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Anaerobe

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ISSN (Print) 1075-9964 - ISSN (Online) 1095-8274
Published by Elsevier

[2556 journals]

Validation of a real-time PCR based method for detection of Clostridium botulinum types C, D and their mosaic variants C-D and D-C in a multicenter collaborative trial
- Abstract: Publication date: Available online 10 May 2013
  Source:Anaerobe
  Author(s): Cedric Woudstra , Hanna Skarin , Fabrizio Anniballi , Bruna Auricchio , Dario De Medici , Luca Bano , Ilenia Drigo , Trine Hansen , Charlotta Löfström , Raditijo Hamidjaja , Bart J. van Rotterdam , Miriam Koene , Marie-Hélène Bäyon-Auboyer , Jean-Philippe Buffereau , Patrick Fach
  Two real-time PCR arrays based on the GeneDisc® cycler platform (Pall-GeneDisc Technologies) were evaluated in a multicenter collaborative trial for their capacity to specifically detect and discriminate Clostridium botulinum types C, D and their mosaic variants C-D and D-C that are associated with avian and mammalian botulism. The GeneDisc® arrays developed as part of the DG Home funded European project ‘AnibioThreat’ were highly sensitive and specific when tested on pure isolates and naturally contaminated samples (mostly clinical specimen from avian origin). Results of the multicenter collaborative trial involving eight laboratories in five European Countries (two laboratories in France, Italy and The Netherlands, one laboratory in Denmark and Sweden), using DNA extracts issued from 33 pure isolates and 48 naturally contaminated samples associated with animal botulism cases, demonstrated the robustness of these tests. Results showed a concordance among the eight laboratories of 99.4% to 100% for both arrays. The reproducibility of the tests was high with a relative standard deviation ranging from 1.1% to 7.1%. Considering the high level of agreement achieved between the laboratories these PCR arrays constitute robust and suitable tools for rapid detection of C. botulinum types C, D and mosaic types C-D and D-C. These are the first tests for C. botulinum C and D that have been evaluated in a European multicenter collaborative trial.
  
  PubDate: 2013-05-13T02:03:26Z
Identification of Veillonella tobetsuensis in Tongue Biofilm by Using a Species-Specific Primer Pair
- Abstract: Publication date: Available online 7 May 2013
  Source:Anaerobe
  Author(s): Izumi Mashima , Futoshi Nakazawa
  Veillonella atypica, V. denticariosi, V. dispar, V. parvula, and V. rogosae have been reported to be isolated from human oral cavities. The recently detected V. tobetsuensis in human tongue biofilms was proposed as a novel Veillonella sp. In this study, to determine the distribution and frequency of V. tobetsuensis, we established a method for the detection and identification of V. tobetsuensis by using polymerase chain reaction (PCR) using a species-specific primer pair. The primer pair for V. tobetsuensis was designed on the basis of the nucleotide sequence of the 70-kDa heat shock protein (dnaK) gene of V. tobetsuensis JCM 17976T (=ATCC BAA-2400T). The primer pair generated a specific PCR product for V. tobetsuensis but not for other oral Veillonella spp. With the PCR procedure using the primer pair, we could detect less than 10 ng of genomic DNA extracted from V. tobetsuensis. Thus, the PCR method using this primer pair is suitable for the specific detection and identification of V. tobetsuensis. The distribution and frequency of V. tobetsuensis were investigated by PCR using this species-specific primer pair. V. tobetsuensis was detected in 5 of 27 subjects. V. tobetsuensis was recovered from 19% (5/27) of subjects with other Veillonella species. And, prevalence of V. tobetsuensis ranged from 7.6% to 20.0% in these subjects. V. tobetsuensis is likely to coexist with other Veillonella spp. in tongue biofilm. In this study, the species-specific PCR primer pair for V. tobetsuensis was designed using partial sequences of the dnaK gene. This is the first report using a species-specific primer pair for PCR to determine the distribution and frequency of V. tobetsuensis in tongue biofilm.
  
  PubDate: 2013-05-09T02:03:36Z
Severe Narrowing of Left Cavernous Carotid Artery Associated with Fusobacterium necrophorum Infection Severe Narrowing of Left Carotid with F. necrophorum
- Abstract: Publication date: Available online 7 May 2013
  Source:Anaerobe
  Author(s): Guenet H. DeGaffe , James R. Murphy , Ian J. Butler , Julia Shelburne , Gloria P. Heresi
  Severe oropharyngeal infection can result in Lemierre’s disease, a syndrome with high mortality secondary to inflammation and thrombosis of cervical and intracranial veins with involvement of contiguous structures; however arterial involvement is rare. We report a case of Lemierre’s disease in a 12 year old boy with severe narrowing of the left cavernous carotid artery.
  
  PubDate: 2013-05-09T02:03:36Z
Water dispersible magnetite nanoparticles influence the efficacy of antibiotics against planktonic and biofilm embedded Enterococcus faecalis cells
- Abstract: Publication date: Available online 7 May 2013
  Source:Anaerobe
  Author(s): Mariana Carmen Chifiriuc , Alexandru Mihai Grumezescu , Ecaterina Andronescu , Anton Ficai , Ani Ioana Cotar , Valentina Grumezescu , Eugenia Bezirtzoglou , Veronica Lazar , Radu Radulescu
  The objective of this study was to investigate the potential of magnetic nanoparticles to potentiate, but also to accomplish a sustained and controlled drug release and subsequently improve the efficacy of antibiotics against Enterococcus faecalis, one of the most resistant opportunistic pathogens, that poses a threat to chronically infected or immunocompromised patients and is difficult to eradicate from medical devices. To our knowledge, this is the first study trying to investigate the ability of magnetite nanoparticles to improve the anti-bacterial activity of the current antibiotics against planktonic and biofilm growing E. faecalis. Our results are suggesting that the magnetite nanoparticles may be considered an effective aminoglycoside antibiotics carrier, but a complete understanding of the way in which they selectively interact with different antibiotics and with the bacterial cell is needed, in order to obtain improved strategies for elimination of E. faecalis biofilms on biomedical devices or human tissues.
  
  PubDate: 2013-05-09T02:03:36Z
Transposon mutagenesis of Bacteroides fragilis using a Mariner transposon vector
- Abstract: Publication date: Available online 7 May 2013
  Source:Anaerobe
  Author(s): Yaligara Veeranagouda , Fasahath Husain , Hannah M. Wexler
  The mariner transposon vector pYV07 was tested for use in the mutagenesis of Bacteroides fragilis 638R. The transposon vector efficiently generated mutants in B. fragilis 638R. The transposon disrupted genes were scattered throughout the genome of B. fragilis 638R. This method serves as a powerful tool to study B. fragilis.
  
  PubDate: 2013-05-09T02:03:36Z
Oxygen deprivation affects the antimicrobial action of LL-37 as determined by microplate real-time kinetic measurements under anaerobic conditions
- Abstract: Publication date: Available online 8 May 2013
  Source:Anaerobe
  Author(s): Amir Eini , Asaf Sol , Shunit Coppenhagen-Glazer , Yaniv Skvirsky , Avi Zini , Gilad Bachrach
  Some agents, including Escherichia coli and group A Streptococcus pyogenes cause infections in oxygen depleted sites. LL-37 is a human host defence peptide shown previously to play an important role in controlling infections caused by these bacteria. However, the effect of oxygen levels on the antimicrobial activity of LL-37 remains obscure. In order to test the effect of oxygen (or lack thereof) on LL-37’s activity against E. coli and S. pyogenes, a method for adapting commonly used microtiter plates for real-time growth-kinetic (and growth-inhibition) measurements under anaerobic conditions was developed. Using the proposed method, anaerobic conditions were attained in the microplate within 30 minutes and were maintained for at least five days. Anaerobiosis was further confirmed by comparing the growth of two anaerobic oral species (Porphyromonas gingivalis and Fusobacterium nucleatum) in anaerobic compartments of microtiter plates versus aerobic ones. Both species grew only in the anaerobic compartments of the plates as indicated by the growth curves generated. The sensitivities of E. coli and S. pyogenes to LL-37 were tested under anaerobic conditions and compared to those in aerobic ones. The oxygen facultative E. coli grew to a higher density under aerobic conditions and its sensitivity to LL-37 was increased under anaerobiosis. The microaerophilic pathogen S. pyogenes grew faster and to a higher density under anaerobic conditions and was much more resistant to LL-37 under oxygen deprivation. Our results suggest that resistance to antimicrobial agents of microbes infecting anaerobic-microaerophilic sites should be tested under oxygen-restricted conditions.
  
  PubDate: 2013-05-09T02:03:36Z
Editorial board
- Abstract: Publication date: June 2013
  Source:Anaerobe, Volume 21
  
  PubDate: 2013-05-05T02:04:44Z
Effect of hospital disinfectants on spores of clinical Brazilian Clostridium difficile strains
- Abstract: Publication date: Available online 2 May 2013
  Source:Anaerobe
  Author(s): Thaís Gonçalves Ferreira , Thaís Flecher Barbosa , Felipe Lopes Teixeira , Eliane de Oliveira Ferreira , Rafael Silva Duarte , Regina Maria Cavalcanti Pilotto Domingues , Geraldo Renato de Paula
  The aim of this study was to evaluate the sporicidal activity of hospital disinfectants against spores of two Brazilian C. difficile ribotypes and the BI/NAP1/027. Our results showed that CloroRio® and Cidex Opa® were the most efficient agents for eliminating spores of Clostridium difficile.
  
  PubDate: 2013-05-05T02:04:44Z
Improving the identification of anaerobes in the clinical microbiology laboratory through MALDI-TOF mass spectrometry
- Abstract: Publication date: Available online 29 April 2013
  Source:Anaerobe
  Author(s): Melody Barreau , Isabelle Pagnier , Bernard La Scola
  In this study, 1,325 anaerobes were analyzed by MALDI-TOF MS. Of these, 92.5% were correctly identified at the species level. One unidentified species and several uncommon and rare species were identified. These results show that this technique has become the new gold standard for the routine identification of clinical anaerobes.
  
  PubDate: 2013-05-01T02:06:19Z
Effect of age, dose and antibiotic therapy on the development of Clostridium difficile infection in neonatal piglets
- Abstract: Publication date: Available online 24 April 2013
  Source:Anaerobe
  Author(s): Paulo H.E. Arruda , Darin M. Madson , Alejandro Ramirez , Eric Rowe , Joshua T. Lizer , J. Glenn Songer
  Piglet diarrhea is associated with increased pre-weaning mortality, poor growth rates, and variation in weight at weaning. Clostridium difficile is a known cause of enteric disease in neonatal piglets, yet risk factors associated with C. difficile infection in piglets are unknown. The objectives of this study were (1) to evaluate the consistency and severity of lesions in piglets challenged with C. difficile at different bacterial doses (DOSAGE experiment), (2) evaluate the use of antibiotics as a contributing risk factor in 1-day-old piglets (ANTIMICROBIAL experiment), and (3) to provide a clinical and histological evaluation of C. difficile infection in 10-day-old piglets (AGE experiment). One hundred and eleven conventional neonatal pigs were snatch farrowed and divided into experimental groups addressing the objectives. In the DOSAGE experiment, 40 1-day-old piglets were sham inoculated or challenged with varying amounts of C. difficile heat shocked spores and euthanized 72 h post infection. Results indicate a clear trend for disease development as bacterial numbers increase. In the ANTIMICROBIAL experiment, 39 1-day-old piglets were challenged and then treated with one of four different antibiotics after 16 h. No significant difference in disease development was found. Thirty-three 10-day-old piglets were given varying doses of C. difficile in the AGE experiment. Disease and lesions were reproduced in 10 day-old piglets. Combined results indicate that C. difficile dosage appears to be an important factor that influences the appearance and severity of lesions, 10 day-old pigs can develop disease associated with Clostridium difficile, and antibiotic administration following inoculation may not be a major contributor for disease in neonatal piglets.
  
  PubDate: 2013-04-27T03:31:19Z
In vitro probiotic properties of Lactobacillus fermentum SK5 isolated from vagina of a healthy woman
- Abstract: Publication date: Available online 24 April 2013
  Source:Anaerobe
  Author(s): Sanae Kaewnopparat , Nattakan Dangmanee , Nattha Kaewnopparat , Teerapol Srichana , Malyn Chulasiri , Sukanya Settharaksa
  A lactobacillus strain isolated from a vaginal tract of a healthy woman was examined in vitro for its probiotic potential. This strain, identified as Lactobacillus fermentum SK5, was able to survive at pH 3-4 and 0.1-0.2% bile, and unaffected by pepsin (3 g l-1) and pancreatin (1 g l-1), but was susceptible to all tested antibiotics except metronidazole. L. fermentum SK5 had an antimicrobial potential against gastrointestinal pathogenic Escherichia coli and vaginal pathogenic Gardnerella vaginalis. The effective substance was suspected to be a bacteriocin-like compound with a molecular weight of more than 10 kDa, but hydrogen peroxide was also detected. Further studies revealed that L. fermentum SK5 had good autoaggregation characteristic and a high surface hydrophobicity that enhanced its adhesion ability to epithelial cells and for biofilm formation. This lactobacillus showed coaggregation with E. coli and G. vaginalis to affect their adhesion and colonization. The adhesion of L. fermentum SK5 to HeLa, HT-29 and Caco-2 cells and its inhibition of E. coli and G. vaginalis adherence to these cells were demonstrated. These incidences provided evidence of the possible colonization of L. fermentum SK5 that would prevent binding and growth of E. coli and G. vaginalis onto intestinal and vaginal epithelial cells. On the basis of the ability of L. fermentum SK5 to inhibit pathogenic microorganisms through coaggregation and antimicrobial substances, it is likely that this lactobacillus strain could be a potential probiotic candidate for beneficial use in protecting against gastrointestinal and vaginal microbial infections.
  
  PubDate: 2013-04-27T03:31:19Z
Proteomic changes in Bacteroides fragilis exposed to subinhibitory concentration of piperacillin/tazobactam
- Abstract: Publication date: Available online 23 April 2013
  Source:Anaerobe
  Author(s): Luciano de Castro Veloso , Kênia Valéria dos Santos , Hélida Monteiro de Andrade , Simone da Fonseca Pires , Simone Gonçalves dos Santos , Mariana Jesus Vaz Trindade , Luiz de Macêdo de Farias , Maria Auxiliadora Roque de Carvalho
  Bacteroides fragilis is the anaerobe most frequently isolated from clinical specimens and piperacillin/tazobactam is among the drugs that can be used to treat polymicrobial infections in which this bacteria is often involved. During antibiotic therapy, inhibitory concentrations of antibiotics are always followed by subinhibitory concentrations which can generate phenotypic changes in bacteria. So, in this study we aimed to evaluate changes in the proteomic profile of B. fragilis grown in a sub-MIC of PTZ, using 2-D electrophoresis followed by matrix-assisted laser desorption/ionization time-of-flight/time of-flight. Analysis of the 2-DE gels showed 18 spots with significantly different volume percentages between experimental conditions and 12 were successfully identified by MS/MS. Two proteins with decreased abundance in sub-MIC condition were involved in the glycolysis (glyceraldehyde-3-phosphate dehydrogenase and triose phosphate isomerase), others two involved in amino acid metabolism (Oxoacyl-(acyl-carrier protein) synthase II and dihydrodipicolinate reductase), and finally, one protein involved in fatty acid metabolism (UDP-N-acetylglucosamine acyltransferase). Among the proteins with increased abundance, we founded three ATP synthase (alpha, beta, and alpha type V), which could be involved in antibiotic bacterial resistance by efflux pump, one protein involved in glycolysis (enolase), and one involved in protein degradation (aminoacyl-histidine dipeptidase). In conclusion, our data show overall changes in the proteome of B. fragilis conducted by sub-MIC of PTZ, whose consequences on bacterial physiology deserve further investigation.
  
  PubDate: 2013-04-27T03:31:19Z
The relationship between phenotype, ribotype, and clinical disease in human Clostridium difficile isolates
- Abstract: Publication date: Available online 20 April 2013
  Source:Anaerobe
  Author(s): Paul E. Carlson Jr. , Seth T. Walk , Alexandra E.T. Bourgis , Melissa W. Liu , Fatos Kopliku , Eugene Lo , Vincent B. Young , David M. Aronoff , Philip C. Hanna
  Since 2000, C. difficile isolates of ribotype 027 have been linked to outbreaks in North America and Europe and also an increased rate of colectomy and death among infected individuals. It has been proposed that enhanced sporulation and toxin production were associated with this apparent increase in virulence of 027 isolates. Since only a limited number of isolates have been examined, the relationship of these phenotypes to a specific ribotype, and as well as to clinical disease severity, remains controversial. 106 recent clinical isolates from the University of Michigan Health System were characterized for the ability to sporulate, produce viable spores, grow in rich media, and produce toxins in vitro. Significant variation was observed between isolates for each of these phenotypes. Isolates of ribotype 027 produced higher levels of toxin and exhibited slower growth compared to other ribotypes. Importantly, increased spore production did appear to be relevant to severe C. difficile infection, as determined by available clinical meta-data. These data provide the first significant difference between isolates from severe vs. less severe disease based on an in vitro C. difficile phenotype and suggest that clinical outcome is better predicted by bacterial attributes other than ribotype.
  
  PubDate: 2013-04-23T03:33:07Z
Diagnostic accuracy of a multiplex real-time PCR to predict Clostridium difficile ribotype 027
- Abstract: Publication date: Available online 16 April 2013
  Source:Anaerobe
  Author(s): Jonathan Barra-Carrasco , Cristian Hernández-Rocha , Camila Miranda-Cárdenas , Manuel Álvarez-Lobos , Ana María Guzmán Durán , Daniel Paredes-Sabja
  
  PubDate: 2013-04-19T03:30:52Z
Tolerance of Bifidobacterium human isolates to bile, acid and oxygen
- Abstract: Publication date: Available online 15 April 2013
  Source:Anaerobe
  Author(s): Valérie Andriantsoanirina , Solène Allano , Marie José Butel , Julio Aires
  Bifidobacteria are part of the human gastrointestinal microbiota and are used as probiotics in functional food products because of their health promoting properties. However, only few data are available on the phenotypic characteristics displayed by human bifidobacteria strain populations. In this study we compared the in vitro tolerance to acid, bile and oxygen of the largest number of independent human intestinal strains. Bile and acid tolerance varied among species and independent strains within a species: B. adolescentis strains were the most tolerant to bile followed by B. longum and B. breve; B. longum, B. breve and B. dentium showed the highest viability levels after exposure to acid pH. Oxygen tolerance was largely distributed among intestinal bifidobacteria: B. longum, B. breve and B. bifidum showed the highest oxygen tolerance. B. adolescentis showed the highest susceptibility to acid and oxygen stresses. The present study gave us the opportunity to update our knowledge about the phenotypic characteristics of human intestinal bifidobacteria. B. longum and B. breve harboured the best tolerance to oxygen, bile and acid stresses. Based on such biological characters, B. longum and B. breve species showed the highest interest in terms of potential selection of human probiotics.
  
  PubDate: 2013-04-19T03:30:52Z
The Microbiota and Inflammatory Bowel Disease: Insights from Animal Models
- Abstract: Publication date: Available online 17 April 2013
  Source:Anaerobe
  Author(s): Joanna M. Peloquin , Deanna D. Nguyen
  Inflammatory bowel disease (IBD) is thought to result from a dysregulated immune response to intestinal microbial flora in individuals with genetic predisposition(s). Genome wide association studies (GWAS) in human IBD have identified more than 150 associated loci, some of which are key players in innate immunity and bacterial handling, reflecting the importance of the microbiota in disease pathogenesis. In fact, the presence of a microbial flora is not only crucial to the development of a normal murine immune system but also critical for the development of disease in the majority of animal models of IBD. Although animal models do not perfectly recapitulate human IBD, they have led to the discovery of important concepts in IBD pathogenesis, such as the central role of microbiota in disease development and perpetuation. Many genetically susceptible models do not develop colitis when raised in a germ-free or Helicobacter-free environment. In fact, disease in most models can be attenuated or completely abolished with antibiotic treatment. Moreover, an interplay between intestinal microbiota and mucosal immune activation is suggested by the presence of serum antibodies against the Cbir1 flagellin, an immunodominant antigen that activates TLR5, in certain models of spontaneous colitis as well as in human patients. Furthermore, T cells reactive to Cbir1 are able to induce disease in recipient mice upon adoptive cell transfer, demonstrating the pro-inflammatory properties of certain bacterial products. In fact, it has been shown that transfer of certain intestinal bacteria from a specific genetically altered mouse model with spontaneous colitis can induce disease in wild-type mice upon co-housing or direct feeding. These observations demonstrate the pathogenic potential of intestinal microbiota in IBD. However, intestinal bacteria are not always maladaptive in mucosal homeostasis. Both Bacteroides fragilis and Clostridium species promote the number and function of a certain regulatory T cell subset in the colon leading to protection against murine colitis. In fact, normal development of regulatory cells and epithelial cell integrity are abolished in the absence of an intestinal flora, suggestive of the need for certain microbial components to induce beneficial anti-inflammatory mechanisms. All in all, altered immune responses to microbes play a crucial role in IBD pathogenesis. However, certain components of the microbiota are also likely critical for normal development of regulatory mechanisms that contribute to mucosal homeostasis. Findings in animal models highlight the concept that IBD is a disease that results from the interplay of genetics and microbial/environmental factors.
  
  PubDate: 2013-04-19T03:30:52Z
What is hot in the anaerobe literature? Clostridium difficile infections
- Abstract: Publication date: Available online 12 April 2013
  Source:Anaerobe
  Author(s): Carl Erik Nord
  
  PubDate: 2013-04-15T02:07:17Z
Presence of Clostridium perfringens in retail chicken livers
- Abstract: Publication date: Available online 9 April 2013
  Source:Anaerobe
  
  Chicken livers sold at grocery stores in Tucson, AZ, USA were examined for the presence of Clostridium perfringens. Results showed that 69.6% of sampled retail chicken livers were culture positive for C. perfringens. Genotyping of the isolates showed that all the isolates were type A, but were negative for the enterotoxin gene (cpe).
  
  PubDate: 2013-04-11T03:32:19Z
Antimicrobial activity of ethanol extracts of Laminaria japonica against oral microorganisms
- Abstract: Publication date: Available online 9 April 2013
  Source:Anaerobe
  
  Laminaria japonica is a brown alga, which is consumed widely in Korea, Japan, and China. This study investigated the antimicrobial activity of ethanol extracts of L. japonica against oral microbial species to assess the possible application of L. japonica extracts in dental care products. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined in culture medium using a microdilution method. The MICs of ethanol extracts of L. japonica with oral streptococci were 62.5–500 μg/ml and the MBCs were 125–1,000 μg/ml. The MICs of Actinomyces naeslundii and Actinomyces odontolyticus were 250 and 62.5 μg/ml, respectively. The MBCs of A. naeslundii and A. odontolyticus were 500 and 250 μg/ml, respectively. The MICs were 250 and 62.5 μg/ml for Fusobacterium nucleatum and Porphyromonas gingivalis, respectively. The killing of Streptococcus mutans and P. gingivalis were dependent on the incubation time. The killing of S. mutans, A. odontolyticus, and P. gingivalis was significantly dependent on the extract concentration. Bacterial treatment with L. japonica extracts changed the cell surface texture of S. mutans, A. odontolyticus, and P. gingivalis. The results of this study suggest that L. japonica extracts may be useful for the development of antimicrobial agents to combat oral pathogens.
  
  PubDate: 2013-04-11T03:32:19Z
The effects of liquid versus spray-dried Laminaria digitata extract on selected bacterial groups in the piglet gastrointestinal tract (GIT) microbiota
- Abstract: Available online 29 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  In this study, the effects of supplementing animal feed with a liquid and spray-dried fucoidan and laminarin extract, derived from the seaweed Laminaria digitata on the porcine gastrointestinal microbiota, specifically the communities of Lactobacillus, Bifidobacterium and enterobacteria were evaluated. Twenty four piglets were fed one of three diets over a 21-day period to determine the effect that each had on the bacterial communities. The dietary treatments were as follows; (1) control diet, (2) control diet plus spray dried formulation of laminarin fucoidan (L/F-SD) extract, (3) control diet plus a liquid formulation of (L/F-WS) extract. Control diet consisted of wheat, soya bean meal, soya oil and a vitamin and mineral mixture. The L/F-SD and L/F-WS supplemented diets had equal proportion of 500 ppm laminarin and fucoidan. At the end of the 21 day feeding period all animals were sacrificed and samples were collected from the ileum, caecum and colon. Counts were determined for Lactobacillus, Bifidobacterium and enterobacteria. Plate count analysis revealed that the L/F-SD diet caused a statistically significant 1.5 log and 2 log increases in the Lactobacillus and Bifidobacterium counts of ileum samples respectively. A greater difference was observed with the L/F-WS diet in that Lactobacillus and Bifidobacterium increased by 2 log and 3 log respectively. Alterations in the Lactobacillus species composition of the gastrointestinal tract (GIT) were analysed using specific PCR - denaturing gradient gel electrophoresis (PCR-DGGE). The DGGE profiles indicated that Lactobacillus species richness decreased along the gastrointestinal tract i.e. the number of dominant species detected in the colon was less than those detected in the ileum and caecum irrespective of the diet consumed. Consumption of both the L/F-SD and L/F-WS diets resulted in a richer Lactobacillus species composition in the ileum, with the L/F-SD diet being associated the emergence of Lactobacillus agilis in the colon. The study indicated that the L/F-WS extract was superior to the L/F-SD extract in increasing the titre of beneficial bacteria in the gastrointestinal tract (GIT).
  
  PubDate: 2013-03-31T06:15:48Z
Non specificity of primers used for PCR based serogrouping of Dichelobacter nodosus and identification of a novel Dichelobacter nodosus strain
- Abstract: Available online 29 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  The present study records the first case of non specificity of typing primers developed by Dhungyel et al. [1]. A strain of D. nodosus (JKS-20G) isolated from ovine footrot in Kashmir, India, showed specificity for serogroup C and G primers. The fimA sequence of the strain turned out to be closer to serogroup G than C. The nucleotide sequence showed maximum homology of 92% with that of serotype G1 strain 238 and 95% with partial sequence available for serotype G2 strain VCS1004. However, the deduced amino acid sequence of the fimbrial subunit gene of JKS-20G differed from strain 238 by 16 amino acids and by four amino acids from that of partial sequence of strain VCS1004. This variation indicates towards declaring this isolate as new serotype (G3) but just insufficient to classify this into a new serogroup. Some of the amino acid substitutions were located within three hypervariable regions a characteristic of different serogroups. However, to ascertain whether this isolate deserve new serotype status, there is a need to go for antigenic characterization of this isolate using the tube and cross tube agglutination test.
  
  PubDate: 2013-03-31T06:15:48Z
Protective effect of a mixture of kefir-isolated lactic acid bacteria and yeasts in a hamster model of Clostridium difficile infection
- Abstract: Available online 29 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  The objective of this work was to test the protective effect of a mixture (MM) constituted by kefir-isolated microorganisms (L. plantarum, L. kefir, Lc. lactis, K. marxianus and S. cerevisiae) in a hamster model of infection with C. difficile, an anaerobic Gram-positive bacterium that causes diarrhoea. Placebo or MM was administered ad libitum in drinking water from day 0 to the end of treatment. Hamsters received orally 200 μg of clyndamicin at day 7 and then were infected with 1x108 CFU of C. difficile by gavage. Development of diarrhoea and death were registered until the end of the protocol. Surviving animals were sacrificed at day 16, and a test for biological activity of clostridial toxins and histological stainings were performed in caecum samples. Six of seven infected animals developed diarrhoea and 5/7 died at the end of the experimental protocol. The histological sections showed edema and inflammatory infiltrates with neutrophils and crypt abscesses. In the group of animals infected and treated with MM1/1000, only 1 of 7 hamsters showed diarrhoea and none of them died. The histological sections showed only a slight thickening of the mucosa with presence of lymphocytic infiltrate. These results demonstrate that an oral treatment with a mixture of kefir-isolated bacteria and yeasts was able to prevent diarrhoea and enterocolitis triggered by C. difficile.
  
  PubDate: 2013-03-31T06:15:48Z
Enterotoxigenic Bacteroides fragilis cause lethal colitis in Mongolian gerbils
- Abstract: Available online 26 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  Enterotoxigenic Bacteroides fragilis (ETBF) causes inflammatory diarrhea in humans and livestock and is implicated in colorectal cancer. In this report, we show for the first time that ETBF can induce profuse diarrhea and an acute, lethal colitis in Mongolian gerbils.
  
  PubDate: 2013-03-27T22:37:20Z
Microbial Community Analysis of Swine Wastewater Anaerobic Lagoons by Next Generation DNA Sequencing
- Abstract: Available online 26 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  Anaerobic lagoons are a standard practice for the treatment of swine wastewater. This practice relies heavily on microbiological processes to reduce concentrated organic material and nutrients. Despite this reliance on microbiological processes, research has only recently begun to identify and enumerate the myriad and complex interactions that occur in this microbial ecosystem. To further this line of study, we utilized a next-generation sequencing (NGS) technology to gain a deeper insight into the microbial communities along the water column of four anaerobic swine wastewater lagoons. Analysis of roughly one million 16S rDNA sequences revealed a predominance of operational taxonomic units (OTUs) classified as belonging to the phyla Firmicutes (54.1%) and Proteobacteria (15.8%). At the family level, 33 bacterial families were found in all twelve lagoon sites and accounted for between 30 - 50% of each lagoon’s OTUs. Analysis by nonmetric multidimensional scaling (NMS) revealed that TKN, COD, ORP, TSS, and DO were the major environmental variables in affecting microbial community structure. Overall, 839 individual genera were classified, with 223 found in all four lagoons. An additional 321 genera were identified in sole lagoons. The top 25 genera accounted for approximately 20% of the OTUs identified in the study, and the low abundances of most of the genera suggests that most OTUs are present at low levels. Overall, these results demonstrate that anaerobic lagoons have distinct microbial communities which are strongly controlled by the environmental conditions present in each individual lagoon.
  
  PubDate: 2013-03-27T22:37:20Z
Editorial board
- Abstract: April 2013
  Publication year: 2013
  Source:Anaerobe, Volume 20
  
  PubDate: 2013-03-27T22:37:20Z
Scarce detection of mobile erm genes associated with tetQ in Bacteroides and Parabacteroides from Costa Rica
- Abstract: Available online 22 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  The frequency of finding of clindamycin-resistant anaerobic bacteria in clinical samples has doubled from 2008 to 2010 in Costa Rica. To determine whether this increase is due to dissemination of erm genes aided by tetQ elements, we analyzed 100 isolates of Bacteroides or Parabacteroides from a regional hospital, a national hospital, and the community. Antimicrobial susceptibilities were recorded with a broth micro-dilution method and erm genes were detected by PCR and Southern blotting. In addition, plasmid isolation and mating experiments were performed to clarify the location and mobility of the detected erm genes. Resistance to clindamycin was by far more frequent in the regional hospital (72%) than in the national hospital (29%) and the community (26%). Resistance to tetracycline was even more common, with the community (85%) outweighing the hospitals (71-72%). While MIC of clindamycin were higher in the hospitals than in the community (P < 0.05), the opposite was seen for tetracycline (P < 0.0001). Of the sought-after genes, only ermG (n=2), ermA (n=1), and ermF (n=1) were detected in the hospitals and ermF in the community (n=2). In opposition to the low frequency of finding of erm genes, 71% of the isolates were positive for tetQ. None of the detected genes were encoded on plasmids. Only three isolates from the hospitals transferred their erm genes laterally. By contrast, 13 hospital isolates and two community isolates transferred tetQ. Despite the widespread finding of tetracycline-resistant tetQ-positive bacteria, mobile erm genes were rare in our bacterial collection. We conclude that the detected erm genes are likely not included in typical conjugative transposons of Bacteroides and Parabacteroides.
  
  PubDate: 2013-03-24T22:28:59Z
Evaluation of adhesion properties and antibacterial activities of the infant gut commensal Bifidobacterium bifidum PRL2010
- Abstract: Available online 22 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  Bifidobacteria are extensively exploited by the food industry as health-promoting microorganisms. However, very little is known about the molecular mechanisms responsible for these beneficial activities, or the molecular players that sustain their ability to colonize and persist within the human gut. Here, we have investigated the enteric adaptation features of the gut commensal Bifidobacterium bifidum PRL2010, originally isolated from infant feces. This strain was able to survive under gastrointestinal challenges, while it was shown to adhere to human epithelial intestinal cell monolayers (Caco 2 and HT-29), thereby inhibiting adhesion of pathogenic bacteria such as Escherichia coli and Cronobacter sakazakii.
  
  PubDate: 2013-03-24T22:28:59Z
Study of probiotic potential of four wild Lactobacillus rhamnosus Strains
- Abstract: Available online 22 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  The four wild Lactobacillus rhamnosus strains were examined in vitro for resistance to simulated gastro and intestinal juices, adhesion to HT-29 cells, antagonistic activity against enteric pathogens and immunomodulating activity. The strains L. rhamnosus SB5L, J5L and IN1L were able to survive in simulated gastro juice while the strain L. rhamnosus SB31L lost viability exposed to simulated gastro juice for 3 h. The four strains had high viability in simulated small intestinal juice with little loss (<1.0 cycle reduction). The strains SB5L, J5L and IN1L antagonized against Escherichia coli ATCC 25922, Salmonella enterica serovar Typhimurium ATCC 14028, Shigella sonnei ATCC 25931. The strain L. rhamnosus IN1L had the highest adhesive capability to HT-29 cells in vitro (251 bacteria cells per 100 HT-29 cells) compared to the other three L. rhamnosus strains. The live bacteria, cell wall and DNA of the four L. rhamnosus induced the secretion of pro-inflammatory cytokines IL-12 (p70), IFN-γ and TNF-α by human peripheral blood mononuclear cells (PBMCs). The levels of IL-12 (p70), IFN-γ and TNF-α produced by stimulated PBMCs were significantly higher (P<0.05) than those of the control. Those data indicated that the four L. rhamnosus strains have the potential as the probiotic for human being use, although further studies are still needed.
  
  PubDate: 2013-03-24T22:28:59Z
Counterpoint: Is Clostridium difficile a Food-borne Disease'
- Abstract: Available online 22 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  The increase in community associated Clostridium difficile disease paired with recent data on C. difficile in retail foods has led to speculation that C. difficile is a food-borne pathogen. However, there is no current epidemiologic evidence (i.e. restaurant or food-associated outbreaks) to support this hypothesis. Rates of C. difficile recovery from food vary widely across laboratories and may be due to a number of confounding factors. This commentary discusses the results of two published investigations and suggests that higher prevalence rates observed in some food studies may be due to laboratory contamination. The conclusions are that prevalence of C. difficile in retail foods is relatively low and further investigations are required to determine if C. difficile is food-borne.
  
  PubDate: 2013-03-24T22:28:59Z
The prevalence of antibiotic resistance genes in Bacteroides fragilis group strains isolated in different European countries
- Abstract: Available online 14 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  From the 2008-2009 European Bacteroides antibiotic resistance survey, we selected 161 strains for detection of antibiotic resistance genes (cepA, cfxA, cfiA, nim, ermB, ermF, ermG, linA, mefA, msrSA, tetM, tetQ, tetX, tetX1, tet36 and bexA). To facilitate the throughput, the genes were detected by Real-Time PCR. The presence of the genes was correlated with the known MIC data of the strains for the appropriate antibiotics. For the β-lactams, the cepA gene was found in 70.8 % of the tested strains (all resistant to ampicillin), but its presence did not correlate with the ampicillin MIC values. The cepA gene occurred at different frequencies among Bacteroides fragilis and non-fragilis Bacteroides strains. The cfxA gene was not a major factor in determining cefoxitin resistance and it was found with higher prevalence in non-fragilis Bacteroides strains than in B. fragilis. Among the five possible clindamycin resistance genes, ermF was the most common and had the highest effect on clindamycin resistance after linA. The ermG-mefA-msrSA combination was found in a set of strains and their linked occurrence implied that they were harbored by the conjugative transposon CTnGERM1. All strains tested were susceptible to metronidazole and none of them harbored nim genes. TetQ was prevalent among both the B. fragilis and non-fragilis Bacteroides strains (78.9 and 84.8%, respectively) and no gene could be clearly linked to tigecycline resistance other than tetQ. BexA, which codes for the fluoroquinolone efflux pump, was found in 7.5% of strains and occurred at different frequencies among B. fragilis and non-fragilis Bacteroides strains, but was represented only in a minor proportion of moxifloxacin-resistant strains.
  Highlights ► 16 antibiotic resistance genes were detected by PCR among 161 Bacteroides isolates. ► cepA might not be the only factor in ampicillin resistance and was found among NFB. ► The MLS-B resistance was mediated mainly by ermF with a ca. 75% prevalence. ► tetQ was the only tetracycline-resistance gene among tigecycline-resistant strains. ► BexA was a frequently detected gene but it occurred only in one moxifloxacin-resistant strain.
  
  PubDate: 2013-03-15T07:18:44Z
In vitro inhibition of Clostridium difficile and Clostridium perfringens by commercial probiotic strains
- Abstract: Available online 5 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  Probiotics have gained importance in human and veterinary medicine to prevent and control clostridial enteric disease. Limited information is available on the ability of different probiotic bacteria used in food products to inhibit Clostridium difficile and Clostridium perfringens. The objective of this study was to examine the in vitro inhibitory effects of selected commercial bacterial strains on pathogenic clostridia and their growth characteristics under simulated gastrointestinal conditions. The inhibitory effects of 17 commercial strains of Lactobacillus (n = 16) and Bifidobacterium (n = 1) on the reference strains of C. difficile and C. perfringens were assessed by an agar well diffusion assay and by a broth culture inhibition assay using cell-free supernatant harvested at different growth phases, with and without pH neutralization. To study growth characteristics, probiotic strains were cultivated in different acid and bile environments, and growth in the modified media was compared to growth in standard medium. In the agar well diffusion assay, supernatant obtained from two probiotic strains inhibited the growth of both reference and clinical strains of C. perfringens. This effect as seen when supernatant was assessed with and without pH neutralization. Supernatants obtained from 10 probiotic strains inhibited C. difficile only when supernatant was added without pH neutralization. In the broth culture inhibition assay, growth of C. perfringens and C. difficile was inhibited by supernatant without pH neutralization from 5 and 10 probiotic strains, respectively. All potential probiotic strains were able to grow at pH 4.0 and in the presence of 0.15% and 0.3% bile but none were able to grow or survive at pH 2.0. Altogether five probiotic strains [Lactobacillus plantarum (n = 2), Lactobacillus rhamnosus (n = 2), Bifidobacterium animalis lactis (n = 1)] were shown to inhibit all strains of C. difficile and C. perfringens. The inhibitory effect was probiotic strain-specific. Two strains showed a pH-independent inhibitory effect likely due to production of either antibiotics or bacteriocins inhibiting C. perfringens only. These strains have favourable growth characteristics for use as probiotics and their efficacy as prophylactic or therapeutic measures against clostridial enteric disease should be further evaluated by clinical trials in animals.
  Highlights ► The inhibition of Clostridium perfringens and C lostridium difficile by commercial bacteria was tested. ► 2 Lactobacillusplantarum, 2 Lactobacillus rhamnosus, and 1 Bifidobacterium animalis lactis inhibited both clostridia. ► Inhibition was likely due to the acidic environment from organic acid production. ► L . plantarum LPAL and B. animalis lactis BLC1 produce an antimicrobial compound. ► These strains have favorable growth characteristics for use as probiotics.
  
  PubDate: 2013-03-07T22:00:19Z
Grain-rich diets differently alter ruminal and colonic abundance of microbial populations and lipopolysaccharide in goats1
- Abstract: Available online 5 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  High grain feeding has been associated with ruminal pH depression and microbial dysbiosis in cattle. Yet, the impact of high grain feeding on the caprine rumen and hindgut microbial community and lipopolysaccharide (LPS) release is largely unknown. Therefore, the objective was to investigate the effect of increasing dietary levels of barley grain on the microbial composition and LPS concentrations in the rumen and colon of goats. Effects were compared with respect to the responses of ruminal and colonic pH and short-chain fatty acid (SCFA) generation. Growing goats (n = 5-6) were fed diets containing 0, 30, or 60% coarsely ground barley grain for 6 weeks. Ruminal ciliate protozoa were counted with Bürker counting chamber, and quantitative PCR was used to compare bacterial populations. Increasing dietary grain level linearly increased (P
  PubDate: 2013-03-07T22:00:19Z
Clostridium difficile-associated diarrhea in an ocelot (Leopardus pardalis)
- Abstract: Available online 4 March 2013
  Publication year: 2013
  Source:Anaerobe
  
  The aim of this study is to report a case of C lostridium difficile-associated diarrhea in an ocelot (Leopardus pardalis) in the state of Mato Grosso do Sul, Brazil. The animal, a 24-month-old male, was referred to the Centro de Reabilitação de Animais Silvestres (CRAS) with a history of having been run over and tibia and fibula fractures. After a surgery to repair the fractures, the ocelot underwent antibiotic therapy with two doses of sodium cefovecin, during which he presented with diarrhea. A stool sample was positive for A/B toxins by a cytotoxicity assay, and a toxigenic strain of C. difficile was isolated. No other enteropathogens were detected. The association between the history, clinical signs and laboratory exams confirmed the diagnosis of C. difficile-associated diarrhea. The present report confirms C. difficile as a potential pathogen for wild felids and suggests that the C. difficile-associated diarrhea should be considered in diarrhea cases, especially when the clinical signs began after antimicrobial use.
  
  PubDate: 2013-03-07T22:00:19Z
Study of the effects of chitosan upon Streptococcus mutans adherence and biofilm formation
- Abstract: Available online 27 February 2013
  Publication year: 2013
  Source:Anaerobe
  
  The main aim of this work was to access the potential use of high and low molecular weight chitosan as potential oral antimicrobials, particularly as antibiofilm agents.Chitosan’s interference with Streptococcus mutans capability to adhere and form biofilms was assessed. Additionally the effect upon mature biofilms and polymicrobial was also evaluated. The results obtained showed that chitosan was capable of interfering with S. mutans adhesion and primary biofilm formation.This action was observed up to a week with little to none decrease in efficiency. In addition chitosan was capable of inhibiting biofilms formed by two microorganisms and was capable of acting upon mature biofilms leading to significant reductions (94%) in biofilm survival. However clear statistical differences (p
  PubDate: 2013-02-28T22:21:42Z
Proteolytic activity of probiotic strain Lactobacillus helveticus M92
- Abstract: Available online 27 February 2013
  Publication year: 2013
  Source:Anaerobe
  
  The aim of this research was to investigate the potential of previously defined probiotic strain Lactobacillus helveticus M92 as functional starter culture for fermented dairy products. Therefore, proteolytic activity of L. helveticus M92 was investigated and compared with those of different representatives of probiotic and starter culture strains. Cluster analysis of AFLP fingerprints showed a difference of L. helveticus M92 compared to five other L. helveticus strains, but the percentage of similarity confirmed the identification on species level. Casein hydrolysis by L. helveticus M92 was monitored by agar-well diffusion test, SDS-PAGE and Anson´s method. L. helveticus M92 exhibited the highest proteolytic activity among tested probiotic and starter cultures strains with the fastest acidification rate and the highest pH decrease after overnight incubation in skim milk. The presence of prtH2 gene was confirmed by PCR amplification with specific primers, while PCR product was not obtained after amplification with primers specific to prtH. Furthermore, SDS-PAGE LC-MS/MS analysis of insoluble proteome of L. helveticus M92 enabled identification of several proteins involved in proteolytic system of L. helveticus such as protease PrtM as well as proteins involved in Opp peptide transport system and the intracellular peptidases PepE, PepN, and PepQ.
  Highlights ► Proteolytic activity of Lactobacillus helveticus M92 was observed. ► prtH2 encoding cell envelope proteinase was detected in L. helveticus M92. ► PrtM required for protein maturation and Opp transport system proteins were identified by LC-MS/MS. ► Set of intracellular peptidases were identified by LC-MS/MS.
  
  PubDate: 2013-02-28T22:21:42Z
MALDI-TOF MS fingerprinting facilitates rapid discrimination of phylotypes I, II and III of Propionibacterium acnes
- Abstract: Available online 26 February 2013
  Publication year: 2013
  Source:Anaerobe
  
  Matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is widely used today for species determination of bacteria and fungi in routine microbiological laboratories, and can also be used for subtyping of bacteria, such as Bacteroides fragilis. Propionibacterium acnes is frequently referred to as an anaerobic skin commensal of relatively low pathogenicity. In addition to its accepted pathogenic role in acne, P. acnes is now emerging as an important opportunistic pathogen in many other clinical situations, including late-stage prosthetic joint infections, osteomyelitis, endocarditis, endophthalmitis, post-neurosurgical infections and possibly prostate cancer. At the population genetic level, P. acnes can be differentiated into a number of distinct phylogroups, known as types IA1, IA2, IB, IC, II and III, which may be associated with different types of infections and clinical conditions. The aim of the present study was to evaluate MS-based typing for resolution of these genetic groups after routine identification by MALDI-TOF MS (Bruker MALDI Biotyper). The software package ClinProTools 2.2 was used to analyse the protein based mass spectra of reference strains belonging to types IA, IB, IC, II and III. Phylogroup-specific peaks and peak shifts were then identified visually. In addition, peak variations between the different types of P. acnes were investigated by using FlexAnalysis 3.3 software (Bruker). A differentiating library was created, which was used to type further 48 clinical isolates of P. acnes. Typing data obtained by MALDI-TOF MS were then compared with the results from Multilocus Sequence Typing (MLST). Most of the clinical isolates (n=19) belonged to the type IA grouping according to MALDI-TOF MS. By MLST, all isolates were identified as type IA1. Twenty one clinical isolates belonged to the type IB cluster based on both MALDI-TOF MS and MLST typing. Eight clinical isolates were identified as type II strains by both typing methods and all the type III reference strains could be distinguished by the presence of a unique type III-specific peak (7238 Da) by the MALDI-TOF MS. Our study demonstrates that MALDI-TOF MS is a reliable and powerful tool for rapid identification and typing of P. acnes strains from the main genetic divisions of the species.
  Highlights ► P. acnes is an anaerobic bacterium with increasing pathological importance. ► Several phylotypes of P. acnes has been described by MLST typing. ► MALDI-TOF MS is a new methodology for identification of bacteria in a rapid way. ► Using MALDI-TOF MS we could differentiate major phylotypes of P. acnes.
  
  PubDate: 2013-02-28T22:21:42Z
In vitro activity of cadazolid against Clostridium difficile strains isolated from primary and recurrent infections in Stockholm, Sweden
- Abstract: Available online 26 February 2013
  Publication year: 2013
  Source:Anaerobe
  
  One hundred thirty-three Clostridium difficile strains were collected from 71 patients and analyzed for the presence of C. difficile toxin B by the cell cytotoxicity neutralization assay, genes for toxin A, toxin B, binary toxin and TcdC deletion by PCR. All strains were also PCR-ribotyped and analyzed for sporulation frequency. The MICs of the isolates were determined against cadazolid and seven other antimicrobial agents by the agar dilution method. All isolates were positive for toxin B by the cell cytotoxicity neutralization assay. One hundred fourteen isolates were positive for toxin A and B and 16 isolates were positive for toxin A, toxin B and binary toxin by PCR. Three isolates were negative for toxin A but positive for toxin B. Thirty-three different ribotypes were identified. No strain of ribotype 027 was found. No differences in sporulation were noticed between the primary and recurrent isolates. All 133 isolates were sensitive to cadazolid (0.064-0.5 mg/l), fidaxomicin (0.008-0.125 mg/l), metronidazole (0.125-2 mg/l), vancomycin (0.125-1 mg/l) and tigecycline (0.032-0.25 mg/l). Three isolates were resistant to linezolid (8 mg/l), 15 isolates were resistant to moxifloxacin (8-32 mg/l) and 103 isolates were resistant to clindamycin (8-256 mg/l). No association between toxins A, B and binary toxin, ribotypes or the sporulation and the sensitivity to cadazolid could be found. Cadazolid has a potent in vitro activity against C. difficile.
  Highlights ► Cadazolid is a new antibiotic for treatment of Clostridium difficile infections. ► Cadazolid has been tested against 133 C. difficile strains isolated from CDI in Sweden. ► All strains were susceptible to cadazolid. ► Cadazolid has a potent in vitro activity against C. difficile. ► Cadazolid is a promising drug for treatment of CDI and clinical studies are needed.
  
  PubDate: 2013-02-28T22:21:42Z
Community-Associated Clostridium difficile Infection: How Real Is It'
- Abstract: Available online 8 February 2013
  Publication year: 2013
  Source:Anaerobe
  
  Community-associated Clostridium difficile infection (CA-CDI) represents 32% of all CDI cases based on U.S. population-based data. The current epidemic strain, NAP1, is the most prevalent strain causing these infections. Although complications, recurrence and death are uncommon, one fourth of the CA-CDI patients are hospitalized within 7 days after the diagnosis.
  Highlights ► 32% of all C.difficile infections are community-associated. ► Recurrences are less common in community-associated C. difficile infections. ► One fourth of community-associated C. difficile infections are caused by NAP1
  
  PubDate: 2013-02-11T22:26:54Z
Microbial ecosystem and fermentation traits in the caecum of growing rabbits given diets varying in neutral detergent soluble and insoluble fibre levels
- Abstract: Available online 9 February 2013
  Publication year: 2013
  Source:Anaerobe
  
  The effect of the level of neutral detergent fibre (NDF: 0.35, LI and 0.42, HI) and neutral detergent soluble fibre (NDSF: 0.14, LS and 0.17, HS) caecal ecosystem was studied in 24 weaned (28 days of age) rabbits, weighing 630 ± 80.2 g in a 2x2 factorial design. After 22 days, rabbits were slaughtered and their caecal contents sampled. The caecal pH (on average 6.2) and molar volatile fatty acids (VFA) proportions were not affected by dietary treatments, but total VFA concentration tended to be lower with NDF (84.7 vs. 74.1 mmol/l; P=0.095). The amount of total bacteria tended (P=0.075) to increase with NDSF, but only in diets with 0.35 NDF. The caecal proportions of Ruminococcus albus and Fibrobacter succinogenes were not affected by type or level of fibre, but Butyrivibrio fibrisolvens decreased (P=0.055) with the NDF proportion in LS diets. Denaturing gradient gel electrophoresis (DGGE) analysis showed that bacterial communities clustered according to each combination of NDF and NDSF, but did not greatly differ among diets (similarity indexes between 0.67 and 0.70), nor biodiversity was affected (average Shannon and richness indexes 3.50 and 33.1; P>0.10). Archaeal population revealed changes in the amount and composition that were particularly evident in HS diets, decreasing in concentration (from 4.37 to 4.12 log10 gene copy number/g) and biodiversity (Shannon index from 3.14 to 2.52 and richness index from 23.7 to 13.9) compared to LS. The type and level of dietary fibre had a minor impact on caecal fermentation traits or caecal bacterial community. However, the increase in NDSF from 0.14 to 0.17 reduced concentration and diversity of methanogenic archaea.
  Highlights ► The effect of NDF and NDSF level on caecal ecosystem of growing rabbit was studied. ► The type and level of fibre in diet did not affect caecal environmental traits. ► The high NDSF level increased total bacterial concentration in diets low in NDF. ► Diets promoted minor differences in bacterial profile, and diversity was not affected. ► NDSF, but not NDF, decreased total concentration and microbial diversity of archaea
  
  PubDate: 2013-02-11T22:26:54Z
Glyphosate suppresses the antagonistic effect of Enterococcus spp. on Clostridium botulinum
- Abstract: Available online 6 February 2013
  Publication year: 2013
  Source:Anaerobe
  
  During the last 10 to15 years, an increase of C. botulinum associated diseases in cattle has been observed in Germany. The reason for this development is currently unknown. The normal intestinal microflora is a critical factor in preventing intestinal colonisation by C. botulinum as shown in the mouse model of infant botulism. Numerous bacteria in the gastro-intestinal tract (GIT) produce bacteriocines directed against C. botulinum and other pathogens: Lactic acid producing bacteria (LAB) such as lactobacilli, lactococci and enterococci, generate bacteriocines that are effective against Clostridium spp. A reduction of LAB in the GIT microbiota by ingestion of strong biocides like glyphosate could be an explanation for the observed increase in levels of C. botulinum associated diseases. In the present paper, we report on the toxicity of glyphosate to the most prevalent Enterococcus spp. in the GIT. Ingestion of this herbicide could be a significant predisposing factor that is associated with the increase in C. botulinum mediated diseases in cattle.
  
  PubDate: 2013-02-08T07:01:38Z
Eleutherine americana as a growth promotor for infant intestinal microbiota
- Abstract: Available online 30 January 2013
  Publication year: 2013
  Source:Anaerobe
  
  Eleutherine americana extract and its oligosaccharides extract were demonstrated for their growth-promoting activities on mixed infant intestinal microbiota and individual bacterial species including Bacteroides, bifidobacteria, clostridia, and lactobacilli. Fermentation of all the substrates resulted in about 1-2 log increase in the numbers of bifidobacteria belonging to the dominant infant gut microbiota. The highest levels of the bacterial populations were resulted from the oligosaccharides extract. The oligosaccharides extract stimulated the growth of bifidobacteria in mixed and individual populations by increasing their numbers from 9.63 to 12.08 and 5.80 to 8.85 log cfu/ml, respectively within 48 h. In addition, Bacteroides populations were enhanced by fermentation of E. americana extract. Increase in lactobacilli level was observed from fermentation by a single bacterial species, but not from the mixed cultures. Fermentation of the extract, oligosaccharides extract, and commercial fructo-oligosaccharides by both mixed and individual intestinal microbiota resulted in increase in the production of short chain fatty acids. Acetic acid production was predominant, followed by lactic acid and minor amount of propionic and butyric acids. The highest production of acetic acid was resulted from the oligosaccharides extract. Increase in the acetic acid in mixed and individual species of bifidobacterial populations ranged from 1.21 to 34.26 and 1.02 to 25.21 mM, respectively. This study showed that E. americana can be considered as a potential prebiotic which may be supplemented as an ingredient in functional foods.
  
  PubDate: 2013-01-31T04:36:02Z
Antimicrobial and antifungal activities of Lactobacillus curvatus strain isolated from homemade Azerbaijani cheese
- Abstract: Available online 25 January 2013
  Publication year: 2013
  Source:Anaerobe
  
  The aims of this study were to characterize inhibitory activity spectra, some probiotic properties and safety of Lactobacillus curvatus A61 for its future application in production of fermented foods. The studied strain was isolated from traditional homemade cheese manufactured in Azerbaijan. The cell-free supernatant of culture of Lb. curvatus A61 inhibited the growth of tested LAB, as well as of Listeria monocytogenes and Bacillus cereus strains. The strain presented antifungal activity and inhibited the growth of Cladosporium and Fusarium ssp. during co-cultivation on agar media. PCR amplification with specific primers revealed the presence of curvacin A encoding gene in Lb. curvatus A61. Bacteriocin produced by the studied strain was heat stable and active in a broad pH range, and in the presence of Triton X-20, Triton X-80, Triton X-100, β-mercaptoethanol, Na-EDTA, SDS and NaCl. The mode of action of bacteriocin against selected indicator strains was found to be bacteriostatic. Lb. curvatus A61 was resistant to physiological concentrations of bile salts and showed high auto-aggregation ability, as well as co-aggregation ability with pathogenic Listeria monocytogenes strains. It was sensitive to chloramphenicol, penicillin, tetracycline, ciprofloxacin and vancomycin, but resistant to ampicillin and gentamicin.
  Highlights ► Bacteriocin producing Lb. curvatus strain with strong antilisterial activity was isolated. ► Antifungal activity against Cladosporium and Fusarium ssp. was detected. ► The strain exhibited the presence of curvacin A encoding gene. ► Bacteriocin was heat and pH stable and its mode of action was bacteriostatic.
  
  PubDate: 2013-01-28T00:18:13Z
Editorial board
- Abstract: February 2013
  Publication year: 2013
  Source:Anaerobe, Volume 19
  
  PubDate: 2013-01-24T21:44:20Z
Sudden death syndrome in adult cows associated with Clostridium perfringens type E
- Abstract: Available online 24 January 2013
  Publication year: 2013
  Source:Anaerobe
  
  Clostridium perfringens type E is considered a rare toxinotype and an infrequent cause of enterotoxemia of lambs, calves, and rabbits. Until now, only cases of young animal of C. perfringens type E bovine enterotoxemia, characterized by hemorrhagic enteritis and sudden death, have been reported. The present report details the genotypic characterization of C. perfringens type E isolates obtained from intestinal samples of adult cattle during an outbreak of enterotoxemia in Argentina. The sequences of several housekeeping genes of these isolates were analyzed and compared with those obtained from calves in North America showing a clonal unique lineage.
  Highlights ► C.perfringens type E cause hemorrhagic enteritis in adult cattle. ► Type E strains share a common genetic background. ► Combination of plasmid genes with chromosomal genes increases host fitness.
  
  PubDate: 2013-01-24T21:44:20Z
Development of antimicrobial synbiotics using potentially-probiotic faecal isolates of Lactobacillus fermentum and Bifidobacterium longum
- Abstract: Available online 24 January 2013
  Publication year: 2013
  Source:Anaerobe
  
  The aims of the present study were to investigate in vitro the antimicrobial activity of Lactobacillus fermentum and Bifidobacterium longum, isolated from faeces of healthy elderly individuals, against enterohaemorrhagic Escherichia coli (E. coli O157:H7) and enteropathogenic E. coli (E. coli O86), to determine the capability of the selected strains to tolerate acid and bile in vitro, to select suitable carbohydrates in order to enhance the growth and maximise antimicrobial activity of the putative probiotic organisms and examine the adhesion properties of the synbiotics. Antimicrobial activity of the putative probiotics and synbiotics was investigated by a microtitre method using cell-free culture supernatants (CFCS). Results of the antimicrobial assay showed that both putative probiotic strains produced compounds at pH 5 that lead to higher lag phases of both E. coli O157:H7 and E. coli O86. When half the quantity of cell-free culture supernatants of both probiotic strains was used at pH 5, B. longum maintained the same antimicrobial effect against both strains of E. coli, whereas L. fermentum lead to a higher lag phase of E. coli O86 only. Neutralization of the culture supernatants with alkali reduced the antimicrobial effect with only cell-free supernatant of L. fermentum causing lower maximum growth rates of E. coli O157:H7 and E. coli O86. L. fermentum appeared to be acid tolerant whereas B. longum was more susceptible to acid and both isolates were bile tolerant. A short chain fructooligosaccharide (scFOS) and an isomalto-oligosaccharide (IMO) proved to be the most effective substrates, enhancing antimicrobial activity for L. fermentum and B. longum respectively. The adhesion of the synbiotic combinations showed that L. fermentum, exhibited higher percentage of adhesion when grown on glucose and as a synbiotic combination with scFOS whereas B. longum exhibited lowest percentage of adhesion when grown on both glucose and IMO.
  Highlights ► L. fermentum and B. longum isolated from faecal samples of elderly. ► Both strains exhibited antimicrobial activity against E. coli.. . ► Both putative probiotic strains exhibited good acid and bile tolerance. ► Antimicrobial synbiotics of L. fermentum with scFOS and B. longum with IMO chosen. ► L. fermentum with scFOS exhibited good adhesion properties.
  
  PubDate: 2013-01-24T21:44:20Z
Isolation of Robinsoniella peoriensis from the fecal material of the endangered Yangtze finless porpoise, Neophocaena asiaeorientalis asiaeorientalis
- Abstract: Available online 5 January 2013
  Publication year: 2013
  Source:Anaerobe
  
  The aim of this study was to determine the causative agent of diarrhea in an endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis). From the fecal material collected from this porpoise Robinsoniella peoriensis was isolated.
  Highlights ► We wished to determine if Clostridium difficile caused diarrhea in a Yangtze finless porpoise. ► DNA was isolated from diarrheic fecal material and subject to PCR amplification. ► No bands were detected suggesting C. difficile was not present in the feces. ► To try to cultivate the organism a Blood Agar plate was inoculated. ► Robinsoniella peoriensis was isolated, not C. difficile.
  
  PubDate: 2013-01-10T05:53:36Z
Effects of Withania somnifera on the growth and virulence properties of Streptococcus mutans and Streptococcus sobrinus at sub-MIC levels
- Abstract: Available online 6 November 2012
  Publication year: 2012
  Source:Anaerobe
  
  The aim of this study was to evaluate the effect of the methanol extract of Withania somnifera (MEW) on the growth and virulence properties of Streptococcus mutans and Streptococcus sobrinus at sub-minimum inhibitory concentration (MIC) levels and to identify the main components of MEW. First, antibacterial activity of MEW against oral bacteria was determined using a micro-dilution method. Then, the effect of MEW on the growth of S. mutans and S. sobrinus was investigated at sub-MIC levels. To test the effect of MEW on the virulence properties of S. mutans and S. sobrinus, assays for acid production, acid tolerance, and biofilm formation were performed at sub-MIC levels. A GC–MS analysis for the main components of MEW was also carried out. MEW showed a broad antibacterial range against oral bacteria (MIC: 0.125–2 mg/mL). At sub-MIC levels, MEW dose-dependently increased doubling times of S. mutans and S. sobrinus up to 258% and 400%, respectively. Furthermore, MEW inhibited acid production, acid tolerance, and biofilm formation of S. mutans and S. sobrinus at sub-MIC levels. The GC–MS analysis revealed the presence of mono- and disaccharides, sugar alcohols, and organic acids as main components. These data suggest that MEW might be useful for restraining physiological activities of cariogenic bacteria.
  Highlights ► Effect of Withania somnifera extract on cariogenic bacteria was determined. ► The extract was mainly composed of sugars and organic acids. ► The extract inhibited the growth and virulence properties of cariogenic bacteria. ► The extract might be useful for the prevention of dental caries.
  
  PubDate: 2012-12-15T21:38:31Z
Assessment of intestinal microbiota modulation ability of Bifidobacterium strains in in vitro fecal batch cultures from preterm neonates
- Abstract: Available online 12 November 2012
  Publication year: 2012
  Source:Anaerobe
  
  Microbial colonization of the infant gut is essential for the development of the intestine and the immune system. The intestinal microbiota of full-term breast-fed infants is considered as the health standard for newborns. A culture medium containing formula milk was designed, which allowed a balanced growth of intestinal microorganisms and was used to perform fecal batch cultures from preterm babies. Sixteen Bifidobacterium strains and fructooligosaccharides (FOS) were tested for their ability to modulate in vitro the intestinal microbiota. The production of short chain fatty acids (SCFA) was measured by Gas Chromatography and the levels of some anaerobe (Bifidobacterium and Bacteroides groups) and facultative anaerobes (Enterobacteriaceae, Enterococcaceae, Weissella group, and Klebsiella pneumoniae) were determined by quantitative PCR. Results were referred to a fecal negative control culture without microorganisms or FOS added. Strains that in fecal cultures counteracted better the aberrancies previously found in feces of preterm babies, as compared with full-term breast-fed infants, were selected. The three Bifidobacterium bifidum strains tested in this work promoted the most suitable shifts in SCFA and in the ratio of variables facultative anaerobes to anaerobes. Two Bifidobacterium breve strains complied with the requirement for facultative anaerobes and anaerobes and one of them also promoted a suitable shift of SCFA. Bifidobacteria behaved similarly as FOS regarding the microbial profiles in fecal cultures but the production of lactic and acetic acid was much lower. B. breve and B. bifidum strains selected represent promising candidates for their assessment in more complex in vitro and in vivo models.
  Highlights ► Bifidobacteria were tested for microbiota modulation in premature fecal culture models. ► Three Bifidobacterium bifidum and one Bifidobacterium breve strains were the most effective. ► They promoted the most suitable short chain fatty acid profiles during incubation. ► They caused convenient shifts in the facultative anaerobes to anaerobes ratio.
  
  PubDate: 2012-12-15T21:38:31Z
Antimicrobial effect of sophoraflavanone G isolated from Sophora flavescens against mutans streptococci
- Abstract: Available online 22 November 2012
  Publication year: 2012
  Source:Anaerobe
  
  In this study, the antibacterial properties of sophoraflavanone G isolated from the methanol extract of Sophora flavescens were tested against 16 strains of mutans streptococci to screen and determine the optimal concentration of anti-caries natural extract. The antimicrobial activity was evaluated by measuring minimum bactericidal concentration (MBC). The cell viability of normal human gingival fibroblast (NHGF) cells was tested using the methyl thiazolyl tetrazolium assay after exposure to sophoraflavanone G. The data showed that sophoraflavanone G had a remarkable antimicrobial effect on the bacteria tested with an MBC ranging from 0.5 μg/ml to 4 μg/ml. Sophoraflavanone G had no cytotoxic effect on NHGF cells at concentrations where it produced an antimicrobial effect. These findings demonstrate that sophoraflavanone G has strong antimicrobial activity against mutans streptococci and could be useful in the development of novel oral hygiene products, such as a gargle solution or dentifrice.
  Highlights ► Sophoraflavanone G (SG) isolated from the methanol extract of Sophora flavescens. ► Bacterial model system was used for determining the anticariogenic effect. ► SG displayed no cytotoxic effect against NHGF cells at anticariogenic concentration.
  
  PubDate: 2012-12-15T21:38:31Z
Fecal microbiome transplantation for recurrent Clostridium difficile infection: Report on a case series
- Abstract: Available online 23 November 2012
  Publication year: 2012
  Source:Anaerobe
  
  Background Clostridium difficile infection (CDI) continues to increase in incidence and severity, and was the most common nosocomial infection in the USA in 2010. Most cases of CDI respond to a standard course of antibiotics, but recurrent C. difficile infection (RCDI) has become increasingly frequent, and alternative treatments are needed. We examined the efficacy of fecal microbiota transplantation (FMT) instilled into the upper gastrointestinal tract for RCDI. Materials and methods The medical records for all patients treated with FMT during a 9-year period at a single institution in northern Minnesota were reviewed retrospectively. Eighty-nine FMT courses were provided by nasogastric tube to 87 patients, and demographic and clinical data were abstracted, including details of treatments prior to FMT, rate of FMT treatment success and clinical course during a 60-day post FMT follow up period. Fourteen FMT courses failed to meet criteria for inclusion. Results Each patient served as his or her own control, having failed standard treatment. After exclusions, the case series included 75 FMT courses administered to 74 patients. Fifty-nine FMT courses resulted in clinical resolution of diarrhea for a primary cure rate of 79%. Diarrhea relapsed following 16 FMT courses; in 9 of these cases diarrhea subsequently resolved after a single course of vancomycin. No adverse events were noted. Conclusions Our findings parallel findings from other studies when FMT has been provided via the upper GI tract, and suggest that patients with recurrent CDI may resolve diarrhea by introducing stool from healthy donors into the upper GI tract via nasogastric tube.
  Highlights ► Stool transplantation for patients with recurrent Clostridium difficile infection. ► This is the largest case series of stool transplantation submitted for publication. ► All patients had prior treatment with vancomycin and multiple prior recurrences. ► Stool transplantation led to clinical resolution in 79% of patients.
  
  PubDate: 2012-12-15T21:38:31Z