyelitis are Bacteroides, Peptostreptococcus, Fusobacterium, and Clostridium spp. as well as P. acnes. Conditions predisposing to bone infections are vascular disease, bites, contiguous infection, peripheral neuropathy, hematogenous spread, and trauma. Pigmented Prevotella and Porphyromonas spp. are mostly isolated in skull and bite infections, members of the B. fragilis group in hand and feet infections, and Fusobacterium spp. in skull, bite, and hematogenous long bone infections. Many patients with osteomyelitis due to anaerobic bacteria have evidence of an anaerobic infection elsewhere in the body that is the source of the organisms involved in the osteomyelitis. Treatment of arthritis and osteomyelitis involving anaerobic bacteria includes symptomatic therapy, immobilization in some cases, adequate drainage of purulent material, and antibiotic therapy effective against these organisms. Anaerobic bacteria can cause septic arthritis and osteomyelitis. Correct diagnosis and appropriate therapy are important contributor to successful outcome.

High quality draft genome sequence of Bacteroides barnesiae type strain BL2T (DSM 18169T) from chicken caecum

DOE PAGES

Sakamoto, Mitsuo; Lapidus, Alla L.; Han, James; ...

2015-08-02

Bacteroides barnesiae Lan et al. 2006 is a species of the genus Bacteroides, which belongs to the family Bacteroidaceae. Strain BL2T is of interest because it was isolated from the gut of a chicken and the growing awareness that the anaerobic microbiota of the caecum is of benefit for the host and may impact poultry farming. We report that the 3,621,509 bp long genome with its 3,059 protein-coding and 97 RNA genes is a part of the Genomic Encyclopedia of Type Strains, Phase I: the one thousand microbial genomes (KMG) project.

High quality draft genome sequence of Bacteroides barnesiae type strain BL2T (DSM 18169T) from chicken caecum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakamoto, Mitsuo; Lapidus, Alla L.; Han, James

Bacteroides barnesiae Lan et al. 2006 is a species of the genus Bacteroides, which belongs to the family Bacteroidaceae. Strain BL2T is of interest because it was isolated from the gut of a chicken and the growing awareness that the anaerobic microbiota of the caecum is of benefit for the host and may impact poultry farming. We report that the 3,621,509 bp long genome with its 3,059 protein-coding and 97 RNA genes is a part of the Genomic Encyclopedia of Type Strains, Phase I: the one thousand microbial genomes (KMG) project.

The Fumarate Reductase of Bacteroides thetaiotaomicron, unlike That of Escherichia coli, Is Configured so that It Does Not Generate Reactive Oxygen Species.

PubMed

Lu, Zheng; Imlay, James A

2017-01-03

The impact of oxidative stress upon organismal fitness is most apparent in the phenomenon of obligate anaerobiosis. The root cause may be multifaceted, but the intracellular generation of reactive oxygen species (ROS) likely plays a key role. ROS are formed when redox enzymes accidentally transfer electrons to oxygen rather than to their physiological substrates. In this study, we confirm that the predominant intestinal anaerobe Bacteroides thetaiotaomicron generates intracellular ROS at a very high rate when it is aerated. Fumarate reductase (Frd) is a prominent enzyme in the anaerobic metabolism of many bacteria, including B. thetaiotaomicron, and prior studies of Escherichia coli Frd showed that the enzyme is unusually prone to ROS generation. Surprisingly, in this study biochemical analysis demonstrated that the B. thetaiotaomicron Frd does not react with oxygen at all: neither superoxide nor hydrogen peroxide is formed. Subunit-swapping experiments indicated that this difference does not derive from the flavoprotein subunit at which ROS normally arise. Experiments with the related enzyme succinate dehydrogenase discouraged the hypothesis that heme moieties are responsible. Thus, resistance to oxidation may reflect a shift of electron density away from the flavin moiety toward the iron-sulfur clusters. This study shows that the autoxidizability of a redox enzyme can be suppressed by subtle modifications that do not compromise its physiological function. One implication is that selective pressures might enhance the oxygen tolerance of an organism by manipulating the electronic properties of its redox enzymes so they do not generate ROS. Whether in sediments or pathogenic biofilms, the structures of microbial communities are configured around the sensitivities of their members to oxygen. Oxygen triggers the intracellular formation of reactive oxygen species (ROS), and the sensitivity of a microbe to oxygen likely depends upon the rates at which ROS are formed

5-Nitroimidazole-derived Schiff bases and their copper(II) complexes exhibit potent antimicrobial activity against pathogenic anaerobic bacteria.

PubMed

Oliveira, Alexandre A; Oliveira, Ana P A; Franco, Lucas L; Ferencs, Micael O; Ferreira, João F G; Bachi, Sofia M P S; Speziali, Nivaldo L; Farias, Luiz M; Magalhães, Paula P; Beraldo, Heloisa

2018-05-07

In the present work a family of novel secnidazole-derived Schiff base compounds and their copper(II) complexes were synthesized. The antimicrobial activities of the compounds were evaluated against clinically important anaerobic bacterial strains. The compounds exhibited in vitro antibacterial activity against Bacteroides fragilis, Bacteroides thetaiotaomicron, Bacteroides vulgatus, Bacteroides ovatus, Parabacteroides distasonis and Fusubacterium nucleatum pathogenic anaerobic bacteria. Upon coordination to copper(II) the antibacterial activity significantly increased in several cases. Some derivatives were even more active than the antimicrobial drugs secnidazole and metronidazole. Therefore, the compounds under study are suitable for in vivo evaluation and the microorganisms should be classified as susceptible to them. Electrochemical studies on the reduction of the nitro group revealed that the compounds show comparable reduction potentials, which are in the same range of the bio-reducible drugs secnidazole and benznidazole. The nitro group reduction potential is more favorable for the copper(II) complexes than for the starting ligands. Hence, the antimicrobial activities of the compounds under study might in part be related to intracellular bio-reduction activation. Considering the increasing resistance rates of anaerobic bacteria against a wide range of antimicrobial drugs, the present work constitutes an important contribution to the development of new antibacterial drug candidates.

In vitro activity of flomoxef compared to moxalactam, cefoxitin, cefotaxime, and clindamycin against anaerobes.

PubMed

Werner, H; Heizmann, W; Luft, G

1988-11-01

To assess the in vitro activity of flomoxef (6315-S), moxalactam, cefoxitin, cefotaxime, and clindamycin against anaerobes 197 clinical isolates (27 Bacteroides fragilis, 42 B. thetaiotaomicron, 10 B. vulgatus, 7 B. ovatus, 6 B. uniformis, 6 B. distasonis, 7 Bacteroides melaninogenicus group, 11 Bacteroides oralis group, 21 Clostridium difficile, 7 C. perfringens, 3 C. sporogenes, 3 Clostridium spp., 33 Propionibacterium acnes, 14 Peptococcaceae) were studied by means of agar dilution tests. The MIC90 of B. fragilis was less than 2 micrograms/ml for flomoxef, less than 4 micrograms/ml for moxalactam, less than 16 micrograms/ml for cefoxitin, less than 128 micrograms/ml for cefotaxime and less than 2 micrograms/ml for clindamycin. The respective MIC90's of B. thetaiotaomicron were less than 64, less than 128, less than 32, less than 256 and 8 micrograms/ml. Strains of the other Bacteroides species and groups were more susceptible to flomoxef and the other antibiotics than B. thetaiotaomicron. Against Clostridium difficile flomoxef (MIC90 less than 4 micrograms/ml) proved to be superior to the other agents tested. Most of the Clostridium strains other than C. difficile were also susceptible to flomoxef; anaerobic grampositive cocci and Propionibacterium acnes were very sensitive (MIC90's less than 1 and less than or equal to 0.125 micrograms/ml, respectively). Its anti-anaerobic activity, together with its efficacy against aerobes, should make flomoxef a useful adjunct to the arsenal of modern antibiotic therapy.

[Isolation and characterization of Thermopirellula anaerolimosa gen. nov., sp. nov., an obligate anaerobic hydrogen-producing bacterium of the phylum Planctomycetes].

PubMed

Liu, Dongying; Liu, Yi; Men, Xuehui; Guo, Qunqun; Guo, Rongbo; Qiu, Yanling

2012-08-04

To cultivate various yet-to-be cultured heterotrophs from anaerobic granule sludge, we used a selective culture medium with low concentrations of substrates supplemented a variety of antibiotics. An obligate anaerobic, thermophilic, hydrogen-producing bacterium, strain VM20-7(T), was isolated from an upflow anaerobic sludge blanket (UASB) reactor treating high-strength organic wastewater from isomerized sugar production processes. Cells of strain VM20-7(T) are non-motile, spherical, pear or teardrop shaped, occurring singly(o)r as aggregates (0.7 - 2.0 microm x 0.7 - 2.0 microm). Spore formation was not observed. Growth temperature ranges from 35 - 50 degrees C (optimum 45 degrees C), pH ranges from 6.0 - 8.3 (optimum 7.0 - 7.5) , NaCl tolerant concentration ranges from 0% - 0.5% (w/v, optimum 0% ). Nitrate, sulfate, thiosulfate, sulfite, elemental sulfur and Fe (III)-NTA were not used as terminal electron acceptors. Strain VM20-7(T) utilizes a wide range of carbohydrates, including glucose, maltose, ribose, xylose, sucrose, galactose, mannose, raffinose, pectin, yeast extract and xylan. Acetate and H2 are the main end products of glucose fermentation. The G + C content of the genomic DNA was 60.9 mol%. 16S rRNA gene sequence analysis revealed that it is related to the Pirellula-Rhodopirellula-Blastopirellula (PRB) clade within the order Planctomycetales (82.7 - 84.3% similarity with 16S rRNA genes of other known related species). The first obligate anaerobic bacterium within the phylum Planctomycetes was isolated with low concentration of carbohydrates and antibiotics. On the basis of the physiological and phylogenetic data, the name Thermopirellula anaerolimosa gen. nov. , sp. nov. is proposed for strain VM20-7(T) (= CGMCC 1.5169(T) = JCM 17478(T) = DSM 24165(T)).

In Vitro Activity of Penicillins Against Anaerobes

PubMed Central

Tally, Francis P.; Jacobus, Nilda V.; Bartlett, John G.; Gorbach, Sherwood L.

1975-01-01

The in vitro susceptibility of 162 anaerobic isolates from clinical material were tested to pencillin G, BL-P1654, and carbenicillin. Penicillin G and BL-P1654 showed good activity against Bacteroides fragilis, but only 60% of strains were susceptible to carbenicillin at achievable blood levels (128 μg/ml). PMID:1041215

Carriers in electron transport from molecular hydrogen to oxygen in Rhizobium japonicum bacteroids.

PubMed Central

Eisbrenner, G; Evans, H J

1982-01-01

An investigation has been conducted to identify electron transport carriers that participate in the oxidation of H2 by H2 uptake-positive strains of Rhizobium japonicum bacteroids. We have observed that the reduced form of dibromothymoquinone at a concentration of 0.2 mM strongly inhibited H2 uptake, endogenous respiration, and C2H2 reduction by bacteroid suspensions. Reduced dibromothymoquinone, however, failed to inhibit the transfer of electrons from H2 to methylene blue under anaerobic conditions, indicating that the hydrogenase per se is insensitive to this inhibitor. Metronidazole, at 1 mM, affected rates of H2 uptake and endogenous respiration only slightly, but strongly inhibited C2H2 reduction. Evidence for H2-dependent cytochrome reduction in an H2 uptake-positive strain of R. japonicum bacteroids is presented. In kinetic studies, the rates of reduction of the type b and c cytochromes in the presence of H2 were shown to be severalfold higher than the rates due to endogenous respiration alone. With hydrogenase-deficient mutants of R. japonicum, no measurable effect of H2 on cytochrome reduction was observed. Our results indicate that ubiquinone and cytochromes of types b and c are involved in the oxyhydrogen reaction in R. japonicum. PMID:6277845

In Vitro Activities of Faropenem against 579 Strains of Anaerobic Bacteria

PubMed Central

Wexler, Hannah M.; Molitoris, Denise; St. John, Shahera; Vu, Ann; Read, Erik K.; Finegold, Sydney M.

2002-01-01

The activity of faropenem, a new oral penem, was tested against 579 strains of anaerobic bacteria by using the NCCLS-approved reference method. Drugs tested included amoxicillin-clavulanate, cefoxitin, clindamycin, faropenem, imipenem, and metronidazole. Of the 176 strains of Bacteroides fragilis group isolates tested, two isolates had faropenem MICs of 64 μg/ml and imipenem MICs of >32 μg/ml. Faropenem had an MIC of 16 μg/ml for an additional isolate of B. fragilis; this strain was sensitive to imipenem (MIC of 1 μg/ml). Both faropenem and imipenem had MICs of ≤4 μg/ml for all isolates of Bacteroides capillosus (10 isolates), Bacteroides splanchnicus (13 isolates), Bacteroides ureolyticus (11 isolates), Bilophila wadsworthia (11 isolates), Porphyromonas species (42 isolates), Prevotella species (78 isolates), Campylobacter species (25 isolates), Sutterella wadsworthensis (11 isolates), Fusobacterium nucleatum (19 isolates), Fusobacterium mortiferum/varium (20 isolates), and other Fusobacterium species (9 isolates). Faropenem and imipenem had MICs of 16 to 32 μg/ml for two strains of Clostridium difficile; the MICs for all other strains of Clostridium tested (69 isolates) were ≤4 μg/ml. Faropenem had MICs of 8 and 16 μg/ml, respectively, for two strains of Peptostreptococcus anaerobius (MICs of imipenem were 2 μg/ml). MICs were ≤4 μg/ml for all other strains of gram-positive anaerobic cocci (53 isolates) and non-spore-forming gram-positive rods (28 isolates). Other results were as expected and reported in previous studies. No metronidazole resistance was seen in gram-negative anaerobes other than S. wadsworthensis (18% resistant); 63% of gram-positive non-spore-forming rods were resistant. Some degree of clindamycin resistance was seen in most of the groups tested. PMID:12384389

[Isolation of anaerobes during a 30-month observation at a hospital microbiology laboratory].

PubMed

Pistono, P G; Rapetti, I; Stacchini, E; Vironda, N; D'Usi, M P; Guasco, C

1989-01-01

The authors evaluate retrospectively the results obtained from the research of anaerobial bacteria on 1313 samples received at the Microbiology Laboratory of the "Ospedale Civile di Ivrea" over a period of 31 months (6/1/86-12/31/88). From this evaluation, high percentages of detection of anaerobic bacteria are emerging in the following infections: appendiculare abscesses (60%), intestinal operations (71%), wounds (57%), tubovarian abscesses (100%), as well as thoracic empyema (50%). Also relevant are the isolations from skin and subcutaneous tissues: breast infections (50%) preputial infections (60%), perineal and perirectal abscesses (60%). The incident of anaerobic bacteria in bacteriemia is 17%. The most representative anaerobic bacteria group are: Bacteroides spp. (56%), Peptostreptococcus spp. (12%), Propionibacterium spp. (9%), Fusobacterium spp. (7%) Clostridium spp. (6%), Veillonella spp. and Eubacterium spp. (3%). In the intraabdominal infections prevails the Bacteroides group, particularly fragilis species, while in the skin and subcutaneous infections prevails the Peptostreptococcus group.

An active principle of Nigella sativa L., thymoquinone, showing significant antimicrobial activity against anaerobic bacteria.

PubMed

Randhawa, Mohammad Akram; Alenazy, Awwad Khalaf; Alrowaili, Majed Gorayan; Basha, Jamith

2017-01-01

Thymoquinone (TQ) is the major active principle of Nigella sativa seed (black seed) and is known to control many fungi, bacteria, and some viruses. However, the activity of TQ against anaerobic bacteria is not well demonstrated. Anaerobic bacteria can cause severe infections, including diarrhea, aspiration pneumonia, and brain abscess, particularly in immunodeficient individuals. The present study aimed to investigate the in vitro antimicrobial activity of TQ against some anaerobic pathogens in comparison to metronidazole. Standard, ATCC, strains of four anaerobic bacteria ( Clostridium difficile , Clostridium perfringens , Bacteroides fragilis , and Bacteroides thetaiotaomicron ), were initially isolated on special Brucella agar base (with hemin and vitamin K). Then, minimum inhibitory concentrations (MICs) of TQ and metronidazole were determined against these anaerobes when grown in Brucella agar, using serial agar dilution method according to the recommended guidelines for anaerobic organisms instructed by the Clinical and Laboratory Standards Institute. TQ showed a significant antimicrobial activity against anaerobic bacteria although much weaker than metronidazole. MICs of TQ and metronidazole against various anaerobic human pathogens tested were found to be between 10-160 mg/L and 0.19-6.25 mg/L, respectively. TQ controlled the anaerobic human pathogenic bacteria, which supports the use of N. sativa in the treatment of diarrhea in folk medicine. Further investigations are in need for determination of the synergistic effect of TQ in combination with metronidazole and the activity of derivatives of TQ against anaerobic infections.

Techniques for controlling variability in gram staining of obligate anaerobes.

PubMed Central

Johnson, M J; Thatcher, E; Cox, M E

1995-01-01

Identification of anaerobes recovered from clinical samples is complicated by the fact that certain gram-positive anaerobes routinely stain gram negative; Peptostreptococcus asaccharolyticus, Eubacterium plautii, Clostridium ramosum, Clostridium symbiosum, and Clostridium clostridiiforme are among the nonconformists with regard to conventional Gram-staining procedures. Accurate Gram staining of American Type Culture Collection strains of these anaerobic bacteria is possible by implementing fixing and staining techniques within a gloveless anaerobic chamber. Under anaerobic conditions, gram-positive staining occurred in all test organisms with "quick" fixing techniques with both absolute methanol and formalin. The results support the hypothesis that, when anaerobic bacteria are exposed to oxygen, a breakdown of the physical integrity of the cell wall occurs, introducing Gram stain variability in gram-positive anaerobes. PMID:7538512

Patient-Specific Bacteroides Genome Variants in Pouchitis

DOE PAGES

Vineis, Joseph H.; Ringus, Daina L.; Morrison, Hilary G.; ...

2016-11-15

Here, a 2-year longitudinal microbiome study of 22 patients who underwent colectomy with an ileal pouch anal anastomosis detected significant increases in distinct populations of Bacteroides during 9 of 11 patient visits that coincided with inflammation (pouchitis). Oligotyping and metagenomic short-read annotation identified Bacteroides populations that occurred in early samples, bloomed during inflammation, and reappeared after antibiotic treatment. Targeted cultivation of Bacteroides isolates from the same individual at multiple time points and from several patients detected subtle genomic changes, including the identification of rapidly evolving genomic elements that differentiate isogenic strains of Bacteroides fragilis from the mucosa versus lumen. Eachmore » patient harbored Bacteroides spp. that are closely related to commonly occurring clinical isolates, including Bacteroides ovatus, B. thetaiotaomicron, B. vulgatus, and B. fragilis, which contained unique loci in different patients for synthesis of capsular polysaccharides. The presence of unique Bacteroides capsular polysaccharide loci within different hosts and between the lumen and mucosa may represent adaptations to stimulate, suppress, and evade host-specific immune responses at different microsites of the ileal pouch.« less

Patient-Specific Bacteroides Genome Variants in Pouchitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vineis, Joseph H.; Ringus, Daina L.; Morrison, Hilary G.

Here, a 2-year longitudinal microbiome study of 22 patients who underwent colectomy with an ileal pouch anal anastomosis detected significant increases in distinct populations of Bacteroides during 9 of 11 patient visits that coincided with inflammation (pouchitis). Oligotyping and metagenomic short-read annotation identified Bacteroides populations that occurred in early samples, bloomed during inflammation, and reappeared after antibiotic treatment. Targeted cultivation of Bacteroides isolates from the same individual at multiple time points and from several patients detected subtle genomic changes, including the identification of rapidly evolving genomic elements that differentiate isogenic strains of Bacteroides fragilis from the mucosa versus lumen. Eachmore » patient harbored Bacteroides spp. that are closely related to commonly occurring clinical isolates, including Bacteroides ovatus, B. thetaiotaomicron, B. vulgatus, and B. fragilis, which contained unique loci in different patients for synthesis of capsular polysaccharides. The presence of unique Bacteroides capsular polysaccharide loci within different hosts and between the lumen and mucosa may represent adaptations to stimulate, suppress, and evade host-specific immune responses at different microsites of the ileal pouch.« less

Comparison of bacteroides-prevotella 16S rRNA genetic markers for fecal samples from different animal species.

PubMed

Fogarty, Lisa R; Voytek, Mary A

2005-10-01

To effectively manage surface and ground waters it is necessary to improve our ability to detect and identify sources of fecal contamination. We evaluated the use of the anaerobic bacterial group Bacteroides-Prevotella as a potential fecal indicator. Terminal restriction length polymorphism (T-RFLP) of the 16S rRNA genes from this group was used to determine differences in populations and to identify any unique populations in chickens, cows, deer, dogs, geese, horses, humans, pigs, and seagulls. The group appears to be a good potential fecal indicator in all groups tested except for avians. Cluster analysis of Bacteroides-Prevotella community T-RFLP profiles indicates that Bacteroides-Prevotella populations from samples of the same host species are much more similar to each other than to samples from different source species. We were unable to identify unique peaks that were exclusive to any source species; however, for most host species, at least one T-RFLP peak was identified to be more commonly found in that species, and a combination of peaks could be used to identify the source. T-RFLP profiles obtained from water spiked with known-source feces contained the expected diagnostic peaks from the source. These results indicate that the approach of identifying Bacteroides-Prevotella molecular markers associated with host species might be useful in identifying sources of fecal contamination in the environment.

Comparison of Bacteroides-Prevotella 16S rRNA Genetic Markers for Fecal Samples from Different Animal Species

PubMed Central

Fogarty, Lisa R.; Voytek, Mary A.

2005-01-01

To effectively manage surface and ground waters it is necessary to improve our ability to detect and identify sources of fecal contamination. We evaluated the use of the anaerobic bacterial group Bacteroides-Prevotella as a potential fecal indicator. Terminal restriction length polymorphism (T-RFLP) of the 16S rRNA genes from this group was used to determine differences in populations and to identify any unique populations in chickens, cows, deer, dogs, geese, horses, humans, pigs, and seagulls. The group appears to be a good potential fecal indicator in all groups tested except for avians. Cluster analysis of Bacteroides-Prevotella community T-RFLP profiles indicates that Bacteroides-Prevotella populations from samples of the same host species are much more similar to each other than to samples from different source species. We were unable to identify unique peaks that were exclusive to any source species; however, for most host species, at least one T-RFLP peak was identified to be more commonly found in that species, and a combination of peaks could be used to identify the source. T-RFLP profiles obtained from water spiked with known-source feces contained the expected diagnostic peaks from the source. These results indicate that the approach of identifying Bacteroides-Prevotella molecular markers associated with host species might be useful in identifying sources of fecal contamination in the environment. PMID:16204514

Comparison of Bacteroides-Prevotella 16S rRNA genetic markers for fecal samples from different animal species

USGS Publications Warehouse

Fogarty, L.R.; Voytek, M.A.

2005-01-01

To effectively manage surface and ground waters it is necessary to improve our ability to detect and identify sources of fecal contamination. We evaluated the use of the anaerobic bacterial group Bacteroides-Prevotella as a potential fecal indicator. Terminal restriction length polymorphism (T-RFLP) of the 16S rRNA genes from this group was used to determine differences in populations and to identify any unique populations in chickens, cows, deer, dogs, geese, horses, humans, pigs, and seagulls. The group appears to be a good potential fecal indicator in all groups tested except for avians. Cluster analysis of Bacteroides-Prevotella community T-RFLP profiles indicates that Bacteroides-Prevotella populations from samples of the same host species are much more similar to each other than to samples from different source species. We were unable to identify unique peaks that were exclusive to any source species; however, for most host species, at least one T-RFLP peak was identified to be more commonly found in that species, and a combination of peaks could be used to identify the source. T-RFLP profiles obtained from water spiked with known-source feces contained the expected diagnostic peaks from the source. These results indicate that the approach of identifying Bacteroides-Prevotella molecular markers associated with host species might be useful in identifying sources of fecal contamination in the environment.

Isolation of non-sporing anaerobic rods from infections in children.

PubMed

Brook, I

1996-07-01

From 1974 to 1994, 2033 microbiological specimens from children were submitted for cultures for anaerobic bacteria. Fifty-seven isolates of Bifidobacterium spp. were obtained from 55 (3%) children, 67 isolates of Eubacterium spp. from 65 (3%) children and 41 isolates of Lactobacillus spp. from 40 (2%) children. Most Bifidobacterium isolates were from chronic otitis media, abscesses, peritonitis, aspiration pneumonia and paronychia. Most Eubacterium isolates were from abscesses, peritonitis, decubitus ulcers and bites. Lactobacillus spp. were mainly isolated from abscesses, aspiration pneumonia, bacteraemia and conjunctivitis. Most (> 90%) infections from which these species were isolated were polymicrobial and yielded a mixture of aerobic and anaerobic bacteria. The organisms most commonly isolated with the non-sporing anaerobic gram-positive rods were Peptostreptococcus spp., Bacteroides spp., pigmented Prevotella and Porphyromonas spp., Fusobacterium spp., Staphylococcus aureus and Escherichia coli. Most Bacteroides spp. and E. coli were isolated from intra-abdominal infection and skin and soft tissue infection around the rectal area, whereas most Prevotella, Porphyromonas and Fusobacterium isolates were from oropharyngeal, pulmonary and head and neck sites. The predisposing conditions associated with the isolation of non-sporing anaerobic gram-positive rods were previous surgery, malignancy, steroid therapy and immunodeficiency. Antimicrobial therapy was given to 149 (83%) of the 160 patients, in conjunction with surgical drainage or correction of pathology in 89 (56%).

Antimicrobial susceptibility of clinical isolates of anaerobic bacteria in Ontario, 2010-2011.

PubMed

Marchand-Austin, Alex; Rawte, Prasad; Toye, Baldwin; Jamieson, Frances B; Farrell, David J; Patel, Samir N

2014-08-01

The local epidemiology of antimicrobial susceptibility patterns in anaerobic bacteria is important in guiding the empiric treatment of infections. However, susceptibility data are very limited on anaerobic organisms, particularly among non-Bacteroides organisms. To determine susceptibility profiles of clinically-significant anaerobic bacteria in Ontario Canada, anaerobic isolates from sterile sites submitted to Public Health Ontario Laboratory (PHOL) for identification and susceptibility testing were included in this study. Using the E-test method, isolates were tested for various antimicrobials including, penicillin, cefoxitin, clindamycin, meropenem, piperacillin-tazobactam and metronidazole. The MIC results were interpreted based on guidelines published by Clinical and Laboratory Standards Institute. Of 2527 anaerobic isolates submitted to PHOL, 1412 were either from sterile sites or bronchial lavage, and underwent susceptibility testing. Among Bacteroides fragilis, 98.2%, 24.7%, 1.6%, and 1.2% were resistant to penicillin, clindamycin, piperacillin-tazobactam, and metronidazole, respectively. Clostridium perfringens was universally susceptible to penicillin, piperacillin-tazobactam, and meropenem, whereas 14.2% of other Clostridium spp. were resistant to penicillin. Among Gram-positive anaerobes, Actinomyces spp., Parvimonas micra and Propionibacterium spp. were universally susceptible to β-lactams. Eggerthella spp., Collinsella spp., and Eubacterium spp. showed variable resistance to penicillin. Among Gram-negative anaerobes, Fusobacterium spp., Prevotella spp., and Veillonella spp. showed high resistance to penicillin but were universally susceptible to meropenem and piperacillin-tazobactam. The detection of metronidazole resistant B. fragilis is concerning as occurrence of these isolates is extremely rare. These data highlight the importance of ongoing surveillance to provide clinically relevant information to clinicians for empiric management of

Suppurative otitis and ascending meningoencephalitis associated with Bacteroides tectus and Porphyromonas gulae in a captive Parma wallaby (Macropus parma) with toxoplasmosis.

PubMed

Giannitti, Federico; Schapira, Andrea; Anderson, Mark; Clothier, Kristin

2014-09-01

A 6-year-old female Parma wallaby (Macropus parma) at a zoo in California developed acute ataxia and left-sided circling. Despite intensive care, clinical signs progressed to incoordination and prostration, and the animal was euthanized. At necropsy, the left tympanic cavity was filled with homogeneous suppurative exudate that extended into the cranium expanding the meninges and neuroparenchyma in the lateral and ventral aspect of the caudal ipsilateral brainstem and medulla oblongata. Microscopically, the brainstem showed regional severe suppurative meningoencephalitis with large numbers of neutrophils, fewer macrophages, and lymphocytes admixed with fibrin, necrotic cellular debris, hemorrhage, and mineralization, with numerous intralesional Gram-negative bacilli. Bacteroides spp. and Porphyromonas spp. were isolated on anaerobic culture from the meninges, and the bacteria were further characterized by partial 16S ribosomal RNA gene sequencing as Bacteroides tectus and Porphyromonas gulae. Bacterial aerobic culture from the meninges yielded very low numbers of mixed flora and Proteus spp., which were considered contaminants. Culture of Mycoplasma spp. from middle ear and meninges was negative. Additionally, Toxoplasma gondii cysts were detected by immunohistochemistry in the heart and brain, and anti-Toxoplasma antibodies were detected in serum. The genera Bacteroides and Porphyromonas have been associated with oral disease in marsupials; but not with otitis and meningoencephalitis. The results of the present work highlight the importance of performing anaerobic cultures in the diagnostic investigation of cases of suppurative otitis and meningoencephalitis in macropods. © 2014 The Author(s).

Bacterial ecology of abattoir wastewater treated by an anaerobic digestor

PubMed Central

Jabari, Linda; Gannoun, Hana; Khelifi, Eltaief; Cayol, Jean-Luc; Godon, Jean-Jacques; Hamdi, Moktar; Fardeau, Marie-Laure

2016-01-01

Wastewater from an anaerobic treatment plant at a slaughterhouse was analysed to determine the bacterial biodiversity present. Molecular analysis of the anaerobic sludge obtained from the treatment plant showed significant diversity, as 27 different phyla were identified. Firmicutes, Proteobacteria, Bacteroidetes, Thermotogae, Euryarchaeota (methanogens), and msbl6 (candidate division) were the dominant phyla of the anaerobic treatment plant and represented 21.7%, 18.5%, 11.5%, 9.4%, 8.9%, and 8.8% of the total bacteria identified, respectively. The dominant bacteria isolated were Clostridium, Bacteroides, Desulfobulbus, Desulfomicrobium, Desulfovibrio and Desulfotomaculum. Our results revealed the presence of new species, genera and families of microorganisms. The most interesting strains were characterised. Three new bacteria involved in anaerobic digestion of abattoir wastewater were published. PMID:26887229

[Significance of the bacterial flora in the etiology of apical periodontitis. Qualitative, quantitative and topographical aspects].

PubMed

Accorsi, S; Lavagnoli, G; Frigeri, S; Fiamminghi, L

1990-01-01

In the international literature it is shown the central role of root canal infection in the etiology of periapical lesions. As a matter of fact it has been proved (13) that sterile necrotic pulp tissue is completely unable to cause inflammatory reactions at the periapex. Infection of endodontic origin extends to the supporting tissues of the tooth only in the case of their acute inflammation (e.g. acute apical periodontitis, acute alveolar abscess, phoenix abscess). On the other hand in chronic inflammation bacteria remain confined in the endodontic space. Only few exceptions to this general rule have been experimentally proved. In endodontics we deal with a mixed infection which is composed by obligate anaerobes and by facultative anaerobes. The most frequently found obligate anaerobes are Bacteroides sp. and Fusobacterium sp. (Gram- rods) Anaerobic Diphtheroides (Gram+ rods) Peptostreptococcus sp. (Gram+ cocci) and Veilonella sp. (Gram- cocci). Actinomyces sp., Lactobacillus sp., Streptococcus sp., and Staphilococcus sp. are the facultative anaerobes most frequently found.

Studies into the microbial spectrum of apical periodontitis.

PubMed

Brauner, A W; Conrads, G

1995-09-01

This study examined the variety of obligate and facultative anaerobic bacterial species recovered from cases of acute apical periodontitis. A total of 19 root canal samples and 24 periapical granuloma samples were taken from patients suffering pain and discomfort. Bacteria were identified by applying the following techniques: culturing on various media, Gram-staining and using commercially available biochemical test strips. In addition, Prevotella intermedia and Porphyromonas endodontalis were differentiated on a molecular genetic level using species-specific oligodeoxynucleotide probes. The most frequently identified bacteria were Prevotella intermedia, Bifidobacterium spp., Streptococcus sanguis, Streptococcus milleri-group and Bacteroides spp. Obligate anaerobes occurred at a rate of 82.3%, and the average number of isolates was 6.4 per sample.

Quantitative studies on the vaginal flora of asymptomatic women and patients with vaginitis and vaginosis.

PubMed

Hammann, R; Kronibus, A; Lang, N; Werner, H

1987-07-01

Vaginal washings of 22 patients with vaginitis, 11 with vaginosis, and 12 healthy subjects were investigated quantitatively and qualitatively for aerobic and anaerobic bacteria and yeasts. Gardnerella vaginalis was recovered from 9 of the vaginitis patients, 7 of the vaginosis patients, and 4 of the asymptomatic subjects. Obligate anaerobes were found in 11 of the vaginitis patients, 4 of the vaginosis patients, and none of the control subjects. Bacteroides bivius was the anaerobe most frequently isolated from symptomatic subjects. Anaerobic vibrios were recovered twice from symptomatic subjects. The counts for Gardnerella vaginalis and anaerobes when present were generally very high. The most frequent aerobes were beta-hemolytic streptococci (group B) and staphylococci.

Isolation and reconstitution of iron- and manganese-containing superoxide dismutases from Bacteroides thetaiotaomicron.

PubMed Central

Pennington, C D; Gregory, E M

1986-01-01

Superoxide dismutase (SOD) from extracts of anaerobically maintained Bacteroides thetaiotaomicron was a dimer of equally sized 23,000-molecular-weight monomers joined noncovalently. A preparation with a specific activity of 1,200 U/mg contained 1.1 g-atom of Fe, 0.6 g-atom of Zn, and less than 0.05 g-atom of Mn per mol of dimer. The apoprotein, prepared by dialysis of iron-SOD in 5 M guanidinium chloride-20 mM 8-hydroxyquinoline, had no superoxide-scavenging activity when renatured without exogenous metal. Enzymatic activity was restored to the denatured apoprotein by dialysis against either 1 mM Fe(NH4)2 or 1 mM MnCl2 in 20 mM Tris (pH 7.0). The Fe-reconstituted enzyme and the native enzyme were inhibited approximately 50% by 0.2 mM NaN3, whereas the Mn-reconstituted enzyme was inhibited 60% by 10 mM NaN3. Aeration of the anaerobic cells resulted in a fourfold induction of an azide-resistant SOD. The enzyme (43,000 molecular weight) isolated from aerated cells was a dimer of equally sized subunits. The metal content was 1.0 g-atom of Mn, 0.55 g-atom of Fe, and 0.3 g-atom of Zn per mol of dimer. Enzymatic activity of the denatured apoprotein from this enzyme was also restored on addition of either iron or manganese. The constitutive Fe-SOD and the O2-induced Mn-SOD, tested alone and in combination, migrated identically on acrylamide gels, had similar amino acid compositions, and had alanine as the sole N-terminal amino acid. These data are consistent with the synthesis of a single apoprotein in either anaerobically maintained or oxygenated cells. We have observed a similar phenomenon with SOD from Bacteroides fragilis (E. M. Gregory, Arch. Biochem. Biophys. 238:83-89, 1985). PMID:3700336

The Fumarate Reductase of Bacteroides thetaiotaomicron, unlike That of Escherichia coli, Is Configured so that It Does Not Generate Reactive Oxygen Species

PubMed Central

Lu, Zheng

2017-01-01

ABSTRACT The impact of oxidative stress upon organismal fitness is most apparent in the phenomenon of obligate anaerobiosis. The root cause may be multifaceted, but the intracellular generation of reactive oxygen species (ROS) likely plays a key role. ROS are formed when redox enzymes accidentally transfer electrons to oxygen rather than to their physiological substrates. In this study, we confirm that the predominant intestinal anaerobe Bacteroides thetaiotaomicron generates intracellular ROS at a very high rate when it is aerated. Fumarate reductase (Frd) is a prominent enzyme in the anaerobic metabolism of many bacteria, including B. thetaiotaomicron, and prior studies of Escherichia coli Frd showed that the enzyme is unusually prone to ROS generation. Surprisingly, in this study biochemical analysis demonstrated that the B. thetaiotaomicron Frd does not react with oxygen at all: neither superoxide nor hydrogen peroxide is formed. Subunit-swapping experiments indicated that this difference does not derive from the flavoprotein subunit at which ROS normally arise. Experiments with the related enzyme succinate dehydrogenase discouraged the hypothesis that heme moieties are responsible. Thus, resistance to oxidation may reflect a shift of electron density away from the flavin moiety toward the iron-sulfur clusters. This study shows that the autoxidizability of a redox enzyme can be suppressed by subtle modifications that do not compromise its physiological function. One implication is that selective pressures might enhance the oxygen tolerance of an organism by manipulating the electronic properties of its redox enzymes so they do not generate ROS. PMID:28049145

Isolation and characterisation of obligately anaerobic, lipolytic bacteria from the rumen of red deer.

PubMed

Jarvis, G N; Strömpl, C; Moore, E R; Thiele, J H

1998-03-01

Two Gram-positive, obligately anaerobic, lipolytic bacteria, isolates LIP4 and LIP5, were obtained from the rumen contents of juvenile red deer. These mesophilic bacterial strains were capable of hydrolysing the neutral lipids, tallow, tripalmitin and oliver oil, into their constituent free long-chain fatty acid and glycerol moieties. The latter compound was dissimilated by both isolates, with isolate LIP4 producing propionate as the predominant product, while isolate LIP5 produced acetate, ethanol and succinate. The lactate-utilising isolate LIP4 grew on a limited range of saccharide substrates including glucose, fructose and ribose, and exhibited an unusual cell wall structure and morphology. The isolate LIP5 grew upon a wider range of saccharides, but was unable to use lactate as a substrate. Based upon phenotypic and 16S rRNA gene sequence analyses, isolate LIP4 clusters with species in the genus Propionibacterium, while isolate LIP5 is a member of clostridial cluster XIVa.

Anaerobic bacteria growth in the presence of cathelicidin LL-37 and selected ceragenins delivered as magnetic nanoparticles cargo.

PubMed

Durnaś, Bonita; Piktel, Ewelina; Wątek, Marzena; Wollny, Tomasz; Góźdź, Stanisław; Smok-Kalwat, Jolanta; Niemirowicz, Katarzyna; Savage, Paul B; Bucki, Robert

2017-07-26

Cationic antibacterial peptides (CAPs) and synthetic molecules mimicking the amphiphilic structure of CAPs, such as ceragenins, are promising compounds for the development of new antimicrobials. We tested the in vitro activity of ceragenins CSA-13 and CSA-131 against several anaerobic bacteria including Bacteroides spp. and Clostridium difficile. We compared results to the activity of cathelicidin LL-37, metronidazole and nanosystems developed by attachment of CSA-13 and CSA-131 to magnetic nanoparticles (MNPs). The antibacterial effect was tested using killing assay and modified CLSI broth microdilution assay. Ceragenins CSA-13 and CSA-131 displayed stronger bactericidal activity than LL-37 or metronidazole against all of the tested bacterial strains. Additionally CSA-131 revealed an enhanced ability to prevent the formation of Bacteroides fragilis and Propionibacterium acnes biofilms. These data confirmed that ceragenins display antimicrobial activity against a broad range of microorganisms including anaerobic bacteria and deserve further investigations as compounds serving to develop new treatment against anaerobic and mixed infections.

[In vitro activities of sulopenem, a new parenteral penem, against anaerobes].

PubMed

Watanabe, K; Kato, N; Tanaka-Bandoh, K; Tanaka, Y; Kato, H; Ueno, K

1996-04-01

In vitro activities of sulopenem, a novel parenteral penem, was compared with those of imipenem, flomoxef, cefuzonam, cefoperazone and sulbactam/ampicillin against 66 reference strains (19 genera, 61 species) and 392 recent clinical isolates of anaerobic bacteria and fastidious aerobic bacteria. Sulopenem had a very broad spectrum against anaerobic bacteria. In general, this compound was active against anaerobic reference strains with MICs of < or = 0.78 micrograms/ml, while being the least active against Bifidobacterium spp. and less active than imipenem against Lactobacillus spp. Sulopenem was more active against Bacteroides fragilis isolates than imipenem and had the highest activities against Bacteroides thetaiotaomicron, Prevotella intermedia, Porphyromonas gingivalis, Fusobacterium spp. and Peptostreptococcus spp. among the antibiotics tested. Sulopenem was not hydrolyzed by oxyiminocephalosporinase type 1 produced by B. fragilis GAI-0558, GAI-7955 and GAI-10150 and its stability was comparable to imipenem. Its susceptibilities to hydrolysis by a metallo-beta-lactamase from B. fragilis GAI-30144 was less than imipenem. Sulopenem (120 mg/kg, 3 times a day for 4 days) was as effective as imipenem/cilastatin against a mixed intraabdominal mice infection due to E. coli and B. fragilis. Sulopenem (20 mg/kg twice a day for 5 days) did not induce an overgrowth of Clostridium difficile in the caecum of mice.

Comparative In Vitro Activities of ABT-773 against 362 Clinical Isolates of Anaerobic Bacteria

PubMed Central

Citron, Diane M.; Appleman, Maria D.

2001-01-01

The activity of ABT-773, a novel ketolide antibiotic, against clinical isolates of anaerobic bacteria was determined and compared to the activities of other antimicrobial agents. MICs at which 90% of isolates were inhibited (MIC90s) were ≤0.06 μg/ml for Actinomyces spp., Clostridium perfringens, Peptostreptococcus spp., Propionibacterium spp., and Porphyromonas spp. The MIC50s and MIC90s were ≤0.06 and >32 μg/ml, respectively, for Eubacterium spp., Lactobacillus spp., Clostridium difficile, and Clostridium ramosum. The MIC90 for Bilophila wadsworthia, Bacteroides ureolyticus, and Campylobacter gracilis was 1 μg/ml, and that for Prevotella bivia and other Prevotella spp. was 0.5 μg/ml. The MIC90 for Fusobacterium nucleatum was 8 μg/ml, and that for Fusobacterium mortiferum and Fusobacterium varium was >32 μg/ml. The MIC90s for the Bacteroides fragilis group were as follows: for B. fragilis, 8 μg/ml; for Bacteroides thetaiotaomicron, Bacteroides ovatus, Bacteroides distasonis, and Bacteroides uniformis, >32 μg/ml; and for Bacteroides vulgatus, 4 μg/ml. Telithromycin MICs for the B. fragilis group were usually 1 to 2 dilutions higher than ABT-773 MICs. For all strains, ABT-773 was more active than erythromycin by 4 or more dilutions, and for some strains this drug was more active than clindamycin. PMID:11120995

Phylogeny of Bacteroides, Prevotella, and Porphyromonas spp. and related bacteria.

PubMed Central

Paster, B J; Dewhirst, F E; Olsen, I; Fraser, G J

1994-01-01

The phylogenetic structure of the bacteroides subgroup of the cytophaga-flavobacter-bacteroides (CFB) phylum was examined by 16S rRNA sequence comparative analysis. Approximately 95% of the 16S rRNA sequence was determined for 36 representative strains of species of Prevotella, Bacteroides, and Porphyromonas and related species by a modified Sanger sequencing method. A phylogenetic tree was constructed from a corrected distance matrix by the neighbor-joining method, and the reliability of tree branching was established by bootstrap analysis. The bacteroides subgroup was divided primarily into three major phylogenetic clusters which contained most of the species examined. The first cluster, termed the prevotella cluster, was composed of 16 species of Prevotella, including P. melaninogenica, P. intermedia, P. nigrescens, and the ruminal species P. ruminicola. Two oral species, P. zoogleoformans and P. heparinolytica, which had been recently placed in the genus Prevotella, did not fall within the prevotella cluster. These two species and six species of Bacteroides, including the type species B. fragilis, formed the second cluster, termed the bacteroides cluster. The third cluster, termed the porphyromonas cluster, was divided into two subclusters. The first contained Porphyromonas gingivalis, P. endodontalis, P. asaccharolytica, P. circumdentaria, P. salivosa, [Bacteroides] levii (the brackets around genus are used to indicate that the species does not belong to the genus by the sensu stricto definition), and [Bacteroides] macacae, and the second subcluster contained [Bacteroides] forsythus and [Bacteroides] distasonis. [Bacteroides] splanchnicus fell just outside the three major clusters but still belonged within the bacteroides subgroup. With few exceptions, the 16 S rRNA data were in overall agreement with previously proposed reclassifications of species of Bacteroides, Prevotella, and Porphyromonas. Suggestions are made to accommodate those species which do not

In vitro activity of ceftaroline against 623 diverse strains of anaerobic bacteria.

PubMed

Citron, D M; Tyrrell, K L; Merriam, C V; Goldstein, E J C

2010-04-01

The in vitro activities of ceftaroline, a novel, parenteral, broad-spectrum cephalosporin, and four comparator antimicrobials were determined against anaerobic bacteria. Against Gram-positive strains, the activity of ceftaroline was similar to that of amoxicillin-clavulanate and four to eight times greater than that of ceftriaxone. Against Gram-negative organisms, ceftaroline showed good activity against beta-lactamase-negative strains but not against the members of the Bacteroides fragilis group. Ceftaroline showed potent activity against a broad spectrum of anaerobes encountered in respiratory, skin, and soft tissue infections.

Bacterial ecology of abattoir wastewater treated by an anaerobic digestor.

PubMed

Jabari, Linda; Gannoun, Hana; Khelifi, Eltaief; Cayol, Jean-Luc; Godon, Jean-Jacques; Hamdi, Moktar; Fardeau, Marie-Laure

2016-01-01

Wastewater from an anaerobic treatment plant at a slaughterhouse was analysed to determine the bacterial biodiversity present. Molecular analysis of the anaerobic sludge obtained from the treatment plant showed significant diversity, as 27 different phyla were identified. Firmicutes, Proteobacteria, Bacteroidetes, Thermotogae, Euryarchaeota (methanogens), and msbl6 (candidate division) were the dominant phyla of the anaerobic treatment plant and represented 21.7%, 18.5%, 11.5%, 9.4%, 8.9%, and 8.8% of the total bacteria identified, respectively. The dominant bacteria isolated were Clostridium, Bacteroides, Desulfobulbus, Desulfomicrobium, Desulfovibrio and Desulfotomaculum. Our results revealed the presence of new species, genera and families of microorganisms. The most interesting strains were characterised. Three new bacteria involved in anaerobic digestion of abattoir wastewater were published. Copyright © 2015 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Evaluation of the routine antimicrobial susceptibility testing results of clinically significant anaerobic bacteria in a Slovenian tertiary-care hospital in 2015.

PubMed

Jeverica, Samo; Kolenc, Urša; Mueller-Premru, Manica; Papst, Lea

2017-10-01

The aim of our study was to determined antimicrobial susceptibility profiles of 2673 clinically significant anaerobic bacteria belonging to the major genera, isolated in 2015 in a large tertiary-care hospital in Slovenia. The species identification was performed by MALDI-TOF mass spectrometry. Antimicrobial susceptibility was determined immediately at the isolation of the strains against: penicillin, co-amoxiclav, imipenem, clindamycin and metronidazole, using gradient diffusion methodology and EUCAST breakpoints. The most frequent anaerobes were Bacteroides fragilis group with 31% (n = 817), Gram positive anaerobic cocci (GPACs) with 22% (n = 589), Prevotella with 14% (n = 313) and Propionibacterium with 8% (n = 225). Metronidazole has retained full activity (100%) against all groups of anaerobic bacteria intrinsically susceptible to it. Co-amoxiclav and imipenem were active against most tested anaerobes with zero or low resistance rates. However, observed resistance to co-amoxiclav (8%) and imipenem (1%) is worrying especially among B. fragilis group isolates. High overall resistance (23%) to clindamycin was detected in our study and was highest among the genera Prevotella, Bacteroides, Parabacteroides, GPACs and Clostridium. Routine testing of antimicrobial susceptibility of clinically relevant anaerobic bacteria is feasible and provides good surveillance data. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Induction of oxidative DNA damage in anaerobes.

PubMed

Takeuchi, T; Nakaya, Y; Kato, N; Watanabe, K; Morimoto, K

1999-05-07

We compared oxidative DNA damage in strictly anaerobic Prevotella melaninogenica, aerotolerant anaerobic Bacteroides fragilis, and facultative anaerobic Salmonella typhimurium after exposure to O2 or H2O2. Using HPLC with electrochemical detection, we measured 8-hydroxydeoxyguanosine (8OHdG) as a damage marker. O2 induced 8OHdG in P. melaninogenica but not in B. fragilis, which shows catalase activity, or in S. typhimurium. In P. melaninogenica, with catalase, O2 induced less 8OHdG; superoxide dismutase had no effect; with glucose and glucose oxidase, O2 induced more 8OHdG. H2O2 also markedly increased 8OHdG. O2 was suggested to induce 8OHdG through H2O2. O2 or H2O2 decreased survival only in P. melaninogenica. Highly sensitive to oxidative stress, P. melaninogenica could prove useful for investigating oxidative DNA damage.

Immunomodulatory effects of Bacteroides products on in vitro human lymphocyte functions.

PubMed

Shenker, B J; Slots, J

1989-03-01

Bacteroides spp. have been implicated in the pathogenesis of several diseases, including periodontal diseases. In this study sonic extracts of 6 Bacteroides spp. were examined for their abilities to alter human lymphocyte function. We found that soluble extracts from Bacteroides intermedius, Bacteroides endodontalis, Bacteroides asaccharolyticus, Bacteroides melaninogenicus, and to a lesser degree Bacteroides loescheii, caused dose-dependent inhibition of human lymphocyte responsiveness to both mitogens and antigens. Suppression involved altered DNA, RNA and protein synthesis as well as immunoglobulin production. In contrast, Bacteroides gingivalis did not suppress these responses; instead, it stimulated lymphocyte proliferation and enhanced immunoglobulin production. It has been proposed that impaired host defense may play a pivotal role in the pathogenesis of many infections. The data presented in this paper suggest that microbial mediated immunosuppression may conceivably alter the nature and consequences of host-parasite interactions in periodontal disease.

Multi-centre evaluation of mass spectrometric identification of anaerobic bacteria using the VITEK® MS system.

PubMed

Garner, O; Mochon, A; Branda, J; Burnham, C-A; Bythrow, M; Ferraro, M; Ginocchio, C; Jennemann, R; Manji, R; Procop, G W; Richter, S; Rychert, J; Sercia, L; Westblade, L; Lewinski, M

2014-04-01

Accurate and timely identification of anaerobic bacteria is critical to successful treatment. Classic phenotypic methods for identification require long turnaround times and can exhibit poor species level identification. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is an identification method that can provide rapid identification of anaerobes. We present a multi-centre study assessing the clinical performance of the VITEK(®) MS in the identification of anaerobic bacteria. Five different test sites analysed a collection of 651 unique anaerobic isolates comprising 11 different genera. Multiple species were included for several of the genera. Briefly, anaerobic isolates were applied directly to a well of a target plate. Matrix solution (α-cyano-4-hydroxycinnamic acid) was added and allowed to dry. Mass spectra results were generated with the VITEK(®) MS, and the comparative spectral analysis and organism identification were determined using the VITEK(®) MS database 2.0. Results were confirmed by 16S rRNA gene sequencing. Of the 651 isolates analysed, 91.2% (594/651) exhibited the correct species identification. An additional eight isolates were correctly identified to genus level, raising the rate of identification to 92.5%. Genus-level identification consisted of Actinomyces, Bacteroides and Prevotella species. Fusobacterium nucleatum, Actinomyces neuii and Bacteroides uniformis were notable for an increased percentage of no-identification results compared with the other anaerobes tested. VITEK(®) MS identification of clinically relevant anaerobes is highly accurate and represents a dramatic improvement over other phenotypic methods in accuracy and turnaround time. © 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.

[Antimicrobial susceptibility testing of anaerobic bacteria].

PubMed

García-Sánchez, José E; García-Sánchez, Enrique; García-García, María Inmaculada

2014-02-01

The anaerobic bacteria resistance to antibiotics is increasing, and even has appeared against the most active of those, like metronidazol and carbapenems. This fact forces to make and periodical sensibility tests -at least in the most aggressive and virulent species, in cases that they are isolated from life locations and in the absence of therapeutic response- to check the local sensibility and to establish suitable empiric therapies, all based on multicentric studies carried out in order to this or well to check the activity of new antibiotics. For the laboratory routine, the easiest sensibility method is the E-test/MIC evaluator. Another alternative is microdilution, that's only normalized for Bacteroides. There are preliminary facts that allow the use of disc diffusion method in some species of Bacteroides and Clostridium. For the temporal and multicentric studies, the procedure is dilution in agar plate, the reference method. Copyright © 2014 Elsevier España, S.L. All rights reserved.

Adaptation of the Biolog Phenotype MicroArrayTM Technology to Profile the Obligate Anaerobe Geobacter metallireducens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joyner, Dominique; Fortney, Julian; Chakraborty, Romy

2010-05-17

The Biolog OmniLog? Phenotype MicroArray (PM) plate technology was successfully adapted to generate a select phenotypic profile of the strict anaerobe Geobacter metallireducens (G.m.). The profile generated for G.m. provides insight into the chemical sensitivity of the organism as well as some of its metabolic capabilities when grown with a basal medium containing acetate and Fe(III). The PM technology was developed for aerobic organisms. The reduction of a tetrazolium dye by the test organism represents metabolic activity on the array which is detected and measured by the OmniLog(R) system. We have previously adapted the technology for the anaerobic sulfate reducingmore » bacterium Desulfovibrio vulgaris. In this work, we have taken the technology a step further by adapting it for the iron reducing obligate anaerobe Geobacter metallireducens. In an osmotic stress microarray it was determined that the organism has higher sensitivity to impermeable solutes 3-6percent KCl and 2-5percent NaNO3 that result in osmotic stress by osmosis to the cell than to permeable non-ionic solutes represented by 5-20percent ethylene glycol and 2-3percent urea. The osmotic stress microarray also includes an array of osmoprotectants and precursor molecules that were screened to identify substrates that would provide osmotic protection to NaCl stress. None of the substrates tested conferred resistance to elevated concentrations of salt. Verification studies in which G.m. was grown in defined medium amended with 100mM NaCl (MIC) and the common osmoprotectants betaine, glycine and proline supported the PM findings. Further verification was done by analysis of transcriptomic profiles of G.m. grown under 100mM NaCl stress that revealed up-regulation of genes related to degradation rather than accumulation of the above-mentioned osmoprotectants. The phenotypic profile, supported by additional analysis indicates that the accumulation of these osmoprotectants as a response to salt stress does

Evaluation of the RapID-ANA system for identification of anaerobic bacteria of veterinary origin.

PubMed

Adney, W S; Jones, R L

1985-12-01

This study evaluated the ability of the RapID-ANA system (Innovative Diagnostic Systems, Inc., Atlanta, Ga.) to accurately identify a spectrum of freshly isolated veterinary anaerobes. A total of 183 isolates were tested and included 7 Actinomyces spp., 53 Bacteroides spp., 32 Clostridium spp., 2 Eubacterium spp., 65 Fusobacterium spp., 1 Peptococcus spp., 22 Peptostreptococcus spp., and 1 Propionibacterium spp. All isolates were initially identified by conventional biochemical testing and gas-liquid chromatography of short-chain fatty acid metabolites. Additional tests were performed as required by the RapID-ANA system. Of these isolates, 81.4% were correctly identified to the genus level, including 59.6% to the species level, 14.2% were incorrectly identified at the genus level, and 4.4% were not identified. Initially, 20.2% of the strains were not identified because the microcodes were not in the code book. The majority of the incorrect identifications were caused by the misidentification of Fusobacterium spp. as Bacteroides spp. Errors also occurred when veterinary anaerobes not included in the data base were assigned an identification from the existing data base. The RapID-ANA system appears to be a promising new method for rapid identification of veterinary anaerobes; however, further evaluation with an extended data base is needed before the system can accurately identify all clinically significant anaerobes.

Butyl Rubber Stoppers Increase the Shelf Life of Prereduced, Anaerobically Sterilized Media

PubMed Central

Fulghum, Robert S.; Worthington, John M.

1977-01-01

Butyl rubber stoppers as compared with neoprene or black rubber stoppers significantly increased the shelf life of prereduced, anaerobically sterilized media for growth of obligately anaerobic bacteria. PMID:879778

Anaerobic bacteria that dechlorinate perchloroethene.

PubMed Central

Fathepure, B Z; Nengu, J P; Boyd, S A

1987-01-01

In this study, we identified specific cultures of anaerobic bacteria that dechlorinate perchlorethene (PCE). The bacteria that significantly dechlorinated PCE were strain DCB-1, an obligate anaerobe previously shown to dechlorinate chlorobenzoate, and two strains of Methanosarcina. The rate of PCE dechlorination by DCB-1 compared favorably with reported rates of trichloroethene bio-oxidation by methanotrophs. Even higher PCE dechlorination rates were achieved when DCB-1 was grown in a methanogenic consortium. PMID:3426224

Preliminary report on anaerobic culture at Mymensingh Medical College Hospital in Bangladesh.

PubMed

Ahmed, S; Hossain, M A; Musa, A K; Shamsuzzaman, A K; Mahmud, M C; Nahar, K; Paul, S K; Sumona, A A; Begum, Z; Zahan, N A; Huda, S N; Ahmed, M U; Khan, A H; Kalam, A; Haque, N; Nasrin, S A

2010-01-01

Puerperal sepsis is an important cause of maternal morbidity and mortality in developing countries. This study was undertaken to isolate and identify the anaerobic bacterial agents of puerperal sepsis among the patients admitted in Mymensingh Medical College Hospital (MMCH) during the period from July 2006 to June 2007. Endocervical swabs/secretions were collected from 50 cases of puerperal sepsis and were cultured anaerobically. Anaerobiasis was done by using gas pack (BD GAS PAK TM EZ) in anaerobic jar. Out of 50 samples, 42(84%) yielded growth in cultures. Among 42 culture positive cases, 20(40%) were Aerobic organisms and 22(44%) were mixed, i.e., Aerobic and Anaerobic bacteria. The isolated Anaerobic organisms were Peptostreptococcus 14(63.63%), Bacteroides fragilis 3(13.64%), Prevotella melaninogenica 3(13.64%) and Clostridium perfringens 2(9.09%). As a preliminary study, it was observed that anaerobic culture could be carried out with available logistic arrangement. So, it was recommended to design further study on anaerobic bacterial isolation with particular emphasis on their antimicrobial susceptibility.

Defining the bacteroides ribosomal binding site.

PubMed

Wegmann, Udo; Horn, Nikki; Carding, Simon R

2013-03-01

The human gastrointestinal tract, in particular the colon, hosts a vast number of commensal microorganisms. Representatives of the genus Bacteroides are among the most abundant bacterial species in the human colon. Bacteroidetes diverged from the common line of eubacterial descent before other eubacterial groups. As a result, they employ unique transcription initiation signals and, because of this uniqueness, they require specific genetic tools. Although some tools exist, they are not optimal for studying the roles and functions of these bacteria in the human gastrointestinal tract. Focusing on translation initiation signals in Bacteroides, we created a series of expression vectors allowing for different levels of protein expression in this genus, and we describe the use of pepI from Lactobacillus delbrueckii subsp. lactis as a novel reporter gene for Bacteroides. Furthermore, we report the identification of the 3' end of the 16S rRNA of Bacteroides ovatus and analyze in detail its ribosomal binding site, thus defining a core region necessary for efficient translation, which we have incorporated into the design of our expression vectors. Based on the sequence logo information from the 5' untranslated region of other Bacteroidales ribosomal protein genes, we conclude that our findings are relevant to all members of this order.

The Bacteroid Periplasm in Soybean Nodules Is an Interkingdom Symbiotic Space.

PubMed

Strodtman, Kent N; Stevenson, Severin E; Waters, James K; Mawhinney, Thomas P; Thelen, Jay J; Polacco, Joseph C; Emerich, David W

2017-12-01

The functional role of the periplasm of nitrogen-fixing bacteroids has not been determined. Proteins were isolated from the periplasm and cytoplasm of Bradyrhizobium diazoefficiens bacteroids and were analyzed using liquid chromatography tandem mass spectrometry proteomics. Identification of bacteroid periplasmic proteins was aided by periplasm prediction programs. Approximately 40% of all the proteins identified as periplasmic in the B. diazoefficiens genome were found expressed in the bacteroid form of the bacteria, indicating the periplasm is a metabolically active symbiotic space. The bacteroid periplasm possesses many fatty acid metabolic enzymes, which was in contrast to the bacteroid cytoplasm. Amino acid analysis of the periplasm revealed an abundance of phosphoserine, phosphoethanolamine, and glycine, which are metabolites of phospholipid metabolism. These results suggest the periplasm is a unique space and not a continuum with the peribacteroid space. A number of plant proteins were found in the periplasm fraction, which suggested contamination. However, antibodies to two of the identified plant proteins, histone H2A and lipoxygenase, yielded immunogold labeling that demonstrated the plant proteins were specifically targeted to the bacteroids. This suggests that the periplasm is an interkingdom symbiotic space containing proteins from both the bacteroid and the plant.

Serological characterization of black-pigmented Bacteroides endodontalis.

PubMed Central

van Winkelhoff, A J; Kippuw, N; de Graaff, J

1986-01-01

Serological studies on the black-pigmented Bacteroides species B. endodontalis revealed three serotypes based on capsular determinants. A common antigen (O-antigen) could be demonstrated after decapsulation. Weak cross-reactivity was found with B. asaccharolyticus, but not with B. gingivalis. Similarity between the serology of Enterobacteriaceae and black-pigmented Bacteroides spp. is discussed. PMID:3949388

Pathogenicity of facultative and obligate anaerobic bacteria in monoculture and combined with either Prevotella intermedia or Prevotella nigrescens.

PubMed

Siqueira, J F; Magalhães, F A; Lima, K C; de Uzeda, M

1998-12-01

The pathogenicity of obligate and facultative anaerobic bacteria commonly found in endodontic infections was tested using a mouse model. The capacity of inducing abscesses was evaluated seven days after subcutaneous injection of the bacteria in pure culture and in combinations with either Prevotella intermedia or Prevotella nigrescens. Nine of the fifteen bacterial strains tested were pathogenic in pure culture. No statistically significant differences were detected between these strains in pure culture and in mixtures with either P. intermedia or P. nigrescens. Synergism between the bacterial strains was only apparent when associating Porphyromonas endodontalis with P. intermedia or P. nigrescens. Histopathological examination of tissue sections from induced abscesses revealed an acute inflammatory reaction, dominated by polymorphonuclear leukocytes. Sections from the control group using sterile medium showed no evidence of inflammatory reaction.

[Studies on anaerobic infection in oro-maxillary region--rapid diagnosis by gas-liquid chromatography and antibiotic susceptibilities of anaerobic bacteria].

PubMed

Tanaka, J I

1989-08-01

Subject material for this study was pus collected from patients with purulent inflammation in the oro-maxillary region. Direct gas-liquid chromatography (GLC) analysis was made, bacterial isolation and identification were carried out, and comparisons were made with results from GLC analysis and anaerobic isolates in a PYG medium. In addition, antibiotic susceptibilities of anaerobic bacteria were examined. Results 1. Anaerobic bacteria were isolated from 85 of 100 cases of obstructive abscesses. Of the 85, 49 were cases of mixed infection involving both anaerobic and aerobic bacteria; and 64 cases were involved with more than 2 species of anaerobic bacteria. Of the 184 strains of anaerobic isolates, 53 were Bacteroides sp. and 51 were Peptostreptococcus sp. The 2 groups accounted for more than half of the isolates. 2. Group A, in which no VFA was detected, accounted for 17 out of 100 cases. Group B, in which acetic acid was detected, accounted for 20 cases; and Group C, in which butyric acid was detected, accounted for 20 cases; and Group D, in which iso-valeric acid was detected, accounted for 8 cases. Direct GLC analysis revealed iso-caproic and caproic acids in the 35 cases constituting Group E. 3. Whereas the percentage of anaerobic bacteria was 64.7% in Group A and 60% in Group B, significantly higher percentages were noted in Group C (95%), Group D (100%) and Group E (100%). The following species were isolated as major member in the groups; Group A--Streptococcus intermedius, Group B--Peptostreptococcus micros, Group C--Fusobacterium nucleatum, Group D--Bacteroides gingivalis, and Group E--Peptostreptococcus anaerobius. 4. In all cases, the sum of VFA produced in the PYG medium by anaerobic isolates was classified into Group A' to E'. Ratios of agreement between VFA as revealed by direct GLC and VFA as revealed by PYG.GLC were as follows: Group A-A'; 47.1%, Group B-B' and C-C'; 45%, Group D-D'; 87.5%, and Group E-E'; 62.9%. 5. In Group B, no propionic acid

Development of Vaccines to Prevent Wound Infections due to Anaerobic Bacteria

DTIC Science & Technology

1980-08-01

organism from neutrophil killing. A series of experiments were designed in the model of intraabdominal sepsis to determine the cellular mechanisms of...abscess, intraabdominal sepsis , and infections of the female genital tract (1). When optimal bacteriologic techniques are used, anaerobic bacteria can... sepsis or bacteremia. Members of the genus Bacteroides were second only to Escherichia coli as a cause of gram-negative septicemia in patients at the

CRISPR-Cas Systems in Bacteroides fragilis, an Important Pathobiont in the Human Gut Microbiome.

PubMed

Tajkarimi, Mehrdad; Wexler, Hannah M

2017-01-01

Background: While CRISPR-Cas systems have been identified in bacteria from a wide variety of ecological niches, there are no studies to describe CRISPR-Cas elements in Bacteroides species, the most prevalent anaerobic bacteria in the lower intestinal tract. Microbes of the genus Bacteroides make up ~25% of the total gut microbiome. Bacteroides fragilis comprises only 2% of the total Bacteroides in the gut, yet causes of >70% of Bacteroides infections. The factors causing it to transition from benign resident of the gut microbiome to virulent pathogen are not well understood, but a combination of horizontal gene transfer (HGT) of virulence genes and differential transcription of endogenous genes are clearly involved. The CRISPR-Cas system is a multi-functional system described in prokaryotes that may be involved in control both of HGT and of gene regulation. Results: Clustered regularly interspaced short palindromic repeats (CRISPR) elements in all strains of B. fragilis ( n = 109) with publically available genomes were identified. Three different CRISPR-Cas types, corresponding most closely to Type IB, Type IIIB, and Type IIC, were identified. Thirty-five strains had two CRISPR-Cas types, and three strains included all three CRISPR-Cas types in their respective genomes. The cas1 gene in the Type IIIB system encoded a reverse-transcriptase/Cas1 fusion protein rarely found in prokaryotes. We identified a short CRISPR (3 DR) with no associated cas genes present in most of the isolates; these CRISPRs were found immediately upstream of a hipA/hipB operon and we speculate that this element may be involved in regulation of this operon related to formation of persister cells during antimicrobial exposure. Also, blood isolates of B. fragilis did not have Type IIC CRISPR-Cas systems and had atypical Type IIIB CRISPR-Cas systems that were lacking adjacent cas genes. Conclusions: This is the first systematic report of CRISPR-Cas systems in a wide range of B. fragilis strains

CRISPR-Cas Systems in Bacteroides fragilis, an Important Pathobiont in the Human Gut Microbiome

PubMed Central

Tajkarimi, Mehrdad; Wexler, Hannah M.

2017-01-01

Background: While CRISPR-Cas systems have been identified in bacteria from a wide variety of ecological niches, there are no studies to describe CRISPR-Cas elements in Bacteroides species, the most prevalent anaerobic bacteria in the lower intestinal tract. Microbes of the genus Bacteroides make up ~25% of the total gut microbiome. Bacteroides fragilis comprises only 2% of the total Bacteroides in the gut, yet causes of >70% of Bacteroides infections. The factors causing it to transition from benign resident of the gut microbiome to virulent pathogen are not well understood, but a combination of horizontal gene transfer (HGT) of virulence genes and differential transcription of endogenous genes are clearly involved. The CRISPR-Cas system is a multi-functional system described in prokaryotes that may be involved in control both of HGT and of gene regulation. Results: Clustered regularly interspaced short palindromic repeats (CRISPR) elements in all strains of B. fragilis (n = 109) with publically available genomes were identified. Three different CRISPR-Cas types, corresponding most closely to Type IB, Type IIIB, and Type IIC, were identified. Thirty-five strains had two CRISPR-Cas types, and three strains included all three CRISPR-Cas types in their respective genomes. The cas1 gene in the Type IIIB system encoded a reverse-transcriptase/Cas1 fusion protein rarely found in prokaryotes. We identified a short CRISPR (3 DR) with no associated cas genes present in most of the isolates; these CRISPRs were found immediately upstream of a hipA/hipB operon and we speculate that this element may be involved in regulation of this operon related to formation of persister cells during antimicrobial exposure. Also, blood isolates of B. fragilis did not have Type IIC CRISPR-Cas systems and had atypical Type IIIB CRISPR-Cas systems that were lacking adjacent cas genes. Conclusions: This is the first systematic report of CRISPR-Cas systems in a wide range of B. fragilis strains

The frequency and some characteristics of anaerobic bacteria isolated from various forms of bovine mastitis.

PubMed

Greeff, A S; Du Preez, J H; De Beer, M

1983-03-01

The prevalence of strictly anaerobic bacteria in the secretions from untreated cases of mastitis in lactating dairy cows was investigated. The study involved 147 Friesland cows in 12 highveld herds. All herds yielded cows with anaerobic udder infections. No anaerobic bacteria were recovered from cows with normal quarters or those with latent aerobic infections. Only anaerobes were present in 10% of so-called 'aseptic' mastitis cases. A variety of anaerobic organisms was isolated concurrently with facultative bacteria from 5,3% and 58,8% of cases classified as subclinical and clinical respectively. Peptococcus spp. was associated with Corynebacterium pyogenes and Bacteroides spp. with Staphylococcus aureus and/or Streptococcus agalactiae in 80% anaerobic udder infections. Gram positive anaerobic species were mostly sensitive to penicillin-G but all the Gram negative rods were resistant. In addition, all B. fragilis strains produced beta-lactamase. The ability to produce heparinase was demonstrated in one strain of Peptococcus indolicus and a Peptostreptococcus sp.

Evaluation of the in vitro activity of levornidazole, its metabolites and comparators against clinical anaerobic bacteria.

PubMed

Hu, Jiali; Zhang, Jing; Wu, Shi; Zhu, Demei; Huang, Haihui; Chen, Yuancheng; Yang, Yang; Zhang, Yingyuan

2014-12-01

This study evaluated the in vitro anti-anaerobic activity and spectrum of levornidazole, its metabolites and comparators against 375 clinical isolates of anaerobic bacteria, including Gram-negative bacilli (181 strains), Gram-negative cocci (11 strains), Gram-positive bacilli (139 strains) and Gram-positive cocci (44 strains), covering 34 species. Minimum inhibitory concentrations (MICs) of levornidazole, its five metabolites and three comparators against these anaerobic isolates were determined by the agar dilution method. Minimum bactericidal concentrations (MBCs) of levornidazole and metronidazole were measured against 22 strains of Bacteroides fragilis. Levornidazole showed good activity against B. fragilis, other Bacteroides spp., Clostridium difficile, Clostridium perfringens and Peptostreptococcus magnus, evidenced by MIC90 values of 0.5, 1, 0.25, 2 and 1mg/L, respectively. The activity of levornidazole and the comparators was poor for Veillonella spp. Generally, levornidazole displayed activity similar to or slightly higher than that of metronidazole, ornidazole and dextrornidazole against anaerobic Gram-negative bacilli, Gram-positive bacilli and Gram-positive cocci, especially B. fragilis. Favourable anti-anaerobic activity was also seen with levornidazole metabolites M1 and M4 but not M2, M3 or M5. For the 22 clinical B. fragilis strains, MBC50 and MBC90 values of levornidazole were 2mg/L and 4mg/L, respectively. Both MBC50/MIC50 and MBC90/MIC90 ratios of levornidazole were 4, similar to those of metronidazole. Levornidazole is an important anti-anaerobic option in clinical settings in terms of its potent and broad-spectrum in vitro activity, bactericidal property, and the anti-anaerobic activity of its metabolites M1 and M4. Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Prevalence and characterization of enterotoxigenic Bacteroides fragilis and toxigenic Clostridium difficile in a Taipei emergency department.

PubMed

Ji, Dar-Der; Huang, I-Hsiu; Lai, Chao-Chih; Wu, Fang-Tzy; Jiang, Donald Dah-Shyong; Hsu, Bing-Mu; Lin, Wei-Chen

2017-02-01

Enterotoxigenic Bacteroides fragilis (ETBF) and toxin-encoding Clostridium difficile (TXCD) are associated with gastroenteritis. Routine anaerobic blood culture for recovery of these anaerobic pathogens is not used for the detection of their toxins, especially for toxin-variant TXCD. The aim of this study was to investigate the prevalence and risk factors of the genotypes of these anaerobes in patients with acute diarrheal illnesses. The data and samples of 513 patients with gastroenteritis were collected in a Taipei emergency department from March 1, 2006 to December 31, 2009. Nonenterotoxigenic B. fragilis (NTBF) and ETBF and the toxin genotypes of TXCD were detected by molecular methods. The prevalence rates of NTBF, ETBF, and TXCD infections were 33.14%, 1.56%, and 2.34%, respectively. ETBF infections often occurred in the elderly (average age = 67.13 years) and during the cold, dry winters. TXCD infections were widely distributed in age and often occurred in the warm, wet springs and summers. The symptoms of ETBF-infected patients were significantly more severe than those of NTBF-infected patients. This study identified and analyzed the prevalence, risk factors, and clinical presentations of these anaerobic infections. Future epidemiologic and clinical studies are needed to understand the role of ETBF and TXCD in human gastroenteritis. Copyright © 2015. Published by Elsevier B.V.

PCR detection and quantitation of predominant anaerobic bacteria in human and animal fecal samples.

PubMed Central

Wang, R F; Cao, W W; Cerniglia, C E

1996-01-01

PCR procedures based on 16S rRNA gene sequences specific for 12 anaerobic bacteria that predominate in the human intestinal tract were developed and used for quantitative detection of these species in human (adult and baby) feces and animal (rat, mouse, cat, dog, monkey, and rabbit) feces. Fusobacterium prausnitzii, Peptostreptococcus productus, and Clostridium clostridiiforme had high PCR titers (the maximum dilutions for positive PCR results ranged from 10(-3) to 10(-8)) in all of the human and animal fecal samples tested. Bacteroides thetaiotaomicron, Bacteroides vulgatus, and Eubacterium limosum also showed higher PCR titers (10(-2) to 10(-6)) in adult human feces. The other bacteria tested, including Escherichia coli, Bifidobacterium adolescentis, Bifidobacterium longum, Lactobacillus acidophilus, Eubacterium biforme, and Bacteroides distasonis, were either at low PCR titers (less than 10(-2)) or not detected by PCR. The reported PCR procedure including the fecal sample preparation method is simplified and rapid and eliminates the DNA isolation steps. PMID:8919784

Activity of a novel carbapenem, doripenem, against anaerobic pathogens.

PubMed

Goldstein, Ellie J C; Citron, Diane M

2009-04-01

Doripenem, a synthetic 1-beta-methyl carbapenem, has a broad-spectrum of activity against almost all species of anaerobic bacteria, including all Bacteroides fragilis group species, most with MIC(90) results at anaerobic intra-abdominal infections noted "noninferiority" of doripenem when compared with meropenem, but in vitro against the anaerobes, it was "more potent than meropenem, ertapenem, ... and similar to imipenem". Doripenem activity against anaerobes seems comparable with the other extant carbapenems. Although resistance among anaerobic bacteria to this agent is possible, it remains relatively rare.

Anaerobic bacteria in 118 patients with deep-space head and neck infections from the University Hospital of Maxillofacial Surgery, Sofia, Bulgaria.

PubMed

Boyanova, Lyudmila; Kolarov, Rossen; Gergova, Galina; Deliverska, Elitsa; Madjarov, Jivko; Marinov, Milen; Mitov, Ivan

2006-09-01

The aim of this study was to assess the incidence and susceptibility to antibacterial agents of anaerobic strains in 118 patients with head and neck abscesses (31) and cellulitis (87). Odontogenic infection was the most common identified source, occurring in 73 (77.7%) of 94 patients. The incidence of anaerobes in abscesses and cellulitis was 71 and 75.9%, respectively, and that in patients before (31 patients) and after (87) the start of empirical treatment was 80.6 and 72.4%, respectively. The detection rates of anaerobes in patients with odontogenic and other sources of infection were 82.2 and 71.4%, respectively. In total, 174 anaerobic strains were found. The predominant bacteria were Prevotella (49 strains), Fusobacterium species (22), Actinomyces spp. (21), anaerobic cocci (20) and Eubacterium spp. (18). Bacteroides fragilis strains were isolated from 7 (5.9%) specimens. The detection rate of Fusobacterium strains from non-treated patients (32.2%) was higher than that from treated patients (13.8%). Resistance rates to clindamycin and metronidazole of Gram-negative anaerobes were 5.4 and 2.5%, respectively, and those of Gram-positive species were 4.5 and 58.3%, respectively. One Prevotella strain was intermediately susceptible to ampicillin/sulbactam. In conclusion, the start of empirical treatment could influence the frequency or rate of isolation of Fusobacterium species. The involvement of the Bacteroides fragilis group in some head and neck infections should be considered.

Anaerobic infections in surgical wards: a two year study

PubMed Central

Ananth-Shenoy, Padmaja; Vishwanath, Shashidhar; Targain, Ryumzook; Shetty, Seema; Sunil-Rodrigues, Gabriel; Mukhopadhyay, Chiranjay; Chawla, Kiran

2016-01-01

Background and Objectives: Anaerobic bacteria are recognized as important pathogens in surgical infections. However, they are the most overlooked microorganisms by the clinic and the laboratory because of the tedious culture techniques with longer turn-around times. The study was aimed to analyze the frequency of anaerobic bacterial surgical infections and their predisposing factors. Materials and Methods: A retrospective study was conducted over a period of two years including patients with surgical infections. The specimens were processed by Gram staining, aerobic and anaerobic culture. The anaerobic bacteria were isolated using standard procedures. The predisposing factors and clinical presentation were studied in these patients. Results: A total of 261 specimens were received from patients with diverse infections from surgical wards. Ninety-one anaerobes were isolated from 64 (24.5%) surgical patients with a predominance of Gram-negative bacilli (37.4%). Anaerobic bacteria as monomicrobial isolates were seen in 21.9% isolates. Anaerobic bacterial isolation along with aerobic bacteria was seen in 71.9% of patients and polymicrobial anaerobic growth was detected in 6.3% of patients. Diabetes mellitus (28, 43.8%) was found to be the most frequent predisposing factor. Bacteroides fragilis group (20.9%) were the most frequent anaerobic Gram-negative bacilli followed by Prevotella spp. (12.1%). Peptostreptococcus anaerobius was the predominant anaerobic cocci isolated (14.3%). Necrotizing fascitis (34.4%) was the most common clinical presentation with anaerobic etiology followed by deep seated abscesses (23.4%). Conclusion: Anaerobic bacteria were isolated from a significant proportion of surgical infections. To avoid therapeutic failures, anaerobic bacteria in surgical infections need to be recognized by surgeons and laboratorians. PMID:27928485

Mechanism of quinolone resistance in anaerobic bacteria.

PubMed

Oh, H; Edlund, C

2003-06-01

Several recently developed quinolones have excellent activity against a broad range of aerobic and anaerobic bacteria and are thus potential drugs for the treatment of serious anaerobic and mixed infections. Resistance to quinolones is increasing worldwide, but is still relatively infrequent among anaerobes. Two main mechanisms, alteration of target enzymes (gyrase and topoisomerase IV) caused by chromosomal mutations in encoding genes, or reduced intracellular accumulation due to increased efflux of the drug, are associated with quinolone resistance. These mechanisms have also been found in anaerobic species. High-level resistance to the newer broad-spectrum quinolones often requires stepwise mutations in target genes. The increasing emergence of resistance among anaerobes may be a consequence of previous widespread use of quinolones, which may have enriched first-step mutants in the intestinal tract. Quinolone resistance in the Bacteroides fragilis group strains is strongly correlated with amino acid substitutions at positions 82 and 86 in GyrA (equivalent to positions 83 and 87 of Escherichia coli). Several studies have indicated that B. fragilis group strains possess efflux pump systems that actively expel quinolones, leading to resistance. DNA gyrase seems also to be the primary target for quinolones in Clostridium difficile, since amino acid substitutions in GyrA and GyrB have been detected in resistant strains. To what extent other mechanisms, such as mutational events in other target genes or alterations in outer-membrane proteins, contribute to resistance among anaerobes needs to be further investigated.

Comparison of the benzoyl-DL-arginine-naphthylamide (BANA) test, DNA probes, and immunological reagents for ability to detect anaerobic periodontal infections due to Porphyromonas gingivalis, Treponema denticola, and Bacteroides forsythus.

PubMed Central

Loesche, W J; Lopatin, D E; Giordano, J; Alcoforado, G; Hujoel, P

1992-01-01

Most forms of periodontal disease are associated with the presence or overgrowth of anaerobic species that could include Treponema denticola, Porphyromonas gingivalis, and Bacteroides forsythus among others. These three organisms are among the few cultivable plaque species that can hydrolyze the synthetic trypsin substrate benzoyl-DL-arginine-naphthylamide (BANA). In turn, BANA hydrolysis by the plaque can be associated with periodontal morbidity and with the presence of these three BANA-positive organisms in the plaque. In this investigation, the results of the BANA test, which simultaneously detects one or more of these organisms, were compared with the detection of these organisms by (i) highly specific antibodies to P. gingivalis, T. denticola, and B. forsythus; (ii) whole genomic DNA probes to P. gingivalis and T. denticola; and (iii) culturing or microscopic procedures. The BANA test, the DNA probes, and an enzyme-linked immunosorbent assay or an indirect immunofluorescence assay procedure exhibited high sensitivities, i.e., 90 ot 96%, and high accuracies, i.e., 83 to 92%, in their ability to detect combinations of these organisms in over 200 subgingival plaque samples taken from the most periodontally diseased sites in 67 patients. This indicated that if P. gingivalis, T. denticola, and B. forsythus are appropriate marker organisms for an anaerobic periodontal infection, then the three detection methods are equally accurate in their ability to diagnose this infection. The same statement could not be made for the culturing approach, where accuracies of 50 to 62% were observed. PMID:1311335

Taxonomy, virulence and epidemiology of black-pigmented Bacteroides species in relation to oral infections.

PubMed

van Steenbergen, T J; van Winkelhoff, A J; van der Velden, U; de Graaff, J

1989-01-01

Black-pigmented Bacteroides species are recognized as suspected pathogens of oral infections. Developments in the taxonomy of this group include description of a new asaccharolytic species, Bacteroides salivosus, and proposal for the reclassification of the asaccharolytic species into a separate genus, Porphyromonas. Studies on the pathogenicity and virulence of black-pigmented Bacteroides species have identified Bacteroides gingivalis as the most virulent species. B. gingivalis and Bacteroides intermedius have been associated with periodontal diseases; Bacteroides endodontalis is isolated specifically from infections in the oral cavity, and other black-pigmented Bacteroides species are recovered from oral mucous sites. DNA restriction endonuclease analysis was adapted for typing of B. gingivalis and B. intermedius.

[Activity of doripenem against anaerobic bacteria].

PubMed

Dubreuil, L; Neut, C; Mahieux, S; Muller-Serieys, C; Jean-Pierre, H; Marchandin, H; Soussy, C J; Miara, A

2011-04-01

This study examines the activity of doripenem, a new carbapenem compound compared with amoxicillin-clavulanic acid, piperacillin+tazobactam, imipenem, clindamycin and metronidazole against 316 anaerobes. Inoculum preparation and agar dilution method were performed according to the CLSI method for anaerobes (M11A7). At a concentration of 4μg/ml doripenem and imipenem (IMP) inhibited 122 (96 %) and 126 (99 %) strains of the Bacteroides fragilis group, respectively. In contrast, doripenem appeared more potent than IMP against Gram-positive anaerobes inhibiting at the same concentration of 4μg/ml 145/145 strains (100 %) versus 115/145 for IMP (79.3 %). Against 316 anaerobic strains, the carbapenem doripenem had an MIC(50) of 0.25μg/ml and an MIC(90) of 2μg/ml. Results were similar to those for imipenem (MIC(50) of 0.125μg/ml and MIC(90) of 4μg/ml). If we consider the resistant breakpoints of the two carbapenems as defined by EUCAST, the resistance rate for doripenem (MIC>4μg/ml) 1.6 % is similar to that of imipenem (MIC>8μg/ml) 1.3 %. Thus independently of the PK/PD parameters the two carbapenems demonstrated very close activity; doripenem was more potent on Gram-positive anaerobes and slightly less potent against Gram-negative anaerobes mainly the B. fragilis group. Further clinical studies are needed to assess its usefulness in patients. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

Xylan-regulated delivery of human keratinocyte growth factor-2 to the inflamed colon by the human anaerobic commensal bacterium Bacteroides ovatus.

PubMed

Hamady, Zaed Z R; Scott, Nigel; Farrar, Mark D; Lodge, J Peter A; Holland, Keith T; Whitehead, Terence; Carding, Simon R

2010-04-01

Human growth factors are potential therapeutic agents for various inflammatory disorders affecting the gastrointestinal tract. However, they are unstable when administered orally and systemic administration requires high doses increasing the risk of unwanted side effects. Live microorganism-based delivery systems can overcome these problems although they suffer from the inability to control heterologous protein production and there are concerns regarding biosafety and environmental contamination. To overcome these limitations we have developed a new live bacteria drug-delivery system using the human commensal gut bacterium Bacteroides ovatus engineered to secrete human growth factors in response to dietary xylan. The anaerobic nature of B ovatus provides an inherent biosafety feature. B ovatus strains expressing human keratinocyte growth factor-2, which plays a central role in intestinal epithelial homeostasis and repair (BO-KGF), were generated by homologous recombination and evaluated using the dextran sodium sulfate (DSS)-induced model of intestinal epithelial injury and colitis. In response to xylan BO-KGF produced biologically active KGF both in vitro and in vivo. In DSS treated mice administration of xylan and BO-KGF had a significant therapeutic effect in reducing weight loss, improving stool consistency, reducing rectal bleeding, accelerating healing of damaged epithelium, reducing inflammation and neutrophil infiltration, reducing expression of pro-inflammatory cytokines, and accelerating production of goblet cells. BO-KGF and xylan treatment also had a marked prophylactic effect limiting the development of inflammation and disruption of the epithelial barrier. This novel, diet-regulated, live bacterial drug delivery system may be applicable to treating various bowel disorders.

Plasmid analyses in clinical isolates of Bacteroides fragilis and other Bacteroides species.

PubMed Central

Wallace, B L; Bradley, J E; Rogolsky, M

1981-01-01

Plasmid analyses were performed on Bacteroides strains isolated from clinical specimens. Of 32 Bacteroides strains, 8 were found to contain plasmids. Seven of these eight strains were B. fragilis, and the other one was B. distasonis. Three of these eight strains harbored only a 3.0-megadalton plasmid. Two strains had only a 2.0-megadalton plasmid, and one had 2.0-, 3.0-megadalton plasmid. Of the remaining two strains, one had 2.0-, 3.0-, and 5.0-megadalton plasmids, and the other had 3.0- and 5.0-megadalton plasmids. Beta-Lactamase was produced by 93% of the clinical isolates. Seven of the eight plasmid-carrying strains were cadmium resistant, five were zinc resistant, four were mercury resistant, and two expressed a brick-red fluorescence under ultraviolet light. None of these traits could be associated with a plasmid after performing either curing experiments or genetic transfer experiments by cell-to-cell contact. Images PMID:6974737

Xylan-regulated Delivery of Human Keratinocyte Growth Factor-2 to the Inflamed Colon by the Human Anaerobic Commensal Bacterium Bacteroides ovatus

USDA-ARS?s Scientific Manuscript database

The use of genetically modified bacteria to deliver biologically active molecules directly to the gut has become an increasingly attractive area of investigation. The challenge of regulation of production of the therapeutic molecule and colonization of the bowel led us to investigate Bacteroides ov...

Cupriavidus taiwanensis bacteroids in Mimosa pudica Indeterminate nodules are not terminally differentiated.

PubMed

Marchetti, Marta; Catrice, Olivier; Batut, Jacques; Masson-Boivin, Catherine

2011-03-01

The beta-rhizobium Cupriavidus taiwanensis forms indeterminate nodules on Mimosa pudica. C. taiwanensis bacteroids resemble free-living bacteria in terms of genomic DNA content, cell size, membrane permeability, and viability, in contrast to bacteroids in indeterminate nodules of the galegoid clade. Bacteroid differentiation is thus unrelated to nodule ontogeny.

In-vitro activity of solithromycin against anaerobic bacteria from the normal intestinal microbiota.

PubMed

Weintraub, Andrej; Rashid, Mamun-Ur; Nord, Carl Erik

2016-12-01

Solithromycin is a novel fluoroketolide with high activity against bacteria associated with community-acquired respiratory tract infections as well as gonorrhea. However, data on the activity of solithromycin against anaerobic bacteria from the normal intestinal microbiota are scarce. In this study, 1024 Gram-positive and Gram-negative anaerobic isolates from the normal intestinal microbiota were analyzed for in-vitro susceptibility against solithromycin and compared to azithromycin, amoxicillin/clavulanic acid, ceftriaxone, metronidazole and levofloxacin by determining the minimum inhibitory concentration (MIC). Solithromycin was active against Bifidobacteria (MIC 50 , 0.008 mg/L) and Lactobacilli (MIC 50 , 0.008 mg/L). The MIC 50 for Clostridia, Bacteroides, Prevotella and Veillonella were 0.5, 0.5, 0.125 and 0.016 mg/L, respectively. Gram-positive anaerobes were more susceptible to solithromycin as compared to the other antimicrobials tested. The activity of solithromycin against Gram-negative anaerobes was equal or higher as compared to other tested agents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Further characterization of Bacteroides endodontalis, an asaccharolytic black-pigmented Bacteroides species from the oral S cavity.

PubMed Central

van Winkelhoff, A J; van Steenbergen, T J; Kippuw, N; De Graaff, J

1985-01-01

In this study, the isolation, characterization, and identification of Bacteroides endodontalis is described. It was found that this asaccharolytic black-pigmented Bacteroides species is associated with infected dental root canals and oral submucous abscesses. B. endodontalis could be differentiated from B. gingivalis by a negative direct hemagglutination test and the absence of trypsin and N-acetyl-beta-glucosamidase. B. endodontalis could be differentiated from B. asaccharolyticus by the absence of alpha-fucosidase, its inability to grow in an atmosphere of 95% N2-5% H2, and a growth requirement for menadione. Immune serum raised against B. endodontalis strain HG 370T agglutinated only B. endodontalis cells. Precautions for the isolation of B. endodontalis are discussed. PMID:3926818

Clinical evaluation of the Vitek ANI card for identification of anaerobic bacteria.

PubMed Central

Schreckenberger, P C; Celig, D M; Janda, W M

1988-01-01

An evaluation of the Vitek Anaerobe Identification (ANI) card was performed with 341 bacterial isolates, including 313 clinical isolates and 28 stock strains of anaerobic microorganisms. Identifications obtained with the ANI card were compared with those determined by conventional methods. The card identified 73.2% of 149 anaerobic gram-negative bacilli, 63.6% of 44 Clostridium spp., 65.8% of 38 anaerobic nonsporeforming gram-positive bacilli, and 69.1% of 110 anaerobic cocci, with no further testing required. When genus-level identifications were included, 83.9% of the anaerobic gram-negative bacilli, 70.5% of Clostridium spp., 73.7% of the anaerobic nonsporeforming gram-positive bacilli, and 73.6% of the anaerobic cocci were identified. Nineteen isolates (5.6%) produced identifications of good confidence but marginal separation or questionable biotype, in which the correct identification was listed with one or two other possible choices and extra tests were required and suggested. A total of 28 (8.2%) were not identified and 29 isolates (8.5%) were misidentified by the ANI card. Among the commonly isolated clinically significant anaerobes, the ANI card identified 100% of 55 Bacteroides fragilis and 100% of 8 Clostridium perfringens. Use of supplemental tests and expansion of the data base to include additional strains of organisms that are difficult to separate even with conventional methods may improve the accuracy of the ANI card as a method for identification of anaerobic bacteria in the clinical laboratory. PMID:3343321

Cupriavidus taiwanensis Bacteroids in Mimosa pudica Indeterminate Nodules Are Not Terminally Differentiated ▿

PubMed Central

Marchetti, Marta; Catrice, Olivier; Batut, Jacques; Masson-Boivin, Catherine

2011-01-01

The beta-rhizobium Cupriavidus taiwanensis forms indeterminate nodules on Mimosa pudica. C. taiwanensis bacteroids resemble free-living bacteria in terms of genomic DNA content, cell size, membrane permeability, and viability, in contrast to bacteroids in indeterminate nodules of the galegoid clade. Bacteroid differentiation is thus unrelated to nodule ontogeny. PMID:21257807

Development and evaluation of the quick anaero-system-a new disposable anaerobic culture system.

PubMed

Yang, Nam Woong; Kim, Jin Man; Choi, Gwang Ju; Jang, Sook Jin

2010-04-01

We developed a new disposable anaerobic culture system, namely, the Quick anaero-system, for easy culturing of obligate anaerobes. Our system consists of 3 components: 1) new disposable anaerobic gas pack, 2) disposable culture-envelope and sealer, and 3) reusable stainless plate rack with mesh containing 10 g of palladium catalyst pellets. To evaluate the efficiency of our system, we used 12 anaerobic bacteria. We prepared 2 sets of ten-fold serial dilutions of the 12 anaerobes, and inoculated these samples on Luria-Bertani (LB) broth and LB blood agar plate (LB-BAP) (BD Diagnostic Systems, USA). Each set was incubated in the Quick anaero-system (DAS Tech, Korea) and BBL GasPak jar with BD GasPak EZ Anaerobe Container System (BD Diagnostic Systems) at 35-37 degrees C for 48 hr. The minimal inoculum size showing visible growth of 12 anaerobes when incubated in both the systems was compared. The minimal inoculum size showing visible growth for 2 out of the 12 anaerobes in the LB broth and 9 out of the 12 anaerobes on LB-BAP was lower for the Quick anaero-system than in the BD GasPak EZ Anaerobe Container System. The mean time (+/-SD) required to achieve absolute anaerobic conditions of the Quick anaero-system was 17 min and 56 sec (+/-3 min and 25 sec). The Quick anaero-system is a simple and effective method of culturing obligate anaerobes, and its performance is superior to that of the BD GasPak EZ Anaerobe Container System.

Evaluation of Fluoretec-M for detection of oral strains of Bacteroides asaccharolyticus and Bacteroides melaninogenicus.

PubMed Central

Mouton, C; Hammond, P; Slots, J; Genco, R J

1980-01-01

Fluoretec-M is a polyvalent conjugate used in direct fluorescent-antibody staining for identification of the Bacteroides asaccharolyticus-Bacteroides melaninogenicus group. The Fluoretec-M reagent detected all oral and nonoral test strains of B. melaninogaenicus subsp. intermedius, all test strains of B. melaninogenicus subsp. melaninogenicus, and the nonoral strains of B. asaccharolyticus. However, the Fluoretec-M polyvalent reagent and the monovalent conjugates which constitute Fluoretec-M did not detect the oral strains B. asaccharolyticus. The use of Fluoretec-M can therefore generate false-negative results in studies of specimens from oral cavity and from nonoral sites in which an infection with B. asacacharolyticus of oral origin may have taken place. It is suggested that antibodies reactive with the oral antigenic type of B. asaccharolyticus be included in the preparative procedure of the Fluoretec-M reagent. PMID:6107305

A study on Nim expression in Bacteroides fragilis

PubMed Central

Leitsch, David; Sóki, József; Kolarich, Daniel; Urbán, Edit; Nagy, Elisabeth

2016-01-01

Summary Members of the genus Bacteroides, mainly Bacteroides fragilis, can cause severe disease in man, especially after intestinal perforation in the course of abdominal surgery. Treatment is based on a small number of antibiotics, including metronidazole which has proved to be highly reliable throughout the last 40 to 50 years. Nevertheless, metronidazole resistance does occur in Bacteroides and has been mainly attributed to Nim proteins, a class of proteins with suggested nitroreductase function. Despite the potentially high importance of Nim proteins for human health, information on the expression of nim genes in Bacteroides fragilis is still lacking. It was the aim of this study to demonstrate expression of nim genes in B. fragilis at the protein level and, further, to correlate the level of Nim levels with the level of metronidazole resistance. By application of two-dimensional gel electrophoresis, Nim proteins could be readily identified in nim-positive strains but their levels were not elevated to a relevant extent after induction of resistance to high doses of metronidazole. Thus, the presented data do not provide evidence for Nim proteins acting as nitroreductases using metronidazole as a substrate because no correlation of Nim levels and level of resistance could be observed. Further, no evidence was found that Nim proteins protect B. fragilis from metronidazole by sequestering activated metronidazole. PMID:24448511

Fish meal extract bile esculin agar (FMBE) a selective medium for Bacteroides fragilis group.

PubMed

Beena, V K; Rao, S; Kotian, M; Shivananda, P G

1997-07-01

Fish meal extract bile esculin agar (FMBE) is prepared using Fish meal extract concentrate as the basal substance, for the selective isolation and presumptive identification of B.fragilis group. The efficiency of the medium was evaluated by growing stock cultures of B.fragilis groups as well as inoculating clinical specimens and comparing the results with Bacteroides bile esculin agar (BBE). All the 87 stock cultures of B.fragilis grew on FMBE and BBE. No other anaerobes tested grew on the medium. However 7 out of 65 neomycin resistant aerobes grew on the FMBE. From the 100 clinical samples, 62 strains of B. Fragilis group were recovered on FMBE and BBE, and 53 strains on supplemented BHIBA. The cost effectiveness, selectivity and the ability to detect esculin hydrolysis will enable FMBE as a suitable medium as comparable to that of BBE, if not superior.

Peritoneal dialysis peritonitis by anaerobic pathogens: a retrospective case series

PubMed Central

2013-01-01

Background Bacterial infections account for most peritoneal dialysis (PD)-associated peritonitis episodes. However, anaerobic PD peritonitis is extremely rare and intuitively associated with intra-abdominal lesions. In this study, we examined the clinical characteristics of PD patients who developed anaerobic peritonitis. Methods We retrospectively identified all anaerobic PD peritonitis episodes from a prospectively collected PD registry at a single center between 1990 and 2010. Only patients receiving more than 3 months of PD were enrolled. We analyzed clinical features as well as outcomes of anaerobic PD peritonitis patients. Results Among 6 patients, 10 episodes of PD-associated peritonitis were caused by anaerobic pathogens (1.59% of all peritonitis episodes during study the period), in which the cultures from 5 episodes had mixed growth. Bacteroides fragilis was the most common species identified (4 isolates). Only 3 episodes were associated with gastrointestinal lesions, and 4 episodes were related to a break in sterility during exchange procedures. All anaerobic pathogens were susceptible to clindamycin and metronidazole, but penicillin resistance was noted in 4 isolates. Ampicillin/sulbactam resistance was found in 2 isolates. In 5 episodes, a primary response was achieved using the first-generation cephalosporin and ceftazidime or aminoglycoside. In 3 episodes, the first-generation cephalosporin was replaced with aminoglycosides. Tenckhoff catheter removal was necessary in 2 episodes. Only one episode ended with mortality (due to a perforated bowel). Conclusion Anaerobic PD-associated peritonitis might be predominantly caused by contamination, rather than intra-abdominal events. Half of anaerobic PD-associated peritonitis episodes had polymicrobial growth. The overall outcome of anaerobic peritonitis is fair, with a high catheter survival rate. PMID:23705895

Anaerobic bacteria colonizing the lower airways in lung cancer patients.

PubMed

Rybojad, Pawel; Los, Renata; Sawicki, Marek; Tabarkiewicz, Jacek; Malm, Anna

2011-01-01

Anaerobes comprise most of the endogenous oropharyngeal microflora, and can cause infections of airways in lung cancer patients who are at high risk for respiratory tract infections. The aim of this study was to determine the frequency and species diversity of anaerobes in specimens from the lower airways of lung cancer patients. Sensitivity of the isolates to conventional antimicrobial agents used in anaerobe therapy was assessed. Respiratory secretions obtained by bronchoscopy from 30 lung cancer patients were cultured onto Wilkins-Chalgren agar in anaerobic conditions at 37°C for 72-96 hours. The isolates were identified using microtest Api 20A. The minimal inhibitory concentrations for penicillin G, amoxicillin/clavulanate, piperacillin/tazobactam, cefoxitin, imipenem, clindamycin, and metronidazole were determined by E-test. A total of 47 isolates of anaerobic bacteria were detected in 22 (73.3%) specimens. More than one species of anaerobe was found in 16 (53.3%) samples. The most frequently isolated were Actinomyces spp. and Peptostreptococcus spp., followed by Eubacterium lentum, Veillonella parvula, Prevotella spp., Bacteroides spp., Lactobacillus jensenii. Among antibiotics used in the study amoxicillin/clavulanate and imipenem were the most active in vitro (0% and 2% resistant strains, respectively). The highest resistance rate was found for penicillin G and metronidazole (36% and 38% resistant strains, respectively). The results obtained confirm the need to conduct analyses of anaerobic microflora colonizing the lower respiratory tract in patients with lung cancer to monitor potential etiologic factors of airways infections, as well as to propose efficient, empirical therapy.

In vitro activity of FK037, a new parenteral cephalosporin, against anaerobic bacteria.

PubMed Central

Kato, N; Kato, H; Tanaka, Y; Bando, K; Watanabe, K; Ueno, K

1993-01-01

The activity of FK037, a new parenteral cephalosporin, was compared with those of cefpirome, ceftazidime, and flomoxef against 322 recent clinical isolates of anaerobic bacteria. A fastidious facultative anaerobe, Gardnerella vaginalis, was also studied. FK037 inhibited 90% of isolates of Peptostreptococcus anaerobius, Peptostreptococcus asaccharolyticus, Clostridium perfringens, Mobiluncus spp., G. vaginalis, and Porphyromonas gingivalis at < or = 0.78 micrograms/ml. The MICs of FK037 for 50 and 90% of Bacteroides fragilis isolates were 25 and > 200 micrograms/ml, respectively; the activity of FK037 was comparable to those of cefpirome and ceftazidime but lower than that of flomoxef. The activity of FK037 against Fusobacterium nucleatum, Fusobacterium varium, and Bilophila wadsworthia decreased when inoculum size was increased from 10(6) to 10(8) CFU/ml. Little influence of inoculum size on the activity of FK037 was observed for other isolates tested. Medium pH affected the activity of FK037 against F. varium (MICs at pHs 5 and 7, 3.13 and 100 micrograms/ml, respectively) and Bacteroides gracilis (MICs at pHs 5 and 7, 12.5 and 1.56 micrograms/ml, respectively) but not against other organisms tested. FK037 was less resistant than flomoxef to hydrolysis by beta-lactamase group 2e derived from B. fragilis GAI 0558 and GAI 10150. PMID:8517721

Molecular Investigations of Bacteroides as Microbial Source Tracking Tools in Southeast Louisiana Watersheds

NASA Astrophysics Data System (ADS)

Schulz, C. J.; Childers, G. W.; Engel, A. S.

2006-12-01

Microbial Source Tracking (MST) is a developing field that is gaining increased attention. MST refers to a host of techniques that discriminates among the origins of fecal material found in natural waters from different sources (e.g. human, livestock, and wildlife) by using microbial indicator species with specificity to only certain host organisms. The development of species-specific molecular markers would allow for better evaluation of public health risks and tracking of nutrient sources impacting a watershed. Although several MST methods have been reported with varying levels of success, few offer general applicability for natural waters due to spatial and temporal constraints associated with these methods. One group of molecular MST markers that show promise for broad environmental applications are molecular 16S rDNA probes for Bacteroides. This method is based on 16S rDNA detection directly from environmental samples without the need for a preliminary cultivation step. In this study we have expanded previous sampling efforts to compile a database of over 1000 partial 16S rRNA Bacteroides genes retrieved from the fecal material of 15 different host species (human, cat, dog, pig, kangaroo). To characterize survival of Bacteroides outside of the host, survival time of the Bacteroides marker was compared to that of E.coli under varying natural environmental conditions (temperature and salinity). Bacteroides displayed a survival curve with shouldering and tailing similar to that of E.coli, but log reduction times differed with treatment. In summary, MST marker stability was identified within host species and the overall Bacteroides community structure correlated to host diet, suggesting that detection of a Bacteroides community could confidently identify fecal contamination point sources. Natural water samples from southeast Louisiana were collected for MST including the Tangipahoa River watershed where the source of fecal contamination has been hotly debated. The

Spirochaeta americana sp. nov.: A New Haloalkaliphilic, Obligately Anaerobic Spirochete Isolated from Soda Mono Lake, California

NASA Technical Reports Server (NTRS)

Hoover, Richard B.; Pikuta, Elena V.; Marsic, Damien; Whitman, William B.; Tang, Jane; Krader, Paul; Six, N. Frank (Technical Monitor)

2002-01-01

A novel obligately anaerobic, mesophilic, haloalkaliphilic spirochete, strain ASpG1, was isolated from sediments of the alkaline, hypersaline Mono Lake in California, U.S.A. The gram-negative cells are motile and spirochete-shaped with sizes of 0.22 x 10-15 micron. Growth was observed over the temperature range of 10 C to 44 C (optimum 37 C), NaCl concentration range of greater than 1 - 12 % (wt/vol) (optimum 3%), and pH range 7.5 - 10.5 (optimum pH 9.5). The novel isolate is strictly alkaliphilic, requires high concentrations of carbonate in the medium, and is capable of utilizing D-glucose, fructose, maltose, sucrose, starch, and D-mannitol. Main end products of glucose fermentation are: H2, acetate, ethanol, and formate. Strain AspG1 is resistant to kanamycin, but sensitive to chloramphenicol, gentamycin and tetracycline. The G+C content of its DNA is 58.5 mol%. On the basis of its physiological and molecular properties, the isolate appears to be a novel species among the genus Spirochaeta; and the name Spirochaeta americana sp. nov., is proposed for the taxon (type strain ASpG1(sup T) = ATCC BAA_392(sup T) = DSMZ 14872(sup T)).

Potential Application of Anaerobic Extremophiles for Hydrogen Production

NASA Technical Reports Server (NTRS)

Pikuta, Elena V.; Hoover, Richard B.

2004-01-01

During substrate fermentation many anaerobes produce the hydrogen as a waste product, which often regulates the growth of the cultures as an inhibitor. In nature the hydrogen is usually removed from the ecosystem due to its physical properties or by consumption of hydrogen by secondary anaerobes, which sometimes behave as competitors for electron donors as is seen in the classical example in anaerobic microbial communities via the interaction between methanogens and sulfate- or sulfur- reducers. It was demonstrated previously on mixed cultures of anaerobes at neutral pH that bacterial hydrogen production could provide an alternative energy source. But at neutral pH the original cultures can easily be contaminated by methanogens, a most unpleasant side effect of these conditions is the development of pathogenic bacteria. In both cases the rate of hydrogen production was dramatically decreased since some part of the hydrogen was transformed to methane, and the cultivation of human pathogens on a global scale is very dangerous. In our laboratory, experiments with obligately alkaliphilic bacteria that excrete hydrogen as the end metabolic product were performed at different temperature regimes. Mesophilic and moderately thermophilic bacterial cultures have been studied and compared for the most effective hydrogen production. For high-mineralized media with pH 9.5-10.0 not many methanogens are known to exist. Furthermore, the development of pathogenic contaminant microorganisms is virtually impossible: carbonate-saturated solutions are used as antiseptics in medicine. Therefore the cultivation of alkaliphilic hydrogen producing bacteria could be considered as most safe process for global Scale industry in future. Here we present experimental data on the rates of hydrogen productivity for mesophilic, alkaliphilic, obligately anaerobic bacterium Spirocheta americana ASpG1 and moderately thermophilic, alkaliphilic, facultative anaerobe Anoxybacillus pushchinoensis K1 and

Activity of semisynthetic penicillins and synergism with mecillinam against Bacteroides species.

PubMed Central

Trestman, I; Kaye, D; Levison, M E

1979-01-01

The minimal inhibitory concentrations (MIC) of six penicillins (ampicillin, carbenicillin, ticarcillin, piperacillin, mezlocillin, and Bay k 4999) against 29 clinical isolates of Bacteriodes spp. (including Bacteroides fragilis, Bacteroides thetaiotaomicron, and Bacteroides vulgatus) were determined by an agar dilution method. Bay k 4999 was most active, followed in descending order by ampicillin, piperacillin, mezlocillin, ticarcillin, and carbenicillin. Mecillinam, a 6 beta-amidino-penicillanic acid, inhibited no strains at 50 micrograms/ml, but when compared with ampicillin, a fourfold or greater increase in MIC for ampicillin (antagonism) was noted in 3 of 29 strains, with no effect on MIC for 26 strains, whereas when combined with carbenicillin, a fourfold or greater decrease in MIC for both antibiotics (synergism) was noted in 12 strains, 4 of which had an MIC of greater than or equal to 250 micrograms/ml for carbenicillin alone. These studies demonstrate the increased activity of some newer semisynthetic penicillins and the potential synergy obtained with mecillinam and carbenicillin against Bacteroides sp. PMID:228593

Use of synthetic oligonucleotide DNA probes for the identification of Bacteroides gingivalis.

PubMed Central

Moncla, B J; Braham, P; Dix, K; Watanabe, S; Schwartz, D

1990-01-01

Six different oligonucleotide probes complementary to the hypervariable regions of 16S rRNA of Bacteroides gingivalis were tested for specificity and sensitivity against 77 field strains of B. gingivalis and 105 strains of 12 other Bacteroides species. The data demonstrated that these probes were very specific (range, 0.85 to 1.00) and sensitive (1.00). Some limited cross-reactions with other Bacteroides species were observed. Four of these probes should be useful for rapid detection and identification of B. gingivalis. Images PMID:1690217

MALDI-TOF MS identification of anaerobic bacteria: assessment of pre-analytical variables and specimen preparation techniques.

PubMed

Hsu, Yen-Michael S; Burnham, Carey-Ann D

2014-06-01

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has emerged as a tool for identifying clinically relevant anaerobes. We evaluated the analytical performance characteristics of the Bruker Microflex with Biotyper 3.0 software system for identification of anaerobes and examined the impact of direct formic acid (FA) treatment and other pre-analytical factors on MALDI-TOF MS performance. A collection of 101 anaerobic bacteria were evaluated, including Clostridium spp., Propionibacterium spp., Fusobacterium spp., Bacteroides spp., and other anaerobic bacterial of clinical relevance. The results of our study indicate that an on-target extraction with 100% FA improves the rate of accurate identification without introducing misidentification (P<0.05). In addition, we modify the reporting cutoffs for the Biotyper "score" yielding acceptable identification. We found that a score of ≥1.700 can maximize the rate of identification. Of interest, MALDI-TOF MS can correctly identify anaerobes grown in suboptimal conditions, such as on selective culture media and following oxygen exposure. In conclusion, we report on a number of simple and cost-effective pre- and post-analytical modifications could enhance MALDI-TOF MS identification for anaerobic bacteria. Copyright © 2014 Elsevier Inc. All rights reserved.

Gardnerella vaginalis and anaerobic bacteria in the etiology of bacterial (nonspecific) vaginosis.

PubMed

Spiegel, C A; Davick, P; Totten, P A; Chen, K C; Eschenbach, D A; Amsel, R; Holmes, K K

1983-01-01

G. vaginalis was originally described as the etiologic agent of bacterial vaginosis (nonspecific vaginitis) because it was recovered only from women with signs and symptoms of "bacterial vaginitis" and not from normal controls. Recent data have shown that G. vaginalis is present in normal women but at concentrations lower than the limit of sensitivity of the media formerly used. Detection of low concentrations of G. vaginalis in normal controls has been made possible by development of a selective and differential medium (HBT). Anaerobically performed studies of the vaginal flora have indicated that while lactobacilli predominate in the normal vagina with or without G. vaginalis, anaerobic bacteria including Bacteroides spp., Peptococcus spp., Eubacterium spp. and curved rods as well as G. vaginalis predominate in bacterial vaginosis. Anaerobic bacteria and G. vaginalis are decreased after appropriate therapy. After treatment with metronidazole, lactobacilli again predominate. Lactobacilli are less prevalent after treatment with ampicillin or amoxicillin. These data suggest that as in infections at other mucous membrane sites, bacterial vaginosis is a mixed infection involving a finite number of facultative and anaerobic species. The data also suggest an important role for facultative lactobacilli.

Multicenter Study of Antimicrobial Susceptibility of Anaerobic Bacteria in Korea in 2012

PubMed Central

Lee, Yangsoon; Park, Yeon-Joon; Kim, Mi-Na; Uh, Young; Kim, Myung Sook

2015-01-01

Background Periodic monitoring of regional or institutional resistance trends of clinically important anaerobic bacteria is recommended, because the resistance of anaerobic pathogens to antimicrobial drugs and inappropriate therapy are associated with poor clinical outcomes. There has been no multicenter study of clinical anaerobic isolates in Korea. We aimed to determine the antimicrobial resistance patterns of clinically important anaerobes at multiple centers in Korea. Methods A total of 268 non-duplicated clinical isolates of anaerobic bacteria were collected from four large medical centers in Korea in 2012. Antimicrobial susceptibility was tested by the agar dilution method according to the CLSI guidelines. The following antimicrobials were tested: piperacillin, piperacillin-tazobactam, cefoxitin, cefotetan, imipenem, meropenem, clindamycin, moxifloxacin, chloramphenicol, metronidazole, and tigecycline. Results Organisms of the Bacteroides fragilis group were highly susceptible to piperacillin-tazobactam, imipenem, and meropenem, as their resistance rates to these three antimicrobials were lower than 6%. For B. fragilis group isolates and anaerobic gram-positive cocci, the resistance rates to moxifloxacin were 12-25% and 11-13%, respectively. Among B. fragilis group organisms, the resistance rates to tigecycline were 16-17%. Two isolates of Finegoldia magna were non-susceptible to chloramphenicol (minimum inhibitory concentrations of 16-32 mg/L). Resistance patterns were different among the different hospitals. Conclusions Piperacillin-tazobactam, cefoxitin, and carbapemems are highly active β-lactam agents against most of the anaerobes. The resistance rates to moxifloxacin and tigecycline are slightly higher than those in the previous study. PMID:26206683

Anaerobic culture to detect periodontal and caries pathogens

PubMed Central

Tanner, Anne C. R.

2014-01-01

Background Anaerobic culture has been critical in our understanding of the oral microbiotas. Highlight Studies in advanced periodontitis in the 1970’s revealed microbial complexes that associated with different clinical presentations. Taxonomy studies identified species newly-observed in periodontitis as Aggregatibacter (Actinobacillus) actinomycetemcomitans, Campylobacter (Wolinella) rectus and other Campylobacter species, and Tannerella (Bacteroides) forsythia. Anaerobic culture of initial periodontitis showed overlap in the microbiota with gingivitis, and added Selenomonas noxia and Filifactor alocis as putative periodontal pathogens. Porphyromonas gingivalis and T. forsythia were found to be associated with initial periodontitis in adults. The dominant microbiota of dental caries differs from that of periodontitis. The major cariogenic species are acidogenic and acid tolerant species particularly Streptococcus mutans, and Lactobacillus and Bifidobacterium species. Anaerobic culture of severe early childhood caries revealed a widely diverse microbiota, comparable to that observed using cloning and sequencing. The PCR-based cloning approach, however, underestimated Actinobacteria compared with culture. Only a subset of the caries-associated microbiota was acid tolerant, with different segments of the microbiota cultured on blood agar compared to a low pH acid agar. While the major caries-associated species was S. mutans, a new species, Scardovia wiggsiae, was significantly associated with early childhood caries. Higher counts of S. wiggsiae were also observed in initial white spot carious lesions in adolescents. Conclusion In periodontitis and dental caries, anaerobic culture studies of advanced disease provided a comprehensive analysis of the microbiota of these infections. Anaerobic culture highlighted the limitation of PCR with standard primers that underestimate detection of Actinobacteria. PMID:25678835

Aerobic and anaerobic bacteria in tonsils of children with recurrent tonsillitis.

PubMed

Brook, I; Yocum, P; Friedman, E M

1981-01-01

Tonsils were obtained from 50 children suffering from recurrent tonsillitis. Patients' ages ranged from 2.5 to 17 years (mean 6 years); 29 were males and 21 females. The tonsils were sectioned in half after heat searing of the surface and the core material was cultured for aerobic and anaerobic microorganisms. Mixed aerobic and anaerobic flora was obtained in all patients, yielding an average of 7.8 isolates (4.1 anaerobes and 3.7 aerobes) per specimen. There were 207 anaerobes isolated. The predominant isolates were 101 Bacteroides sp (including 10 B fragilis group, and 47 B melaninogenicus group), 29 Fusobacterium sp, 34 Gram-positive anaerobic cocci (25 Peptococcus sp and 9 Peptostreptococcus sp) and 16 Veillonella sp. There were 185 aerobic isolates. The predominant isolates were 41 alpha-hemolytic streptococci, 24 Staphylococcus aureus, 19 beta-hemolytic streptococci (11 group A, 4 group B, and 2 each group C and F), 14 Haemophilus sp (including 12 H influenzae type B) and 5 H parainfluenzae. Beta-lactamase production was noted in 56 isolates recovered from 37 tonsils. These were all isolates of S aureus (24) and B fragilis (10), 15 of 47 B melaninogenicus (32%), 5 of the 12 B oralis (42%), and 2 of 12 H influenzae type B (17%). Our findings indicate the polymicrobial aerobic and anaerobic nature of deep tonsillar flora in children with recurrent tonsillitis, and demonstrate the presence of many beta-lactamase-producing organisms in 74% of the patients.

Live Faecalibacterium prausnitzii induces greater TLR2 and TLR2/6 activation than the dead bacterium in an apical anaerobic co-culture system.

PubMed

Maier, Eva; Anderson, Rachel C; Altermann, Eric; Roy, Nicole C

2018-02-01

Inappropriate activation of intestinal innate immune receptors, such as toll-like receptors (TLRs), by pathogenic bacteria is linked to chronic inflammation. In contrast, a "tonic" level of TLR activation by commensal bacteria is required for intestinal homeostasis. A technical challenge when studying this activation in vitro is the co-culturing of oxygen-requiring mammalian cells with obligate anaerobic commensal bacteria. To overcome this, we used a novel apical anaerobic co-culture system to successfully adapt a TLR activation assay to be conducted in conditions optimised for both cell types. Live Faecalibacterium prausnitzii, an abundant obligate anaerobe of the colonic microbiota, induced higher TLR2 and TLR2/6 activation than the dead bacterium. This enhanced TLR induction by live F. prausnitzii, which until now has not previously been described, may contribute to maintenance of gastrointestinal homeostasis. This highlights the importance of using physiologically relevant co-culture systems to decipher the mechanisms of action of live obligate anaerobes. © 2017 John Wiley & Sons Ltd.

In Vitro Antimicrobial Activity of Razupenem (SMP-601, PTZ601) against Anaerobic Bacteria▿

PubMed Central

Tran, Chau Minh; Tanaka, Kaori; Yamagishi, Yuka; Goto, Takatsugu; Mikamo, Hiroshige; Watanabe, Kunitomo

2011-01-01

We evaluated the in vitro antianaerobic activity of razupenem (SMP-601, PTZ601), a new parenterally administered carbapenem, against 70 reference strains and 323 clinical isolates. Razupenem exhibited broad-spectrum activity against anaerobes, inhibiting most of the reference strains when used at a concentration of ≤1 μg/ml. Furthermore, it exhibited strong activity, comparable to those of other carbapenems (meropenem and doripenem), against clinically isolated non-fragilis Bacteroides spp. (MIC90s of 2 μg/ml), with MIC90 values of 0.06, 0.03, and 0.5 μg/ml against Prevotella spp., Porphyromonas spp., and Fusobacterium spp., respectively. Clinical isolates of anaerobic Gram-positive cocci, Eggerthella spp., and Clostridium spp. were highly susceptible to razupenem (MIC90s, 0.03 to 1 μg/ml). PMID:21343447

Susceptibility of Respiratory Tract Anaerobes to Orally Administered Penicillins and Cephalosporins

PubMed Central

Busch, David F.; Kureshi, Lubna Afzal; Sutter, Vera L.; Finegold, Sydney M.

1976-01-01

Anaerobic bacteria recovered from airway-related infections were tested by agar dilution against selected penicillins and cephalosporins available for oral administration. Against 136 isolates, penicillins G and V showed comparable activity, particularly when pharmacological differences were considered. Although many isolates were exquisitely susceptible to the penicillins, only 55% of the Bacteroides species and 72% of all isolates were inhibited at 0.5 μg of penicillin G per ml. Results for penicillin V at 1 μg/ml were similar (59 and 73%). The two cephalosporins were more active at achievable levels, inhibiting 94 to 95% of Bacteroides and 95 to 96% of all isolates at 8 μg/ml. These levels represent approximately 50% of the reported peak serum levels after oral administration of 625 mg of the penicillins and 500 mg of the cephalosporins. Dicloxacillin and nafcillin were tested against 50 isolates. The two were comparably active on a weight basis; dicloxacillin was more active when pharmacological differences were considered, but did not match the other penicillins or the cephalosporins. PMID:984805

[Anaerobic Gram-negative bacilli involved in the etiopathogeny of the abscesses of superficial fascial spaces of the face and neck].

PubMed

Băncescu, Gabriela; Băncescu, A; Dumitriu, Silvia; Skaug, N

2008-01-01

The aim of this study was to isolate and identify at species level the strains of anaerobic Gram-negative bacilli (GNB) from pus samples collected in patients with abscesses of fascial spaces of the face and neck. Microscopy of Gram-stained smears and cultures were performed in each specimen. The strictly anaerobic GNB strains were identified using the conventional methods of diagnosis and the Rapid ID 32 A system. In addition, the other strains isolated in association with these bacteria were identified at least to genus level. The 28 anaerobic GNB isolates belonged to: Fusobacterium nucleatum and different species of Prevotella (4 species) and Bacteroides (3 species). The anaerobic GBN strains were recovered--either alone or in association with other migroorganisms--in more than half of all investigated samples and represented about 40% of all isolates. The most frequently isolated species were P> melaninogenica and B. ureolyticus.

Bacteroides fragilis induce necrosis on mice peritoneal macrophages: In vitro and in vivo assays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vieira, J.M.B.D., E-mail: jmanya@terra.com.br; Laboratorio de Biologia de Anaerobios, IMPPG, UFRJ, Rio de Janeiro; Seabra, S.H.

Bacteroides fragilis is an anaerobic bacteria component of human intestinal microbiota and agent of infections. In the host B. fragilis interacts with macrophages, which produces toxic radicals like NO. The interaction of activated mice peritoneal macrophages with four strains of B. fragilis was evaluated on this study. Previously was shown that such strains could cause metabolic and morphologic alterations related to macrophage death. In this work propidium iodide staining showed the strains inducing macrophage necrosis in that the labeling was evident. Besides nitroblue tetrazolium test showed that B. fragilis stimulates macrophage to produce oxygen radicals. In vivo assays performed inmore » BalbC mice have results similar to those for in vitro tests as well as scanning electron microscopy, which showed the same surface pore-like structures observed in vitro before. The results revealed that B. fragilis strains studied lead to macrophage death by a process similar to necrosis.« less

Mode of Birth Influences Preterm Infant Intestinal Colonization with Bacteroides Over the Early Neonatal Period

PubMed Central

Gregory, Katherine E.; LaPlante, Rose D.; Shan, Gururaj; Kumar, Deepak Vijaya; Gregas, Matt

2015-01-01

Background Intestinal colonization during infancy is important to short and long term health outcomes. Bacteroides, an early member of the intestinal microbiome, are necessary for breaking down complex molecules within the intestine and function to assist the body’s immune system in fighting against potentially harmful pathogens. Little is known about the colonization pattern of Bacteroides in preterm infants during the early neonatal period. Purpose This study measured Bacteroides colonization during the early neonatal period in a population of preterm infants based on clinical factors including mode of birth, antibiotics, and nutrition. Methods Bacterial DNA was isolated from 144 fecal samples from 29 preterm infants and analyzed using quantitative real time polymerase chain reaction (PCR). Analyses included liner mixed models to determine which clinical factors affect Bacteroides colonization of the infant gut. Results We found that infants born via vaginal canal had a higher rate of increase in Bacteroides than infants born via Cesarean section (p<.001). We did not find significant associations between antibiotic administration and differences in nutritional exposures with Bacteroides colonization. Implications for Practice These findings highlight the significant influence of mode of birth on Bacteroides colonization. While mode of birth is not always modifiable, these study findings may help develop interventions for preterm infants born via Cesarean section aimed at overcoming delayed Bacteroides colonization. Implications for Research Greater study of the intestinal microbiome and the clinical factors relevant to the preterm infant is needed so that interventions may be developed and tested, resulting in optimal microbial and immune health. PMID:26551793

Serum bactericidal activities of moxifloxacin and levofloxacin against aerobic and anaerobic intra-abdominal pathogens.

PubMed

Stein, Gary E; Schooley, Sharon; Tyrrell, Kerin L; Citron, Diane M; Nicolau, David P; Goldstein, Ellie J C

2008-02-01

We studied the serum bactericidal activity (SBA) of moxifloxacin and levofloxacin against common pathogens associated with complicated intra-abdominal infections. Ten healthy volunteers received a single dose of moxifloxacin (400 mg) and levofloxacin (750 mg) and serum samples were collected at 2, 4, 8, 12, and 24h after the dose of each drug. Bactericidal titers in serum over time were determined for aerobic gram-negative bacilli (Escherichia coli, Klebseilla pneumoniae, and Enterobacter cloacae) and anaerobic bacteria (Bacteroides fragilis, Bacteroides thetaiotaomicron, Prevotella bivia, and Finegoldia magna). Both fluoroquinolones provided rapid (2h) attainment and prolonged (24h) SBA (titers > or = 1:8) against each of the aerobic bacilli studied. SBA was observed for at least 12h against B. fragilis strains with MICs < or = 2 microg/ml to moxifloxacin and < or = 4 microg/ml to levofloxacin. Prolonged (12h) SBA (titers > or = 1:2) was also observed against isolates of B. thetaiotaomicron, P. bivia, and F. magna with moxifloxacin < or = MICs 2 microg/ml.

Azoreductase activity of anaerobic bacteria isolated from human intestinal microflora.

PubMed

Rafii, F; Franklin, W; Cerniglia, C E

1990-07-01

A plate assay was developed for the detection of anaerobic bacteria that produce azoreductases. With this plate assay, 10 strains of anaerobic bacteria capable of reducing azo dyes were isolated from human feces and identified as Eubacterium hadrum (2 strains), Eubacterium spp. (2 species), Clostridium clostridiiforme, a Butyrivibrio sp., a Bacteroides sp., Clostridium paraputrificum, Clostridium nexile, and a Clostridium sp. The average rate of reduction of Direct Blue 15 dye (a dimethoxybenzidine-based dye) in these strains ranged from 16 to 135 nmol of dye per min per mg of protein. The enzymes were inactivated by oxygen. In seven isolates, a flavin compound (riboflavin, flavin adenine dinucleotide, or flavin mononucleotide) was required for azoreductase activity. In the other three isolates and in Clostridium perfringens, no added flavin was required for activity. Nondenaturing polyacrylamide gel electrophoresis showed that each bacterium expressed only one azoreductase isozyme. At least three types of azoreductase enzyme were produced by the different isolates. All of the azoreductases were produced constitutively and released extracellularly.

In vivo imaging and tracking of host-microbiota interactions via metabolic labeling of gut anaerobic bacteria

PubMed Central

Geva-Zatorsky, Naama; Alvarez, David; Hudak, Jason E.; Reading, Nicola C.; Erturk-Hasdemir, Deniz; Dasgupta, Suryasarathi; von Andrian, Ulrich H.; Kasper, Dennis L.

2015-01-01

The intestine is densely populated by anaerobic commensal bacteria. These microorganisms shape immune system development, but our understanding of host–commensal interactions is hampered by a lack of tools for studying the anaerobic intestinal environment. We applied metabolic oligosaccharide engineering and bioorthogonal click-chemistry to label various commensal anaerobes, including Bacteroides fragilis, a common and immunologically important commensal. We studied the dissemination of B. fragilis following acute peritonitis, and characterized the interactions of the intact microbe and its polysaccharide components in myeloid and B cell lineages. The distribution and colonization of labeled B. fragilis along the intestine can be assessed, as well as niche competition following coadministration of multiple species of the microbiota. Nine additional anaerobic commensals (both gram-negative and gram-positive) from three phyla common in the gut—Bacteroidetes, Firmicutes, and Proteobacteria—and five families and one aerobic pathogen (Staphylococcus aureus) were also fluorescently labeled. This strategy permits visualization of the anaerobic microbial niche by various methods, including intravital two-photon microscopy and non-invasive whole-body imaging, and an approach to study microbial colonization and host–microbe interactions in real-time. PMID:26280120

In Vitro Activities of Y-688, a New 7-Substituted Fluoroquinolone, against Anaerobic Bacteria

PubMed Central

MacGowan, A. P.; Bowker, K. E.; Wootton, M.; Holt, H. A.; Reeves, D. S.

1998-01-01

The in vitro activities of Y-688, a new 7-substituted fluoroquinolone derivative, against 317 nonduplicate anaerobic isolates were determined. Eighty-five percent of the Bacteroides fragilis group (n = 89) were inhibited by ≤2 mg of Y-688 per liter, while 78, 100, 89, and 98% of gram-negative bacilli (n = 135), gram-positive cocci (n = 59), and non-spore-forming (n = 58) and spore-forming (n = 51) gram-positive bacilli, respectively, were inhibited by ≤1 mg of Y-688 per liter. PMID:9527797

Synergic activity, for anaerobes, of trovafloxacin with clindamycin or metronidazole: chequerboard and time-kill methods.

PubMed

Ednie, L M; Credito, K L; Khantipong, M; Jacobs, M R; Appelbaum, P C

2000-05-01

Chequerboard titrations were used to test the activity of trovafloxacin, alone and in combination with clindamycin or metronidazole, against 156 Gram-positive or Gram-negative anaerobes, including 47 Bacteroides fragilis group, 36 Prevotella spp., 26 fusobacteria, 21 peptostreptococci and 26 clostridia. MIC50/MIC90 values (mg/L) of each drug alone against all 156 strains were: trovafloxacin, 0.5/1; clindamycin, 0.25/2; metronidazole, 1/2. Synergy (FIC indices 0. 5-2.0); no antagonism (FIC indices >4.0) was seen. In addition, synergy was tested by time-kill methodology for each of the above combinations against 12 Gram-positive or Gram-negative strains. Results indicated that synergy (defined as a >/= 2 log(10) decrease in cfu/mL at 48 h compared with the more active drug alone) was found between trovafloxacin at or below the MIC and both clindamycin and metronidazole at or below the MIC in one strain each of Bacteroides fragilis, Bacteroides thetaiotaomicron, Prevotella intermedia, Fusobacterium varium, Peptostreptococcus asaccharolyticus and Clostridium bifermentans. Synergy between trovafloxacin (Bacteroides distasonis, Prevotella bivia, Fusobacterium mortiferum, P. asaccharolyticus and C. bifermentans. In many cases of synergy, including those at the trovafloxacin MIC, regrowth after 48 h, which was commonly seen with trovafloxacin alone, was inhibited, and 99.9% killing was observed with the combination after 48 h, but not with trovafloxacin alone.

Evidence for free-living Bacteroides in Cladophora along the shores of the Great Lakes

USGS Publications Warehouse

Whitman, Richard L.; Byappanahalli, Muruleedhara; Spoljaric, Ashley; Przybyla-Kelly, Katarzyna; Shively, Dawn A.; Nevers, Meredith

2014-01-01

Bacteroides is assumed to be restricted to the alimentary canal of animals and humans and is considered to be non-viable in ambient environments. We hypothesized that Bacteroides could persist and replicate within beach-stranded Cladophora glomerata mats in southern Lake Michigan, USA. Mean Bacteroides concentration (per GenBac3 Taqman quantitative PCR assay) during summer 2012 at Jeorse Park Beach was 5.2 log calibrator cell equivalents (CCE) g-1 dry weight (dw), ranging from 3.7 to 6.7. We monitored a single beach-stranded mat for 3 wk; bacterial concentrations increased by 1.6 log CCE g-1 dw and correlated significantly with ambient temperature (p = 0.003). Clonal growth was evident, as observed by >99% nucleotide sequence similarity among clones. In in vitro studies, Bacteroides concentrations increased by 5.5 log CCE g-1 after 7 d (27°C) in fresh Cladophora collected from rocks. Partial sequencing of the 16S rRNA gene of 36 clones from the incubation experiment showed highly similar genotypes (≥97% sequence overlap). The closest enteric Bacteroides spp. from the National Center for Biotechnology Information database were only 87 to 91% similar. Genomic similarity, clonality, growth, and persistence collectively suggest that putative, free-living Bacteroides inhabit Cladophora mats of southern Lake Michigan. These findings may have important biological, medical, regulatory, microbial source tracking, and public health implications.

Fine Structure of Bacteroids in Root Nodules of Vigna sinensis, Acacia longifolia, Viminaria juncea, and Lupinus angustifolius

PubMed Central

Dart, P. J.; Mercer, F. V.

1966-01-01

Dart, P. J. (University of Sydney, Sydney, Australia), and F. V. Mercer. Fine structure of bacteroids in root nodules of Vigna sinensis, Acacia longifolia, Viminaria juncea, and Lupinus angustifolius. J. Bacteriol. 91:1314–1319.—In nodules of Vigna sinensis, Acacia longifolia, and Viminaria juncea, membrane envelopes enclose groups of bacteroids. The bacteroids often contain inclusion granules and electron-dense bodies, expand little during development, and retain their rod form with a compact, central nucleoid area. The membrane envelope may persist around bacteroids after host cytoplasm breakdown. In nodules of Lupinus angustifolius, the membrane envelopes enclose only one or two bacteroids, which expand noticeably during development and change from their initial rod structure. Images PMID:5929757

Bacteroides fragilis RecA protein overexpression causes resistance to metronidazole

PubMed Central

Steffens, Laura S.; Nicholson, Samantha; Paul, Lynthia V.; Nord, Carl Erik; Patrick, Sheila; Abratt, Valerie R.

2010-01-01

Bacteroides fragilis is a human gut commensal and an opportunistic pathogen causing anaerobic abscesses and bacteraemias which are treated with metronidazole (Mtz), a DNA damaging agent. This study examined the role of the DNA repair protein, RecA, in maintaining endogenous DNA stability and its contribution to resistance to Mtz and other DNA damaging agents. RT-PCR of B. fragilis genomic DNA showed that the recA gene was co-transcribed as an operon together with two upstream genes, putatively involved in repairing oxygen damage. A B. fragilis recA mutant was generated using targeted gene inactivation. Fluorescence microscopy using DAPI staining revealed increased numbers of mutant cells with reduced intact double-stranded DNA. Alkaline gel electrophoresis of the recA mutant DNA showed increased amounts of strand breaks under normal growth conditions, and the recA mutant also showed less spontaneous mutagenesis relative to the wild type strain. The recA mutant was sensitive to Mtz, ultraviolet light and hydrogen peroxide. A B. fragilis strain overexpressing the RecA protein exhibited increased resistance to Mtz compared to the wild type. This is the first study to show that overexpression of a DNA repair protein in B. fragilis increases Mtz resistance. This represents a novel drug resistance mechanism in this bacterium. PMID:20435137

Molecular studies of fecal anaerobic commensal bacteria in acute diarrhea in children.

PubMed

Balamurugan, Ramadass; Janardhan, Harish P; George, Sarah; Raghava, M Venkata; Muliyil, Jayaprakash; Ramakrishna, Balakrishnan S

2008-05-01

The commensal bacterial flora of the colon may undergo changes during diarrhea, owing to colonization of the intestine by pathogens and to rapid intestinal transit. This study used molecular methods to determine changes in the composition of selected commensal anaerobic bacteria during and after acute diarrhea in children. Fecal samples were obtained from 46 children with acute diarrhea in a rural community during an episode of acute diarrhea, immediately after recovery from diarrhea, and 3 months after recovery. DNA was extracted and quantitative polymerase chain reaction using SYBR green and genus- and species-specific primers targeting 16S rDNA were undertaken to quantitate the following groups of bacteria: Bifidobacterium spp., Bifidobacterium longum group, Bacteroides-Prevotella group, Bacteroides fragilis, Lactobacillus acidophilus group, Faecalibacterium prauznitzii, and Eubacterium rectale, relative to amplification of universal bacterial domain 16S rDNA. Bacteria belonging to the Bacteroides-Prevotella-Porphyromonas group, E rectale, L acidophilus, and F prauznitzii groups were low during acute diarrhea compared with their levels after recovery from diarrhea. The pattern was similar in rotavirus diarrhea and nonrotavirus diarrhea. Administration of amylase-resistant maize starch as adjuvant therapy was associated with lower levels of F prauznitzii at the time of recovery but did not lead to other changes in the floral pattern. Specific classes of fecal bacteria are lower during episodes of acute diarrhea in children than during periods of normal gastrointestinal health, suggesting specific alterations in the flora during diarrhea.

Bioluminescence Imaging to Track Bacteroides fragilis Inhibition of Vibrio parahaemolyticus Infection in Mice.

PubMed

Li, Zhengchao; Deng, Huimin; Zhou, Yazhou; Tan, Yafang; Wang, Xiaoyi; Han, Yanping; Liu, Yangyang; Wang, Ye; Yang, Ruifu; Bi, Yujing; Zhi, Fachao

2017-01-01

Bacteroides fragilis is an anaerobic, Gram-negative, commensal bacterium of the human gut. It plays an important role in promoting the maturation of the immune system, as well as suppressing abnormal inflammation. Many recent studies have focused on the relationship between B. fragilis and human immunity, and indicate that B. fragilis has many useful probiotic effects. As inhibition of intestinal pathogens is an important characteristic of probiotic strains, this study examined whether B. fragilis could inhibit pathogenic bacteria. Results showed that Vibrio parahaemolyticus was inhibited by B. fragilis in vitro , and that B. fragilis could protect both RAW 264.7 and LoVo cells from damage caused by V. parahaemolyticus . Using in vivo imaging, we constructed a light-emitting V. parahaemolyticus strain and showed that B. fragilis might shorten the colonization time and reduce the number of lux -expressing bacteria in a mouse model. These results provide useful information for developing B. fragilis into a probiotic product, and also indicate that this commensal bacterium might aid in the clinical treatment of gastroenteritis caused by V. parahaemolyticus .

Bioluminescence Imaging to Track Bacteroides fragilis Inhibition of Vibrio parahaemolyticus Infection in Mice

PubMed Central

Li, Zhengchao; Deng, Huimin; Zhou, Yazhou; Tan, Yafang; Wang, Xiaoyi; Han, Yanping; Liu, Yangyang; Wang, Ye; Yang, Ruifu; Bi, Yujing; Zhi, Fachao

2017-01-01

Bacteroides fragilis is an anaerobic, Gram-negative, commensal bacterium of the human gut. It plays an important role in promoting the maturation of the immune system, as well as suppressing abnormal inflammation. Many recent studies have focused on the relationship between B. fragilis and human immunity, and indicate that B. fragilis has many useful probiotic effects. As inhibition of intestinal pathogens is an important characteristic of probiotic strains, this study examined whether B. fragilis could inhibit pathogenic bacteria. Results showed that Vibrio parahaemolyticus was inhibited by B. fragilis in vitro, and that B. fragilis could protect both RAW 264.7 and LoVo cells from damage caused by V. parahaemolyticus. Using in vivo imaging, we constructed a light-emitting V. parahaemolyticus strain and showed that B. fragilis might shorten the colonization time and reduce the number of lux-expressing bacteria in a mouse model. These results provide useful information for developing B. fragilis into a probiotic product, and also indicate that this commensal bacterium might aid in the clinical treatment of gastroenteritis caused by V. parahaemolyticus. PMID:28553617

Recognition of anaerobic bacterial isolates in vitro using electronic nose technology.

PubMed

Pavlou, A; Turner, A P F; Magan, N

2002-01-01

Use of an electronic nose (e.nose) system to differentiation between anaerobic bacteria grown in vitro on agar media. Cultures of Clostridium spp. (14 strains) and Bacteroides fragilis (12 strains) were grown on blood agar plates and incubated in sampling bags for 30 min before head space analysis of the volatiles. Qualitative analyses of the volatile production patterns was carried out using an e.nose system with 14 conducting polymer sensors. Using data analysis techniques such as principal components analysis (PCA), genetic algorithms and neural networks it was possible to differentiate between agar blanks and individual species which accounted for all the data. A total of eight unknowns were correctly discriminated into the bacterial groups. This is the first report of in vitro complex volatile pattern recognition and differentiation of anaerobic pathogens. These results suggest the potential for application of e.nose technology in early diagnosis of microbial pathogens of medical importance.

Transcriptomic dissection of Bradyrhizobium sp. strain ORS285 in symbiosis with Aeschynomene spp. inducing different bacteroid morphotypes with contrasted symbiotic efficiency.

PubMed

Lamouche, Florian; Gully, Djamel; Chaumeret, Anaïs; Nouwen, Nico; Verly, Camille; Pierre, Olivier; Sciallano, Coline; Fardoux, Joël; Jeudy, Christian; Szücs, Attila; Mondy, Samuel; Salon, Christophe; Nagy, István; Kereszt, Attila; Dessaux, Yves; Giraud, Eric; Mergaert, Peter; Alunni, Benoit

2018-06-19

To circumvent the paucity of nitrogen sources in the soil legume plants establish a symbiotic interaction with nitrogen-fixing soil bacteria called rhizobia. During symbiosis, the plants form root organs called nodules, where bacteria are housed intracellularly and become active nitrogen fixers known as bacteroids. Depending on their host plant, bacteroids can adopt different morphotypes, being either unmodified (U), elongated (E) or spherical (S). E- and S-type bacteroids undergo a terminal differentiation leading to irreversible morphological changes and DNA endoreduplication. Previous studies suggest that differentiated bacteroids display an increased symbiotic efficiency (E>U and S>U). In this study, we used a combination of Aeschynomene species inducing E- or S-type bacteroids in symbiosis with Bradyrhizobium sp. ORS285 to show that S-type bacteroids present a better symbiotic efficiency than E-type bacteroids. We performed a transcriptomic analysis on E- and S-type bacteroids formed by Aeschynomene afraspera and Aeschynomene indica nodules and identified the bacterial functions activated in bacteroids and specific to each bacteroid type. Extending the expression analysis in E- and S-type bacteroids in other Aeschynomene species by qRT-PCR on selected genes from the transcriptome analysis narrowed down the set of bacteroid morphotype-specific genes. Functional analysis of a selected subset of 31 bacteroid-induced or morphotype-specific genes revealed no symbiotic phenotypes in the mutants. This highlights the robustness of the symbiotic program but could also indicate that the bacterial response to the plant environment is partially anticipatory or even maladaptive. Our analysis confirms the correlation between differentiation and efficiency of the bacteroids and provides a framework for the identification of bacterial functions that affect the efficiency of bacteroids. This article is protected by copyright. All rights reserved. © 2018 Society for Applied

Amino Acid and Vitamin Requirements of Several Bacteroides Strains

PubMed Central

Quinto, Grace

1966-01-01

Nutritional studies were performed on nine Bacteroides strains, by use of the methodology and media of anaerobic rumen microbiology. Ristella perfoetens CCI required l-arginine hydrochloride, l-tryptophan, l-leucine, l-histidine hydrochloride, l-cysteine hydrochloride, dl-valine, dl-tyrosine, and the vitamin calcium-d-pantothenate, since scant turbidity developed in media without these nutrients. R. perfoetens was stimulated by glycine, dl-lysine hydrochloride, dl-isoleucine, l-proline, l-glutamic acid, dl-alanine, dl-phenylalanine, dl-methionine, and the vitamins nicotinamide and p-aminobenzoic acid, since maximal turbidity developed more slowly in media without these nutrients than in complete medium. Medium A-23, which was devised for R. perfoetens, contained salts, 0.0002% nicotinamide and calcium d-pantothenate, 0.00001% p-aminobenzoic acid, 0.044% l-tryptophan, 0.09% l-glutamic acid, and 0.1% of the other 13 amino acids listed above. Zuberella clostridiformis and seven strains of R. pseudoinsolita did not require vitamins, and showed no absolute requirement for any one amino acid. Various strains produced maximal turbidity more slowly in media deficient in l-proline, glycine, l-glutamic acid, dl-serine, l-histidine hydrochloride, dl-alanine, or l-cysteine hydrochloride, than in complete medium. These eight strains grew optimally in medium A-23 plus 0.1% dl-serine but without vitamins. PMID:16349673

Relative adherence of Bacteroides species and strains to Actinomyces viscosus on saliva-coated hydroxyapatite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, J.; Ellen, R.P.

1989-09-01

The study was designed to compare the adherence of several Bacteroides species to A. viscosus. Using 3H, we labeled 24 laboratory strains, including 13 Bacteroides species and 11 fresh clinical isolates of three Bacteroides species. Their adherence to A. viscosus bound to a saliva-coated mineral surface was quantified by liquid scintillation. Adherence relative to a standard strain, B. gingivalis 2561, was compared. Among the lab bacteroides, those of B. gingivalis (eight strains) were the greatest binders (mean, 80.5 {plus minus} 12.4%). Strains of other lab bacteroides bound less well (mean, 33.4 {plus minus} 6.3%). The difference in means was statisticallymore » significant (p less than 0.01). The mean for B. gingivalis strains was also significantly greater than that for strains of B. intermedius (51.7 {plus minus} 6.2%). Attachment of B. gingivalis was saturable in experiments in which either input concentration or time was the independent variable, indicating that B. gingivalis cells do not accumulate in this vitro simulation of plaque formation by binding to each other. Subculture did not seem to affect the degree of binding.« less

Spirochaeta americana sp. nov., a new haloalkaliphilic, obligately anaerobic spirochaete isolated from soda Mono Lake in California

NASA Technical Reports Server (NTRS)

Hoover, Richard B.; Pikuta, Elena V.; Bej, Asim K.; Marsic, Damien; Whitman, William B.; Tang, Jane; Krader, Paul

2003-01-01

A novel, obligately anaerobic, mesophilic, haloalkaliphilic spirochaete, strain ASpG1(T), was isolated from sediments of the alkaline, hypersaline Mono Lake in California, USA. Cells of the Gram-negative strain were motile and spirochaete-shaped with sizes of 0.2-0.22 x 8-18 microm. Growth of the strain was observed between 10 and 44 degrees C (optimum 37 degrees C), in 2-12% (w/v) NaCl (optimum 3% NaCl) and between pH 8 and 10.5 (optimum pH 9.5). The novel strain was strictly alkaliphilic, required high concentrations of carbonates in the medium and was capable of utilizing D-glucose, fructose, maltose, sucrose, starch and D-mannitol. End products of glucose fermentation were H2, acetate, ethanol and formate. Strain ASpG(T) was resistant to kanamycin and rifampicin, but sensitive to gentamicin, tetracycline and chloramphenicol. The G + C content of its DNA was 58.5 mol%. DNA-DNA hybridization analysis of strain ASpG1(T) with its most closely related species, Spirochaeta alkalica Z-7491(T), revealed a hybridization value of only 48.7%. On the basis of its physiological and molecular properties, strain ASpG1(T) appears to represent a novel species of the genus Spirochaeta, for which the name Spirochaeta americana is proposed (type strain ASpG1(T) =ATCC BAA-392(T) = DSM 14872(T)).

Update on the taxonomy and the clinical and laboratory characteristics of pigmented anaerobic gram-negative rods.

PubMed

Jousimies-Somer, H R

1995-06-01

Pigmented anaerobic gram-negative rods are currently categorized as 17 species distributed in three genera: Prevotella, Porphyromonas, and Bacteroides. These organisms are often encountered in clinical specimens but are also found as part of the indigenous flora on various mucosal surfaces. Several studies are presently assessing the association of individual species with health and disease. For example, Porphyromonas gingivalis and Porphyromonas endodontalis are key putative pathogens in adult periodontitis and root canal infections, respectively. Porphyromonas asaccharolytica is prevalent in extraoral infections. The Porphyromonas species of animal origin have been isolated from infected bite wounds in humans. Isolates closely resembling Bacteroides levii have been recovered from various types of human infections. According to preliminary reports, Prevotella intermedia tends to be associated more often with periodontal disease than with a healthy oral cavity. In the laboratory, enzyme profiling facilitates the identification of these pigmented rods. Beta-Lactamase production is more common among prevotella species (30%-50%) than among Porphyromonas species (< 10%).

Lincomycins in the Treatment of Bacteroides Infections

PubMed Central

Tracy, Oonagh; Gordon, A. M.; Moran, F.; Love, W. C.; McKenzie, Peter

1972-01-01

Lincomycin, or the closely related derivative clindamycin, was used to treat six patients with bacteroides infection. In five of the six there was a rapid clinical response to the treatment. Lincomycin and clindamycin seem to be the antibiotics of choice for such infections. PMID:5008478

Identification of feces by detection of Bacteroides genes.

PubMed

Nakanishi, Hiroaki; Shojo, Hideki; Ohmori, Takeshi; Hara, Masaaki; Takada, Aya; Adachi, Noboru; Saito, Kazuyuki

2013-01-01

In forensic science, the identification of feces is very important in a variety of crime investigations. However, no sensitive and simple fecal identification method using molecular biological techniques has been reported. Here, we focused on the fecal bacteria, Bacteroides uniformis, Bacteroides vulgatus and Bacteroides thetaiotaomicron, and developed a novel fecal identification method by detection of the gene sequences specific to these bacteria in various body (feces, blood, saliva, semen, urine, vaginal fluids and skin surfaces) and forensic (anal adhesions) specimens. Bacterial gene detection was performed by real-time PCR using a minor groove binding probe to amplify the RNA polymerase β-subunit gene of B. uniformis and B. vulgatus, and the α-1-6 mannanase gene of B. thetaiotaomicron. At least one of these bacteria was detected in the feces of 20 donors; the proportions of B. uniformis, B. vulgatus and B. thetaiotaomicron were 95, 85 and 60%, respectively. Bacteroides vulgatus was also detected in one of six vaginal fluid samples, but B. thetaiotaomicron and B. uniformis were not detected in body samples other than feces. Further, we applied this method to forensic specimens from 18 donors. Eighteen anal adhesions also contained at least one of three bacteria; B. uniformis, B. vulgatus and B. thetaiotaomicron were detected in 89, 78 and 56%, respectively, of the specimens. Thus, these bacteria were present at a high frequency in the fecal and forensic specimens, while either B. uniformis or B. vulgatus was detected in all samples. Therefore, B. uniformis and B. vulgatus represent more appropriate target species than B. thetaiotaomicron for the identification of fecal material. If B. vulgatus and/or B. uniformis are detected, it is likely that the sample contains feces. Taken together, our results suggest that the use of molecular biological techniques will aid the detection of feces in forensic practice, although it is possible that the samples contained

Putative Porin of Bradyrhizobium sp. (Lupinus) Bacteroids Induced by Glyphosate▿

PubMed Central

de María, Nuria; Guevara, Ángeles; Serra, M. Teresa; García-Luque, Isabel; González-Sama, Alfonso; de Lacoba, Mario García; de Felipe, M. Rosario; Fernández-Pascual, Mercedes

2007-01-01

Application of glyphosate (N-[phosphonomethyl] glycine) to Bradyrhizobium sp. (Lupinus)-nodulated lupin plants caused modifications in the protein pattern of bacteroids. The most significant change was the presence of a 44-kDa polypeptide in bacteroids from plants treated with the higher doses of glyphosate employed (5 and 10 mM). The polypeptide has been characterized by the amino acid sequencing of its N terminus and the isolation and nucleic acid sequencing of its encoding gene. It is putatively encoded by a single gene, and the protein has been identified as a putative porin. Protein modeling revealed the existence of several domains sharing similarity to different porins, such as a transmembrane beta-barrel. The protein has been designated BLpp, for Bradyrhizobium sp. (Lupinus) putative porin, and would be the first porin described in Bradyrhizobium sp. (Lupinus). In addition, a putative conserved domain of porins has been identified which consists of 87 amino acids, located in the BLpp sequence 30 amino acids downstream of the N-terminal region. In bacteroids, mRNA of the BLpp gene shows a basal constitutive expression that increases under glyphosate treatment, and the expression of the gene is seemingly regulated at the transcriptional level. By contrast, in free-living bacteria glyphosate treatment leads to an inhibition of BLpp mRNA accumulation, indicating a different effect of glyphosate on BLpp gene expression in bacteroids and free-living bacteria. The possible role of BLpp in a metabolite interchange between Bradyrhizobium and lupin is discussed. PMID:17557843

Megasphaera indica sp. nov., an obligate anaerobic bacteria isolated from human faeces.

PubMed

Lanjekar, V B; Marathe, N P; Ramana, V Venkata; Shouche, Y S; Ranade, D R

2014-07-01

Two coccoid, non-motile, obligately anaerobic, Gram-stain-negative bacteria, occurring singly or in pairs, or as short chains, with a mean size of 1.4-2.5 µm were isolated from the faeces of two healthy human volunteers, aged 26 and 56 years, and were designated NMBHI-10(T) and BLPYG-7, respectively. Both the strains were affiliated to the sub-branch Sporomusa of the class Clostridia as revealed by 16S rRNA gene sequence analysis. The isolates NMBHI-10(T) and BLPYG-7 showed 99.1 and 99.2% 16S rRNA gene sequence similarity, respectively, with Megasphaera elsdenii JCM 1772(T). DNA-DNA hybridization and phenotypic analysis showed that both the strains were distinct from their closest relative, M. elsdenii JCM 1772(T) (42 and 53% DNA-DNA relatedness with NMBHI-10(T) and BLPYG-7, respectively), but belong to the same species (DNA-DNA relatedness of 80.9 % between the isolates). According to DNA-DNA hybridization results, the coccoid strains belong to the same genospecies, and neither is related to any of the recognized species of the genus Megasphaera. Strains NMBHI-10(T) and BLPYG-7 grew in PYG broth at temperatures of between 15 and 40 °C (optimum 37 °C), but not at 45 °C. The strains utilized a range of carbohydrates as sources of carbon and energy including glucose, lactose, cellobiose, rhamnose, galactose and sucrose. Glucose fermentation resulted in the formation of volatile fatty acids, mainly caproic acid and organic acids such as succinic acid. Phylogenetic analysis, specific phenotypic characteristics and/or DNA G+C content also differentiated the strains from each other and from their closest relatives. The DNA G+C contents of strains NMBHI-10(T) and BLPYG-7 are 57.7 and 54.9 mol%, respectively. The major fatty acids were 12 : 0 FAME and 17 : 0 CYC FAME. On the basis of these data, we conclude that strains NMBHI-10(T) and BLPYG-7 should be classified as representing a novel species of the genus Megasphaera, for which the name Megsphaera indica sp. nov

Potential application of anaerobic extremophiles for hydrogen production

NASA Astrophysics Data System (ADS)

Pikuta, Elena V.; Hoover, Richard B.

2004-11-01

In processes of the substrate fermentation most anaerobes produce molecular hydrogen as a waste end product, which often controls the culture growth as an inhibitor. Usually in nature the hydrogen is easily removed from an ecosystem, due to its physical features, and an immediate consumption by the secondary anaerobes that sometimes behave as competitors for electron donors; a classical example of this kind of substrate competition in anaerobic microbial communities is the interaction between methanogens and sulfate- or sulfur-reducers. Previously, on the mixed cultures of anaerobes at neutral pH, it was demonstrated that bacterial hydrogen production could provide a good alternative energy source. At neutral pH the original cultures could easily contaminated by methanogens, and the most unpleasant side effect of these conditions is the development of pathogenic bacteria. In both cases the rate of hydrogen production was dramatically decreased since some part of the hydrogen was transformed to methane, and furthermore, the cultivation with pathogenic contaminants on an industrial scale would create an unsafe situation. In our laboratory the experiments with obligately alkaliphilic bacteria producing hydrogen as an end metabolic product were performed at different conditions. The mesophilic, haloalkaliphilic and obligately anaerobic bacterium Spirochaeta americana ASpG1T was studied and various cultivation regimes were compared for the most effective hydrogen production. In a highly mineralized media with pH 9.5-10.0 not many known methanogens are capable of growth, and the probability of developing pathogenic contaminants is theoretically is close to zero (in medicine carbonate- saturated solutions are applied as antiseptics). Therefore the cultivation of alkaliphilic hydrogen producing bacteria could be considered as a safe and economical process for large-scale industrial bio-hydrogen production in the future. Here we present and discuss the experimental data

Azoreductase activity of anaerobic bacteria isolated from human intestinal microflora.

PubMed Central

Rafii, F; Franklin, W; Cerniglia, C E

1990-01-01

A plate assay was developed for the detection of anaerobic bacteria that produce azoreductases. With this plate assay, 10 strains of anaerobic bacteria capable of reducing azo dyes were isolated from human feces and identified as Eubacterium hadrum (2 strains), Eubacterium spp. (2 species), Clostridium clostridiiforme, a Butyrivibrio sp., a Bacteroides sp., Clostridium paraputrificum, Clostridium nexile, and a Clostridium sp. The average rate of reduction of Direct Blue 15 dye (a dimethoxybenzidine-based dye) in these strains ranged from 16 to 135 nmol of dye per min per mg of protein. The enzymes were inactivated by oxygen. In seven isolates, a flavin compound (riboflavin, flavin adenine dinucleotide, or flavin mononucleotide) was required for azoreductase activity. In the other three isolates and in Clostridium perfringens, no added flavin was required for activity. Nondenaturing polyacrylamide gel electrophoresis showed that each bacterium expressed only one azoreductase isozyme. At least three types of azoreductase enzyme were produced by the different isolates. All of the azoreductases were produced constitutively and released extracellularly. Images PMID:2202258

5S ribosomal ribonucleic acid sequences in Bacteroides and Fusobacterium: evolutionary relationships within these genera and among eubacteria in general

NASA Technical Reports Server (NTRS)

Van den Eynde, H.; De Baere, R.; Shah, H. N.; Gharbia, S. E.; Fox, G. E.; Michalik, J.; Van de Peer, Y.; De Wachter, R.

1989-01-01

The 5S ribosomal ribonucleic acid (rRNA) sequences were determined for Bacteroides fragilis, Bacteroides thetaiotaomicron, Bacteroides capillosus, Bacteroides veroralis, Porphyromonas gingivalis, Anaerorhabdus furcosus, Fusobacterium nucleatum, Fusobacterium mortiferum, and Fusobacterium varium. A dendrogram constructed by a clustering algorithm from these sequences, which were aligned with all other hitherto known eubacterial 5S rRNA sequences, showed differences as well as similarities with respect to results derived from 16S rRNA analyses. In the 5S rRNA dendrogram, Bacteroides clustered together with Cytophaga and Fusobacterium, as in 16S rRNA analyses. Intraphylum relationships deduced from 5S rRNAs suggested that Bacteroides is specifically related to Cytophaga rather than to Fusobacterium, as was suggested by 16S rRNA analyses. Previous taxonomic considerations concerning the genus Bacteroides, based on biochemical and physiological data, were confirmed by the 5S rRNA sequence analysis.

Extensive Mobilome-Driven Genome Diversification in Mouse Gut-Associated Bacteroides vulgatus mpk

PubMed Central

Lange, Anna; Beier, Sina; Steimle, Alex; Autenrieth, Ingo B.; Huson, Daniel H.; Frick, Julia-Stefanie

2016-01-01

Like many other Bacteroides species, Bacteroides vulgatus strain mpk, a mouse fecal isolate which was shown to promote intestinal homeostasis, utilizes a variety of mobile elements for genome evolution. Based on sequences collected by Pacific Biosciences SMRT sequencing technology, we discuss the challenges of assembling and studying a bacterial genome of high plasticity. Additionally, we conducted comparative genomics comparing this commensal strain with the B. vulgatus type strain ATCC 8482 as well as multiple other Bacteroides and Parabacteroides strains to reveal the most important differences and identify the unique features of B. vulgatus mpk. The genome of B. vulgatus mpk harbors a large and diverse set of mobile element proteins compared with other sequenced Bacteroides strains. We found evidence of a number of different horizontal gene transfer events and a genome landscape that has been extensively altered by different mobilization events. A CRISPR/Cas system could be identified that provides a possible mechanism for preventing the integration of invading external DNA. We propose that the high genome plasticity and the introduced genome instabilities of B. vulgatus mpk arising from the various mobilization events might play an important role not only in its adaptation to the challenging intestinal environment in general, but also in its ability to interact with the gut microbiota. PMID:27071651

[Anaerobic bacteria 150 years after their discovery by Pasteur].

PubMed

García-Sánchez, José Elías; García-Sánchez, Enrique; Martín-Del-Rey, Ángel; García-Merino, Enrique

2015-02-01

In 2011 we celebrated the 150th anniversary of the discovery of anaerobic bacteria by Louis Pasteur. The interest of the biomedical community on such bacteria is still maintained, and is particularly focused on Clostridium difficile. In the past few years important advances in taxonomy have been made due to the genetic, technological and computing developments. Thus, a significant number of new species related to human infections have been characterised, and some already known have been reclassified. At pathogenic level some specimens of anaerobic microflora, that had not been isolated from human infections, have been now isolated in some clinical conditions. There was emergence (or re-emergence) of some species and clinical conditions. Certain anaerobic bacteria have been associated with established infectious syndromes. The virulence of certain strains has increased, and some hypotheses on their participation in certain diseases have been given. In terms of diagnosis, the routine use of MALDI-TOF has led to a shortening of time and a cost reduction in the identification, with an improvement directly related to the improvement of data bases. The application of real-time PCR has been another major progress, and the sequencing of 16srRNA gene and others is currently a reality for several laboratories. Anaerobes have increased their resistance to antimicrobial agents, and the emergence of resistance to carbapenems and metronidazole, and multi-resistance is a current reality. In this situation, linezolid could be an effective alternative for Bacteroides. Fidaxomicin is the only anti-anaerobic agent introduced in the recent years, specifically for the diarrhoea caused by C.difficile. Moreover, some mathematical models have also been proposed in relation with this species. Copyright © 2013 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Spirochaeta Americana Sp. Nov., A new Haloalkaliphilic, Obligately Anaerobic Spirochete Isolated from Soda Mono Lake in California

NASA Technical Reports Server (NTRS)

Hoover, Richard B.; Pikuta, Elena V.; Bej, Asim K.; Marsic, Damien; Whitman, William B.; Tang, Jane; Krader, Paul; Six, N. Frank (Technical Monitor)

2002-01-01

A novel obligately anaerobic, mesophilic, haloalkaliphilic spirochete, strain ASpG1(sup T), was isolated from sediments of the alkaline, hypersaline Mono Lake in California, U.S.A. The Gram-negative cells are motile and spirochete-shaped with sizes of 0.2 - 0.22 X 8-15 microns. Growth was observed over the following ranges: temperature 10 C to 44 C; optimum +37 C; NaCl concentration 2 - 12 % (w/v); optimum NaCl3 % and pH 8 - 10.5; optimum pH 9.5. The novel isolate is strictly alkaliphilic, requires high concentrations of carbonate in the medium, and is capable of utilizing D-glucose, fructose, maltose, sucrose, starch, and D-mannitol. The main end products of glucose fermentation are: H2, acetate, ethanol, and formate. Strain ASpG(sup T) is resistant to kanamycin, and rifampin, but sensitive to chloramphenicol, gentamycin and tetracycline. The G+C content of its DNA is 58.5 mol%, genome size is 2.98 x l0(exp 9) Daltons, Tm of the genomic DNA is 68 +/- 2 C, and DNA-DNA hybridization with the most closely related species, Spirocheta alkalica Strain Z-7491(sup T), exhibited 48.7% homology. On the basis of its physiological and molecular properties, the isolate appears to be a novel species of the genus Spirochaeta; and the name Spirochaeta americana sp. nov., is proposed for the taxon (type strain ASpG1(sup T) = ATCC BAA-392(sup T) = DSMZ 14872(sup T)).

Spirochaeta Americana sp. Nov., A New Haloalkaliphilic, Obligately Anaerobic Spirochaete Isolated from Soda Mona Lake in California

NASA Technical Reports Server (NTRS)

Hoover, Richard B.; Pikuta, Elena V.; Bej, Asim K.; Marsic, Damien; Whitman, William B.; Tang, Jane; Krader, Paul

2003-01-01

A novel, obligately anaerobic, mesophilic, haloalkaliphilic spirochaete, strain ASpG1(sup T), was isolated from sediments of the alkaline, hypersaline Mono Lake in California, USA. Cells of the Gram-negative strain were motile and spirochaete-shaped with sizes of 0.2-0.22 x 8-18 microns. Growth of the strain was observed between 10 and 44 C (optimum 37 C), in 2-12% (w/v) NaCl (optimum 3 % NaCl) and between pH 8 and 10.5 (optimum pH 9.5). The novel strain was strictly alkaliphilic, required high concentrations of carbonates in the medium and was capable of utilizing D-glucose, fructose, maltose, sucrose, starch and D-mannitol. End products of glucose fermentation were H2, acetate, ethanol and formate. Strain ASpG1(sup T) was resistant to kanamycin and rifampicin, but sensitive to gentamicin, tetracycline and chloramphenicol. The G + C content of its DNA was 58.5 mol%. DNA-DNA hybridization analysis of strain ASpG1(sup T) with its most closely related species, Spirochaeta alkalica Z-7491(sup T) revealed a hybridization value of only 48.7 %. On the basis of its physiological and molecular properties, strain ASpG1(sup T) appears to represent a novel species of the genus Spirochaeta, for which the name Spirochaeta americana is proposed (type strain ASpG1(sup T) = ATCC 13AA-392(sup T) = DSM 14872(sup T)).

An obligately aerobic soil bacterium activates fermentative hydrogen production to survive reductive stress during hypoxia.

PubMed

Berney, Michael; Greening, Chris; Conrad, Ralf; Jacobs, William R; Cook, Gregory M

2014-08-05

Oxygen availability is a major factor and evolutionary force determining the metabolic strategy of bacteria colonizing an environmental niche. In the soil, conditions can switch rapidly between oxia and anoxia, forcing soil bacteria to remodel their energy metabolism accordingly. Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes. Here we show that an obligate aerobe, the soil actinomycete Mycobacterium smegmatis, adopts an anaerobe-type strategy by activating fermentative hydrogen production to adapt to hypoxia. This process is controlled by the two-component system DosR-DosS/DosT, an oxygen and redox sensor that is well conserved in mycobacteria. We show that DosR tightly regulates the two [NiFe]-hydrogenases: Hyd3 (MSMEG_3931-3928) and Hyd2 (MSMEG_2719-2718). Using genetic manipulation and high-sensitivity GC, we demonstrate that Hyd3 facilitates the evolution of H2 when oxygen is depleted. Combined activity of Hyd2 and Hyd3 was necessary to maintain an optimal NAD(+)/NADH ratio and enhanced adaptation to and survival of hypoxia. We demonstrate that fermentatively-produced hydrogen can be recycled when fumarate or oxygen become available, suggesting Mycobacterium smegmatis can switch between fermentation, anaerobic respiration, and aerobic respiration. Hydrogen metabolism enables this obligate aerobe to rapidly meet its energetic needs when switching between microoxic and anoxic conditions and provides a competitive advantage in low oxygen environments.

Induction of anaerobic, photoautotrophic growth in the cyanobacterium Oscillatoria limnetica.

PubMed Central

Oren, A; Padan, E

1978-01-01

Anaerobic photoautotrophic growth of the cyanobacterium Oscillatoria limnetica was demonstrated under nitrogen in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (5micron), a constant concentration of Na2S (2.5 mM), and constant pH (7.3). The photoanaerobic growth rate (2 days doubling time) was similar to that obtained under oxygenic photoautotrophic growth conditions. The potential of oxygenic photosynthesis is constitutive in the cells; that of anoxygenic photosynthesis is rapidly (2 h) induced in the presence of Na2S in the light in a process requiring protein synthesis. The facultative anaerobic phototrophic growth physiology exhibited by O. limnetica would seem to represent an intermediate physiological pattern between the obligate anaerobic one of photosynthetic bacteria and the oxygenic one of eucaryotic algae. PMID:415043

Complete Genome Sequence of Bacteroides ovatus V975

PubMed Central

Goesmann, Alexander; Carding, Simon R.

2016-01-01

The complete genome sequence of Bacteroides ovatus V975 was determined. The genome consists of a single circular chromosome of 6,475,296 bp containing five rRNA operons, 68 tRNA genes, and 4,959 coding genes. PMID:27908995

Activation of Acetone and Other Simple Ketones in Anaerobic Bacteria.

PubMed

Heider, Johann; Schühle, Karola; Frey, Jasmin; Schink, Bernhard

2016-01-01

Acetone and other ketones are activated for subsequent degradation through carboxylation by many nitrate-reducing, phototrophic, and obligately aerobic bacteria. Acetone carboxylation leads to acetoacetate, which is subsequently activated to a thioester and degraded via thiolysis. Two different types of acetone carboxylases have been described, which require either 2 or 4 ATP equivalents as an energy supply for the carboxylation reaction. Both enzymes appear to combine acetone enolphosphate with carbonic phosphate to form acetoacetate. A similar but more complex enzyme is known to carboxylate the aromatic ketone acetophenone, a metabolic intermediate in anaerobic ethylbenzene metabolism in denitrifying bacteria, with simultaneous hydrolysis of 2 ATP to 2 ADP. Obligately anaerobic sulfate-reducing bacteria activate acetone to a four-carbon compound as well, but via a different process than bicarbonate- or CO2-dependent carboxylation. The present evidence indicates that either carbon monoxide or a formyl residue is used as a cosubstrate, and that the overall ATP expenditure of this pathway is substantially lower than in the known acetone carboxylase reactions. © 2016 S. Karger AG, Basel.

Comparative in vitro activity of ceftaroline, ceftaroline-avibactam, and other antimicrobial agents against aerobic and anaerobic bacteria cultured from infected diabetic foot wounds.

PubMed

Goldstein, Ellie J C; Citron, Diane M; Merriam, C Vreni; Tyrrell, Kerin L

2013-07-01

Foot infections are the most common infectious complication of diabetes. Moderate to severe diabetic foot infections (DFI) are typically polymicrobial with both aerobic and anaerobic organisms. The role of MRSA in these wounds has become an increasing concern. To determine if the addition of avibactam, a novel non-beta-lactam beta-lactamase inhibitor, to ceftaroline would be more active than ceftaroline alone, we tested 316 aerobic pathogens and 154 anaerobic recovered from patients with moderate to severe DFI, and compared ceftaroline with and without avibactam to other agents. Testing on aerobes was done by broth microdilution and by agar dilution for anaerobes, according to CLSI M11-A8, and M7-A8 standards. Ceftaroline-avibactam MIC90 for all Staphylococcus spp. including MRSA was 0.5 μg/mL, and for enterococci was 1 μg/mL. The MIC90s for enteric Gram-negative rods was 0.125 μg/mL. The addition of avibactam to ceftaroline reduced the ceftaroline MICs for 2 strains of resistant Enterobacter spp. and for 1 strain of Morganella. Against anaerobic Gram-positive cocci ceftaroline-avibactam had an MIC90 0.125 μg/mL and for clostridia 1 μg/mL. Avibactam improved ceftaroline's MIC90s for Bacteroides fragilis from >32 to 2 μg/mL and for Prevotella spp. from >32 to 1 μg/mL. Ceftaroline alone demonstrates excellent in vitro activity against most of the aerobes found in moderate to severe DFI. The addition of avibactam provides an increased spectrum of activity including the beta-lactamase producing Prevotella, Bacteroides fragilis and ceftaroline resistant gram-negative enteric organisms. Copyright © 2013 Elsevier Inc. All rights reserved.

The rec A operon: a novel stress response gene cluster in Bacteroides fragilis

PubMed Central

Nicholson, Samantha A; Smalley, Darren; Smith, C. Jeffrey; Abratt, Valerie R

2014-01-01

Bacteroides fragilis, an opportunistic pathogen of humans, is a leading cause of bacteraemias and anaerobic abscesses which are often treated with metronidazole, a drug which damages DNA. This study investigated the responses of the B. fragilis recA three gene operon to the stress experienced during metronidazole treatment and exposure to reactive oxygen species simulating those generated by the host immune system during infection. A transcriptionally regulated response was observed using quantitative RT-PCR after metronidazole and hydrogen peroxide treatment, with all three genes being upregulated under stress conditions. In vivo and in vitro analysis of the functional role of the second gene of the operon was done using heterologous complementation and protein expression (in Escherichia coli), with subsequent biochemical assay. This gene encoded a functional bacterioferritin co-migratory protein (BCP) which was thiol-specific and had antioxidant properties, including protection of the glutamine synthetase III enzyme. This in vitro data supports the hypothesis that the genes of the operon may be involved in protection of the bacteria from the oxidative burst during tissue invasion and may play a significant role in bacterial survival and metronidazole resistance during treatment of B. fragilis infections. PMID:24703997

Genetic, phenotypic and matrix-assisted laser desorption ionization time-of-flight mass spectrometry-based identification of anaerobic bacteria and determination of their antimicrobial susceptibility at a University Hospital in Japan.

PubMed

Yunoki, Tomoyuki; Matsumura, Yasufumi; Nakano, Satoshi; Kato, Karin; Hotta, Go; Noguchi, Taro; Yamamoto, Masaki; Nagao, Miki; Takakura, Shunji; Ichiyama, Satoshi

2016-05-01

The accuracies of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and the phenotypic method using VITEK 2 were compared to the accuracy of 16S rRNA sequence analysis for the identification of 170 clinically isolated anaerobes. The antimicrobial susceptibility of the isolates was also evaluated. Genetic analysis identified 21 Gram-positive species in 14 genera and 29 Gram-negative species in 11 genera. The most frequently isolated genera were Prevotella spp. (n = 46), Bacteroides spp. (n = 25) and Clostridium spp. (n = 25). MALDI-TOF MS correctly identified more isolates compared with VITEK 2 at the species (80 vs. 58%, respectively; p < 0.01) and genus (85 vs. 71%, respectively; p < 0.01) levels. More than 90% of the isolates of the three major genera identified (Prevotella, Bacteroides, and Clostridium species other than Clostridium difficile) were susceptible to beta-lactam/beta-lactamase inhibitor combinations, carbapenems, metronidazole and chloramphenicol. MALDI-TOF MS provided better identification results than VITEK2. Commonly used anti-anaerobic agents indicated that the isolates of the three most frequently identified anaerobic genera exhibited good antimicrobial susceptibility. Copyright © 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Fermentation of mucin and plant polysaccharides by strains of Bacteroides from the human colon.

PubMed Central

Salyers, A A; Vercellotti, J R; West, S E; Wilkins, T D

1977-01-01

Ten Bacteroides species found in the human colon were surveyed for their ability to ferment mucins and plant polysaccharides ("dietary fiber"). A number of strains fermented mucopolysaccharides (heparin, hyaluronate, and chondroitin sulfate) and ovomucoid. Only 3 of the 188 strains tested fermented beef submaxillary mucin, and none fermented porcine gastric mucin. Many of the Bacteroides strains tested were also able to ferment a variety of plant polysaccharides, including amylose, dextran, pectin, gum tragacanth, gum guar, larch arabinogalactan, alginate, and laminarin. Some plant polysaccharides such as gum arabic, gum karaya, gum ghatti and fucoidan, were not utilized by any of the strains tested. The ability to utilize mucins and plant polysaccharides varied considerably among the Bacteroides species tested. PMID:848954

Extensive Mobilome-Driven Genome Diversification in Mouse Gut-Associated Bacteroides vulgatus mpk.

PubMed

Lange, Anna; Beier, Sina; Steimle, Alex; Autenrieth, Ingo B; Huson, Daniel H; Frick, Julia-Stefanie

2016-04-25

Like many other Bacteroides species, Bacteroides vulgatus strain mpk, a mouse fecal isolate which was shown to promote intestinal homeostasis, utilizes a variety of mobile elements for genome evolution. Based on sequences collected by Pacific Biosciences SMRT sequencing technology, we discuss the challenges of assembling and studying a bacterial genome of high plasticity. Additionally, we conducted comparative genomics comparing this commensal strain with the B. vulgatus type strain ATCC 8482 as well as multiple other Bacteroides and Parabacteroides strains to reveal the most important differences and identify the unique features of B. vulgatus mpk. The genome of B. vulgatus mpk harbors a large and diverse set of mobile element proteins compared with other sequenced Bacteroides strains. We found evidence of a number of different horizontal gene transfer events and a genome landscape that has been extensively altered by different mobilization events. A CRISPR/Cas system could be identified that provides a possible mechanism for preventing the integration of invading external DNA. We propose that the high genome plasticity and the introduced genome instabilities of B. vulgatus mpk arising from the various mobilization events might play an important role not only in its adaptation to the challenging intestinal environment in general, but also in its ability to interact with the gut microbiota. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Cephalosporinases associated with outer membrane vesicles released by Bacteroides spp. protect gut pathogens and commensals against β-lactam antibiotics.

PubMed

Stentz, Régis; Horn, Nikki; Cross, Kathryn; Salt, Louise; Brearley, Charles; Livermore, David M; Carding, Simon R

2015-03-01

To identify β-lactamase genes in gut commensal Bacteroides species and to assess the impact of these enzymes, when carried by outer membrane vesicles (OMVs), in protecting enteric pathogens and commensals. A deletion mutant of the putative class A β-lactamase gene (locus tag BT_4507) found in the genome of the human commensal Bacteroides thetaiotaomicron was constructed and a phenotypic analysis performed. A phylogenetic tree was built from an alignment of nine Bacteroides cephalosporinase protein sequences, using the maximum likelihood method. The rate of cefotaxime degradation after incubation with OMVs produced by different Bacteroides species was quantified using a disc susceptibility test. The resistance of Salmonella Typhimurium and Bifidobacterium breve to cefotaxime in liquid culture in the presence of B. thetaiotaomicron OMVs was evaluated by measuring bacterial growth. The B. thetaiotaomicron BT_4507 gene encodes a β-lactamase related to the CepA cephalosporinase of Bacteroides fragilis. OMVs produced by B. thetaiotaomicron and several other Bacteroides species, except Bacteroides ovatus, carried surface-associated β-lactamases that could degrade cefotaxime. β-Lactamase-harbouring OMVs from B. thetaiotaomicron protected Salmonella Typhimurium and B. breve from an otherwise lethal dose of cefotaxime. The production of membrane vesicles carrying surface-associated β-lactamases by Bacteroides species, which constitute a major part of the human colonic microbiota, may protect commensal bacteria and enteric pathogens, such as Salmonella Typhimurium, against β-lactam antibiotics. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.

Complete Genome Sequence of Bacteroides ovatus V975.

PubMed

Wegmann, Udo; Goesmann, Alexander; Carding, Simon R

2016-12-01

The complete genome sequence of Bacteroides ovatus V975 was determined. The genome consists of a single circular chromosome of 6,475,296 bp containing five rRNA operons, 68 tRNA genes, and 4,959 coding genes. Copyright © 2016 Wegmann et al.

Products of Dark CO2 Fixation in Pea Root Nodules Support Bacteroid Metabolism 1

PubMed Central

Rosendahl, Lis; Vance, Carroll P.; Pedersen, Walther B.

1990-01-01

Products of the nodule cytosol in vivo dark [14C]CO2 fixation were detected in the plant cytosol as well as in the bacteroids of pea (Pisum sativum L. cv “Bodil”) nodules. The distribution of the metabolites of the dark CO2 fixation products was compared in effective (fix+) nodules infected by a wild-type Rhizobium leguminosarum (MNF 300), and ineffective (fix−) nodules of the R. leguminosarum mutant MNF 3080. The latter has a defect in the dicarboxylic acid transport system of the bacterial membrane. The 14C incorporation from [14C]CO2 was about threefold greater in the wild-type nodules than in the mutant nodules. Similarly, in wild-type nodules the in vitro phosphoenolpyruvate carboxylase activity was substantially greater than that of the mutant. Almost 90% of the 14C label in the cytosol was found in organic acids in both symbioses. Malate comprised about half of the total cytosol organic acid content on a molar basis, and more than 70% of the cytosol radioactivity in the organic acid fraction was detected in malate in both symbioses. Most of the remaining 14C was contained in the amino acid fraction of the cytosol in both symbioses. More than 70% of the 14C label found in the amino acids of the cytosol was incorporated in aspartate, which on a molar basis comprised only about 1% of the total amino acid pool in the cytosol. The extensive 14C labeling of malate and aspartate from nodule dark [14C]CO2 fixation is consistent with the role of phosphoenolpyruvate carboxlase in nodule dark CO2 fixation. Bacteroids from the effective wild-type symbiosis accumulated sevenfold more 14C than did the dicarboxylic acid transport defective bacteroids. The bacteroids of the effective MNF 300 symbiosis contained the largest proportion of the incorporated 14C in the organic acids, whereas ineffective MNF 3080 bacteroids mainly contained 14C in the amino acid fraction. In both symbioses a larger proportion of the bacteroid 14C label was detected in malate and aspartate

Use of the Hungate anaerobic technique in the isolation of phloroglucinol-negative mutants of Coprococcus species.

PubMed Central

Thompson, L A; Gates, D M; Ingledew, W M; Jones, G A

1976-01-01

The Hungate anaerobic technique was used with a standard procedure for bacterial mutagenesis employing N-methyl-N-nitro-N'-nitrosoguanidine to obtain mutants of an obligate anaerobe. Three mutant strains were derived from a Coprococcus sp., strain Pe15, a rumen anaerobe capable of growing on phloroglucinol. The mutants did not grow on phloroglucinol but did degrade the compound in anaerobic washed-cell suspensions, producing the same end products in approximately the same proportions as the wild type. It was concluded that the mutants were blocked in a unique step or steps necessary for carbon skeleton or energy synthesis from phloroglucinol and not in formation of an enzyme involved in the pathway of phloroglucinol degradation. PMID:782358

Use of the Hungate anaerobic technique in the isolation of phloroglucinol-negative mutants of Coprococcus species.

PubMed

Thompson, L A; Gates, D M; Ingledew, W M; Jones, G A

1976-01-01

The Hungate anaerobic technique was used with a standard procedure for bacterial mutagenesis employing N-methyl-N-nitro-N'-nitrosoguanidine to obtain mutants of an obligate anaerobe. Three mutant strains were derived from a Coprococcus sp., strain Pe15, a rumen anaerobe capable of growing on phloroglucinol. The mutants did not grow on phloroglucinol but did degrade the compound in anaerobic washed-cell suspensions, producing the same end products in approximately the same proportions as the wild type. It was concluded that the mutants were blocked in a unique step or steps necessary for carbon skeleton or energy synthesis from phloroglucinol and not in formation of an enzyme involved in the pathway of phloroglucinol degradation.

Dietary pectic glycans are degraded by coordinated enzyme pathways in human colonic Bacteroides.

PubMed

Luis, Ana S; Briggs, Jonathon; Zhang, Xiaoyang; Farnell, Benjamin; Ndeh, Didier; Labourel, Aurore; Baslé, Arnaud; Cartmell, Alan; Terrapon, Nicolas; Stott, Katherine; Lowe, Elisabeth C; McLean, Richard; Shearer, Kaitlyn; Schückel, Julia; Venditto, Immacolata; Ralet, Marie-Christine; Henrissat, Bernard; Martens, Eric C; Mosimann, Steven C; Abbott, D Wade; Gilbert, Harry J

2018-02-01

The major nutrients available to human colonic Bacteroides species are glycans, exemplified by pectins, a network of covalently linked plant cell wall polysaccharides containing galacturonic acid (GalA). Metabolism of complex carbohydrates by the Bacteroides genus is orchestrated by polysaccharide utilization loci (PULs). In Bacteroides thetaiotaomicron, a human colonic bacterium, the PULs activated by different pectin domains have been identified; however, the mechanism by which these loci contribute to the degradation of these GalA-containing polysaccharides is poorly understood. Here we show that each PUL orchestrates the metabolism of specific pectin molecules, recruiting enzymes from two previously unknown glycoside hydrolase families. The apparatus that depolymerizes the backbone of rhamnogalacturonan-I is particularly complex. This system contains several glycoside hydrolases that trim the remnants of other pectin domains attached to rhamnogalacturonan-I, and nine enzymes that contribute to the degradation of the backbone that makes up a rhamnose-GalA repeating unit. The catalytic properties of the pectin-degrading enzymes are optimized to protect the glycan cues that activate the specific PULs ensuring a continuous supply of inducing molecules throughout growth. The contribution of Bacteroides spp. to metabolism of the pectic network is illustrated by cross-feeding between organisms.

[Effect of indolylacetic acid on formation of bacteroid forms of Rhizobium leguminosarum].

PubMed

Lobanok, E V; Bakanchikova, T I

1979-01-01

The purpose of this work was to study the effect of indolylacetic acid (IAA) on the strains of Rhizobium leguminosarum, effective and noneffective with respect to symbiotic nitrogen fixation (L4 and 245a, and 14--73, respectively). IAA at a concentration of 50 mcg/ml and higher inhibited the growth of the bacterium, temporarily delayed celular division, and induced intensive formation of elongated bacteroid-like cells, predominantly Y-shaped or having a clavate shape. Many bacteroid-like cells were capable of division after a certain delay.

Bacteroides thetaiotaomicron VPI-5482 glycoside hydrolase family 66 homolog catalyzes dextranolytic and cyclization reactions.

PubMed

Kim, Young-Min; Yamamoto, Eiji; Kang, Min-Sun; Nakai, Hiroyuki; Saburi, Wataru; Okuyama, Masayuki; Mori, Haruhide; Funane, Kazumi; Momma, Mitsuru; Fujimoto, Zui; Kobayashi, Mikihiko; Kim, Doman; Kimura, Atsuo

2012-09-01

Bacteroides thetaiotaomicron VPI-5482 harbors a gene encoding a putative cycloisomaltooligosaccharide glucanotransferase (BT3087) belonging to glycoside hydrolase family 66. The goal of the present study was to characterize the catalytic properties of this enzyme. Therefore, we expressed BT3087 (recombinant endo-dextranase from Bacteroides thetaiotaomicron VPI-5482) in Escherichia coli and determined that recombinant endo-dextranase from Bacteroides thetaiotaomicron VPI-5482 preferentially synthesized isomaltotetraose and isomaltooligosaccharides (degree of polymerization > 4) from dextran. The enzyme also generated large cyclic isomaltooligosaccharides early in the reaction. We conclude that members of the glycoside hydrolase 66 family may be classified into three types: (a) endo-dextranases, (b) dextranases possessing weak cycloisomaltooligosaccharide glucanotransferase activity, and (c) cycloisomaltooligosaccharide glucanotransferases. © 2012 The Authors Journal compilation © 2012 FEBS.

A deletion in the chromosome of Bacteroides thetaiotaomicron that abolishes production of chondroitinase II does not affect survival of the organism in gastrointestinal tracts of exgermfree mice.

PubMed Central

Salyers, A A; Guthrie, E P

1988-01-01

Bacteroides thetaiotaomicron, an obligate anaerobe normally found in high concentrations in the human colon, is one of the few colon bacteria that can ferment host mucopolysaccharides such as chondroitin sulfate. Previously, we found that a directed insertional mutation in the gene that codes for the chondroitinase II gene of B. thetaiotaomicron did not affect growth on chondroitin sulfate despite the fact that chondroitinase II accounts for 70% of the total cellular chondroitinase activity. Thus, the chondroitinase II gene did not seem to contribute significantly to growth on chondroitin sulfate when the bacteria were grown in laboratory medium. To determine whether this enzyme is important for bacteria growing in the intestinal tract, we tested the ability of a strain that does not produce chondroitinase II to colonize the intestinal tracts of germfree mice and to compete with wild-type B. thetaiotaomicron. The mutant used in these experiments carried a 0.5-kilobase deletion in the chondroitinase II gene and was constructed so that, unlike the original insertion mutant, it contained no exogenous DNA. The deletion mutant colonized the intestinal tracts of germfree mice at the same levels as the wild type. When a mixture of the deletion mutant and wild type was used to colonize germfree mice, the percent wild type, measured by colony hybridization with the deleted 0.5-kilobase fragment as the hybridization probe, did not rise to 100% even after periods as long as 9 weeks. In most experiments, the percent wild type did not rise significantly above the percent in the original mixture.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:3140726

Decomposition of Alternative Chirality Amino Acids by Alkaliphilic Anaerobe from Owens Lake, California

NASA Technical Reports Server (NTRS)

Townsend, Alisa; Pikuta, Elena V.; Guisler, Melissa; Hoover, Richard B.

2009-01-01

The study of alkaliphilic microbial communities from anaerobic sediments of Owens and Mono Lakes in California led to the isolation of a bacterial strain capable of metabolizing amino acids with alternative chirality. According to the phylogenetic analysis, the anaerobic strain BK1 belongs to the genus Tindallia; however, despite the characteristics of other described species of this genus, the strain BK1 was able to grow on D-arginine and Dlysine. Cell morphology of this strain showed straight, motile, non-spore-forming rods with sizes 0.45 x 1.2-3 microns. Physiological characteristics of the strain showed that it is catalase negative, obligately anaerobic, mesophilic, and obligately alkaliphilic. This isolate is unable to grow at pH 7 and requires CO3 (2-) ions for growth. The strain has chemo-heterotrophic metabolism and is able to ferment various proteolysis products and some sugars. It plays the role of a primary anaerobe within the trophic chain of an anaerobic microbial community by the degradation of complex protein molecules to smaller and less energetic molecules. The new isolate requires NaCl for growth, and can grow within the range of 0.5-13 %, with the optimum at 1 % NaCl (w/v). The temperature range for the growth of the new isolate is 12-40 C with optimum at 35 C. The pH range for the growth of strain BK1 occurs between 7.8 and 11.0 with optimum at 9.5. This paper presents detailed physiological characteristics of the novel isolate from Owens Lake, a unique relic ecosystem of Astrobiological significance, and makes an accent on the ability of this strain to utilize L-amino acids.

Diversity of anaerobic microbes in spacecraft assembly clean rooms.

PubMed

Probst, Alexander; Vaishampayan, Parag; Osman, Shariff; Moissl-Eichinger, Christine; Andersen, Gary L; Venkateswaran, Kasthuri

2010-05-01

Although the cultivable and noncultivable microbial diversity of spacecraft assembly clean rooms has been previously documented using conventional and state-of-the-art molecular techniques, the occurrence of obligate anaerobes within these clean rooms is still uncertain. Therefore, anaerobic bacterial communities of three clean-room facilities were analyzed during assembly of the Mars Science Laboratory rover. Anaerobic bacteria were cultured on several media, and DNA was extracted from suitable anaerobic enrichments and examined with conventional 16S rRNA gene clone library, as well as high-density phylogenetic 16S rRNA gene microarray (PhyloChip) technologies. The culture-dependent analyses predominantly showed the presence of clostridial and propionibacterial strains. The 16S rRNA gene sequences retrieved from clone libraries revealed distinct microbial populations associated with each clean-room facility, clustered exclusively within gram-positive organisms. PhyloChip analysis detected a greater microbial diversity, spanning many phyla of bacteria, and provided a deeper insight into the microbial community structure of the clean-room facilities. This study presents an integrated approach for assessing the anaerobic microbial population within clean-room facilities, using both molecular and cultivation-based analyses. The results reveal that highly diverse anaerobic bacterial populations persist in the clean rooms even after the imposition of rigorous maintenance programs and will pose a challenge to planetary protection implementation activities.

An obligately aerobic soil bacterium activates fermentative hydrogen production to survive reductive stress during hypoxia

PubMed Central

Berney, Michael; Greening, Chris; Conrad, Ralf; Jacobs, William R.; Cook, Gregory M.

2014-01-01

Oxygen availability is a major factor and evolutionary force determining the metabolic strategy of bacteria colonizing an environmental niche. In the soil, conditions can switch rapidly between oxia and anoxia, forcing soil bacteria to remodel their energy metabolism accordingly. Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes. Here we show that an obligate aerobe, the soil actinomycete Mycobacterium smegmatis, adopts an anaerobe-type strategy by activating fermentative hydrogen production to adapt to hypoxia. This process is controlled by the two-component system DosR-DosS/DosT, an oxygen and redox sensor that is well conserved in mycobacteria. We show that DosR tightly regulates the two [NiFe]-hydrogenases: Hyd3 (MSMEG_3931-3928) and Hyd2 (MSMEG_2719-2718). Using genetic manipulation and high-sensitivity GC, we demonstrate that Hyd3 facilitates the evolution of H2 when oxygen is depleted. Combined activity of Hyd2 and Hyd3 was necessary to maintain an optimal NAD+/NADH ratio and enhanced adaptation to and survival of hypoxia. We demonstrate that fermentatively-produced hydrogen can be recycled when fumarate or oxygen become available, suggesting Mycobacterium smegmatis can switch between fermentation, anaerobic respiration, and aerobic respiration. Hydrogen metabolism enables this obligate aerobe to rapidly meet its energetic needs when switching between microoxic and anoxic conditions and provides a competitive advantage in low oxygen environments. PMID:25049411

Amixicile, a novel strategy for targeting oral anaerobic pathogens.

PubMed

Hutcherson, Justin A; Sinclair, Kathryn M; Belvin, Benjamin R; Gui, Qin; Hoffman, Paul S; Lewis, Janina P

2017-09-05

The oral microflora is composed of both health-promoting as well as disease-initiating bacteria. Many of the disease-initiating bacteria are anaerobic and include organisms such as Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Tannerella forsythia. Here we investigated a novel therapeutic, amixicile, that targets pyruvate:ferredoxin oxidoreductase (PFOR), a major metabolic enzyme involved in energy generation through oxidative decarboxylation of pyruvate. PFOR is present in these anaerobic pathogenic bacteria and thus we hypothesized that amixicile would effectively inhibit their growth. In general, PFOR is present in all obligate anaerobic bacteria, while oral commensal aerobes, including aerotolerant ones, such as Streptococcus gordonii, use pyruvate dehydrogenase to decarboxylate pyruvate. Accordingly, we observed that growth of the PFOR-containing anaerobic periodontal pathogens, grown in both monospecies as well as multispecies broth cultures was inhibited in a dose-dependent manner while that of S. gordonii was unaffected. Furthermore, we also show that amixicile is effective against these pathogens grown as monospecies and multispecies biofilms. Finally, amixicile is the first selective therapeutic agent active against bacteria internalized by host cells. Together, the results show that amixicile is an effective inhibitor of oral anaerobic bacteria and as such, is a good candidate for treatment of periodontal diseases.

An in vitro time-kill assessment of linezolid and anaerobic bacteria.

PubMed

Yagi, Betty H; Zurenko, Gary E

2003-02-01

Linezolid is a novel oxazolidinone antibacterial agent active against staphylococci (including methicillin-resistant strains), enterococci (including vancomycin-resistant strains), streptococci (including penicillin-intermediate and -resistant Streptococcus pneumoniae), and other aerobic and facultative bacteria. The agent has also demonstrated activity against a broad spectrum of Gram-positive and Gram-negative anaerobic bacteria. Previous time-kill assessments have shown linezolid to be generally bacteriostatic against staphylococci and enterococci, and bactericidal against streptococci. In this study, an anaerobic glovebox technique was employed to conduct time-kill assessments for four strains of anaerobic Gram-positive, and seven strains of anaerobic Gram-negative bacteria. The time-kill experiment was performed using Anaerobe Broth medium. The drugs were tested at four-fold the minimum inhibitory concentration (MIC), or at the higher concentration of 8mg/L for linezolid, 2mg/L for clindamycin, and 8mg/L for metronidazole. Samples for viable count were taken at 0, 6, and 24h, and plated using the Bioscience International Autospiral DW. Exposure of samples to the aerobic environment during plating was held to less than 30min. Plates were counted after a 48h anaerobic incubation (37 degrees C). The species tested included Bacteroides fragilis (2), B. distasonis, B. thetaiotaomicron, Fusobacterium nucleatum, F. varium, Prevotella melaninogenica, Clostridium perfringens, Eubacterium lentum and Peptostreptococcus anaerobius (2). The activity of linezolid was compared to that of metronidazole and clindamycin, two standard anti-anaerobe agents. As expected, the control agents were very active in these assays. Metronidazole yielded log(10)CFU/mL reductions of 3.0 or greater for nine of ten strains; clindamycin yielded log(10)CFU/mL reductions of 2.0 or greater for six of 11 strains, and 3.0 or greater for three strains. Linezolid also produced significant in vitro

Genomic analysis of Bacteroides fragilis reveals extensive DNA inversions regulating cell surface adaptation

PubMed Central

Kuwahara, Tomomi; Yamashita, Atsushi; Hirakawa, Hideki; Nakayama, Haruyuki; Toh, Hidehiro; Okada, Natsumi; Kuhara, Satoru; Hattori, Masahira; Hayashi, Tetsuya; Ohnishi, Yoshinari

2004-01-01

Bacteroides are predominant human colonic commensals, but the principal pathogenic species, Bacteroides fragilis (BF), lives closely associated with the mucosal surface, whereas a second major species, Bacteroides thetaiotaomicron (BT), concentrates within the colon. We find corresponding differences in their genomes, based on determination of the genome sequence of BF and comparative analysis with BT. Both species have acquired two mechanisms that contribute to their dominance among the colonic microbiota: an exceptional capability to use a wide range of dietary polysaccharides by gene amplification and the capacity to create variable surface antigenicities by multiple DNA inversion systems. However, the gene amplification for polysaccharide assimilation is more developed in BT, in keeping with its internal localization. In contrast, external antigenic structures can be changed more systematically in BF. Thereby, at the mucosal surface, where microbes encounter continuous attack by host defenses, BF evasion of the immune system is favored, and its colonization and infectious potential are increased. PMID:15466707

Promiscuous anaerobes: new and unconventional metabolism in methanogenic archaea.

PubMed

Grochowski, Laura L; White, Robert H

2008-03-01

The development of an oxygenated atmosphere on earth resulted in the polarization of life into two major groups, those that could live in the presence of oxygen and those that could not-the aerobes and the anaerobes. The evolution of aerobes from the earliest anaerobic prokaryotes resulted in a variety of metabolic adaptations. Many of these adaptations center on the need to sustain oxygen-sensitive reactions and cofactors to function in the new oxygen-containing atmosphere. Still other metabolic pathways that were not sensitive to oxygen also diverged. This is likely due to the physical separation of the organisms, based on their ability to live in the presence of oxygen, which allowed for the independent evolution of the pathways. Through the study of metabolic pathways in anaerobes and comparison to the more established pathways from aerobes, insight into metabolic evolution can be gained. This, in turn, can allow for extra- polation to those metabolic pathways occurring in the Last Universal Common Ancestor (LUCA). Some of the unique and uncanonical metabolic pathways that have been identified in the archaea with emphasis on the biochemistry of an obligate anaerobic methanogen, Methanocaldococcus jannaschii are reviewed.

Phenotypic characteristics of nitrate and 3-nitro-1-propionate-respiring enzymes of the obligate respiratory anaerobe Denitrobacterium detoxificans

USDA-ARS?s Scientific Manuscript database

Anaerobic respiration consumes reducing equivalents generated during fermentation thereby contributing to the maintenance of hydrogen homoeostasis in gut ecosystems. Nitrate and 3-nitro-1-propionate (NPA) are acceptors used by the nonfermentative, rumen anaerobe, Denitrobacterium detoxificans, whic...

Anaerobic consumers of monosaccharides in a moderately acidic fen.

PubMed

Hamberger, Alexandra; Horn, Marcus A; Dumont, Marc G; Murrell, J Colin; Drake, Harold L

2008-05-01

16S rRNA-based stable isotope probing identified active xylose- and glucose-fermenting Bacteria and active Archaea, including methanogens, in anoxic slurries of material obtained from a moderately acidic, CH(4)-emitting fen. Xylose and glucose were converted to fatty acids, CO(2), H(2), and CH(4) under moderately acidic, anoxic conditions, indicating that the fen harbors moderately acid-tolerant xylose- and glucose-using fermenters, as well as moderately acid-tolerant methanogens. Organisms of the families Acidaminococcaceae, Aeromonadaceae, Clostridiaceae, Enterobacteriaceae, and Pseudomonadaceae and the order Actinomycetales, including hitherto unknown organisms, utilized xylose- or glucose-derived carbon, suggesting that highly diverse facultative aerobes and obligate anaerobes contribute to the flow of carbon in the fen under anoxic conditions. Uncultured Euryarchaeota (i.e., Methanosarcinaceae and Methanobacteriaceae) and Crenarchaeota species were identified by 16S rRNA analysis of anoxic slurries, demonstrating that the acidic fen harbors novel methanogens and Crenarchaeota organisms capable of anaerobiosis. Fermentation-derived molecules are conceived to be the primary drivers of methanogenesis when electron acceptors other than CO(2) are absent, and the collective findings of this study indicate that fen soils harbor diverse, acid-tolerant, and novel xylose-utilizing as well as glucose-utilizing facultative aerobes and obligate anaerobes that form trophic links to novel moderately acid-tolerant methanogens.

Anaerobic Catabolism of Aromatic Compounds: a Genetic and Genomic View

PubMed Central

Carmona, Manuel; Zamarro, María Teresa; Blázquez, Blas; Durante-Rodríguez, Gonzalo; Juárez, Javier F.; Valderrama, J. Andrés; Barragán, María J. L.; García, José Luis; Díaz, Eduardo

2009-01-01

Summary: Aromatic compounds belong to one of the most widely distributed classes of organic compounds in nature, and a significant number of xenobiotics belong to this family of compounds. Since many habitats containing large amounts of aromatic compounds are often anoxic, the anaerobic catabolism of aromatic compounds by microorganisms becomes crucial in biogeochemical cycles and in the sustainable development of the biosphere. The mineralization of aromatic compounds by facultative or obligate anaerobic bacteria can be coupled to anaerobic respiration with a variety of electron acceptors as well as to fermentation and anoxygenic photosynthesis. Since the redox potential of the electron-accepting system dictates the degradative strategy, there is wide biochemical diversity among anaerobic aromatic degraders. However, the genetic determinants of all these processes and the mechanisms involved in their regulation are much less studied. This review focuses on the recent findings that standard molecular biology approaches together with new high-throughput technologies (e.g., genome sequencing, transcriptomics, proteomics, and metagenomics) have provided regarding the genetics, regulation, ecophysiology, and evolution of anaerobic aromatic degradation pathways. These studies revealed that the anaerobic catabolism of aromatic compounds is more diverse and widespread than previously thought, and the complex metabolic and stress programs associated with the use of aromatic compounds under anaerobic conditions are starting to be unraveled. Anaerobic biotransformation processes based on unprecedented enzymes and pathways with novel metabolic capabilities, as well as the design of novel regulatory circuits and catabolic networks of great biotechnological potential in synthetic biology, are now feasible to approach. PMID:19258534

Suppression of bactericidal activity of human polymorphonuclear leukocytes by Bacteroides gingivalis.

PubMed Central

Yoneda, M; Maeda, K; Aono, M

1990-01-01

The direct effects of the culture supernatant of oral microorganisms on the bactericidal activity of human polymorphonuclear leukocytes (PMNs) were investigated. The bactericidal activity of PMNs, which were preincubated with the supernatant of Bacteroides gingivalis, Bacteroides intermedius, Bacteroides melaninogenicus or phosphate-buffered saline, was examined by counting the surviving bacteria. B. gingivalis-treated PMNs were found to have a diminished ability for killing bacteria in the presence or absence of serum. The chemiluminescence response of PMNs, which were preincubated with the culture supernatant of B. gingivalis, was strikingly reduced compared with that of PMNs preincubated with phosphate-buffered saline or other bacterial culture supernatants. The production of superoxide anion (O2-) by PMNs stimulated with either formyl-methionyl-leucyl-phenylalanine or phorbol myristate acetate was reduced in both cases after the PMNs were preincubated with the culture supernatant of B. gingivalis. However, it was observed that there was more reduction in superoxide anion (O2-) production stimulated with formyl-methionyl-leucyl-phenylalanine compared with that stimulated with phorbol myristate acetate. These results suggest that B. gingivalis releases a factor which interferes with the bactericidal activity of PMNs by modulating the generation of reactive oxygen species. These suppressive effects on bactericidal activity may be important in the pathogenesis of this microorganism. PMID:2153632

Unusual sub-genus associations of faecal Prevotella and Bacteroides with specific dietary patterns.

PubMed

De Filippis, Francesca; Pellegrini, Nicoletta; Laghi, Luca; Gobbetti, Marco; Ercolini, Danilo

2016-10-21

Diet has a recognized effect in shaping gut microbiota. Many studies link an increase in Prevotella to high-fibre diet, while Bacteroides abundance is usually associated with the consumption of animal fat and protein-rich diets. Nevertheless, closely related species and strains may harbour different genetic pools; therefore, further studies should aim to understand whether species of the same genus are consistently linked to dietary patterns or equally responsive to diet variations. Here, we used oligotyping of 16S rRNA gene sequencing data to exploit the diversity within Prevotella and Bacteroides genera in faecal samples of omnivore and non-omnivore subjects from a previously studied cohort. A great heterogeneity was found in oligotype composition. Nevertheless, different oligotypes within the same genus showed distinctive correlation patterns with dietary components and metabolome. We found that some Prevotella oligotypes are significantly associated with the plant-based diet but some are associated with animal-based nutrients, and the same applies to Bacteroides. Therefore, an indiscriminate association of Bacteroidetes genera with specific dietary patterns may lead to an oversimplified vision that does not take into account sub-genus diversity and the different possible responses to dietary components. We demonstrated that Prevotella and Bacteroides oligotypes show distinctive correlation patterns with dietary components and metabolome. These results substantiate a current oversimplification of diet-dependent microbe-host associations and highlighted that sub-genus differences must be taken into account when planning gut microbiota modulation for health benefits.

[Detection of anaerobic processes and microorganisms in immobilized activated sludge of a wastewater treatment plant with intense aeration].

PubMed

Litti, Iu V; Nekrasova, V K; Kulikov, N I; Siman'kova, M V; Nozhevnikova, A N

2013-01-01

Attached activated sludge from the Krasnaya Polyana (Sochi) wastewater treatment plant was studied after the reconstruction by increased aeration and water recycle, as well as by the installation of a bristle carrier for activated sludge immobilization. The activated sludge biofilms developing under conditions of intense aeration were shown to contain both aerobic and anaerobic microorganisms. Activity of a strictly anaerobic methanogenic community was revealed, which degraded organic compounds to methane, further oxidized by aerobic methanotrophs. Volatile fatty acids, the intermediates of anaerobic degradation of complex organic compounds, were used by both aerobic and anaerobic microorganisms. Anaerobic oxidation of ammonium with nitrite (anammox) and the presence of obligate anammox bacteria were revealed in attached activated sludge biofilms. Simultaneous aerobic and anaerobic degradation of organic contaminants by attached activated sludge provides for high rates of water treatment, stability of the activated sludge under variable environmental conditions, and decreased excess sludge formation.

Next-generation RNA-based fluorescent biosensors enable anaerobic detection of cyclic di-GMP

PubMed Central

Wang, Xin C.; Wilson, Stephen C.; Hammond, Ming C.

2016-01-01

Bacteria occupy a diverse set of environmental niches with differing oxygen availability. Anaerobic environments such as mammalian digestive tracts and industrial reactors harbor an abundance of both obligate and facultative anaerobes, many of which play significant roles in human health and biomanufacturing. Studying bacterial function under partial or fully anaerobic conditions, however, is challenging given the paucity of suitable live-cell imaging tools. Here, we introduce a series of RNA-based fluorescent biosensors that respond selectively to cyclic di-GMP, an intracellular bacterial second messenger that controls cellular motility and biofilm formation. We demonstrate the utility of these biosensors in vivo under both aerobic and anaerobic conditions, and we show that biosensor expression does not interfere with the native motility phenotype. Together, our results attest to the effectiveness and versatility of RNA-based fluorescent biosensors, priming further development and application of these and other analogous sensors to study host–microbial and microbial–microbial interactions through small molecule signals. PMID:27382070

In Vitro Evaluation of the Activity of Imipenem-Relebactam against 451 Recent Clinical Isolates of Bacteroides Group and Related Species

PubMed Central

Jacobus, Nilda V.; McDermott, Laura A.

2016-01-01

We evaluated the in vitro activity of imipenem-relebactam (imipenem-MK7655) against 451 recent clinical isolates within the Bacteroides group and related species. Relebactam did not enhance or inhibit the activity of imipenem against Bacteroides fragilis or other Bacteroides species. No synergistic or antagonistic effect was observed. The MICs of imipenem-relebactam were equal to or within one dilution of the MICs of these isolates to imipenem. PMID:27480858

Nitric oxide is an obligate bacterial nitrification intermediate produced by hydroxylamine oxidoreductase.

PubMed

Caranto, Jonathan D; Lancaster, Kyle M

2017-08-01

Ammonia (NH 3 )-oxidizing bacteria (AOB) emit substantial amounts of nitric oxide (NO) and nitrous oxide (N 2 O), both of which contribute to the harmful environmental side effects of large-scale agriculture. The currently accepted model for AOB metabolism involves NH 3 oxidation to nitrite (NO 2 - ) via a single obligate intermediate, hydroxylamine (NH 2 OH). Within this model, the multiheme enzyme hydroxylamine oxidoreductase (HAO) catalyzes the four-electron oxidation of NH 2 OH to NO 2 - We provide evidence that HAO oxidizes NH 2 OH by only three electrons to NO under both anaerobic and aerobic conditions. NO 2 - observed in HAO activity assays is a nonenzymatic product resulting from the oxidation of NO by O 2 under aerobic conditions. Our present study implies that aerobic NH 3 oxidation by AOB occurs via two obligate intermediates, NH 2 OH and NO, necessitating a mediator of the third enzymatic step.

Induction of vascular endothelial growth factor expression in human pulp fibroblasts stimulated with black-pigmented Bacteroides.

PubMed

Yang, L-C; Tsai, C-H; Huang, F-M; Su, Y-F; Lai, C-C; Liu, C-M; Chang, Y-C

2004-09-01

To investigate the effect of black-pigmented Bacteroides on the expression of vascular endothelial growth factor (VEGF) gene in human pulp fibroblasts. The supernatants of Porphyromonas endodontalis, Porphyromonas gingivalis and Prevotella intermedia were used to evaluate VEGF gene expression in human pulp fibroblasts. The levels of mRNAs were measured by the quantitative reverse-transcriptase polymerase chain reaction analysis. Black-pigmented Bacteroides induced significantly high levels of VEGF mRNA gene expression in human pulp fibroblasts (P < 0.05). In addition, the expression of VEGF depended on the bacteria tested. Black-pigmented Bacteroides may be involved in developing pulpal disease through the stimulation of VEGF production that would lead to the expansion of the vascular network coincident to progression of the inflammation.

Rapid QPCR-based assay for fecal Bacteroides spp. as a tool for assessing fecal contamination in recreational waters.

PubMed

Converse, Reagan R; Blackwood, A Denene; Kirs, Marek; Griffith, John F; Noble, Rachel T

2009-11-01

Concentrations of fecal indicator bacteria (FIB; e.g. Escherichia coli, and Enterococcus sp.) can only be used in limited ways for determining the source of fecal contamination in recreational waters because they cannot distinguish human from non-human fecal contamination. Several Bacteroides spp. have been suggested as potential alternative indicators. We have developed a rapid, culture-independent method for quantifying fecal Bacteroides spp. using quantitative PCR (QPCR) targeting the 16S rRNA gene. The assay specifically targets and quantifies the most common human Bacteroides spp. The details of the method are presented, including analyses of a wide range of fecal samples from different organisms. Specificity and performance of the QPCR assay were also tested via a laboratory experiment where human sewage and gull guano were inoculated into a range of environmental water samples. Concentrations of fecal Bacteroides spp., total Enterococcus sp., Enterococcus faecium, Enterococcus faecalis, and Enterococcus casseliflavus were measured using QPCR, and total Enterococcus sp. and E. coli were quantified by membrane filtration (MF). Samples spiked with gull guano were highly concentrated with total Enterococcus sp., E. coli, E. faecalis, and E. casseliflavus, demonstrating that these indicators are prominent in animal feces. On the other hand, fecal Bacteroides spp. concentrations were high in samples containing sewage and were relatively low in samples spiked with gull guano. Sensitivity and specificity results suggest that the rapid fecal Bacteroides spp. QPCR assay may be a useful tool to effectively predict the presence and concentration of human-specific fecal pollution.

Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms ▿ †

PubMed Central

Probst, Alexander; Vaishampayan, Parag; Osman, Shariff; Moissl-Eichinger, Christine; Andersen, Gary L.; Venkateswaran, Kasthuri

2010-01-01

Although the cultivable and noncultivable microbial diversity of spacecraft assembly clean rooms has been previously documented using conventional and state-of-the-art molecular techniques, the occurrence of obligate anaerobes within these clean rooms is still uncertain. Therefore, anaerobic bacterial communities of three clean-room facilities were analyzed during assembly of the Mars Science Laboratory rover. Anaerobic bacteria were cultured on several media, and DNA was extracted from suitable anaerobic enrichments and examined with conventional 16S rRNA gene clone library, as well as high-density phylogenetic 16S rRNA gene microarray (PhyloChip) technologies. The culture-dependent analyses predominantly showed the presence of clostridial and propionibacterial strains. The 16S rRNA gene sequences retrieved from clone libraries revealed distinct microbial populations associated with each clean-room facility, clustered exclusively within gram-positive organisms. PhyloChip analysis detected a greater microbial diversity, spanning many phyla of bacteria, and provided a deeper insight into the microbial community structure of the clean-room facilities. This study presents an integrated approach for assessing the anaerobic microbial population within clean-room facilities, using both molecular and cultivation-based analyses. The results reveal that highly diverse anaerobic bacterial populations persist in the clean rooms even after the imposition of rigorous maintenance programs and will pose a challenge to planetary protection implementation activities. PMID:20228115

Ecophysiological consequences of alcoholism on human gut microbiota: implications for ethanol-related pathogenesis of colon cancer.

PubMed

Tsuruya, Atsuki; Kuwahara, Akika; Saito, Yuta; Yamaguchi, Haruhiko; Tsubo, Takahisa; Suga, Shogo; Inai, Makoto; Aoki, Yuichi; Takahashi, Seiji; Tsutsumi, Eri; Suwa, Yoshihide; Morita, Hidetoshi; Kinoshita, Kenji; Totsuka, Yukari; Suda, Wataru; Oshima, Kenshiro; Hattori, Masahira; Mizukami, Takeshi; Yokoyama, Akira; Shimoyama, Takefumi; Nakayama, Toru

2016-06-13

Chronic consumption of excess ethanol increases the risk of colorectal cancer. The pathogenesis of ethanol-related colorectal cancer (ER-CRC) is thought to be partly mediated by gut microbes. Specifically, bacteria in the colon and rectum convert ethanol to acetaldehyde (AcH), which is carcinogenic. However, the effects of chronic ethanol consumption on the human gut microbiome are poorly understood, and the role of gut microbes in the proposed AcH-mediated pathogenesis of ER-CRC remains to be elaborated. Here we analyse and compare the gut microbiota structures of non-alcoholics and alcoholics. The gut microbiotas of alcoholics were diminished in dominant obligate anaerobes (e.g., Bacteroides and Ruminococcus) and enriched in Streptococcus and other minor species. This alteration might be exacerbated by habitual smoking. These observations could at least partly be explained by the susceptibility of obligate anaerobes to reactive oxygen species, which are increased by chronic exposure of the gut mucosa to ethanol. The AcH productivity from ethanol was much lower in the faeces of alcoholic patients than in faeces of non-alcoholic subjects. The faecal phenotype of the alcoholics could be rationalised based on their gut microbiota structures and the ability of gut bacteria to accumulate AcH from ethanol.

Differential Decay of Human Faecal Bacteroides in Marine and Freshwater

EPA Science Inventory

Gene sequences from Bacteroides and relatives are being considered for the enumeration of aquatic fecal contamination and estimation of public health risk. To interpret these data, it is necessary to understand the decay of molecular and cultivated indicators and pathogens in en...

Isolation and characterization of Bacteroides host strain HB-73 used to detect sewage specific phages in Hawaii.

PubMed

Vijayavel, Kannappan; Fujioka, Roger; Ebdon, James; Taylor, Huw

2010-06-01

Previous studies have shown that Escherichia coli and enterococci are unreliable indicators of fecal contamination in Hawaii because of their ability to multiply in environmental soils. In this study, the method of detecting Bacteroides phages as specific markers of sewage contamination in Hawaii's recreational waters was evaluated because these sewage specific phages cannot multiply under environmental conditions. Bacteroides hosts (GB-124, GA-17), were recovered from sewage samples in Europe and were reported to be effective in detecting phages from sewage samples obtained in certain geographical areas. However, GB-124 and GA-17 hosts were ineffective in detecting phages from sewage samples obtained in Hawaii. Bacteroides host HB-73 was isolated from a sewage sample in Hawaii, confirmed as a Bacteroides sp. and shown to recover phages from multiple sources of sewage produced in Hawaii at high concentrations (5.2-7.3 x 10(5) PFU/100 mL). These Bacteroides phages were considered as potential markers of sewage because they also survived for three days in fresh stream water and two days in marine water. Water samples from Hawaii's coastal swimming beaches and harbors, which were known to be contaminated with discharges from streams, were shown to contain moderate (20-187 CFU/100 mL) to elevated (173-816 CFU/100 mL) concentrations of enterococci. These same samples contained undetectable levels (<10 PFU/100 mL) of F+ coliphage and Bacteroides phages and provided evidence to suggest that these enterococci may not necessarily be associated with the presence of raw sewage. These results support previous conclusions that discharges from streams are the major sources of enterococci in coastal waters of Hawaii and the most likely source of these enterococci is from environmental soil rather than from sewage. 2010 Elsevier Ltd. All rights reserved.

Bacteroides (Parabacteroides) distasonis splenic abscess in a sickle cell patient.

PubMed

Al-Tawfiq, Jaffar A

2008-01-01

Splenic abscess is not an uncommon complication of patients with sickle-cell disease. Here we describe an 18 year-old boy with sickle cell disease and left upper quadrant abdominal pain. Computerized axial tomography revealed left sided free flowing pleural effusion and splenomegaly with liquefaction and possible gas formation. The splenic fluid grew an unusual organism known as Bacteroides distasonis. The patient received antimicrobial therapy and underwent a splenectomy with full recovery. The spleen was cystically infarcted and measured 22 x 16 x 5 cm. The capsule was thickened and covered by fibrinous exudate. Histopathologic examination of the spleen showed complete necrosis with reparative fibrosis. This case presents an unusual cause of splenic abscess due to Bacteroides distasonis with a subacute to chronic course. The presence of fever and left sided pleuritic chest pain in patients with sickle cell disease should raise the suspicion of splenic abscess.

Arsenic, Anaerobes, and Autotrophy.

NASA Astrophysics Data System (ADS)

Oremland, R. S.

2008-12-01

That microbes have resistance to the toxic arsenic oxyanions arsenite [As(III)] and arsenate [As(V)] has been recognized for some time. More recently it was shown that certain prokaryotes can demonstrate As- dependent growth by conserving the energy gained from the aerobic oxidation of As(III) to As(V), or from the reduction of As(V) to As(III) under anaerobic conditions. During the course of our field studies of two alkaline, hypersaline soda lakes (Mono Lake and Searles Lake, CA) we have discovered several new anaerobic chemo- and photo-autotrophic bacteria that can center their energy gain around the redox reactions between As(III) and As(V). Alkalilimnicola ehrlichii, isolated from the water column of Mono Lake is a nitrate-respiring, As(III)-oxidizing chemoautotroph of the gamma-proteobacteria that has a highly flexible metabolism. It can function either as a facultative anaerobe or as a chemo-autotroph, or as a heterotroph (Hoeft et al., 2007). In contrast, strain MLMS-1 of the delta-proteobacteria was also isolated from Mono Lake, but to date is the first example of an obligate As(V)-respirer that is also an obligate chemo-autotroph, gaining its energy via the oxidation of sulfide to sulfate (Hoeft et al., 2004). Strain SLAS-1, isolated from salt-saturated Searles Lake is a member of the Halananerobiales, and can either grow as a heterotroph (lactate e-donor) or chemo- autotroph (sulfide e-donor) while respiring As(V). The fact that it can achieve this feat at salt-saturation (~ 340 g/L) makes it a true extremophile (Oremland et. al., 2005). Finally, strain PHS-1 isolated from a hot spring on Paoha island in Mono Lake is the first example of a photosynthetic bacterium of the gamma- proteobacteria able to link its growth to As(III)-dependent anoxygenic photosynthesis (Kulp et al., 2008). These novel microbes give us new insights into the evolution of arsenic-based metabolism and their role in the biogeochemical cycling of this toxic element. Hoeft, S.E., et

In Vitro Evaluation of the Activity of Imipenem-Relebactam against 451 Recent Clinical Isolates of Bacteroides Group and Related Species.

PubMed

Snydman, David R; Jacobus, Nilda V; McDermott, Laura A

2016-10-01

We evaluated the in vitro activity of imipenem-relebactam (imipenem-MK7655) against 451 recent clinical isolates within the Bacteroides group and related species. Relebactam did not enhance or inhibit the activity of imipenem against Bacteroides fragilis or other Bacteroides species. No synergistic or antagonistic effect was observed. The MICs of imipenem-relebactam were equal to or within one dilution of the MICs of these isolates to imipenem. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Obliging children.

PubMed

Lyons, Barry

2011-01-01

Children may sometimes undergo healthcare procedures that are not intended to improve their health status. Such interventions might include the use of young children as bone marrow donors or their enrolment in non-therapeutic research. One of the justifications used to legitimise these interventions is the premise that children have obligations to others; to their family in the case of related bone marrow transplantation, and to wider society in the case of non-therapeutic research. However, this 'obligation model' (the notion that children possess positive obligations to advance the health status of others) fails as a justificatory paradigm because it is based upon a confusion, identified by Hart, between two notions; that of 'being under an obligation to do something' and that of 'being obliged to do something'. Instead the 'obligation model' is a device employed to put a justificatory gloss upon a consequentialist decision-making process; removing the legitimising gloss allows for a more transparent look at the conflict between parental rights and an individual child's right to bodily integrity.

Identification of anaerobic selenate-respiring bacteria from aquatic sediments.

PubMed

Narasingarao, Priya; Häggblom, Max M

2007-06-01

The diversity population of microorganisms with the capability to use selenate as a terminal electron acceptor, reducing it to selenite and elemental selenium by the process known as dissimilatory selenate reduction, is largely unknown. The overall objective of this study was to gain an in-depth understanding of anaerobic biotransformation of selenium in the environment, particularly anaerobic respiration, and to characterize the microorganisms catalyzing this process. Here, we demonstrate the isolation and characterization of four novel anaerobic dissimilatory selenate-respiring bacteria enriched from a variety of sources, including sediments from three different water bodies in Chennai, India, and a tidal estuary in New Jersey. Strains S5 and S7 from India, strain KM from the Meadowlands, NJ, and strain pn1, categorized as a laboratory contaminant, were all phylogenetically distinct, belonging to various phyla in the bacterial domain. The 16S rRNA gene sequence shows that strain S5 constitutes a new genus belonging to Chrysiogenetes, while strain S7 belongs to the Deferribacteres, with greater than 98% 16S rRNA gene similarity to Geovibrio ferrireducens. Strain KM is related to Malonomonas rubra, Pelobacter acidigallici, and Desulfuromusa spp., with 96 to 97% 16S rRNA gene similarity. Strain pn1 is 99% similar to Pseudomonas stutzeri. Strains S5, S7, and KM are obligately anaerobic selenate-respiring microorganisms, while strain pn1 is facultatively anaerobic. Besides respiring selenate, all these strains also respire nitrate.

The relationship between nitrogen fixation and the production of HD from D2 by cell-free extracts of soya-bean nodule bacteroids

PubMed Central

Turner, G. L.; Bergersen, F. J.

1969-01-01

1. Cell-free extracts prepared from soya-bean nodule bacteroids produced HD from D2 in the presence of dithionite, an ATP-generating system and nitrogen. 2. Crude extracts of bacteroids or of Azotobacter vinelandii showed some background D2 exchange when any one of these was omitted. 3. Partial purification of bacteroid extracts diminished this background activity and gave increased D2 exchange and nitrogen fixation. 4. Although increasing pN2 stimulated both reactions, the apparent Km (N2) for nitrogen fixation was much higher than the apparent Km (N2) for D2 exchange when partially purified bacteroid extracts were used. 5. Carbon monoxide was a competitive inhibitor of nitrogen fixation by partially purified bacteroid extracts, but D2 exchange was inhibited in a non-competitive fashion. 6. These results are discussed in relation to the possible existence of enzyme-bound intermediates of nitrogen fixation. PMID:5353527

Sequential changes in luminal microflora and mucosal cytokine expression during developing of colitis in HLA-B27/beta2-microglobulin transgenic rats.

PubMed

Hata, K; Andoh, A; Sato, H; Araki, Y; Tanaka, M; Tsujikawa, T; Fujiyama, Y; Bamba, T

2001-11-01

Transgenic rats expressing HLA-B27 and human beta2-microglobulin (HLA-B27 rats) spontaneously develop chronic colitis resembling human inflammatory bowel disease. We investigated the sequential changes in the luminal bacterial flora and mucosal cytokine mRNA expression in this model. HLA-B27 rats were maintained in a specific pathogen-free environment, and luminal microflora was evaluated by standard bacterial culture technique. The expression of mucosal cytokine mRNA was analysed by RT-PCR methods. Clinical symptoms of colitis appeared at 8 weeks of age. The total number of obligate anaerobes was higher than those of facultative anaerobes during the experimental period. At 6 weeks of age, the colonization of Bacteroides spp., Bifidobacterium spp. and Lactobacillus spp. was already detectable at high concentrations, whereas Clostridium spp. and Eubacterium spp. were not detected. The expression of proinflammatory cytokines (IL-Ibeta, IL-8 and TNF-alpha) appeared at 8 weeks of age, and these were detectable until 17 weeks. A similar pattern was observed in the expression of Th1 cytokines (IL-2, IL-12 and IFN-gamma). On the other hand, the expression of Th2 cytokines (IL-4, IL-10 and TGF-beta) was weak. IL-4 mRNA expression was weakly detectable only at 6 and 8 weeks of age. The expression of IL-10 and TGF-beta mRNA was scarcely detectable throughout the experimental period. The development of colitis may be mediated by both the predominant expression of Th1 cytokines and the weakness of Th2 cytokine expression in the mucosa. The colonization of anaerobic bacteria, especially Bacteroides spp., may be initiating and promoting these cytokine responses.

Redesigning Escherichia coli Metabolism for Anaerobic Production of Isobutanol▿†

PubMed Central

Trinh, Cong T.; Li, Johnny; Blanch, Harvey W.; Clark, Douglas S.

2011-01-01

Fermentation enables the production of reduced metabolites, such as the biofuels ethanol and butanol, from fermentable sugars. This work demonstrates a general approach for designing and constructing a production host that uses a heterologous pathway as an obligately fermentative pathway to produce reduced metabolites, specifically, the biofuel isobutanol. Elementary mode analysis was applied to design an Escherichia coli strain optimized for isobutanol production under strictly anaerobic conditions. The central metabolism of E. coli was decomposed into 38,219 functional, unique, and elementary modes (EMs). The model predictions revealed that during anaerobic growth E. coli cannot produce isobutanol as the sole fermentative product. By deleting 7 chromosomal genes, the total 38,219 EMs were constrained to 12 EMs, 6 of which can produce high yields of isobutanol in a range from 0.29 to 0.41 g isobutanol/g glucose under anaerobic conditions. The remaining 6 EMs rely primarily on the pyruvate dehydrogenase enzyme complex (PDHC) and are typically inhibited under anaerobic conditions. The redesigned E. coli strain was constrained to employ the anaerobic isobutanol pathways through deletion of 7 chromosomal genes, addition of 2 heterologous genes, and overexpression of 5 genes. Here we present the design, construction, and characterization of an isobutanol-producing E. coli strain to illustrate the approach. The model predictions are evaluated in relation to experimental data and strategies proposed to improve anaerobic isobutanol production. We also show that the endogenous alcohol/aldehyde dehydrogenase AdhE is the key enzyme responsible for the production of isobutanol and ethanol under anaerobic conditions. The glycolytic flux can be controlled to regulate the ratio of isobutanol to ethanol production. PMID:21642415

A Novel Tightly Regulated Gene Expression System for the Human Intestinal Symbiont Bacteroides thetaiotaomicron.

PubMed

Horn, Nikki; Carvalho, Ana L; Overweg, Karin; Wegmann, Udo; Carding, Simon R; Stentz, Régis

2016-01-01

There is considerable interest in studying the function of Bacteroides species resident in the human gastrointestinal (GI)-tract and the contribution they make to host health. Reverse genetics and protein expression techniques, such as those developed for well-characterized Escherichia coli cannot be applied to Bacteroides species as they and other members of the Bacteriodetes phylum have unique promoter structures. The availability of useful Bacteroides-specific genetic tools is therefore limited. Here we describe the development of an effective mannan-controlled gene expression system for Bacteroides thetaiotaomicron containing the mannan-inducible promoter-region of an α-1,2-mannosidase gene (BT_3784), a ribosomal binding site designed to modulate expression, a multiple cloning site to facilitate the cloning of genes of interest, and a transcriptional terminator. Using the Lactobacillus pepI as a reporter gene, mannan induction resulted in an increase of reporter activity in a time- and concentration-dependent manner with a wide range of activity. The endogenous BtcepA cephalosporinase gene was used to demonstrate the suitability of this novel expression system, enabling the isolation of a His-tagged version of BtCepA. We have also shown with experiments performed in mice that the system can be induced in vivo in the presence of an exogenous source of mannan. By enabling the controlled expression of endogenous and exogenous genes in B. thetaiotaomicron this novel inducer-dependent expression system will aid in defining the physiological role of individual genes and the functional analyses of their products.

A Novel Tightly Regulated Gene Expression System for the Human Intestinal Symbiont Bacteroides thetaiotaomicron

PubMed Central

Horn, Nikki; Carvalho, Ana L.; Overweg, Karin; Wegmann, Udo; Carding, Simon R.; Stentz, Régis

2016-01-01

There is considerable interest in studying the function of Bacteroides species resident in the human gastrointestinal (GI)-tract and the contribution they make to host health. Reverse genetics and protein expression techniques, such as those developed for well-characterized Escherichia coli cannot be applied to Bacteroides species as they and other members of the Bacteriodetes phylum have unique promoter structures. The availability of useful Bacteroides-specific genetic tools is therefore limited. Here we describe the development of an effective mannan-controlled gene expression system for Bacteroides thetaiotaomicron containing the mannan-inducible promoter–region of an α-1,2-mannosidase gene (BT_3784), a ribosomal binding site designed to modulate expression, a multiple cloning site to facilitate the cloning of genes of interest, and a transcriptional terminator. Using the Lactobacillus pepI as a reporter gene, mannan induction resulted in an increase of reporter activity in a time- and concentration-dependent manner with a wide range of activity. The endogenous BtcepA cephalosporinase gene was used to demonstrate the suitability of this novel expression system, enabling the isolation of a His-tagged version of BtCepA. We have also shown with experiments performed in mice that the system can be induced in vivo in the presence of an exogenous source of mannan. By enabling the controlled expression of endogenous and exogenous genes in B. thetaiotaomicron this novel inducer-dependent expression system will aid in defining the physiological role of individual genes and the functional analyses of their products. PMID:27468280

Bacteriophages infecting Bacteroides as a marker for microbial source tracking.

PubMed

Jofre, Joan; Blanch, Anicet R; Lucena, Francisco; Muniesa, Maite

2014-05-15

Bacteriophages infecting certain strains of Bacteroides are amid the numerous procedures proposed for tracking the source of faecal pollution. These bacteriophages fulfil reasonably well most of the requirements identified as appropriate for a suitable marker of faecal sources. Thus, different host strains are available that detect bacteriophages preferably in water contaminated with faecal wastes corresponding to different animal species. For phages found preferably in human faecal wastes, which are the ones that have been more extensively studied, the amounts of phages found in waters contaminated with human fecal samples is reasonably high; these amounts are invariable through the time; their resistance to natural and anthropogenic stressors is comparable to that of other relatively resistant indicator of faecal pollution such us coliphages; the abundance ratios of somatic coliphages and bacteriophages infecting Bacteroides thetaiotaomicron GA17 are unvarying in recent and aged contamination; and standardised detection methods exist. These methods are easy, cost effective and provide data susceptible of numerical analysis. In contrast, there are some uncertainties regarding their geographical stability, and consequently suitable hosts need to be isolated for different geographical areas. However, a feasible method has been described to isolate suitable hosts in a given geographical area. In summary, phages infecting Bacteroides are a marker of faecal sources that in our opinion merits being included in the "toolbox" for microbial source tracking. However, further research is still needed in order to make clear some uncertainties regarding some of their characteristics and behaviour, to compare their suitability to the one of emerging methods such us targeting Bacteroidetes by qPCR assays; or settling molecular methods for their determination. Copyright © 2014 Elsevier Ltd. All rights reserved.

The ecology of anaerobic degraders of BTEX hydrocarbons in aquifers

PubMed Central

Lueders, Tillmann

2017-01-01

Abstract The degradation of benzene, toluene, ethylbenzene and xylene (BTEX) contaminants in groundwater relies largely on anaerobic processes. While the physiology and biochemistry of selected relevant microbes have been intensively studied, research has now started to take the generated knowledge back to the field, in order to trace the populations truly responsible for the anaerobic degradation of BTEX hydrocarbons in situ and to unravel their ecology in contaminated aquifers. Here, recent advances in our knowledge of the identity, diversity and ecology of microbes involved in these important ecosystem services are discussed. At several sites, distinct lineages within the Desulfobulbaceae, the Rhodocyclaceae and the Gram-positive Peptococcaceae have been shown to dominate the degradation of different BTEX hydrocarbons. Especially for the functional guild of anaerobic toluene degraders, specific molecular detection systems have been developed, allowing researchers to trace their diversity and distribution in contaminated aquifers. Their populations appear enriched in hot spots of biodegradation in situ. 13C-labelling experiments have revealed unexpected pathways of carbon sharing and obligate syntrophic interactions to be relevant in degradation. Together with feedback mechanisms between abiotic and biotic habitat components, this promotes an enhanced ecological perspective of the anaerobic degradation of BTEX hydrocarbons, as well as its incorporation into updated concepts for site monitoring and bioremediation. PMID:27810873

Aerobic and anaerobic bacteriology of adenoids in children: a comparison between patients with chronic adenotonsillitis and adenoid hypertrophy.

PubMed

Brook, I

1981-03-01

Adenoids were obtained from 18 children with chronic adenotonsillitis (Group A) and from 12 others with adenoid hypertrophy (Group B). Patients' ages ranged from 20 months to 15 years (mean 6 years); 18 were males and 12 females. The adenoids were sectioned in half after heat searing of the surface, and the core material was cultured for aerobic and anaerobic microorganisms. Mixed aerobic and anaerobic flora were obtained from all patients, yielding an average of 7.8 isolates (4.6 anaerobes and 3.2 aerobes) per specimen. There were 97 anaerobes isolated. The predominant isolates in both groups were: Bacteroides sp. (including B. melaninogenicus and B. oralis), Fusobacterium sp., gram-positive anaerobic cocci, and Veillonella sp. There were 138 aerobic isolates. The predominant isolates in both groups were: alpha and gamma hemolytic streptococci, beta hemolytic streptococci (Group A, B, C, and F), S. aureus, S. pneumoniae, and Hemophilus sp. Hemophilus influenzae type B, and S. aureus were more frequently isolated in Group A. B. fragilis was only recovered in Group A. Beta lactamase production was noted in 27 isolates obtained from 18 patients. Fifteen of these patients belonged to Group A (83% of Group A), while 3 were members of Group B (25% of Group B). These bacteria were all isolates of S. aureus (11) and B. fragilis (2), 8 of 22 B. melaninogenicus group, 4 of 11 B. oralis, and two of 8 H. influenza type B. Our findings indicate the polymicrobial nature of deep adenoid flora and demonstrate the presence of many beta lactamase-producing organisms in children with recurrent adenotonsillitis.

Bovine Intestinal Bacteria Inactivate and Degrade Ceftiofur and Ceftriaxone with Multiple β-Lactamases▿

PubMed Central

Wagner, R. Doug; Johnson, Shemedia J.; Cerniglia, Carl E.; Erickson, Bruce D.

2011-01-01

The veterinary cephalosporin drug ceftiofur is rapidly degraded in the bovine intestinal tract. A cylinder-plate assay was used to detect microbiologically active ceftiofur, and high-performance liquid chromatography-mass spectrometry analysis was used to quantify the amount of ceftiofur remaining after incubation with bovine intestinal anaerobic bacteria, which were isolated from colon contents or feces from 8 cattle. Ninety-six percent of the isolates were able to inactivate ceftiofur to some degree, and 54% actually degraded the drug. None of 9 fungal isolates inactivated or degraded ceftiofur. Facultative and obligate anaerobic bacterial species that inactivated or degraded ceftiofur were identified with Vitek and Biolog systems, respectively. A subset of ceftiofur degraders also degraded the chemically similar drug ceftriaxone. Most of the species of bacteria that degraded ceftiofur belonged to the genera Bacillus and Bacteroides. PCR analysis of bacterial DNA detected specific β-lactamase genes. Bacillus cereus and B. mycoides isolates produced extended-spectrum β-lactamases and metallo-β-lactamases. Seven isolates of Bacteroides spp. produced multiple β-lactamases, including possibly CepA, and metallo-β-lactamases. Isolates of Eubacterium biforme, Bifidobacterium breve, and several Clostridium spp. also produced ceftiofur-degrading β-lactamases. An agar gel overlay technique on isoelectric focusing separations of bacterial lysates showed that β-lactamase enzymes were sufficient to degrade ceftiofur. These results suggest that ceftiofur is inactivated nonenzymatically and degraded enzymatically by multiple β-lactamases from bacteria in the large intestines of cattle. PMID:21876048

Bovine intestinal bacteria inactivate and degrade ceftiofur and ceftriaxone with multiple beta-lactamases.

PubMed

Wagner, R Doug; Johnson, Shemedia J; Cerniglia, Carl E; Erickson, Bruce D

2011-11-01

The veterinary cephalosporin drug ceftiofur is rapidly degraded in the bovine intestinal tract. A cylinder-plate assay was used to detect microbiologically active ceftiofur, and high-performance liquid chromatography-mass spectrometry analysis was used to quantify the amount of ceftiofur remaining after incubation with bovine intestinal anaerobic bacteria, which were isolated from colon contents or feces from 8 cattle. Ninety-six percent of the isolates were able to inactivate ceftiofur to some degree, and 54% actually degraded the drug. None of 9 fungal isolates inactivated or degraded ceftiofur. Facultative and obligate anaerobic bacterial species that inactivated or degraded ceftiofur were identified with Vitek and Biolog systems, respectively. A subset of ceftiofur degraders also degraded the chemically similar drug ceftriaxone. Most of the species of bacteria that degraded ceftiofur belonged to the genera Bacillus and Bacteroides. PCR analysis of bacterial DNA detected specific β-lactamase genes. Bacillus cereus and B. mycoides isolates produced extended-spectrum β-lactamases and metallo-β-lactamases. Seven isolates of Bacteroides spp. produced multiple β-lactamases, including possibly CepA, and metallo-β-lactamases. Isolates of Eubacterium biforme, Bifidobacterium breve, and several Clostridium spp. also produced ceftiofur-degrading β-lactamases. An agar gel overlay technique on isoelectric focusing separations of bacterial lysates showed that β-lactamase enzymes were sufficient to degrade ceftiofur. These results suggest that ceftiofur is inactivated nonenzymatically and degraded enzymatically by multiple β-lactamases from bacteria in the large intestines of cattle.

Deep sequencing-based analysis of the anaerobic stimulon in Neisseria gonorrhoeae

PubMed Central

2011-01-01

Background Maintenance of an anaerobic denitrification system in the obligate human pathogen, Neisseria gonorrhoeae, suggests that an anaerobic lifestyle may be important during the course of infection. Furthermore, mounting evidence suggests that reduction of host-produced nitric oxide has several immunomodulary effects on the host. However, at this point there have been no studies analyzing the complete gonococcal transcriptome response to anaerobiosis. Here we performed deep sequencing to compare the gonococcal transcriptomes of aerobically and anaerobically grown cells. Using the information derived from this sequencing, we discuss the implications of the robust transcriptional response to anaerobic growth. Results We determined that 198 chromosomal genes were differentially expressed (~10% of the genome) in response to anaerobic conditions. We also observed a large induction of genes encoded within the cryptic plasmid, pJD1. Validation of RNA-seq data using translational-lacZ fusions or RT-PCR demonstrated the RNA-seq results to be very reproducible. Surprisingly, many genes of prophage origin were induced anaerobically, as well as several transcriptional regulators previously unknown to be involved in anaerobic growth. We also confirmed expression and regulation of a small RNA, likely a functional equivalent of fnrS in the Enterobacteriaceae family. We also determined that many genes found to be responsive to anaerobiosis have also been shown to be responsive to iron and/or oxidative stress. Conclusions Gonococci will be subject to many forms of environmental stress, including oxygen-limitation, during the course of infection. Here we determined that the anaerobic stimulon in gonococci was larger than previous studies would suggest. Many new targets for future research have been uncovered, and the results derived from this study may have helped to elucidate factors or mechanisms of virulence that may have otherwise been overlooked. PMID:21251255

Characterization of a Methanogenic Community within an Algal Fed Anaerobic Digester

PubMed Central

Ellis, Joshua T.; Tramp, Cody; Sims, Ronald C.; Miller, Charles D.

2012-01-01

The microbial diversity and metabolic potential of a methanogenic consortium residing in a 3785-liter anaerobic digester, fed with wastewater algae, was analyzed using 454 pyrosequencing technology. DNA was extracted from anaerobic sludge material and used in metagenomic analysis through PCR amplification of the methyl-coenzyme M reductase α subunit (mcrA) gene using primer sets ML, MCR, and ME. The majority of annotated mcrA sequences were assigned taxonomically to the genera Methanosaeta in the order Methanosarcinales. Methanogens from the genus Methanosaeta are obligate acetotrophs, suggesting this genus plays a dominant role in methane production from the analyzed fermentation sample. Numerous analyzed sequences within the algae fed anaerobic digester were unclassified and could not be assigned taxonomically. Relative amplicon frequencies were determined for each primer set to determine the utility of each in pyrosequencing. Primer sets ML and MCR performed better quantitatively (representing the large majority of analyzed sequences) than primer set ME. However, each of these primer sets was shown to provide a quantitatively unique community structure, and thus they are of equal importance in mcrA metagenomic analysis. PMID:23724331

Fiber-utilizing capacity varies in Prevotella- versus Bacteroides-dominated gut microbiota.

PubMed

Chen, Tingting; Long, Wenmin; Zhang, Chenhong; Liu, Shuang; Zhao, Liping; Hamaker, Bruce R

2017-06-01

The gut microbiota of individuals are dominated by different fiber-utilizing bacteria, which ferment dietary fiber into short chain fatty acids (SCFAs) known to be important for human health. Here, we show that the dominance of Prevotella versus Bacteroides in fecal innocula, identified into two different enterotypes, differentially impacts in vitro fermentation profiles of SCFAs from fibers with different chemical structures. In a microbiome of the Prevotella enterotype, fructooligosaccharides, and sorghum and corn arabinoxylans significantly promoted one single Prevotella OTU with equally high production of total SCFAs with propionate as the major product. Conversely, in the Bacteroides-dominated microbiota, the three fibers enriched different OTUs leading to different levels and ratios of SCFAs. This is the first report showing how individual differences in two enterotypes cause distinctly different responses to dietary fiber. Microbiota dominated by different fiber-utilizing bacteria may impact host health by way of producing different amounts and profiles of SCFAs from the same carbohydrate substrates.

Antimicrobial Activity of Endodontic Medicaments and Vehicles using Agar Well Diffusion Method on Facultative and Obligate Anaerobes

PubMed Central

Bhat, Kishore G; Sogi, Suma

2016-01-01

, and lesser chances of developing resistance. How to cite this article Nalawade TM, Bhat KG, Sogi S. Antimicrobial Activity of Endodontic Medicaments and Vehicles using Agar Well Diffusion Method on Facultative and Obligate Anaerobes. Int J Clin Pediatr Dent 2016;9(4):335-341. PMID:28127166

The ecology of anaerobic degraders of BTEX hydrocarbons in aquifers.

PubMed

Lueders, Tillmann

2017-01-01

The degradation of benzene, toluene, ethylbenzene and xylene (BTEX) contaminants in groundwater relies largely on anaerobic processes. While the physiology and biochemistry of selected relevant microbes have been intensively studied, research has now started to take the generated knowledge back to the field, in order to trace the populations truly responsible for the anaerobic degradation of BTEX hydrocarbons in situ and to unravel their ecology in contaminated aquifers. Here, recent advances in our knowledge of the identity, diversity and ecology of microbes involved in these important ecosystem services are discussed. At several sites, distinct lineages within the Desulfobulbaceae, the Rhodocyclaceae and the Gram-positive Peptococcaceae have been shown to dominate the degradation of different BTEX hydrocarbons. Especially for the functional guild of anaerobic toluene degraders, specific molecular detection systems have been developed, allowing researchers to trace their diversity and distribution in contaminated aquifers. Their populations appear enriched in hot spots of biodegradation in situ 13 C-labelling experiments have revealed unexpected pathways of carbon sharing and obligate syntrophic interactions to be relevant in degradation. Together with feedback mechanisms between abiotic and biotic habitat components, this promotes an enhanced ecological perspective of the anaerobic degradation of BTEX hydrocarbons, as well as its incorporation into updated concepts for site monitoring and bioremediation. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A new chromogenic medium for isolation of Bacteroides fragilis suitable for screening for strains with antimicrobial resistance.

PubMed

Tierney, Daniel; Copsey, Sarah D; Morris, Trefor; Perry, John D

2016-06-01

There have been an increasing number of reports describing the acquisition of antimicrobial resistance by Bacteroides fragilis including the occurrence of strains with resistance to multiple antimicrobials that are relied upon for treatment of infections. The aim of this study was to design a chromogenic selective medium for isolation of B. fragilis that could be adapted for specific isolation of antimicrobial-resistant strains. Bacteroides chromogenic agar (BCA) was the result of this endeavour and allowed growth of Bacteroides spp. as black colonies and the efficient inhibition of almost all other genera tested. The medium also allowed some differentiation of B. fragilis from other members of the B. fragilis group. When compared with an adaptation of Bacteroides bile-esculin agar (BBE) for the isolation of B. fragilis from 100 stool samples, 30 isolates of B. fragilis were recovered on BCA compared with 19 isolates recovered on BBE (P = 0.022). When supplemented with meropenem (4 μg/ml) or metronidazole (2 μg/ml), BCA could be used to select for the growth of B. fragilis isolates with resistance to these agents. We conclude that BCA is a useful research tool for surveillance studies to assess the prevalence of B. fragilis and, in particular, the occurrence of antimicrobial-resistant strains. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anaerobic biosynthesis of the lower ligand of vitamin B12

PubMed Central

Hazra, Amrita B.; Han, Andrew W.; Mehta, Angad P.; Mok, Kenny C.; Osadchiy, Vadim; Begley, Tadhg P.; Taga, Michiko E.

2015-01-01

Vitamin B12 (cobalamin) is required by humans and other organisms for diverse metabolic processes, although only a subset of prokaryotes is capable of synthesizing B12 and other cobamide cofactors. The complete aerobic and anaerobic pathways for the de novo biosynthesis of B12 are known, with the exception of the steps leading to the anaerobic biosynthesis of the lower ligand, 5,6-dimethylbenzimidazole (DMB). Here, we report the identification and characterization of the complete pathway for anaerobic DMB biosynthesis. This pathway, identified in the obligate anaerobic bacterium Eubacterium limosum, is composed of five previously uncharacterized genes, bzaABCDE, that together direct DMB production when expressed in anaerobically cultured Escherichia coli. Expression of different combinations of the bza genes revealed that 5-hydroxybenzimidazole, 5-methoxybenzimidazole, and 5-methoxy-6-methylbenzimidazole, all of which are lower ligands of cobamides produced by other organisms, are intermediates in the pathway. The bza gene content of several bacterial and archaeal genomes is consistent with experimentally determined structures of the benzimidazoles produced by these organisms, indicating that these genes can be used to predict cobamide structure. The identification of the bza genes thus represents the last remaining unknown component of the biosynthetic pathway for not only B12 itself, but also for three other cobamide lower ligands whose biosynthesis was previously unknown. Given the importance of cobamides in environmental, industrial, and human-associated microbial metabolism, the ability to predict cobamide structure may lead to an improved ability to understand and manipulate microbial metabolism. PMID:26246619

Strong antimicrobial activity of xanthohumol and other derivatives from hops (Humulus lupulus L.) on gut anaerobic bacteria.

PubMed

Cermak, Pavel; Olsovska, Jana; Mikyska, Alexandr; Dusek, Martin; Kadleckova, Zuzana; Vanicek, Jiri; Nyc, Otakar; Sigler, Karel; Bostikova, Vanda; Bostik, Pavel

2017-11-01

Anaerobic bacteria, such as Bacteroides fragilis or Clostridium perfringens, are part of indigenous human flora. However, Clostridium difficile represents also an important causative agent of nosocomial infectious antibiotic-associated diarrhoea. Treatment of C. difficile infection is problematic, making it imperative to search for new compounds with antimicrobial properties. Hops (Humulus lupulus L.) contain substances with antibacterial properties. We tested antimicrobial activity of purified hop constituents humulone, lupulone and xanthohumol against anaerobic bacteria. The antimicrobial activity was established against B. fragilis, C. perfringens and C. difficile strains according to standard testing protocols (CLSI, EUCAST), and the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBC) were calculated. All C. difficile strains were toxigenic and clinically relevant, as they were isolated from patients with diarrhoea. Strongest antimicrobial effects were observed with xanthohumol showing MIC and MBC values of 15-107 μg/mL, which are close to those of conventional antibiotics in the strains of bacteria with increased resistance. Slightly higher MIC and MBC values were obtained with lupulone followed by higher values of humulone. Our study, thus, shows a potential of purified hop compounds, especially xanthohumol, as alternatives for treatment of infections caused by select anaerobic bacteria, namely nosocomial diarrhoea caused by resistant strains. © 2017 APMIS. Published by John Wiley & Sons Ltd.

Estimation of the Relative Abundance of Different Bacteroides and Prevotella Ribotypes in Gut Samples by Restriction Enzyme Profiling of PCR-Amplified 16S rRNA Gene Sequences

PubMed Central

Wood, Jacqueline; Scott, Karen P.; Avguštin, Gorazd; Newbold, C. James; Flint, Harry J.

1998-01-01

We describe an approach for determining the genetic composition of Bacteroides and Prevotella populations in gut contents based on selective amplification of 16S rRNA gene sequences (rDNA) followed by cleavage of the amplified material with restriction enzymes. The relative contributions of different ribotypes to total Bacteroides and Prevotella 16S rDNA are estimated after end labelling of one of the PCR primers, and the contribution of Bacteroides and Prevotella sequences to total eubacterial 16S rDNA is estimated by measuring the binding of oligonucleotide probes to amplified DNA. Bacteroides and Prevotella 16S rDNA accounted for between 12 and 62% of total eubacterial 16S rDNA in samples of ruminal contents from six sheep and a cow. Ribotypes 4, 5, 6, and 7, which include most cultivated rumen Prevotella strains, together accounted for between 20 and 86% of the total amplified Bacteroides and Prevotella rDNA in these samples. The most abundant Bacteroides or Prevotella ribotype in four animals, however, was ribotype 8, for which there is only one known cultured isolate, while ribotypes 1 and 2, which include many colonic Bacteroides spp., were the most abundant in two animals. This indicates that some abundant Bacteroides and Prevotella groups in the rumen are underrepresented among cultured rumen Prevotella isolates. The approach described here provides a rapid, convenient, and widely applicable method for comparing the genotypic composition of bacterial populations in gut samples. PMID:9758785

Bacteroides induce higher IgA production than Lactobacillus by increasing activation-induced cytidine deaminase expression in B cells in murine Peyer's patches.

PubMed

Yanagibashi, Tsutomu; Hosono, Akira; Oyama, Akihito; Tsuda, Masato; Hachimura, Satoshi; Takahashi, Yoshimasa; Itoh, Kikuji; Hirayama, Kazuhiro; Takahashi, Kyoko; Kaminogawa, Shuichi

2009-02-01

The gut mucosal immune system is crucial in host defense against infection by pathogenic microbacteria and viruses via the production of IgA. Previous studies have shown that intestinal commensal bacteria enhance mucosal IgA production. However, it is poorly understood how these bacteria induce IgA production and which genera of intestinal commensal bacteria induce IgA production effectively. In this study, we compared the immunomodulatory effects of Bacteroides and Lactobacillus on IgA production by Peyer's patches lymphocytes. IgA production by Peyer's patches lymphocytes co-cultured with Bacteroides was higher than with Lactobacillus. In addition, the expression of activation-induced cytidine deaminase increased in co-culture with Bacteroides but not with Lactobacillus. We found that intestinal commensal bacteria elicited IgA production. In particular, Bacteroides induced the differentiation of Peyer's patches B cell into IgA(+) B cells by increasing activation-induced cytidine deaminase expression.

Cross-inhibition between black-pigmented Bacteroides species.

PubMed

Van Winkelhoff, A J; Kippuw, N; De Graaff, J

1987-11-01

Cross-inhibition within the group of black-pigmented Bacteroides, including both oral and non-oral strains, was studied by means of a membrane filter technique. It was found that B. gingivalis possessed the most extended inhibitory capacity among all species tested. B. gingivalis showed inhibitory activity against B. intermedius, B. endodontalis, B. loescheii, and B. melaninogenicus. B. endodontalis was active against some B. intermedius strains. Among the saccharolytic species, some B. melaninogenicus strains were inhibitory for some B. endodontalis strains, some B. gingivalis strains, and some B. intermedius strains. These inhibitory activities observed in vitro may play a role in the colonization of the periodontal pocket.

Specificity of a Bacteroides thetaiotaomicron marker for human feces

USGS Publications Warehouse

Carson, C.A.; Christiansen, J.M.; Yampara-Iquise, H.; Benson, V.W.; Baffaut, C.; Davis, J.V.; Broz, R.R.; Kurtz, W.B.; Rogers, W.M.; Fales, W.H.

2005-01-01

A bacterial primer set, known to produce a 542-bp amplicon specific for Bacteroides thetaiotaomicron, generated this product in PCR with 1 ng of extracted DNA from 92% of 25 human fecal samples, 100% of 20 sewage samples, and 16% of 31 dog fecal samples. The marker was not detected in 1 ng of fecal DNA from 61 cows, 35 horses, 44 pigs, 24 chickens, 29 turkeys, and 17 geese. Copyright ?? 2005, American Society for Microbiology. All Rights Reserved.

Bacteroides in the infant gut consume milk oligosaccharides via mucus-utilization pathways.

PubMed

Marcobal, Angela; Barboza, Mariana; Sonnenburg, Erica D; Pudlo, Nicholas; Martens, Eric C; Desai, Prerak; Lebrilla, Carlito B; Weimer, Bart C; Mills, David A; German, J Bruce; Sonnenburg, Justin L

2011-11-17

Newborns are colonized with an intestinal microbiota shortly after birth, but the factors governing the retention and abundance of specific microbial lineages are unknown. Nursing infants consume human milk oligosaccharides (HMOs) that pass undigested to the distal gut, where they may be digested by microbes. We determined that the prominent neonate gut residents, Bacteroides thetaiotaomicron and Bacteroides fragilis, induce the same genes during HMO consumption that are used to harvest host mucus glycans, which are structurally similar to HMOs. Lacto-N-neotetraose, a specific HMO component, selects for HMO-adapted species such as Bifidobacterium infantis, which cannot use mucus, and provides a selective advantage to B. infantis in vivo when biassociated with B. thetaiotaomicron in the gnotobiotic mouse gut. This indicates that the complex oligosaccharide mixture within HMOs attracts both mutualistic mucus-adapted species and HMO-adapted bifidobacteria to the infant intestine that likely facilitate both milk and future solid food digestion. Copyright © 2011 Elsevier Inc. All rights reserved.

Bacteroides in the Infant Gut Consume Milk Oligosaccharides via Mucus-Utilization Pathways

PubMed Central

Marcobal, A.; Barboza, M.; Sonnenburg, E.D.; Pudlo, N.; Martens, E.C.; Desai, P.; Lebrilla, C.B.; Weimer, B.C.; Mills, D.A.; German, J.B.; Sonnenburg, J.L.

2011-01-01

Summary Newborns are colonized with an intestinal microbiota shortly after birth but the factors governing the retention and abundance of specific microbial lineages are unknown. Nursing infants consume human milk oligosaccharides (HMOs) that pass undigested to the distal gut where they may be digested by microbes. We determined that the prominent neonate gut residents, Bacteroides thetaiotaomicron and Bacteroides fragilis, induce the same genes during HMO consumption that are used to harvest host mucus glycans, which are structurally similar to HMOs. Lacto-N-neotetraose, a specific HMO component, selects for HMO-adapted species such as Bifidobacterium infantis, which cannot use mucus, and provides a selective advantage to B. infantis in vivo when bi-associated with B. thetaiotaomicron in the gnotobiotic mouse gut. This indicates that the complex oligosaccharide mixture within HMOs attracts both mutualistic mucus-adapted species and HMO-adapted bifidobacteria to the infant intestine that likely facilitate both milk and future solid food digestion. PMID:22036470

Explicit hypoxia targeting with tumor suppression by creating an “obligate” anaerobic Salmonella Typhimurium strain

PubMed Central

Yu, Bin; Yang, Mei; Shi, Lei; Yao, Yandan; Jiang, Qinqin; Li, Xuefei; Tang, Lei-Han; Zheng, Bo-Jian; Yuen, Kwok-Yung; Smith, David K.; Song, Erwei; Huang, Jian-Dong

2012-01-01

Using bacteria as therapeutic agents against solid tumors is emerging as an area of great potential in the treatment of cancer. Obligate and facultative anaerobic bacteria have been shown to infiltrate the hypoxic regions of solid tumors, thereby reducing their growth rate or causing regression. However, a major challenge for bacterial therapy of cancer with facultative anaerobes is avoiding damage to normal tissues. Consequently the virulence of bacteria must be adequately attenuated for therapeutic use. By placing an essential gene under a hypoxia conditioned promoter, Salmonella Typhimurium strain SL7207 was engineered to survive only in anaerobic conditions (strain YB1) without otherwise affecting its functions. In breast tumor bearing nude mice, YB1 grew within the tumor, retarding its growth, while being rapidly eliminated from normal tissues. YB1 provides a safe bacterial vector for anti-tumor therapies without compromising the other functions or tumor fitness of the bacterium as attenuation methods normally do. PMID:22666539

A survey of culturable aerobic and anaerobic marine bacteria in de novo biofilm formation on natural substrates in St. Andrews Bay, Scotland.

PubMed

Finnegan, Lucy; Garcia-Melgares, Manuel; Gmerek, Tomasz; Huddleston, W Ryan; Palmer, Alexander; Robertson, Andrew; Shapiro, Sarah; Unkles, Shiela E

2011-10-01

This study reports a novel study of marine biofilm formation comprising aerobic and anaerobic bacteria. Samples of quartz and feldspar, minerals commonly found on the earth, were suspended 5 m deep in the North Sea off the east coast of St. Andrews, Scotland for 5 weeks. The assemblage of organisms attached to these stones was cultivated under aerobic and anaerobic conditions in the laboratory. Bacteria isolated on Marine Agar 2216 were all Gram-negative and identified to genus level by sequencing the gene encoding 16S rRNA. Colwellia, Maribacter, Pseudoaltermonas and Shewanella were observed in aerobically-grown cultures while Vibrio was found to be present in both aerobic and anaerobic cultures. The obligate anaerobic bacterium Psychrilyobacter atlanticus, a recently defined genus, was identified as a close relative of isolates grown anaerobically. The results provide valuable information as to the main players that attach and form de novo biofilms on common minerals in sea water.

Characterization of the Bacteroides fragilis bfr Gene Product Identifies a Bacterial DPS-Like Protein and Suggests Evolutionary Links in the Ferritin Superfamily

PubMed Central

Gauss, George H.; Reott, Michael A.; Rocha, Edson R.; Young, Mark J.; Douglas, Trevor

2012-01-01

A factor contributing to the pathogenicity of Bacteroides fragilis, the most common anaerobic species isolated from clinical infections, is the bacterium's extreme aerotolerance, which allows survival in oxygenated tissues prior to anaerobic abscess formation. We investigated the role of the bacterioferritin-related (bfr) gene in the B. fragilis oxidative stress response. The bfr mRNA levels are increased in stationary phase or in response to O2 or iron. In addition, bfr null mutants exhibit reduced aerotolerance, and the bfr gene product protects DNA from hydroxyl radical cleavage in vitro. Crystallographic studies revealed a protein with a dodecameric structure and greater similarity to an archaeal DNA protection in starved cells (DPS)-like protein than to the 24-subunit bacterioferritins. Similarity to the DPS-like (DPSL) protein extends to the subunit and includes a pair of conserved cysteine residues juxtaposed to a buried dimetal binding site within the four-helix bundle. Compared to archaeal DPSLs, however, this bacterial DPSL protein contains several unique features, including a significantly different conformation in the C-terminal tail that alters the number and location of pores leading to the central cavity and a conserved metal binding site on the interior surface of the dodecamer. Combined, these characteristics confirm this new class of miniferritin in the bacterial domain, delineate the similarities and differences between bacterial DPSL proteins and their archaeal homologs, allow corrected annotations for B. fragilis bfr and other dpsl genes within the bacterial domain, and suggest an evolutionary link within the ferritin superfamily that connects dodecameric DPS to the (bacterio)ferritin 24-mer. PMID:22020642

Hydrophobicities of human polymorphonuclear leukocytes and oral Bacteroides and Porphyromonas spp., Wolinella recta, and Eubacterium yurii with special reference to bacterial surface structures.

PubMed

Haapasalo, M; Kerosuo, E; Lounatmaa, K

1990-12-01

The hydrophobicities of human polymorphonuclear leukocytes (PMNLs) and Bacteroides buccae, B. oris, B. oralis, B. veroralis, B. buccalis, B. heparinolyticus, B. intermedius, B. denticola, B. loescheii, B. melaninogenicus, Porphyromonas gingivalis, P. endodontalis, Wolinella recta, and Eubacterium yurii were studied by the hexadecane method. The majority of the strains were equally or less hydrophobic than the PMNLs. Only in the case of E. yurii and the only strain of B. buccalis were all strains more hydrophobic than the PMNLs. However, some strains of B. intermedius, B. oris, B. denticola, and P. gingivalis were also more hydrophobic than the PMNLs. With the exception of B. intermedius and species with a crystalline surface protein layer (S-layer), the strains of all other species with a thick capsule were more hydrophilic than the strains with little or no extracellular polymeric material. All strains of the S-layer species were either quite hydrophilic or hydrophobic depending on the species, totally irrespective of the presence of the capsule. The results suggest that the S-layers of oral anaerobic bacteria may be important determinants of cell surface hydrophobicity.

Live Faecalibacterium prausnitzii Does Not Enhance Epithelial Barrier Integrity in an Apical Anaerobic Co-Culture Model of the Large Intestine.

PubMed

Maier, Eva; Anderson, Rachel C; Roy, Nicole C

2017-12-12

Appropriate intestinal barrier maturation during infancy largely depends on colonization with commensal bacteria. Faecalibacterium prausnitzii is an abundant obligate anaerobe that colonizes during weaning and is thought to maintain colonic health throughout life. We previously showed that F. prausnitzii induced Toll-like receptor 2 (TLR2) activation, which is linked to enhanced tight junction formation. Therefore, we hypothesized that F. prausnitzii enhances barrier integrity, an important factor in appropriate intestinal barrier maturation. In order to test metabolically active bacteria, we used a novel apical anaerobic co-culture system that allows the survival of both obligate anaerobic bacteria and oxygen-requiring intestinal epithelial cells (Caco-2). The first aim was to optimize the culture medium to enable growth and active metabolism of F. prausnitzii while maintaining the viability and barrier integrity, as measured by trans-epithelial electrical resistance (TEER), of the Caco-2 cells. This was achieved by supplementing the apical cell culture medium with bacterial culture medium. The second aim was to test the effect of F. prausnitzii on TEER across Caco-2 cell layers. Live F. prausnitzii did not improve TEER, which indicates that its benefits are not via altering tight junction integrity. The optimization of the novel dual-environment co-culturing system performed in this research will enable the investigation of new probiotics originating from indigenous beneficial bacteria.

Live Faecalibacterium prausnitzii Does Not Enhance Epithelial Barrier Integrity in an Apical Anaerobic Co-Culture Model of the Large Intestine

PubMed Central

Maier, Eva; Anderson, Rachel C.; Roy, Nicole C.

2017-01-01

Appropriate intestinal barrier maturation during infancy largely depends on colonization with commensal bacteria. Faecalibacterium prausnitzii is an abundant obligate anaerobe that colonizes during weaning and is thought to maintain colonic health throughout life. We previously showed that F. prausnitzii induced Toll-like receptor 2 (TLR2) activation, which is linked to enhanced tight junction formation. Therefore, we hypothesized that F. prausnitzii enhances barrier integrity, an important factor in appropriate intestinal barrier maturation. In order to test metabolically active bacteria, we used a novel apical anaerobic co-culture system that allows the survival of both obligate anaerobic bacteria and oxygen-requiring intestinal epithelial cells (Caco-2). The first aim was to optimize the culture medium to enable growth and active metabolism of F. prausnitzii while maintaining the viability and barrier integrity, as measured by trans-epithelial electrical resistance (TEER), of the Caco-2 cells. This was achieved by supplementing the apical cell culture medium with bacterial culture medium. The second aim was to test the effect of F. prausnitzii on TEER across Caco-2 cell layers. Live F. prausnitzii did not improve TEER, which indicates that its benefits are not via altering tight junction integrity. The optimization of the novel dual-environment co-culturing system performed in this research will enable the investigation of new probiotics originating from indigenous beneficial bacteria. PMID:29231875

In vitro activities of ramoplanin, teicoplanin, vancomycin, linezolid, bacitracin, and four other antimicrobials against intestinal anaerobic bacteria.

PubMed

Citron, D M; Merriam, C V; Tyrrell, K L; Warren, Y A; Fernandez, H; Goldstein, E J C

2003-07-01

By using an agar dilution method, the in vitro activities of ramoplanin, teicoplanin, vancomycin, linezolid, and five other agents were determined against 300 gram-positive and 54 gram-negative strains of intestinal anaerobes. Ramoplanin was active at Bacteroides fragilis group, the Fusobacterium mortiferum-Fusobacterium varium group, and Veillonella spp. were >or=256 microg/ml. Ramoplanin displays excellent activity against C. difficile and other gram-positive enteric anaerobes, including vancomycin-resistant strains; however, it has poor activity against most gram-negative anaerobes and thus potentially has a lesser effect on the ecological balance of normal fecal flora.

[Modifying action of oxytocin on the biological properties of the causative agents of anaerobic non-clostridial infection].

PubMed

Abramzon, O M; Kirillov, D A; Pan'kov, A S; Perunova, N B; Elagina, N N; Valyshev, A V; Bukharin, O V

2003-01-01

In a number of in vitro experiments the effect of oxytocin on the antilysozyme and anticomplemental activity of Propiobacterium propionicum, Bacteroides fragilis, Prevotella melaninogenica and Peptostreprtococcus anaerobius, isolated from patients with acute pyoinflammatory pleuropulmonary diseases, was studied. Antibiotic resistance dynamics of the infective agents under study to lincomycin, clindamycin, thienam, vancomycin was also detected. The inhibiting activity of oxytocin on the persistence properties of B. fragilis, P. melanogenica and P. anaerobius was noted. Under the influence of the preparations used changes in the sensitivity of the strains to a number of antibiotics of the lincosamide, carbapenem and glycopeptide groups were found to occur. The data thus obtained were indicative of the possible mechanisms of action of oxytocin in the treatment of acute pyoinflammatory pleuropulmonary diseases of anaerobic nonclostridial etiology.

Bacteroidaceae in Thromboembolic Disease: Effects of Cell Wall Components on Blood Coagulation In Vivo and In Vitro

PubMed Central

Bjornson, H. S.; Hill, E. O.

1973-01-01

The effects of Bacteroides sp., Fusobacterium mortiferum, Bacteroides fragilis, and Sphaerophorus necrophorus on various parameters of blood coagulation in vivo and in vitro were determined and compared to the coagulation effects of Escherichia coli and Salmonella minnesota, wild type and R595. Intravenous injection of washed cells, culture filtrate, lipopolysaccharide, or lipid A of the anaerobic gram-negative microorganisms into mice resulted in acceleration of coagulation. Lipopolysaccharide and lipid A of the anaerobic microorganisms had no apparent effect on circulating platelets in mice or rabbits and did not cause aggregation of human platelets in vitro. Washed cells, lipopolysaccharide, and lipid A of Bacteroides sp. and F. mortiferum also significantly accelerated the clotting time of recalcified platelet poor normal human plasma and C6-deficient rabbit plasma. Lipid A, but not lipopolysaccharide, of E. coli and washed cells of S. minnesota R595 accelerated coagulation by a similar mechanism. These results indicated that Bacteroides sp. and F. mortiferum can accelerate blood coagulation in vivo and in vitro by a mechanism which does not involve platelets or terminal components of complement. PMID:4594118

A Sense of Obligation: Cultural Differences in the Experience of Obligation.

PubMed

Buchtel, Emma E; Ng, Leo C Y; Norenzayan, Ara; Heine, Steven J; Biesanz, Jeremy C; Chen, Sylvia Xiaohua; Bond, Michael Harris; Peng, Qin; Su, Yanjie

2018-05-01

In this investigation of cultural differences in the experience of obligation, we distinguish between Confucian Role Ethics versus Relative Autonomy lay theories of motivation and illustrate them with data showing relevant cultural differences in both social judgments and intrapersonal experience. First, when judging others, Western European heritage culture (WEHC) participants (relative to Confucian heritage culture [CHC] participants) judged obligation-motivated actors more negatively than those motivated by agency (Study 1, N = 529). Second, in daily diary and situation sampling studies, CHC participants (relative to WEHC participants) perceived more congruency between their own agentic and obligated motivations, and more positive emotional associations with obligated motivations (Study 2, N = 200 and Study 3, N = 244). Agentic motivation, however, was universally associated with positive emotions. More research on a Role Ethics rather than Relative Autonomy conception of agency may improve our understanding of human motivation, especially across cultures.

Anaerobic

MedlinePlus

... oxygen." The term has many uses in medicine. Anaerobic bacteria are germs that can survive and grow where ... Infections like tetanus and gangrene are caused by anaerobic bacteria. Anaerobic infections typically cause abscesses (buildups of pus), ...

First National Survey of Antibiotic Susceptibility of the Bacteroides fragilis Group: Emerging Resistance to Carbapenems in Argentina

PubMed Central

Litterio, Mirta; Legaria, María C.; Castello, Liliana; Predari, Silvia C.; Di Martino, Ana; Rossetti, Adelaida; Rollet, Raquel; Carloni, Graciela; Bianchini, Hebe; Cejas, Daniela; Radice, Marcela; Gutkind, Gabriel

2012-01-01

The antibiotic susceptibility rates of 363 clinical Bacteroides fragilis group isolates collected from 17 centers in Argentina during the period from 2006 to 2009 were as follows: piperacillin-tazobactam, 99%; ampicillin-sulbactam, 92%; cefoxitin, 72%; tigecycline, 100%; moxifloxacin, 91%; and clindamycin, 52%. No metronidazole resistance was detected in these isolates during this time period. Resistance to imipenem, doripenem, and ertapenem was observed in 1.1%, 1.6%, and 2.3% of B. fragilis group strains, respectively. B. fragilis species showed a resistance profile of 1.5% to imipenem, 1.9% to doripenem, and 2.4% to ertapenem. This is the first report of carbapenem resistance in Argentina. The cfiA gene was present in 8 out of 23 isolates, all of them belonging to the B. fragilis species and displaying reduced susceptibility or resistance to carbapenems (MICs ≥ 4 μg/ml). Three out of eight cfiA-positive isolates were fully resistant to carbapenems, while 5 out of 8 isolates showed low-level resistance (MICs, 4 to 8 μg/ml). The inhibition by EDTA was a good predictor of the presence of metallo-β-lactamases in the fully resistant B. fragilis strains, but discrepant results were observed for low-level resistant isolates. B. fragilis was more susceptible to antimicrobial agents than other Bacteroides species. Bacteroides vulgatus species was the most resistant to ampicillin-sulbactam and piperacillin-tazobactam, and B. thetaiotaomicron/ovatus strains showed the highest level of resistance to carbapenems, with an unknown resistance mechanism. B. vulgatus and the uncommon non-Bacteroides fragilis species were the most resistant to moxifloxacin, showing an overall resistance rate of 15.1%. PMID:22232282

[Identification of anaerobic gram-negative bacilli isolated from various clinical specimens and determination of antibiotic resistance profiles with E-test methods].

PubMed

Demir, Cengiz; Keşli, Recep

2018-01-01

The aim of this study was to identify gram-negative anaerobic bacilli isolated from various clinical specimens that were obtained from patients with suspected anaerobic infections and to determine the antibiotic resistance profiles by using the antibiotic concentration gradient method. The study was performed in Afyon Kocatepe University Ahmet Necdet Sezer Research and Practice Hospital, Medical Microbiology Laboratory between 1 November 2014 and 30 October 2015. Two hundred and seventyeight clinical specimens accepted for anaerobic culture were enrolled in the study. All the samples were cultivated anaerobically by using Schaedler agar with 5% defibrinated sheep blood and Schaedler broth. The isolated anaerobic gram-negative bacilli were identified by using both the conventional methods and automated identification system (VITEK 2, bioMerieux, France). Antibiotic susceptibility tests were performed with antibiotic concentration gradient method (E-test, bioMerieux, France); against penicillin G, clindamycin, cefoxitin, metronidazole, moxifloxacin, imipenem, meropenem, ertapenem and doripenem for each isolate. Of the 28 isolated anaerobic gram-negative bacilli; 14 were identified as Bacteroides fragilis group, 9 were Prevotella spp., and 5 were Fusobacterium spp. The highest resistance rate was found against penicillin (78.5%) and resistance rates against clindamycin and cefoxitin were found as 17.8% and 21.4%, respectively. No resistance was found against metronidazole, moxifloxacin, imipenem, meropenem, ertapenem and doripenem. As a result, isolation and identification of anaerobic bacteria are difficult, time-consuming and more expensive when compared with the cost of aerobic culture. The rate of anaerobic bacteria isolation may be increased by obtaining the appropriate clinical specimen and appropriate transportation of these specimens. We believe that the data obtained from the study in our center may offer benefits for the follow up and treatment of infections

"Obligated aliens": recognizing sperm donors' ethical obligation to disclose genetic information.

PubMed

Tamir, Sivan

2013-03-01

Sperm donors' obligations are typically constrained to the immediate circumstances surrounding the donation and to its time frame. This paper makes the case for recognizing an ongoing ethical obligation that binds sperm donors to disclose, in a timely manner, meaningful genetic information to recipients and donor-conceived children. The paper delineates and conceptualizes the suggested (potentially reciprocal) duty and argues that it is not the genetic link between the donor and the donor-conceived child that binds donors by said duty, but rather social responsibility. Accordingly, an original perception of the donor as an obligated alien is suggested and developed. The main thesis of the paper is supported inter alia by a comparison between transmitting infectious diseases and passing faulty genes on to donor-conceived children. The paper also provides an in-depth analysis of the conflicting interests of the parties generated by such an obligation and proposes a model for embedding this ethical duty in a (legal) contractual framework.

Studies on the pathogenicity of anaerobes, especially Prevotella bivia, in a rat pyometra model.

PubMed Central

Mikamo, H; Kawazoe, K; Izumi, K; Watanabe, K; Ueno, K; Tamaya, T

1998-01-01

OBJECTIVE: Prevotella bivia is one of the anaerobic bacteria that resides in the flora of the female genital tract. We studied the pathogenicity of P. bivia in a rat pyometra model. METHODS: The experimental animal (rat) model of pyometra was developed to investigate the pathogenicity of P. bivia in a rat pyometra model. RESULTS: In the groups inoculated with aerobes alone, the infection rate was 10% (1/10) in the Staphylococcus aureus- or Staphylococcus agalactiae-inoculated group and 20% (2/10) in the Escherichia coli-inoculated group. Infection was not established in the groups inoculated with anaerobes alone. High infection rates were observed in all the mixed-infection groups. In the S. agalactiae- and Bacteroides fragilis-, S. agalactiae- and P. bivia-, F. coli- and B. fragilis-, and E. coli- and P. bivia-inoculated groups, an infection rate of 100% (10/10) was demonstrated. The efficacy of antibiotics such as flomoxef (FMOX) could be determined using a rat pyometra model. In relation to the alteration of vaginal microbial flora during the menstrual cycle, estrogen increased the growth of P. bivia. CONCLUSION: Mixture of aerobic bacteria and P. bivia increased the pathogenicity of P. bivia. Estrogen would be useful for raising up the inflammatory change of the uterus in experimental models of genital tract infection due to P. bivia. PMID:9702587

Activity of Telithromycin (HMR 3647) against Anaerobic Bacteria Compared to Those of Eight Other Agents by Time-Kill Methodology†

PubMed Central

Credito, Kim L.; Ednie, Lois M.; Jacobs, Michael R.; Appelbaum, Peter C.

1999-01-01

Time-kill studies examined the activities of telithromycin (HMR 3647), erythromycin A, azithromycin, clarithromycin, roxithromycin, clindamycin, pristinamycin, amoxicillin-clavulanate, and metronidazole against 11 gram-positive and gram-negative anaerobic bacteria. Time-kill studies were carried out with the addition of Oxyrase in order to prevent the introduction of CO2. Macrolide-azalide-ketolide MICs were 0.004 to 32.0 μg/ml. Of the latter group, telithromycin had the lowest MICs, especially against non-Bacteroides fragilis group strains, followed by azithromycin, clarithromycin, erythromycin A, and roxithromycin. Clindamycin was active (MIC ≤ 2.0 μg/ml) against all anaerobes except Peptostreptococcus magnus and Bacteroides thetaiotaomicron, while pristinamycin MICs were 0.06 to 4.0 μg/ml. Amoxicillin-clavulanate had MICs of ≤1.0 μg/ml, while metronidazole was active (MICs, 0.03 to 2.0 μg/ml) against all except Propionibacterium acnes. After 48 h at twice the MIC, telithromycin was bactericidal (≥99.9% killing) against 6 strains, with 99% killing of 9 strains and 90% killing of 10 strains. After 24 h at twice the MIC, 90, 99, and 99.9% killing of nine, six, and three strains, respectively, occurred. Lower rates of killing were seen at earlier times. Similar kill kinetics relative to the MIC were seen with other macrolides. After 48 h at the MIC, clindamycin was bactericidal against 8 strains, with 99 and 90% killing of 9 and 10 strains, respectively. After 24 h, 90% killing of 10 strains occurred at the MIC. The kinetics of clindamycin were similar to those of pristinamycin. After 48 h at the MIC, amoxicillin-clavulanate showed 99.9% killing of seven strains, with 99% killing of eight strains and 90% killing of nine strains. At four times the MIC, metronidazole was bactericidal against 8 of 10 strains tested after 48 h and against all 10 strains after 24 h; after 12 h, 99% killing of all 10 strains occurred. PMID:10428930

Activity of telithromycin (HMR 3647) against anaerobic bacteria compared to those of eight other agents by time-kill methodology.

PubMed

Credito, K L; Ednie, L M; Jacobs, M R; Appelbaum, P C

1999-08-01

Time-kill studies examined the activities of telithromycin (HMR 3647), erythromycin A, azithromycin, clarithromycin, roxithromycin, clindamycin, pristinamycin, amoxicillin-clavulanate, and metronidazole against 11 gram-positive and gram-negative anaerobic bacteria. Time-kill studies were carried out with the addition of Oxyrase in order to prevent the introduction of CO(2). Macrolide-azalide-ketolide MICs were 0.004 to 32.0 microg/ml. Of the latter group, telithromycin had the lowest MICs, especially against non-Bacteroides fragilis group strains, followed by azithromycin, clarithromycin, erythromycin A, and roxithromycin. Clindamycin was active (MIC anaerobes except Peptostreptococcus magnus and Bacteroides thetaiotaomicron, while pristinamycin MICs were 0.06 to 4.0 microg/ml. Amoxicillin-clavulanate had MICs of /=99.9% killing) against 6 strains, with 99% killing of 9 strains and 90% killing of 10 strains. After 24 h at twice the MIC, 90, 99, and 99.9% killing of nine, six, and three strains, respectively, occurred. Lower rates of killing were seen at earlier times. Similar kill kinetics relative to the MIC were seen with other macrolides. After 48 h at the MIC, clindamycin was bactericidal against 8 strains, with 99 and 90% killing of 9 and 10 strains, respectively. After 24 h, 90% killing of 10 strains occurred at the MIC. The kinetics of clindamycin were similar to those of pristinamycin. After 48 h at the MIC, amoxicillin-clavulanate showed 99.9% killing of seven strains, with 99% killing of eight strains and 90% killing of nine strains. At four times the MIC, metronidazole was bactericidal against 8 of 10 strains tested after 48 h and against all 10 strains after 24 h; after 12 h, 99% killing of all 10 strains occurred.

Novel [NiFe]- and [FeFe]-Hydrogenase Gene Transcripts Indicative of Active Facultative Aerobes and Obligate Anaerobes in Earthworm Gut Contents▿†

PubMed Central

Schmidt, Oliver; Wüst, Pia K.; Hellmuth, Susanne; Borst, Katharina; Horn, Marcus A.; Drake, Harold L.

2011-01-01

The concomitant occurrence of molecular hydrogen (H2) and organic acids along the alimentary canal of the earthworm is indicative of ongoing fermentation during gut passage. Fermentative H2 production is catalyzed by [FeFe]-hydrogenases and group 4 [NiFe]-hydrogenases in obligate anaerobes (e.g., Clostridiales) and facultative aerobes (e.g., Enterobacteriaceae), respectively, functional groups that might respond differently to contrasting redox conditions. Thus, the objectives of this study were to assess the redox potentials of the alimentary canal of Lumbricus terrestris and analyze the hydrogenase transcript diversities of H2 producers in glucose-supplemented gut content microcosms. Although redox potentials in the core of the alimentary canal were variable on an individual worm basis, average redox potentials were similar. The lowest redox potentials occurred in the foregut and midgut regions, averaging 40 and 110 mV, respectively. Correlation plots between hydrogenase amino acid sequences and 16S rRNA gene sequences indicated that closely related hydrogenases belonged to closely related taxa, whereas distantly related hydrogenases did not necessarily belong to distantly related taxa. Of 178 [FeFe]-hydrogenase gene transcripts, 177 clustered in 12 Clostridiales-affiliated operational taxonomic units, the majority of which were indicative of heretofore unknown hydrogenases. Of 86 group 4 [NiFe]-hydrogenase gene transcripts, 79% and 21% were affiliated with organisms in the Enterobacteriaceae and Aeromonadaceae, respectively. The collective results (i) suggest that fermenters must cope with variable and moderately oxidative redox conditions along the alimentary canal, (ii) demonstrate that heretofore undetected hydrogenases are present in the earthworm gut, and (iii) corroborate previous findings implicating Clostridiaceae and Enterobacteriaceae as active fermentative taxa in earthworm gut content. PMID:21784904

New insights into the role of phosphate-free lipids in anaerobic environments

NASA Astrophysics Data System (ADS)

Schubotz, F.; De Santiago Torio, A.; Kuehl, J.; Grant, C.; Rahn-Lee, L.; Arkin, A. P.; Deutschbauer, A. M.; Summons, R. E.; Bosak, T.

2016-02-01

Recent investigations have revealed an abundance of phosphate-free glycolipids and aminolipids, classically assigned to oxygenic phototrophs, in anoxic environments where anaerobic microorganisms prevail. Phosphorus-free lipids in oxic environments are thought to indicate an adaptation to phosphorus limitation, but their significance in anoxic environments is unclear, because these environments are not typically thought of as phosphorus-limited. We hypothesize that glycolipids and aminolipids play an overlooked and potentially integral role in anaerobic bacteria from marine and terrestrial environments and test this hypothesis in environmentally relevant model anaerobic deltaproteobacteria. None of the investigated strains of the sulfate-reducing genus Desulfovibrio synthesize glycolipids under normal growth conditions or during nitrogen limitation. However, when growing in phosphate-limited conditions, all investigated organisms undergo a nearly complete replacement of phospholipids by glycolipids. Some phosphate-starved organisms, such as D. fructosivorans, are also able to synthesize betaine lipids. Analyses of mutants of Desulfovibrio alaskensis G20 identify genes responsible for the biosynthesis of aminolipids (Dde_3661) and glycolipids (Dde_3613). Fitness experiments using tagged transposon mutant libraries of G20 identify these two genes and 90 other genes important for fitness of this organism during phosphate limitation. These experiments identify for the first time betaine lipids and glycolipids in sulfate-reducing bacteria and demonstrate the importance of these non-phosphorus lipids as substitute lipids in obligate anaerobes. These findings suggest that phosphorus availability limits microbial growth and activity in a more widespread range of environments than previously thought.

Persistence of Bacteroides ovatus under simulated sunlight irradiation

PubMed Central

2014-01-01

Background Bacteroides ovatus, a member of the genus Bacteroides, is considered for use in molecular-based methods as a general fecal indicator. However, knowledge on its fate and persistence after a fecal contamination event remains limited. In this study, the persistence of B. ovatus was evaluated under simulated sunlight exposure and in conditions similar to freshwater and seawater. By combining propidium monoazide (PMA) treatment and quantitative polymerase chain reaction (qPCR) detection, the decay rates of B. ovatus were determined in the presence and absence of exogenous photosensitizers and in salinity up to 39.5 parts per thousand at 27°C. Results UVB was found to be important for B. ovatus decay, averaging a 4 log10 of decay over 6 h of exposure without the presence of extracellular photosensitizers. The addition of NaNO2, an exogenous sensitizer producing hydroxyl radicals, did not significantly change the decay rate of B. ovatus in both low and high salinity water, while the exogenous sensitizer algae organic matter (AOM) slowed down the decay of B. ovatus in low salinity water. At seawater salinity, the decay rate of B. ovatus was slower than that in low salinity water, except when both NaNO2 and AOM were present. Conclusion The results of laboratory experiments suggest that if B. ovatus is released into either freshwater or seawater environment in the evening, 50% of it may be intact by the next morning; if it is released at noon, only 50% may be intact after a mere 5 min of full spectrum irradiation on a clear day. This study provides a mechanistic understanding to some of the important environmental relevant factors that influenced the inactivation kinetics of B. ovatus in the presence of sunlight irradiation, and would facilitate the use of B. ovatus to indicate the occurrence of fecal contamination. PMID:24993443

Anaerobic Microbial Degradation of Hydrocarbons: From Enzymatic Reactions to the Environment.

PubMed

Rabus, Ralf; Boll, Matthias; Heider, Johann; Meckenstock, Rainer U; Buckel, Wolfgang; Einsle, Oliver; Ermler, Ulrich; Golding, Bernard T; Gunsalus, Robert P; Kroneck, Peter M H; Krüger, Martin; Lueders, Tillmann; Martins, Berta M; Musat, Florin; Richnow, Hans H; Schink, Bernhard; Seifert, Jana; Szaleniec, Maciej; Treude, Tina; Ullmann, G Matthias; Vogt, Carsten; von Bergen, Martin; Wilkes, Heinz

2016-01-01

naphthalene), W-cofactor-containing enzymes for reductive dearomatization of benzoyl-CoA (class II benzoyl-CoA reductase) in obligate anaerobes and addition of water to acetylene, fermentative formation of cyclohexanecarboxylate from benzoate, and methanogenic degradation of hydrocarbons. © 2016 S. Karger AG, Basel.

Culturable prokaryotic diversity of deep, gas hydrate sediments: first use of a continuous high-pressure, anaerobic, enrichment and isolation system for subseafloor sediments (DeepIsoBUG)

PubMed Central

Parkes, R John; Sellek, Gerard; Webster, Gordon; Martin, Derek; Anders, Erik; Weightman, Andrew J; Sass, Henrik

2009-01-01

Deep subseafloor sediments may contain depressurization-sensitive, anaerobic, piezophilic prokaryotes. To test this we developed the DeepIsoBUG system, which when coupled with the HYACINTH pressure-retaining drilling and core storage system and the PRESS core cutting and processing system, enables deep sediments to be handled without depressurization (up to 25 MPa) and anaerobic prokaryotic enrichments and isolation to be conducted up to 100 MPa. Here, we describe the system and its first use with subsurface gas hydrate sediments from the Indian Continental Shelf, Cascadia Margin and Gulf of Mexico. Generally, highest cell concentrations in enrichments occurred close to in situ pressures (14 MPa) in a variety of media, although growth continued up to at least 80 MPa. Predominant sequences in enrichments were Carnobacterium, Clostridium, Marinilactibacillus and Pseudomonas, plus Acetobacterium and Bacteroidetes in Indian samples, largely independent of media and pressures. Related 16S rRNA gene sequences for all of these Bacteria have been detected in deep, subsurface environments, although isolated strains were piezotolerant, being able to grow at atmospheric pressure. Only the Clostridium and Acetobacterium were obligate anaerobes. No Archaea were enriched. It may be that these sediment samples were not deep enough (total depth 1126–1527 m) to obtain obligate piezophiles. PMID:19694787

In Vitro Activities of Ramoplanin, Teicoplanin, Vancomycin, Linezolid, Bacitracin, and Four Other Antimicrobials against Intestinal Anaerobic Bacteria

PubMed Central

Citron, D. M.; Merriam, C. V.; Tyrrell, K. L.; Warren, Y. A.; Fernandez, H.; Goldstein, E. J. C.

2003-01-01

By using an agar dilution method, the in vitro activities of ramoplanin, teicoplanin, vancomycin, linezolid, and five other agents were determined against 300 gram-positive and 54 gram-negative strains of intestinal anaerobes. Ramoplanin was active at ≤2 μg/ml against 287 of 300 (95.7%) gram-positive organisms, including 18 strains of Clostridium difficile for which MICs of ramoplanin were 0.25 to 0.5 μg/ml; for 3 of these, linezolid MICs were 8 to 16 μg/ml. Nineteen Clostridium innocuum strains for which the vancomycin MIC at which 90% of strains were inhibited was 16 μg/ml were susceptible to ramoplanin at 0.06 to 0.25 μg/ml and to teicoplanin at 0.125 to 1.0 μg/ml. All strains of Eubacterium, Actinomyces, Propionibacterium, and Peptostreptococcus spp. were inhibited by ≤0.25 μg of ramoplanin per ml and ≤1 μg of vancomycin per ml. Ramoplanin was also active at ≤4 μg/ml against 15 of 22 of the Prevotella and Porphyromonas strains tested, but ramoplanin MICs for all 31 strains of the Bacteroides fragilis group, the Fusobacterium mortiferum-Fusobacterium varium group, and Veillonella spp. were ≥256 μg/ml. Ramoplanin displays excellent activity against C. difficile and other gram-positive enteric anaerobes, including vancomycin-resistant strains; however, it has poor activity against most gram-negative anaerobes and thus potentially has a lesser effect on the ecological balance of normal fecal flora. PMID:12821492

Effect of cryopreservation and lyophilization on viability and growth of strict anaerobic human gut microbes.

PubMed

Bircher, Lea; Geirnaert, Annelies; Hammes, Frederik; Lacroix, Christophe; Schwab, Clarissa

2018-04-17

Strict anaerobic gut microbes have been suggested as 'next-generation probiotics' for treating several intestinal disorders. The development of preservation techniques is of major importance for therapeutic application. This study investigated cryopreservation (-80°C) and lyophilization survival and storage stability (4°C for 3 months) of the strict anaerobic gut microbes Bacteroides thetaiotaomicron, Faecalibacterium prausnitzii, Roseburia intestinalis, Anaerostipes caccae, Eubacterium hallii and Blautia obeum. To improve preservation survival, protectants sucrose and inulin (both 5% w/v) were added for lyophilization and were also combined with glycerol (15% v/v) for cryopreservation. Bacterial fitness, evaluated by maximum growth rate and lag phase, viability and membrane integrity were determined using a standardized growth assay and by flow cytometry as markers for preservation resistance. Lyophilization was more detrimental to viability and fitness than cryopreservation, but led to better storage stability. Adding sucrose and inulin enhanced viability and the proportion of intact cells during lyophilization of all strains. Viability of protectant-free B. thetaiotaomicron, A. caccae and F. prausnitzii was above 50% after cryopreservation and storage and increased to above 80% if protectants were present. The addition of glycerol, sucrose and inulin strongly enhanced the viability of B. obeum, E. hallii and R. intestinalis from 0.03-2% in protectant-free cultures to 11-37%. This is the first study that quantitatively compared the effect of cryopreservation and lyophilization and the addition of selected protectants on viability and fitness of six strict anaerobic gut microbes. Our results suggest that efficiency of protectants is process- and species-specific. © 2018 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Morphology, antigenicity, and nucleic acid content of the Bacteroides sp. used in the culture of Entamoeba histolytica.

PubMed

Albach, R A; Shaffer, J G; Watson, R H

1965-10-01

Albach, Richard A. (Lutheran General Hospital, Park Ridge, Ill.), James G. Shaffer, and Robert H. Watson. Morphology, antigenicity, and nucleic acid content of the Bacteroides sp. used in the culture of Entamoeba histolytica. J. Bacteriol. 90:1045-1053. 1965.-Certain changes in morphology, antigenicity, and nucleic acid content that occur in a culture of Bacteroides sp. in the presence of penicillin G in CLG medium are described. This "variant" is one of seven recovered in several laboratories, all of which are descendants of the original Bacteroides isolated by Shaffer and Frye. Penicillin-inhibited cells of this culture are currently being used in the routine propagation of Entamoeba histolytica in CLG medium. Evidence is presented for the loss of ability to react with antibody in these penicillin-inhibited bacteria in CLG medium, when studied by fluorescent-antibody techniques. The implications of the antigenic changes observed as they pertain to similar antigenic studies of the amoebas are discussed. A pronounced reduction in the ribonucleic acid (RNA) content of such penicillin-inhibited cells was also observed. The potential importance of the changes that occur in the RNA of these cells with respect to considerations of the growth requirements of the amoebas is also discussed.

Microbial Populations Associated with Treatment of an Industrial Dye Effluent in an Anaerobic Baffled Reactor

PubMed Central

Plumb, Jason J.; Bell, Joanne; Stuckey, David C.

2001-01-01

Fluorescent in situ hybridization (FISH) using 16S and 23S rRNA-targeted probes together with construction of an archaeal 16S ribosomal DNA (rDNA) clone library was used to characterize the microbial populations of an anaerobic baffled reactor successfully treating industrial dye waste. Wastewater produced during the manufacture of food dyes containing several different azo and other dye compounds was decolorized and degraded under sulfidogenic and methanogenic conditions. Use of molecular methods to describe microbial populations showed that a diverse group of Bacteria and Archaea was involved in this treatment process. FISH enumeration showed that members of the gamma subclass of the class Proteobacteria and bacteria in the Cytophaga-Flexibacter-Bacteroides phylum, together with sulfate-reducing bacteria, were prominent members of a mixed bacterial population. A combination of FISH probing and analysis of 98 archaeal 16S rDNA clone inserts revealed that together with the bacterial population, a methanogenic population dominated by Methanosaeta species and containing species of Methanobacterium and Methanospirillum and a relatively unstudied methanogen, Methanomethylovorans hollandica, contributed to successful anaerobic treatment of the industrial waste. We suggest that sulfate reducers, or more accurately sulfidogenic bacteria, together with M. hollandica contribute considerably to the treatment process through metabolism of dye-associated sulfonate groups and subsequent conversion of sulfur compounds to carbon dioxide and methane. PMID:11425746

Caldanaerobacter uzonensis sp. nov., an anaerobic, thermophilic, heterotrophic bacterium isolated from a hot spring.

PubMed

Kozina, Irina V; Kublanov, Ilya V; Kolganova, Tatyana V; Chernyh, Nikolai A; Bonch-Osmolovskaya, Elizaveta A

2010-06-01

An anaerobic thermophilic bacterium, strain K67(T), was isolated from a terrestrial hot spring of Uzon Caldera, Kamchatka Peninsula. Analysis of the 16S rRNA gene sequence revealed that the novel isolate belongs to the genus Caldanaerobacter, with 95 % 16S rRNA gene sequence similarity to Caldanaerobacter subterraneus subsp. subterraneus SEBR 7858(T), suggesting that it represents a novel species of the genus Caldanaerobacter. Strain K67(T) was characterized as an obligate anaerobe, a thermophile (growth at 50-75 degrees capital ES, Cyrillic; optimum 68-70 degrees C), a neutrophile (growth at pH(25 degrees C) 4.8-8.0; optimum pH(25 degrees C) 6.8) and an obligate organotroph (growth by fermentation of various sugars, peptides and polysaccharides). Major fermentation products were acetate, H2 and CO2; ethanol, lactate and l-alanine were formed in smaller amounts. Thiosulfate stimulated growth and was reduced to hydrogen sulfide. Nitrate, sulfate, sulfite and elemental sulfur were not reduced and did not stimulate growth. Thus, according to the strain's phylogenetic position and phenotypic novelties (lower upper limit of temperature range for growth, the ability to grow on arabinose, the inability to reduce elemental sulfur and the formation of alanine as a minor fermentation product), the novel species Caldanaerobacter uzonensis sp. nov. is proposed, with the type strain K67(T) (=DSM 18923(T) =VKM capital VE, Cyrillic-2408(T)).

Microbes vs. chemistry in the origin of the anaerobic gut lumen.

PubMed

Friedman, Elliot S; Bittinger, Kyle; Esipova, Tatiana V; Hou, Likai; Chau, Lillian; Jiang, Jack; Mesaros, Clementina; Lund, Peder J; Liang, Xue; FitzGerald, Garret A; Goulian, Mark; Lee, Daeyeon; Garcia, Benjamin A; Blair, Ian A; Vinogradov, Sergei A; Wu, Gary D

2018-04-17

The succession from aerobic and facultative anaerobic bacteria to obligate anaerobes in the infant gut along with the differences between the compositions of the mucosally adherent vs. luminal microbiota suggests that the gut microbes consume oxygen, which diffuses into the lumen from the intestinal tissue, maintaining the lumen in a deeply anaerobic state. Remarkably, measurements of luminal oxygen levels show nearly identical pO 2 (partial pressure of oxygen) profiles in conventional and germ-free mice, pointing to the existence of oxygen consumption mechanisms other than microbial respiration. In vitro experiments confirmed that the luminal contents of germ-free mice are able to chemically consume oxygen (e.g., via lipid oxidation reactions), although at rates significantly lower than those observed in the case of conventionally housed mice. For conventional mice, we also show that the taxonomic composition of the gut microbiota adherent to the gut mucosa and in the lumen throughout the length of the gut correlates with oxygen levels. At the same time, an increase in the biomass of the gut microbiota provides an explanation for the reduction of luminal oxygen in the distal vs. proximal gut. These results demonstrate how oxygen from the mammalian host is used by the gut microbiota, while both the microbes and the oxidative chemical reactions regulate luminal oxygen levels, shaping the composition of the microbial community throughout different regions of the gut.

Vaginal lactobacilli inhibiting growth of Gardnerella vaginalis, Mobiluncus and other bacterial species cultured from vaginal content of women with bacterial vaginosis.

PubMed

Skarin, A; Sylwan, J

1986-12-01

On a solid agar medium the growth-inhibitory effect of 9 Lactobacillus strains cultured from vaginal content was tested on bacteria cultured from vaginal content of women with bacterial vaginosis: Mobiluncus, Gardnerella vaginalis, Bacteroides and anaerobic cocci. Inhibition zones were observed in the growth of all of the strains isolated from women with bacterial vaginosis around all lactobacilli. The inhibitory effect of the lactobacilli was further tested on various anaerobic and facultatively anaerobic species, both type strains and fresh extragenitally cultured strains. Four Bacteroides fragilis strains as well as 2 out of 4 Staphylococcus aureus strains were clearly inhibited by the lactobacilli. The inhibition zones were generally wider at pH 5.5 than at 6.0. For all inhibited strains, (the S. aureus excepted) a low pH on the agar around the lactobacilli correlated to wider growth-inhibition zones.

Influence of Environmental and Genetic Factors Linked to Celiac Disease Risk on Infant Gut Colonization by Bacteroides Species▿

PubMed Central

Sánchez, Ester; De Palma, Giada; Capilla, Amalia; Nova, Esther; Pozo, Tamara; Castillejo, Gemma; Varea, Vicente; Marcos, Ascensión; Garrote, José Antonio; Polanco, Isabel; López, Ana; Ribes-Koninckx, Carmen; García-Novo, Maria Dolores; Calvo, Carmen; Ortigosa, Luis; Palau, Francesc; Sanz, Yolanda

2011-01-01

Celiac disease (CD) is an immune-mediated enteropathy involving genetic and environmental factors whose interaction might influence disease risk. The aim of this study was to determine the effects of milk-feeding practices and the HLA-DQ genotype on intestinal colonization of Bacteroides species in infants at risk of CD development. This study included 75 full-term newborns with at least one first-degree relative suffering from CD. Infants were classified according to milk-feeding practice (breast-feeding or formula feeding) and HLA-DQ genotype (high or low genetic risk). Stools were analyzed at 7 days, 1 month, and 4 months by PCR and denaturing gradient gel electrophoresis (DGGE). The Bacteroides species diversity index was higher in formula-fed infants than in breast-fed infants. Breast-fed infants showed a higher prevalence of Bacteroides uniformis at 1 and 4 months of age, while formula-fed infants had a higher prevalence of B. intestinalis at all sampling times, of B. caccae at 7 days and 4 months, and of B. plebeius at 4 months. Infants with high genetic risk showed a higher prevalence of B. vulgatus, while those with low genetic risk showed a higher prevalence of B. ovatus, B. plebeius, and B. uniformis. Among breast-fed infants, the prevalence of B. uniformis was higher in those with low genetic risk than in those with high genetic risk. Among formula-fed infants, the prevalence of B. ovatus and B. plebeius was increased in those with low genetic risk, while the prevalence of B. vulgatus was higher in those with high genetic risk. The results indicate that both the type of milk feeding and the HLA-DQ genotype influence the colonization process of Bacteroides species, and possibly the disease risk. PMID:21642397

Lay obligations in professional relations.

PubMed

Benjamin, M

1985-02-01

Little has been written recently about the obligations of lay people in professional relationships. Yet the Code of Medical Ethics adopted by the American Medical Association in 1847 included an extensive statement on "Obligations of patients to their physicians'. After critically examining the philosophical foundations of this statement, I provide an alternative account of lay obligations in professional relationships. Based on a hypothetical social contract and included in a full specification of professional as well as lay obligations, this account requires lay people to honor commitments and disclose relevant information. Ethically, the account assumes that all parties in lay-professional relationships should be given equal consideration and respect in determining rights and obligations. Factually, it assumes that the treatment of many illnesses and injuries required collaboration and cooperation among lay persons and health professionals, that medical resources and personnel are limited, and that medicine, nursing, and related health professions, are, in MacIntyre's sense, practices.

USE OF BACTEROIDES PCR-BASED METHODS TO EXAMINE FECAL CONTAMINATION SOURCES IN TROPICAL COASTAL WATERS

EPA Science Inventory

Several library independent Microbial Source Tracking methods have been developed to rapidly determine the source of fecal contamination. Thus far, none of these methods have been tested in tropical marine waters. In this study, we used a Bacteroides 16S rDNA PCR-based...

47 CFR 7.5 - General Obligations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false General Obligations. 7.5 Section 7.5 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL ACCESS TO VOICEMAIL AND INTERACTIVE MENU SERVICES AND EQUIPMENT BY PEOPLE WITH DISABILITIES Obligations-What Must Covered Entities Do? § 7.5 General Obligations...

47 CFR 7.5 - General Obligations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 1 2014-10-01 2014-10-01 false General Obligations. 7.5 Section 7.5 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL ACCESS TO VOICEMAIL AND INTERACTIVE MENU SERVICES AND EQUIPMENT BY PEOPLE WITH DISABILITIES Obligations-What Must Covered Entities Do? § 7.5 General Obligations...

47 CFR 7.5 - General Obligations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 1 2013-10-01 2013-10-01 false General Obligations. 7.5 Section 7.5 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL ACCESS TO VOICEMAIL AND INTERACTIVE MENU SERVICES AND EQUIPMENT BY PEOPLE WITH DISABILITIES Obligations-What Must Covered Entities Do? § 7.5 General Obligations...

47 CFR 7.5 - General Obligations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 1 2011-10-01 2011-10-01 false General Obligations. 7.5 Section 7.5 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL ACCESS TO VOICEMAIL AND INTERACTIVE MENU SERVICES AND EQUIPMENT BY PEOPLE WITH DISABILITIES Obligations-What Must Covered Entities Do? § 7.5 General Obligations...

47 CFR 7.5 - General Obligations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 1 2012-10-01 2012-10-01 false General Obligations. 7.5 Section 7.5 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL ACCESS TO VOICEMAIL AND INTERACTIVE MENU SERVICES AND EQUIPMENT BY PEOPLE WITH DISABILITIES Obligations-What Must Covered Entities Do? § 7.5 General Obligations...

Biological conversion of biogas to methanol using methanotrophs isolated from solid-state anaerobic digestate.

PubMed

Sheets, Johnathon P; Ge, Xumeng; Li, Yueh-Fen; Yu, Zhongtang; Li, Yebo

2016-02-01

The aim of this work was to isolate methanotrophs (methane oxidizing bacteria) that can directly convert biogas produced at a commercial anaerobic digestion (AD) facility to methanol. A methanotrophic bacterium was isolated from solid-state anaerobic digestate. The isolate had characteristics comparable to obligate methanotrophs from the genus Methylocaldum. This newly isolated methanotroph grew on biogas or purified CH4 and successfully converted biogas from AD to methanol. Methanol production was achieved using several methanol dehydrogenase (MDH) inhibitors and formate as an electron donor. The isolate also produced methanol using phosphate with no electron donor or using formate with no MDH inhibitor. The maximum methanol concentration (0.43±0.00gL(-1)) and 48-h CH4 to methanol conversion (25.5±1.1%) were achieved using biogas as substrate and a growth medium containing 50mM phosphate and 80mM formate. Copyright © 2015 Elsevier Ltd. All rights reserved.

Oral and dental infections with anaerobic bacteria: clinical features, predominant pathogens, and treatment.

PubMed

Tanner, A; Stillman, N

1993-06-01

Microbial populations colonizing the teeth are a major source of pathogens responsible for oral and dental infections, including periodontal diseases, gingivitis, pericoronitis, endodontitis, peri-implantitis, and postextraction infections. Each entity has distinct clinical and microbial features. Bacterial species associated with oral infections include Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus, Campylobacter rectus, Eubacterium species, Fusobacterium nucleatum, Eikenella corrodens, and Peptostreptococcus micros. Treponema pallidum-related spirochetes have been associated with acute necrotizing ulcerative gingivitis. Porphyromonas endodontalis appears to be specifically related to endodontic infections. Oral infections in medically compromised patients, including those with AIDS, are associated with similar species and are usually complicated by superinfection with enteric and Candida species. Isolation of species causing oral infections requires the collection of appropriate samples and the use of strictly anaerobic techniques. Rapid selective culture, immunofluorescence, and DNA probe methods have been developed for the identification of these oral species. The varied measures required in the management of oral and dental infections may include antimicrobial therapy. Accurate microbiological diagnosis, including antibiotic susceptibility testing, is indicated for cases that do not respond to therapy.

10 CFR 600.20 - Maximum DOE obligation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... DOE obligation. (a) The maximum DOE obligation to the recipient is— (1) For monetary awards, the amount shown in the award as the amount of DOE funds obligated, and (2) Any designated property. (b) DOE... 10 Energy 4 2011-01-01 2011-01-01 false Maximum DOE obligation. 600.20 Section 600.20 Energy...

10 CFR 600.20 - Maximum DOE obligation.

Code of Federal Regulations, 2013 CFR

2013-01-01

... DOE obligation. (a) The maximum DOE obligation to the recipient is— (1) For monetary awards, the amount shown in the award as the amount of DOE funds obligated, and (2) Any designated property. (b) DOE... 10 Energy 4 2013-01-01 2013-01-01 false Maximum DOE obligation. 600.20 Section 600.20 Energy...

10 CFR 600.20 - Maximum DOE obligation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... DOE obligation. (a) The maximum DOE obligation to the recipient is— (1) For monetary awards, the amount shown in the award as the amount of DOE funds obligated, and (2) Any designated property. (b) DOE... 10 Energy 4 2012-01-01 2012-01-01 false Maximum DOE obligation. 600.20 Section 600.20 Energy...

10 CFR 600.20 - Maximum DOE obligation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... DOE obligation. (a) The maximum DOE obligation to the recipient is— (1) For monetary awards, the amount shown in the award as the amount of DOE funds obligated, and (2) Any designated property. (b) DOE... 10 Energy 4 2014-01-01 2014-01-01 false Maximum DOE obligation. 600.20 Section 600.20 Energy...

Multiple Signals Govern Utilization of a Polysaccharide in the Gut Bacterium Bacteroides thetaiotaomicron.

PubMed

Schwalm, Nathan D; Townsend, Guy E; Groisman, Eduardo A

2016-10-11

The utilization of simple sugars is widespread across all domains of life. In contrast, the breakdown of complex carbohydrates is restricted to a subset of organisms. A regulatory paradigm for integration of complex polysaccharide breakdown with simple sugar utilization was established in the mammalian gut symbiont Bacteroides thetaiotaomicron, whereby sensing of monomeric fructose regulates catabolism of both fructose and polymeric fructans. We now report that a different regulatory paradigm governs utilization of monomeric arabinose and the arabinose polymer arabinan. We establish that (i) arabinan utilization genes are controlled by a transcriptional activator that responds to arabinan and by a transcriptional repressor that responds to arabinose, (ii) arabinose utilization genes are regulated directly by the arabinose-responding repressor but indirectly by the arabinan-responding activator, and (iii) activation of both arabinan and arabinose utilization genes requires a pleiotropic transcriptional regulator necessary for survival in the mammalian gut. Genomic analysis predicts that this paradigm is broadly applicable to the breakdown of other polysaccharides in both B. thetaiotaomicron and other gut Bacteroides spp. The uncovered mechanism enables regulation of polysaccharide utilization genes in response to both the polysaccharide and its breakdown products. Breakdown of complex polysaccharides derived from "dietary fiber" is achieved by the mammalian gut microbiota. This breakdown creates a critical nutrient source for both the microbiota and its mammalian host. Because the availability of individual polysaccharides fluctuates with variations in the host diet, members of the microbiota strictly control expression of polysaccharide utilization genes. Our findings define a regulatory architecture that controls the breakdown of a polysaccharide by a gut bacterium in response to three distinct signals. This architecture integrates perception of a complex

Comparison of Anaerobic Susceptibility Results Obtained by Different Methods

PubMed Central

Rosenblatt, J. E.; Murray, P. R.; Sonnenwirth, A. C.; Joyce, J. L.

1979-01-01

Susceptibility tests using 7 antimicrobial agents (carbenicillin, chloramphenicol, clindamycin, penicillin, cephalothin, metronidazole, and tetracycline) were run against 35 anaerobes including Bacteroides fragilis (17), other gram-negative bacilli (7), clostridia (5), peptococci (4), and eubacteria (2). Results in triplicate obtained by the microbroth dilution method and the aerobic modification of the broth disk method were compared with those obtained with an agar dilution method using Wilkins-Chalgren agar. Media used in the microbroth dilution method included Wilkins-Chalgren broth, brain heart infusion broth, brucella broth, tryptic soy broth, thioglycolate broth, and Schaedler's broth. A result differing by more than one dilution from the Wilkins-Chalgren agar result was considered a discrepancy, and when there was a change in susceptibility status this was termed a significant discrepancy. The microbroth dilution method using Wilkins-Chalgren broth and thioglycolate broth produced the fewest total discrepancies (22 and 24, respectively), and Wilkins-Chalgren broth, thioglycolate, and Schaedler's broth had the fewest significant discrepancies (6, 5, and 5, respectively). With the broth disk method, there were 15 significant discrepancies, although half of these were with tetracycline, which was the antimicrobial agent associated with the highest number of significant discrepancies (33), considering all of the test methods and media. PMID:464560

34 CFR 108.5 - Compliance obligations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 1 2010-07-01 2010-07-01 false Compliance obligations. 108.5 Section 108.5 Education Regulations of the Offices of the Department of Education OFFICE FOR CIVIL RIGHTS, DEPARTMENT OF EDUCATION... § 108.5 Compliance obligations. (a) The obligation of covered entities to comply with the Act and this...

Selenihalanaerobacter shriftii gen. nov., sp. nov., a halophilic anaerobe from Dead Sea sediments that respires selenate

USGS Publications Warehouse

Switzer, Blum J.; Stolz, J.F.; Oren, A.; Oremland, R.S.

2001-01-01

We isolated an obligately anaerobic halophilic bacterium from the Dead Sea that grew by respiration of selenate. The isolate, designated strain DSSe-1, was a gram-negative, non-motile rod. It oxidized glycerol or glucose to acetate+CO2 with concomitant reduction of selenate to selenite plus elemental selenium. Other electron acceptors that supported anaerobic growth on glycerol were nitrate and trimethylamine-N-oxide; nitrite, arsenate, fumarate, dimethylsulfoxide, thiosulfate, elemental sulfur, sulfite or sulfate could not serve as electron acceptors. Growth on glycerol in the presence of nitrate occurred over a salinity range from 100 to 240 g/l, with an optimum at 210 g/l. Analysis of the 16S rRNA gene sequence suggests that strain DSSe-1 belongs to the order Halanaerobiales, an order of halophilic anaerobes with a fermentative or homoacetogenic metabolism, in which anaerobic respiratory metabolism has never been documented. The highest 16S rRNA sequence similarity (90%) was found with Acetohalobium arabaticum (X89077). On the basis of physiological properties as well as the relatively low homology of 16S rRNA from strain DSSe-1 with known genera, classification in a new genus within the order Halanaerobiales, family Halobacteroidaceae is warranted. We propose the name Selenihalanaerobacter shriftii. Type strain is strain DSSe-1 (ATCC accession number BAA-73).

The Glycolytic Versatility of Bacteroides uniformis CECT 7771 and Its Genome Response to Oligo and Polysaccharides

PubMed Central

Benítez-Páez, Alfonso; Gómez del Pulgar, Eva M.; Sanz, Yolanda

2017-01-01

Bacteroides spp. are dominant components of the phylum Bacteroidetes in the gut microbiota and prosper in glycan enriched environments. However, knowledge of the machinery of specific species isolated from humans (like Bacteroides uniformis) contributing to the utilization of dietary and endogenous sources of glycans and their byproducts is limited. We have used the cutting-edge nanopore-based technology to sequence the genome of B. uniformis CECT 7771, a human symbiont with a proven pre-clinical efficacy on metabolic and immune dysfunctions in obesity animal models. We have also used massive sequencing approaches to distinguish the genome expression patterns in response to carbon sources of different complexity during growth. At genome-wide level, our analyses globally demonstrate that B. uniformis strains exhibit an expanded glycolytic capability when compared with other Bacteroides species. Moreover, by studying the growth and whole-genome expression of B. uniformis CECT 7771 in response to different carbon sources, we detected a differential growth fitness and expression patterns across the genome depending on the carbon source of the culture media. The dietary fibers used exerted different effects on B. uniformis CECT 7771 activating different molecular pathways and, therefore, allowing the production of different metabolite types with potential impact on gut health. The genome and transcriptome analysis of B. uniformis CECT 7771, in response to different carbon sources, shows its high versatility to utilize both dietary and endogenous glycans along with the production of potentially beneficial end products for both the bacterium and the host, pointing to a mechanistic basis of a mutualistic relationship. PMID:28971068

Role of anaerobic bacteria in biological soil disinfestation for elimination of soil-borne plant pathogens in agriculture.

PubMed

Ueki, Atsuko; Kaku, Nobuo; Ueki, Katsuji

2018-06-01

Biological soil disinfestation (BSD) or reductive soil disinfestation (RSD) is an environmental biotechnology to eliminate soil-borne plant pathogens based on functions of indigenous microbes. BSD treatments using different types of organic materials have been reported to effectively control a wide range of plant pathogens. Various studies have shown that development of reducing or anoxic conditions in soil is the most important aspect for effective BSD treatments. Substances such as organic acids, FeS, or phenolic compounds generated in the treated soil have been suggested to contribute to inactivation of pathogens. Additionally, anaerobic bacteria grown in the BSD-treated soil may produce and release enzymes with anti-pathogenic activities in soil. Clone library analyses as well as a next-generation sequence analysis based on 16S rRNA genes have revealed prosperity of obligate anaerobic bacteria from the class Clostridia in differently treated BSD soils. Two anaerobic bacterial strains isolated from BSD-treated soil samples and identified as Clostridium beijerinckii were found to decompose major cell wall polysaccharides of ascomycetous fungi, chitosan and β-1,3-glucan. C. beijerinckii is a species most frequently detected in the clone library analyses for various BSD-treated soils as a closely related species. The two anaerobic isolates severely degraded mycelial cells of the Fusarium pathogen of spinach wilt disease during anaerobic co-incubation of each isolate and the Fusarium pathogen. These reports suggest that antifungal enzymes produced by predominant anaerobic bacteria grown in the BSD-treated soil play important roles to control soil-borne fungal pathogens. Further studies using different bacterial isolates from BSD-treated soils are expected to know their anti-pathogenic abilities.

[Isolation and identification of seven thermophilic and anaerobic bacteria from hot springs in Tengchong Rehai].

PubMed

Lu, Yueqing; Chen, Bo; Liu, Xiaoli; Ji, Xiuling; Wei, Yunlin; Lin, Lianbing

2009-09-01

In order to study the taxonomic characteristic and physiological, biochemical properties of anaerobic bacteria from hot springs in Tengchong Rehai, Yunnan Province, China. Using Hungate anaerobic technique We isolated seven strains from hot springs in Tengchong Rehai, Yunnan province, and analyzed their 16S rRNA gene sequences. The seven isolates were rod-shaped, Gram-negative, obligate anaerobe, and spores formation was not observed. All strains could grow well at 70 degrees C. Growth of strain RH0802 occurred between 60 and 80 degrees C, optimally around 70 degrees C. The pH range for its growth was between 5.5 and 8.5, with an optimum around 7.0. Strain RH0802 grew on a wide range of carbon sources, including glucose, starch, mannitol, mannose, ribose, maltose, cellobiose, xylose, fructose, galactose, xylan and glycerol, but it could not utilize sucrose or pyruvate. 16S rRNA gene phylogenetic analysis showed that the maximum similarity between the five strains and the strains of genus Caldanaerobacter was up to 98%, except RH0804 and RH0806, which reached to 96% and 93%, respectively. The two isolates were presumed to be potential novel species. The GenBank accession numbers of RH0802 to RH0808 were FJ748766, FJ748762, FJ748761, FJ748763, FJ748765, FJ748764 and FJ748767. The results showed that the seven thermophilic anaerobes belonged to the genus Caldanaerobacter.

Evaluation of Bacteroides fragilis GB-124 bacteriophages as novel human-associated faecal indicators in the United States

EPA Science Inventory

Phages infecting human-associated Bacteroides fragilis (GB-124 phages) have been employed in the European Union (EU) to identify human fecal pollution, but their utility for U.S. was unclear. Primary sewage effluent samples were collected seasonally from seven wastewater treatme...

29 CFR 37.21 - How long will the recipient's obligation under the assurance last, and how broad is the obligation?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true How long will the recipient's obligation under the assurance last, and how broad is the obligation? 37.21 Section 37.21 Labor Office of the Secretary of Labor...'s obligation under the assurance last, and how broad is the obligation? (a) Where the WIA Title I...

29 CFR 37.21 - How long will the recipient's obligation under the assurance last, and how broad is the obligation?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 1 2012-07-01 2012-07-01 false How long will the recipient's obligation under the assurance last, and how broad is the obligation? 37.21 Section 37.21 Labor Office of the Secretary of Labor...'s obligation under the assurance last, and how broad is the obligation? (a) Where the WIA Title I...

29 CFR 37.21 - How long will the recipient's obligation under the assurance last, and how broad is the obligation?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 1 2014-07-01 2013-07-01 true How long will the recipient's obligation under the assurance last, and how broad is the obligation? 37.21 Section 37.21 Labor Office of the Secretary of Labor...'s obligation under the assurance last, and how broad is the obligation? (a) Where the WIA Title I...

29 CFR 37.21 - How long will the recipient's obligation under the assurance last, and how broad is the obligation?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 1 2011-07-01 2011-07-01 false How long will the recipient's obligation under the assurance last, and how broad is the obligation? 37.21 Section 37.21 Labor Office of the Secretary of Labor...'s obligation under the assurance last, and how broad is the obligation? (a) Where the WIA Title I...

29 CFR 37.21 - How long will the recipient's obligation under the assurance last, and how broad is the obligation?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 1 2013-07-01 2013-07-01 false How long will the recipient's obligation under the assurance last, and how broad is the obligation? 37.21 Section 37.21 Labor Office of the Secretary of Labor...'s obligation under the assurance last, and how broad is the obligation? (a) Where the WIA Title I...

Structure and sequence analyses of Bacteroides proteins BVU_4064 and BF1687 reveal presence of two novel predominantly-beta domains, predicted to be involved in lipid and cell surface interactions

DOE PAGES

Natarajan, Padmaja; Punta, Marco; Kumar, Abhinav; ...

2015-01-16

N-terminal domains of BVU_4064 and BF1687 proteins from Bacteroides vulgatus and Bacteroides fragilis respectively are members of the Pfam family PF12985 (DUF3869). Proteins containing a domain from this family can be found in most Bacteroides species and, in large numbers, in all human gut microbiome samples. Both BVU_4064 and BF1687 proteins have a consensus lipobox motif implying they are anchored to the membrane, but their functions are otherwise unknown. The C-terminal half of BVU_4064 is assigned to protein family PF12986 (DUF3870); the equivalent part of BF1687 was unclassified.

Probabilistic analysis showing that a combination of bacteroides and methanobrevibacter source tracking markers is effective for identifying waters contaminated by human fecal pollution

USGS Publications Warehouse

Johnston, Christopher; Byappanahalli, Muruleedhara N.; Gibson, Jacqueline MacDonald; Ufnar, Jennifer A.; Whitman, Richard L.; Stewart, Jill R.

2013-01-01

Microbial source tracking assays to identify sources of waterborne contamination typically target genetic markers of host-specific microorganisms. However, no bacterial marker has been shown to be 100% host-specific, and cross-reactivity has been noted in studies evaluating known source samples. Using 485 challenge samples from 20 different human and animal fecal sources, this study evaluated microbial source tracking markers including the Bacteroides HF183 16S rRNA, M. smithii nifH, and Enterococcus esp gene targets that have been proposed as potential indicators of human fecal contamination. Bayes' Theorem was used to calculate the conditional probability that these markers or a combination of markers can correctly identify human sources of fecal pollution. All three human-associated markers were detected in 100% of the sewage samples analyzed. Bacteroides HF183 was the most effective marker for determining whether contamination was specifically from a human source, and greater than 98% certainty that contamination was from a human source was shown when both Bacteroides HF183 and M. smithii nifH markers were present. A high degree of certainty was attained even in cases where the prior probability of human fecal contamination was as low as 8.5%. The combination of Bacteroides HF183 and M. smithii nifH source tracking markers can help identify surface waters impacted by human fecal contamination, information useful for prioritizing restoration activities or assessing health risks from exposure to contaminated waters.

Anaerobic Cysteine Degradation and Potential Metabolic Coordination in Salmonella enterica and Escherichia coli

PubMed Central

Loddeke, Melissa; Schneider, Barbara; Oguri, Tamiko; Mehta, Iti; Xuan, Zhenyu

2017-01-01

ABSTRACT Salmonella enterica has two CyuR-activated enzymes that degrade cysteine, i.e., the aerobic CdsH and an unidentified anaerobic enzyme; Escherichia coli has only the latter. To identify the anaerobic enzyme, transcript profiling was performed for E. coli without cyuR and with overexpressed cyuR. Thirty-seven genes showed at least 5-fold changes in expression, and the cyuPA (formerly yhaOM) operon showed the greatest difference. Homology suggested that CyuP and CyuA represent a cysteine transporter and an iron-sulfur-containing cysteine desulfidase, respectively. E. coli and S. enterica ΔcyuA mutants grown with cysteine generated substantially less sulfide and had lower growth yields. Oxygen affected the CyuR-dependent genes reciprocally; cyuP-lacZ expression was greater anaerobically, whereas cdsH-lacZ expression was greater aerobically. In E. coli and S. enterica, anaerobic cyuP expression required cyuR and cysteine and was induced by l-cysteine, d-cysteine, and a few sulfur-containing compounds. Loss of either CyuA or RidA, both of which contribute to cysteine degradation to pyruvate, increased cyuP-lacZ expression, which suggests that CyuA modulates intracellular cysteine concentrations. Phylogenetic analysis showed that CyuA homologs are present in obligate and facultative anaerobes, confirming an anaerobic function, and in archaeal methanogens and bacterial acetogens, suggesting an ancient origin. Our results show that CyuA is the major anaerobic cysteine-catabolizing enzyme in both E. coli and S. enterica, and it is proposed that anaerobic cysteine catabolism can contribute to coordination of sulfur assimilation and amino acid synthesis. IMPORTANCE Sulfur-containing compounds such as cysteine and sulfide are essential and reactive metabolites. Exogenous sulfur-containing compounds can alter the thiol landscape and intracellular redox reactions and are known to affect several cellular processes, including swarming motility, antibiotic sensitivity, and

Use of abundance ratios of somatic coliphages and bacteriophages of Bacteroides thetaiotaomicron GA17 for microbial source identification.

PubMed

Muniesa, Maite; Lucena, Francisco; Blanch, Anicet R; Payán, Andrey; Jofre, Juan

2012-12-01

Water contaminated with human faeces is a risk to human health and management of water bodies can be improved by determining the sources of faecal pollution. Field studies show that existing methods are insufficient and that different markers are required. This study proposes the combined use of two microbial indicators, the concentrations of which are presented as ratios. This provides a more reliable approach to identifying faecal sources as it avoids variation due to treatment or ageing of the contamination. Among other indicators, bacteriophages have been proposed as rapid and cheap indicators of faecal pollution. Samples analysed in this study were derived from wastewater treatment plants (raw sewage, secondary and tertiary effluents and raw sewage sludge) river water, seawater and animal related wastewater. The abundance ratios of faecal coliforms and Bacteroides phages, either strain RYC2056 (non-specific for faecal origin) or strain GA17 (specific for human pollution), and among somatic coliphages and phages infecting both Bacteroides strains, were evaluated. The results indicate that the ratio of somatic coliphages and phages infecting Bacteroides strain GA17, which is specific to human faecal sources, provides a robust method for discriminating samples, even those presenting different levels and ages of pollution, and allows samples polluted with human faeces to be distinguished from those containing animal faecal pollution. This method allows the generation of numerical data that can be further applied to numerical methods for faecal pollution discrimination. Copyright © 2012 Elsevier Ltd. All rights reserved.

Grandparents' entitlements and obligations.

PubMed

Draper, Heather

2013-07-01

In this article, it is argued that grandparents' obligations originate from parental obligations (i.e from the relationship they have with their children, the parents of their grandchildren) and not from the role of grandparent per se, and any entitlements flow from the extent to which these obligations are met. The position defended is, therefore, that grandparents qua grandparents are not entitled to form or continue relationships with their grandchildren. A continuation of grandparent-grandchildren relationships may be in the interests of children, but the grandparental nature of the relationship is not decisive. What counts is the extent to which relationships children have with any adults who are not their parents are is significant to them. Sometimes, however, grandparents become parents or co-parents of their grandchildren. They then gain parental rights, and as such are as entitled, ceteris parius, as any parent to expect their relationship with the child to continue. The issue of grandparents' entitlements can come to the fore when parents separate, and grandparents are unhappy with the access they have to their grandchildren. Grandparents' obligations may become a particular issue when parents die, struggle, or fail to care for their children. This article focuses particularly on these kinds of circumstances. © 2013 John Wiley & Sons Ltd.

GRANDPARENTS' ENTITLEMENTS AND OBLIGATIONS

PubMed Central

Draper, Heather

2013-01-01

In this article, it is argued that grandparents' obligations originate from parental obligations (i.e from the relationship they have with their children, the parents of their grandchildren) and not from the role of grandparent per se, and any entitlements flow from the extent to which these obligations are met. The position defended is, therefore, that grandparents qua grandparents are not entitled to form or continue relationships with their grandchildren. A continuation of grandparent-grandchildren relationships may be in the interests of children, but the grandparental nature of the relationship is not decisive. What counts is the extent to which relationships children have with any adults who are not their parents are is significant to them. Sometimes, however, grandparents become parents or co-parents of their grandchildren. They then gain parental rights, and as such are as entitled, ceteris parius, as any parent to expect their relationship with the child to continue. The issue of grandparents' entitlements can come to the fore when parents separate, and grandparents are unhappy with the access they have to their grandchildren. Grandparents' obligations may become a particular issue when parents die, struggle, or fail to care for their children. This article focuses particularly on these kinds of circumstances. PMID:23718643

31 CFR 149.3 - Maximum obligation limitation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 31 Money and Finance: Treasury 1 2014-07-01 2014-07-01 false Maximum obligation limitation. 149.3 Section 149.3 Money and Finance: Treasury Regulations Relating to Money and Finance MONETARY OFFICES, DEPARTMENT OF THE TREASURY CALCULATION OF MAXIMUM OBLIGATION LIMITATION § 149.3 Maximum obligation limitation...

10 CFR 600.20 - Maximum DOE obligation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Maximum DOE obligation. 600.20 Section 600.20 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS FINANCIAL ASSISTANCE RULES General § 600.20 Maximum DOE obligation. (a) The maximum DOE obligation to the recipient is— (1) For monetary awards, the...

Comparison of randomly cloned and whole genomic DNA probes for the detection of Porphyromonas gingivalis and Bacteroides forsythus

PubMed Central

Wong, M.; DiRienzo, J.M.; Lai, C.-H.; Listgarten, M. A.

2012-01-01

Whole genomic and randomly-cloned DNA probes for two fastidious periodontal pathogens, Porphyromonas gingivalis and Bacteroides forsythus were labeled with digoxigenin and detected by a colorimetric method. The specificity and sensitivity of the whole genomic and cloned probes were compared. The cloned probes were highly specific compared to the whole genomic probes. A significant degree of cross-reactivity with Bacteroides species. Capnocytophaga sp. and Prevotella sp. was observed with the whole genomic probes. The cloned probes were less sensitive than the whole genomic probes and required at least 106 target cells or a minimum of 10 ng of target DNA to be detected during hybridization. Although a ten-fold increase in sensitivity was obtained with the whole genomic probes, cross-hybridization to closely related species limits their reliability in identifying target bacteria in subgingival plaque samples. PMID:8636873

46 CFR 287.20 - Obligation of deposits.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 8 2010-10-01 2010-10-01 false Obligation of deposits. 287.20 Section 287.20 Shipping... OPERATORS ESTABLISHMENT OF CONSTRUCTION RESERVE FUNDS § 287.20 Obligation of deposits. (a) Time for obligation. Within three years from the date of any deposit in a construction reserve fund, unless extension...

Increased Gut Redox and Depletion of Anaerobic and Methanogenic Prokaryotes in Severe Acute Malnutrition

PubMed Central

Million, Matthieu; Tidjani Alou, Maryam; Khelaifia, Saber; Bachar, Dipankar; Lagier, Jean-Christophe; Dione, Niokhor; Brah, Souleymane; Hugon, Perrine; Lombard, Vincent; Armougom, Fabrice; Fromonot, Julien; Robert, Catherine; Michelle, Caroline; Diallo, Aldiouma; Fabre, Alexandre; Guieu, Régis; Sokhna, Cheikh; Henrissat, Bernard; Parola, Philippe; Raoult, Didier

2016-01-01

Severe acute malnutrition (SAM) is associated with inadequate diet, low levels of plasma antioxidants and gut microbiota alterations. The link between gut redox and microbial alterations, however, remains unexplored. By sequencing the gut microbiomes of 79 children of varying nutritional status from three centers in Senegal and Niger, we found a dramatic depletion of obligate anaerobes in malnutrition. This was confirmed in an individual patient data meta-analysis including 107 cases and 77 controls from 5 different African and Asian countries. Specifically, several species of the Bacteroidaceae, Eubacteriaceae, Lachnospiraceae and Ruminococceae families were consistently depleted while Enterococcus faecalis, Escherichia coli and Staphylococcus aureus were consistently enriched. Further analyses on our samples revealed increased fecal redox potential, decreased total bacterial number and dramatic Methanobrevibacter smithii depletion. Indeed, M. smithii was detected in more than half of the controls but in none of the cases. No causality was demonstrated but, based on our results, we propose a unifying theory linking microbiota specificity, lacking anaerobes and archaea, to low antioxidant nutrients, and lower food conversion. PMID:27183876

Genetically modified "obligate" anaerobic Salmonella typhimurium as a therapeutic strategy for neuroblastoma.

PubMed

Guo, Zhu-Ling; Yu, Bin; Ning, Bo-Tao; Chan, Shing; Lin, Qiu-Bin; Li, James Chun-Bong; Huang, Jian-Dong; Chan, Godfrey Chi-Fung

2015-08-19

Neuroblastoma currently has poor prognosis, therefore we proposed a new strategy by targeting neuroblastoma with genetically engineered anaerobic Salmonella (Sal-YB1). Nude and nonobese diabetic-severe combined immunodeficiency (NOD-SCID) orthotopic mouse models were used, and Sal-YB1 was administered via tail vein. The therapeutic effectiveness, bio-safety, and mechanisms were studied. No mice died of therapy-related complications. Tumor size reduction was 70 and 30% in nude and NOD-SCID mice, respectively. No Salmonella was detected in the urine; 75% mice had positive stool culture if diaminopimelic acid was added, but all turned negative subsequently. Tumor tissues had more Sal-YB1 infiltration, necrosis, and shrinkage in Sal-YB1-treated mice. Significantly higher expression of TLR4, TNF-stimulated gene 6 protein (TSG6), and cleaved caspase 1, 3, 8, and 9 was found in the tumor masses of the Sal-YB1-treated group with a decrease of interleukin 1 receptor-associated kinase (IRAK) and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha (IκBα). There was a high release of TNFα both in human macrophages and mouse tumor tissues with Sal-YB1 treatment. The antitumor effect of the supernatant derived from macrophages treated with Sal-YB1 could be reversed with TNFα and pan-caspase inhibitors. This new approach in targeting neuroblastoma by bio-engineered Salmonella with the assistance of macrophages indirectly may have a clinical therapeutic impact in the future.

Improved HF183 reverse primer and probe for greater analytical sensitivity of human Bacteroides in the environment

EPA Science Inventory

Background: Numerous indicators have been used to assess the presence of fecal pollution, many relying on molecular methods such as qPCR. One of the targets frequently used, the human-associated Bacteroides 16s rRNA region, has several assays in current usage. These assays vary...

Antimicrobial susceptibility of clinically isolated anaerobic bacteria in a University Hospital Centre Split, Croatia in 2013.

PubMed

Novak, Anita; Rubic, Zana; Dogas, Varja; Goic-Barisic, Ivana; Radic, Marina; Tonkic, Marija

2015-02-01

Anaerobic bacteria play a significant role in many endogenous polymicrobial infections. Since antimicrobial resistance among anaerobes has increased worldwide, it is useful to provide local susceptibility data to guide empirical therapy. The present study reports recent data on the susceptibility of clinically relevant anaerobes in a University Hospital Centre (UHC) Split, Croatia. A total of 63 Gram-negative and 59 Gram-positive anaerobic clinical isolates from various body sites were consecutively collected from January to December 2013. Antimicrobial susceptibility testing was performed using standardized methods and interpreted using EUCAST criteria. Patient's clinical and demographic data were recorded by clinical microbiologist. Among 35 isolates of Bacteroides spp., 97.1% were resistant to penicillin (PCN), 5.7% to amoxicillin/clavulanic acid (AMC), 8.6% to piperacillin/tazobactam (TZP), 29.0% to clindamycin (CLI) and 2.9% to metronidazole (MZ). Percentages of susceptible strains to imipenem (IPM), meropenem (MEM) and ertapenem (ETP) were 94.3. Resistance of other Gram-negative bacilli was 76.0% to PCN, 8.0% to AMC, 12.0% to TZP, 28.0% to CLI and 8% to MZ. All other Gram-negative strains were fully susceptible to MEM and ETP, while 96.0% were susceptible to IPM. Clostridium spp. isolates were 100% susceptible to all tested antibiotics except to CLI (two of four tested isolates were resistant). Propionibacterium spp. showed resistance to CLI in 4.3%, while 100% were resistant to MZ. Among other Gram-positive bacilli, 18.2% were resistant to PCN, 9.1% to CLI and 54.5% to MZ, while 81.8% of isolates were susceptible to carbapenems. Gram-positive cocci were 100% susceptible to all tested antimicrobials except to MZ, where 28.6% of resistant strains were recorded. Abdomen was the most common source of isolates (82.5%). The most prevalent types of infection were abscess (22.1%), sepsis (14.8%), appendicitis (13.9%) and peritonitis (6.6%). Twenty four patients (19

Cancer Moonshot Funding Obligations FY 2017

Cancer.gov

NCI reports Cancer Moonshot obligations by funding mechanism. See obligations for Moonshot grants, intramural research, and contracts, including the number of grant awards, funding amounts, and percentages by mechanism of the total Cancer Moonshot budget.

Human Bacteroides and total coliforms as indicators of recent combined sewer overflows and rain events in urban creeks

USGS Publications Warehouse

McGinnis, Shannon; Spencer, Susan K.; Firnstahl, Aaron; Stokdyk, Joel; Borchardt, Mark A.; McCarthy, David; Murphy, Heather

2018-01-01

Combined sewer overflows (CSOs) are a known source of human fecal pollution and human pathogens in urban water bodies, which may present a significant public health threat. To monitor human fecal contamination in water, bacterial fecal indicator organisms (FIOs) are traditionally used. However, because FIOs are not specific to human sources and do not correlate with human pathogens, alternative fecal indicators detected using qPCR are becoming of interest to policymakers. For this reason, this study measured correlations between the number and duration of CSOs and mm of rainfall, concentrations of traditional FIOs and alternative indicators, and the presence of human pathogens in two urban creeks. Samples were collected May–July 2016 and analyzed for concentrations of FIOs (total coliforms and E. coli) using membrane filtration as well as for three alternative fecal indicators (human Bacteroides HF183 marker, human polyomavirus (HPoV), pepper mild mottle virus (PMMoV)) and nine human pathogens using qPCR. Four of the nine pathogens analyzed were detected at these sites including adenovirus, Enterohemorrhagic E. coli, norovirus, and Salmonella. Among all indicators studied, human Bacteroides and total coliforms were significantly correlated with recent CSO and rainfall events, while E. coli, PMMoV, and HPoV did not show consistent significant correlations. Further, human Bacteroides were a more specific indicator, while total coliforms were a more sensitive indicator of CSO and rainfall events. Results may have implications for the use and interpretation of these indicators in future policy or monitoring programs.

Human Bacteroides and total coliforms as indicators of recent combined sewer overflows and rain events in urban creeks.

PubMed

McGinnis, Shannon; Spencer, Susan; Firnstahl, Aaron; Stokdyk, Joel; Borchardt, Mark; McCarthy, David T; Murphy, Heather M

2018-07-15

Combined sewer overflows (CSOs) are a known source of human fecal pollution and human pathogens in urban water bodies, which may present a significant public health threat. To monitor human fecal contamination in water, bacterial fecal indicator organisms (FIOs) are traditionally used. However, because FIOs are not specific to human sources and do not correlate with human pathogens, alternative fecal indicators detected using qPCR are becoming of interest to policymakers. For this reason, this study measured correlations between the number and duration of CSOs and mm of rainfall, concentrations of traditional FIOs and alternative indicators, and the presence of human pathogens in two urban creeks. Samples were collected May-July 2016 and analyzed for concentrations of FIOs (total coliforms and E. coli) using membrane filtration as well as for three alternative fecal indicators (human Bacteroides HF183 marker, human polyomavirus (HPoV), pepper mild mottle virus (PMMoV)) and nine human pathogens using qPCR. Four of the nine pathogens analyzed were detected at these sites including adenovirus, Enterohemorrhagic E. coli, norovirus, and Salmonella. Among all indicators studied, human Bacteroides and total coliforms were significantly correlated with recent CSO and rainfall events, while E. coli, PMMoV, and HPoV did not show consistent significant correlations. Further, human Bacteroides were a more specific indicator, while total coliforms were a more sensitive indicator of CSO and rainfall events. Results may have implications for the use and interpretation of these indicators in future policy or monitoring programs. Copyright © 2018 Elsevier B.V. All rights reserved.

Accelerated anaerobic hydrolysis rates under a combination of intermittent aeration and anaerobic conditions.

PubMed

Jensen, T R; Lastra Milone, T; Petersen, G; Andersen, H R

2017-04-01

Anaerobic hydrolysis in activated return sludge was investigated in laboratory scale experiments to find if intermittent aeration would accelerate anaerobic hydrolysis rates compared to anaerobic hydrolysis rates under strict anaerobic conditions. The intermittent reactors were set up in a 240 h experiment with intermittent aeration (3 h:3 h) in a period of 24 h followed by a subsequent anaerobic period of 24 h in a cycle of 48 h which was repeated five times during the experiment. The anaerobic reactors were kept under strict anaerobic conditions in the same period (240 h). Two methods for calculating hydrolysis rates based on soluble chemical oxygen demand were compared. Two-way analysis of variance with the Bonferroni post-test was performed in order to register any significant difference between reactors with intermittent aeration and strictly anaerobic conditions respectively. The experiment demonstrated a statistically significant difference in favor of the reactors with intermittent aeration showing a tendency towards accelerated anaerobic hydrolysis rates due to application of intermittent aeration. The conclusion of the work is thus that intermittent aeration applied in the activated return sludge process can improve the treatment capacity further in full scale applications.

46 CFR 298.30 - Nature and content of Obligations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 8 2011-10-01 2011-10-01 false Nature and content of Obligations. 298.30 Section 298.30 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VESSEL FINANCING ASSISTANCE OBLIGATION GUARANTEES Documentation § 298.30 Nature and content of Obligations. (a) Single page. An Obligation, in the...

46 CFR 298.30 - Nature and content of Obligations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 8 2010-10-01 2010-10-01 false Nature and content of Obligations. 298.30 Section 298.30 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VESSEL FINANCING ASSISTANCE OBLIGATION GUARANTEES Documentation § 298.30 Nature and content of Obligations. (a) Single page. An Obligation, in the...

46 CFR 298.30 - Nature and content of Obligations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 8 2012-10-01 2012-10-01 false Nature and content of Obligations. 298.30 Section 298.30 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VESSEL FINANCING ASSISTANCE OBLIGATION GUARANTEES Documentation § 298.30 Nature and content of Obligations. (a) Single page. An Obligation, in the...

46 CFR 298.30 - Nature and content of Obligations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 8 2014-10-01 2014-10-01 false Nature and content of Obligations. 298.30 Section 298.30 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VESSEL FINANCING ASSISTANCE OBLIGATION GUARANTEES Documentation § 298.30 Nature and content of Obligations. (a) Single page. An Obligation, in the...

46 CFR 298.30 - Nature and content of Obligations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 8 2013-10-01 2013-10-01 false Nature and content of Obligations. 298.30 Section 298.30 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VESSEL FINANCING ASSISTANCE OBLIGATION GUARANTEES Documentation § 298.30 Nature and content of Obligations. (a) Single page. An Obligation, in the...

7 CFR 400.167 - Limitations on Corporation's obligations.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 6 2013-01-01 2013-01-01 false Limitations on Corporation's obligations. 400.167... INSURANCE CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE REGULATIONS Reinsurance Agreement... Corporation's obligations. The Agreement will include the following among the limitations on the obligations...

7 CFR 400.167 - Limitations on Corporation's obligations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 6 2011-01-01 2011-01-01 false Limitations on Corporation's obligations. 400.167... INSURANCE CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE REGULATIONS Reinsurance Agreement... Corporation's obligations. The Agreement will include the following among the limitations on the obligations...

7 CFR 400.167 - Limitations on Corporation's obligations.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 6 2012-01-01 2012-01-01 false Limitations on Corporation's obligations. 400.167... INSURANCE CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE REGULATIONS Reinsurance Agreement... Corporation's obligations. The Agreement will include the following among the limitations on the obligations...

7 CFR 400.167 - Limitations on Corporation's obligations.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 6 2014-01-01 2014-01-01 false Limitations on Corporation's obligations. 400.167... INSURANCE CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE REGULATIONS Reinsurance Agreement... Corporation's obligations. The Agreement will include the following among the limitations on the obligations...

7 CFR 400.167 - Limitations on Corporation's obligations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Limitations on Corporation's obligations. 400.167... INSURANCE CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE REGULATIONS Reinsurance Agreement... Corporation's obligations. The Agreement will include the following among the limitations on the obligations...

Anaerobic bacteria

MedlinePlus

Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria ... Brook I. Diseases caused by non-spore-forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman-Cecil ...

Microbiological analysis of infected root canals from symptomatic and asymptomatic teeth with periapical periodontitis and the antimicrobial susceptibility of some isolated anaerobic bacteria.

PubMed

Jacinto, R C; Gomes, B P F A; Ferraz, C C R; Zaia, A A; Filho, F J Souza

2003-10-01

The purpose of the present study was to investigate the correlation between the composition of the bacterial flora isolated from infected root canals of teeth with apical periodontitis with the presence of clinical signs and symptoms, and to test the antibiotic susceptibility of five anaerobic bacteria mostly commonly found in the root canals of symptomatic teeth against various substances using the E-test. Microbial samples were taken from 48 root canals, 29 symptomatic and 19 asymptomatic, using adequate techniques. A total of 218 cultivable isolates were recovered from 48 different microbial species and 19 different genera. Root canals from symptomatic teeth harbored more obligate anaerobes and a bigger number of bacterial species than the asymptomatic teeth. More than 70% of the bacterial isolates were strict anaerobes. Statistical analysis used a Pearson Chi-squared test or a one-sided Fisher's Exact test as appropriate. Suggested relationships were found between specific microorganisms, especially gram-negative anaerobes, and the presence of spontaneous or previous pain, tenderness to percussion, pain on palpation and swelling amoxicillin, amoxicillin + clavulanate and cephaclor were effective against all the strains tested. The lowest susceptibility rate was presented by Prevotella intermedia/nigrescens against Penicillin G. Our results suggested that specific bacteria are associated with endodontic symptoms of infected teeth with periapical periodontitis and the majority of the anaerobic bacterial species tested were susceptible to all antibiotics studied.

Identification and Use of the Putative Bacteroides ovatus Xylanase Promoter for the Inducible Production of Recombinant Human Proteins

USDA-ARS?s Scientific Manuscript database

The use of genetically modified bacteria to deliver biologically active molecules directly to the gut has become an increasingly attractive area of investigation. The challenge of regulation of production of the therapeutic molecule and colonization of the bowel led us to investigate Bacteroides ov...

Characterization of an activity from the strict anaerobe Roseburia cecicola that degrades DNA when exposed to air.

PubMed Central

O'Connor, L T; Savage, D C

1993-01-01

Roseburia cecicola is an obligately anaerobic bacterium that is extremely sensitive to oxygen. Genomic DNA isolated from cells exposed to air for even a brief period (< 5 min) is partially degraded, while DNA extracted from cells maintained in an anaerobic environment remains intact. Cells exposed to air for longer and longer periods yield DNA which is progressively degraded into fragments with decreasing sizes. Oxygen toxicity for this anaerobe appears to result, at least in part, from degradation of its genomic DNA. Cell lysates of the organism exhibited a similar ability to degrade exogenous sources of DNA when assayed in vitro under aerobic conditions. A substance that degrades both DNA and RNA when incubated aerobically was partially purified from such lysates. It has an approximate molecular weight of 2,800 and is unlikely to be a protein. It requires a reducing agent for activity and can be inhibited by catalase and peroxidase but not superoxide dismutase. The rate at which it degrades DNA in vitro can be enhanced by temperatures above 37 degrees C or by oxygen at partial pressures above atmospheric pressure. These results suggest that this substance degrades nucleic acids by a mechanism involving oxygen radicals. Images PMID:8335626

NCI & Division Obligations

Cancer.gov

Displays obligations for grants, contracts, training fellowships, intramural research, and management and support, including the number of grant awards, funding amounts, and percent of the total NCI budget.

31 CFR 1024.311 - Filing obligations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... CRIMES ENFORCEMENT NETWORK, DEPARTMENT OF THE TREASURY RULES FOR MUTUAL FUNDS Reports Required To Be Made By Mutual Funds § 1024.311 Filing obligations. Refer to § 1010.311 of this chapter for reports of transactions in currency filing obligations for mutual funds. ...

43 CFR 10005.8 - Mitigation obligations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Mitigation obligations. 10005.8 Section... MITIGATION AND CONSERVATION COMMISSION POLICIES AND PROCEDURES FOR DEVELOPING AND IMPLEMENTING THE COMMISSION'S MITIGATION AND CONSERVATION PLAN § 10005.8 Mitigation obligations. While the Act authorizes the...

43 CFR 10005.8 - Mitigation obligations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Mitigation obligations. 10005.8 Section... MITIGATION AND CONSERVATION COMMISSION POLICIES AND PROCEDURES FOR DEVELOPING AND IMPLEMENTING THE COMMISSION'S MITIGATION AND CONSERVATION PLAN § 10005.8 Mitigation obligations. While the Act authorizes the...

43 CFR 10005.8 - Mitigation obligations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Mitigation obligations. 10005.8 Section... MITIGATION AND CONSERVATION COMMISSION POLICIES AND PROCEDURES FOR DEVELOPING AND IMPLEMENTING THE COMMISSION'S MITIGATION AND CONSERVATION PLAN § 10005.8 Mitigation obligations. While the Act authorizes the...

43 CFR 10005.8 - Mitigation obligations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Mitigation obligations. 10005.8 Section... MITIGATION AND CONSERVATION COMMISSION POLICIES AND PROCEDURES FOR DEVELOPING AND IMPLEMENTING THE COMMISSION'S MITIGATION AND CONSERVATION PLAN § 10005.8 Mitigation obligations. While the Act authorizes the...

Natranaerobaculum magadiense gen. nov., sp. nov., an anaerobic, alkalithermophilic bacterium from soda lake sediment.

PubMed

Zavarzina, Daria G; Zhilina, Tatyana N; Kuznetsov, Boris B; Kolganova, Tatyana V; Osipov, Georgy A; Kotelev, Mikhail S; Zavarzin, Georgy A

2013-12-01

An obligately alkaliphilic, anaerobic, thermo- and halotolerant, spore-forming bacterium was isolated from sediments of soda lake Magadi (Kenya) and designated strain Z-1001(T). Cells of strain Z-1001(T) were straight, Gram-positive rods, slowly motile. Strain Z-1001(T) was found to be an obligate anaerobe. It grew within a pH range from 7.5 to 10.7 with an optimum at 9.25-9.5 (at 40 °C), a temperature range from 20 to 57 °C with an optimum at 45-50 °C, and a NaCl concentration range from 0 to 1.55 M with an optimum at 1.2-1.4 M. Peptides, such as meat and yeast extracts, peptone and tryptone, were fermented by Z-1001(T). Carbohydrates did not support growth. With yeast extract as an electron donor, strain Z-1001(T) reduced S(2)O(3)(2-), NO(-)(3), AsO(3-)(4), Fe(III) citrate and anthraquinone-2,6-disulfonate (AQDS) as electron acceptors. The isolate was able to grow oligotrophically with a very small amount of yeast extract: 0.03 g l(-1). The main fatty acids were C16 : 0, C16 : 1ω7c, C18 : 0 and C18 : 1ω9. The DNA G+C content of the isolate was 35.6 mol%. 16S rRNA gene sequence analysis showed that strain Z-1001(T) is a member of family Natranaerobiaceae, clustering with the type strain of Natranaerobius thermophilus (95.8-96.0 % sequence similarity). On the basis of physiological and phylogenetic data it is proposed that strain Z-1001(T) ( = DSM 24923(T) = VKM B-2666(T)) represents a novel genus and species, Natranaerobaculum magadiense gen. nov., sp. nov.

24 CFR 891.755 - Obligations of the family.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Obligations of the family. 891.755... the Elderly and Persons with Disabilities Section 202 Projects for the Nonelderly Handicapped Families and Individuals-Section 162 Assistance § 891.755 Obligations of the family. The obligations of the...

24 CFR 891.755 - Obligations of the family.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Obligations of the family. 891.755... the Elderly and Persons with Disabilities Section 202 Projects for the Nonelderly Handicapped Families and Individuals-Section 162 Assistance § 891.755 Obligations of the family. The obligations of the...

31 CFR 1026.311 - Filing obligations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... INTRODUCING BROKERS IN COMMODITIES Reports Required To Be Made by Futures Commission Merchants and Introducing Brokers in Commodities § 1026.311 Filing obligations. Refer to § 1010.311 of this chapter for reports of transactions in currency filing obligations for futures commission merchants and introducing brokers in...

Regulated expression of polysaccharide utilization and capsular biosynthesis loci in biofilm and planktonic Bacteroides thetaiotaomicron during growth in chemostats

USDA-ARS?s Scientific Manuscript database

Bacteroides thetaiotaomicron is a prominent member of the human distal gut microbiota that specializes in breaking down diet and host-derived polysaccharides. While polysaccharide utilization has been well studied in B. thetaiotaomicron, other aspects of its behavior are less well characterized, in...

24 CFR 891.615 - Obligations of the family.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Obligations of the family. 891.615 Section 891.615 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT... 8 Assistance § 891.615 Obligations of the family. The obligations of the family are provided in...

24 CFR 891.615 - Obligations of the family.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Obligations of the family. 891.615 Section 891.615 Housing and Urban Development Regulations Relating to Housing and Urban Development... 8 Assistance § 891.615 Obligations of the family. The obligations of the family are provided in...

12 CFR 997.5 - Termination of the obligation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Termination of the obligation. 997.5 Section 997.5 Banks and Banking FEDERAL HOUSING FINANCE BOARD NON-BANK SYSTEM ENTITIES RESOLUTION FUNDING CORPORATION OBLIGATIONS OF THE BANKS § 997.5 Termination of the obligation. (a) Generally. The Banks...

24 CFR 213.266a - Insurance fund obligations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Insurance fund obligations. 213... Insurance fund obligations. A mortgage endorsed for insurance under section 213 of the Act shall be the obligation either of the Cooperative Management Housing Insurance Fund or of the General Insurance Fund. The...

Evolution of Molybdenum Nitrogenase during the Transition from Anaerobic to Aerobic Metabolism

PubMed Central

Boyd, Eric S.; Costas, Amaya M. Garcia; Hamilton, Trinity L.; Mus, Florence

2015-01-01

ABSTRACT Molybdenum nitrogenase (Nif), which catalyzes the reduction of dinitrogen to ammonium, has modulated the availability of fixed nitrogen in the biosphere since early in Earth's history. Phylogenetic evidence indicates that oxygen (O2)-sensitive Nif emerged in an anaerobic archaeon and later diversified into an aerobic bacterium. Aerobic bacteria that fix N2 have adapted a number of strategies to protect Nif from inactivation by O2, including spatial and temporal segregation of Nif from O2 and respiratory consumption of O2. Here we report the complement of Nif-encoding genes in 189 diazotrophic genomes. We show that the evolution of Nif during the transition from anaerobic to aerobic metabolism was accompanied by both gene recruitment and loss, resulting in a substantial increase in the number of nif genes. While the observed increase in the number of nif genes and their phylogenetic distribution are strongly correlated with adaptation to utilize O2 in metabolism, the increase is not correlated with any of the known O2 protection mechanisms. Rather, gene recruitment appears to have been in response to selective pressure to optimize Nif synthesis to meet fixed N demands associated with aerobic productivity and to more efficiently regulate Nif under oxic conditions that favor protein turnover. Consistent with this hypothesis, the transition of Nif from anoxic to oxic environments is associated with a shift from posttranslational regulation in anaerobes to transcriptional regulation in obligate aerobes and facultative anaerobes. Given that fixed nitrogen typically limits ecosystem productivity, our observations further underscore the dynamic interplay between the evolution of Earth's oxygen, nitrogen, and carbon biogeochemical cycles. IMPORTANCE Molybdenum nitrogenase (Nif), which catalyzes the reduction of dinitrogen to ammonium, has modulated the availability of fixed nitrogen in the biosphere since early in Earth's history. Nif emerged in an anaerobe and

Two Multidrug-Resistant Clinical Isolates of Bacteroides fragilis Carry a Novel Metronidazole Resistance nim Gene (nimJ)

PubMed Central

Veeranagouda, Yaligara; Hsi, Justin; Meggersee, Rosemary; Abratt, Valerie; Wexler, Hannah M.

2013-01-01

Two multidrug-resistant Bacteroides fragilis clinical isolates contain and express a novel nim gene, nimJ, that is not recognized by the “universal” nim primers and can confer increased resistance to metronidazole when introduced into a susceptible strain on a multicopy plasmid. HMW615, an appendiceal isolate, contains at least two copies of nimJ on its genome, while HMW616, an isolate from a patient with sepsis, contains one genomic copy of nimJ. B. fragilis NimJ is phylogenetically closer to Prevotella baroniae NimI and Clostridium botulinum NimA than to the other known Bacteroides Nim proteins. The predicted protein structure of NimJ, based on fold recognition analysis, is consistent with the crystal structures derived for known Nim proteins, and specific amino acid residues important for substrate binding in the active site are conserved. This study demonstrates that the “universal” nim primers will not detect all nim genes with the ability to confer metronidazole resistance, but nimJ alone cannot account for the very high metronidazole MICs of these resistant clinical isolates. PMID:23716049

47 CFR 27.1239 - Reimbursement obligation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Reimbursement obligation. 27.1239 Section 27... Policies Governing the Transition of the 2500-2690 Mhz Band for Brs and Ebs § 27.1239 Reimbursement obligation. (a) A proponent may request reimbursement from BRS licensees and lessees, EBS lessees, and...

The role of gut microbiota in health and disease: In vitro modeling of host-microbe interactions at the aerobe-anaerobe interphase of the human gut.

PubMed

von Martels, Julius Z H; Sadaghian Sadabad, Mehdi; Bourgonje, Arno R; Blokzijl, Tjasso; Dijkstra, Gerard; Faber, Klaas Nico; Harmsen, Hermie J M

2017-04-01

The microbiota of the gut has many crucial functions in human health. Dysbiosis of the microbiota has been correlated to a large and still increasing number of diseases. Recent studies have mostly focused on analyzing the associations between disease and an aberrant microbiota composition. Functional studies using (in vitro) gut models are required to investigate the precise interactions that occur between specific bacteria (or bacterial mixtures) and gut epithelial cells. As most gut bacteria are obligate or facultative anaerobes, studying their effect on oxygen-requiring human gut epithelial cells is technically challenging. Still, several (anaerobic) bacterial-epithelial co-culture systems have recently been developed that mimic host-microbe interactions occurring in the human gut, including 1) the Transwell "apical anaerobic model of the intestinal epithelial barrier", 2) the Host-Microbiota Interaction (HMI) module, 3) the "Human oxygen-Bacteria anaerobic" (HoxBan) system, 4) the human gut-on-a-chip and 5) the HuMiX model. This review discusses the role of gut microbiota in health and disease and gives an overview of the characteristics and applications of these novel host-microbe co-culture systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecular analysis of the anaerobic rumen fungus Orpinomyces - insights into an AT-rich genome.

PubMed

Nicholson, Matthew J; Theodorou, Michael K; Brookman, Jayne L

2005-01-01

The anaerobic gut fungi occupy a unique niche in the intestinal tract of large herbivorous animals and are thought to act as primary colonizers of plant material during digestion. They are the only known obligately anaerobic fungi but molecular analysis of this group has been hampered by difficulties in their culture and manipulation, and by their extremely high A+T nucleotide content. This study begins to answer some of the fundamental questions about the structure and organization of the anaerobic gut fungal genome. Directed plasmid libraries using genomic DNA digested with highly or moderately rich AT-specific restriction enzymes (VspI and EcoRI) were prepared from a polycentric Orpinomyces isolate. Clones were sequenced from these libraries and the breadth of genomic inserts, both genic and intergenic, was characterized. Genes encoding numerous functions not previously characterized for these fungi were identified, including cytoskeletal, secretory pathway and transporter genes. A peptidase gene with no introns and having sequence similarity to a gene encoding a bacterial peptidase was also identified, extending the range of metabolic enzymes resulting from apparent trans-kingdom transfer from bacteria to fungi, as previously characterized largely for genes encoding plant-degrading enzymes. This paper presents the first thorough analysis of the genic, intergenic and rDNA regions of a variety of genomic segments from an anaerobic gut fungus and provides observations on rules governing intron boundaries, the codon biases observed with different types of genes, and the sequence of only the second anaerobic gut fungal promoter reported. Large numbers of retrotransposon sequences of different types were found and the authors speculate on the possible consequences of any such transposon activity in the genome. The coding sequences identified included several orphan gene sequences, including one with regions strongly suggestive of structural proteins such as collagens

26 CFR 2.1-20 - Obligation of deposits.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Obligation of deposits. 2.1-20 Section 2.1-20...) MARITIME CONSTRUCTION RESERVE FUND § 2.1-20 Obligation of deposits. (a) Time for obligation. Within three years from the date of any deposit in a construction reserve fund, unless extension is granted as...

Interaction of metronidazole with resistant and susceptible Bacteroides fragilis.

PubMed Central

McLafferty, M A; Koch, R L; Goldman, P

1982-01-01

The kinetics of the lethal action of metronidazole and the formation of acetamide have been studied in a strain of Bacteroides fragilis which is relatively resistant to metronidazole. As with a susceptible strain of B. fragilis, the data are consistent with a model in which a labile intermediate in metronidazole metabolism interacts either with water to form acetamide or with a bacterium to cause its death. Although the relatively resistant strain grows more slowly than the susceptible one and is killed less rapidly by metronidazole, the resistant strain displays the same relationship between the lethal action of metronidazole and metronidazole metabolism to acetamide. The relatively resistant strain, like the susceptible one, has an enhanced lethal response to metronidazole in the presence of a strain of Escherichia coli. The results suggest that the proposed labile reactive intermediate of metronidazole forms more slowly in the resistant strains. PMID:7081970

Standard of care, institutional obligations, and distributive justice.

PubMed

MacKay, Douglas

2015-05-01

The problem of standard of care in clinical research concerns the level of treatment that investigators must provide to subjects in clinical trials. Commentators often formulate answers to this problem by appealing to two distinct types of obligations: professional obligations and natural duties. In this article, I investigate whether investigators also possess institutional obligations that are directly relevant to the problem of standard of care, that is, those obligations a person has because she occupies a particular institutional role. I examine two types of institutional contexts: (1) public research agencies - agencies or departments of states that fund or conduct clinical research in the public interest; and (2) private-for-profit corporations. I argue that investigators who are employed or have their research sponsored by the former have a distinctive institutional obligation to conduct their research in a way that is consistent with the state's duty of distributive justice to provide its citizens with access to basic health care, and its duty to aid citizens of lower income countries. By contrast, I argue that investigators who are employed or have their research sponsored by private-for-profit corporations do not possess this obligation nor any other institutional obligation that is directly relevant to the ethics of RCTs. My account of the institutional obligations of investigators aims to contribute to the development of a reasonable, distributive justice-based account of standard of care. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Anaerobic Digestion and its Applications

EPA Science Inventory

Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

Anaerobic Biodegradation of Detergent Surfactants

PubMed Central

Merrettig-Bruns, Ute; Jelen, Erich

2009-01-01

Detergent surfactants can be found in wastewater in relevant concentrations. Most of them are known as ready degradable under aerobic conditions, as required by European legislation. Far fewer surfactants have been tested so far for biodegradability under anaerobic conditions. The natural environment is predominantly aerobic, but there are some environmental compartments such as river sediments, sub-surface soil layer and anaerobic sludge digesters of wastewater treatment plants which have strictly anaerobic conditions. This review gives an overview on anaerobic biodegradation processes, the methods for testing anaerobic biodegradability, and the anaerobic biodegradability of different detergent surfactant types (anionic, nonionic, cationic, amphoteric surfactants).

5 CFR 2635.809 - Just financial obligations.

Code of Federal Regulations, 2012 CFR

2012-01-01

... obligations. Employees shall satisfy in good faith their obligations as citizens, including all just financial... employee or reduced to judgment by a court. In good faith means an honest intention to fulfill any just...

5 CFR 2635.809 - Just financial obligations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... obligations. Employees shall satisfy in good faith their obligations as citizens, including all just financial... employee or reduced to judgment by a court. In good faith means an honest intention to fulfill any just...

5 CFR 2635.809 - Just financial obligations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... obligations. Employees shall satisfy in good faith their obligations as citizens, including all just financial... employee or reduced to judgment by a court. In good faith means an honest intention to fulfill any just...

Social categories as markers of intrinsic interpersonal obligations.

PubMed

Rhodes, Marjorie; Chalik, Lisa

2013-06-01

Social categorization is an early-developing feature of human social cognition, yet the role that social categories play in children's understanding of and predictions about human behavior has been unclear. In the studies reported here, we tested whether a foundational functional role of social categories is to mark people as intrinsically obligated to one another (e.g., obligated to protect rather than harm). In three studies, children (aged 3-9, N = 124) viewed only within-category harm as violating intrinsic obligations; in contrast, they viewed between-category harm as violating extrinsic obligations defined by explicit rules. These data indicate that children view social categories as marking patterns of intrinsic interpersonal obligations, suggesting that a key function of social categories is to support inferences about how people will relate to members of their own and other groups.

Filial Obligation and Marital Satisfaction in Middle-aged Couples

PubMed Central

Seidel, Amber J.; Birditt, Kira S.; Zarit, Steven H.; Fingerman, Karen L.

2017-01-01

Abstract Purpose of the Study: Although prior research suggests that high filial obligation has an adverse impact on psychological well-being, little is known about the implications of these beliefs for marital quality during midlife. Therefore, the purpose of this study was to examine dyadic associations between middle-aged husbands’ and wives’ filial obligation beliefs and their marital satisfaction. Design and Methods: Using a sample of 132 middle-aged husbands (M = 51.45 years) and wives (M = 49.75 years) drawn from Wave 1 of the Family Exchanges Study, we tested actor–partner interdependence models to determine associations between husbands’ and wives’ filial obligation beliefs and marital satisfaction in both spouses. We also examined associations between spousal dissimilarity in filial obligation and marital satisfaction. Results: Wives’ greater filial obligation was associated with their own lower marital satisfaction. Conversely, husbands’ greater filial obligation was associated with their own higher marital satisfaction. Greater spousal dissimilarity in filial obligation was associated with lower levels of marital satisfaction for husbands but not for wives. Implications: Given that support provided to aging parents most often occurs within the context of marriage, findings highlight the importance of examining dyadic associations between filial obligation beliefs and marital quality among middle-aged couples. PMID:26613745

Is there a moral obligation not to infect others?

PubMed

Harris, J; Holm, S

1995-11-04

The emergence of HIV infection and AIDS has refocused concern on the obligations surrounding the carrying and transmission of communicable diseases. This article asks three related questions: Is there a general duty not to spread contagion? Are there special obligations not to communicate disease in the workplace? And does the mode of transmission of the disease affect the ethics of transmission and, if so, how and to what extent? There seems to be a strong prima facie obligation not to harm others by making them ill where this is avoidable, and this obligation not to communicate disease applies as much to relatively trivial diseases like the common cold as it does to HIV disease. The reasonableness of expecting people to live up to this obligation, however, depends on society reciprocating the obligation in the form of providing protection and compensation.

Haloanaerobium kushneri sp. nov., an obligately halophilic, anaerobic bacterium from an oil brine

NASA Technical Reports Server (NTRS)

Bhupathiraju, V. K.; McInerney, M. J.; Woese, C. R.; Tanner, R. S.

1999-01-01

Three strains, designated VS-751T, VS-511 and VS-732, of a strictly anaerobic, moderately halophilic, Gram-negative, rod-shaped bacterium were isolated from a highly saline (15-20%) brine from an oil reservoir in central Oklahoma, USA. The optimal concentration of NaCl for growth of these three strains was 2 M (12%), and the strains also grew in the presence of an additional 1 M MgCl2. The strains were mesophilic and grew at a pH range of 6-8. Carbohydrates used by all three strains included glucose, fructose, arabinose, galactose, maltose, mannose, cellobiose, sucrose and inulin. Glucose fermentation products included ethanol, acetate, H2 and CO2, with formate produced by two of the three strains. Differences were noted among strains in the optimal temperature and pH for growth, the maximum and minimum NaCl concentration that supported growth, substrate utilization and cellular fatty acid composition. Despite the phenotypic differences among the three strains, analysis of the 16S rRNA gene sequences and DNA-DNA hybridizations showed that these three strains were members of the same genospecies which belonged to the genus Haloanaerobium. The phenotypic and genotypic characteristics of strains VS-751T, VS-511 and VS-732 are different from those of previously described species of Haloanaerobium. It is proposed that strain VS-751T (ATCC 700103T) be established as the type strain of a new species, Haloanaerobium kushneri.

[Current clinical significance of anaerobic bacteremia].

PubMed

Jirsa, Roman; Marešová, Veronika; Brož, Zdeněk

2010-10-01

to estimate tje current clinical significance of anaerobic bacteremia in a group of Czech hospitals. this retrospective analysis comprised 8 444 anaerobic blood cultures in patients admitted to four Czech hospitals between 2004 and 2007. in 16 patients, blood cultures yielded significant anaerobic bacteria. Thus, anaerobic bacteremia accounted for less than 2 % of clinically significant bacteremia. Four patients (18 %) died but none of the deaths could be clearly attributable to anaerobic bacteria in the bloodstream. The most common comorbidities predisposing to anaerobic bacteremia and the most frequent sources of infection were similar to those reported by other authors. The majority of anaerobic bacteremia cases were due to gram-negative bacteria, followed by Clostridium perfringens and, surprisingly, Eubacterium spp. (particularly Eubacterium lentum). anaerobic bacteremia remains rare. The comparison of our data with those by other authors suggests that (despite the reported high mortality) the actual clinical significance of anaerobic bacteremia is rather controversial and that the anaerobic bacteremia might not correspond to more serious pathogenic role of the anaerobic bacteria as the source of infection.

Population dynamics of obligate cooperators

PubMed Central

Courchamp, F.; Grenfell, B.; Clutton-Brock, T.

1999-01-01

Obligate cooperative breeding species demonstrate a high rate of group extinction, which may be due to the existence of a critical number of helpers below which the group cannot subsist. Through a simple model, we study the population dynamics of obligate cooperative breeding species, taking into account the existence of a lower threshold below which the instantaneous growth rate becomes negative. The model successively incorporates (i) a distinction between species that need helpers for reproduction, survival or both, (ii) the existence of a migration rate accounting for dispersal, and (iii) stochastic mortality to simulate the effects of random catastrophic events. Our results suggest that the need for a minimum number of helpers increases the risk of extinction for obligate cooperative breeding species. The constraint imposed by this threshold is higher when helpers are needed for reproduction only or for both reproduction and survival. By driving them below this lower threshold, stochastic mortality of lower amplitude and/or lower frequency than for non-cooperative breeders may be sufficient to cause the extinction of obligate cooperative breeding groups. Migration may have a buffering effect only for groups where immigration is higher than emigration; otherwise (when immigrants from nearby groups are not available) it lowers the difference between actual group size and critical threshold, thereby constituting a higher constraint.

Whistleblowing and the bioethicist's public obligations.

PubMed

MacDougall, D Robert

2014-10-01

Bioethicists are sometimes thought to have heightened obligations by virtue of the fact that their professional role addresses ethics or morals. For this reason it has been argued that bioethicists ought to "whistleblow"--that is, publicly expose the wrongful or potentially harmful activities of their employer--more often than do other kinds of employees. This article argues that bioethicists do indeed have a heightened obligation to whistleblow, but not because bioethicists have heightened moral obligations in general. Rather, the special duties of bioethicists to act as whistleblowers are best understood by examining the nature of the ethical dilemma typically encountered by private employees and showing why bioethicists do not encounter this dilemma in the same way. Whistleblowing is usually understood as a moral dilemma involving conflicting duties to two parties: the public and a private employer. However, this article argues that this way of understanding whistleblowing has the implication that professions whose members identify their employer as the public-such as government employees or public servants--cannot consider whistleblowing a moral dilemma, because obligations are ultimately owed to only one party: the public. The article contends that bioethicists--even when privately employed--are similar to government employees in the sense that they do not have obligations to defer to the judgments of those with private interests. Consequently, bioethicists may be considered to have a special duty to whistleblow, although for different reasons than those usually cited.

[Pyothorax in 26 cats: clinical signs, laboratory results and therapy (2000-2007)].

PubMed

Ottenjann, Mareike; Lübke-Becker, Antina; Linzmann, Helge; Brunnberg, Leo; Kohn, Barbara

2008-01-01

Common historical findings in 26 cats with pyothorax were dyspnea (85%), lethargy (65%), and anorexia (62%), common clinical findings were dyspnea (89%), tachypnea (73%), fever (39%), and hypothermia (27%). Frequent laboratory abnormalities were leukocytosis (68%) with a left shift (100%), anemia (65%), hypoalbuminemia (91%), hyperglobulinemia (86%), hyperbilirubinemia (60%) as well as azotemia (52%). The thoracic effusion was purulent in all cats, the thoracic fluid evaluation (n = 19) met the criteria for an inflammatory exudate (protein 32-63 g/l, median 44; cell count 54.4-390 x 10(9)/l, median 100). Cytological analysis revealed bacteria in 21 of 24 cats. From 16 cats 13 different genera were isolated, 5 cultures were without bacterial growth. In 12.5% of the cats a single population of bacteria was identified, and in 87.5% a mixture of 2-4 different bacterial species were cultured. Obligate anaerobic bacteria were the most common isolates (70%) followed by facultative anaerob (22.5%) and aerob growing (7.5%) bacteria. Bacterial culture most often yielded Fusobacteria spp., Prevotella spp., Pasteurella spp., Porphyromonas spp. and Bacteroides spp. Three cats were euthanized at the day of presentation. A thoracic lavage was performed in 22 cats; mechanical complications with the chest tubes occured in 4 cats. Thoracotomy was performed in 2 cats. Of the 23 treated cats 17 survived (74%).

Patients' ethical obligation for their health.

PubMed Central

Sider, R C; Clements, C D

1984-01-01

In contemporary medical ethics health is rarely acknowledged to be an ethical obligation. This oversight is due to the preoccupation of most bioethicists with a rationalist, contract model for ethics in which moral obligation is limited to truth-telling and promise-keeping. Such an ethics is poorly suited to medicine because it fails to appreciate that medicine's basis as a moral enterprise is oriented towards health values. A naturalistic model for medical ethics is proposed which builds upon biological and medical values. This perspective clarifies ethical obligations to ourselves and to others for life and health. It provides a normative framework for the doctor-patient relationship within which to formulate medical advice and by which to evaluate patient choice. PMID:6502640

24 CFR 266.415 - Mortgage lien and other obligations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... determine, that all contractual obligations in connection with the mortgage transaction, including the... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Mortgage lien and other obligations... Mortgage and Closing Requirements; HUD Endorsement § 266.415 Mortgage lien and other obligations. (a) Liens...

Is there a moral obligation not to infect others?

PubMed Central

Harris, J.; Holm, S.

1995-01-01

The emergence of HIV infection and AIDS has refocused concern on the obligations surrounding the carrying and transmission of communicable diseases. This article asks three related questions: Is there a general duty not to spread contagion? Are there special obligations not to communicate disease in the workplace? And does the mode of transmission of the disease affect the ethics of transmission and, if so, how and to what extent? There seems to be a strong prima facie obligation not to harm others by making them ill where this is avoidable, and this obligation not to communicate disease applies as much to relatively trivial diseases like the common cold as it does to HIV disease. The reasonableness of expecting people to live up to this obligation, however, depends on society reciprocating the obligation in the form of providing protection and compensation. Images p1216-a p1216-b p1217-a PMID:7488907

A portable anaerobic microbioreactor reveals optimum growth conditions for the methanogen Methanosaeta concilii.

PubMed

Steinhaus, Benjamin; Garcia, Marcelo L; Shen, Amy Q; Angenent, Largus T

2007-03-01

Conventional studies of the optimum growth conditions for methanogens (methane-producing, obligate anaerobic archaea) are typically conducted with serum bottles or bioreactors. The use of microfluidics to culture methanogens allows direct microscopic observations of the time-integrated response of growth. Here, we developed a microbioreactor (microBR) with approximately 1-microl microchannels to study some optimum growth conditions for the methanogen Methanosaeta concilii. The microBR is contained in an anaerobic chamber specifically designed to place it directly onto an inverted light microscope stage while maintaining a N2-CO2 environment. The methanogen was cultured for months inside microchannels of different widths. Channel width was manipulated to create various fluid velocities, allowing the direct study of the behavior and responses of M. concilii to various shear stresses and revealing an optimum shear level of approximately 20 to 35 microPa. Gradients in a single microchannel were then used to find an optimum pH level of 7.6 and an optimum total NH4-N concentration of less than 1,100 mg/liter (<47 mg/liter as free NH3-N) for M. concilii under conditions of the previously determined ideal shear stress and pH and at a temperature of 35 degrees C.

Medicago truncatula DNF2 is a PI-PLC-XD-containing protein required for bacteroid persistence and prevention of nodule early senescence and defense-like reactions.

PubMed

Bourcy, Marie; Brocard, Lysiane; Pislariu, Catalina I; Cosson, Viviane; Mergaert, Peter; Tadege, Millon; Mysore, Kirankumar S; Udvardi, Michael K; Gourion, Benjamin; Ratet, Pascal

2013-03-01

Medicago truncatula and Sinorhizobium meliloti form a symbiotic association resulting in the formation of nitrogen-fixing nodules. Nodule cells contain large numbers of bacteroids which are differentiated, nitrogen-fixing forms of the symbiotic bacteria. In the nodules, symbiotic plant cells home and maintain hundreds of viable bacteria. In order to better understand the molecular mechanism sustaining the phenomenon, we searched for new plant genes required for effective symbiosis. We used a combination of forward and reverse genetics approaches to identify a gene required for nitrogen fixation, and we used cell and molecular biology to characterize the mutant phenotype and to gain an insight into gene function. The symbiotic gene DNF2 encodes a putative phosphatidylinositol phospholipase C-like protein. Nodules formed by the mutant contain a zone of infected cells reduced to a few cell layers. In this zone, bacteria do not differentiate properly into bacteroids. Furthermore, mutant nodules senesce rapidly and exhibit defense-like reactions. This atypical phenotype amongst Fix(-) mutants unravels dnf2 as a new actor of bacteroid persistence inside symbiotic plant cells. © 2012 CNRS. New Phytologist © 2012 New Phytologist Trust.

Products of dark CO sub 2 fixation in pea root nodules support bacteroid metabolism. [Pisum sativum L

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosendahl, L.; Pedersen, W.B.; Vance, C.P.

1990-05-01

Products of the nodule cytosol in vivo dark ({sup 14}C)CO{sub 2} fixation were detected in the plant cytosol as well as in the bacteroids of pea (Pisum sativum L. cv Bodil) nodules. The distribution of the metabolites of the dark CO{sub 2} fixation products was compared in effective (fix{sup +}) nodules infected by a wild-type Rhizobium leguminosarum (MNF 300), and ineffective (fix{sup {minus}}) nodules of the R. leguminosarum mutant MNF 3080. The latter has a defect in the dicarboxylic acid transport system of the bacterial membrane. The {sup 14}C incorporation from ({sup 14}C)CO{sub 2} was about threefold greater in themore » wild-type nodules than in the mutant nodules. Similarly, in wild-type nodules the in vitro phosphoenolpyruvate carboxylase activity was substantially greater than that of the mutant. Almost 90% of the {sup 14}C label in the cytosol was found in organic acids in both symbioses. The results indicate a central role for nodule cytosol dark CO{sub 2} fixation in the supply of the bacteroids with dicarboxylic acids.« less

Inability and Obligation in Moral Judgment

PubMed Central

Buckwalter, Wesley; Turri, John

2015-01-01

It is often thought that judgments about what we ought to do are limited by judgments about what we can do, or that “ought implies can.” We conducted eight experiments to test the link between a range of moral requirements and abilities in ordinary moral evaluations. Moral obligations were repeatedly attributed in tandem with inability, regardless of the type (Experiments 1–3), temporal duration (Experiment 5), or scope (Experiment 6) of inability. This pattern was consistently observed using a variety of moral vocabulary to probe moral judgments and was insensitive to different levels of seriousness for the consequences of inaction (Experiment 4). Judgments about moral obligation were no different for individuals who can or cannot perform physical actions, and these judgments differed from evaluations of a non-moral obligation (Experiment 7). Together these results demonstrate that commonsense morality rejects the “ought implies can” principle for moral requirements, and that judgments about moral obligation are made independently of considerations about ability. By contrast, judgments of blame were highly sensitive to considerations about ability (Experiment 8), which suggests that commonsense morality might accept a “blame implies can” principle. PMID:26296206

47 CFR 211.7 - Obligation of carriers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Obligation of carriers. 211.7 Section 211.7 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EMERGENCY RESTORATION PRIORITY PROCEDURES FOR TELECOMMUNICATIONS SERVICES § 211.7 Obligation of carriers. (a) During the...

47 CFR 211.7 - Obligation of carriers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Obligation of carriers. 211.7 Section 211.7 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EMERGENCY RESTORATION PRIORITY PROCEDURES FOR TELECOMMUNICATIONS SERVICES § 211.7 Obligation of carriers. (a) During the...

47 CFR 211.7 - Obligation of carriers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Obligation of carriers. 211.7 Section 211.7 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EMERGENCY RESTORATION PRIORITY PROCEDURES FOR TELECOMMUNICATIONS SERVICES § 211.7 Obligation of carriers. (a) During the...

47 CFR 211.7 - Obligation of carriers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Obligation of carriers. 211.7 Section 211.7 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EMERGENCY RESTORATION PRIORITY PROCEDURES FOR TELECOMMUNICATIONS SERVICES § 211.7 Obligation of carriers. (a) During the...

47 CFR 211.7 - Obligation of carriers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Obligation of carriers. 211.7 Section 211.7 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EMERGENCY RESTORATION PRIORITY PROCEDURES FOR TELECOMMUNICATIONS SERVICES § 211.7 Obligation of carriers. (a) During the...

Distribution, Detection of Enterotoxigenic Strains and Antimicrobial Drug Susceptibility Patterns of Bacteroides Fragilis Group in Diarrheic and Non-Diarrheic Feces from Brazilian Infants

PubMed Central

Ferreira, Débora Paula; Silva, Vânia Lúcia; Guimarães, Danielle Aparecida; Coelho, Cíntia Marques; Zauli, Danielle Alves Gomes; Farias, Luiz Macêdo; Carvalho, Maria Auxiliadora Roque; Diniz, Claudio Galuppo

2010-01-01

Despite the importance of gastrointestinal diseases and their global distribution, affecting millions of individuals around the world, the role and antimicrobial susceptibility patterns of anaerobic bacteria such as those in the Bacteroides fragilis group (BFG) are still unclear in young children. This study investigated the occurrence and distribution of species in the BFG and enterotoxigenic strains in the fecal microbiota of children and their antimicrobial susceptibility patterns. Diarrheic (n=110) and non-diarrheic (n=65) fecal samples from children aged 0–5 years old were evaluated. BFG strains were isolated and identified by conventional biochemical, physiological and molecular approaches. Alternatively, bacteria and enterotoxigenic strains were detected directly from feces by molecular biology. Antimicrobial drug susceptibility patterns were determined by the agar dilution method according to the guidelines for isolated bacteria. BFG was detected in 64.3% of the fecal samples (55% diarrheic and 80.4% non-diarrheic), and 4.6% were enterotoxigenic. Antimicrobial resistance was observed against ampicillin, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol. The data show that these bacteria are prevalent in fecal microbiota at higher levels in healthy children. The molecular methodology was more effective in identifying the B. fragilis group when compared to the biochemical and physiological techniques. The observation of high resistance levels stimulates thoughts about the indiscriminate use of antimicrobial drugs in early infancy. Further quantitative studies are needed to gain a better understanding of the role of these bacteria in acute diarrhea in children. PMID:24031535

49 CFR 22.17 - Compliance with child support obligations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 1 2014-10-01 2014-10-01 false Compliance with child support obligations. 22.17...) Policies Applying to STLP Loans § 22.17 Compliance with child support obligations. Any holder of 50% or... than 60 days delinquent on any obligation to pay child support arising under: (a) An administrative...

49 CFR 22.17 - Compliance with child support obligations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 1 2013-10-01 2013-10-01 false Compliance with child support obligations. 22.17...) Policies Applying to STLP Loans § 22.17 Compliance with child support obligations. Any holder of 50% or... than 60 days delinquent on any obligation to pay child support arising under: (a) An administrative...

49 CFR 22.17 - Compliance with child support obligations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 1 2010-10-01 2010-10-01 false Compliance with child support obligations. 22.17...) Policies Applying to STLP Loans § 22.17 Compliance with child support obligations. Any holder of 50% or... than 60 days delinquent on any obligation to pay child support arising under: (a) An administrative...

49 CFR 22.17 - Compliance with child support obligations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 1 2012-10-01 2012-10-01 false Compliance with child support obligations. 22.17...) Policies Applying to STLP Loans § 22.17 Compliance with child support obligations. Any holder of 50% or... than 60 days delinquent on any obligation to pay child support arising under: (a) An administrative...

49 CFR 22.17 - Compliance with child support obligations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 1 2011-10-01 2011-10-01 false Compliance with child support obligations. 22.17...) Policies Applying to STLP Loans § 22.17 Compliance with child support obligations. Any holder of 50% or... than 60 days delinquent on any obligation to pay child support arising under: (a) An administrative...

Impact of human milk bacteria and oligosaccharides on neonatal gut microbiota establishment and gut health.

PubMed

Jost, Ted; Lacroix, Christophe; Braegger, Christian; Chassard, Christophe

2015-07-01

Neonatal gut microbiota establishment represents a crucial stage for gut maturation, metabolic and immunologic programming, and consequently short- and long-term health status. Human milk beneficially influences this process due to its dynamic profile of age-adapted nutrients and bioactive components and by providing commensal maternal bacteria to the neonatal gut. These include Lactobacillus spp., as well as obligate anaerobes such as Bifidobacterium spp., which may originate from the maternal gut via an enteromammary pathway as a novel form of mother-neonate communication. Additionally, human milk harbors a broad range of oligosaccharides that promote the growth and activity of specific bacterial populations, in particular, Bifidobacterium and Bacteroides spp. This review focuses on the diversity and origin of human milk bacteria, as well as on milk oligosaccharides that influence neonatal gut microbiota establishment. This knowledge can be used to develop infant formulae that more closely mimic nature's model and sustain a healthy gut microbiota. © The Author(s) 2015. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Wingate Anaerobic Test peak power and anaerobic capacity classifications for men and women intercollegiate athletes.

PubMed

Zupan, Michael F; Arata, Alan W; Dawson, Letitia H; Wile, Alfred L; Payn, Tamara L; Hannon, Megan E

2009-12-01

The Wingate Anaerobic Test (WAnT) has been established as an effective tool in measuring both muscular power and anaerobic capacity in a 30-second time period; however, there are no published normative tables by which to compare WAnT performance in men and women intercollegiate athletics. The purpose of this study was to develop a classification system for anaerobic peak power and anaerobic capacity for men and women National Collegiate Athletic Association (NCAA) Division I college athletes using the WAnT. A total of 1,585 (1,374 men and 211 women) tests were conducted on athletes ranging from the ages of 18 to 25 years using the WAnT. Absolute and relative peak power and anaerobic capacity data were recorded. One-half standard deviations were used to set up a 7-tier classification system (poor to elite) for these assessments. These classifications can be used by athletes, coaches, and practitioners to evaluate anaerobic peak power and anaerobic capacity in their athletes.

7 CFR 1000.28 - Termination of obligations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... which the market administrator receives the handler's report of receipts and utilization on which such obligation is based, unless within such 2-year period, the market administrator notifies the handler in... producer(s) or such cooperative association, or if the obligation is payable to the market administrator...

10 CFR 611.112 - Termination of obligations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Termination of obligations. 611.112 Section 611.112 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS ADVANCED TECHNOLOGY VEHICLES MANUFACTURER ASSISTANCE PROGRAM Direct Loan Program § 611.112 Termination of obligations. DOE, the Federal Financing Bank, and the...

5 CFR 2426.13 - Obligation to consult.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Obligation to consult. 2426.13 Section 2426.13 Administrative Personnel FEDERAL LABOR RELATIONS AUTHORITY, GENERAL COUNSEL OF THE FEDERAL... Regulations § 2426.13 Obligation to consult. (a) When a labor organization has been accorded consultation...

Bacterial Population Adherent to the Epithelium on the Roo of the Dorsal Rumen of Sheep †

PubMed Central

Dehority, Burk A.; Grubb, Jean A.

1981-01-01

By anaerobic procedures, the total number of adherent bacteria was determined on tissue samples obtained from the roof of the dorsal rumen of three sheep. After four washings, 1.91 × 107, 0.34 × 107, and 1.23 × 107 bacteria per cm2 were still attached to the rumen epithelium in sheep 1, 2, and 3, respectively. A total of 95 strains of bacteria were isolated from these three samples. Based on morphology, Gram stain, anaerobiosis, motility, and fermentation end products, they were presumptively identified as follows: Butyrivibrio fibrisolvens, 30 strains; atypical Butyrivibrio, 5 strains; Bacteroides ruminicola, 22 strains; Lactobacillus, 1 strain; and unknown Bacteroides species, 37 strains. For sheep 3, washing the rumen epithelium a total of 10 times reduced the adherent bacterial population by 93% (8.4 × 105 bacteria per cm2). Of 30 strains isolated from this sample, 22 were presumptively identified as Butyrivibrio and Bacteroides types. These results suggest that the epithelium on the roof of the dorsal rumen is primarily colonized by two genera of bacteria, Butyrivibrio and Bacteroides. Most Butyrivibrio and Bacteroides ruminicola strains appeared to be similar to previously isolated rumen strains. However, the unknown Bacteroides species differed considerably from the three species of this genus which are commonly isolated from rumen contents. PMID:16345797

Modulation of small intestinal homeostasis along with its microflora during acclimatization at simulated hypobaric hypoxia.

PubMed

Adak, Atanu; Ghosh; Mondal, Keshab Chandra

2014-11-01

At high altitude (HA) hypobaric hypoxic environment manifested several pathophysiological consequences of which gastrointestinal (GI) disorder are very common phenomena. To explore the most possible clue behind this disorder intestinal flora, the major player of the GI functions, were subjected following simulated hypobaric hypoxic treatment in model animal. For this, male albino rats were exposed to 55 kPa (approximately 4872.9 m) air pressure consecutively for 30 days for 8 h/day and its small intestinal microflora, their secreted digestive enzymes and stress induced marker protein were investigated of the luminal epithelia. It was observed that population density of total aerobes significantly decreased, but the quantity of total anaerobes and Escherichia coli increased significantly after 30 days of hypoxic stress. The population density of strict anaerobes like Bifidobacterium sp., Bacteroides sp. and Lactobacillus sp. and obligate anaerobes like Clostridium perfringens and Peptostreptococcus sp. were expanded along with their positive growth direction index (GDI). In relation to the huge multiplication of anaerobes the amount of gas formation as well as content of IgA and IgG increased in duration dependent manner. The activity of some luminal enzymes from microbial origin like a-amylase, gluco-amylase, proteinase, alkaline phosphatase and beta-glucuronidase were also elevated in hypoxic condition. Besides, hypoxia induced in formation of malondialdehyde along with significant attenuation of catalase, glutathione peroxidase, superoxide dismutase activity and lowered GSH/GSSG pool in the intestinal epithelia. Histological study revealed disruption of intestinal epithelial barrier with higher infiltration of lymphocytes in lamina propia and atrophic structure. It can be concluded that hypoxia at HA modified GI microbial imprint and subsequently causes epithelial barrier dysfunction which may relate to the small intestinal dysfunction at HA.

18 CFR 346.3 - Asset retirement obligations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Asset retirement obligations. 346.3 Section 346.3 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... to the asset retirement obligations that are included in the book balances of all accounts reflected...

18 CFR 35.18 - Asset retirement obligations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Asset retirement obligations. 35.18 Section 35.18 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Other Filing Requirements § 35.18 Asset retirement obligations. (a) A public utility that files a rate...

18 CFR 35.18 - Asset retirement obligations.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Asset retirement obligations. 35.18 Section 35.18 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Other Filing Requirements § 35.18 Asset retirement obligations. (a) A public utility that files a rate...

18 CFR 35.18 - Asset retirement obligations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Asset retirement obligations. 35.18 Section 35.18 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Other Filing Requirements § 35.18 Asset retirement obligations. (a) A public utility that files a rate...

18 CFR 35.18 - Asset retirement obligations.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Asset retirement obligations. 35.18 Section 35.18 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Other Filing Requirements § 35.18 Asset retirement obligations. (a) A public utility that files a rate...

18 CFR 35.18 - Asset retirement obligations.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Asset retirement obligations. 35.18 Section 35.18 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Other Filing Requirements § 35.18 Asset retirement obligations. (a) A public utility that files a rate...

26 CFR 1.454-1 - Obligations issued at discount.

Code of Federal Regulations, 2010 CFR

2010-04-01

... series E bond, at which time the stated redemption value was $674.60. A never elected under section 454(a... obligation, in which he retains his investment in a matured series E U.S. savings bond, or (iii) A nontransferable obligation (whether or not a current income obligation) of the United States for which a series E...

18 CFR 154.315 - Asset retirement obligations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Asset retirement obligations. 154.315 Section 154.315 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Filed With Changes § 154.315 Asset retirement obligations. (a) A natural gas company that files a tariff...

18 CFR 154.315 - Asset retirement obligations.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Asset retirement obligations. 154.315 Section 154.315 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Filed With Changes § 154.315 Asset retirement obligations. (a) A natural gas company that files a tariff...

18 CFR 154.315 - Asset retirement obligations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Asset retirement obligations. 154.315 Section 154.315 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Filed With Changes § 154.315 Asset retirement obligations. (a) A natural gas company that files a tariff...

18 CFR 154.315 - Asset retirement obligations.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Asset retirement obligations. 154.315 Section 154.315 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Filed With Changes § 154.315 Asset retirement obligations. (a) A natural gas company that files a tariff...

18 CFR 154.315 - Asset retirement obligations.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Asset retirement obligations. 154.315 Section 154.315 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Filed With Changes § 154.315 Asset retirement obligations. (a) A natural gas company that files a tariff...

22 CFR 221.15 - Fiscal Agent obligations.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Fiscal Agent obligations. 221.15 Section 221.15 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS AND CONDITIONS The Guarantee § 221.15 Fiscal Agent obligations. Failure of the Fiscal Agent to perform any of its...

22 CFR 221.15 - Fiscal Agent obligations.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Fiscal Agent obligations. 221.15 Section 221.15 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS AND CONDITIONS The Guarantee § 221.15 Fiscal Agent obligations. Failure of the Fiscal Agent to perform any of its...

22 CFR 221.15 - Fiscal Agent obligations.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Fiscal Agent obligations. 221.15 Section 221.15 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS AND CONDITIONS The Guarantee § 221.15 Fiscal Agent obligations. Failure of the Fiscal Agent to perform any of its...

22 CFR 221.15 - Fiscal Agent obligations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Fiscal Agent obligations. 221.15 Section 221.15 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS AND CONDITIONS The Guarantee § 221.15 Fiscal Agent obligations. Failure of the Fiscal Agent to perform any of its...

22 CFR 221.15 - Fiscal Agent obligations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Fiscal Agent obligations. 221.15 Section 221.15 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS AND CONDITIONS The Guarantee § 221.15 Fiscal Agent obligations. Failure of the Fiscal Agent to perform any of its...

26 CFR 1.103-16 - Obligations of certain volunteer fire departments.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 2 2012-04-01 2012-04-01 false Obligations of certain volunteer fire....103-16 Obligations of certain volunteer fire departments. (a) General rule. An obligation of a volunteer fire department issued after December 31, 1980, shall be treated as an obligation of a political...

26 CFR 1.103-16 - Obligations of certain volunteer fire departments.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 26 Internal Revenue 2 2013-04-01 2013-04-01 false Obligations of certain volunteer fire....103-16 Obligations of certain volunteer fire departments. (a) General rule. An obligation of a volunteer fire department issued after December 31, 1980, shall be treated as an obligation of a political...

26 CFR 1.103-16 - Obligations of certain volunteer fire departments.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 2 2011-04-01 2011-04-01 false Obligations of certain volunteer fire....103-16 Obligations of certain volunteer fire departments. (a) General rule. An obligation of a volunteer fire department issued after December 31, 1980, shall be treated as an obligation of a political...

26 CFR 1.103-16 - Obligations of certain volunteer fire departments.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Obligations of certain volunteer fire....103-16 Obligations of certain volunteer fire departments. (a) General rule. An obligation of a volunteer fire department issued after December 31, 1980, shall be treated as an obligation of a political...

26 CFR 1.103-16 - Obligations of certain volunteer fire departments.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 26 Internal Revenue 2 2014-04-01 2014-04-01 false Obligations of certain volunteer fire....103-16 Obligations of certain volunteer fire departments. (a) General rule. An obligation of a volunteer fire department issued after December 31, 1980, shall be treated as an obligation of a political...

Cultivation of Anaerobic and Facultatively Anaerobic Bacteria from Spacecraft-Associated Clean Rooms▿

PubMed Central

Stieglmeier, Michaela; Wirth, Reinhard; Kminek, Gerhard; Moissl-Eichinger, Christine

2009-01-01

In the course of this biodiversity study, the cultivable microbial community of European spacecraft-associated clean rooms and the Herschel Space Observatory located therein were analyzed during routine assembly operations. Here, we focused on microorganisms capable of growing without oxygen. Anaerobes play a significant role in planetary protection considerations since extraterrestrial environments like Mars probably do not provide enough oxygen for fully aerobic microbial growth. A broad assortment of anaerobic media was used in our cultivation strategies, which focused on microorganisms with special metabolic skills. The majority of the isolated strains grew on anaerobic, complex, nutrient-rich media. Autotrophic microorganisms or microbes capable of fixing nitrogen were also cultivated. A broad range of facultatively anaerobic bacteria was detected during this study and also, for the first time, some strictly anaerobic bacteria (Clostridium and Propionibacterium) were isolated from spacecraft-associated clean rooms. The multiassay cultivation approach was the basis for the detection of several bacteria that had not been cultivated from these special environments before and also led to the discovery of two novel microbial species of Pseudomonas and Paenibacillus. PMID:19363082

Cultivation of anaerobic and facultatively anaerobic bacteria from spacecraft-associated clean rooms.

PubMed

Stieglmeier, Michaela; Wirth, Reinhard; Kminek, Gerhard; Moissl-Eichinger, Christine

2009-06-01

In the course of this biodiversity study, the cultivable microbial community of European spacecraft-associated clean rooms and the Herschel Space Observatory located therein were analyzed during routine assembly operations. Here, we focused on microorganisms capable of growing without oxygen. Anaerobes play a significant role in planetary protection considerations since extraterrestrial environments like Mars probably do not provide enough oxygen for fully aerobic microbial growth. A broad assortment of anaerobic media was used in our cultivation strategies, which focused on microorganisms with special metabolic skills. The majority of the isolated strains grew on anaerobic, complex, nutrient-rich media. Autotrophic microorganisms or microbes capable of fixing nitrogen were also cultivated. A broad range of facultatively anaerobic bacteria was detected during this study and also, for the first time, some strictly anaerobic bacteria (Clostridium and Propionibacterium) were isolated from spacecraft-associated clean rooms. The multiassay cultivation approach was the basis for the detection of several bacteria that had not been cultivated from these special environments before and also led to the discovery of two novel microbial species of Pseudomonas and Paenibacillus.

18 CFR 1314.6 - Obligations of TVA.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Obligations of TVA. 1314.6 Section 1314.6 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY BOOK-ENTRY PROCEDURES FOR TVA POWER SECURITIES ISSUED THROUGH THE FEDERAL RESERVE BANKS § 1314.6 Obligations of TVA. (a...

12 CFR 1.100 - Indirect general obligations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... powers of taxation. Pursuant to § 1.2(b), an obligation issued by an obligor not possessing general powers of taxation qualifies as a general obligation of a State or political subdivision for the purposes of 12 U.S.C. 24 (Seventh), if a party possessing general powers of taxation unconditionally promises...

Vitamin and Amino Acid Auxotrophy in Anaerobic Consortia Operating under Methanogenic Conditions

PubMed Central

Hubalek, Valerie; Buck, Moritz; Tan, BoonFei; Foght, Julia; Wendeberg, Annelie; Berry, David; Bertilsson, Stefan

2017-01-01

ABSTRACT Syntrophy among Archaea and Bacteria facilitates the anaerobic degradation of organic compounds to CH4 and CO2. Particularly during aliphatic and aromatic hydrocarbon mineralization, as in the case of crude oil reservoirs and petroleum-contaminated sediments, metabolic interactions between obligate mutualistic microbial partners are of central importance. Using micromanipulation combined with shotgun metagenomic approaches, we describe the genomes of complex consortia within short-chain alkane-degrading cultures operating under methanogenic conditions. Metabolic reconstruction revealed that only a small fraction of genes in the metagenome-assembled genomes encode the capacity for fermentation of alkanes facilitated by energy conservation linked to H2 metabolism. Instead, the presence of inferred lifestyles based on scavenging anabolic products and intermediate fermentation products derived from detrital biomass was a common feature. Additionally, inferred auxotrophy for vitamins and amino acids suggests that the hydrocarbon-degrading microbial assemblages are structured and maintained by multiple interactions beyond the canonical H2-producing and syntrophic alkane degrader-methanogen partnership. Compared to previous work, our report points to a higher order of complexity in microbial consortia engaged in anaerobic hydrocarbon transformation. IMPORTANCE Microbial interactions between Archaea and Bacteria mediate many important chemical transformations in the biosphere from degrading abundant polymers to synthesis of toxic compounds. Two of the most pressing issues in microbial interactions are how consortia are established and how we can modulate these microbial communities to express desirable functions. Here, we propose that public goods (i.e., metabolites of high energy demand in biosynthesis) facilitate energy conservation for life under energy-limited conditions and determine the assembly and function of the consortia. Our report suggests that an

Obligations of an academic and clinical oncologist: historical reflections.

PubMed

Johnson, David H

2014-01-01

Obligations are derived from one's core values-those fundamental, enduring, deeply held beliefs that guide one's everyday actions. Gandhi stated it more eloquently than I ever could: "Your beliefs become your thoughts, your thoughts become your words, your words become your actions, your actions become your habits, your habits become your values, your values become your destiny." So what are the obligations of the academic oncologist and clinician? I believe there are a few indubitable and fundamental obligations: professionalism, patient care, stewardship, maintenance of knowledge, productivity, and mentorship). I might add that I do not see these obligations as unique to the academician but rather applicable to all physicians.

[Achievement of Sulfate-Reducing Anaerobic Ammonium Oxidation Reactor Started with Nitrate-Reducting Anaerobic Ammonium Oxidation].

PubMed

Liu, Zheng-chuan; Yuan, Lin-jiang; Zhou, Guo-biao; Li, Jing

2015-09-01

The transformation of nitrite-reducing anaerobic ammonium oxidation to sulfate-reducing anaerobic ammonium oxidation in an UASB was performed and the changes in microbial community were studied. The result showed that the sulfate reducing anaerobic ammonium oxidation process was successfully accomplished after 177 days' operation. The removal rate of ammonium nitrogen and sulfate were up to 58. 9% and 15. 7%, the removing load of ammonium nitrogen and sulfate were 74. 3 mg.(L.d)-1 and 77. 5 mg.(L.d)-1 while concentration of ammonium nitrogen and sulfate of influent were 130 mg.(L.d)-1 and 500 mg.(L.d)-1, respectively. The lost nitrogen and sulphur was around 2 in molar ratio. The pH value of the effluent was lower than that of the influent. Instead of Candidatus brocadia in nitrite reducing anaerobic ammonium oxidation granular sludge, Bacillus benzoevorans became the dominant species in sulfate reducing anaerobic ammonium oxidation sludge. The dominant bacterium in the two kinds of anaerobic ammonium oxidation process is different. Our results imply that the two anaerobic ammonium oxidation processes are carried out by different kind of bacterium.

Aerobic growth of Anoxybacillus pushchinoensis K1(T): emended descriptions of A. pushchinoensis and the genus Anoxybacillus

NASA Technical Reports Server (NTRS)

Pikuta, Elena; Cleland, David; Tang, Jane

2003-01-01

In this work, corrections are made to the descriptions of the species Anoxybacillus pushchinoensis corrig. and the genus ANOXYBACILLUS: Experiments to determine the relationship of A. pushchinoensis K1(T) to oxygen showed that it was capable of aerobic growth, but preferred to grow anaerobically. During aerobic growth, the redox indicator resazurin was reduced as a result of hydrogen gas production. The facultatively anaerobic nature of K1(T) was ascertained by cultivation in aerobic liquid medium, where growth began at the bottom of the tube. The anaerobic nature of K1(T) was also indicated by a negative catalase reaction. This work is submitted to correct the description of the species A. pushchinoensis from obligate anaerobe to aerotolerant anaerobe and to emend the description of the genus Anoxybacillus from obligate anaerobes or facultative anaerobes to aerotolerant anaerobes or facultative anaerobes.

What are the limits to the obligations of the nurse?

PubMed Central

Edwards, S D

1996-01-01

This paper enquires into the nature and the extent of the obligations of nurses. It is argued that nurses appear to be obliged to undertake supererogatory acts if they take clause one of the United Kingdom Central Council for Nursing, Midwifery and Health Visiting (UKCC) Code of Professional Conduct seriously (as, indeed, they are required to do). In the first part of the paper, the nature of nursing obligations is outlined, and then the groups and individuals to whom nurses have obligations are identified. Following a brief discussion of the moral foundation of the nurse's obligations to her/his employer, a common conflict of obligations is identified. Then a distinction is drawn between ordinary and extraordinary moral standards. Appreciation of this is necessary for an understanding of the criterion of what constitutes a supererogatory act. By the definition of supererogatory acts proposed below, it is suggested that actions such as whistleblowing satisfy that definition. PMID:8731534

12 CFR 208.111 - Obligations concerning institutional customers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... adopting sales practice rules for the government securities market, a market with a particularly broad... on their suitability obligations when making recommendations to institutional customers. (b) The... suitability obligations in making recommendations to an institutional customer are the customer's capability...

12 CFR 208.111 - Obligations concerning institutional customers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... adopting sales practice rules for the government securities market, a market with a particularly broad... on their suitability obligations when making recommendations to institutional customers. (b) The... suitability obligations in making recommendations to an institutional customer are the customer's capability...

12 CFR 208.111 - Obligations concerning institutional customers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... adopting sales practice rules for the government securities market, a market with a particularly broad... on their suitability obligations when making recommendations to institutional customers. (b) The... suitability obligations in making recommendations to an institutional customer are the customer's capability...

Brain abscess due to Aggregatibacter aphrophilus and Bacteroides uniformis.

PubMed

Bogdan, Maja; Zujić Atalić, Vlasta; Hećimović, Ivan; Vuković, Dubravka

2015-01-01

The aim of this report was to describe the occurrence of a bacterial brain abscess in a healthy individual, without any predisposing condition. A thirteen-year old boy was admitted to the Department of Neurosurgery after the onset of vomiting, headache and dizziness. A neurological deficit was detected during the physical examination so urgent magnetic resonance imaging of the brain was performed, revealing an intrahemispheric, right positioned solitary expansive mass with ring enhancement. Purulent material was obtained during osteoplastic craniotomy with total extirpation of the brain abscess. Aggregatibacter aphrophilus and Bacteroides uniformis were isolated. The patient's general condition improved and the neurological deficit subsided as a result of the prompt recognition and treatment of this life threatening condition. To achieve a favourable clinical outcome, prompt recognition and surgical treatment of a brain abscess are of primary importance,followed by administration of appropriate antimicrobial therapy. To our best knowledge, this is the first report of this combination of microorganisms as the cause of a brain abscess. Copyright © 2015 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Treatment of Neuroblastoma with an Engineered “Obligate” Anaerobic Salmonella typhimurium Strain YB1

PubMed Central

Ning, Bo-Tao; Yu, Bin; Chan, Shing; Chan, Jian-liang; Huang, Jian-Dong; Chan, Godfrey Chi-Fung

2017-01-01

Purpose Neuroblastoma is an embryonic solid tumor derived from the progenitors of the sympathetic nervous system. More than half of the patients developed metastatic disease at the time of initial diagnosis and had poor outcome with current therapeutic approaches. In recent years, some obligate and facultative anaerobic bacteria were reported to target the hypoxic and necrotic region of solid tumor models and caused tumor regression. We recently successfully constructed an “obligate” anaerobic Salmonella strain YB1 that was applied in breast cancer nude mice model by us. Here, we report the application of YB1 in neuroblastoma treatment. Methods The anti-cancer effect and side-effects of YB1 was examined in both in vitro and in vivo experiment. Previous established orthotopic neuroblastoma SCID/beige murine model using SK-NLP/luciferase cell line was adopted. Results In vitro, YB1 induced apoptosis for up to 31.4% of the neuroblastoma cells under anaerobic condition, three times more than that under aerobic condition (10.9%). The expression of both Toll like Receptor 4 and 5 (TLR4 and TLR5) in cancer cells were significantly up-regulated (p<0.05, p<0.01 respectively) after the treatment of YB1 under anaerobic condition. In mouse model, YB1 preferentially accumulated inside the core of the tumors, rather than in normal tissues as our previous reported. This is suggestive of the hypoxic nature of tumor core. Tumor growth was significantly retarded in YB1 treatment group (n=6, P<0.01). Furthermore, there was no long-term organ damage noted in all the organs examined including heart, lung, liver, spleen and brain in the YB1 treated mice. Conclusion The genetic modified Salmonella strain YB1 is a promising anti-tumor strategy against the tumor bulk for neuroblastoma. Future study can be extended to other common cancer types to verify the relative efficacy on different neoplastic cells. PMID:28775780

Livestock Anaerobic Digester Database

EPA Pesticide Factsheets

The Anaerobic Digester Database provides basic information about anaerobic digesters on livestock farms in the United States, organized in Excel spreadsheets. It includes projects that are under construction, operating, or shut down.

12 CFR 13.100 - Obligations concerning institutional customers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... market, a market with a particularly broad institutional component. Accordingly, the OCC believes it is appropriate to provide further guidance to banks on their suitability obligations when making recommendations... suitability obligations in making recommendations to an institutional customer are the customer's capability...

12 CFR 368.100 - Obligations concerning institutional customers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... securities market, a market with a particularly broad institutional component. Accordingly, the FDIC believes it is appropriate to provide further guidance to banks on their suitability obligations when making... important considerations in determining the scope of a bank's suitability obligations in making...

12 CFR 368.100 - Obligations concerning institutional customers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... securities market, a market with a particularly broad institutional component. Accordingly, the FDIC believes it is appropriate to provide further guidance to banks on their suitability obligations when making... important considerations in determining the scope of a bank's suitability obligations in making...

12 CFR 13.100 - Obligations concerning institutional customers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... market, a market with a particularly broad institutional component. Accordingly, the OCC believes it is appropriate to provide further guidance to banks on their suitability obligations when making recommendations... suitability obligations in making recommendations to an institutional customer are the customer's capability...

Alterations of Bacteroides sp., Neisseria sp., Actinomyces sp., and Streptococcus sp. populations in the oropharyngeal microbiome are associated with liver cirrhosis and pneumonia.

PubMed

Lu, Haifeng; Qian, Guirong; Ren, Zhigang; Zhang, Chunxia; Zhang, Hua; Xu, Wei; Ye, Ping; Yang, Yunmei; Li, Lanjuan

2015-06-23

The microbiomes of humans are associated with liver and lung inflammation. We identified and verified alterations of the oropharyngeal microbiome and assessed their association with cirrhosis and pneumonia. Study components were as follows: (1) determination of the temporal stability of the oropharyngeal microbiome; (2) identification of oropharyngeal microbial variation in 90 subjects; (3) quantitative identification of disease-associated bacteria. DNAs enriched in bacterial sequences were produced from low-biomass oropharyngeal swabs using whole genome amplification and were analyzed using denaturing gradient gel electrophoresis analysis. Whole genome amplification combined with denaturing gradient gel electrophoresis analysis monitored successfully oropharyngeal microbial variations and showed that the composition of each subject's oropharyngeal microbiome remained relatively stable during the follow-up. The microbial composition of cirrhotic patients with pneumonia differed from those of others and clustered together in subgroup analysis. Further, species richness and the value of Shannon's diversity and evenness index increased significantly in patients with cirrhosis and pneumonia versus others (p < 0.001, versus healthy controls; p < 0.01, versus cirrhotic patients without pneumonia). Moreover, we identified variants of Bacteroides, Eubacterium, Lachnospiraceae, Neisseria, Actinomyces, and Streptococcus through phylogenetic analysis. Quantitative polymerase chain reaction assays revealed that the populations of Bacteroides, Neisseria, and Actinomycetes increased, while that of Streptococcus decreased in cirrhotic patients with pneumonia versus others (p < 0.001, versus Healthy controls; p < 0.01, versus cirrhotic patients without pneumonia). Alterations of Bacteroides, Neisseria, Actinomyces, and Streptococcus populations in the oropharyngeal microbiome were associated with liver cirrhosis and pneumonia.

Microbial diversity associated with the anaerobic sediments of a soda lake (Mono Lake, California, USA).

PubMed

Rojas, Patricia; Rodríguez, Nuria; de la Fuente, Vicenta; Sánchez-Mata, Daniel; Amils, Ricardo; Sanz, José L

2018-06-01

Soda lakes are inhabited by important haloalkaliphilic microbial communities that are well adapted to these extreme characteristics. The surface waters of the haloalkaline Mono Lake (California, USA) are alkaline but, in contrast to its bottom waters, do not present high salinity. We have studied the microbiota present in the shoreline sediments of Mono Lake using next-generation sequencing techniques. The statistical indexes showed that Bacteria had a higher richness, diversity, and evenness than Archaea. Seventeen phyla and 8 "candidate divisions" were identified among the Bacteria, with a predominance of the phyla Firmicutes, Proteobacteria, and Bacteroidetes. Among the Proteobacteria, there was a notable presence of Rhodoplanes and a high diversity of sulfate-reducing Deltaproteobacteria, in accordance with the high sulfate-reducing activity detected in soda lakes. Numerous families of bacterial fermenters were identified among the Firmicutes. The Bacteroides were represented by several environmental groups that have not yet been isolated. Since final organic matter in anaerobic environments with high sulfate contents is mineralized mainly by sulfate-reducing bacteria, very little methanogenic archaeal biodiversity was detected. Only 2 genera, Methanocalculus and Methanosarcina, were retrieved. The species similarities described indicate that a significant number of the operational taxonomic units identified may represent new species.

Bacteroides gingivalis-Actinomyces viscosus cohesive interactions as measured by a quantitative binding assay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwarz, S.; Ellen, R.P.; Grove, D.A.

1987-10-01

There is limited evidence, mostly indirect, to suggest that the adherence of Bacteroides gingivalis to teeth may be enhanced by the presence of gram-positive dental plaque bacteria like Actinomyces viscosus. The purpose of this study was to carry out direct quantitative assessments of the cohesion of B gingivalis and A. viscosus by using an in vitro assay modeled on the natural sequence in which these two species colonize the teeth. The assay allowed comparisons to be made of the adherence of /sup 3/H-labeled B. gingivalis 2561 and 381 to saliva-coated hydroxyapatite beads (S-HA) and A. viscosus WVU627- or T14V-coated S-HAmore » (actinobeads) in equilibrium and kinetics binding studies. A series of preliminary binding studies with 3H-labeled A. viscosus and parallel studies by scanning electron microscopy with unlabeled A. viscosus were conducted to establish a protocol by which actinobeads suitable for subsequent Bacteroides adherence experiments could be prepared. By scanning electron microscopy, the actinobeads had only small gaps of exposed S-HA between essentially irreversibly bound A. viscosus cells. Furthermore, B. gingivalis cells appeared to bind preferentially to the Actinomyces cells instead of the exposed S-HA. B. gingivalis binding to both S-HA and actinobeads was saturable with at least 2 X 10(9) to 3 X 10(9) cells per ml, and equilibrium with saturating concentrations was reached within 10 to 20 min. B. gingivalis always bound in greater numbers to the actinobeads than to S-HA. These findings provide direct measurements supporting the concept that cohesion with dental plaque bacteria like A. viscosus may foster the establishment of B. gingivalis on teeth by enhancing its adherence.« less

26 CFR 1.103-4 - Interest upon United States obligations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 2 2011-04-01 2011-04-01 false Interest upon United States obligations. 1.103-4... Interest upon United States obligations. (a) Issued before March 1, 1941. (1) Interest upon obligations of the United States issued on or before September 1, 1917, is exempt from tax. In the case of...

26 CFR 1.103-4 - Interest upon United States obligations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Interest upon United States obligations. 1.103-4... Interest upon United States obligations. (a) Issued before March 1, 1941. (1) Interest upon obligations of the United States issued on or before September 1, 1917, is exempt from tax. In the case of...

7 CFR 400.166 - Obligations of the Corporation.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 6 2013-01-01 2013-01-01 false Obligations of the Corporation. 400.166 Section 400... CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE REGULATIONS Reinsurance Agreement-Standards for... Corporation. The Agreement will include the following among the obligations of the Corporation. (a) The...

7 CFR 400.166 - Obligations of the Corporation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 6 2012-01-01 2012-01-01 false Obligations of the Corporation. 400.166 Section 400... CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE REGULATIONS Reinsurance Agreement-Standards for... Corporation. The Agreement will include the following among the obligations of the Corporation. (a) The...

7 CFR 400.166 - Obligations of the Corporation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Obligations of the Corporation. 400.166 Section 400... CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE REGULATIONS Reinsurance Agreement-Standards for... Corporation. The Agreement will include the following among the obligations of the Corporation. (a) The...

7 CFR 400.166 - Obligations of the Corporation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 6 2014-01-01 2014-01-01 false Obligations of the Corporation. 400.166 Section 400... CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE REGULATIONS Reinsurance Agreement-Standards for... Corporation. The Agreement will include the following among the obligations of the Corporation. (a) The...

7 CFR 400.166 - Obligations of the Corporation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 6 2011-01-01 2011-01-01 false Obligations of the Corporation. 400.166 Section 400... CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE REGULATIONS Reinsurance Agreement-Standards for... Corporation. The Agreement will include the following among the obligations of the Corporation. (a) The...

Resistance of Bacteroides isolates recovered among clinical samples from a major Costa Rican hospital between 2000 and 2008 to ß-lactams, clindamycin, metronidazole, and chloramphenicol.

PubMed

Cordero-Laurent, E; Rodríguez, C; Rodríguez-Cavallini, E; Gamboa-Coronado, M M; Quesada-Gómez, C

2012-12-01

To assess the susceptibility of 100 isolates of Bacteroides spp. recovered in a major Costa Rican hospital between 2000 and 2008 to several ß-lactams, chloramphenicol, clindamycin and metronidazole. Susceptibility to amoxicillin, amoxicillin with clavulanic acid, piperacillin, piperacillin with tazobactam, ticarcillin, ticarcillin with clavulanic acid, cefoxitin, cefotetan, imipenem, chloramphenicol, clindamycin, and metronidazole was determined with the ATB ANA® system. In addition, minimum inhibitory concentrations (MIC) of clindamycin and metronidazole were determined with the broth microdilution method because these drugs are the treatment of choice for anaerobic infections in Costa Rica. Reference strains ATCC® 25285 and ATCC® 29741 were employed as indicated. According to the ATB ANA® system, 93 isolates were resistant to at least one antibiotic. Resistance to ß-lactams was common. By contrast, resistance to ß-lactams supplemented with ß-lactamase inhibitors was rare. All of the strains were inhibited by imipenem and chloramphenicol. By a broth microdilución test, resistance to clindamycin was 20%, with MIC ranging from 64 mg/L to 256 mg/L; all of the strains were susceptible to metronidazole. The high MIC for clindamycin obtained for the majority of the resistant strains is highly suggestive of the presence of mechanisms of acquired resistance among the isolates, therefore surveillance studies are required to determine its efficacy. The low resistance to metronidazole observed underlines its value as a first-line drug. On the other hand, imipenem could be used to treat infections that do not respond well to metronidazole or clindamycin.

Economic viability of anaerobic digestion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wellinger, A.

1996-01-01

The industrial application of anaerobic digestion is a relatively new, yet proven waste treatment technology. Anaerobic digestion reduces and upgrades organic waste, and is a good way to control air pollution as it reduces methane and nitrous gas emissions. For environmental and energy considerations, anaerobic digestion is a nearly perfect waste treatment process. However, its economic viability is still in question. A number of parameters - type of waste (solid or liquid), digester system, facility size, product quality and end use, environmental requirements, cost of alternative treatments (including labor), and interest rates - define the investment and operating costs ofmore » an anaerobic digestion facility. Therefore, identical facilities that treat the same amount and type of waste may, depending on location, legislation, and end product characteristics, reveal radically different costs. A good approach for evaluating the economics of anaerobic digestion is to compare it to treatment techniques such as aeration or conventional sewage treatment (for industrial wastewater), or composting and incineration (for solid organic waste). For example, the cost (per ton of waste) of in-vessel composting with biofilters is somewhat higher than that of anaerobic digestion, but the investment costs 1 1/2 to 2 times more than either composting or anaerobic digestion. Two distinct advantages of anaerobic digestion are: (1) it requires less land than either composting or incinerating, which translates into lower costs and milder environmental and community impacts (especially in densely populated areas); and (2) it produces net energy, which can be used to operate the facility or sold to nearby industries.« less

7 CFR 783.7 - Obligations of a participant.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Obligations of a participant. 783.7 Section 783.7 Agriculture Regulations of the Department of Agriculture (Continued) FARM SERVICE AGENCY, DEPARTMENT OF AGRICULTURE SPECIAL PROGRAMS TREE ASSISTANCE PROGRAM § 783.7 Obligations of a participant. (a) Eligible...

Doubly distributing special obligations: what professional practice can learn from parenting

PubMed Central

Tilburt, Jon; Brody, Baruch

2018-01-01

A traditional ethic of medicine asserts that physicians have special obligations to individual patients with whom they have a clinical relationship. Contemporary trends in US healthcare financing like bundled payments seem to threaten traditional conceptions of special obligations of individual physicians to individual patients because their population-based focus sets a tone that seems to emphasise responsibilities for groups of patients by groups of physicians in an organisation. Prior to undertaking a cogent debate about the fate and normative weight of special obligations and a traditional ethic for contemporary healthcare, we need a deeper examination of what the traditional ethic of special obligations really means. Here we offer a conception of ‘doubly distributed’ special obligations. Physicians and similarly minded healing professionals abiding by a traditional ethic have always spread their devotion and attention across multiple patients and have shared responsibilities with physician and non-physician colleagues in much the same way devoted parents have frequently distributed their special obligations across multiple children and across multiple parents. By taking up the extended analogy of parent we argue that doubly distributing special obligations need not contradict the possibility of special obligations in restructured collective forms of healthcare delivery and financing. PMID:27125989

12 CFR 612.2270 - Purchase of System obligations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Purchase of System obligations. 612.2270... REFERRAL OF KNOWN OR SUSPECTED CRIMINAL VIOLATIONS Standards of Conduct § 612.2270 Purchase of System... Funding Corporation, may only purchase joint, consolidated, or Systemwide obligations that are: (1) Part...

Isolation, growth, and metabolism of an obligately anaerobic, selenate- respiring bacterium, strain SES-3

USGS Publications Warehouse

Oremland, R.S.; Blum, J.S.; Culbertson, C.W.; Visscher, P.T.; Miller, L.G.; Dowdle, P.; Strohmaier, F.E.

1994-01-01

A gram-negative, strictly anaerobic, motile vibrio was isolated from a selenate-respiring enrichment culture. The isolate, designated strain SES-3, grew by coupling the oxidation of lactate to acetate plus CO2 with the concomitant reduction of selenate to selenite or of nitrate to ammonium. No growth was observed on sulfate or selenite, but cell suspensions readily reduced selenite to elemental selenium (Se0). Hence, SES-3 can carry out a complete reduction of selenate to Se0. Washed cell suspensions of selenate- grown cells did not reduce nitrate, and nitrate-grown cells did not reduce selenate, indicating that these reductions are achieved by separate inducible enzyme systems. However, both nitrate-grown and selenate-grown cells have a constitutive ability to reduce selenite or nitrite. The oxidation of [14C]lactate to 14CO2 coupled to the reduction of selenate or nitrate by cell suspensions was inhibited by CCCP (carbonyl cyanide m- chlorophenylhydrazone), cyanide, and azide. High concentrations of selenite (5 mM) were readily reduced to Se0 by selenate-grown cells, but selenite appeared to block the synthesis of pyruvate dehydrogenase. Tracer experiments with [75Se]selenite indicated that cell suspensions could achieve a rapid and quantitative reduction of selenite to Se0. This reduction was totally inhibited by sulfite, partially inhibited by selenate or nitrite, but unaffected by sulfate or nitrate. Cell suspensions could reduce thiosulfate, but not sulfite, to sulfide. These results suggest that reduction of selenite to Se0 may proceed, in part, by some of the components of a dissimilatory system for sulfur oxyanions.

Incorporation of leucine into phospholipids of Bacteroides thetaiotaomicron.

PubMed Central

Smith, R D; Salyers, A A

1981-01-01

L-[4,5-3H]- or L-[U-14C]leucine was incorporated by Bacteroides thetaiotaomicron into acid-precipitable material even when the bacteria were treated with concentrations of tetracycline high enough to prevent growth. Similar results were obtained when L-[2,3,4-3H]valine or L-[4,5-3H]isoleucine was used instead of leucine. In bacteria which had been treated with tetracycline, the acid-precipitable label was not solubilized by treatment with protease, lysozyme, or deoxyribonuclease. However, virtually all of the label was extractable with chloroform-methanol, indicating that the label had been incorporated into membrane lipids. Since L-[1-14C]leucine was not incorporated into lipids, leucine was probably decarboxylated before incorporation. When a chloroform extract from bacteria which had been labeled with both [32P]phosphate and [3H]leucine was resolved into component phospholipids by two-dimensional thin-layer chromatography, 3H was incorporated into all of the phospholipids. When these phospholipids were deacylated, the 3H from leucine was associated with released fatty acids rather than with the head groups. Thus, it appears that B. thetaiotaomicron can utilize leucine and similar amino acids not only by incorporating them into protein but also by incorporating portions of these amino acids into membrane phospholipids. PMID:7462155

Anaerobic thermophilic culture

DOEpatents

Ljungdahl, Lars G.; Wiegel, Jurgen K. W.

1981-01-01

A newly discovered thermophilic anaerobe is described that was isolated in a biologically pure culture and designated Thermoanaerobacter ethanolicus ATCC 3/550. T. Ethanolicus is cultured in aqueous nutrient medium under anaerobic, thermophilic conditions and is used in a novel process for producing ethanol by subjecting carbohydrates, particularly the saccharides, to fermentation action of the new microorganism in a biologically pure culture.

Monoclonal antibody against a serotype antigen of Porphyromonas (Bacteroides) endodontalis and characteristics of the antigen.

PubMed Central

Hanazawa, S; Sagiya, T; Amano, S; Nishikawa, H; Kitano, S

1990-01-01

Recent studies have demonstrated the presence of three serotypes (O1K1, O1K2, and O1K-) of Porphyromonas (Bacteroides) endodontalis. In the present study, a hybridoma cell line producing monoclonal antibody (BEE11) specific for serotype O1K1 of P. endodontalis was established. The specificity of the antibody was evaluated by enzyme-linked immunosorbent assay and immunoslot blot analysis. BEE11 antibody reacted with strains ATCC 35406, HG 400, and HG 421 of the bacterium. However, it did not react with HG 422 or HG 948. Also, the antibody did not react with any of the black-pigmented Bacteroides strains tested. Although the antibody reacted with total cell envelope and capsule materials, it did not do so with lipopolysaccharide. The antibody reacted with antigen material having a molecular mass of 110 kilodaltons (kDa), as judged from fractionation by Superose 12 prep gel chromatography. When the peak fraction from the Superose 12 column was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot (immunoblot) analysis, the reactivity was detected as a single band at an apparent molecular mass of about 52 kDa. The antigen material purified partially by high-performance liquid chromatography was sensitive to trypsin, V8 protease, and heating to 80 degrees C but not to neuraminidase. Therefore, the present study shows that BEE11 antibody recognizes a serotype antigen of P. endodontalis which may be a dimer consisting of monomers having molecular masses of approximately 52 kDa and sensitivity to proteases and heat. Images PMID:2370106

47 CFR 27.1184 - Triggering a reimbursement obligation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... reimbursement obligation. (a) The clearinghouse will apply the following test to determine when an AWS entity has triggered a cost-sharing obligation and therefore must pay an AWS relocator of a BRS system in... co-channel with the licensed AWS band(s) of the AWS entity; (2) An AWS relocator has paid the...

Deconfounding Distance Effects in Judgments of Moral Obligation

ERIC Educational Resources Information Center

Nagel, Jonas; Waldmann, Michael R.

2013-01-01

A heavily disputed question of moral philosophy is whether spatial distance between agent and victim is normatively relevant for the degree of obligation to help strangers in need. In this research, we focus on the associated descriptive question whether increased distance does in fact reduce individuals' sense of helping obligation. One problem…

29 CFR 4043.20 - Post-Event filing obligation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 9 2010-07-01 2010-07-01 false Post-Event filing obligation. 4043.20 Section 4043.20 Labor... EVENTS AND CERTAIN OTHER NOTIFICATION REQUIREMENTS Post-Event Notice of Reportable Events § 4043.20 Post-Event filing obligation. The plan administrator and each contributing sponsor of a plan for which a...

29 CFR 4043.20 - Post-Event filing obligation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 9 2014-07-01 2014-07-01 false Post-Event filing obligation. 4043.20 Section 4043.20 Labor... EVENTS AND CERTAIN OTHER NOTIFICATION REQUIREMENTS Post-Event Notice of Reportable Events § 4043.20 Post-Event filing obligation. The plan administrator and each contributing sponsor of a plan for which a...

29 CFR 4043.20 - Post-Event filing obligation.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 9 2013-07-01 2013-07-01 false Post-Event filing obligation. 4043.20 Section 4043.20 Labor... EVENTS AND CERTAIN OTHER NOTIFICATION REQUIREMENTS Post-Event Notice of Reportable Events § 4043.20 Post-Event filing obligation. The plan administrator and each contributing sponsor of a plan for which a...

29 CFR 4043.20 - Post-Event filing obligation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 9 2012-07-01 2012-07-01 false Post-Event filing obligation. 4043.20 Section 4043.20 Labor... EVENTS AND CERTAIN OTHER NOTIFICATION REQUIREMENTS Post-Event Notice of Reportable Events § 4043.20 Post-Event filing obligation. The plan administrator and each contributing sponsor of a plan for which a...

29 CFR 4043.20 - Post-Event filing obligation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 9 2011-07-01 2011-07-01 false Post-Event filing obligation. 4043.20 Section 4043.20 Labor... EVENTS AND CERTAIN OTHER NOTIFICATION REQUIREMENTS Post-Event Notice of Reportable Events § 4043.20 Post-Event filing obligation. The plan administrator and each contributing sponsor of a plan for which a...

Paradoxical anaerobism in desert pupfish.

PubMed

Heuton, Matt; Ayala, Luis; Burg, Chris; Dayton, Kyle; McKenna, Ken; Morante, Aldo; Puentedura, Georgina; Urbina, Natasha; Hillyard, Stanley; Steinberg, Spencer; van Breukelen, Frank

2015-12-01

In order to estimate metabolic demands of desert pupfish for conservation purposes, we measured oxygen consumption in fish acclimated to the ecologically relevant temperatures of 28 or 33°C. For these experiments, we used fish derived from a refuge population of Devils Hole pupfish (Cyprinodon diabolis). Measurement of routine oxygen consumption (V̇O2,routine) revealed some 33°C-acclimated fish (10% of 295 assayed fish) periodically exhibited periods of no measurable oxygen consumption despite available ambient oxygen tensions that were above the critical PO2. We call this phenomenon paradoxical anaerobism. The longest observed continuous bout with no oxygen consumption was 149 min, although typical bouts were much shorter. Fish maintained normal posture and ventilation rate (>230 ventilations per minute) during paradoxical anaerobism. Fish rarely demonstrated a compensatory increase in oxygen use following a period of paradoxical anaerobism. In contrast, only one out of 262 sampled fish acclimated at 28°C spontaneously demonstrated paradoxical anaerobism. Muscle lactate concentration was not elevated during periods of paradoxical anaerobism. However, the amount of ethanol released by the 33°C-acclimated fish was 7.3 times greater than that released by the 28°C acclimation group, suggesting ethanol may be used as an alternative end product of anaerobic metabolism. Exposure to exogenous ethanol, in concentrations as low as 0.1%, produced periods of paradoxical anaerobism even in 28°C-acclimated fish. © 2015. Published by The Company of Biologists Ltd.

Growth of the facultative anaerobe Shewanella putrefaciens by elemental sulfur reduction

NASA Technical Reports Server (NTRS)

Moser, D. P.; Nealson, K. H.

1996-01-01

The growth of bacteria by dissimilatory elemental sulfur reduction is generally associated with obligate anaerobes and thermophiles in particular. Here we describe the sulfur-dependent growth of the facultatively anaerobic mesophile Shewanella putrefaciens. Six of nine representative S. putrefaciens isolates from a variety of environments proved able to grow by sulfur reduction, and strain MR-1 was chosen for further study. Growth was monitored in a minimal medium (usually with 0.05% Casamino Acids added as a growth stimulant) containing 30 mM lactate and limiting concentrations of elemental sulfur. When mechanisms were provided for the removal of the metabolic end product, H2S, measurable growth was obtained at sulfur concentrations of from 2 to 30 mM. Initial doubling times were ca. 1.5 h and substrate independent over the range of sulfur concentrations tested. In the cultures with the highest sulfur concentrations, cell numbers increased by greater than 400-fold after 48 h, reaching a maximum density of 6.8 x 10(8) cells ml-1. Yields were determined as total cell carbon and ranged from 1.7 to 5.9 g of C mol of S(0) consumed-1 in the presence of the amino acid supplement and from 0.9 to 3.4 g of C mol of S(0-1) in its absence. Several lines of evidence indicate that cell-to-sulfur contact is not required for growth. Approaches for the culture of sulfur-metabolizing bacteria and potential ecological implications of sulfur reduction in Shewanella-like heterotrophs are discussed.

An Extended Role-Based Access Control Model for Delegating Obligations

NASA Astrophysics Data System (ADS)

Ben-Ghorbel-Talbi, Meriam; Cuppens, Frédéric; Cuppens-Boulahia, Nora; Bouhoula, Adel

The main aim of access control models is to provide means to simplify the management of the security policy, which is a fastidious and error-prone task. Supporting delegation is considered as an important mean to decentralize the administration and therefore to allow security policy to be more flexible and easier to manipulate. Our main contribution is the proposition of a unified model to the administration and delegation of obligations. Managing such delegations implies more requirements than managing traditional privileges delegation. In fact, delegating obligations may include two interpretations: the delegation of the obligation and the delegation of the responsibility related to this obligation. Therefore, it is important to deal with these two notions separately. Moreover, since delegating an obligation involves the delegation of sanctions, then the consent of the user who receives this delegation may be required in some cases. We address in this paper these requirements and we propose a formalism to deal with them.

Anaerobic bacteria grow within Candida albicans biofilms and induce biofilm formation in suspension cultures.

PubMed

Fox, Emily P; Cowley, Elise S; Nobile, Clarissa J; Hartooni, Nairi; Newman, Dianne K; Johnson, Alexander D

2014-10-20

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multiple mobile promoter regions for the rare carbapenem resistance gene of Bacteroides fragilis.

PubMed

Podglajen, I; Breuil, J; Rohaut, A; Monsempes, C; Collatz, E

2001-06-01

Two novel insertion sequences (IS), IS1187 and IS1188, are described upstream from the carbapenem resistance gene cfiA in strains of Bacteroides fragilis. Mapping, with the RACE procedure, of transcription start sites of cfiA in these and two other previously reported IS showed that transcription of this rarely encountered gene is initiated close to a variety of B. fragilis consensus promoter sequences, as recently defined (D. P. Bayley, E. R. Rocha, and C. J. Smith, FEMS Microbiol. Lett. 193:149-154, 2000). In the cases of IS1186 and IS1188, these sequences overlap with putative Esigma(70) promoter sequences, while in IS942 and IS1187 such sequences can be observed either upstream or downstream of the B. fragilis promoters.

19 CFR 4.94 - Yacht privileges and obligations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 1 2011-04-01 2011-04-01 false Yacht privileges and obligations. 4.94 Section 4... THE TREASURY VESSELS IN FOREIGN AND DOMESTIC TRADES General § 4.94 Yacht privileges and obligations...) A cruising license may be issued to a yacht of a foreign country only if it has been made to appear...

19 CFR 4.94 - Yacht privileges and obligations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Yacht privileges and obligations. 4.94 Section 4... THE TREASURY VESSELS IN FOREIGN AND DOMESTIC TRADES General § 4.94 Yacht privileges and obligations...) A cruising license may be issued to a yacht of a foreign country only if it has been made to appear...

Engineering of obligate intracellular bacteria: progress, challenges and paradigms

USDA-ARS?s Scientific Manuscript database

Over twenty years have passed since the first report of genetic manipulation of an obligate intracellular bacterium. Through progress interspersed by bouts of stagnation, microbiologists and geneticists have developed approaches to genetically manipulate obligates. A brief overview of the current ge...

Anaerobic prosthetic joint infection.

PubMed

Shah, Neel B; Tande, Aaron J; Patel, Robin; Berbari, Elie F

2015-12-01

In an effort to improve mobility and alleviate pain from degenerative and connective tissue joint disease, an increasing number of individuals are undergoing prosthetic joint replacement in the United States. Joint replacement is a highly effective intervention, resulting in improved quality of life and increased independence [1]. By 2030, it is predicted that approximately 4 million total hip and knee arthroplasties will be performed yearly in the United States [2]. One of the major complications associated with this procedure is prosthetic joint infection (PJI), occurring at a rate of 1-2% [3-7]. In 2011, the Musculoskeletal Infectious Society created a unifying definition for prosthetic joint infection [8]. The following year, the Infectious Disease Society of America published practice guidelines that focused on the diagnosis and management of PJI. These guidelines focused on the management of commonly encountered organisms associated with PJI, including staphylococci, streptococci and select aerobic Gram-negative bacteria. However, with the exception of Propionibacterium acnes, management of other anaerobic organisms was not addressed in these guidelines [1]. Although making up approximately 3-6% of PJI [9,10], anaerobic microorganisms cause devastating complications, and similar to the more common organisms associated with PJI, these bacteria also result in significant morbidity, poor outcomes and increased health-care costs. Data on diagnosis and management of anaerobic PJI is mostly derived from case reports, along with a few cohort studies [3]. There is a paucity of published data outlining factors associated with risks, diagnosis and management of anaerobic PJI. We therefore reviewed available literature on anaerobic PJI by systematically searching the PubMed database, and collected data from secondary searches to determine information on pathogenesis, demographic data, clinical features, diagnosis and management. We focused our search on five commonly

Obligations of low income countries in ensuring equity in global health financing.

PubMed

Barugahare, John; Lie, Reidar K

2015-09-08

Despite common recognition of joint responsibility for global health by all countries particularly to ensure justice in global health, current discussions of countries' obligations for global health largely ignore obligations of developing countries. This is especially the case with regards to obligations relating to health financing. Bearing in mind that it is not possible to achieve justice in global health without achieving equity in health financing at both domestic and global levels, our aim is to show how fulfilling the obligation we propose will make it easy to achieve equity in health financing at both domestic and international levels. Achieving equity in global health financing is a crucial step towards achieving justice in global health. Our general view is that current discussions on global health equity largely ignore obligations of Low Income Country (LIC) governments and we recommend that these obligations should be mainstreamed in current discussions. While we recognise that various obligations need to be fulfilled in order to ultimately achieve justice in global health, for lack of space we prioritise obligations for health financing. Basing on the evidence that in most LICs health is not given priority in annual budget allocations, we propose that LIC governments should bear an obligation to allocate a certain minimum percent of their annual domestic budget resources to health, while they await external resources to supplement domestic ones. We recommend and demonstrate a mechanism for coordinating this obligation so that if the resulting obligations are fulfilled by both LIC and HIC governments it will be easy to achieve equity in global health financing. Although achieving justice in global health will depend on fulfillment of different categories of obligations, ensuring inter- and intra-country equity in health financing is pivotal. This can be achieved by requiring all LIC governments to allocate a certain optimal per cent of their domestic

Anaerobic biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons by a facultative anaerobe Pseudomonas sp. JP1.

PubMed

Liang, Lei; Song, Xiaohui; Kong, Jing; Shen, Chenghui; Huang, Tongwang; Hu, Zhong

2014-11-01

Polycyclic aromatic hydrocarbons (PAHs) are harmful persistent organic pollutants, while the high-molecular-weight (HMW) PAHs are even more detrimental to the environment and human health. However, microbial anaerobic degradation of HMW PAHs has rarely been reported. One facultative anaerobe Pseudomonas sp. JP1 was isolated from Shantou Bay, Shantou, China, which could degrade a variety of HMW PAHs. After 40 days cultivation with strain JP1, anaerobic biodegradation rate of benzo[a]pyrene (BaP), fluoranthene, and phenanthrene was 30, 47, and 5 %, respectively. Consumption of nitrate as the electron acceptor was confirmed by N-(1-naphthyl) ethylenediamine spectrophotometry. Supplementation of sodium sulfite, maltose, or glycine, and in a salinity of 0-20 ‰ significantly stimulated anaerobic degradation of BaP. Lastly, the anaerobic degradation metabolites of BaP by strain JP1 were investigated using GC/MS, and the degradation pathway was proposed. This study is helpful for further studies on the mechanism of anaerobic biodegradation of PAHs.

18 CFR 292.311 - Reinstatement of obligation to purchase.

Code of Federal Regulations, 2010 CFR

2010-04-01

... electric energy, a qualifying cogeneration facility, a qualifying small power production facility, a State... utility's obligation to purchase electric energy under this section. Such application shall set forth the... application reinstating the electric utility's obligation to purchase electric energy under this section if...

18 CFR 292.311 - Reinstatement of obligation to purchase.

Code of Federal Regulations, 2011 CFR

2011-04-01

... electric energy, a qualifying cogeneration facility, a qualifying small power production facility, a State... utility's obligation to purchase electric energy under this section. Such application shall set forth the... application reinstating the electric utility's obligation to purchase electric energy under this section if...

Normal bacterial flora from vaginas of Criollo Limonero cows.

PubMed

Zambrano-Nava, Sunny; Boscán-Ocando, Julio; Nava, Jexenia

2011-02-01

In order to describe the normal bacterial flora in vaginas of Criollo Limonero cows, 51 healthy multiparous cows, at least 90-day postpartum, were selected. Duplicated swabs (N = 102) were taken from the vaginal fornix of cows to perform aerobic and anaerobic cultures as well as conventional biochemical tests. Out of 102 swabs, bacterial growth was obtained in 55 (53.9%) while the remaining 47 (46.1%) did not exhibited any bacterial growth. Of the 55 bacterial growths, 23 (41.8%) were aerobic whereas 32 (58.1%) were anaerobic. Likewise, 29 (52.72%) of bacterial growths were pure and 26 (47.27%) were mixed. Under both aerobic and anaerobic conditions, Gram positive bacteria were predominant (81.82% and 73.08%, respectively) over Gram negative bacteria (18.18% and 26.92%, respectively). Isolated bacteria were Arcanobacterium pyogenes (22.92%), Staphylococcus aureus (15.63%), Staphylococcus coagulase negative (17.71%), Erysipelothrix rhusiopathiae (6.25%), Bacteroides spp. (13.54%), and Peptostreptococcus spp. (7.29%). In conclusion, normal vaginal bacterial flora of Criollo Limonero cows was predominantly Gram positive and included A. pyogenes, S. aureus, coagulase negative Staphylococcus, E. rhusiopathiae, Bacteroides spp., and Peptostreptococcus spp. In Criollo Limonero cattle, adaptive aspects such as development of humoral and physical mechanisms for defense, and bacterial adaptation to host deserve research attention.

Wingate Anaerobic Test Peak Power and Anaerobic Capacity Classification for Men and Women Intercollegiate Athletes

DTIC Science & Technology

2009-12-01

Dawson, LH, Wile , AL, Payn, TL, and Hannon, ME. Wingate Anaerobic Test peak power and anaerobic capacity classifications for men and women...139,2007. 6. Chromiah JA, Smedley, B, Carpenter, W, Brown , R, Koh, YS, Lamberth, JG, Joe, LA, Abadie, BR, and Altorfer, G. Effect of 10- week strength...Bnt J Sport Med 38: 784-789,2004. 8. Findley, BW, Brown , LE, and Whitehurst, M. Anaerobic power performance ofincumbent female firefrghters. J

Atmospheric vs. anaerobic processing of metabolome samples for the metabolite profiling of a strict anaerobic bacterium, Clostridium acetobutylicum.

PubMed

Lee, Sang-Hyun; Kim, Sooah; Kwon, Min-A; Jung, Young Hoon; Shin, Yong-An; Kim, Kyoung Heon

2014-12-01

Well-established metabolome sample preparation is a prerequisite for reliable metabolomic data. For metabolome sampling of a Gram-positive strict anaerobe, Clostridium acetobutylicum, fast filtration and metabolite extraction with acetonitrile/methanol/water (2:2:1, v/v) at -20°C under anaerobic conditions has been commonly used. This anaerobic metabolite processing method is laborious and time-consuming since it is conducted in an anaerobic chamber. Also, there have not been any systematic method evaluation and development of metabolome sample preparation for strict anaerobes and Gram-positive bacteria. In this study, metabolome sampling and extraction methods were rigorously evaluated and optimized for C. acetobutylicum by using gas chromatography/time-of-flight mass spectrometry-based metabolomics, in which a total of 116 metabolites were identified. When comparing the atmospheric (i.e., in air) and anaerobic (i.e., in an anaerobic chamber) processing of metabolome sample preparation, there was no significant difference in the quality and quantity of the metabolomic data. For metabolite extraction, pure methanol at -20°C was a better solvent than acetonitrile/methanol/water (2:2:1, v/v/v) at -20°C that is frequently used for C. acetobutylicum, and metabolite profiles were significantly different depending on extraction solvents. This is the first evaluation of metabolite sample preparation under aerobic processing conditions for an anaerobe. This method could be applied conveniently, efficiently, and reliably to metabolome analysis for strict anaerobes in air. © 2014 Wiley Periodicals, Inc.

Running-based Anaerobic Sprint Test as a Procedure to Evaluate Anaerobic Power.

PubMed

Andrade, V L; Zagatto, A M; Kalva-Filho, C A; Mendes, O C; Gobatto, C A; Campos, E Z; Papoti, M

2015-12-01

The aim of this study was to evaluate the use of the running anaerobic sprint test (RAST) as a predictor of anaerobic capacity, compare it to the maximal accumulated oxygen deficit (MAOD) and to compare the RAST's parameters with the parameters of 30-s all-out tethered running on a treadmill. 39 (17.0±1.4 years) soccer players participated in this study. The participants underwent an incremental test, 10 submaximal efforts [50-95% of velocity correspondent to VO(2MAX) (vVO(2MAX))] and one supramaximal effort at 110% of vVO(2MAX) for the determination of MAOD. Furthermore, the athletes performed the RAST. In the second stage the 30-s all-out tethered running was performed on a treadmill (30-s all-out), and compared with RAST. No significant correlation was observed between MAOD and RAST parameters. However, significant correlations were found between the power of the fifth effort (P5) of RAST with peak and mean power of 30-s all-out (r=0.73 and 0.50; p<0.05, respectively). In conclusion, the parameters from RAST do not have an association with MAOD, suggesting that this method should not be used to evaluate anaerobic capacity. Although the correlations between RAST parameters with 30-s all-out do reinforce the RAST as an evaluation method of anaerobic metabolism, such as anaerobic power. © Georg Thieme Verlag KG Stuttgart · New York.

47 CFR 64.3001 - Obligation to transmit 911 calls.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Obligation to transmit 911 calls. 64.3001 Section 64.3001 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES... Obligation to transmit 911 calls. All telecommunications carriers shall transmit all 911 calls to a PSAP, to...

47 CFR 64.3001 - Obligation to transmit 911 calls.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 3 2012-10-01 2012-10-01 false Obligation to transmit 911 calls. 64.3001 Section 64.3001 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES... Obligation to transmit 911 calls. All telecommunications carriers shall transmit all 911 calls to a PSAP, to...

47 CFR 64.3001 - Obligation to transmit 911 calls.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 3 2013-10-01 2013-10-01 false Obligation to transmit 911 calls. 64.3001 Section 64.3001 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES... Obligation to transmit 911 calls. All telecommunications carriers shall transmit all 911 calls to a PSAP, to...

47 CFR 64.3001 - Obligation to transmit 911 calls.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 3 2014-10-01 2014-10-01 false Obligation to transmit 911 calls. 64.3001 Section 64.3001 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES... Obligation to transmit 911 calls. All telecommunications carriers shall transmit all 911 calls to a PSAP, to...

47 CFR 64.3001 - Obligation to transmit 911 calls.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 3 2011-10-01 2011-10-01 false Obligation to transmit 911 calls. 64.3001 Section 64.3001 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES... Obligation to transmit 911 calls. All telecommunications carriers shall transmit all 911 calls to a PSAP, to...

Formation of glycosidases in batch and continuous culture of Bacteroides fragilis.

PubMed Central

Berg, J O; Nord, C E; Wadström, T

1978-01-01

Nine strains of bacteroides fragilis were cultivated in stirred fermentors and tested for their ability to produce glycosidases. B. fragilis subsp. vulgatus B70 was used for optimizing the production of glycosidases. The highest bacterial yield was obtained in proteose peptone-yeast extract medium. The optimum pH for maximal bacterial yield was 7.0, and the optimum temperature for growth was 37 degrees C. The formation of glycosidases was optimal between pH 6.5 and 7.5, and the optimum temperature for synthesis of glycosidases was between 33 and 37 degrees C. Culture under controlled conditions in fermentors gave more reproducible production of glycosidases than static cultures in bottles. The strain was also grown in continuous culture at a dilution rate of 0.1 liter/h at pH 7.0 and 37 degrees C with a yield of 2.0 mg of dry weight per ml in the complex medium. The formation of glycosidases remained constant during the entire continuous process. PMID:25044

Anaerobic Aryl Reductive Dehalogenation of Halobenzoates by Cell Extracts of “Desulfomonile tiedjei”

PubMed Central

DeWeerd, Kim A.; Suflita, Joseph M.

1990-01-01

We studied the transformation of halogenated benzoates by cell extracts of a dehalogenating anaerobe, “Desulfomonile tiedjei.” We found that cell extracts possessed aryl reductive dehalogenation activity. The activity was heat labile and dependent on the addition of reduced methyl viologen, but not on that of reduced NAD, NADP, flavin mononucleotide, flavin adenine dinucleotide, desulfoviridin, cytochrome c3, or benzyl viologen. Dehalogenation activity in extracts was stimulated by formate, CO, or H2, but not by pyruvate plus coenzyme A or by dithionite. The pH and temperature optima for aryl dehalogenation were 8.2 and 35°C, respectively. The rate of dehalogenation was proportional to the amount of protein in the assay mixture. The substrate specificity of aryl dehalogenation activity for various aromatic compounds in “D. tiedjei” cell extracts was identical to that of whole cells, except differences were observed in the relative rates of halobenzoate transformation. Dehalogenation was 10-fold greater in “D. tiedjei” extracts prepared from cells cultured in the presence of 3-chlorobenzoate, suggesting that the activity was inducible. Aryl reductive dehalogenation in extracts was inhibited by sulfite, sulfide, and thiosulfate, but not sulfate. Experiments with combinations of substrates suggested that cell extracts dehalogenated 3-iodobenzoate more readily than either 3,5-dichlorobenzoate or 3-chlorobenzoate. Dehalogenation activity was found to be membrane associated. This is the first report characterizing aryl dehalogenation activity in cell extracts of an obligate anaerobe. PMID:16348308

Environmental impacts of anaerobic digestion and the use of anaerobic residues as soil amendment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mosey, F.E.

1996-01-01

This paper defines the environmental role of anaerobic digestion within the overall objective of recovering energy from renewable biomass resources. Examples and opportunities for incorporating anaerobic digestion into biomass-to-energy schemes are discussed, together with environmental aspects of anaerobic digestion plants. These include visual, public amenity, pathogens and public health, odor control, and gaseous emissions. Digestate disposal and the benefits of restrictions on recycling organic wastes and biomass residues back to the land are discussed, particularly as they relate to American and European codes of practice and environmental legislation. The paper concludes that anaerobic digestion, if performed in purpose-designed reactors thatmore » efficiently recover and use biogas, is an environmentally benign process that can enhance energy recovery and aid the beneficial land use of plant residues in many biomass-to-energy schemes.« less

Nature, nomenclature and taxonomy of obligate methanol utilizing strains.

PubMed

Cercel, M

1999-01-01

In a screening program, a number of different bacterial strains with the ability to utilize methanol as a sole carbon and energy source were isolated and described. They are well known methanol utilizing genera Pseudomonas, Klebsiella, Micrococcus, Methylomonas or, on the contrary, the new, unknown genera and species of methylotrophic bacteria. In the last category, Acinetobacter and Alcaligenes are the new reported genera of organisms able to use methanol as a sole carbon and energy source. The present paper reports the very complex physiological and biochemical modifications when very versatile bacteria such as Pseudomonas aeruginosa and Acinetobacter calcoaceticus are cultured on methanol and when the obligate methylotrophic state is compared with the facultative methylotrophic state of the same bacterial strain. Based on experiments and comparisons with literature data, it seems that Methylomonas methanica is the obligate methylotrophic state of Pseudomonas aeruginosa and that Acinetobacter calcoaceticus is the facultative methylotrophic state of Methylococcus capsulatus, an obligate methylotroph. The relationship of the obligate to the facultative and of the facultative to the obligate methylotrophy were established. These new methylotrophic genera and species, the profound physiological and biochemical modifications as well as the new data concerning nature, nomenclature and taxonomy of methanol utilizing bateria were reported for the first time in 1983.

Value, obligation and the asymmetry question.

PubMed

Tooley, Michael

1998-04-01

Is there a prima facie obligation to produce additional individuals whose lives would be worth living? In his paper 'Is it good to make happy people?', Stuart Rachels argues not only that there is, but, also, that precisely as much weight should be assigned to the quality of life that would be enjoyed by such potential persons, if they were to be actualized, as to the quality of life enjoyed by actually existing persons. In response, I shall argue, first, that Rachels' view is exposed to very serious objections, and secondly, that his arguments in support of his position involve a crucial assumption, which cannot be sustained, concerning the relation between, on the one hand, propositions about good-making and bad-making properties, and, on the other, propositions about right-making and wrong-making ones. I shall then argue that there is a very plausible position concerning the conditions under which an action can be morally wrong which entails the following asymmetry: there is a prima facie obligation not to bring into existence individuals whose lives are not worth living, but there is no corresponding obligation to create additional individuals whose lives would be worth living.

Inhibition of Anaerobic Biological Treatment: A Review

NASA Astrophysics Data System (ADS)

Hou, Li; Ji, Dandan; Zang, Lihua

2018-01-01

Anaerobic digestion is a method for treating living and industrial wastewater by anaerobic degradation of organic compounds, which can produce biogas (carbon dioxide and methane mixture) and microbial biomass. And biogas as a renewable resource, can replace the use of ore fuel. In the process of anaerobic digestion, the problems of low methane yield and unstable reaction process are often encountered, which limits the widespread use of this technology. Various inhibitors are the main limiting factors for anaerobic digestion. In this paper, the main factors limiting anaerobic digestion are reviewed, and the latest research progress is introduced.

The capability of non-native strains of Bacteroides bacteria to detect bacteriophages as faecal indicators in a tropical area.

PubMed

Sirikanchana, K; Wangkahad, B; Mongkolsuk, S

2014-12-01

To evaluate the use of nonlocal, already-available strains of phages to indicate faecal contamination in Thailand waters. Phages of Bacteroides fragilis strains ATCC 700786 (RYC2056PH) and ATCC 51477 (HSP40PH) were measured in 71 human and animal wastewater samples in Thailand using a double-layer agar assay. Bacteriophage RYC2056PH was detected at concentrations comparable to representative human and animal wastewater samples from European and Mediterranean countries, with 61·7 and 33·3% above the threshold value of 100 PFU 100 ml(-1) in wastewater samples of human and animal origins, respectively. On the other hand, HSP40PH was detected at low concentrations in both human- and animal-polluted wastewaters. Moreover, RYC2056PH was found in 12 canal waters with human-influenced pollution and was not detected in 6 nonpolluted river waters being tested in this study. The presence of RYC2056PH could indicate nonsource-specific faecal contamination in Thailand. This study provided the first evidence that bacteriophages of the European-isolated B. fragilis strain RYC2056 could be used as nonsource-specific faecal indicators in the Southeast Asian region. The results of this study support the worldwide use of Bacteroides phages as faecal indicators. © 2014 The Society for Applied Microbiology.

Intra-Genomic Heterogeneity in 16S rRNA Genes in Strictly Anaerobic Clinical Isolates from Periodontal Abscesses.

PubMed

Chen, Jiazhen; Miao, Xinyu; Xu, Meng; He, Junlin; Xie, Yi; Wu, Xingwen; Chen, Gang; Yu, Liying; Zhang, Wenhong

2015-01-01

Members of the genera Prevotella, Veillonella and Fusobacterium are the predominant culturable obligate anaerobic bacteria isolated from periodontal abscesses. When determining the cumulative number of clinical anaerobic isolates from periodontal abscesses, ambiguous or overlapping signals were frequently encountered in 16S rRNA gene sequencing chromatograms, resulting in ambiguous identifications. With the exception of the genus Veillonella, the high intra-chromosomal heterogeneity of rrs genes has not been reported. The 16S rRNA genes of 138 clinical, strictly anaerobic isolates and one reference strain were directly sequenced, and the chromatograms were carefully examined. Gene cloning was performed for 22 typical isolates with doublet sequencing signals for the 16S rRNA genes, and four copies of the rrs-ITS genes of 9 Prevotella intermedia isolates were separately amplified by PCR, sequenced and compared. Five conserved housekeeping genes, hsp60, recA, dnaJ, gyrB1 and rpoB from 89 clinical isolates of Prevotella were also amplified by PCR and sequenced for identification and phylogenetic analysis along with 18 Prevotella reference strains. Heterogeneity of 16S rRNA genes was apparent in clinical, strictly anaerobic oral bacteria, particularly in the genera Prevotella and Veillonella. One hundred out of 138 anaerobic strains (72%) had intragenomic nucleotide polymorphisms (SNPs) in multiple locations, and 13 strains (9.4%) had intragenomic insertions or deletions in the 16S rRNA gene. In the genera Prevotella and Veillonella, 75% (67/89) and 100% (19/19) of the strains had SNPs in the 16S rRNA gene, respectively. Gene cloning and separate amplifications of four copies of the rrs-ITS genes confirmed that 2 to 4 heterogeneous 16S rRNA copies existed. Sequence alignment of five housekeeping genes revealed that intra-species nucleotide similarities were very high in the genera Prevotella, ranging from 94.3-100%. However, the inter-species similarities were

Intra-Genomic Heterogeneity in 16S rRNA Genes in Strictly Anaerobic Clinical Isolates from Periodontal Abscesses

PubMed Central

Chen, Jiazhen; Miao, Xinyu; Xu, Meng; He, Junlin; Xie, Yi; Wu, Xingwen; Chen, Gang; Yu, Liying; Zhang, Wenhong

2015-01-01

Background Members of the genera Prevotella, Veillonella and Fusobacterium are the predominant culturable obligate anaerobic bacteria isolated from periodontal abscesses. When determining the cumulative number of clinical anaerobic isolates from periodontal abscesses, ambiguous or overlapping signals were frequently encountered in 16S rRNA gene sequencing chromatograms, resulting in ambiguous identifications. With the exception of the genus Veillonella, the high intra-chromosomal heterogeneity of rrs genes has not been reported. Methods The 16S rRNA genes of 138 clinical, strictly anaerobic isolates and one reference strain were directly sequenced, and the chromatograms were carefully examined. Gene cloning was performed for 22 typical isolates with doublet sequencing signals for the 16S rRNA genes, and four copies of the rrs-ITS genes of 9 Prevotella intermedia isolates were separately amplified by PCR, sequenced and compared. Five conserved housekeeping genes, hsp60, recA, dnaJ, gyrB1 and rpoB from 89 clinical isolates of Prevotella were also amplified by PCR and sequenced for identification and phylogenetic analysis along with 18 Prevotella reference strains. Results Heterogeneity of 16S rRNA genes was apparent in clinical, strictly anaerobic oral bacteria, particularly in the genera Prevotella and Veillonella. One hundred out of 138 anaerobic strains (72%) had intragenomic nucleotide polymorphisms (SNPs) in multiple locations, and 13 strains (9.4%) had intragenomic insertions or deletions in the 16S rRNA gene. In the genera Prevotella and Veillonella, 75% (67/89) and 100% (19/19) of the strains had SNPs in the 16S rRNA gene, respectively. Gene cloning and separate amplifications of four copies of the rrs-ITS genes confirmed that 2 to 4 heterogeneous 16S rRNA copies existed. Conclusion Sequence alignment of five housekeeping genes revealed that intra-species nucleotide similarities were very high in the genera Prevotella, ranging from 94.3–100%. However, the

7 CFR 400.168 - Obligations of participating insurance company.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 6 2011-01-01 2011-01-01 false Obligations of participating insurance company. 400... participating insurance company. The Agreement will include the following among the obligations of the Company... insurance policies reinsured. (b) The Company shall make available to all eligible producers in the areas...

7 CFR 400.168 - Obligations of participating insurance company.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Obligations of participating insurance company. 400... participating insurance company. The Agreement will include the following among the obligations of the Company... insurance policies reinsured. (b) The Company shall make available to all eligible producers in the areas...

7 CFR 400.168 - Obligations of participating insurance company.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 6 2012-01-01 2012-01-01 false Obligations of participating insurance company. 400... participating insurance company. The Agreement will include the following among the obligations of the Company... insurance policies reinsured. (b) The Company shall make available to all eligible producers in the areas...

7 CFR 400.168 - Obligations of participating insurance company.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 6 2014-01-01 2014-01-01 false Obligations of participating insurance company. 400... participating insurance company. The Agreement will include the following among the obligations of the Company... insurance policies reinsured. (b) The Company shall make available to all eligible producers in the areas...

7 CFR 400.168 - Obligations of participating insurance company.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 6 2013-01-01 2013-01-01 false Obligations of participating insurance company. 400... participating insurance company. The Agreement will include the following among the obligations of the Company... insurance policies reinsured. (b) The Company shall make available to all eligible producers in the areas...

15 CFR 711.4 - Assistance in determining your obligations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Assistance in determining your obligations. 711.4 Section 711.4 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade... ELECTRONIC FILING OF DECLARATIONS AND REPORTS § 711.4 Assistance in determining your obligations. (a...

18 CFR 367.22 - Accounting for asset retirement obligations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Accounting for asset... GAS ACT General Instructions § 367.22 Accounting for asset retirement obligations. (a) An asset... measurement changes to the initial liability for the legal obligation recorded in account 230, Asset...

48 CFR 252.239-7013 - Obligation of the Government.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Government. 252.239-7013 Section 252.239-7013 Federal Acquisition Regulations System DEFENSE ACQUISITION... of Provisions And Clauses 252.239-7013 Obligation of the Government. As prescribed in 239.7411(c), use the following clause: Obligation of the Government (JUL 2006) (a) This basic agreement is not a...

48 CFR 252.239-7013 - Obligation of the Government.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Government. 252.239-7013 Section 252.239-7013 Federal Acquisition Regulations System DEFENSE ACQUISITION... of Provisions And Clauses 252.239-7013 Obligation of the Government. As prescribed in 239.7411(c), use the following clause: Obligation of the Government (JUL 2006) (a) This basic agreement is not a...

18 CFR 292.313 - Reinstatement of obligation to sell.