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Sample records for enumerating clostridium perfringens

  1. Comparison of media for enumeration of Clostridium perfringens from foods

    NARCIS (Netherlands)

    Jong, A.E.I. de; Eijhusen, G.P.; Brouwer-Post, E.J.F.; Grand, M.; Johansson, T.; Kärkkäinen, T.; Marugg, J.; Veld, P.H. in 't; Warmerdam, F.H.M.; Wörner, G.; Zicavo, A.; Rombouts, F.M.; Beumer, R.R.

    2003-01-01

    Many media have been developed to enumerate Clostridium perfringens from foods. In this study, six media [iron sulfite (IS) agar, tryptose sulfite cycloserine (TSC) agar, Shahidi Ferguson perfringens (SFP) agar, sulfite cycloserine azide (SCA), differential clostridial agar (DCA), and oleandomycin

  2. Optimizing sporulation of Clostridium perfringens

    NARCIS (Netherlands)

    Jong, de A.E.I.; Beumer, R.R.; Rombouts, F.M.

    2002-01-01

    Many sporulation media have been developed for Clostridium perfringens, but none stimulates sporulation for all strains. The aim of our experiments was to develop a sporulation method using Duncan and Strong (DS) medium, which supports sporulation of a wide variety of strains. Different inoculation

  3. Toxinas de Clostridium perfringens Toxins of Clostridium perfringens

    Directory of Open Access Journals (Sweden)

    W. E. Morris

    2009-12-01

    Full Text Available Clostridium perfringens es un bacilo grampositivo anaerobio con capacidad de formar esporas. Es uno de los patógenos bacterianos con mayor distribución en el medio ambiente, ya que puede ser aislado de muestras de suelo y de agua y además forma parte de la microbiota intestinal de animales y humanos. Sin embargo, en ciertas ocasiones puede actuar como patógeno oportunista y causar enfermedades como la gangrena gaseosa, la enterotoxemia del ovino y del caprino y la disentería del cordero, entre otras. En humanos, está asociado a enfermedades como la intoxicación por alimentos, la enterocolitis necrotizante en niños y la enteritis necrótica o pigbel de las tribus de Papúa-Nueva Guinea. El renovado interés que existe actualmente en el estudio de C. perfringens como patógeno veterinario y humano, junto con el avance de la biología molecular, han hecho posible que la ciencia tenga hoy un conocimiento más profundo sobre la biología y la patogenia de esta bacteria. En esta revisión bibliográfica se discuten y actualizan los principales aspectos de la patogenia intestinal de C. perfringens teniendo en cuenta las toxinas con mayor importancia médica descritas hasta el presente.Clostridium perfringens is an anaerobic gram-positive spore-forming bacillus. It is one of the pathogens with larger distribution in the environment; it can be isolated from soil and water samples, which also belongs to the intestinal flora of animals and humans. However, on some occasions it can act as an opportunistic pathogen, causing diseases such as gas gangrene, enterotoxemia in sheep and goats and lamb dysentery, among others. In human beings, it is associated to diseases such as food poisoning, necrotic enterocolitis of the infant and necrotic enteritis or pigbel in Papua-New Guinea tribes. The renewed interest existing nowadays in the study of C. perfringens as a veterinarian and human pathogen, together with the advance of molecular biology, had enabled

  4. Behavior of Clostridium perfringens at low temperatures

    NARCIS (Netherlands)

    Jong, de A.E.I.; Rombouts, F.M.; Beumer, R.R.

    2004-01-01

    Refrigerated storage is an important step in the preparation of foods and inadequate storage is one of the main causes of food poisoning outbreaks of Clostridium perfringens. Therefore, growth and germination characteristics of C. perfringens in a temperature range of 3-42 degreesC were determined

  5. Effect of cooling on Clostridium perfringens in pea soup

    NARCIS (Netherlands)

    Jong, de A.E.I.; Rombouts, F.M.; Beumer, R.R.

    2004-01-01

    Foods associated with Clostridium perfringens outbreaks are usually abused after cooking. Because of their short generation times, C. perfringens spores and cells can grow out to high levels during improper cooling. Therefore, the potential of C. perfringens to multiply in Dutch pea soup during

  6. Clostridium perfringens isolate typing by multiplex PCR

    Directory of Open Access Journals (Sweden)

    MR Ahsani

    2010-01-01

    Full Text Available Clostridium perfringens is an important pathogen that provokes numerous different diseases. This bacterium is classified into five different types, each of which capable of causing a different disease. There are various methods for the bacterial identification, many are labor-intensive, time-consuming, expensive and also present low sensitivity and specificity. The aim of this research was to identify the different types of C. perfringens using PCR molecular method. In this study, 130 sheep-dung samples were randomly collected from areas around the city of Kerman, southeastern Iran. After processing and culturing of samples, the produced colonies were morphologically studied, gram stain test was also carried out and the genera of these bacteria were identified through biochemical tests. DNA extracted from isolated bacteria for genotyping was tested by multiplex PCR with specific primers. Based on length of synthesized fragments by PCR, toxin types and bacterial strains were detected. C. perfringens isolated types were divided as follows: 17.39% type A, 21.74% type B, 34.78% type C and 26.09% type D. It should be emphasized that, up to the present moment, C. perfringens type A has not been reported in Iran.

  7. CLOSTRIDIUM PERFRINGENS IN MEAT AND MEAT PRODUCTS.

    Science.gov (United States)

    HALL, H E; ANGELOTTI, R

    1965-05-01

    A total of 262 specimens of meat and meat dishes were examined for the presence of Clostridium perfringens. Of this total, 161 were raw, unprocessed beef, veal, lamb, pork, or chicken; 101 were processed meats and meat dishes. C. perfringens was isolated from 113 (43.1%) of these specimens. The highest percentage of contamination (82%) was found in veal cuts, and the lowest (4.7%) in sliced sandwich meats and spreads. Only 2 of the 113 isolates were shown to produce heat-resistant spores, which indicates a very low incidence (0.8%) of contamination. These findings indicate that outbreaks of C. perfringens food-borne disease in the Cincinnati area are caused principally by the contamination of the food with vegetative cells or spores of the organism after cooking. Studies of the effects of various holding temperatures on the growth of C. perfringens indicated that, in the range of 5 to 15 C, no multiplication would occur, but that viable cells would still be present at the end of a 5-day holding period. Extremely rapid growth occurred at temperatures around 45 C, and complete inhibition of growth was accomplished between 49 and 52 C.

  8. Perfringolysin O: The Underrated Clostridium perfringens Toxin?

    Science.gov (United States)

    Verherstraeten, Stefanie; Goossens, Evy; Valgaeren, Bonnie; Pardon, Bart; Timbermont, Leen; Haesebrouck, Freddy; Ducatelle, Richard; Deprez, Piet; Wade, Kristin R; Tweten, Rodney; Van Immerseel, Filip

    2015-05-14

    The anaerobic bacterium Clostridium perfringens expresses multiple toxins that promote disease development in both humans and animals. One such toxin is perfringolysin O (PFO, classically referred to as θ toxin), a pore-forming cholesterol-dependent cytolysin (CDC). PFO is secreted as a water-soluble monomer that recognizes and binds membranes via cholesterol. Membrane-bound monomers undergo structural changes that culminate in the formation of an oligomerized prepore complex on the membrane surface. The prepore then undergoes conversion into the bilayer-spanning pore measuring approximately 250-300 Å in diameter. PFO is expressed in nearly all identified C. perfringens strains and harbors interesting traits that suggest a potential undefined role for PFO in disease development. Research has demonstrated a role for PFO in gas gangrene progression and bovine necrohemorrhagic enteritis, but there is limited data available to determine if PFO also functions in additional disease presentations caused by C. perfringens. This review summarizes the known structural and functional characteristics of PFO, while highlighting recent insights into the potential contributions of PFO to disease pathogenesis.

  9. Perfringolysin O: The Underrated Clostridium perfringens Toxin?

    Directory of Open Access Journals (Sweden)

    Stefanie Verherstraeten

    2015-05-01

    Full Text Available The anaerobic bacterium Clostridium perfringens expresses multiple toxins that promote disease development in both humans and animals. One such toxin is perfringolysin O (PFO, classically referred to as θ toxin, a pore-forming cholesterol-dependent cytolysin (CDC. PFO is secreted as a water-soluble monomer that recognizes and binds membranes via cholesterol. Membrane-bound monomers undergo structural changes that culminate in the formation of an oligomerized prepore complex on the membrane surface. The prepore then undergoes conversion into the bilayer-spanning pore measuring approximately 250–300 Å in diameter. PFO is expressed in nearly all identified C. perfringens strains and harbors interesting traits that suggest a potential undefined role for PFO in disease development. Research has demonstrated a role for PFO in gas gangrene progression and bovine necrohemorrhagic enteritis, but there is limited data available to determine if PFO also functions in additional disease presentations caused by C. perfringens. This review summarizes the known structural and functional characteristics of PFO, while highlighting recent insights into the potential contributions of PFO to disease pathogenesis.

  10. A toxic approach to beta2-toxigenic Clostridium perfringens

    NARCIS (Netherlands)

    Allaart, J.G.

    2013-01-01

    Clostridium perfringens is one of the most important causes of intestinal disease in animals and humans. Its virulence is attributed to the several toxins it can produce, including the beta2 toxin encoded by cpb2. In this thesis we studied the role of the beta2 toxin produced by C. perfringens in

  11. Tips to Prevent Illness from Clostridium Perfringens

    Science.gov (United States)

    ... Some strains produce a toxin that causes diarrhea. What are common food sources of C. perfringens ? Meat and poultry are ... Anyone can get food poisoning from C. perfringens . What are the symptoms of C. perfringens food poisoning? People with C. perfringens food poisoning develop ...

  12. Modeling growth of Clostridium perfringens in pea soup during cooling

    NARCIS (Netherlands)

    Jong, de A.E.I.; Beumer, R.R.; Zwietering, M.H.

    2005-01-01

    Clostridium perfringens is a pathogen that mainly causes food poisoning outbreaks when large quantities of food are prepared. Therefore, a model was developed to predict the effect of different cooling procedures on the growth of this pathogen during cooling of food: Dutch pea soup. First, a growth

  13. Occurrence of Clostridium perfringens in sausages sold in Meknes ...

    African Journals Online (AJOL)

    In Morocco, the consumption of meat products has experienced a sharp increase in recent years despite the presence of pathogenic bacteria due to hygiene failure. The present study was designed to determine the prevalence of Clostridium perfringens in sausages sold in Meknes city (Morocco) and to study the different ...

  14. 9 CFR 113.455 - Clostridium Perfringens Type D Antitoxin.

    Science.gov (United States)

    2010-01-01

    ... Clostridium perfringens Type D. Each serial shall be tested as provided in this section. Any serial found... following words and terms shall mean: (i) International antitoxin unit. (I.U.) That quantity of Epsilon... 0.25 gram of sodium chloride in each 100 ml of distilled water; adjusting the pH to 7.2; autoclaving...

  15. 9 CFR 113.454 - Clostridium Perfringens Type C Antitoxin.

    Science.gov (United States)

    2010-01-01

    ... Clostridium perfringens Type C. Each serial shall be tested as provided in this section. Any serial found... following words and terms shall mean: (i) International antitoxin unit. (I.U.) That quantity of Beta... chloride in each 100 ml of distilled water; adjusting the pH to 7.2; autoclaving at 250 °F. for 25 minutes...

  16. Distribution of sewage indicated by Clostridium perfringens at a deep-water disposal site after cessation of sewage disposal.

    OpenAIRE

    Hill, R T; Straube, W L; Palmisano, A C; Gibson, S L; Colwell, R R

    1996-01-01

    Clostridium perfringens, a marker of domestic sewage contamination, was enumerated in sediment samples obtained from the vicinity of the 106-Mile Site 1 month and 1 year after cessation of sewage disposal at this site. C. perfringens counts in sediments collected at the disposal site and from stations 26 nautical miles (ca. 48 km) and 50 nautical miles (ca. 92 km) to the southwest of the site were, in general, more than 10-fold higher than counts from an uncontaminated reference site. C. perf...

  17. EPIDEMIOLOGIC INVESTIGATION OF CLOSTRIDIUM DIFFICILE AND CLOSTRIDIUM PERFRINGENS IN HEALTHY HORSES

    DEFF Research Database (Denmark)

    Schoster, Angelika; Arroyo, Luis; Staempfli, Henry

    Clostridium difficile and Clostridium perfringens are important causes of equine colitis but can also be found in healthy individuals. Epidemiologic information is restricted to cross-sectional studies of fecal shedding with little information on prevalence in gastrointestinal compartments other ...... supports results of previous studies that indicate this organism is rare in healthy horses.......Clostridium difficile and Clostridium perfringens are important causes of equine colitis but can also be found in healthy individuals. Epidemiologic information is restricted to cross-sectional studies of fecal shedding with little information on prevalence in gastrointestinal compartments other...... than feces and variability in shedding over time. The objectives were to investigate the presence of C. difficile and C. perfringens in healthy horses over time and assess prevalence in different gastrointestinal compartments. Feces were collected monthly from 25 horses for one year. Ingesta were...

  18. Clostridium perfringens Sporulation and Sporulation-Associated Toxin Production

    Science.gov (United States)

    Li, Jihong; Paredes-Sabja, Daniel; Sarker, Mahfuzur R.; McClane, Bruce A.

    2015-01-01

    The ability of Clostridium perfringens to form spores plays a key role during the transmission of this Gram-positive bacterium to cause disease. Of particular note, the spores produced by food poisoning strains are often exceptionally resistant to food environment stresses such as heat, cold and preservatives, which likely facilitates their survival in temperature-abused foods. The exceptional resistance properties of spores made by most type A food poisoning strains and some type C foodborne disease strains involves their production of a variant small acid soluble protein-4 that binds more tightly to spore DNA compared to the small acid soluble protein-4 made by most other C. perfringens strains. Sporulation and germination by C. perfringens and Bacillus spp. share both similarities and differences. Finally, sporulation is essential for production of C. perfringens enterotoxin, which is responsible for the symptoms of C. perfringens type A food poisoning, the second most common bacterial foodborne disease in the USA. During this foodborne disease, C. perfringens is ingested with food and then, using sporulation-specific alternate sigma factors, this bacterium sporulates and produces the enterotoxin in the intestines. PMID:27337447

  19. Uterine Clostridium perfringens infection related to gynecologic malignancy.

    Science.gov (United States)

    Kremer, Kevin M; McDonald, Megan E; Goodheart, Michael J

    2017-11-01

    Uterine gas gangrene caused by Clostridium perfringens is a serious, often life-threatening infection that is rarely encountered in the practice of gynecologic oncology. However, the hypoxic nature of gynecologic cancers due to necrosis and/or prior radiation therapy creates a microenvironment optimal for proliferation of anaerobic bacteria such as the Clostridium species. Early recognition and aggressive treatment with IV antibiotics and surgical debridement remain the cornerstones of management in order to decrease morbidity and mortality. Here we present the case of a 52 year-old woman with a remote history of cervical cancer who was previously treated at our institution with primary chemotherapy and radiation and was then admitted decades later with Clostridium perfringens bacteremia and CT evidence of intrauterine abscess. The patient received a prolonged course of IV antibiotic therapy and subsequently underwent definitive surgical management with a total abdominal hysterectomy, bilateral salpingo-oophorectomy, small bowel resection with anastomosis for a utero-ileal fistula identified intraoperatively. Pathology from the uterine specimen demonstrated a primary poorly differentiated uterine adenocarcinoma. The patient recovered fully from her Clostridium perfringens infection and was discharged from the hospital shortly after surgical intervention.

  20. Hazard analysis of Clostridium perfringens in the Skylab Food System

    Science.gov (United States)

    Bourland, C. T.; Huber, C. S.; Kiser, P. R.; Heidelbaugh, N. D.; Rowley, D. B.

    1974-01-01

    The Skylab Food System presented unique microbiological problems because food was warmed in null-gravity and because the heat source was limited to 69.4 C (to prevent boiling in null-gravity). For these reasons, the foods were manufactured using critical control point techniques of quality control coupled with appropriate hazard analyses. One of these hazard analyses evaluated the threat from Clostridium perfringens. Samples of food were inoculated with C. perfringens and incubated for 2 h at temperatures ranging from 25 to 55 C. Generation times were determined for the foods at various temperatures. Results of these tests were evaluated taking into consideration: food-borne disease epidemiology, the Skylab food manufacturing procedures, and the performance requirements of the Skylab Food System. Based on this hazard analysis, a limit for C. perfringens of 100/g was established for Skylab foods.

  1. Calcium Montmorillonite-based dietary supplement attenuates Necrotic Enteritis induced by Eimeria maxima and Clostridium perfringens in broilers

    Science.gov (United States)

    We provide the first description of Dietary Supplement of sorbent minerals attenuates Necrotic Enteritis Induced by Eimeria maxima and Clostridium perfringens in Broilers. Necrotic enteritis (NE) is a poultry disease caused by Clostridium perfringens and characterized by severe intestinal necrosis....

  2. Growth of Clostridium perfringens during cooling of refried beans.

    Science.gov (United States)

    Cevallos-Cevallos, Juan M; Akins, E Deann; Friedrich, Loretta M; Danyluk, Michelle D; Simonne, Amarat H

    2012-10-01

    Outbreaks of Clostridium perfringens have been associated with dishes containing refried beans from food service establishments. However, growth of C. perfringens in refried beans has not been investigated, and predictive models have not been validated in this food matrix. We investigated the growth of C. perfringens during the cooling of refried beans. Refried beans (pinto and black, with and without salt added) were inoculated with 3 log CFU/g C. perfringens spores and incubated isothermally at 12, 23, 30, 35, 40, 45, and 50°C. The levels of C. perfringens were monitored 3, 5, 8, and 10 h after inoculation, and then fitted to the Baranyi primary model and the Rosso secondary model prior to solving the Baranyi differential equation. The final model was validated by dynamic cooling experiments carried out in stockpots, thus mimicking the worst possible food service conditions. All refried beans samples supported the growth of C. perfringens, and all models fit the data with pseudo-R(2) values of 0.95 or greater and mean square errors of 0.3 or lower. The estimated maximum specific growth rates were generally higher in pinto beans, with or without salt added (2.64 and 1.95 h(-1), respectively), when compared with black beans, with or without salt added (1.78 and 1.61 h(-1), respectively). After 10 h of incubation, maximum populations of C. perfringens were significantly higher in samples with no salt added (7.9 log CFU/g for both pinto and black beans) than in samples with salt added (7.3 and 7.2 log CFU/g for pinto and black beans, respectively). The dynamic model predicted the growth of C. perfringens during cooling, with an average root mean squared error of 0.44. The use of large stockpots to cool refried beans led to an observed 1.2-log increase (1.5-log increase predicted by model) in levels of C. perfringens during cooling. The use of shallower pans for cooling is recommended, because they cool faster, therefore limiting the growth of C. perfringens.

  3. Toxinotyping of Clostridium perfringens strains isolated from packed chicken portions

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    Maryam Poursoltani

    2014-06-01

    Full Text Available Background and Aim: Clostridium perfringens are classified into five toxin types A to E, on the basis of production of Alpha, Beta, Epsilon and Iota toxins. Some strains are able to produce enterotoxin, can cause food poisoning in human. The bacteria are able to produce NetB and TpeL toxins which are virulence factors in necrotic enteritis in poultry. The aim of this study was to determine the toxin profile of C. perfringens strains isolated from packed chicken portions using Single and Multiplex PCR assays. Materials and Methods: In a crossectional study, 180 sample of chicken portions including wing (n=50, liver (n=50, neck (n=50 and gizzard (n=30 were collected randomly and examined for C. perfringens contamination. For this purpose all of samples were cultured on the 7% sheep defibrinated blood agar, TSN and TSC culture media. All of the isolates were investigated for the presence of alpha, beta, epsilon, iota toxin and virulence (tpeL and netB genes. Results: In the present study, 6 isolates out of 180 samples, were confirmed as C. perfringens by culture and molecular methods. All of the isolates (100% were confirmed as cpa and cpb positive strains and belong to type C of C. perfringens. The netB gene was detected in 5 isolates (83.33% and tpeL gene in three isolates (50%. Conclusions: Our findings show the majority of C. perfringens in broilers are belong to type C which produce necrotic enteritis in poultry and may be transmitted to human through poultry products.

  4. Experimental Clostridium perfringens type D enterotoxemia in goats.

    Science.gov (United States)

    Uzal, F A; Kelly, W R

    1998-03-01

    The effects of intraduodenal administration of Clostridium perfringens cultures and culture products in goats were evaluated to develop a reliable experimental model of enterotoxemia in this species. Five conventionally reared, 11-16-week-old Angora goat kids were dosed intraduodenally with whole cultures of C. perfringens type D; five similar animals were dosed with C. perfringens type D filtered culture supernatant; and a third group of five kids was dosed with C. perfringens type D washed cells. Two kids were used as controls and received sterile, nontoxic culture medium intraduodenally. All animals received starch solution into the abomasum. All five kids inoculated with whole culture and three of five dosed with culture supernatant and with washed cells developed central nervous system signs. Diarrhea was observed in two of five kids inoculated with whole culture, in all five of those dosed with culture supernatant, and in three of five of those that received washed cells. The most striking postmortem findings consisted of lung edema, necrotizing pseudomembranous colitis, and cerebral vasogenic edema. The protocol thus provided a reasonable model of naturally occurring enterotoxemia in goats, producing a range of clinical signs and postmortem changes similar to those observed in the natural disease.

  5. Recent Insights into Clostridium perfringens Beta-Toxin

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    Masahiro Nagahama

    2015-02-01

    Full Text Available Clostridium perfringens beta-toxin is a key mediator of necrotizing enterocolitis and enterotoxemia. It is a pore-forming toxin (PFT that exerts cytotoxic effect. Experimental investigation using piglet and rabbit intestinal loop models and a mouse infection model apparently showed that beta-toxin is the important pathogenic factor of the organisms. The toxin caused the swelling and disruption of HL-60 cells and formed a functional pore in the lipid raft microdomains of sensitive cells. These findings represent significant progress in the characterization of the toxin with knowledge on its biological features, mechanism of action and structure-function having been accumulated. Our aims here are to review the current progresses in our comprehension of the virulence of C. perfringens type C and the character, biological feature and structure-function of beta-toxin.

  6. Genetic characterization of type A enterotoxigenic Clostridium perfringens strains.

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    Agi Deguchi

    2009-05-01

    Full Text Available Clostridium perfringens type A, is both a ubiquitous environmental bacterium and a major cause of human gastrointestinal disease, which usually involves strains producing C. perfringens enterotoxin (CPE. The gene (cpe encoding this toxin can be carried on the chromosome or a large plasmid. Interestingly, strains carrying cpe on the chromosome and strains carrying cpe on a plasmid often exhibit different biological characteristics, such as resistance properties against heat. In this study, we investigated the genetic properties of C. perfringens by PCR-surveying 21 housekeeping genes and genes on representative plasmids and then confirmed those results by Southern blot assay (SB of five genes. Furthermore, sequencing analysis of eight housekeeping genes and multilocus sequence typing (MLST analysis were also performed. Fifty-eight C. perfringens strains were examined, including isolates from: food poisoning cases, human gastrointestinal disease cases, foods in Japan or the USA, or feces of healthy humans. In the PCR survey, eight of eleven housekeeping genes amplified positive reactions in all strains tested. However, by PCR survey and SB assay, one representative virulence gene, pfoA, was not detected in any strains carrying cpe on the chromosome. Genes involved in conjugative transfer of the cpe plasmid were also absent from almost all chromosomal cpe strains. MLST showed that, regardless of their geographic origin, date of isolation, or isolation source, chromosomal cpe isolates, i assemble into one definitive cluster ii lack pfoA and iii lack a plasmid related to the cpe plasmid. Similarly, independent of their origin, strains carrying a cpe plasmid also appear to be related, but are more variable than chromosomal cpe strains, possibly because of the instability of cpe-borne plasmid(s and/or the conjugative transfer of cpe-plasmid(s into unrelated C. perfringens strains.

  7. Clostridium difficile and Clostridium perfringens from wild carnivore species in Brazil.

    Science.gov (United States)

    Silva, Rodrigo Otávio Silveira; D'Elia, Mirella Lauria; Tostes Teixeira, Erika Procópio; Pereira, Pedro Lúcio Lithg; de Magalhães Soares, Danielle Ferreira; Cavalcanti, Álvaro Roberto; Kocuvan, Aleksander; Rupnik, Maja; Santos, André Luiz Quagliatto; Junior, Carlos Augusto Oliveira; Lobato, Francisco Carlos Faria

    2014-08-01

    Despite some case reports, the importance of Clostridium perfringens and Clostridium difficile for wild carnivores remains unclear. Thus, the objective of this study was to identify C. perfringens and C. difficile strains in stool samples from wild carnivore species in Brazil. A total of 34 stool samples were collected and subjected to C. perfringens and C. difficile isolation. Suggestive colonies of C. perfringens were then analyzed for genes encoding the major C. perfringens toxins (alpha, beta, epsilon and iota) and the beta-2 toxin (cpb2), enterotoxin (cpe) and NetB (netb) genes. C. difficile strains were analyzed by multiplex-PCR for toxins A (tcdA) and B (tcdB) and a binary toxin gene (cdtB) and also submitted to a PCR ribotyping. Unthawed aliquots of samples positive for C. difficile isolation were subjected to the detection of A/B toxins by a cytotoxicity assay (CTA). C. perfringens was isolated from 26 samples (76.5%), all of which were genotyped as type A. The netb gene was not detected, whereas the cpb2 and cpe genes were found in nine and three C. perfringens strains, respectively. C. difficile was isolated from two (5.9%) samples. A non-toxigenic strain was recovered from a non-diarrheic maned wolf (Chrysocyon brachyurus). Conversely, a toxigenic strain was found in the sample of a diarrheic ocelot (Leopardus pardallis); an unthawed stool sample was also positive for A/B toxins by CTA, indicating a diagnosis of C. difficile-associated diarrhea in this animal. The present work suggests that wild carnivore species could carry C. difficile strains and that they could be susceptible to C. difficile infection. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Evaluation of PCR and DNA hybridization protocols for detection of viable enterotoxigenic Clostridium perfringens in irradiated beef

    International Nuclear Information System (INIS)

    Baez, L.A.; Juneja, V.K.; Thayer, D.W.; Sackitey, S.

    1997-01-01

    The sensitivity of DNA hybridization and polymerase chain reaction (PCR), was evaluated in irradiated cooked and raw beef samples. A membrane-based colony hybridization assay and a PCR protocol, both with specificity for the enterotoxin A gene of Clostridium perfringens, were compared with viable plate counts. The results of the colony hybridization procedure were in agreement with viable plate counts for detection and enumeration of enterotoxigenic C. perfringens. The PCR procedure combined a 4 h enrichment followed by a nucleic acid extraction step and assessed the amplification of 183 and 750 base pair enterotoxin gene targets. Detection of C. perfringens by PCR did not show a reliable correlation with viable plate counts or the colony hybridization assay. C. perfringens killed by irradiation were not detected by the plate count or colony hybridization methods; however, killed cells were detected with the PCR technique. By relying on the growth of viable cells for detection and/or enumeration, the colony hybridization and plate count methods provided a direct correlation with the presence of viable bacteria

  9. Strategy to inactivate Clostridium perfringens spores in meat products.

    Science.gov (United States)

    Akhtar, Saeed; Paredes-Sabja, Daniel; Torres, J Antonio; Sarker, Mahfuzur R

    2009-05-01

    The current study aimed to develop an inactivation strategy for Clostridium perfringens spores in meat through a combination of spore activation at low pressure (100-200 MPa, 7 min) and elevated temperature (80 degrees C, 10 min); spore germination at high temperatures (55, 60 or 65 degrees C); and inactivation of germinated spores with elevated temperatures (80 and 90 degrees C, 10 and 20 min) and high pressure (586 MPa, at 23 and 73 degrees C, 10 min). Low pressures (100-200 MPa) were insufficient to efficiently activate C. perfringens spores for germination. However, C. perfringens spores were efficiently activated with elevated temperature (80 degrees C, 10 min), and germinated at temperatures lethal for vegetative cells (>or= 55 degrees C) when incubated for 60 min with a mixture of L-asparagine and KCl (AK) in phosphate buffer (pH 7) and in poultry meat. Inactivation of spores (approximately 4 decimal reduction) in meat by elevated temperatures (80-90 degrees C for 20 min) required a long germination period (55 degrees C for 60 min). However, similar inactivation level was reached with shorter germination period (55 degrees C for 15 min) when spore contaminated-meat was treated with pressure-assisted thermal processing (568 MPa, 73 degrees C, 10 min). Therefore, the most efficient strategy to inactivate C. perfringens spores in poultry meat containing 50 mM AK consisted: (i) a primary heat treatment (80 degrees C, 10 min) to pasteurize and denature the meat proteins and to activate C. perfringens spores for germination; (ii) cooling of the product to 55 degrees C in about 20 min and further incubation at 55 degrees C for about 15 min for spore germination; and (iii) inactivation of germinated spores by pressure-assisted thermal processing (586 MPa at 73 degrees C for 10 min). Collectively, this study demonstrates the feasibility of an alternative and novel strategy to inactivate C. perfringens spores in meat products formulated with germinants specific for C

  10. Distribution of sewage indicated by Clostridium perfringens at a deep-water disposal site after cessation of sewage disposal.

    Science.gov (United States)

    Hill, R T; Straube, W L; Palmisano, A C; Gibson, S L; Colwell, R R

    1996-05-01

    Clostridium perfringens, a marker of domestic sewage contamination, was enumerated in sediment samples obtained from the vicinity of the 106-Mile Site 1 month and 1 year after cessation of sewage disposal at this site. C. perfringens counts in sediments collected at the disposal site and from stations 26 nautical miles (ca. 48 km) and 50 nautical miles (ca. 92 km) to the southwest of the site were, in general, more than 10-fold higher than counts from an uncontaminated reference site. C. perfringens counts at the disposal site were not significantly different between 1992 and 1993, suggesting that sewage sludge had remained in the benthic environment at this site. At stations where C. perfringens counts were elevated (i.e., stations other than the reference station), counts were generally higher in the top 1 cm and decreased down to 5 cm. In some cases, C. perfringens counts in the bottom 4 or 5 cm showed a trend of higher counts in 1993 than in 1992, suggesting bioturbation. We conclude that widespread sludge contamination of the benthic environment has persisted for at least 1 year after cessation of ocean sewage disposal at the 106-Mile Site.

  11. Pancreatitis caused by Clostridium perfringens infection with extensive retropneumoperitoneum

    International Nuclear Information System (INIS)

    Merchante, E.; Garcia, F. J.; Perez, H.; Marquez, J. L.

    2001-01-01

    We present a case of primary emphysematous pancreatitis caused by Clostridium perfringens infection (also Known as spontaneous pancreatic gas gangrene) in a 66-year-old man with diabetes and a history of recurrent pancreatitis. One notable feature is the absence of a focal distribution, which is seen on radiological studies to be accompanied by extensive retropneumoperitoneum, with dissemination of the gas toward the mesenteric root and pelvic extra peritoneal spaces. This wide diffusion is aided by the C. perfringens toxins and the pancreatic enzymes released, leading to a fulminate course, an elevated rate of early mortality among the cases reviewed. The early diagnosis of this disease is fundamental, enabling aggressive medical treatment and emergency surgery. Diabetes is a known risk factor for anaerobic infection, including C. perfringens, as in the case of emphysematous cholecystitis. A diseased pancreas or pancreatic duct facilitates the development of infections since it eliminates poorly the microorganisms that reach it from the duodenum. Gas gangrene secondary to necrosis-related super infection or pancreatic collections is uncommon, and spontaneous or primary cases are exceptionally are. (Author) 13 refs

  12. Uterine Sarcoma Presenting with Sepsis from Clostridium perfringens Endometritis in a Postmenopausal Woman

    Directory of Open Access Journals (Sweden)

    Mary J. Kao

    2018-01-01

    Full Text Available Clostridium perfringens is an anaerobic gram positive rod that is found in normal vaginal and cervical flora in 1–10% of healthy women. Uterine infection with Clostridium perfringens is seen rarely but is often related to underlying uterine pathology and can progress quickly to sepsis. Early recognition of sepsis, prompt treatment with antibiotics, and source control with surgical management allow for optimal chance of recovery. We present a case of a postmenopausal woman who presented with sepsis, vaginal bleeding, and back pain who was found to have Clostridium perfringens infection in the setting of undifferentiated uterine sarcoma.

  13. Cellular Entry of Clostridium perfringens Iota-Toxin and Clostridium botulinum C2 Toxin

    Directory of Open Access Journals (Sweden)

    Masaya Takehara

    2017-08-01

    Full Text Available Clostridium perfringens iota-toxin and Clostridium botulinum C2 toxin are composed of two non-linked proteins, one being the enzymatic component and the other being the binding/translocation component. These latter components recognize specific receptors and oligomerize in plasma membrane lipid-rafts, mediating the uptake of the enzymatic component into the cytosol. Enzymatic components induce actin cytoskeleton disorganization through the ADP-ribosylation of actin and are responsible for cell rounding and death. This review focuses upon the recent advances in cellular internalization of clostridial binary toxins.

  14. Cellular Entry of Clostridium perfringens Iota-Toxin and Clostridium botulinum C2 Toxin.

    Science.gov (United States)

    Takehara, Masaya; Takagishi, Teruhisa; Seike, Soshi; Oda, Masataka; Sakaguchi, Yoshihiko; Hisatsune, Junzo; Ochi, Sadayuki; Kobayashi, Keiko; Nagahama, Masahiro

    2017-08-11

    Clostridium perfringens iota-toxin and Clostridium botulinum C2 toxin are composed of two non-linked proteins, one being the enzymatic component and the other being the binding/translocation component. These latter components recognize specific receptors and oligomerize in plasma membrane lipid-rafts, mediating the uptake of the enzymatic component into the cytosol. Enzymatic components induce actin cytoskeleton disorganization through the ADP-ribosylation of actin and are responsible for cell rounding and death. This review focuses upon the recent advances in cellular internalization of clostridial binary toxins.

  15. Isolation and molecular characterization of Clostridium perfringens from healthy Merino lambs in Patagonia region, Argentina

    DEFF Research Database (Denmark)

    Mignaqui, A. C.; Marcellino, R. B.; Ronco, Troels

    2017-01-01

    The presence and molecular characterization of Clostridium perfringens in healthy Merino lambs over a six-month period was investigated in this study. Overall, a high prevalence of C. perfringens was detected, even in day-old lambs. Even though the majority of the isolates were characterized...

  16. ELIMINATION OF CLOSTRIDIUM PERFRINGENS DURING SURPLUS ACTIVATED SLUDGE HANDLING

    Directory of Open Access Journals (Sweden)

    Klaudiusz Grűbel

    2014-10-01

    Basis on the results of the research was concluded that microwave radiation (700W and 900W shows disintegration action expressed in COD value in the supernatant increase: 12 times increase value of COD with power 700W and 13 times for 900W radiation power. Electromagnetic wave contributed to partial higienisation of surplus activated sludge. The number of Clostridium perfringens decrease about 52% and 56% during the 120s of higienisation process with power 700W and 900W, respectively. Reduction of the overall number of bacteria under the influence of microwave radiation was 42% and 51% (respectively for 700W and 900W, and sticks from the family Enterobacteriaceae from 54% to 70% depending on the power of radiation, the time of operation and biochemical properties.

  17. Stimulation of Clostridium perfringens enterotoxin formation by caffeine and theobromine.

    Science.gov (United States)

    Labbe, R G; Nolan, L L

    1981-01-01

    In the presence of 100 micrograms of caffeine per ml or 200 micrograms of theobromine per ml, sporulation of Clostridium perfringens NCTC 8679 rose from less than 1 to 80 or 85%. Enterotoxin concentration increased from undetectable levels to 450 micrograms/mg of cell extract protein. Heat-resistant spore levels increased from less than 1,000 to between 1 X 10(7) and 2 X 10(7)/ml. These effects were partially reversible by the addition of adenosine or thymidine. In the case of NCTC 8238, caffeine and theobromine caused a three- to fourfold increase in the percentages of cells possessing refractile spores and a similar increase in enterotoxin concentration. Heat-resistant spore levels, however, were unaffected. Inosine was ineffective in promoting sporulation in NCTC 8679. PMID:6271685

  18. The incidence of Clostridioides difficile and Clostridium perfringens netF-positive strains in diarrheic dogs.

    Science.gov (United States)

    Diniz, Amanda Nadia; Coura, Fernanda Morcatti; Rupnik, Maja; Adams, Vicki; Stent, Thomas L; Rood, Julian I; de Oliveira, Carlos Augusto; Lobato, Francisco Carlos Faria; Silva, Rodrigo Otávio Silveira

    2018-02-01

    The aim of this study was to examine the incidence of Clostridioides (previously Clostridium) difficile and Clostridium perfringens in the feces of diarrheic and non-diarrheic dogs. Also, the presence of other common canine enteropathogens was examined. Toxigenic C. difficile and C. perfringens positive for the NetF-encoding gene (netF) were detected in 11 (11.9%) and seven (7.6%) diarrheic dogs, respectively. Three dogs were diagnosed simultaneously with toxigenic C. difficile and netF-positive C. perfringens. Among other enteropathogens, Giardia sp. was the most common agent detected in dogs positive for toxigenic C. difficile or netF-positive C. perfringens. The results suggest that C. difficile and C. perfringens occur more frequently as a primary cause of diarrhea. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Effect of a probiotic on prevention of diarrhea and Clostridium difficile and Clostridium perfringens shedding in foals

    DEFF Research Database (Denmark)

    Schoster, Angelika; Staempfli, H R; Abrahams, M

    2015-01-01

    of incidence and duration of diarrhea and fecal shedding of Clostridium perfringens and Clostridium difficile between treatment and age groups. RESULTS: The overall incidence of diarrhea was 41 of 72 (59%) and did not differ (P = 0.37) between treatment groups. Foals treated with probiotics were more likely...... of C. perfringens shedding was 55% with no difference between treatment groups (P = 0.23). The prevalence of C. difficile shedding was 11%. CONCLUSION AND CLINICAL IMPORTANCE: There was no benefit of administering a 3-week course of probiotics, but potential adverse effects were noted. Whether...

  20. Clostridium perfringens challenge and dietary fat type modifies performance, microbiota composition and histomorphology of the broiler chicken gastrointestinal tract

    DEFF Research Database (Denmark)

    Josefiak, Damian; Swiatkiewicz, S; Kieronczyk, B

    2016-01-01

    Belastung mit Clostridium perfringens und Futterfettquelle modifizieren die Leistung, die Zusammensetzung der Microbiota und die Histomorphologie des Verdauungstraktes beim Broiler......Belastung mit Clostridium perfringens und Futterfettquelle modifizieren die Leistung, die Zusammensetzung der Microbiota und die Histomorphologie des Verdauungstraktes beim Broiler...

  1. Clostridium perfringens in London, July 2009: two weddings and an outbreak.

    OpenAIRE

    Eriksen, J.; Zenner, D.; Anderson, S. R.; Grant, K.; Kumar, D.

    2010-01-01

    : Food poisoning outbreaks caused by Clostridium perfringens enterotoxin occur occasionally in Europe but have become less common in recent years. This paper presents the microbiological and epidemiological results of a large C. perfringens outbreak occurring simultaneously at two weddings that used the same caterer. The outbreak involved several London locations and required coordination across multiple agencies. A case-control study (n=134) was carried out to analyse possible associations b...

  2. Clostridium perfringens Antigens Recognized by Broiler Chickens Immune to Necrotic Enteritis▿

    OpenAIRE

    Kulkarni, R. R.; Parreira, V. R.; Sharif, S.; Prescott, J. F.

    2006-01-01

    Little is known about immunity to necrotic enteritis (NE) in chickens. A recent study of broiler chickens showed that protection against NE was associated with infection-immunization with virulent but not with avirulent Clostridium perfringens.In the current study, six secreted antigenic proteins unique to virulent C. perfringens that reacted to serum antibodies from immune birds were identified by mass spectrophotometry; three of these proteins are part of the VirR-VirS regulon.

  3. Cellular Uptake of the Clostridium perfringens Binary Iota-Toxin

    Science.gov (United States)

    Blöcker, Dagmar; Behlke, Joachim; Aktories, Klaus; Barth, Holger

    2001-01-01

    The binary iota-toxin is produced by Clostridium perfringens type E strains and consists of two separate proteins, the binding component iota b (98 kDa) and an actin-ADP-ribosylating enzyme component iota a (47 kDa). Iota b binds to the cell surface receptor and mediates the translocation of iota a into the cytosol. Here we studied the cellular uptake of iota-toxin into Vero cells. Bafilomycin A1, but not brefeldin A or nocodazole, inhibited the cytotoxic effects of iota-toxin, indicating that toxin is translocated from an endosomal compartment into the cytoplasm. Acidification (pH ≤ 5.0) of the extracellular medium enabled iota a to directly enter the cytosol in the presence of iota b. Activation by chymotrypsin induced oligomerization of iota b in solution. An average mass of 530 ± 28 kDa for oligomers was determined by analytical ultracentrifugation, indicating heptamer formation. The entry of iota-toxin into polarized CaCo-2 cells was studied by measuring the decrease in transepithelial resistance after toxin treatment. Iota-toxin led to a significant decrease in resistance when it was applied to the basolateral surface of the cells but not following application to the apical surface, indicating a polarized localization of the iota-toxin receptor. PMID:11292715

  4. Toxin genotyping of Clostridium perfringens field strains isolated from healthy and diseased chickens

    Directory of Open Access Journals (Sweden)

    Luca Bano

    2010-01-01

    Full Text Available Clostridium perfringens is well known as the aetiological agent of necrotic enteritis in chicken. Type A and type C are considered the C. perfringens toxin types responsible for this disease. The aim of this study was to determine the presence of genes coding for α, β, ε, ι, β2 and enterotoxin in C. perfringens field strains collected from healthy and diseased chickens. Thirty-seven C. perfringens field strains were toxin typed: all strains resulted to be toxin type A and 3 of these tested positive for the presence of the toxin β2 coding gene. Four isolates showed the cpa gene with the insertion of a group II intron. Our findings confirm the most recent results reported from different countries and the data suggest that the role of C. perfringens type C should be revaluated in the etiopathogenesis of necrotic enteritis.

  5. Antimicrobial susceptibility of Clostridium perfringens isolated from piglets with or without diarrhea in Brazil

    Science.gov (United States)

    Salvarani, Felipe Masiero; Silveira Silva, Rodrigo Otávio; Pires, Prhiscylla Sadanã; da Costa Cruz Júnior, Eduardo Coulaud; Albefaro, Isabella Silva; de Carvalho Guedes, Roberto Maurício; Faria Lobato, Francisco Carlos

    2012-01-01

    The minimum inhibitory concentration (MIC) was determined for 13 antibiotics against Clostridium perfringens isolated from Brazilian piglets. The collection of isolates was performed in June to October 2010. All isolates were susceptible to amoxicillin and ceftiofur, whereas most were resistant to tetracycline and lincomycin. Avilamycin and narasin were more effective against isolates from non-diarrheic than from diarrheic piglets. The other antimicrobials were less active in need of high concentrations to inhibit the growth of the C. perfringens type A. These results suggest the need for further studies evaluating molecular factors related to the antimicrobial resistance of C. perfringens. PMID:24031924

  6. Clostridium perfringens bacteremia caused by choledocholithiasis in the absence of gallbladder stones.

    Science.gov (United States)

    Atia, Antwan; Raiyani, Tejas; Patel, Pranav; Patton, Robert; Young, Mark

    2012-10-21

    A 67-years-old male presented with periumbilical abdominal pain, fever and jaundice. His anaerobic blood culture was positive for clostridium perfringens. Computed tomogram scan of the abdomen and abdominal ultrasound showed normal gallbladder and common bile duct (CBD). Subsequently magnetic resonance cholangiopancreaticogram showed choledocholithiasis. Endoscopic retrograde cholangiopancreaticogramwith sphincterotomy and CBD stone extraction was performed. The patient progressively improved with antibiotic therapy Choledocholithiasis should be considered as a source of clostridium perfringens bacteremia especially in the setting of elevated liver enzymes with cholestatic pattern.

  7. Alpha toxin specific PCR for detection of toxigenic strains of Clostridium perfringens in Poultry

    Directory of Open Access Journals (Sweden)

    Malmarugan Shanmugasamy

    2012-12-01

    Full Text Available Aim : Isolation of clostridium perfirngens from necrotic enteritis cases in poultry and confirmation by alpha toxin specific PCR Materials and methods: Robertson cooked meat medium with Brain Heart Infusion broth was used for isolation of C. perfringens from intestinal contents of necrotic enteritis suspected birds. Positive cultures from perfringens agar were further confirmed by biochemical tests and subjected to alpha toxin specific PCR. Results: Twenty Clostridium perfringens isolates were isolated from intestinal contents of thirty five NE suspected birds. Out of the twenty isolates, fourteen were isolated from commercial broilers of 2 to 6 wk of age and six from commercial layers of 9 to 15 wk of age. Frequency of isolation of C. perfringens was more with Robertson cooked meat medium with BHI broth than thioglycollate broth alone. When positive cultures were streaked on to clostridial agar appreciable luxuriant growths were obtained and the selective streaking of these colonies on perfringens agar with supplements revealed rough and black colonies with sulphate reduction. The isolates produced rough and black colonies with sulphate reduction on perfringens agar, double zone haemolysis on sheep blood agar, stormy clot fermentation on milk medium and opalescence on egg yolk medium. The isolates were found negative for oxidase, catalase, liquefied gelatin, fermented glucose, maltose, lactose and sucrose except mannitol. All the fourteen isolates obtained from commercial broilers proved the alpha toxin producing strains of C. perfringens when they were subjected to alpha toxin specific PCR. Conclusion : This study revealed alpha toxin specific PCR is highly useful for detection of toxigenic strains of Clostridium perfringens in poultry [Vet. World 2012; 5(6.000: 365-368

  8. EGA Protects Mammalian Cells from Clostridium difficile CDT, Clostridium perfringens Iota Toxin and Clostridium botulinum C2 Toxin.

    Science.gov (United States)

    Schnell, Leonie; Mittler, Ann-Katrin; Sadi, Mirko; Popoff, Michel R; Schwan, Carsten; Aktories, Klaus; Mattarei, Andrea; Azarnia Tehran, Domenico; Montecucco, Cesare; Barth, Holger

    2016-04-01

    The pathogenic bacteria Clostridium difficile, Clostridium perfringens and Clostridium botulinum produce the binary actin ADP-ribosylating toxins CDT, iota and C2, respectively. These toxins are composed of a transport component (B) and a separate enzyme component (A). When both components assemble on the surface of mammalian target cells, the B components mediate the entry of the A components via endosomes into the cytosol. Here, the A components ADP-ribosylate G-actin, resulting in depolymerization of F-actin, cell-rounding and eventually death. In the present study, we demonstrate that 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone (EGA), a compound that protects cells from multiple toxins and viruses, also protects different mammalian epithelial cells from all three binary actin ADP-ribosylating toxins. In contrast, EGA did not inhibit the intoxication of cells with Clostridium difficile toxins A and B, indicating a possible different entry route for this toxin. EGA does not affect either the binding of the C2 toxin to the cells surface or the enzyme activity of the A components of CDT, iota and C2, suggesting that this compound interferes with cellular uptake of the toxins. Moreover, for C2 toxin, we demonstrated that EGA inhibits the pH-dependent transport of the A component across cell membranes. EGA is not cytotoxic, and therefore, we propose it as a lead compound for the development of novel pharmacological inhibitors against clostridial binary actin ADP-ribosylating toxins.

  9. EGA Protects Mammalian Cells from Clostridium difficile CDT, Clostridium perfringens Iota Toxin and Clostridium botulinum C2 Toxin

    Science.gov (United States)

    Schnell, Leonie; Mittler, Ann-Katrin; Sadi, Mirko; Popoff, Michel R.; Schwan, Carsten; Aktories, Klaus; Mattarei, Andrea; Tehran, Domenico Azarnia; Montecucco, Cesare; Barth, Holger

    2016-01-01

    The pathogenic bacteria Clostridium difficile, Clostridium perfringens and Clostridium botulinum produce the binary actin ADP-ribosylating toxins CDT, iota and C2, respectively. These toxins are composed of a transport component (B) and a separate enzyme component (A). When both components assemble on the surface of mammalian target cells, the B components mediate the entry of the A components via endosomes into the cytosol. Here, the A components ADP-ribosylate G-actin, resulting in depolymerization of F-actin, cell-rounding and eventually death. In the present study, we demonstrate that 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone (EGA), a compound that protects cells from multiple toxins and viruses, also protects different mammalian epithelial cells from all three binary actin ADP-ribosylating toxins. In contrast, EGA did not inhibit the intoxication of cells with Clostridium difficile toxins A and B, indicating a possible different entry route for this toxin. EGA does not affect either the binding of the C2 toxin to the cells surface or the enzyme activity of the A components of CDT, iota and C2, suggesting that this compound interferes with cellular uptake of the toxins. Moreover, for C2 toxin, we demonstrated that EGA inhibits the pH-dependent transport of the A component across cell membranes. EGA is not cytotoxic, and therefore, we propose it as a lead compound for the development of novel pharmacological inhibitors against clostridial binary actin ADP-ribosylating toxins. PMID:27043629

  10. Thermal inactivation of ileal loop-reactive Clostridium perfringens type A strains in phosphate buffer and beef gravy.

    Science.gov (United States)

    Bradshaw, J G; Peeler, J T; Twedt, R M

    1977-09-01

    The thermal resistance of spore crops produced from each of two ileal loop-reactive strains of Clostridium perfringens type A was determined in two suspending vehicles consisting of 0.067 M (pH 7.0) phosphate buffer and a commercial beef gravy. D115.6 values obtained in buffer and enumerated after pretreatment with sodium ethylenediaminetetraacetate and recovery in plating medium containing lysozyme were two- to threefold greater than those obtained without this treatment. D115.6 values obtained with beef gravy were less than those obtained in buffer with or without lysozyme; however, the D98.9 and D104.4 values were 1.3 to 2 times greater than those obtained in buffer with lysozyme. The z values were within the ranges reported by previous investigators.

  11. A Quantitative Electrochemiluminescence Assay for Clostridium perfringens alpha toxin

    National Research Council Canada - National Science Library

    Merrill, Gerald A; Rivera, Victor R; Neal, Dwayne D; Young, Charles; Poli, Mark A

    2006-01-01

    .... Biotinylated antibodies to C. perfringens alpha toxin bound to streptavidin paramagnetic beads specifically immunoadsorbed soluble sample alpha toxin which subsequently selectively immunoadsorbed ruthenium (Ru...

  12. Bystander Host Cell Killing Effects of Clostridium perfringens Enterotoxin

    Directory of Open Access Journals (Sweden)

    Archana Shrestha

    2016-12-01

    Full Text Available Clostridium perfringens enterotoxin (CPE binds to claudin receptors, e.g., claudin-4, and then forms a pore that triggers cell death. Pure cultures of host cells that do not express claudin receptors, e.g., fibroblasts, are unaffected by pathophysiologically relevant CPE concentrations in vitro. However, both CPE-insensitive and CPE-sensitive host cells are present in vivo. Therefore, this study tested whether CPE treatment might affect fibroblasts when cocultured with CPE-sensitive claudin-4 fibroblast transfectants or Caco-2 cells. Under these conditions, immunofluorescence microscopy detected increased death of fibroblasts. This cytotoxic effect involved release of a toxic factor from the dying CPE-sensitive cells, since it could be reproduced using culture supernatants from CPE-treated sensitive cells. Supernatants from CPE-treated sensitive cells, particularly Caco-2 cells, were found to contain high levels of membrane vesicles, often containing a CPE species. However, most cytotoxic activity remained in those supernatants even after membrane vesicle depletion, and CPE was not detected in fibroblasts treated with supernatants from CPE-treated sensitive cells. Instead, characterization studies suggest that a major cytotoxic factor present in supernatants from CPE-treated sensitive cells may be a 10- to 30-kDa host serine protease or require the action of that host serine protease. Induction of caspase-3-mediated apoptosis was found to be important for triggering release of the cytotoxic factor(s from CPE-treated sensitive host cells. Furthermore, the cytotoxic factor(s in these supernatants was shown to induce a caspase-3-mediated killing of fibroblasts. This bystander killing effect due to release of cytotoxic factors from CPE-treated sensitive cells could contribute to CPE-mediated disease.

  13. Enteric Diseases of Poultry with Special Attention to Clostridium perfringens

    Directory of Open Access Journals (Sweden)

    Hafez Mohamed Hafez

    2011-06-01

    Full Text Available The enteric heath of growing poultry is imperative to success of the production. The basic role of poultry production is turning feed stuffs into meat. Any changes in this turning process, due to mechanical, chemical or biological disturbance of digestive system (enteric disorders is mostly accompanied with high economic losses due to poor performance, increased mortality rates and increased medication costs. The severity of clinical signs and course of the disorders are influenced several factors such as management, nutrition and the involved agent(s. Several pathogens (viruses, bacteria and parasites are incriminated as possible cause of enteric disorders either alone (mono-causal, in synergy with other micro-organisms (multi-causal, or with non-infectious causes such as feed and /or management related factors. In addition, excessive levels of mycotoxins and biogenic amines in feed lead to enteric disorders. Also factors such as high stocking density, poor litter conditions, poor hygiene and high ammonia level and other stressful situation may reduce the resistance of the birds and increases their susceptibility to infections. Under field conditions, however, under filed conditions it is difficult to determine whether the true cause of enteric disorders, is of infectious or non-infectious origin. In recent years and since the ban of use of antimicrobial growth promoters in several countries the incidence of intestinal disorders especially those caused by clostridial infection was drastically increased. The present review described in general the several factors involved in enteric disorders and summarized the available literatures about Clostridium perfringens infection in poultry.

  14. Characterization of Clostridium perfringens isolated from mammals and birds from Guwahati city, India

    Directory of Open Access Journals (Sweden)

    Mafruza S Rahman

    2012-01-01

    Full Text Available Of the 102 samples collected from mammals and birds, both domestic and captive wild, 48 were found to be positive for Clostridium perfringens. Most of the mammal isolates (84.38% appeared to have been collected from clinically affected animals, while 33.33% of the bird samples were from clinically affected and 21.43% from apparently healthy birds infected with C. perfringens. Isolates revealed high sensitivity to ciprofloxacin, enrofloxacin and norfloxacin. Among the isolated C. perfringens, 30 (62.50% showed DNase production. Hemolytic activity was recorded in 14 (24.16% of the isolates and 28 (58.33% showed phospholipase C production. All the phospholipase C positive isolates revealed the presence of cpa gene encoding alpha (α toxin. Of the 102 samples collected from mammals and birds, both domestic and captive wild, 48 were found to be positive for Clostridium perfringens. Most of the mammal isolates (84.38% appeared to have been collected from clinically affected animals, while 33.33% of the bird samples were from clinically affected and 21.43% from apparently healthy birds infected with C. perfringens. Isolates revealed high sensitivity to ciprofloxacin, enrofloxacin and norfloxacin. Among the isolated C. perfringens, 30 (62.50% showed DNase production. Hemolytic activity was recorded in 14 (24.16% of the isolates and 28 (58.33% showed phospholipase C production. All the phospholipase C positive isolates revealed the presence of cpa gene encoding α toxin.

  15. Bacillus subtilis and yeast cell wall improve the intestinal health of broilers challenged by Clostridium perfringens.

    Science.gov (United States)

    Li, Z; Wang, W; Lv, Z; Liu, D; Guo, Y

    2017-12-01

    1. The objective was to investigate the effects of Bacillus subtilis, yeast cell wall (YCW) and their combination on intestinal health of broilers challenged by Clostridium perfringens over a 21-d period. 2. Using a 5 × 2 factorial arrangement of treatments, 800 1-d-old male Cobb 500 broilers were used to study the effects of feed additives (without additive or with zinc bacitracin, B. subtilis, YCW, and the combination of B. subtilis and YCW), pathogen challenge (without or with Clostridium perfringens challenge), and their interactive effects. 3. C. perfringens infection increased intestinal lesions scores, damaged intestinal histomorphology, increased serum endotoxin concentration, cytokine mRNA expression and intestinal population of C. perfringens and Escherichia coli and decreased ileal bifidobacteria numbers. The 4 additives decreased serum endotoxin. Zinc bacitracin tended to decrease cytokine mRNA expression and the intestinal number of C. perfringens and E. coli. B. subtilis, YCW and their combination increased cytokine mRNA expression. B. subtilis and YCW decreased the number of C. perfringens and E. coli in the ileum, and their combination decreased pathogens numbers in the ileum and caecum. 4. In conclusion, B. subtilis, YCW and their combination improved the intestinal health of NE-infected broilers, and could be potential alternatives to antibiotics.

  16. Application of Lactobacillus johnsonii expressing phage endolysin for control of Clostridium perfringens.

    Science.gov (United States)

    Gervasi, T; Lo Curto, R; Minniti, E; Narbad, A; Mayer, M J

    2014-10-01

    Clostridium perfringens is frequently found in food and the environment and produces potent toxins that have a negative impact on both human and animal health and particularly on the poultry industry. Lactobacillus johnsonii FI9785, isolated from the chicken gastrointestinal tract, has been demonstrated to exclude Cl. perfringens in poultry. We have investigated the interaction of wild-type Lact. johnsonii FI9785 or an engineered strain expressing a cell wall-hydrolysing endolysin with Cl. perfringens in vitro, using a batch culture designed to simulate human gastrointestinal tract conditions. Co-culture experiments indicated that acid production by Lact. johnsonii is important in pathogen control. The co-culture of the endolysin-secreting Lact. johnsonii with Cl. perfringens showed that the engineered strain had the potential to control the pathogen, but the ability to reduce Cl. perfringens numbers was not consistent. Results obtained indicate that survival of high numbers of Lact. johnsonii will be essential for effective pathogen control. Significance and impact of the study: The bacterium Lactobacillus johnsonii FI9785 reduces numbers of the pathogen Clostridium perfringens in vitro. Biocontrol was improved by engineering the strain to produce and export a cell wall-hydrolysing endolysin, but good survival of the producer strain is essential. The production of bacteriophage endolysins by commensal bacteria has the potential to improve competitive exclusion of pathogens in the gastrointestinal tract. © 2014 The Society for Applied Microbiology.

  17. Clostridium perfringens and C. difficile in parvovirus-positive dogs.

    Science.gov (United States)

    Silva, Rodrigo Otávio Silveira; Dorella, Fernanda Alves; Figueiredo, Henrique Cesar Pereira; Costa, Érica Azevedo; Pelicia, Vanessa; Ribeiro, Bruna Letícia Devidé; Ribeiro, Marcio Garcia; Paes, Antonio Carlos; Megid, Jane; Lobato, Francisco Carlos Faria

    2017-12-01

    The aim of this study was to investigate Clostridium difficile and Clostridium perfringens in 82 diarrheic dogs positive for canine parvovirus type 2 (CPV). Enterotoxigenic C. perfringens type A was isolated from three (3.6%) dogs. One (1.2%) strain was also positive for NetE- and NetF-encoding genes, which are commonly associated with diarrhea in dogs. Toxigenic C. difficile was isolated from one animal (1.2%), which was also positive for A/B toxins. The present study identified C. difficile and C. perfringens infection in CPV-positive dogs. Further studies are necessary to clarify if clostridial infections may predispose or potentiate CPV-infection in dogs or vice versa. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Clostridium perfringens infection complicating periprosthetic fracture fixation about the hip: successful treatment with early aggressive debridement.

    LENUS (Irish Health Repository)

    Baker, Joseph F

    2012-07-13

    Periprosthetic fracture and infection are both challenges following hip arthroplasty. We report the case of an 87 year old female who underwent open reduction and internal fixation of a periprosthetic femoral fracture. Her post-operative course was complicated by infection with Clostridium perfringens. Early aggressive antibiotic treatment and surgical debridement were successful, and allowed retention of the original components.

  19. Clostridium perfringens bacteremia caused by choledocholithiasis in the absence of gallbladder stones

    OpenAIRE

    Atia, Antwan; Raiyani, Tejas; Patel, Pranav; Patton, Robert; Young, Mark

    2012-01-01

    A 67-years-old male presented with periumbilical abdominal pain, fever and jaundice. His anaerobic blood culture was positive for clostridium perfringens. Computed tomogram scan of the abdomen and abdominal ultrasound showed normal gallbladder and common bile duct (CBD). Subsequently magnetic resonance cholangiopancreaticogram showed choledocholithiasis. Endoscopic retrograde cholangiopancreaticogramwith sphincterotomy and CBD stone extraction was performed. The patient progressively improved...

  20. In vitro Clostridium perfringens and Escherichia coli toxin adsorption of Varium

    Science.gov (United States)

    Enteric disease agents, such as Clostridium perfringens and Escherichia coli, produce detrimental biotoxins that cause significant economic loss annually in the poultry industry. The objective of this study was to determine the in vitro biotoxin adsorption capability of Varium. An enzyme-linked im...

  1. Tolerance of Clostridium perfringens biofilms to disinfectants commonly used in the food industry.

    Science.gov (United States)

    Charlebois, Audrey; Jacques, Mario; Boulianne, Martine; Archambault, Marie

    2017-04-01

    Clostridium perfringens is an opportunistic pathogen that can cause food poisoning in humans and various enterotoxemia in animal species. Recently, it was shown to form mono-species biofilms, a structured community of bacterial cells enclosed in a self-produced extracellular matrix. Biofilms have been associated with tolerance to antibiotics, disinfectants, and physical and environmental stresses. Very little is known about the tolerance of C. perfringens biofilm toward disinfectants. In the present study, susceptibilities of C. perfringens biofilms to five types of commonly used disinfectants on farms and in food processing environments were analysed. In this paper, we show that C. perfringens mono-species biofilms can protect the bacterial cells from the action of potassium monopersulfate, quaternary ammonium chloride, hydrogen peroxide and glutaraldehyde solutions. However, sodium hypochlorite solution was shown to be effective on C. perfringens biofilms. Our investigation of dual-species biofilms of C. perfringens with the addition of Staphylococcus aureus or Escherichia coli demonstrated that overall, the mono-species biofilm of C. perfringens was more tolerant to all disinfectants than the dual-species biofilms. For the anaerobic grown biofilms, the mono-species biofilm of C. perfringens was more tolerant to sodium hypochlorite and quaternary ammonium chloride than the dual-species biofilms of C. perfringens with S. aureus or E. coli. This study demonstrates that C. perfringens biofilm is an effective protection mechanism to disinfectants commonly used on farms and in food processing environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Chitosan inhibits enterotoxigenic Clostridium perfringens type A in growth medium and chicken meat.

    Science.gov (United States)

    Alnoman, Maryam; Udompijitkul, Pathima; Sarker, Mahfuzur R

    2017-06-01

    Clostridium perfringens is a spore-forming bacterium and a major cause of bacterial food-borne illness. In this study, we evaluated the inhibitory effects of chitosan against spore germination, spore outgrowth and vegetative growth of C. perfringens food poisoning (FP) isolates. Chitosan of differing molecular weights inhibited germination of spores of all tested FP isolates in a KCl germinant solution containing 0.1 mg/ml chitosan at pH 4.5. However, higher level (0.25 mg/ml) of chitosan was required to effectively arrest outgrowth of the germinated C. perfringens spores in Tripticase-yeast extract-glucose (TGY) medium. Furthermore, chitosan (1.0 mg/ml) was bacteriostatic against vegetative cells of C. perfringens in TGY medium. Although chitosan showed strong inhibitory activities against C. perfringens in laboratory medium, higher levels (2.0 mg/g) were required to achieve similar inhibition of spores inoculated into chicken meat. In summary, the inhibitory effects of chitosan against C. perfringens FP isolates was concentration dependent, and no major difference was observed when using different molecule weight chitosan as an inhibitor. Our results contribute to a better understanding on the potential application of chitosan in cooked meat products to control C. perfringens-associated disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. The Role of Clostridium Perfringens in the Syndrome of Intestinal Affection in Children and Possibilities of Drug Correction

    Directory of Open Access Journals (Sweden)

    G.O. Lezhenko

    2014-09-01

    Full Text Available The article showed the features of clostridiosis course, caused by Clostridium perfringens, in children of different age groups taking into account the dose of pathogen in feces and pathogenetically grounded possibilities of etiological therapy.

  4. Reproducible Infection Model for Clostridium perfringens in Broiler Chickens

    DEFF Research Database (Denmark)

    Pedersen, Karl; Friis-Holm, Lotte Bjerrum; Heuer, Ole Eske

    2008-01-01

    , 18, 20, and 24 ( Experiment 2). There was no mortality in any of the groups; however, chickens in the groups receiving both coccidial vaccine and C. perfringens developed the subclinical form of necrotic enteritis, demonstrated by focal necroses in the small intestine, whereas chickens in control...... groups or groups receiving only coccidial vaccine or only C. perfringens cultures developed no necroses. The results underline the importance of predisposing factors in the development of necrotic enteritis....

  5. GENOTYPING OF CLOSTRIDIUM PERFRINGENS FROM FRESH WATER FISH AND FISH PICKLES

    Directory of Open Access Journals (Sweden)

    Adarsh Jain

    2012-08-01

    Full Text Available This study aims to evaluate the genotypes of Clostridium perfringens in fish and fish based products from Tamil Nadu and Kerala states of India. A total of 301 samples consisting intestinal contents of freshwater fish (234 from various dams, freshwater lakes, ponds, retail shops and markets and fish pickles (67 obtained from randomly selected retail shops and supermarkets were investigated. Bacterial isolations, identifications and phenotypic characterization of virulence factors were carried out as per standard microbiological procedures. Genotyping of the C. perfringens isolates were done by amplifying four major lethal toxin genes namely- alpha toxin gene (cpa, beta toxin gene (cpb, epsilon toxin gene (etx, iota toxin gene (iA in a Thermal Cycler. Isolates were also screened for the presence of enterotoxin gene (cpe and beta2 toxin gene (cpb2 by single step PCR. Biochemical tests and phenotypic determination of virulence factors tentatively identified 82 (27.24% isolates of C. perfringens. In PCR assay, all 82 (100% isolates harbored cpa toxin genes of C. perfringens, however, 65 (79.26% isolates also carried additional cpb2 toxin genes. None of the isolates were found positive for beta, epsilon, iota and enterotoxin genes. Genotyping of the 82 isolates by PCR revealed that all the isolated bacteria were belonged to C. perfringens type A and both cpa and cpb2 toxin genes were prevalent among the isolates of C. perfringens type A, impending the risk of pathogenicity to human via freshwater fish and fish pickles.

  6. Multidrug resistance in Clostridium perfringens isolated from diarrheal neonatal piglets in Thailand.

    Science.gov (United States)

    Ngamwongsatit, Bhinyada; Tanomsridachchai, Wimonrat; Suthienkul, Orasa; Urairong, Supanee; Navasakuljinda, Wichian; Janvilisri, Tavan

    2016-04-01

    Clostridium perfringens causes diarrhea in neonatal piglets, thereby affecting commercial swine farming. The objective of this study was to determine the prevalence and characterize antimicrobial resistance in C. perfringens isolated from diarrheal neonatal piglets in Thailand. A total of 260 rectal swab samples were collected from 13 farms and were subjected to C. perfringens isolation. A total of 148 samples were PCR-positive for C. perfringens toxin genes, from which 122 were recovered. All isolates were cpb2-encoding C. perfringens type A and enterotoxin gene negative. Most of the isolates were susceptible to ampicillin, bacitracin, chlorotetracycline, doxycycline, and oxytetracycline with MIC50 values ranging from 0.32 to 8 μg/ml. The high resistance rates were observed for ceftiofur, enrofloxacin, erythromycin, lincomycin, and tylosin. Among resistant isolates, 82% were resistant to more than one type of antibiotics. The distinct pattern of multiple drug resistance in C. perfringens was observed in different regions, potentially reflecting the farm specific usage of these agents. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Occurrence of Clostridium perfringens contamination in poultry feed ingredients: Isolation, identification and its antibiotic sensitivity pattern

    Directory of Open Access Journals (Sweden)

    Shanmugasundaram Udhayavel

    2017-09-01

    Full Text Available This work has been undertaken to study the occurrence of Clostridium perfringens contamination in the poultry feed ingredients and find out its in-vitro antibiotic sensitivity pattern to various antimicrobial drugs. Two hundred and ninety-eight poultry feed ingredient samples received at Poultry Disease Diagnosis and Surveillance Laboratory, Namakkal, Tamil Nadu in South India were screened for the presence of C. perfringens. The organisms were isolated in Perfringens agar under anaerobic condition and subjected to standard biochemical tests for confirmation. In vitro antibiogram assay has been carried out to determine the sensitivity pattern of the isolates to various antimicrobial drugs. One hundred and one isolates of C. perfringens were obtained from a total of 298 poultry feed ingredient samples. Overall positivity of 33.89% could be made from the poultry feed ingredients. Highest level of C. perfringens contamination was detected in fish meal followed by bone meal, meat and bone meal and dry fish. Antibiogram assay indicated that the organisms are highly sensitive to gentamicin (100%, chlortetracycline (96.67%, gatifloxacin (93.33%, ciprofloxacin (86.67%, ofloxacin (86.67% and lincomycin (86.67%. All the isolates were resistant to penicillin-G. Feed ingredients rich in animal proteins are the major source of C. perfringens contamination.

  8. Incidence and tracking of Clostridium perfringens through an integrated broiler chicken operation.

    Science.gov (United States)

    Craven, S E; Cox, N A; Bailey, J S; Cosby, D E

    2003-01-01

    Clostridium perfringens has been shown to be widespread in the broiler chicken hatchery, grow-out, and processing operations. In a previous study, ribotypes of certain strains of C. perfringens isolated from processed chicken carcasses were shown to match ribotypes isolated from paper pad lining trays used to transport commercial chicks from the hatchery to the grow-out facility on the farm. These results suggest that C. perfringens contaminating the processed product could originate from facilities in the integrated poultry operation prior to grow out. In this study, samples were collected from the breeder farm, hatchery, previous grow-out flock, during grow out and after processing. In the first trial, C. perfringens was recovered from the breeder farms, the hatchery, previous grow-out flock, grow-out flock at 3 weeks of age, grow-out flock at 5 weeks of age, from processed carcasses, and from the breeder farm after processing in 4%, 30%, 4%, 0%, 2% and 16%, and 4% of the samples, respectively. In the second trial, the incidence of C. perfringens in samples collected from breeder farms, the hatchery, previous grow-out flock, grow-out flock at 3 weeks of age, grow-out flock at 5 weeks of age, and fromprocessed carcasses was 38%, 30%, 32%, 8%, 4%, and 8%, respectively. The genetic relatedness of the isolated strains as determined by ribotyping suggests that C. perfringens may be transmitted between facilities within the integrated broiler chicken operation.

  9. Liver abscess and sepsis caused by Clostridium perfringens and Klebsiella oxytoca

    Directory of Open Access Journals (Sweden)

    Christoph Paasch

    Full Text Available Introduction: Clostridium (C perfringens and Klebsiella (K oxytoca are pathogenous human bacteria. Due to the production of several toxins C. perfringens is virulent by causing i.a. the necrotizing fasciitis, gas gangrene and hepatic abscess. K. oxytoca mostly causes infections of the respiratory and gastrointestinal tract. Presentation of case: We are presenting the case of a male patient at the age of 64, who suffered from nausea and progressive pain in the right upper abdomen. A computer tomography of the abdomen revealed a 7 × 5,6 cm sized entrapped air in liver segment VII. Later the patient developed a multiorgan failure. We then performed an explorative laparotomy. Intraoperatively it became clear that the liver was destructed presenting an open liver abscess (LA cavity of segment VII. The gallbladder was found inflamed. We successfully conducted the consistent debridement of segment VII and removed the gallbladder. Microbiological examination isolated C. perfringens and K. oxytoca. The patient survived undergoing antimicrobial and multimodal sepsis therapy. Discussion: The LA is a severe disease in surgery. In literature an overall mortality of 6–14% is described. Mostly bacterial infections of the biliary tract and the gallbladder are responsible for a LA. Abscesses with sepsis caused by both, C. perfringens and K. oxytoca, are highly perilous but rarely described in literature. Conclusion: When diagnosing an LA caused by C. perfringens an immediate surgical debridement and antimicrobial treatment is mandatory for the patient’s survival. Keywords: Liver abscess, Sepsis, Clostridium perfringens, Klebsiella oxytoca, Gas gangrene

  10. Clostridium perfringens types A and D associated with enterotoxemia in an 18-month-old goat

    Directory of Open Access Journals (Sweden)

    S. Miyashiro

    2007-01-01

    Full Text Available Postmortem examination of a Boer buck that died peracutely revealed bowel and liver diffusely congested and edematous. Kidney was apparently edematous. Clostridium perfringens type A was isolated from bowel and type D from kidney. Microscopic examination revealed large areas of necrosis in the renal cortex and medulla (pulpy kidney disease, hyperemia and centrilobular necrosis of the liver, necrosis of the small-intestine wall, pulmonary edema and congestion, intense hyperemia of the cerebellum, hyperemia and edema of the brain.

  11. [A case of freeze-dried gas gangrene antitoxin for the treatment of Clostridium perfringens sepsis].

    Science.gov (United States)

    Yoshida, Juichiro; Nakamura, Hideki; Yamada, Shinya; Sekoguchi, Satoru; Suzuki, Takahiro; Tomatsuri, Naoya; Sato, Hideki; Okuyama, Yusuke; Kimura, Hiroyuki; Yoshida, Norimasa

    2015-02-01

    A 66-year-old man was admitted to our hospital with high fever. We diagnosed a gas-containing liver abscess and performed percutaneous abscess drainage. However, 15 hours after admission, he developed massive intravascular hemolysis and acidosis. Sepsis due to Clostridium perfringens was suspected and we treated the patient intensively with multidisciplinary approaches, including antibiotics, mechanical ventilation, and renal replacement therapy. Furthermore, we administered freeze-dried gas gangrene antitoxin. Despite intensive care, the patient died 43 hours after admission.

  12. Clostridium perfringens in London, July 2009: two weddings and an outbreak.

    Science.gov (United States)

    Eriksen, J; Zenner, D; Anderson, S R; Grant, K; Kumar, D

    2010-06-24

    Food poisoning outbreaks caused by Clostridium perfringens enterotoxin occur occasionally in Europe but have become less common in recent years. This paper presents the microbiological and epidemiological results of a large C. perfringens outbreak occurring simultaneously at two weddings that used the same caterer. The outbreak involved several London locations and required coordination across multiple agencies. A case-control study (n=134) was carried out to analyse possible associations between the food consumed and becoming ill. Food, environmental and stool samples were tested for common causative agents, including enterotoxigenic C. perfringens. The clinical presentation and the epidemiological findings were compatible with C. perfringens food poisoning and C. perfringens enterotoxin was detected in stool samples from two cases. The case-control study found statistically significant associations between becoming ill and eating either a specific chicken or lamb dish prepared by the same food handler of the implicated catering company. A rapid outbreak investigation with preliminary real-time results and the successful collaboration between the agencies and the caterer led to timely identification and rectification of the failures in the food handling practices.

  13. [Cloning of Clostridium perfringens alpha-toxin gene and extracellular expression in Escherichia coli].

    Science.gov (United States)

    Inoue, Masaharu; Kikuchi, Maho; Komoriya, Tomoe; Watanabe, Kunitomo; Kouno, Hideki

    2007-01-01

    Clostridium perfringens (C. perfringens) is a Gram-positive bacterial pathogen that widely propagets in the soil and the gastrointestinal tract of human and animals. This bacteria causes food poisoning, gas gangrene and other various range of infectious diseases. But there is no standard diagnosis method of C. perfringens. In order to develop a new type of immunoassay for clinical purpose, we studied expression and extracellular secretion of recombinant alpha-toxin having enzyme activity in E. coli expression system. Cloning was carried out after PCR amplification from C. perfringens GAI 94074 which was clinical isolate. Three kinds of fragment were cloned using pET100/D-TOPO vector. These fragments coded for ribosome binding site, signal peptide, and alpha-toxin gene respectively. Recombinant pET100 plasmid transformed into TOP 10 cells and the obtained plasmids were transformed into BL21 (DE3) cells. Then, the transformants were induced expression with IPTG. In conclusion, we successfully cloned, expressed and exteracellular secreted C. perfringens alpha-toxin containing signal peptide. Biologically, the obtained recombinant protein was positive for phospholipase C activity.

  14. A rapid qualitative assay for detection of Clostridium perfringens in canned food products.

    Science.gov (United States)

    Dave, Gayatri Ashwinkumar

    2017-01-01

    Clostridium perfringens (MTCC 1349) is a Gram-positive, anaerobic, endospore forming, and rod-shaped bacterium. This bacterium produces a variety of toxins under strict anaerobic environment. C. perfringens can grow at temperatures ranging between 20°C and 50°C. It is the major causetive agent for gas gangrene, cellulitis, septicemia, necrotic enteritis and food poisoning, which are common toxin induced conditions noted in human and animals. C. perfringens can produce produce four major types of toxins that are used for the classification of strains, classified under type A-E. Across the globe many countries, including the United States, are affected by C. perfringens food poisonings where it is ranked as one of the most common causes of food borne infections. To date, no direct one step assay for the detection of C. perfringens has been developed and only few methods are known for accurate detection of C. perfringens. Long detection and incubation time is the major consideration of these reporter assays. The prensent study proposes a rapid and reliable colorimetric assay for the detection of C. perfringens. In principale, this assay detects the para nitrophenyl (yellow colour end product) liberated due to the hydrolysis of paranitrophenyl phosphetidyl choline (PNPC) through phospholipase C (lecithinase). Constitutive secretion of phospholipase C is a charactristic feature of C. perfringens. This assay detects the presence of the extracellular lecithinse through the PNPC impragnated impregnated probe. The probe is impregnated with peranitrophenyl phosphotidyl choline ester, which is colourless substrate used by lecithinase. The designed assay is specific towards PNPC and detectes very small quantites of lecithinase under conditions used. The reaction is substrate specific, no cross reaction was observed upon incubation with other substrates. In addition, this assay gave negative results with other clostridium strains, no cross reactions were observed with other

  15. Detection of enterotoxigenic Clostridium perfringens in meat samples by using molecular methods.

    Science.gov (United States)

    Kaneko, Ikuko; Miyamoto, Kazuaki; Mimura, Kanako; Yumine, Natsuko; Utsunomiya, Hirotoshi; Akimoto, Shigeru; McClane, Bruce A

    2011-11-01

    To prevent food-borne bacterial diseases and to trace bacterial contamination events to foods, microbial source tracking (MST) methods provide important epidemiological information. To apply molecular methods to MST, it is necessary not only to amplify bacterial cells to detection limit levels but also to prepare DNA with reduced inhibitory compounds and contamination. Isolates carrying the Clostridium perfringens enterotoxin gene (cpe) on the chromosome or a plasmid rank among the most important food-borne pathogens. Previous surveys indicated that cpe-positive C. perfringens isolates are present in only ∼5% of nonoutbreak food samples and then only at low numbers, usually less than 3 cells/g. In this study, four molecular assays for the detection of cpe-positive C. perfringens isolates, i.e., ordinary PCR, nested PCR, real-time PCR, and loop-mediated isothermal amplification (LAMP), were developed and evaluated for their reliability using purified DNA. For use in the artificial contamination of meat samples, DNA templates were prepared by three different commercial DNA preparation kits. The four molecular assays always detected cpe when >10³ cells/g of cpe-positive C. perfringens were present, using any kit. Of three tested commercial DNA preparation kits, the InstaGene matrix kit appeared to be most suitable for the testing of a large number of samples. By using the InstaGene matrix kit, the four molecular assays efficiently detected cpe using DNA prepared from enrichment culture specimens of meat samples contaminated with low numbers of cpe-positive C. perfringens vegetative cells or spores. Overall, the current study developed molecular assay protocols for MST to detect the contamination of foods with low numbers of cells, and at a low frequency, of cpe-positive C. perfringens isolates.

  16. Detection of Enterotoxigenic Clostridium perfringens in Meat Samples by Using Molecular Methods▿

    Science.gov (United States)

    Kaneko, Ikuko; Miyamoto, Kazuaki; Mimura, Kanako; Yumine, Natsuko; Utsunomiya, Hirotoshi; Akimoto, Shigeru; McClane, Bruce A.

    2011-01-01

    To prevent food-borne bacterial diseases and to trace bacterial contamination events to foods, microbial source tracking (MST) methods provide important epidemiological information. To apply molecular methods to MST, it is necessary not only to amplify bacterial cells to detection limit levels but also to prepare DNA with reduced inhibitory compounds and contamination. Isolates carrying the Clostridium perfringens enterotoxin gene (cpe) on the chromosome or a plasmid rank among the most important food-borne pathogens. Previous surveys indicated that cpe-positive C. perfringens isolates are present in only ∼5% of nonoutbreak food samples and then only at low numbers, usually less than 3 cells/g. In this study, four molecular assays for the detection of cpe-positive C. perfringens isolates, i.e., ordinary PCR, nested PCR, real-time PCR, and loop-mediated isothermal amplification (LAMP), were developed and evaluated for their reliability using purified DNA. For use in the artificial contamination of meat samples, DNA templates were prepared by three different commercial DNA preparation kits. The four molecular assays always detected cpe when >103 cells/g of cpe-positive C. perfringens were present, using any kit. Of three tested commercial DNA preparation kits, the InstaGene matrix kit appeared to be most suitable for the testing of a large number of samples. By using the InstaGene matrix kit, the four molecular assays efficiently detected cpe using DNA prepared from enrichment culture specimens of meat samples contaminated with low numbers of cpe-positive C. perfringens vegetative cells or spores. Overall, the current study developed molecular assay protocols for MST to detect the contamination of foods with low numbers of cells, and at a low frequency, of cpe-positive C. perfringens isolates. PMID:21890671

  17. Diversity of Clostridium perfringens isolates from various sources and prevalence of conjugative plasmids.

    Science.gov (United States)

    Park, Miseon; Deck, Joanna; Foley, Steven L; Nayak, Rajesh; Songer, J Glenn; Seibel, Janice R; Khan, Saeed A; Rooney, Alejandro P; Hecht, David W; Rafii, Fatemeh

    2016-04-01

    Clostridium perfringens is an important pathogen, causing food poisoning and other mild to severe infections in humans and animals. Some strains of C. perfringens contain conjugative plasmids, which may carry antimicrobial resistance and toxin genes. We studied genomic and plasmid diversity of 145 C. perfringens type A strains isolated from soils, foods, chickens, clinical samples, and domestic animals (porcine, bovine and canine), from different geographic areas in the United States between 1994 and 2006, using multiple-locus variable-number tandem repeat analysis (MLVA) and/or pulsed-field gel electrophoresis (PFGE). MLVA detected the genetic diversity in a majority of the isolates. PFGE, using SmaI and KspI, confirmed the MLVA results but also detected differences among the strains that could not be differentiated by MLVA. All of the PFGE profiles of the strains were different, except for a few of the epidemiologically related strains, which were identical. The PFGE profiles of strains isolated from the same domestic animal species were clustered more closely with each other than with other strains. However, a variety of C. perfringens strains with distinct genetic backgrounds were found among the clinical isolates. Variation was also observed in the size and number of plasmids in the strains. Primers for the internal fragment of a conjugative tcpH gene of C. perfringens plasmid pCPF4969 amplified identical size fragments from a majority of strains tested; and this gene hybridized to the various-sized plasmids of these strains. The sequences of the PCR-amplified tcpH genes from 12 strains showed diversity among the tcpH genes. Regardless of the sources of the isolates, the genetic diversity of C. perfringens extended to the plasmids carrying conjugative genes. Published by Elsevier Ltd.

  18. Cloning the enterotoxin gene from Clostridium perfringens type A

    OpenAIRE

    Iwanejko, Lesley Ann.

    1991-01-01

    A C. perfringens type A genomic library was constructed in E. coli by banking overlapping 6-10 kbp Hind III fragments of chromosomal DNA from the enterotoxin (CPE) positive strain NCTC 8239 into the pUC derived vector pHG165. The library was screened by colony hybridization with a degenerate 26 bp oligonucleotide probe, derived from the amino acid sequence CPE9_17A. complex mixture of plasmid DNA was isolated from the only hybridization positive clone. A second round of screening picked out a...

  19. Transcriptional Profile during Deoxycholate-Induced Sporulation in a Clostridium perfringens Isolate Causing Foodborne Illness.

    Science.gov (United States)

    Yasugi, Mayo; Okuzaki, Daisuke; Kuwana, Ritsuko; Takamatsu, Hiromu; Fujita, Masaya; Sarker, Mahfuzur R; Miyake, Masami

    2016-05-15

    Clostridium perfringens type A is a common source of foodborne illness (FBI) in humans. Vegetative cells sporulate in the small intestinal tract and produce the major pathogenic factor C. perfringens enterotoxin. Although sporulation plays a critical role in the pathogenesis of FBI, the mechanisms inducing sporulation remain unclear. Bile salts were shown previously to induce sporulation, and we confirmed deoxycholate (DCA)-induced sporulation in C. perfringens strain NCTC8239 cocultured with human intestinal epithelial Caco-2 cells. In the present study, we performed transcriptome analyses of strain NCTC8239 in order to elucidate the mechanism underlying DCA-induced sporulation. Of the 2,761 genes analyzed, 333 were up- or downregulated during DCA-induced sporulation and included genes for cell division, nutrient metabolism, signal transduction, and defense mechanisms. In contrast, the virulence-associated transcriptional regulators (the VirR/VirS system, the agr system, codY, and abrB) were not activated by DCA. DCA markedly increased the expression of signaling molecules controlled by Spo0A, the master regulator of the sporulation process, whereas the expression of spo0A itself was not altered in the presence or absence of DCA. The phosphorylation of Spo0A was enhanced in the presence of DCA. Collectively, these results demonstrated that DCA induced sporulation, at least partially, by facilitating the phosphorylation of Spo0A and activating Spo0A-regulated genes in strain NCTC8239 while altering the expression of various genes. Disease caused by Clostridium perfringens type A consistently ranks among the most common bacterial foodborne illnesses in humans in developed countries. The sporulation of C. perfringens in the small intestinal tract is a key event for its pathogenesis, but the factors and underlying mechanisms by which C. perfringens sporulates in vivo currently remain unclear. Bile salts, major components of bile, which is secreted from the liver for

  20. Toxin genotyping of Clostridium perfringens strains using a polymerase chain reaction protocol

    Directory of Open Access Journals (Sweden)

    Elisabetta Di Giannatale

    2010-03-01

    Full Text Available A polymerase chain reaction protocol consisting of a multiplex to identify the cpa, cpb1, cpetx, cpi genes and a duplex to identify the cpe and cpb2 genes encoding for a, b1, e, i, enterotoxin and b2 toxins, respectively, was applied to DNA extracted from two collections of Clostridium perfringens strains. The first collection involved 19 isolates from rabbits. The second collection of 41 isolates came from routine necropsies. The cpa gene alone, or in association with the cpb2 gene, was detected in all DNA samples examined. The cpa gene, together with cpb2 gene, were detected in seven of the rabbit C. perfringens strains (36.8% and in nine isolates from necropsies (21.9%. The cpa gene was found in 63.2% of rabbit strains and 76.9% of strains from other animal species. In rabbits, the pathological lesions associated with C. perfringens detection were predominantly forms of non-inflammatory enteropathies. In other species, C. perfringens was mainly associated with congestive-haemorrhagic enteropathy, but also with fatal traumatic lesions, degenerative diseases and organs with post-mortem autolysis. No clear correlation was observed between detection of b2 toxin gene and species-specific pathological features.

  1. Occurrence of Beta2 toxigenic Clostridium perfringens isolates with different toxin types in Iran

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    Jabbari, A.R.

    2012-11-01

    Full Text Available Clostridium perfringens is an important cause of enteric diseases in both human and animals. The bacteria produce several toxins which play key roles in the pathogenesis of diseases and are classified into five toxin types, on the basis of the differential production of Alpha, Beta, Epsilon and Iota toxins. In this study a single PCR assay was developed and used for detection of cpb2 gene to identify the Beta2 harboring isolates among different types of C. perfringens isolated from animal enteric diseases in Iran. It was found that cpb2 presents among C. perfringens isolates types A, B, C and D with 54.5% (6/11, 62% (13/21, 42.8% (6/14, 69.25% (9/13, respectively. Totally 34 of 59 (56.7% isolates screened by PCR were cpb2-positive. This is the first report of cpb2 positive isolates of C. perfringens causing enteric diseases of animals in Iran. Further studies to demonstrate the exact role of Beta2 toxin in pathogenesis of the bacterium is suggested.

  2. Incidence of Clostridium perfringens in Broiler Chickens in the Czech Republic

    Directory of Open Access Journals (Sweden)

    I. Svobodová

    2007-01-01

    Full Text Available Clostridium perfringens is a causative agent of human and animal foodborne diseases. It is known as a normal inhabitant of the intestinal tract of chickens as well as a potential pathogen causing necrotic enteritis. The aim of the present study was to detect the incidence of C. perfringens in healthy broiler chickens. From May 2005 to September 2006, 609 samples of caecal content from broilers from 23 intensive poultry farms were analyzed. The samples were cultivated on TSC and blood agar, typical colonies were identified and biochemically confirmed. the total number of positive samples was 112 (18.39%. the samples were processed by the multiplex polymerase chain reaction method (PCR for toxin genotyping. The presence of alpha, beta, beta2 and enterotoxin gene was detected. All C. perfringens isolates were classified as type A, four isolates had the cpb2 gene. In conclusion the prevalence of C. perfringens-positive farms is approximately 74% and the amount ranges about 104 cfu/g of caecal content.

  3. Lipoproteins from Clostridium perfringens and their protective efficacy in mouse model.

    Science.gov (United States)

    Dwivedi, Pratistha; Alam, Syed Imteyaz; Kumar, Om; Kumar, Ravi Bhushan

    2015-08-01

    Clostridium perfringens is an obligately anaerobic rod-shaped bacterium and etiological agent for several diseases in humans and animals. The pathogen has been listed as Validated Biological Agent and warrants development of medical countermeasures. The homologs of some of the lipoproteins identified from various fractions of C. perfringens in our previous studies were observed to be virulence determinants in other pathogenic bacteria. Three putative virulence associated lipoproteins; polysaccharide deacetylase family protein, probable ion-uptake ABC transporter, and a putative lipoprotein of no known function are reported here with respect to their immuno-protective potentials. The three proteins were over expressed and purified to near homogeneity. The lipoproteins were shown to be exposed on the C. perfringens surface and, hence, accessible to antibodies and potentially visible to the host immune system. Immunization of mice with purified recombinant proteins elicited protective immunity against challenge with C. perfringens in mouse gas gangrene model. Distribution and relationship of orthologous proteins across other bacterial select agents especially among the members of Firmicutes, was carried out to look for conserved antigenic determinants. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. A Quantitative Electrochemiluminescence Assay for Clostridium perfringens alpha toxin

    Science.gov (United States)

    2006-08-10

    Doyle, L.R. Beuchat, T.J. Montville (Eds.), Food Microbiology : Fundamentals and Fron- tiers, Second ed., ASM Press, Washington, D.C., 2001, pp. 351...D.E. Lorant, A.E. Bryant, G.A. Zimmerman, T.M. McIn- tyre, D.L. Stevens, S.M. Prescott , Alpha toxin from Clostridium per- fringens induces

  5. Necrotizing Enterocolitis in Preterm Pigs Is Associated with Increased Density of Intestinal Mucosa-Associated Bacteria Including Clostridium perfringens

    DEFF Research Database (Denmark)

    Støy, Ann Cathrine Findal; Mølbak, Lars; Delègue, Camilla Lindholm

    2015-01-01

    correlates with NEC severity in preterm pigs and that in vitro infection with increasing densities of Clostridium perfringens, which has been associated with NEC in preterm infants, would lead to a transcriptional response related to the inflammatory conditions of NEC. Methods: First, we determined...... the density of total bacteria and C. perfringens in the distal small intestinal mucosa of 58 NEC and healthy preterm pigs using quantitative PCR. Next, we analyzed in IPEC-J2 cells the effect of different infection densities of C. perfringens type A on the expression of genes related to intestinal function...

  6. Cloning in Escherichia coli of the enterotoxin gene from Clostridium perfringens type A.

    Science.gov (United States)

    Iwanejko, L A; Routledge, M N; Stewart, G S

    1989-04-01

    A 26 bp DNA probe has been constructed with minimal degeneracy to the protein sequence for Clostridium perfringens enterotoxin. The probe has been hybridized against a 6-10 kb chromosomal bank from C. perfringens 8239, prepared as a HindIII partial digest in pHG165. From this survey a clone has been identified containing a 6.8 kb DNA insert with strong hybridization to the probe. Direct plasmid sequencing has identified a translational reading frame within this clone which correlates with the known protein sequence for the type A enterotoxin. DNA sequences 5' to this open reading frame and containing the putative transcriptional control regions show areas of significant homology with regions upstream from the ATG codon of the tetanus toxin gene.

  7. Identification and Characterization of a New Enterotoxin Produced by Clostridium perfringens Isolated from Food Poisoning Outbreaks.

    Directory of Open Access Journals (Sweden)

    Daisuke Irikura

    Full Text Available There is a strain of Clostridium perfringens, W5052, which does not produce a known enterotoxin. We herein report that the strain W5052 expressed a homologue of the iota-like toxin components sa and sb of C. spiroforme, named Clostridium perfringens iota-like enterotoxin, CPILE-a and CPILE-b, respectively, based on the results of a genome sequencing analysis and a systematic protein screening. In the nicotinamide glyco-hydrolase (NADase assay the hydrolysis activity was dose-dependently increased by the concentration of rCPILE-a, as judged by the mass spectrometry analysis. In addition, the actin monomer of the lysates of Vero and L929 cells were radiolabeled in the presence of [32P]NAD and rCPILE-a. These findings indicated that CPILE-a possesses ADP-ribosylation activity. The culture supernatant of W5052 facilitated the rounding and killing of Vero and L929 cells, but the rCPILE-a or a non-proteolyzed rCPILE-b did not. However, a trypsin-treated rCPILE-b did. Moreover, a mixture of rCPILE-a and the trypsin-treated rCPILE-b enhanced the cell rounding and killing activities, compared with that induced by the trypsin-treated rCPILE-b alone. The injection of the mixture of rCPILE-a and the trypsin-treated rCPILE-b into an ileum loop of rabbits evoked the swelling of the loop and accumulation of the fluid dose-dependently, suggesting that CPILE possesses enterotoxic activity. The evidence presented in this communication will facilitate the epidemiological, etiological, and toxicological studies of C. perfringens food poisoning, and also stimulate studies on the transfer of the toxins' gene(s among the Genus Clostridium.

  8. Molecular analysis of the interaction between Clostridium perfringens Enterotoxin and Claudins

    OpenAIRE

    Protze, Jonas

    2015-01-01

    Claudins are essential constituents of Tight Junctions (TJs) and responsible for maintenance of these cell-cell contacts. Binding of Clostridium perfringens Enterotoxin’s C-terminal domain (cCPE) to the extracellular loop 2 (EZS2) of claudins, especially Cld3, Cld4 and Cld6-Cld9 causes a reversible opening of TJs. Thus, a structure-function analysis of this system is relevant for biomedical application, since cCPE could be used to enhance paracellular drug uptake. Furthermore cCPE respectivel...

  9. CodY Promotes Sporulation and Enterotoxin Production by Clostridium perfringens Type A Strain SM101.

    Science.gov (United States)

    Li, Jihong; Freedman, John C; Evans, Daniel R; McClane, Bruce A

    2017-03-01

    Clostridium perfringens type D strains cause enterotoxemia and enteritis in livestock via epsilon toxin production. In type D strain CN3718, CodY was previously shown to increase the level of epsilon toxin production and repress sporulation. C. perfringens type A strains producing C. perfringens enterotoxin (CPE) cause human food poisoning and antibiotic-associated diarrhea. Sporulation is critical for C. perfringens type A food poisoning since spores contribute to transmission and resistance in the harsh food environment and sporulation is essential for CPE production. Therefore, the current study asked whether CodY also regulates sporulation and CPE production in SM101, a derivative of C. perfringens type A food-poisoning strain NCTC8798. An isogenic codY -null mutant of SM101 showed decreased levels of spore formation, along with lower levels of CPE production. A complemented strain recovered wild-type levels of both sporulation and CPE production. When this result was coupled with the earlier results obtained with CN3718, it became apparent that CodY regulation of sporulation varies among different C. perfringens strains. Results from quantitative reverse transcriptase PCR analysis clearly demonstrated that, during sporulation, codY transcript levels remained high in SM101 but rapidly declined in CN3718. In addition, abrB gene expression patterns varied significantly between codY -null mutants of SM101 and CN3718. Compared to the levels in their wild-type parents, the level of abrB gene expression decreased in the CN3718 codY -null mutant strain but significantly increased in the SM101 codY -null mutant strain, demonstrating CodY-dependent regulation differences in abrB expression between these two strains. This difference appears to be important since overexpression of the abrB gene in SM101 reduced the levels of sporulation and enterotoxin production, supporting the involvement of AbrB repression in regulating C. perfringens sporulation. Copyright © 2017

  10. Isolation, molecular characterization and prevalence of Clostridium perfringens in sheep and goats of Kashmir Himalayas, India

    Directory of Open Access Journals (Sweden)

    Salik Nazki

    2017-12-01

    Full Text Available Aim: The study was conducted to report the occurrence of the Clostridium perfringens in sheep and goats of the Kashmir valley for the 1st time and to characterize them molecularly with respect to toxin genes to determine the prevalence of the various toxinotypes. Materials and Methods: A total of 177 samples (152 from sheep and 25 from goats collected from healthy, diarrheic animals, and morbid material of animals suspected to have died of enterotoxaemia were screened for C. perfringens toxinotypes. The presumptive positive isolates were confirmed using 16S rRNA gene-based polymerase chain reaction (PCR. All the confirmed isolates were screened for six toxin genes, namely; cpa, cpb, etx, cpi, cpb2, and cpe using a multiplex PCR. Results: The PCR amplification of 16S rRNA gene revealed that out of 177 samples collected, 125 (70.62% were found positive for C. perfringens, of which 110 (72.36% were from sheep and 15 (60% were from goats. The highest prevalence of C. perfringens toxinotype D was observed in lambs (56.16% and kids (46.16% followed by 3.84% in adult sheep while it was absent in samples obtained from adult goats. The multiplex PCR revealed that 67 (60.90% isolates from sheep and 8 (53.33% isolates from goats belonged to toxinotype A, while 43 (39.09% isolates from sheep and 7 (46.66% isolates from goats were detected as toxinotype D. None of the isolates was found to be toxinotype B, C, or E. All the C. perfringens toxinotype A isolates from sheep were negative for both cpb2 and cpe genes, however, 27.90% toxinotype D isolates from sheep carried cpb2 gene, and 6.97% possessed cpe gene. In contrast, 12.50% C. perfringens toxinotype A isolates from goats harbored cpb2 and cpe genes while 14.28% isolates belonging to toxinotype D carried cpb2 and cpe genes, respectively. Conclusion: The high prevalence of C. perfringens was observed, even in day-old lambs. The toxinotypes A and D are prevalent in both sheep and goats. The severity of

  11. Alphitobius diaperinus spp como veiculador de Clostridium perfringens em granjas avícolas do interior paulista - Brasil Alphitobius diaperinus spp as a vector of Clostridium perfringens in broiler houses in the state of São Paulo - Brazil

    Directory of Open Access Journals (Sweden)

    Juliano Vittori

    2007-06-01

    Full Text Available O besouro Alphitobius diaperinus spp (cascudinho é visto como uma importante praga da avicultura mundial. Por suas características comportamentais e hábitos biológicos que dificultam seu controle, é considerado um vetor de agentes patogênicos. O objetivo desta pesquisa foi investigar o cascudinho como possível vetor de Clostridium perfringens em granjas avícolas industriais, localizadas em diferentes regiões do interior Paulista. Através de métodos bacteriológicos convencionais, em 40 amostras analisadas, foram encontradas contagens significativas de Clostridium perfringens em todas elas. A partir dos resultados obtidos, pôde-se demonstrar o potencial deste inseto como vetor do agente responsável pela enterite necrótica.The Alphitobius diaperinus spp (lesser mealworm is considered an important world poultry plague. Due to its behavior characteristics and biological habits that make its control difficult it is considered a vector of pathogenic agents. The objective of this research was to investigate the little mealworm as possible vector of Clostridium perfringens in broiler houses, located in different parts of the state of São Paulo. Through conventional bacteriological methods, 40 samples of little mealworm collected were analyzed. Clostridium perfringens was found in all of the samples and the potential of this insect as vector of the necrotic enteritis was demonstrated.

  12. Bayesian modeling of Clostridium perfringens growth in beef-in-sauce products.

    Science.gov (United States)

    Jaloustre, S; Cornu, M; Morelli, E; Noël, V; Delignette-Muller, M L

    2011-04-01

    Models on Clostridium perfringens growth which have been published to date have all been deterministic. A probabilistic model describing growth under non-isothermal conditions was thus proposed for predicting C. perfringens growth in beef-in-sauce products cooked and distributed in a French hospital. Model parameters were estimated from different types of data from various studies. A Bayesian approach was proposed to model the overall uncertainty regarding parameters and potential variability on the 'work to be done' (h(0)) during the germination, outgrowth and lag phase. Three models which differed according to their description of this parameter h(0) were tested. The model with inter-curve variability on h(0) was found to be the best one, on the basis of goodness-of-fit assessment and validation with literature data on results obtained under non-isothermal conditions. This model was used in two-dimensional Monte Carlo simulations to predict C. perfringens growth throughout the preparation of beef-in-sauce products, using temperature profiles recorded in a hospital kitchen. The median predicted growth was 7.8×10(-2) log(10) cfu·g(-1) (95% credibility interval [2.4×10(-2), 0.8]) despite the fact that for more than 50% of the registered temperature profiles cooling steps were longer than those required by French regulations. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Mechanisms of Action and Cell Death Associated with Clostridium perfringens Toxins

    Directory of Open Access Journals (Sweden)

    Mauricio A. Navarro

    2018-05-01

    Full Text Available Clostridium perfringens uses its large arsenal of protein toxins to produce histotoxic, neurologic and intestinal infections in humans and animals. The major toxins involved in diseases are alpha (CPA, beta (CPB, epsilon (ETX, iota (ITX, enterotoxin (CPE, and necrotic B-like (NetB toxins. CPA is the main virulence factor involved in gas gangrene in humans, whereas its role in animal diseases is limited and controversial. CPB is responsible for necrotizing enteritis and enterotoxemia, mostly in neonatal individuals of many animal species, including humans. ETX is the main toxin involved in enterotoxemia of sheep and goats. ITX has been implicated in cases of enteritis in rabbits and other animal species; however, its specific role in causing disease has not been proved. CPE is responsible for human food-poisoning and non-foodborne C. perfringens-mediated diarrhea. NetB is the cause of necrotic enteritis in chickens. In most cases, host–toxin interaction starts on the plasma membrane of target cells via specific receptors, resulting in the activation of intracellular pathways with a variety of effects, commonly including cell death. In general, the molecular mechanisms of cell death associated with C. perfringens toxins involve features of apoptosis, necrosis and/or necroptosis.

  14. Effects of Clostridium perfringens iota toxin in the small intestine of mice.

    Science.gov (United States)

    Redondo, Leandro M; Redondo, Enzo A; Dailoff, Gabriela C; Leiva, Carlos L; Díaz-Carrasco, Juan M; Bruzzone, Octavio A; Cangelosi, Adriana; Geoghegan, Patricia; Fernandez-Miyakawa, Mariano E

    2017-12-01

    Iota toxin is a binary toxin solely produced by Clostridium perfringens type E strains, and is structurally related to CDT from C. difficile and CST from C. spiroforme. As type E causes hemorrhagic enteritis in cattle, it is usually assumed that associated diseases are mediated by iota toxin, although evidence in this regard has not been provided. In the present report, iota toxin intestinal effects were evaluated in vivo using a mouse model. Histological damage was observed in ileal loops treated with purified iota toxin after 4 h of incubation. Luminal iota toxin induced fluid accumulation in the small intestine in a dose dependent manner, as determined by the enteropooling and the intestinal loop assays. None of these changes were observed in the large intestine. These results suggest that C. perfringens iota toxin alters intestinal permeability, predominantly by inducing necrosis and degenerative changes in the mucosal epithelium of the small intestine, as well as changes in intestinal motility. The obtained results suggest a central role for iota toxin in the pathogenesis of C. perfringens type E hemorrhagic enteritis, and contribute to remark the importance of clostridial binary toxins in digestive diseases. Published by Elsevier Ltd.

  15. Recombinant Alpha, Beta, and Epsilon Toxins of Clostridium perfringens: Production Strategies and Applications as Veterinary Vaccines

    Directory of Open Access Journals (Sweden)

    Marcos Roberto A. Ferreira

    2016-11-01

    Full Text Available Clostridium perfringens is a spore-forming, commensal, ubiquitous bacterium that is present in the gastrointestinal tract of healthy humans and animals. This bacterium produces up to 18 toxins. The species is classified into five toxinotypes (A–E according to the toxins that the bacterium produces: alpha, beta, epsilon, or iota. Each of these toxinotypes is associated with myriad different, frequently fatal, illnesses that affect a range of farm animals and humans. Alpha, beta, and epsilon toxins are the main causes of disease. Vaccinations that generate neutralizing antibodies are the most common prophylactic measures that are currently in use. These vaccines consist of toxoids that are obtained from C. perfringens cultures. Recombinant vaccines offer several advantages over conventional toxoids, especially in terms of the production process. As such, they are steadily gaining ground as a promising vaccination solution. This review discusses the main strategies that are currently used to produce recombinant vaccines containing alpha, beta, and epsilon toxins of C. perfringens, as well as the potential application of these molecules as vaccines for mammalian livestock animals.

  16. Antibiotic resistance of Clostridium perfringens isolates from broiler chickens in Egypt.

    Science.gov (United States)

    Osman, K M; Elhariri, M

    2013-12-01

    The use of antibiotic feed additives in broiler chickens results in a high prevalence of resistance among their enteric bacteria, with a consequent emergence of antibiotic resistance in zoonotic enteropathogens. Despite growing concerns about the emergence of antibiotic-resistant strains, which show varying prevalences in different geographic regions, little work has been done to investigate this issue in the Middle East. This study provides insight into one of the world's most common and financially crippling poultry diseases, necrotic enteritis caused by Clostridium perfringens. The study was designed to determine the prevalence of antibiotic resistance in C. perfringens isolates from clinical cases of necrotic enteritis in broiler chickens in Egypt. A total of 125 isolates were obtained from broiler flocks in 35 chicken coops on 17 farms and were tested using the disc diffusion method. All 125 isolates were resistant to gentamicin, streptomycin, oxolinic acid, lincomycin, erythromycin and spiramycin. The prevalence of resistance to other antibiotics was also high: rifampicin (34%), chloramphenicol (46%), spectinomycin (50%), tylosin-fosfomycin (52%), ciprofloxacin (58%), norfloxacin (67%), oxytetracycline (71%), flumequine (78%), enrofloxacin (82%), neomycin (93%), colistin (94%), pefloxacin (94%), doxycycline (98%) and trimethoprim-sulfamethoxazole (98%). It is recommended that C. perfringens infections in Egypt should be treated with antibiotics for which resistant isolates are rare at present; namely, amoxicillin, ampicillin, cephradine, fosfomycin and florfenicol.

  17. Characterization of a unique class C acid phosphatase from Clostridium perfringens.

    Science.gov (United States)

    Reilly, Thomas J; Chance, Deborah L; Calcutt, Michael J; Tanner, John J; Felts, Richard L; Waller, Stephen C; Henzl, Michael T; Mawhinney, Thomas P; Ganjam, Irene K; Fales, William H

    2009-06-01

    Clostridium perfringens is a gram-positive anaerobe and a pathogen of medical importance. The detection of acid phosphatase activity is a powerful diagnostic indicator of the presence of C. perfringens among anaerobic isolates; however, characterization of the enzyme has not previously been reported. Provided here are details of the characterization of a soluble recombinant form of this cell-associated enzyme. The denatured enzyme was approximately 31 kDa and a homodimer in solution. It catalyzed the hydrolysis of several substrates, including para-nitrophenyl phosphate, 4-methylumbelliferyl phosphate, and 3' and 5' nucleoside monophosphates at pH 6. Calculated K(m)s ranged from 0.2 to 0.6 mM with maximum velocity ranging from 0.8 to 1.6 micromol of P(i)/s/mg. Activity was enhanced in the presence of some divalent cations but diminished in the presence of others. Wild-type enzyme was detected in all clinical C. perfringens isolates tested and found to be cell associated. The described enzyme belongs to nonspecific acid phosphatase class C but is devoid of lipid modification commonly attributed to this class.

  18. Beta Lactamase Producing Clostridium perfringens Bacteremia in an Elderly Man with Acute Pancreatitis

    Directory of Open Access Journals (Sweden)

    Rashmi Mishra

    2016-01-01

    Full Text Available Clostridium perfringens bacteremia is associated with adverse outcomes. Known risk factors include chronic kidney disease, malignancy, diabetes mellitus, and gastrointestinal disease. We present a 74-year-old man admitted with confusion, vomiting, and abdominal pain. Exam revealed tachycardia, hypotension, lethargy, distended abdomen, and cold extremities. He required intubation and aggressive resuscitation for septic shock. Laboratory data showed leukocytosis, metabolic acidosis, acute kidney injury, and elevated lipase. CT scan of abdomen revealed acute pancreatitis and small bowel ileus. He was started on vancomycin and piperacillin-tazobactam. Initial blood cultures were positive for C. perfringens on day five. Metronidazole and clindamycin were added to the regimen. Repeat CT (day 7 revealed pancreatic necrosis. The patient developed profound circulatory shock requiring multiple vasopressors, renal failure requiring dialysis, and bacteremia with vancomycin-resistant enterococci. Hemodynamic instability precluded surgical intervention and he succumbed to multiorgan failure. Interestingly, our isolate was beta lactamase producing. We review the epidemiology, risk factors, presentation, and management of C. perfringens bacteremia. This case indicates a need for high clinical suspicion for clostridial sepsis and that extended spectrum beta lactam antibiotic coverage may be inadequate and should be supplemented with use of clindamycin or metronidazole if culture is positive, until sensitivities are known.

  19. Antimicrobial susceptibility of Clostridium perfringens isolated from domestic and wild animal species in Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Augusto de Oliveira Júnior

    2016-02-01

    Full Text Available Clostridium perfringens is a microorganism commonly found in the microbiota of humans and animals and a potential cause of enteric, muscle or nervous diseases. The treatment of these diseases is based on antimicrobial therapy and it is extremely important to know the antimicrobial susceptibility profile of the strains present in the region. The aim of this study was to evaluate the antimicrobial susceptibility of C. perfringens isolated from domestic and wild animals in Brazil against seven different antimicrobials. Forty-one strains from the stool samples of cattle (n = 12, buffalo (n = 2, goat (n = 3, dogs (n = 12 and wild carnivores (n = 12 were examined. The minimum inhibitory concentration was determined by the agar dilution method using Brucella agar supplemented with 5% of sheep blood, 0.1% of vitamin K, 0.1% of hemin and concentrations ranging from 0,25 to 256,0 mg L-1 of the following antibiotics: erythromycin, florfenicol, metronidazole, oxytetracycline, penicillin, tylosin, and vancomycin. All C. perfringens strains were susceptible to florfenicol, metronidazole, penicillin and vancomycin. Two strains (4.9% were resistant to erythromycin and tylosin, while five (12.2% were resistant to oxytetracycline, one of which (2.4% from an ocelot.

  20. Toxinotyping and antimicrobial susceptibility of enterotoxigenic Clostridium perfringens isolates from mutton, beef and chicken meat.

    Science.gov (United States)

    Khan, Madiha; Nazir, Jawad; Anjum, Aftab Ahmad; Ahmad, Mansur-Ud-Din; Nawaz, Muhammad; Shabbir, Muhammad Zubair

    2015-08-01

    A total of 300 meat samples comprising mutton, beef, and chicken meat (n = 100) collected from either local butcher shops or large meat outlets situated at various areas of Lahore City located in Punjab province of Pakistan were tested for the isolation of Clostridium perfringens. Prevalence of the organism was highest in the chicken (6 %) followed by mutton (5 %) and beef (1 %). Contamination level was high (10/150) in the samples collected from local butcher shops in comparison to the samples collected from large meat outlets (2/150). All of the raw meat samples were negative for the presence of alpha, beta and epsilon toxins of C. perfringens as detected through ELISA. Out of a total number of 12 isolates only half were capable of producing enterotoxins when cultured in trypticase glucose yeast (TGY) broth. Toxinotyping of the isolates showed that 3 were of type A while one each of the remaining three belonged to type B, C, and D. Antibiotic susceptibility testing of the toxin producing isolates revealed that C. perfringens were susceptible to chloramphenicol, ciprofloxacin, metronidazole, and ceftriaxone. All of the other drugs were relatively less effective with a least activity of amoxicillin against the isolates.

  1. The mycotoxin deoxynivalenol predisposes for the development of Clostridium perfringens-induced necrotic enteritis in broiler chickens.

    Science.gov (United States)

    Antonissen, Gunther; Van Immerseel, Filip; Pasmans, Frank; Ducatelle, Richard; Haesebrouck, Freddy; Timbermont, Leen; Verlinden, Marc; Janssens, Geert Paul Jules; Eeckhaut, Venessa; Eeckhout, Mia; De Saeger, Sarah; Hessenberger, Sabine; Martel, An; Croubels, Siska

    2014-01-01

    Both mycotoxin contamination of feed and Clostridium perfringens-induced necrotic enteritis have an increasing global economic impact on poultry production. Especially the Fusarium mycotoxin deoxynivalenol (DON) is a common feed contaminant. This study aimed at examining the predisposing effect of DON on the development of necrotic enteritis in broiler chickens. An experimental Clostridium perfringens infection study revealed that DON, at a contamination level of 3,000 to 4,000 µg/kg feed, increased the percentage of birds with subclinical necrotic enteritis from 20±2.6% to 47±3.0% (Peffect on in vitro growth, alpha toxin production and netB toxin transcription of Clostridium perfringens. In conclusion, feed contamination with DON at concentrations below the European maximum guidance level of 5,000 µg/kg feed, is a predisposing factor for the development of necrotic enteritis in broilers. These results are associated with a negative effect of DON on the intestinal barrier function and increased intestinal protein availability, which may stimulate growth and toxin production of Clostridium perfringens.

  2. Human alpha-defensin-1 protects cells from intoxication with Clostridium perfringens iota toxin.

    Science.gov (United States)

    Fischer, Stephan; Popoff, Michel R; Barth, Holger

    2018-03-01

    Iota toxin is produced by Clostridium perfringens type E strains and associated with diarrhea in cattle and lambs. This binary protein toxin comprises the enzyme component iota a (Ia), which ADP-ribosylates G-actin, and the separate transport component iota b (Ib), which delivers Ia into the cytosol of target cells. Ib binds to cell receptors and forms biologically active toxin complexes with Ia, which cause rounding of adherent cells due to the destruction of the actin cytoskeleton. Here, we report that the human peptide α-defensin-1 protects cultured cells including human colon cells from intoxication with iota toxin. In contrast, the related ß-defensin-1 had no effect, indicating a specific mode of action. The α-defensin-1 did not inhibit ADP-ribosylation of actin by Ia in vitro. Pretreatment of Ib with α-defensin-1 prior to addition of Ia prevented intoxication. Additionally, α-defensin-1 protected cells from cytotoxic effects mediated by Ib in the absence of Ia, implicating that α-defensin-1 interacts with Ib to prevent the formation of biologically active iota toxin on cells. In conclusion, the findings contribute to a better understanding of the functions of α-defensin-1 and suggest that this human peptide might be an attractive starting point to develop novel pharmacological options to treat/prevent diseases associated with iota toxin-producing Clostridium perfringens strains.

  3. Detection of Clostridium perfringens in yearling lamb meat (barbacoa), head, and gut tacos from public markets in Mexico City.

    Science.gov (United States)

    Natividad-Bonifacio, Iván; Vázquez-Quiñones, Carlos R; Rodas-Suárez, Oscar R; Fernández, Francisco J; Rodríguez-Solis, Esteban; Quiñones-Ramírez, Elsa Irma; Vázquez-Salinas, Carlos

    2010-06-01

    No reports on the incidence of Clostridium perfringens in popularly-consumed food from Mexico City have been published; neither are there any reports that have analyzed food consumed in popular markets and less established restaurants. Therefore, this study is aimed at providing data to evaluate the relevance of C. perfringens as an etiologic agent of food-borne diseases. Of the 650 analyzed samples, 106 (16.3%) were positive for C. perfringens; 6.4% (16/250) isolates were from barbacoa, 19% (38/200) from head, and 13% (52/200) from gut tacos. The presence of C. perfringens in these popular-consumed foods demonstrates its relevance as an etiologic agent of food-borne diseases, and confirms the great sanitary risk involved in their consumption. These results may serve as a basis for the Mexican sanitary authorities to control the microbiological quality of street-made foods.

  4. Nitrate salts suppress sporulation and production of enterotoxin in Clostridium perfringens strain NCTC8239.

    Science.gov (United States)

    Yasugi, Mayo; Otsuka, Keisuke; Miyake, Masami

    2016-10-01

    Clostridium perfringens type A is a common source of food-borne illness in humans. Ingested vegetative cells sporulate in the small intestinal tract and in the process produce C. perfringens enterotoxin (CPE). Although sporulation plays a critical role in the pathogenesis of food-borne illness, the molecules triggering/inhibiting sporulation are still largely unknown. It has previously been reported by our group that sporulation is induced in C. perfringens strain NCTC8239 co-cultured with Caco-2 cells in Dulbecco's Modified Eagle Medium (DMEM). In contrast, an equivalent amount of spores was not observed when bacteria were co-cultured in Roswell Park Memorial Institute-1640 medium (RPMI). In the present study it was found that, when these two media are mixed, RPMI inhibits sporulation and CPE production induced in DMEM. When a component of RPMI was added to DMEM, it was found that calcium nitrate (Ca[NO 3 ] 2 ) significantly inhibits sporulation and CPE production. The number of spores increased when Ca(NO 3 ) 2 -deficient RPMI was used. The other nitrate salts significantly suppressed sporulation, whereas the calcium salts used did not. qPCR revealed that nitrate salts increased expression of bacterial nitrate/nitrite reductase. Furthermore, it was found that nitrite and nitric oxide suppress sporulation. In the sporulation stages, Ca(NO 3 ) 2 down-regulated the genes controlled by Spo0A, a master regulator of sporulation, but not spo0A itself. Collectively, these results indicate that nitrate salts suppress sporulation and CPE production by down-regulating Spo0A-regulated genes in C. perfringens strain NCTC8239. Nitrate reduction may be associated with inhibition of sporulation. © 2016 The Societies and John Wiley & Sons Australia, Ltd.

  5. Structural and biochemical analyses of a Clostridium perfringens sortase D transpeptidase

    Energy Technology Data Exchange (ETDEWEB)

    Suryadinata, Randy, E-mail: randy.suryadinata@csiro.au; Seabrook, Shane A.; Adams, Timothy E.; Nuttall, Stewart D.; Peat, Thomas S., E-mail: randy.suryadinata@csiro.au [Commonwealth Scientific and Industrial Research Organisation, 343 Royal Parade, Parkville, Victoria 3052 (Australia)

    2015-06-30

    The structure of C. perfringens sortase D was determined at 1.99 Å resolution. Comparative biochemical and structural analyses revealed that this transpeptidase may represent a new subclass of the sortase D family. The assembly and anchorage of various pathogenic proteins on the surface of Gram-positive bacteria is mediated by the sortase family of enzymes. These cysteine transpeptidases catalyze a unique sorting signal motif located at the C-terminus of their target substrate and promote the covalent attachment of these proteins onto an amino nucleophile located on another protein or on the bacterial cell wall. Each of the six distinct classes of sortases displays a unique biological role, with sequential activation of multiple sortases often observed in many Gram-positive bacteria to decorate their peptidoglycans. Less is known about the members of the class D family of sortases (SrtD), but they have a suggested role in spore formation in an oxygen-limiting environment. Here, the crystal structure of the SrtD enzyme from Clostridium perfringens was determined at 1.99 Å resolution. Comparative analysis of the C. perfringens SrtD structure reveals the typical eight-stranded β-barrel fold observed in all other known sortases, along with the conserved catalytic triad consisting of cysteine, histidine and arginine residues. Biochemical approaches further reveal the specifics of the SrtD catalytic activity in vitro, with a significant preference for the LPQTGS sorting motif. Additionally, the catalytic activity of SrtD is most efficient at 316 K and can be further improved in the presence of magnesium cations. Since C. perfringens spores are heat-resistant and lead to foodborne illnesses, characterization of the spore-promoting sortase SrtD may lead to the development of new antimicrobial agents.

  6. Synergistic effect of embryo vaccination with Eimeria profilin and Clostridium perfringens NetB proteins on inducing protective immunity against necrotic enteritis in broiler chickens

    Science.gov (United States)

    The effects of embryo vaccination with Eimeria profilin plus Clostridium perfringens NetB toxin proteins in combination with the Montanide IMS-OVO adjuvant on the chicken immune response to necrotic enteritis were investigated using an E. maxima/C. perfringens co-infection model. Eighteen-day-old br...

  7. Evaluating the performance of a new model for predicting the growth of Clostridium perfringens in cooked, uncured meat and poultry products under isothermal, heating, and dynamically cooling conditions

    Science.gov (United States)

    Clostridium perfringens Type A is a significant public health threat and may germinate, outgrow, and multiply during cooling of cooked meats. This study evaluates a new C. perfringens growth model in IPMP Dynamic Prediction using the same criteria and cooling data in Mohr and others (2015), but inc...

  8. Expression of a Clostridium perfringens genome-encoded putative N-acetylmuramoyl-L-alanine amidase as a potential antimicrobial to control the bacterium

    Science.gov (United States)

    Clostridium perfringens is a Gram-positive, spore-forming anaerobic bacterium that plays a substantial role in non-foodborne human, animal and avian diseases as well as human foodborne disease. Previously discovered C. perfringens bacteriophage lytic enzyme amino acid sequences were utilized to iden...

  9. Mastitis in dairy buffalo and cattle in Egypt due to Clostridium perfringens: prevalence, incidence, risk factors and costs.

    Science.gov (United States)

    Osman, K M; El-Enbaawy, M I; Ezzeldeen, N A; Hussein, H M G

    2009-12-01

    Although Clostridium perfringens is recognised as an important cause of clostridial enteric diseases, there is only limited knowledge about the association of particular C. perfringens toxinotypes (types A to E) with mastitis in domestic animals. In this study, mastitis was detected in 213/623 (34.12%) and 8/83 (9.64%) of the quarter milk samples collected from cases of clinical mastitis in cows and buffalo, respectively. The micro-organism was isolated in an incidence of 16/357 (4.48%) of milk samples from cows and 1/25 (4.0%) of samples from buffalo. Infection in one quarter was the most typical situation found (83% in cows and 87% in buffalo). Clostridium perfringens infection was also correlated to the season, with the highest proportion of isolates being found during spring (10.71%) and winter (7.07%). Using the classical toxin neutralisation typing method, 17 strains, isolated from cow and buffalo milk, were identified as C. perfringens type A, and selected for molecular analysis. Polymerase chain reaction detected the oecpa gene while the P/cpb and e/etx genes went undetected. The authors believe that C. perfringens has the potential to produce disease on its own or to predispose the udder to disease caused by major mastitis and environmental pathogens.

  10. Growth potential of Clostridium perfringens from spores in acidified beef, pork, and poultry products during chilling.

    Science.gov (United States)

    Juneja, Vijay K; Baker, David A; Thippareddi, H; Snyder, O Peter; Mohr, Tim B

    2013-01-01

    The ability of Clostridium perfringens to germinate and grow in acidified ground beef as well as in 10 commercially prepared acidified beef, pork, and poultry products was assessed. The pH of ground beef was adjusted with organic vinegar to achieve various pH values between 5.0 and 5.6; the pH of the commercial products ranged from 4.74 to 6.35. Products were inoculated with a three-strain cocktail of C. perfringens spores to achieve ca. 2-log (low) or 4-log (high) inoculum levels, vacuum packaged, and cooled exponentially from 54.4 to 7.2°C for 6, 9, 12, 15, 18, or 21 h to simulate abusive cooling; the U.S. Department of Agriculture, Food Safety and Inspection Service (USDA-FSIS) recommends a cooling time of 6.5 h. Total germinated C. perfringens populations were determined after plating on tryptose-sulfite-cycloserine agar and incubating the plates anaerobically at 37°C for 48 h. In addition, C. perfringens growth from spores was assessed at an isothermal temperature of 44°C. Growth from spores was inhibited in ground beef with a pH of 5.5 or below, even during extended cooling from 54.4 to 7.2°C in 21 h. In ground beef with a pH of 5.6, the growth was >1 log after 18 h of cooling from 54.4 to 7.2°C. However, 15 h of cooling controlled the growth to product with a pH ranging from 4.74 to 5.17, both during exponential abusive cooling periods of up to 21 h and during storage for 21 h at 44°C. While product cooled exponentially from 54.4 to 7.2°C in 15 h or less, the pH 6.35 product supported growth, even after 6 h of cooling from 54.4 to 7.2°C. These challenge tests demonstrate that adjustment of ground beef to pH of 5.5 or less and of barbeque products to pH of 5.63 or less inhibits C. perfringens spore germination and outgrowth during extended cooling periods from 54.4 to 7.2°C up to 15 h. Therefore, safe cooling periods for products with homogeneous, lower pHs can be substantially longer.

  11. Mucin gene mRNA levels in broilers challenged with eimeria and/or Clostridium perfringens.

    Science.gov (United States)

    Kitessa, Soressa M; Nattrass, Gregory S; Forder, Rebecca E A; McGrice, Hayley A; Wu, Shu-Biao; Hughes, Robert J

    2014-09-01

    The effects of Eimeria (EM) and Clostridium perfringens (CP) challenges on the mRNA levels of genes involved in mucin (Muc) synthesis (Muc2, Muc5ac, Muc13, and trefoil family factor-2 [TFF2]), inflammation (tumor necrosis factor alpha [TNF-alpha] and interleukin-18 [IL-18]), and metabolic processes (cluster of differentiation [CD]36) in the jejunum of broilers were investigated. Two parallel experiments involving 1) EM challenge and 2) EM and CP challenges were conducted. The first experiment was a 2 X 2 study with 12 birds per treatment (N = 48) involving fishmeal substitution (25%) in the diet (FM) and EM challenge. The treatments were: Control (FM-, EM-), Fishmeal (FM+, EM-), EM challenge (FM-, EM+), and fishmeal substitution and EM challenge (FM+, EM+). The second experiment was a 2 X 2 X 2 experiment with six birds per treatment (N = 48) involving fishmeal (FM-, FM+), Eimeria (EM-, EM+), and C perfringens (CP-, CP+). In both arms of the study, male broilers were given a starter diet for the whole period of 16 days, except those assigned to FM+, where 25% of the starter ration was replaced with fishmeal from days 8 to 14. EM inoculation was performed on day 9 and CP inoculation on days 14 and 15. The EM challenge birds were euthanatized for sampling on day 13; postmortem examination and sampling for the Eimeria plus C perfringens challenge arm of the study were on day 16. In the Eimeria challenge arm of the study, fishmeal supplementation significantly suppressed the mRNA levels of TNF-alpha, TFF2, and IL-18 pre-CP inoculation but simultaneously increased the levels of Muc13 and CD36 mRNAs. Birds challenged with Eimeria exhibited increased mRNA levels of Muc13, Muc5ac, TNF-alpha, and IL-18. In the Eimeria and C. perfringens challenge arm, birds exposed to EM challenge exhibited significantly lower mRNA levels of Muc2 and CD36. The mRNA levels of CD36 were also significantly suppressed by CP challenge. Our results showed that the transcription of mucin synthesis

  12. Sequence variation in the alpha-toxin encoding plc gene of Clostridium perfringens strains isolated from diseased and healthy chickens

    DEFF Research Database (Denmark)

    Abildgaard, L; Engberg, RM; Pedersen, Karl

    2009-01-01

    The aim of the present study was to analyse the genetic diversity of the alpha-toxin encoding plc gene and the variation in a-toxin production of Clostridium perfringens type A strains isolated from presumably healthy chickens and chickens suffering from either necrotic enteritis (NE) or cholangio......-hepatitis. The a-toxin encoding plc genes from 60 different pulsed-field gel electrophoresis (PFGE) types (strains) of C perfringens were sequenced and translated in silico to amino acid sequences and the a-toxin production was investigated in batch cultures of 45 of the strains using an enzyme...

  13. Effect of tannins on the in vitro growth of Clostridium perfringens.

    Science.gov (United States)

    Elizondo, Ana M; Mercado, Elsa C; Rabinovitz, Bettina C; Fernandez-Miyakawa, Mariano E

    2010-10-26

    Vegetable tannins are water-soluble polyphenolic compounds of varying molecular weights that occur abundantly in nature. The diet of many free-ranging wild animals contains significant amounts of tannins. Also, commercial tannins are used in animal industry as food additives to improve animal performance. In order to further determine the capacity of tannins to inhibit the development of intestinal diseases produced by Clostridium pefringens, we evaluated here the effect of tannins from quebracho, chestnut or combinations of both on C. perfringens and their toxins. The C. perfringens (types A, B, C, D and E) growth obtained from the intestine of healthy and diseased animals was reduced in a dose-dependent manner in the presence of quebracho tannins, chestnut tannins, combinations of both or a commercial formula based in these tannins. Although the minimal inhibitory concentration of both tannins varied between isolates, no statistically significant differences were observed between isolates from healthy or sick animals. Comparative analysis showed that the concentrations of quebracho tannin inhibiting the growth of C. perfringens were higher than chestnut tannin. In fact, antibacterial effect of quebracho tannin was increased up to 20 times with the addition of 25% of chestnut tannin and 85 times with 75% of chestnut tannin. Antibacterial activity of the commercial product was up to ~50 times higher than quebracho tannin alone. Quebracho tannin showed partial bactericidal activity, whereas chestnut tannin activity was stronger. Both tannins were able to reduce the alpha toxin lecithinase activity and epsilon toxin cytotoxicity in MDCK cells. These results suggest that tannin-supplemented diet could be useful to prevent some clostridial diseases. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Claudins Overexpression in Ovarian Cancer: Potential Targets for Clostridium Perfringens Enterotoxin (CPE Based Diagnosis and Therapy

    Directory of Open Access Journals (Sweden)

    Diana P. English

    2013-05-01

    Full Text Available Claudins are a family of tight junction proteins regulating paracellular permeability and cell polarity with different patterns of expression in benign and malignant human tissues. There are approximately 27 members of the claudin family identified to date with varying cell and tissue-specific expression. Claudins-3, -4 and -7 represent the most highly differentially expressed claudins in ovarian cancer. While their exact role in ovarian tumors is still being elucidated, these proteins are thought to be critical for ovarian cancer cell invasion/dissemination and resistance to chemotherapy. Claudin-3 and claudin-4 are the natural receptors for the Clostridium perfringens enterotoxin (CPE, a potent cytolytic toxin. These surface proteins may therefore represent attractive targets for the detection and treatment of chemotherapy-resistant ovarian cancer and other aggressive solid tumors overexpressing claudin-3 and -4 using CPE-based theranostic agents.

  15. Antimicrobial activities of six essential oils commonly used as condiments in Brazil against Clostridium perfringens

    Directory of Open Access Journals (Sweden)

    Marcela Radaelli

    2016-06-01

    Full Text Available Abstract Despite recent advances in food production technology, food-borne diseases (FBD remain a challenging public health concern. In several countries, including Brazil, Clostridium perfringens is among the five main causative agents of food-borne diseases. The present study determines antimicrobial activities of essential oils of six condiments commonly used in Brazil, viz., Ocimum basilicum L. (basil, Rosmarinus officinalis L. (rosemary, Origanum majorana L. (marjoram, Mentha × piperita L. var. Piperita (peppermint, Thymus vulgaris L. (thyme and Pimpinella anisum L. (anise against C. perfringens strain A. Chemical compositions of the oils were determined by GC–MS (gas chromatography–mass spectrometry. The identities of the isolated compounds were established from the respective Kováts indices, and a comparison of mass spectral data was made with those reported earlier. The antibacterial activity was assessed from minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC using the microdilution method. Minimum inhibitory concentration values were 1.25 mg mL-1 for thyme, 5.0 mg mL-1 for basil and marjoram, and 10 mg mL-1 for rosemary, peppermint and anise. All oils showed bactericidal activity at their minimum inhibitory concentration, except anise oil, which was only bacteriostatic. The use of essential oils from these common spices might serve as an alternative to the use of chemical preservatives in the control and inactivation of pathogens in commercially produced food systems.

  16. Antimicrobial activities of six essential oils commonly used as condiments in Brazil against Clostridium perfringens.

    Science.gov (United States)

    Radaelli, Marcela; da Silva, Bárbara Parraga; Weidlich, Luciana; Hoehne, Lucélia; Flach, Adriana; da Costa, Luiz Antonio Mendonça Alves; Ethur, Eduardo Miranda

    2016-01-01

    Despite recent advances in food production technology, food-borne diseases (FBD) remain a challenging public health concern. In several countries, including Brazil, Clostridium perfringens is among the five main causative agents of food-borne diseases. The present study determines antimicrobial activities of essential oils of six condiments commonly used in Brazil, viz., Ocimum basilicum L. (basil), Rosmarinus officinalis L. (rosemary), Origanum majorana L. (marjoram), Mentha × piperita L. var. Piperita (peppermint), Thymus vulgaris L. (thyme) and Pimpinella anisum L. (anise) against C. perfringens strain A. Chemical compositions of the oils were determined by GC-MS (gas chromatography-mass spectrometry). The identities of the isolated compounds were established from the respective Kováts indices, and a comparison of mass spectral data was made with those reported earlier. The antibacterial activity was assessed from minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the microdilution method. Minimum inhibitory concentration values were 1.25mgmL(-1) for thyme, 5.0mgmL(-1) for basil and marjoram, and 10mgmL(-1) for rosemary, peppermint and anise. All oils showed bactericidal activity at their minimum inhibitory concentration, except anise oil, which was only bacteriostatic. The use of essential oils from these common spices might serve as an alternative to the use of chemical preservatives in the control and inactivation of pathogens in commercially produced food systems. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  17. NetB, a new toxin that is associated with avian necrotic enteritis caused by Clostridium perfringens.

    Directory of Open Access Journals (Sweden)

    Anthony L Keyburn

    2008-02-01

    Full Text Available For over 30 years a phospholipase C enzyme called alpha-toxin was thought to be the key virulence factor in necrotic enteritis caused by Clostridium perfringens. However, using a gene knockout mutant we have recently shown that alpha-toxin is not essential for pathogenesis. We have now discovered a key virulence determinant. A novel toxin (NetB was identified in a C. perfringens strain isolated from a chicken suffering from necrotic enteritis (NE. The toxin displayed limited amino acid sequence similarity to several pore forming toxins including beta-toxin from C. perfringens (38% identity and alpha-toxin from Staphylococcus aureus (31% identity. NetB was only identified in C. perfringens type A strains isolated from chickens suffering NE. Both purified native NetB and recombinant NetB displayed cytotoxic activity against the chicken leghorn male hepatoma cell line LMH; inducing cell rounding and lysis. To determine the role of NetB in NE a netB mutant of a virulent C. perfringens chicken isolate was constructed by homologous recombination, and its virulence assessed in a chicken disease model. The netB mutant was unable to cause disease whereas the wild-type parent strain and the netB mutant complemented with a wild-type netB gene caused significant levels of NE. These data show unequivocally that in this isolate a functional NetB toxin is critical for the ability of C. perfringens to cause NE in chickens. This novel toxin is the first definitive virulence factor to be identified in avian C. perfringens strains capable of causing NE. Furthermore, the netB mutant is the first rationally attenuated strain obtained in an NE-causing isolate of C. perfringens; as such it has considerable vaccine potential.

  18. Primeiro relato no Brasil de mastite necrótica bovina por Clostridium perfringens tipo A First report in Brazil of bovine necrotic mastitis due to Clostridium perfringens type A

    Directory of Open Access Journals (Sweden)

    Luciana Aramuni Gonçalves

    2006-08-01

    Full Text Available Relata-se o primeiro caso no Brasil de mastite bovina por Clostridium perfringens tipo A. O quadro clínico caracterizou-se por necrose da papila mamária e porção ventral do quarto afetado. O agente foi isolado em cultura pura e identificado como tipo A por PCR a partir do leite do quarto mamário afetado.This report describes a case of bovine mastitis due to Clostridium perfringens type A for first time in Brazil. The unical case showed necrosis of papilla mammary and ventral portion of the affected quarter. The microorganism was isolated in pure culture and identified as type A by PCR from milk of the affected mammary quarter.

  19. Produção e caracterização de anticorpos monoclonais contra toxina épsilon de Clostridium perfringens Tipo D Production and characterization of monoclonal antibodies against Clostridium perfringens Type D epsilon toxin

    Directory of Open Access Journals (Sweden)

    Theonys Diógenes Freitas

    2009-02-01

    Full Text Available Clostridium perfringens tipo D é o agente etiológico da enterotoxemia em ruminantes, causada pela toxina épsilon e caracterizada por edema cardíaco, pulmonar, renal e cerebral. Anticorpos monoclonais contra toxina épsilon de C. perfringens tipo D foram produzidos a partir da fusão da linhagen de mieloma P3-X63-Ag8 653 com células do baço de camundongos Balb/c imunizados com o toxóide épsilon. Seis linhagens de híbridos secretores de anticorpos monoclonais das classes e IgM e IgG foram estabelecidas.Clostridium perfringens type D is the aetiological agent of enterotoxemia in ruminants. The disease is caused by epsilon toxin characterized by cardiac, pulmonary, kidney and brain edema. Monoclonal antibodies were produced by using myeloma cell line P3-X63-Ag8 653 fused with spleen cells from Balb/c mice, immunized with epsilon toxoid of C. perfringens type D. Six hybrids were established secreting monoclonal antibodies of the IgM class and IgG3 subclass.

  20. Disruption in the cecal microbiota of chickens challenged with Clostridium perfringens and other factors was alleviated by Bacillus licheniformis supplementation.

    Science.gov (United States)

    Lin, Yicen; Xu, Shuai; Zeng, Dong; Ni, Xueqin; Zhou, Mengjia; Zeng, Yan; Wang, Hesong; Zhou, Yi; Zhu, Hui; Pan, Kangcheng; Li, Guangyao

    2017-01-01

    Clostridium perfringens can induce necrotic enteritis of chickens, which causes large economic losses every year. Bacillus licheniformis, a probiotic, can inhibit the growth of pathogenic bacteria such as Clostridium perfringens, thereby improving the health status of chickens. However, from a microbial ecology perspective, the mechanisms by which alterations to the gut microbiota improve health remain unknown. In this study, we used Illumina MiSeq sequencing to investigate the cecal microbiota of a negative control group (NC), a C. perfringens and Eimeria challenge group with fishmeal supplementation (PC), a group supplemented with fishmeal and infected with coccidia (FC), and group PC with B. licheniformis supplementation (BL). We found that the health status of C. perfringens-challenged chickens was compromised, and that B. licheniformis improved the growth of the chickens challenged with pathogens. Microbial diversity analysis and taxonomic profiling of groups NC, PC, and FC revealed a disturbed cecal microflora of the birds with C. perfringens. We also characterized the microbiota of the chickens in the BL group using several methods. Principal coordinate analysis demonstrated that, compared with group PC, the bacterial community structure of group BL was more similar to that of group NC. Linear discriminant analysis with effect size revealed less differentially represented bacterial taxa between groups BL and NC than between groups PC and NC. In addition, groups BL and NC appeared to have similar overrepresented microbial taxa (such as Bacteroides, Helicobacter, Megamonas, and Akkermansia) compared with group PC. Finally, a phylogenetic investigation of communities by reconstruction of unobserved states analysis indicated that large differences existed between group PC and groups NC and BL. In conclusion, pre-treatment with B. licheniformis reduced the disturbance of the cecal microbiome induced by challenge with C. perfringens and other factors in broiler

  1. Clostridium perfringens removal in different stages in a Drinking Water Treatments plant; Eliminacion de Clostidium perfringens en diversas etapas de una estacion de tratamiento de aguas potables

    Energy Technology Data Exchange (ETDEWEB)

    Ormad, M. P.; Lanao, M.; Goni, P.; Ibarz, C.; Ovelleiro, J. L.

    2008-07-01

    The purpose of this research is to evaluate the effectiveness of different stages, which take part in the conventional treatments used in the drinking water treatment plants in Spain, in the removal of a microbiological indicator of faecal pollution, Clostridium perfringens. The stages studied are pre oxidation with chlorine and ozone, chemical precipitation, adsorption with activated coal and filtration sand. The pre oxidation, either with sodium hypochlorite or with ozone, gets final recounts below the detection limit with the conditions studied (> 8 log). In the rest of stages, the removal is minimal, achieving 1,32 logarithmic units at best case. (Author) 6 refs.

  2. The impact of various browse feeds with different tannin content on the fecal shedding of Clostridium perfringens in West African dwarf sheep.

    Science.gov (United States)

    Aschfalk, A; Müller, W; Drochner, W

    2000-01-01

    In 1994 and 1995 leaves from eight browse feeds, containing tannins in different amounts (BF), were fed to West African Dwarf Sheep in Benin to evaluate their impact on Clostridium perfringens in the intestinal tract. An inhibitory impact of various BF on the growth of C. perfringens was assessed in in-vitro assays before, and thus a potential use of these leaves as a preventive diet against C. perfringens enterotoxemia in small ruminants was assumed. Surprisingly, an inhibitory impact of the BF on the shedding of C. perfringens in the feces of West African Dwarf Sheep could not be shown in seven of the eight BF examined. However, the pattern of inhibition of unlike C. perfringens toxovars may differ and a selective inhibitory impact of the BF Dialium guineense on C. perfringens toxovar D may be assumed.

  3. Predicting outgrowth and inactivation of Clostridium perfringens in meat products during low temperature long time heat treatment

    DEFF Research Database (Denmark)

    Duan, Zhi; Hansen, Terese Holst; Hansen, Tina Beck

    2016-01-01

    With low temperature long time (LTLT) cooking it can take hours for meat to reach a final core temperature above 53 °C and germination followed by growth of Clostridium perfringens is a concern. Available and new growth data in meats including 154 lag times (tlag), 224 maximum specific growth rates...... (μmax) and 25 maximum population densities (Nmax) were used to developed a model to predict growth of C. perfringens during the coming-up time of LTLT cooking. New data were generate in 26 challenge tests with chicken (pH 6.8) and pork (pH 5.6) at two different slowly increasing temperature (SIT...... the SIT profiles. Similar results were found for non-heated and heated spores in chicken, whereas in pork C. perfringens 790-94 increased less than 1 log CFU/g. At 53 °C C. perfringens 790-94 was log-linearly inactivated. Observed and predicted concentrations of C. perfringens, at the time when 53 °C (log...

  4. Comparative transcriptome analysis by RNAseq of necrotic enteritis Clostridium perfringens during in vivo colonization and in vitro conditions.

    Science.gov (United States)

    Parreira, Valeria R; Russell, Kay; Athanasiadou, Spiridoula; Prescott, John F

    2016-08-12

    Necrotic enteritis (NE) caused by netB-positive type A Clostridium perfringens is an important bacterial disease of poultry. Through its complex regulatory system, C. perfringens orchestrates the expression of a collection of toxins and extracellular enzymes that are crucial for the development of the disease; environmental conditions play an important role in their regulation. In this study, and for the first time, global transcriptomic analysis was performed on ligated intestinal loops in chickens colonized with a netB-positive C. perfringens strain, as well as the same strain propagated in vitro under various nutritional and environmental conditions. Analysis of the respective pathogen transcriptomes revealed up to 673 genes that were significantly expressed in vivo. Gene expression profiles in vivo were most similar to those of C. perfringens grown in nutritionally-deprived conditions. Taken together, our results suggest a bacterial transcriptome responses to the early stages of adaptation, and colonization of, the chicken intestine. Our work also reveals how netB-positive C. perfringens reacts to different environmental conditions including those in the chicken intestine.

  5. Mode of action of plectasin-derived peptides against gas gangrene-associated Clostridium perfringens type A.

    Directory of Open Access Journals (Sweden)

    Xueling Zheng

    Full Text Available NZ2114 and MP1102 are novel plectasin-derived peptides with potent activity against Gram-positive bacteria. The antibacterial characteristics and mechanism of NZ2114 and MP1102 against gas gangrene-associated Clostridium perfringens were studied for the first time. The minimal inhibitory concentration and minimal bactericidal concentration of NZ2114 and MP1102 against resistant C. perfringens type A strain CVCC 46 were 0.91 μM. Based on the fractional inhibitory concentration index (FICI result, an additive or synergic effect was observed between NZ2114 (FICI = 0.5~0.75 or MP1102 (FICI = 0.375~1.0 and antibiotics. The flow cytometry, scanning and transmission electron microscopy analysis showed that both NZ2114 and MP1102 induced obviously membrane damage, such as the leakage of cellular materials, partial disappearance of the cell membrane and membrane peeling, as well as retracting cytoplasm and ghost cell. The gel retardation and circular dichroism (CD detection showed that NZ2114 and MP1102 could bind to C. perfringens genomic DNA and change the DNA conformation. Moreover, NZ2114 also interfered with the double helix and unwind the genomic DNA. The cell cycle analysis showed that C. perfringens CVCC 46 cells exposed to NZ2114 and MP1102 were arrested at the phase I. These data indicated that both NZ2114 and MP1102 have potential as new antimicrobial agents for gas gangrene infection resulting from resistant C. perfringens.

  6. Effects of Bile Acids and Nisin on the Production of Enterotoxin by Clostridium perfringens in a Nutrient-Rich Medium

    Directory of Open Access Journals (Sweden)

    Miseon Park

    2018-01-01

    Full Text Available Clostridium perfringens is the second most common cause of bacterial foodborne illness in the United States, with nearly a million cases each year. C. perfringens enterotoxin (CPE, produced during sporulation, damages intestinal epithelial cells by pore formation, which results in watery diarrhea. The effects of low concentrations of nisin and bile acids on sporulation and toxin production were investigated in C. perfringens SM101, which carries an enterotoxin gene on the chromosome, in a nutrient-rich medium. Bile acids and nisin increased production of enterotoxin in cultures; bile acids had the highest effect. Both compounds stimulated the transcription of enterotoxin and sporulation-related genes and production of spores during the early growth phase. They also delayed spore outgrowth and nisin was more inhibitory. Bile acids and nisin enhanced enterotoxin production in some but not all other C. perfringens isolates tested. Low concentrations of bile acids and nisin may act as a stress signal for the initiation of sporulation and the early transcription of sporulation-related genes in some strains of C. perfringens, which may result in increased strain-specific production of enterotoxin in those strains. This is the first report showing that nisin and bile acids stimulated the transcription of enterotoxin and sporulation-related genes in a nutrient-rich bacterial culture medium.

  7. Effects of Bile Acids and Nisin on the Production of Enterotoxin by Clostridium perfringens in a Nutrient-Rich Medium.

    Science.gov (United States)

    Park, Miseon; Rafii, Fatemeh

    2018-01-01

    Clostridium perfringens is the second most common cause of bacterial foodborne illness in the United States, with nearly a million cases each year. C. perfringens enterotoxin (CPE), produced during sporulation, damages intestinal epithelial cells by pore formation, which results in watery diarrhea. The effects of low concentrations of nisin and bile acids on sporulation and toxin production were investigated in C. perfringens SM101, which carries an enterotoxin gene on the chromosome, in a nutrient-rich medium. Bile acids and nisin increased production of enterotoxin in cultures; bile acids had the highest effect. Both compounds stimulated the transcription of enterotoxin and sporulation-related genes and production of spores during the early growth phase. They also delayed spore outgrowth and nisin was more inhibitory. Bile acids and nisin enhanced enterotoxin production in some but not all other C. perfringens isolates tested. Low concentrations of bile acids and nisin may act as a stress signal for the initiation of sporulation and the early transcription of sporulation-related genes in some strains of C. perfringens , which may result in increased strain-specific production of enterotoxin in those strains. This is the first report showing that nisin and bile acids stimulated the transcription of enterotoxin and sporulation-related genes in a nutrient-rich bacterial culture medium.

  8. Inactivation of Clostridium perfringens spores adhered onto stainless steel surface by agents used in a clean-in-place procedure.

    Science.gov (United States)

    Alzubeidi, Yasmeen S; Udompijitkul, Pathima; Talukdar, Prabhat K; Sarker, Mahfuzur R

    2018-07-20

    Enterotoxigenic Clostridium perfringens, a leading foodborne pathogen can be cross-contaminated from food processing stainless steel (SS) surfaces to the finished food products. This is mostly due to the high resistance of C. perfringens spores adhered onto SS surfaces to various disinfectants commonly used in food industries. In this study, we aimed to investigate the survivability and adherence of C. perfringens spores onto SS surfaces and then validate the effectiveness of a simulated Clean-in-Place (CIP) regime on inactivation of spores adhered onto SS surfaces. Our results demonstrated that, 1) C. perfringens spores adhered firmly onto SS surfaces and survived for at-least 48 h, unlike their vegetative cells who died within 30 min, after aerobic incubation at refrigerated and ambient temperatures; 2) Spores exhibited higher levels of hydrophobicity than vegetative cells, suggesting a correlation between cell surface hydrophobicity and adhesion to solid surfaces; 3) Intact spores were more hydrophobic than the decoated spores, suggesting a positive role of spore coat components on spores' hydrophobicity and thus adhesion onto SS surfaces; and finally 4) The CIP regime (NaOH + HNO 3 ) successfully inactivated C. perfringens spores adhered onto SS surfaces, and most of the effect of CIP regime appeared to be due to the NaOH. Collectively, our current findings may well contribute towards developing a strategy to control cross-contamination of C. perfringens spores into food products, which should help reducing the risk of C. perfringens-associated food poisoning outbreaks. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Effect of dietary mannan oligosaccharide from Saccharomyces cerevisiae on live performance of broilers under Clostridium perfringens challenge

    Directory of Open Access Journals (Sweden)

    Alaeldein M. Abudabos

    2013-04-01

    Full Text Available A 30-day broiler cage trial was conducted to evaluate the effect of dietary mannan oligosaccharide (MOS from one commercial product (SAF-Mannan on growth parameters, gut health and control pathogen colonization of broilers under Clostridium perfringens (C. perfringens challenge. One hundred, 0-day old male Ross 308 broilers were allocated in 4 experimental treatments for 30 days. The four dietary treatments were T1, standard broiler basal diets without any medication as a control (+CONT; T2, basal diets as in T1 plus C. perfringens challenge (-CONT; T3, enramycin 0.1 g/kg of feed plus C. perfringens challenge (ENRA; T4, SAF-Mannan at 0.5 g/kg in starter and finisher diets plus C. perfringens challenge (SAF. Overall, feed conversion ratio (FCR and body weight gain (BWG in treatments ENRA and SAF were significantly better (P<0.01 than the –CONT treatment, whereas treatment +CONT was intermediate and not different from SAF. Feed intake (FI was not influenced by treatment. SAF-Mannan supplementation was able to lower the ileal C. perfringens count as compared to all other treatments (P<0.05. The changes in C. perfringens count appear in parallel to observed improvement in the cumulative FCR.  The results from this study clearly indicated that SAF-Mannan could act as a replacement for antimicrobial growth promoters in broilers (AGPs. SAF-Mannan level of 0.05% was enough to achieve a response competitive with that of the antibiotic.

  10. Differential responses of cecal microbiota to fishmeal, Eimeria and Clostridium perfringens in a necrotic enteritis challenge model in chickens.

    Directory of Open Access Journals (Sweden)

    Dragana Stanley

    Full Text Available Clostridium perfringens causes enteric diseases in animals and humans. In poultry, avian-specific C. perfringens strains cause necrotic enteritis, an economically significant poultry disease that costs the global industry over $2 billion annually in losses and control measures. With removal of antibiotic growth promoters in some countries this disease appears to be on the rise. In experimental conditions used to study disease pathogenesis and potential control measures, reproduction of the disease relies on the use of predisposing factors such as Eimeria infection and the use of high protein diets, indicating complex mechanisms involved in the onset of necrotic enteritis. The mechanisms by which the predisposing factors contribute to disease progression are not well understood but it has been suggested that they may cause perturbations in the microbiota within the gastrointestinal tract. We inspected changes in cecal microbiota and short chain fatty acids (SCFA induced by Eimeria and fishmeal, in birds challenged or not challenged with C. perfringens. C. perfringens challenge in the absence of predisposing factors did not cause significant changes in either the alpha or beta diversity of the microbiota nor in concentrations of SCFA. Moreover, there was no C. perfringens detected in the cecal microbiota 2 days post-challenge without the presence of predisposing factors. In contrast, both fishmeal and Eimeria caused significant changes in microbiota, seen in both alpha and beta diversity and also enabled C. perfringens to establish itself post challenge. Eimeria had its strongest influence on intestinal microbiota and SCFA when combined with fishmeal. Out of 6 SCFAs measured, including butyric acid, none were significantly influenced by C. perfringens, but their levels were strongly modified following the use of both predisposing factors. There was little overlap in the changes caused following Eimeria and fishmeal treatments, possibly indicating

  11. Assessment of Clostridium perfringens spore response to high hydrostatic pressure and heat with nisin.

    Science.gov (United States)

    Gao, Yulong; Qiu, Weifen; Wu, Ding; Fu, Qiang

    2011-08-01

    The elimination of spores from low-acid foods presents food-processing and food-safety challenges to high-pressure processing (HPP) developers as bacterial spores are extremely resistant to pressure. Therefore, the effects of pressure (400-800 MPa), temperature (35-95 °C), and nisin (0-496 IU/mL) on the inactivation of Clostridium perfringens AS 64701 spores at various pressure-holding times (7.5-17.5 min) were explored. A second-order polynomal equation for HPP- and nisin-induced inactivation of C. perfringens spores was constructed with response surface methodology. Experiment results showed that the experimental values were shown to be significantly in agreement with the predicted values because the adjusted determination coefficient (R (Adj)²) was 0.9708 and the level of significance was P pressure of 654 Mpa, temperature of 74 °C, pressure-holding time of 13.6 min, and nisin concentration of 328 IU/mL. The validation of the model equation for predicting the optimum response values was verified effectively by ten test points that were not used in the establishment of the model. Compared with conventional HPP techniques, the main process advantages of HPP-nisin combination sterilization in the UHT milk are, lower pressure, temperature, natural preservative (nisin), and in a shorter treatment time. The synergistic inactivation of bacteria by HPP-nisin combination is a promising and natural method to increase the efficiency and safety of high-pressure pasteurization.

  12. Clostridium Perfringens Epsilon Toxin Binds to Membrane Lipids and Its Cytotoxic Action Depends on Sulfatide.

    Directory of Open Access Journals (Sweden)

    Carles Gil

    Full Text Available Epsilon toxin (Etx is one of the major lethal toxins produced by Clostridium perfringens types B and D, being the causal agent of fatal enterotoxemia in animals, mainly sheep and goats. Etx is synthesized as a non-active prototoxin form (proEtx that becomes active upon proteolytic activation. Etx exhibits a cytotoxic effect through the formation of a pore in the plasma membrane of selected cell targets where Etx specifically binds due to the presence of specific receptors. However, the identity and nature of host receptors of Etx remain a matter of controversy. In the present study, the interactions between Etx and membrane lipids from the synaptosome-enriched fraction from rat brain (P2 fraction and MDCK cell plasma membrane preparations were analyzed. Our findings show that both Etx and proEtx bind to lipids extracted from lipid rafts from the two different models as assessed by protein-lipid overlay assay. Lipid rafts are membrane microdomains enriched in cholesterol and sphingolipids. Binding of proEtx to sulfatide, phosphatidylserine, phosphatidylinositol (3-phosphate and phosphatidylinositol (5-phosphate was detected. Removal of the sulphate groups via sulfatase treatment led to a dramatic decrease in Etx-induced cytotoxicity, but not in proEtx-GFP binding to MDCK cells or a significant shift in oligomer formation, pointing to a role of sulfatide in pore formation in rafts but not in toxin binding to the target cell membrane. These results show for the first time the interaction between Etx and membrane lipids from host tissue and point to a major role for sulfatides in C. perfringens epsilon toxin pathophysiology.

  13. Organization of the cpe locus in CPE-positive clostridium perfringens type C and D isolates.

    Directory of Open Access Journals (Sweden)

    Jihong Li

    2010-06-01

    Full Text Available Clostridium perfringens enterotoxin (encoded by the cpe gene contributes to several important human, and possibly veterinary, enteric diseases. The current study investigated whether cpe locus organization in type C or D isolates resembles one of the three (one chromosomal and two plasmid-borne cpe loci commonly found amongst type A isolates. Multiplex PCR assays capable of detecting sequences in those type A cpe loci failed to amplify products from cpe-positive type C and D isolates, indicating these isolates possess different cpe locus arrangements. Therefore, restriction fragments containing the cpe gene were cloned and sequenced from two type C isolates and one type D isolate. The obtained cpe locus sequences were then used to construct an overlapping PCR assay to assess cpe locus diversity amongst other cpe-positive type C and D isolates. All seven surveyed cpe-positive type C isolates had a plasmid-borne cpe locus partially resembling the cpe locus of type A isolates carrying a chromosomal cpe gene. In contrast, all eight type D isolates shared the same plasmid-borne cpe locus, which differed substantially from the cpe locus present in other C. perfringens by containing two copies of an ORF with 67% identity to a transposase gene (COG4644 found in Tn1546, but not previously associated with the cpe gene. These results identify greater diversity amongst cpe locus organization than previously appreciated, providing new insights into cpe locus evolution. Finally, evidence for cpe gene mobilization was found for both type C and D isolates, which could explain their cpe plasmid diversity.

  14. A Thermophilic Phage Endolysin Fusion to a Clostridium perfringens-Specific Cell Wall Binding Domain Creates an Anti-Clostridium Antimicrobial with Improved Thermostability

    Directory of Open Access Journals (Sweden)

    Steven M. Swift

    2015-06-01

    Full Text Available Clostridium perfringens is the third leading cause of human foodborne bacterial disease and is the presumptive etiologic agent of necrotic enteritis among chickens. Treatment of poultry with antibiotics is becoming less acceptable. Endolysin enzymes are potential replacements for antibiotics. Many enzymes are added to animal feed during production and are subjected to high-heat stress during feed processing. To produce a thermostabile endolysin for treating poultry, an E. coli codon-optimized gene was synthesized that fused the N-acetylmuramoyl-L-alanine amidase domain from the endolysin of the thermophilic bacteriophage ɸGVE2 to the cell-wall binding domain (CWB from the endolysin of the C. perfringens-specific bacteriophage ɸCP26F. The resulting protein, PlyGVE2CpCWB, lysed C. perfringens in liquid and solid cultures. PlyGVE2CpCWB was most active at pH 8, had peak activity at 10 mM NaCl, 40% activity at 150 mM NaCl and was still 16% active at 600 mM NaCl. The protein was able to withstand temperatures up to 50° C and still lyse C. perfringens. Herein, we report the construction and characterization of a thermostable chimeric endolysin that could potentially be utilized as a feed additive to control the bacterium during poultry production.

  15. Molecular typing of Clostridium perfringens isolated from swine in slaughterhouses from São Paulo State, Brazil Tipagem molecular de Clostridium perfringens isolados de suínos em abatedouros do estado de São Paulo, Brasil

    Directory of Open Access Journals (Sweden)

    Thais Sebastiana Porfida Ferreira

    2012-08-01

    Full Text Available Clostridium perfringens is an anaerobic Gram-positive bacterium known as common pathogen for humans, for domestic and wildlife animals. Although infections caused by C. perfringens type C and A in swine are well studied, just a few reports describe the genetic relationship among strains in the epidemiological chain of swine clostridioses, as well as the presence of the microorganism in the slaughterhouses. The aim of the present study was to isolate C. perfringens from feces and carcasses from swine slaughterhouses, characterize the strains in relation to the presence of enterotoxin, alpha, beta, epsilon, iota and beta-2 toxins genes, using polymerase chain reaction (PCR and comparing strains by means of Pulsed field gel electrophoresis (PFGE. Clostridium perfringens isolation frequencies in carcasses and finishing pig intestines were of 58.8% in both types of samples. According to the polymerase chain reaction assay, only alfa toxin was detected, being all isolates also negative to enterotoxin and beta2 toxin. Through PFGE technique, the strains were characterized in 35 pulsotypes. In only one pulsotype, the isolate from carcass sample was grouped with fecal isolate of the same animal, suggesting that the risk of cross-contamination was low. Despite the high prevalence of C. perfringens in swine carcasses from the slaughterhouses assessed, the risk of food poisoning to Brazilian pork consumers is low, since all strains were negative to cpe-gene, codifying enterotoxin.Clostridium perfringens é uma bactéria Gram positiva anaeróbica, conhecida por infectar os seres humanos, animais domésticos e de vida selvagem. Apesar de as infecções causadas por C. perfringens tipo C e A em suínos serem bastante estudadas, poucos relatos descrevem a relação genética entre as linhagens envolvidas na cadeia epidemiológica da clostridiose suína, bem como a presença do microorganismo em abatedouros. O objetivo do presente estudo foi isolar C

  16. Acid Sphingomyelinase Promotes Cellular Internalization of Clostridium perfringens Iota-Toxin.

    Science.gov (United States)

    Nagahama, Masahiro; Takehara, Masaya; Miyamoto, Kazuaki; Ishidoh, Kazumi; Kobayashi, Keiko

    2018-05-20

    Clostridium perfringens iota-toxin is a binary actin-ADP-ribosylating toxin composed of the enzymatic component Ia and receptor binding component Ib. Ib binds to a cell surface receptor, forms Ib oligomer in lipid rafts, and associates with Ia. The Ia-Ib complex then internalizes by endocytosis. Here, we showed that acid sphingomyelinase (ASMase) facilitates the cellular uptake of iota-toxin. Inhibitions of ASMase and lysosomal exocytosis by respective blockers depressed cell rounding induced by iota-toxin. The cytotoxicity of the toxin increased in the presence of Ca 2+ in extracellular fluids. Ib entered target cells in the presence but not the absence of Ca 2+ . Ib induced the extracellular release of ASMase in the presence of Ca 2+ . ASMase siRNA prevented the cell rounding induced by iota-toxin. Furthermore, treatment of the cells with Ib resulted in the production of ceramide in cytoplasmic vesicles. These observations showed that ASMase promotes the internalization of iota-toxin into target cells.

  17. Molecular typing and antimicrobial susceptibility of Clostridium perfringens from broiler chickens.

    Science.gov (United States)

    Gharaibeh, Saad; Al Rifai, Rami; Al-Majali, Ahmad

    2010-12-01

    Clostridium perfringens (Cp) causes necrotic enteritis disease in commercial poultry. Antimicrobials are used to control and treat this disease and sometimes clinical outbreaks do not respond well to certain treatments. This study was designed to isolate Cp from clinical cases, type these isolates by multiplex PCR, and determine their antimicrobial susceptibility by micro-dilution method. A total of 67 Cp isolates were obtained from 155 broiler chicken flocks. All isolates were classified as type A and non-enterotoxin producers. Lincomycin, erythromycins, and tilmicosin showed very high minimal inhibitory concentration (MIC) 50 of ≥256 μg/ml. However, tylosin, amoxicillin, ampicillin, penicillin, florfenicol, danofloxacin, enrofloxacin, chlortetracycline, doxycycline, and oxytetracycline had variable MIC₅₀ of 64, 0.5, 1, 1, 8, 4, 8, 4, 8, 0.5 μg/ml, respectively. It is recommended that Cp infections in Jordan be treated with either penicillins or tetracyclines especially amoxicillin and oxytetracycline. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Susceptibility of Clostridium perfringens strains from broiler chickens to antibiotics and anticoccidials.

    Science.gov (United States)

    Martel, A; Devriese, L A; Cauwerts, K; De Gussem, K; Decostere, A; Haesebrouck, F

    2004-02-01

    Clostridium perfringens strains isolated in 2002 from the intestines of broiler chickens from 31 different farms located in Belgium were tested for susceptibility to 12 antibiotics used for therapy, growth promotion or prevention of coccidiosis. All strains were uniformly sensitive to the ionophore antibiotics monensin, lasalocid, salinomycin, maduramycin and narasin. All were sensitive to avilamycin, tylosin and amoxicillin, while flavomycin (bambermycin) showed low or no activity. Chlortetracycline and oxytetracycline were active at very low concentrations, but low-level acquired resistance was detected in 66% of the strains investigated. Fifty percent of these strains carried the tetP(B) resistance gene, while the tet(Q) gene was detected in only one strain. One strain with high-level resistance against tetracyclines carried the tet(M) gene. Sixty-three percent of the strains showed low-level resistance to lincomycin. The lnu(A) and lnu(B) genes were each only found in one strain. Compared with a similar investigation carried out in 1980, an increase was seen in resistance percentages with lincomycin (63% against 49%) and a slight decrease with tetracycline (66% against 74%).

  19. Spore membrane(s) as the site of damage within heated Clostridium perfringens spores.

    Science.gov (United States)

    Flowers, R S; Adams, D M

    1976-02-01

    Clostridium perfringens spores were injured by ultrahigh-temperature treatment at 105 C for 5 min. Injury was manifested as an increased sensitivity to polymyxin and neomycin. Since many of the survivors could not germinate normally the ultrahigh-temperature-treated spores were sensitized to and germinated by lysozyme. Polymyxin reportedly acts upon the cell membrane. Neomycin may inhibit protein synthesis and has surface-active properties. Injured spores were increasingly sensitive to known surface-active agents, sodium lauryl sulfate, sodium deoxycholate, and Roccal, a quaternary ammonium compound. Injured spores sensitive to polymyxin and neomycin also were osmotically fragile and died during outgrowth in a liquid medium unless the medium was supplemented with 20% sucrose, 10% dextran, or 10% polyvinylpyrrolidone. The results suggested that a spore structure destined to become cell membrane or cell wall was the site of injury. Repair of injury during outgrowth in the presence of protein, deoxyribonucleic acid, ribonucleic acid and cell wall synthesis inhibitors was consistent with this hypothesis.

  20. Embryonated chicken eggs as an alternative model for mixed Clostridium perfringens and Eimeria tenella infection in chickens.

    Science.gov (United States)

    Alnassan, Alaa Aldin; Shehata, Awad Ali; Kotsch, Marianne; Lendner, Matthias; Daugschies, Arwid; Bangoura, Berit

    2013-06-01

    The chorioallantoic membrane (CAM) of chicken embryo eggs is a suitable model for viral and bacterial infections. In the present study, a new approach for testing the pathogenesis and virulence of Clostridium perfringens and Eimeria tenella dual infections as a model using the CAM of embryonated chicken eggs was developed. For this purpose, 24 specific pathogen-free (SPF) embryonated chicken eggs were divided into four groups (n = 6) and designated group E, group CP, group CPE, and NC. Sporozoites of E. tenella (20,000 sporozoites) were inoculated into 10-day-old embryonated SPF chicken eggs (groups E and CPE) via allantoic sac route. At 15-day-old, eggs of groups CP and CPE were infected with 10 (4)  cfu C. perfringens via the same route. Assessment of pathogenicity was assessed using gross and histopathological lesions. Embryo mortality reached 17 % after mono-infection with C. perfringens and/or E. tenella and 50 % in the mixed-infected group. Lesions in the CAMs were most numerous and most severe in co-infected eggs (group CPE), reaching the maximum score of 3 in 50 % of the inoculated eggs (P < 0.01). In Eimeria spp.-infected eggs (group E), lesions of score were between 1 and 2. Mono-infection with C. perfringens did not lead to a significant occurrence of lesions. Histopathological investigations of the CAM revealed clusters of Gram-positive bacteria, infiltration with leukocytes, lymphocytes, and developmental stages of E. tenella in the co-infected group. These data suggest that embryonated eggs could be an in ovo model for studying the pathogenesis of mixed infection with Eimeria and C. perfringens.

  1. Use of natural ingredients to control growth of Clostridium perfringens in naturally cured frankfurters and hams.

    Science.gov (United States)

    Jackson, Armitra L; Kulchaiyawat, Charlwit; Sullivan, Gary A; Sebranek, Joseph G; Dickson, James S

    2011-03-01

    A major concern for processed meats marketed as natural/organic is that they do not contain nitrite in concentrations known to be most effective for inhibiting foodborne pathogens. Supplemental treatments to increase the level and consistency of antimicrobial protection in these products may be important to provide consumers with the degree of safety that they have come to expect from conventionally cured meats. Therefore, the objective of this study was to identify and test ingredients that might improve processed meat product safety without altering their natural/organic status. Eight treatments of hams and frankfurters were prepared: (A) uncured control (typical ingredients except nitrite and nitrate); (B) conventionally cured control (erythorbate, nitrite, and a lactate-diacetate blend); (C) natural nitrate cure (including starter culture containing Staphylococcus carnosus); (D) natural nitrate cure (culture and natural antimicrobial A containing a vinegar, lemon, and cherry powder blend); (E) natural nitrate cure (culture and antimicrobial B containing a cultured sugar and vinegar blend); (F) natural nitrite cure without additional antimicrobials; (G) natural nitrite cure with natural antimicrobial A; and (H) natural nitrite cure with antimicrobial B. For the hams, treatments C, D, E, and H impacted growth of Clostridium perfringens to the same extent (P cured control (approximately 2 log less growth over time than uncured control). For frankfurters, treatments D, G, and H had an effect (approximately 1 log) on growth equivalent to that of the conventionally cured control (P cured meats have more potential for pathogen growth than conventionally cured products, but supplemental natural ingredients offer safety improvement.

  2. Decontamination of Clostridium perfringens and Salmonella spp. in Thai Fermented Fish (Pla-ra) by Gamma Radiation

    International Nuclear Information System (INIS)

    Prakhongsil, P.; Phianphak, W.; Malakrong, A.; Komolamisra, C.

    2014-01-01

    Gamma radiation can be applied as a decontamination method to eliminate microorganisms in fermented food. In this study, samples of Thai fermented fish were evaluated for microbiological and hygienic qualities and then exposed to gamma irradiation. Prior to irradiation, Salmonella spp. and Clostridium perfringens were detected and the results were found contaminated in five samples from twenty-six of Thai fermented fish samples ; Nile tilapia fish (Oreochromisniloticus), bighead carp fish (Aristichthys nobilis) and common snakehead fish (Channa striata) using VIDAS Salmonella Easy SLM assay and standard conventional assay for C. perfringens. For detecting of living parasites helminths, fifteen samples were assayed for liver fluke (Opisthorchis viverrini) and Gnathostoma spinigerum, but neither was found. When exposed to gamma irradiation, results showed that the minimum dose of 2.70 kGy could sufficiently eliminate Salmonella spp. from fermented Nile tilapia fish (Oreochromis nioloticus), whereas a higher dose of 6.16 kGy was required to reduce C. perfringens from130 CFU/g and 10 CFU/g to less than 10 CFU/g in fermented Nile tilapia fish and common snakehead fish (Channa striata) fish.

  3. Cloning, recombinant production, crystallization and preliminary X-ray diffraction studies of a family 84 glycoside hydrolase from Clostridium perfringens

    International Nuclear Information System (INIS)

    Ficko-Blean, Elizabeth; Boraston, Alisdair B.

    2005-01-01

    Crystallization of a family 84 glycoside hydrolase, a putative virulence factor, secreted by C. perfringens is reported. Clostridium perfringens is a ubiquitous environmental organism that is capable of causing a variety of diseases in mammals, including gas gangrene and necrotic enteritis in humans. The activity of a secreted hyaluronidase, attributed to the NagH protein, contributes to the pathogenicity of this organism. The family 84 catalytic module of one of the three homologues of NagH found in C. perfringens (ATCC 13124) has been cloned. The 69 kDa catalytic module of NagJ, here called GH84C, was overproduced in Escherichia coli and purified by immobilized metal-affinity chromatography (IMAC). Crystals belonging to space group I222 or I2 1 2 1 2 1 with unit-cell parameters a = 130.39, b = 150.05, c = 155.43 Å were obtained that diffracted to 2.1 Å. Selenomethionyl crystals have also been produced, leading to the possibility of solving the phase problem by MAD using synchrotron radiation

  4. Distribution of sewage pollution around a maritime Antarctic research station indicated by faecal coliforms, Clostridium perfringens and faecal sterol markers

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Kevin A.; Thompson, Anu

    2004-02-01

    This study describes the distribution of sewage pollution markers (faecal coliforms, Clostridium perfringens and faecal sterols) in seawater and marine sediments around Rothera Research Station, Antarctic Peninsula. Untreated sewage waste has been released from this site since 1975, creating the potential for long-term contamination of the benthic environment. Faecal coliform concentrations in seawater reached background levels within 300 m of the outfall. In sediment cores, both C. perfringens and faecal coliform concentrations declined with distance from the outfall, though C. perfringens persisted at greater depths in the sediment. High concentrations of 5{beta}(H)-cholestan-3{beta}-ol (coprostanol) relative to the corresponding 5{alpha}-epimer (cholestanol), indicative of sewage pollution, were only found in sediments within 200 m of the sewage outfall. This study has shown that sewage contamination is limited to the immediate vicinity of the sewage outfall. Nevertheless, a sewage treatment plant was installed in February 2003 to reduce this contamination further. - Sewage contamination of seawater and marine sediments near Rothera Research Station (Antarctic Peninsula) was limited to the immediate vicinity of the outfall.

  5. Distribution of sewage pollution around a maritime Antarctic research station indicated by faecal coliforms, Clostridium perfringens and faecal sterol markers

    International Nuclear Information System (INIS)

    Hughes, Kevin A.; Thompson, Anu

    2004-01-01

    This study describes the distribution of sewage pollution markers (faecal coliforms, Clostridium perfringens and faecal sterols) in seawater and marine sediments around Rothera Research Station, Antarctic Peninsula. Untreated sewage waste has been released from this site since 1975, creating the potential for long-term contamination of the benthic environment. Faecal coliform concentrations in seawater reached background levels within 300 m of the outfall. In sediment cores, both C. perfringens and faecal coliform concentrations declined with distance from the outfall, though C. perfringens persisted at greater depths in the sediment. High concentrations of 5β(H)-cholestan-3β-ol (coprostanol) relative to the corresponding 5α-epimer (cholestanol), indicative of sewage pollution, were only found in sediments within 200 m of the sewage outfall. This study has shown that sewage contamination is limited to the immediate vicinity of the sewage outfall. Nevertheless, a sewage treatment plant was installed in February 2003 to reduce this contamination further. - Sewage contamination of seawater and marine sediments near Rothera Research Station (Antarctic Peninsula) was limited to the immediate vicinity of the outfall

  6. Riverbed sediments in the Apies River, South Africa: recommending the use of both Clostridium perfringens and Escherichia coli as indicators of faecal pollution

    CSIR Research Space (South Africa)

    Abia, ALK

    2015-12-01

    Full Text Available . Real-time polymerase chain reaction (RT-PCR) was used to confirm isolates. E. coli and C. perfringens were enumerated in sediment by firstly using the water displacement approach to dislodge organisms from sediment and then subsequently followed...

  7. Comparison of toxicity neutralization-, ELISA- and PCR tests for typing of Clostridium perfringens and detection of the enterotoxin gene by PCR

    DEFF Research Database (Denmark)

    Møller, Kristian; Ahrens, Peter

    1996-01-01

    A polymerase chain reaction (PCR) was developed for the specific amplification of a part of each of the five Clostridium perfringens toxin genes: alpha (alpha), beta (beta), epsilon (epsilon), iota (iota), and enterotoxin (CPE). While the toxicity neutralization test (TNT) only showed limited...

  8. Effects of Eimeria maxima and Clostridium perfringens infections on Cecal Microbiome in Broiler Chickens Analyzed by 16S rRNA Sequencing

    Science.gov (United States)

    Background: Necrotic enteritis (NE) and coccidiosis are considered two of the priority enteric diseases impacting poultry production in the U.S. and Europe, and are responsible for the annual economic loss of US $6 billion and $ 3 billion, respectively. NE is caused by Clostridium perfringens (CP), ...

  9. Vaccination with Clostridium perfringens recombinant proteins in combination with Montanide™ ISA 71 VG adjuvant increases protection against experimental necrotic enteritis in commercial broiler chickens

    Science.gov (United States)

    This study was performed to compare four Clostridium perfringens recombinant proteins as vaccine candidates using the Montanide™ ISA 71 VG adjuvant in an experimental model of necrotic enteritis. Broiler chickens were immunized with clostridial recombinant proteins with ISA 71 VG, and intestinal le...

  10. Draft genome sequences of clostridium perfringens strain LLY_N11, a pathogenic isolate of necrotic enteritis from a healthy chicken

    Science.gov (United States)

    Clostridium perfringens strain LLY_N11 is a commensal bacterial isolate from a healthy chicken that produced a necrotic enteritis in experimental studies. Here we present the assembly and annotation of its genome, which may provide further insights into improved understanding of the molecular mechan...

  11. The safe enterocin DD14 is a leaderless two-peptide bacteriocin with anti-Clostridium perfringens activity.

    Science.gov (United States)

    Caly, Delphine L; Chevalier, Mickaël; Flahaut, Christophe; Cudennec, Benoit; Al Atya, Ahmed Khassaf; Chataigné, Gabrielle; D'Inca, Romain; Auclair, Eric; Drider, Djamel

    2017-03-01

    Enterococcus faecalis 14, a strain previously isolated from meconium, displayed activity against four Clostridium perfringens isolates when co-cultured on agar plates. The anti-Clostridium activity was ascribed to the production of enterocin DD14, which was subsequently purified. The minimum inhibitory concentration (MIC) of enterocin DD14 against one collection strain and one clinical C. perfringens strain was determined at 50 µg/mL. Furthermore, using the intestinal epithelial cell line IPEC-1, it was shown that E. faecalis 14 was not cytotoxic after 24 h of contact, and no cytotoxicity was observed when IPEC-1 cells were incubated with pure enterocin DD14 for 4 h. Enterocin DD14 was characterised using mass spectrometry and was shown to consist of two small proteins of 5200.74 Da and 5206.41 Da, respectively. The two peptides (DD14A and DD14B) have highly similar amino acid sequences and no signal peptide, which classifies enterocin DD14 as a class IIb leaderless two-peptide bacteriocin. The genes encoding DD14A and DD14B were sequenced and were shown to be 100% identical to other previously described enterocins MR10A and MR10B, in contrast to the producing strains, which are different. Consequently, the present in vitro study supports the potential of this E. faecalis 14 strain and/or its purified enterocin DD14 as putative anti-C. perfringens compounds in chickens. Copyright © 2017. Published by Elsevier B.V.

  12. Clostridium perfringens challenge and dietary fat type affect broiler chicken performance and fermentation in the gastrointestinal tract.

    Science.gov (United States)

    Józefiak, D; Kierończyk, B; Rawski, M; Hejdysz, M; Rutkowski, A; Engberg, R M; Højberg, O

    2014-06-01

    The aim of the present work was to examine how different fats commonly used in the feed industry affect broiler performance, nutrient digestibility and microbial fermentation in the gastrointestinal tract of broiler chickens challenged with virulent Clostridium perfringens strains. Two experiments were carried out, each including 480-day-old male broilers (Ross 308), which were randomly distributed to eight experimental groups using six replicate pens per treatment and 10 birds per pen. In Experiment 1, birds were fed diets containing soybean oil, palm kernel fatty acid distillers, rendered pork fat and lard. In Experiment 2, birds were fed diets containing rapeseed oil, coconut oil, beef tallow and palm oil. In both experiments, the birds were either not challenged or challenged with a mixture of three C. perfringens type A strains. Irrespective of the fat type present in the diet, C. perfringens did not affect broiler chicken body weight gain (BWG) and mortality in either of the two experiments. The BWG was affected by dietary fat type in both experiments, indicating that the fatty acid composition of the fat source affects broiler growth performance. In particular, the inclusion of animal fats tended to improve final BW to a greater extent compared with the inclusion of unsaturated vegetable oils. In Experiment 2, irrespective of the dietary fat type present in the diet, C. perfringens challenge significantly impaired feed conversion ratio in the period from 14 to 28 days (1.63 v. 1.69) and at 42 days (1.65 v. 1.68). In both experiments apparent metabolizable energy values were affected by dietary fat type. Irrespective of the fat type present in the diet, C. perfringens challenge decreased the digesta pH in the crop and ileum, but had no effect in cecal contents. Moreover, in Experiment 1, total organic acid concentration in the ileum was two to three times lower on soybean oil diets as compared with other treatments, indicating that C. perfringens as well as

  13. The CpAL quorum sensing system regulates production of hemolysins CPA and PFO to build Clostridium perfringens biofilms.

    Science.gov (United States)

    Vidal, Jorge E; Shak, Joshua R; Canizalez-Roman, Adrian

    2015-06-01

    Clostridium perfringens strains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by the C. perfringens Agr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. Although C. perfringens strains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrB mutant strains were not able to produce biofilms, a ΔluxS mutant produced wild-type levels. The transcript levels of CpAL-regulated cpa and pfoA genes, but not cpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpa and ΔpfoA mutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpb made wild-type levels. Biofilm formation was restored in complemented Δcpa/cpa and ΔpfoA/pfoA strains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation in C. perfringens by increasing levels of certain toxins required to build biofilms. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  14. The CpAL Quorum Sensing System Regulates Production of Hemolysins CPA and PFO To Build Clostridium perfringens Biofilms

    Science.gov (United States)

    Shak, Joshua R.; Canizalez-Roman, Adrian

    2015-01-01

    Clostridium perfringens strains produce severe diseases, including myonecrosis and enteritis necroticans, in humans and animals. Diseases are mediated by the production of potent toxins that often damage the site of infection, e.g., skin epithelium during myonecrosis. In planktonic cultures, the regulation of important toxins, such as CPA, CPB, and PFO, is controlled by the C. perfringens Agr-like (CpAL) quorum sensing (QS) system. Strains also encode a functional LuxS/AI-2 system. Although C. perfringens strains form biofilm-like structures, the regulation of biofilm formation is poorly understood. Therefore, our studies investigated the role of CpAL and LuxS/AI-2 QS systems and of QS-regulated factors in controlling the formation of biofilms. We first demonstrate that biofilm production by reference strains differs depending on the culture medium. Increased biomass correlated with the presence of extracellular DNA in the supernatant, which was released by lysis of a fraction of the biofilm population and planktonic cells. Whereas ΔagrB mutant strains were not able to produce biofilms, a ΔluxS mutant produced wild-type levels. The transcript levels of CpAL-regulated cpa and pfoA genes, but not cpb, were upregulated in biofilms compared to planktonic cultures. Accordingly, Δcpa and ΔpfoA mutants, in type A (S13) or type C (CN3685) backgrounds, were unable to produce biofilms, whereas CN3685Δcpb made wild-type levels. Biofilm formation was restored in complemented Δcpa/cpa and ΔpfoA/pfoA strains. Confocal microscopy studies further detected CPA partially colocalizing with eDNA on the biofilm structure. Thus, CpAL regulates biofilm formation in C. perfringens by increasing levels of certain toxins required to build biofilms. PMID:25824838

  15. Mechanisms of antibacterial action of Quinoxaline 1,4-di-N-oxides against Clostridium perfringens and Brachyspira hyodysenteriae

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    Fanfan Xu

    2016-12-01

    Full Text Available Quinoxaline 1,4-di-N-oxides (QdNOs are a class of bioreductive compounds, however their antibacterial mechanisms are still unclarified. The aim of this study was to assess the ability of two representative QdNO drugs, cyadox (CYA and olaquindox (OLA, to produce reactive oxide species (ROS in Gram-positive anaerobe Clostridium perfringens CVCC1125 and Gram-negative anaerobe Brachyspira hyodysenteriae B204. In addition, the effects of QdNOs on the integrity of bacterial cell walls and membranes as well as the morphological alterations and DNA oxidative damage in C. perfringens and B. hyodysenteriae were analyzed. It was demonstrated that under anaerobic conditions, QdNOs were metabolized into the reduced products which did not show any antibacterial activity. A significant dose-related increase of intracellular ROS level and intracellular hydroxyl radicals were evident in bacteria exposed to QdNOs. The result of biochemical assay showed that the cell walls and membranes of the bacteria treated with QdNOs were damaged. After exposure to 1/2MIC to 4MIC of CYA and OLA, C. perfringens and B. hyodysenteriae became elongated and filamentous. Morphological observation with scanning and transmission electron microscopes revealed rupture, loss of cytoplasmic material and cell lysis in QdNO-treated bacteria, indicating serious damage of cells. There was an increase of 8-OHdG in the two strains treated by QdNOs, but it was lower in Gram-positive than in Gram-negative bacteria. Agarose gel electrophoresis showed the degradation of chromosomal DNA in both of the two anaerobes treated by QdNOs. The results suggest that QdNOs may kill C. perfringens and B. hyodysenteriae via the generation of ROS and hydroxyl radicals from the bacterial metabolism of QdNOs, which cause oxidative damage in bacteria under anaerobic conditions.

  16. Prevalence and characteristics of Clostridium perfringens and Clostridium difficile in dogs and cats attended in diverse veterinary clinics from the Madrid region.

    Science.gov (United States)

    Álvarez-Pérez, Sergio; Blanco, José L; Harmanus, Celine; Kuijper, Ed J; García, Marta E

    2017-12-01

    Despite extensive research on the epidemiology of pathogenic clostridia in dogs and cats, most published studies focus on a selected animal population and/or a single veterinary medical centre. We assessed the burden of Clostridium perfringens and C. difficile shedding by small animals in 17 veterinary clinics located within the Madrid region (Spain) and differing in size, number and features of animals attended and other relevant characteristics. In addition, we studied the genetic diversity and antibiotic susceptibility of recovered isolates. Selective culture of all fecal specimens collected during a single week from dogs (n = 105) and cats (n = 37) attended in participating clinics yielded C. perfringens/C. difficile from 31%, 4.8% of the dogs, and 20%, 0% of the cats analyzed, respectively, and three dogs yielded both species. Furthermore, 17 animals (15 dogs and two cats) that yielded a positive culture for either species were recruited for a follow-up survey and C. perfringens was again obtained from nine dogs. Considerable differences in prevalence were observed among participating clinics for both clostridial species. C. perfringens isolates (n = 109) belonged to toxinotypes A (97.2%) and E (three isolates from one dog), whereas C. difficile isolates (n = 18) belonged to the toxigenic ribotypes 106 (33.3%) and 154 (16.7%), a 009-like ribotype (33.3%) and an unknown non-toxigenic ribotype (16.7%). Amplified fragment length polymorphism-based fingerprinting classified C. perfringens and C. difficile isolates into 105 and 15 genotypes, respectively, and tested isolates displayed in vitro resistance to benzylpenicillin (2.8%, 88.8%), clindamycin (0%, 16.7%), erythromycin (0.9%, 16.7%), imipenem (1.8%, 100%), levofloxacin (0.9%, 100%), linezolid (5.5%, 0%), metronidazole (4.6%, 0%) and/or tetracycline (7.3%, 0%). All animals from which multiple isolates were retrieved yielded ≥2 different genotypes and/or antimicrobial susceptibility profiles

  17. Recombinant Lactobacillus casei expressing Clostridium perfringens toxoids α, β2, ε and β1 gives protection against Clostridium perfringens in rabbits.

    Science.gov (United States)

    Zhao, Li; Guo, Zhihou; Liu, Jiali; Wang, Zi; Wang, Ruichong; Li, Yijing; Wang, Li; Xu, Yigang; Tang, Lijie; Qiao, Xinyuan

    2017-07-13

    The present study used Lactobacillus casei ATCC 393 as antigen delivery system to express C. perfringens toxoids α-β2-ε-β1 to construct the recombination Lactobacillus casei pPG-2-α-β2-ε-β1/L. casei 393. After being induced by 1% xylose, the specificity and integrity of recombinant strain were determined by Western-blotting. Rabbits as native animal model were immunized orally with pPG-2-α-β2-ε-β1/L. casei 393 and the titers of specific IgG and sIgA were determined by ELISA. The result showed that oral administration with the recombinants could elicit both local mucosal and systemic immune responses. The proliferation of spleen lymphocytes in rabbits immunized with pPG-2-α-β2-ε-β1/L. casei 393 was observed. Levels of IL-4 and IFN-γ produced were significantly higher in lymphocytes isolated from the vaccine group than those from the control groups. Flow cytometry assay showed that both the percentages of CD4+T cells and CD8+T cells from the vaccine group were significantly increased than the control groups. All these results showed that immunizing with recombinants can elicit both humoral immunity and cellular immunity. Besides, in order to determine the effectiveness of oral immunization with pPG-2-α-β2-ε-β1/L. casei 393, rabbits of vaccine group and control groups were challenged with 1×LD 100 unit of culture filtrate of C. perfringens type C and type D toxins respectively. After challenge, 100% of the immunized rabbits survived, while the rabbits of the control group were killed within 48h. Observation on histopathology showed that histopathological changes were obviously found in heart, liver, spleen, lung, kidney, intestine and brain of rabbits from the control groups, while no apparent histopathological change was observed in the vaccine group. All the results show that pPG-2-α-β2-ε-β1/L. casei 393 can eliciteffective immunoprotection against C. perfringens. All of these suggest that the use of pPG-2-α-β2-ε-β1/L. casei 393 can be

  18. Exposure to β-lactams results in the alteration of penicillin-binding proteins in Clostridium perfringens.

    Science.gov (United States)

    Park, Miseon; Rafii, Fatemeh

    2017-06-01

    Clostridium perfringens causes a variety of mild to severe infections in humans and other animals. A decrease in the affinity of penicillin-binding protein (PBP) transpeptidases for β-lactams is considered one of the mechanisms of β-lactam resistance in bacteria. Two strains of C. perfringens isolated from bovines and one isolated from a chicken, which had decreased susceptibility to β-lactams, had variations in the amino acid sequences of the central penicillin-binding regions of the PBPs. β-Lactam-resistant mutants of another C. perfringens strain, ATCC 13124, were selected in vitro to determine the effects of exposure to β-lactams on the PBP genes. Cultures of the wild type rapidly developed resistance to penicillin G, cephalothin and ceftriaxone. The susceptibilities of all of the selected mutants to some other β-lactams also decreased. The largest PBP found in C. perfringens, CPF_2395, appeared to be the primary target of all three drugs. Strain resistant to penicillin G had mutation resulting in the substitution of one amino acid within the central penicillin-binding/transpeptidase domain, but the ceftrioxane and cephalothin-resistant strains had mutations resulting in the substitution of two amino acids in this region. The cephalothin-resistant mutant also had additional mutations in the CPF_0340 and CPF_2218 genes in this critical region. No other mutations were observed in the three other PBPs of the in vitro resistant mutants. Resistance development also altered the growth rate and cell morphology of the mutants, so in addition to the PBPs, some other genes, including regulatory genes, may have been affected during the interaction with β-lactam antibiotics. This is the first study showing the effects of β-lactam drugs on the substitution of amino acids in PBPs of C. perfringens and points to the need for studies to detect other unknown alterations affecting the physiology of resistant strains. Published by Elsevier Ltd.

  19. Identification of novel Clostridium perfringens type E strains that carry an iota toxin plasmid with a functional enterotoxin gene.

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    Kazuaki Miyamoto

    Full Text Available Clostridium perfringens enterotoxin (CPE is a major virulence factor for human gastrointestinal diseases, such as food poisoning and antibiotic associated diarrhea. The CPE-encoding gene (cpe can be chromosomal or plasmid-borne. Recent development of conventional PCR cpe-genotyping assays makes it possible to identify cpe location (chromosomal or plasmid in type A isolates. Initial studies for developing cpe genotyping assays indicated that all cpe-positive strains isolated from sickened patients were typable by cpe-genotypes, but surveys of C. perfringens environmental strains or strains from feces of healthy people suggested that this assay might not be useful for some cpe-carrying type A isolates. In the current study, a pulsed-field gel electrophoresis Southern blot assay showed that four cpe-genotype untypable isolates carried their cpe gene on a plasmid of ∼65 kb. Complete sequence analysis of the ∼65 kb variant cpe-carrying plasmid revealed no intact IS elements and a disrupted cytosine methyltransferase (dcm gene. More importantly, this plasmid contains a conjugative transfer region, a variant cpe gene and variant iota toxin genes. The toxin genes encoded by this plasmid are expressed based upon the results of RT-PCR assays. The ∼65 kb plasmid is closely related to the pCPF4969 cpe plasmid of type A isolates. MLST analyses indicated these isolates belong to a unique cluster of C. perfringens. Overall, these isolates carrying a variant functional cpe gene and iota toxin genes represent unique type E strains.

  20. Metabolic dependent and independent pH-drop shuts down VirSR quorum sensing in Clostridium perfringens.

    Science.gov (United States)

    Adachi, Keika; Ohtani, Kaori; Kawano, Michio; Singh, Ravindra Pal; Yousuf, Basit; Sonomoto, Kenji; Shimizu, Tohru; Nakayama, Jiro

    2018-05-01

    Clostridium perfringens produces various exotoxins and enzymes that cause food poisoning and gas gangrene. The genes involved in virulence are regulated by the agr-like quorum sensing (QS) system, which consists of a QS signal synthesis system and a VirSR two-component regulatory system (VirSR TCS) which is a global regulatory system composed of signal sensor kinase (VirS) and response regulator (VirR). We found that the perfringolysin O gene (pfoA) was transiently expressed during mid-log phase of bacterial growth; its expression was rapidly shut down thereafter, suggesting the existence of a self-quorum quenching (sQQ) system. The sQQ system was induced by the addition of stationary phase culture supernatant (SPCS). Activity of the sQQ system was heat stable, and was present following filtration through the ultrafiltration membrane, suggesting that small molecules acted as sQQ agents. In addition, sQQ was also induced by pure acetic and butyric acids at concentrations equivalent to those in the stationary phase culture, suggesting that organic acids produced by C. perfringens were involved in sQQ. In pH-controlled batch culture, sQQ was greatly diminished; expression level of pfoA extended to late-log growth phase, and was eventually increased by one order of magnitude. Furthermore, hydrochloric acid induced sQQ at the same pH as was used in organic acids. SPCS also suppressed the expression of genes regulated by VirSR TCS. Overall, the expression of virulence factors of C. perfringens was downregulated by the sQQ system, which was mediated by primary acidic metabolites and acidic environments. This suggested the possibility of pH-controlled anti-virulence strategies. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  1. Molecular characterization of podoviral bacteriophages virulent for Clostridium perfringens and their comparison with members of the Picovirinae.

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    Nikolay V Volozhantsev

    Full Text Available Clostridium perfringens is a Gram-positive, spore-forming anaerobic bacterium responsible for human food-borne disease as well as non-food-borne human, animal and poultry diseases. Because bacteriophages or their gene products could be applied to control bacterial diseases in a species-specific manner, they are potential important alternatives to antibiotics. Consequently, poultry intestinal material, soil, sewage and poultry processing drainage water were screened for virulent bacteriophages that lysed C. perfringens. Two bacteriophages, designated ΦCPV4 and ΦZP2, were isolated in the Moscow Region of the Russian Federation while another closely related virus, named ΦCP7R, was isolated in the southeastern USA. The viruses were identified as members of the order Caudovirales in the family Podoviridae with short, non-contractile tails of the C1 morphotype. The genomes of the three bacteriophages were 17.972, 18.078 and 18.397 kbp respectively; encoding twenty-six to twenty-eight ORF's with inverted terminal repeats and an average GC content of 34.6%. Structural proteins identified by mass spectrometry in the purified ΦCP7R virion included a pre-neck/appendage with putative lyase activity, major head, tail, connector/upper collar, lower collar and a structural protein with putative lysozyme-peptidase activity. All three podoviral bacteriophage genomes encoded a predicted N-acetylmuramoyl-L-alanine amidase and a putative stage V sporulation protein. Each putative amidase contained a predicted bacterial SH3 domain at the C-terminal end of the protein, presumably involved with binding the C. perfringens cell wall. The predicted DNA polymerase type B protein sequences were closely related to other members of the Podoviridae including Bacillus phage Φ29. Whole-genome comparisons supported this relationship, but also indicated that the Russian and USA viruses may be unique members of the sub-family Picovirinae.

  2. Sialidases affect the host cell adherence and epsilon toxin-induced cytotoxicity of Clostridium perfringens type D strain CN3718.

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    Jihong Li

    2011-12-01

    Full Text Available Clostridium perfringens type B or D isolates, which cause enterotoxemias or enteritis in livestock, produce epsilon toxin (ETX. ETX is exceptionally potent, earning it a listing as a CDC class B select toxin. Most C. perfringens strains also express up to three different sialidases, although the possible contributions of those enzymes to type B or D pathogenesis remain unclear. Type D isolate CN3718 was found to carry two genes (nanI and nanJ encoding secreted sialidases and one gene (nanH encoding a cytoplasmic sialidase. Construction in CN3718 of single nanI, nanJ and nanH null mutants, as well as a nanI/nanJ double null mutant and a triple sialidase null mutant, identified NanI as the major secreted sialidase of this strain. Pretreating MDCK cells with NanI sialidase, or with culture supernatants of BMC206 (an isogenic CN3718 etx null mutant that still produces sialidases enhanced the subsequent binding and cytotoxic effects of purified ETX. Complementation of BMC207 (an etx/nanH/nanI/nanJ null mutant showed this effect is mainly attributable to NanI production. Contact between BMC206 and certain mammalian cells (e.g., enterocyte-like Caco-2 cells resulted in more rapid sialidase production and this effect involved increased transcription of BMC206 nanI gene. BMC206 was shown to adhere to some (e.g. Caco-2 cells, but not all mammalian cells, and this effect was dependent upon sialidase, particularly NanI, expression. Finally, the sialidase activity of NanI (but not NanJ or NanH could be enhanced by trypsin. Collectively these in vitro findings suggest that, during type D disease originating in the intestines, trypsin may activate NanI, which (in turn could contribute to intestinal colonization by C. perfringens type D isolates and also increase ETX action.

  3. A novel Hsp70 inhibitor prevents cell intoxication with the actin ADP-ribosylating Clostridium perfringens iota toxin

    Science.gov (United States)

    Ernst, Katharina; Liebscher, Markus; Mathea, Sebastian; Granzhan, Anton; Schmid, Johannes; Popoff, Michel R.; Ihmels, Heiko; Barth, Holger; Schiene-Fischer, Cordelia

    2016-01-01

    Hsp70 family proteins are folding helper proteins involved in a wide variety of cellular pathways. Members of this family interact with key factors in signal transduction, transcription, cell-cycle control, and stress response. Here, we developed the first Hsp70 low molecular weight inhibitor specifically targeting the peptide binding site of human Hsp70. After demonstrating that the inhibitor modulates the Hsp70 function in the cell, we used the inhibitor to show for the first time that the stress-inducible chaperone Hsp70 functions as molecular component for entry of a bacterial protein toxin into mammalian cells. Pharmacological inhibition of Hsp70 protected cells from intoxication with the binary actin ADP-ribosylating iota toxin from Clostridium perfringens, the prototype of a family of enterotoxins from pathogenic Clostridia and inhibited translocation of its enzyme component across cell membranes into the cytosol. This finding offers a starting point for novel therapeutic strategies against certain bacterial toxins. PMID:26839186

  4. The majority of atypical cpb2 genes in Clostridium perfringens isolates of different domestic animal origin are expressed.

    Science.gov (United States)

    Kircanski, Jasmina; Parreira, Valeria R; Whiteside, Samantha; Pei, Yanlong; Prescott, John F

    2012-10-12

    This study examined the prevalence and expression of the "consensus" and the "atypical"cpb2 genes in Clostridium perfringens isolates from cattle, chickens, dogs, goats, horses, pigs and sheep using polymerase chain reaction (PCR), sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by Western blotting. Almost all porcine isolates (12/14) carried and expressed the consensus form of cpb2 but, when present in 108 non-porcine isolates, the gene was usually the atypical form (40 atypical versus 9 consensus). Western blotting showed expression in 30 of 40 (75%) atypical cpb2-positive isolates, considerably more frequently than reported previously. CPB2 was expressed by almost all (20/21) the consensus cpb2-positive isolates, regardless of source. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. A complex array of Hpr consensus DNA recognition sequences proximal to the enterotoxin gene in Clostridium perfringens type A.

    Science.gov (United States)

    Brynestad, S; Iwanejko, L A; Stewart, G S; Granum, P E

    1994-01-01

    Enterotoxin production in Clostridium perfringens is both strain dependent and sporulation associated. Underlying these phenotypic observations must lie a genetic and molecular explanation and the principal keys will be held within the DNA sequence both upstream and downstream of the structural gene cpe. In accordance with the above we have sequenced 4.1 kbp of DNA upstream of cpe in the type strain NCTC 8239. A region of DNA extending up to 1.5 kb 5' to cpe is conserved in all enterotoxin-positive strains. This region contains a putative ORF with substantial homology to an ORF in the Salmonella typhimurium IS200 insertion element and, in addition, contains multiple perfect consensus DNA-binding sequences for the Bacillus subtilis transition state regulator Hpr. The detailed structural elements revealed by the sequence analysis are presented and used to develop a new perspective on the molecular basis of enterotoxin production in this important food-poisoning bacterium.

  6. Effect of low-dose gamma irradiation on enterotoxin-positive strains of Clostridium perfringens Type A

    International Nuclear Information System (INIS)

    Barnhart, H.M. Jr.

    1976-01-01

    The effect of low-dose gamma irradiation on selected enterotoxin producing strains of Clostridium perfringens Type A was studied. The radioresistance of three strains NCTC-8239, NCTC-10239 and NCTC-8798 in 0.1 percent peptone water, beef gravy and ground beef was determined for both vegetative cells and spores. D 10 values were approximately 30 Krad in 0.1 percent peptone water and 175 Krad in beef menstruums. D 10 values for spores were approximately 250 Krad in 0.1 percent peptone water and 335 Krad in beef. Low-level irradiation induced a 2 hr lag for cell recovery at 37 0 C following irradiation though this was strain dependent. Heat resistance of vegetative cells decreased following irradiation, although one strain was stimulated in growth response and unaltered in its heat resistance. Spore activation and germination were not affected by low-level irradiation. Spores were not significantly inactivated at this level. Irradiation had no effect on subsequent survival of vegetative cells stored at cold temperatures. Enterotoxin production by irradiated cultures was not affected by the irradiation treatment. A method for quantitating C. perfringens enterotoxin using crossed-immunoelectrophoresis was developed. It was found that this technique could detect at least .05 g of enterotoxin, could utilize crude enterotoxin preparations and was more sensitive than other methods based on biological activity

  7. Global Phenotypic Characterization of Effects of Fluoroquinolone Resistance Selection on the Metabolic Activities and Drug Susceptibilities of Clostridium perfringens Strains

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    Miseon Park

    2014-01-01

    Full Text Available Fluoroquinolone resistance affects toxin production of Clostridium perfringens strains differently. To investigate the effect of fluoroquinolone resistance selection on global changes in metabolic activities and drug susceptibilities, four C. perfringens strains and their norfloxacin-, ciprofloxacin-, and gatifloxacin-resistant mutants were compared in nearly 2000 assays, using phenotype microarray plates. Variations among mutant strains resulting from resistance selection were observed in all aspects of metabolism. Carbon utilization, pH range, osmotic tolerance, and chemical sensitivity of resistant strains were affected differently in the resistant mutants depending on both the bacterial genotype and the fluoroquinolone to which the bacterium was resistant. The susceptibilities to gentamicin and erythromycin of all resistant mutants except one increased, but some resistant strains were less susceptible to amoxicillin, cefoxitin, ceftriaxone, chloramphenicol, and metronidazole than their wild types. Sensitivity to ethidium bromide decreased in some resistant mutants and increased in others. Microarray analysis of two gatifloxacin-resistant mutants showed changes in metabolic activities that were correlated with altered expression of various genes. Both the chemical structures of fluoroquinolones and the genomic makeup of the wild types influenced the changes found in resistant mutants, which may explain some inconsistent reports of the effects of therapeutic use of fluoroquinolones on clinical isolates of bacteria.

  8. Detection of Different Genotypes of Clostridium perfringens in Feces of Healthy Dairy Cattle from China using Real-Time Duplex PCR Assay

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    Guanghua Wang, Jizhang Zhou, Fuying Zheng, Guozhen Lin, Xiaoan Cao, Xiaowei Gong and Changqing Qiu*

    2011-04-01

    Full Text Available Dual-labeled fluorescence hybridization probe-based multiplex quantitative real-time polymerase chain reaction (qPCR assay was used for the detection of Clostridium perfringens toxin genes alpha (cpa, beta (cpb, iota (ia, epsilon (etx, beta2 (cpb2 and enterotoxin (cpe directly from the feces of cattle. Fecal samples from 261 lactating cattle, belonging to three dairy herds in Ningxia (China, were examined using the developed assays. The duplex qPCR assay revealed that cpa, etx, cpb2 and cpe toxin genes were detected in 176 (100%, 15 (8.5%, 142 (80.7% and 4 (2.3% of 176 PCR positive samples, respectively. The findings of this study revealed that C. perfringens beta2-toxin-producing strains were widely prevalent in lactating cows in Ningxia, possibly playing an important role in C. perfringens-associated diarrheal disease.

  9. Phospholipase C produced by Clostridium botulinum types C and D: comparison of gene, enzymatic, and biological activities with those of Clostridium perfringens alpha-toxin.

    Science.gov (United States)

    Fatmawati, Ni Nengah Dwi; Sakaguchi, Yoshihiko; Suzuki, Tomonori; Oda, Masataka; Shimizu, Kenta; Yamamoto, Yumiko; Sakurai, Jun; Matsushita, Osamu; Oguma, Keiji

    2013-01-01

    Clostridium botulinum type C and D strains recently have been found to produce PLC on egg yolk agar plates. To characterize the gene, enzymatic and biological activities of C. botulinum PLCs (Cb-PLCs), the cb-plc genes from 8 strains were sequenced, and 1 representative gene was cloned and expressed as a recombinant protein. The enzymatic and hemolytic activities of the recombinant Cb-PLC were measured and compared with those of the Clostridium perfringens alpha-toxin. Each of the eight cb-plc genes encoded a 399 amino acid residue protein preceded by a 27 residue signal peptide. The protein consists of 2 domains, the N- and C-domains, and the overall amino acid sequence identity between Cb-PLC and alpha-toxin was greater than 50%, suggesting that Cb-PLC is homologous to the alpha-toxin. The key residues in the N-domain were conserved, whereas those in the C-domain which are important in membrane interaction were different than in the alpha-toxin. As expected, Cb-PLC could hydrolyze egg yolk phospholipid, p-nitrophenylphosphorylcholine, and sphingomyelin, and also exhibited hemolytic activity;however, its activities were about 4- to over 200-fold lower than those of alpha-toxin. Although Cb-PLC showed weak enzymatic and biological activities, it is speculated that Cb-PLC might play a role in the pathogenicity of botulism or for bacterial survival.

  10. Probing Genomic Aspects of the Multi-Host Pathogen Clostridium perfringens Reveals Significant Pangenome Diversity, and a Diverse Array of Virulence Factors

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    Raymond Kiu

    2017-12-01

    Full Text Available Clostridium perfringens is an important cause of animal and human infections, however information about the genetic makeup of this pathogenic bacterium is currently limited. In this study, we sought to understand and characterise the genomic variation, pangenomic diversity, and key virulence traits of 56 C. perfringens strains which included 51 public, and 5 newly sequenced and annotated genomes using Whole Genome Sequencing. Our investigation revealed that C. perfringens has an “open” pangenome comprising 11667 genes and 12.6% of core genes, identified as the most divergent single-species Gram-positive bacterial pangenome currently reported. Our computational analyses also defined C. perfringens phylogeny (16S rRNA gene in relation to some 25 Clostridium species, with C. baratii and C. sardiniense determined to be the closest relatives. Profiling virulence-associated factors confirmed presence of well-characterised C. perfringens-associated exotoxins genes including α-toxin (plc, enterotoxin (cpe, and Perfringolysin O (pfo or pfoA, although interestingly there did not appear to be a close correlation with encoded toxin type and disease phenotype. Furthermore, genomic analysis indicated significant horizontal gene transfer events as defined by presence of prophage genomes, and notably absence of CRISPR defence systems in >70% (40/56 of the strains. In relation to antimicrobial resistance mechanisms, tetracycline resistance genes (tet and anti-defensins genes (mprF were consistently detected in silico (tet: 75%; mprF: 100%. However, pre-antibiotic era strain genomes did not encode for tet, thus implying antimicrobial selective pressures in C. perfringens evolutionary history over the past 80 years. This study provides new genomic understanding of this genetically divergent multi-host bacterium, and further expands our knowledge on this medically and veterinary important pathogen.

  11. Probing Genomic Aspects of the Multi-Host Pathogen Clostridium perfringens Reveals Significant Pangenome Diversity, and a Diverse Array of Virulence Factors.

    Science.gov (United States)

    Kiu, Raymond; Caim, Shabhonam; Alexander, Sarah; Pachori, Purnima; Hall, Lindsay J

    2017-01-01

    Clostridium perfringens is an important cause of animal and human infections, however information about the genetic makeup of this pathogenic bacterium is currently limited. In this study, we sought to understand and characterise the genomic variation, pangenomic diversity, and key virulence traits of 56 C. perfringens strains which included 51 public, and 5 newly sequenced and annotated genomes using Whole Genome Sequencing. Our investigation revealed that C. perfringens has an "open" pangenome comprising 11667 genes and 12.6% of core genes, identified as the most divergent single-species Gram-positive bacterial pangenome currently reported. Our computational analyses also defined C. perfringens phylogeny (16S rRNA gene) in relation to some 25 Clostridium species, with C. baratii and C. sardiniense determined to be the closest relatives. Profiling virulence-associated factors confirmed presence of well-characterised C. perfringens -associated exotoxins genes including α-toxin ( plc ), enterotoxin ( cpe ), and Perfringolysin O ( pfo or pfoA ), although interestingly there did not appear to be a close correlation with encoded toxin type and disease phenotype. Furthermore, genomic analysis indicated significant horizontal gene transfer events as defined by presence of prophage genomes, and notably absence of CRISPR defence systems in >70% (40/56) of the strains. In relation to antimicrobial resistance mechanisms, tetracycline resistance genes ( tet ) and anti-defensins genes ( mprF ) were consistently detected in silico ( tet : 75%; mprF : 100%). However, pre-antibiotic era strain genomes did not encode for tet , thus implying antimicrobial selective pressures in C. perfringens evolutionary history over the past 80 years. This study provides new genomic understanding of this genetically divergent multi-host bacterium, and further expands our knowledge on this medically and veterinary important pathogen.

  12. Genome-wide transcriptional profiling of Clostridium perfringens SM101 during sporulation

    NARCIS (Netherlands)

    Xiao, Yinghua; Hijum, van Sacha A.; Abee, Tjakko; Wells-Bennik, Marjon H.

    2014-01-01

    In this study we focus on the identification of new genes tentatively involved in sporulation and those that influence properties of spores and their ability to germinate. To this end, the sporulation stages of C. perfringens enterotoxic strain SM101 were characterized based on morphological

  13. Ultrasensitive Electrochemical Detection of Clostridium perfringens DNA Based Morphology-Dependent DNA Adsorption Properties of CeO2 Nanorods in Dairy Products

    Directory of Open Access Journals (Sweden)

    Xingcan Qian

    2018-06-01

    Full Text Available Foodborne pathogens such as Clostridium perfringens can cause diverse illnesses and seriously threaten to human health, yet far less attention has been given to detecting these pathogenic bacteria. Herein, two morphologies of nanoceria were synthesized via adjusting the concentration of NaOH, and CeO2 nanorod has been utilized as sensing material to achieve sensitive and selective detection of C. perfringens DNA sequence due to its strong adsorption ability towards DNA compared to nanoparticle. The DNA probe was tightly immobilized on CeO2/chitosan modified electrode surface via metal coordination, and the DNA surface density was 2.51 × 10−10 mol/cm2. Under optimal experimental conditions, the electrochemical impedance biosensor displays favorable selectivity toward target DNA in comparison with base-mismatched and non-complementary DNA. The dynamic linear range of the proposed biosensor for detecting oligonucleotide sequence of Clostridium perfringens was from 1.0 × 10−14 to 1.0 × 10−7 mol/L. The detection limit was 7.06 × 10−15 mol/L. In comparison, differential pulse voltammetry (DPV method quantified the target DNA with a detection limit of 1.95 × 10−15 mol/L. Moreover, the DNA biosensor could detect C. perfringens extracted DNA in dairy products and provided a potential application in food quality control.

  14. ENSAYO PRELIMINAR DE LA ACTIVIDAD ANTIBACTERIANA DE EXTRACTOS DE ALLIUM SATIVUM, CORIANDRUM SATIVUM, EUGENIA CARYOPHYLLATA, ORIGANUM VULGARE, ROSMARINUS OFFICINALIS Y THYMUS VULGARIS FRENTE A CLOSTRIDIUM PERFRINGENS

    OpenAIRE

    Ardila Q., Martha I; Vargas A., Andrés F; Pérez C., Jorge E; Mejía G., Luis F

    2009-01-01

    Se evaluó la actividad antibacteriana frente a Clostridium perfringens (cepa ATCC: 13124) por el método de Kirby Bauer en agar SPS de los aceites esenciales o extractos vegetales obtenidos con solventes orgánicos de diferente polaridad a partir de Allium sativum (ajo), Coriandrum sativum (cilantro), Eugenia Caryophyllata (clavo de olor), Origanum vulgare (orégano), Rosmarinus officinalis (romero) y Thymus vulgaris (tomillo), utilizando la vancomicina como control. Los extractos obtenidos por ...

  15. Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population

    OpenAIRE

    Marie-Lou Gaucher; Marie-Lou Gaucher; Marie-Lou Gaucher; Gabriel G. Perron; Julie Arsenault; Ann Letellier; Martine Boulianne; Sylvain Quessy

    2017-01-01

    Extensive use of antibiotic growth promoters (AGPs) in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is k...

  16. Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population

    Science.gov (United States)

    Gaucher, Marie-Lou; Perron, Gabriel G.; Arsenault, Julie; Letellier, Ann; Boulianne, Martine; Quessy, Sylvain

    2017-01-01

    Extensive use of antibiotic growth promoters (AGPs) in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is key to a sustainable and cost-effective production in the absence of AGPs. Using polymerase chain reaction and pulsed-field gel electrophoresis, we evaluated how the C. perfringens population evolved in drug-free commercial broiler chicken farms, either healthy or affected with recurring clinical necrotic enteritis outbreaks, over a 14-month period. We show that a high genotypic richness was associated with an increased risk of clinical necrotic enteritis. Also, necrotic enteritis-affected farms had a significant reduction of C. perfringens genotypic richness over time, an increase in the proportion of C. perfringens strains harboring the cpb2 gene, the netB gene, or both. Thus, necrotic enteritis occurrence is correlated with the presence of an initial highly diverse C. perfringens population, increasing the opportunity for the selective sweep of particularly virulent genotypes. Disease outbreaks also appear to largely influence the evolution of this bacterial species in poultry farms over time. PMID:28567032

  17. Determination of enterotoxigenic Clostridium perfringens by detecting of the cpa and cpe genes in stool samples of human origin, associated to gastrointestinal disease

    International Nuclear Information System (INIS)

    Oropeza Barrios, Gletty

    2014-01-01

    A molecular methodology is provided to the Centro Nacional de Referencia de Bacteriologia (CNRB) of the Instituto Costarricense de Investigacion y Ensenanza en Nutricion y Salud. An opportune diagnosis is realized of enterotoxigenic Clostridium perfringens in stool samples of sporadic cases and cases associated to foodborne disease outbreaks. DNA extraction of the white microorganism was performed through the methodology implemented in the CNRB. The technique of polymerase chain reaction (PCR) were adapted and standardized to establish the identification of C. perfringens to species level and detection of cpe gene coding for enterotoxin. The sensitivity of the method was determined in a selective culture medium for C. perfringens (Tryptose sulfite cycloserine Agar). A detection limit of about 2,3 x 10 4 CFU/ml was reached for the cpe gene and at least 2,8 x 10 2 CFU/ml for the cpa gene. Retrospective analysis of 61 samples of diarrheal stool suspicious by C. perfringens is performed to evaluate the efficacy of the technique. Three outbreaks caused by C. perfringens were identified and a 10% of positivity in the samples were obtained analyzed during the period between July 2012-March 2014 [es

  18. Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population

    Directory of Open Access Journals (Sweden)

    Marie-Lou Gaucher

    2017-05-01

    Full Text Available Extensive use of antibiotic growth promoters (AGPs in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is key to a sustainable and cost-effective production in the absence of AGPs. Using polymerase chain reaction and pulsed-field gel electrophoresis, we evaluated how the C. perfringens population evolved in drug-free commercial broiler chicken farms, either healthy or affected with recurring clinical necrotic enteritis outbreaks, over a 14-month period. We show that a high genotypic richness was associated with an increased risk of clinical necrotic enteritis. Also, necrotic enteritis-affected farms had a significant reduction of C. perfringens genotypic richness over time, an increase in the proportion of C. perfringens strains harboring the cpb2 gene, the netB gene, or both. Thus, necrotic enteritis occurrence is correlated with the presence of an initial highly diverse C. perfringens population, increasing the opportunity for the selective sweep of particularly virulent genotypes. Disease outbreaks also appear to largely influence the evolution of this bacterial species in poultry farms over time.

  19. Recurring Necrotic Enteritis Outbreaks in Commercial Broiler Chicken Flocks Strongly Influence Toxin Gene Carriage and Species Richness in the Resident Clostridium perfringens Population.

    Science.gov (United States)

    Gaucher, Marie-Lou; Perron, Gabriel G; Arsenault, Julie; Letellier, Ann; Boulianne, Martine; Quessy, Sylvain

    2017-01-01

    Extensive use of antibiotic growth promoters (AGPs) in food animals has been questioned due to the globally increasing problem of antibiotic resistance. For the poultry industry, digestive health management following AGP withdrawal in Europe has been a challenge, especially the control of necrotic enteritis. Much research work has focused on gut health in commercial broiler chicken husbandry. Understanding the behavior of Clostridium perfringens in its ecological niche, the poultry barn, is key to a sustainable and cost-effective production in the absence of AGPs. Using polymerase chain reaction and pulsed-field gel electrophoresis, we evaluated how the C. perfringens population evolved in drug-free commercial broiler chicken farms, either healthy or affected with recurring clinical necrotic enteritis outbreaks, over a 14-month period. We show that a high genotypic richness was associated with an increased risk of clinical necrotic enteritis. Also, necrotic enteritis-affected farms had a significant reduction of C. perfringens genotypic richness over time, an increase in the proportion of C. perfringens strains harboring the cpb2 gene, the netB gene, or both. Thus, necrotic enteritis occurrence is correlated with the presence of an initial highly diverse C. perfringens population, increasing the opportunity for the selective sweep of particularly virulent genotypes. Disease outbreaks also appear to largely influence the evolution of this bacterial species in poultry farms over time.

  20. Characterization of Clostridium perfringens isolates from healthy turkeys and from turkeys with necrotic enteritis

    DEFF Research Database (Denmark)

    Lyhs, Ulrike; Perko-Mäkelä, P.; Kallio, H.

    2013-01-01

    from 1998 to 2012. Furthermore, C. perfringens isolates from healthy and diseased turkeys were characterized and their genetic diversity was investigated using pulsed-field gel electrophoresis (PFGE). Isolates (n = 212) from birds with necrotic gut lesions and from healthy flocks of 30 commercial...... turkey farms were characterized for the presence of cpa, cpb, iA, etx, cpb2, and cpe and netB genes. A total of 93 C. perfringens isolates, including 55 from birds with necrotic gut lesions and 38 from healthy birds from 13 different farms, were analyzed with PFGE. All contract turkey farmers (n = 48......) of a turkey company that produces 99% of domestic turkey meat in Finland were interviewed about background information, management at the farm, and stress factors related to NE outbreaks. Pulsed-field gel electrophoresis analysis with SmaI restriction enzyme resulted in 30 PFGE patterns among the 92 C...

  1. Generation and characterization of recombinant bivalent fusion protein r-Cpib for immunotherapy against Clostridium perfringens beta and iota toxemia.

    Science.gov (United States)

    Das, Shreya; Majumder, Saugata; Kingston, Joseph J; Batra, Harsh V

    2016-02-01

    Clostridium perfringens beta (CPB) and iota (CPI) toxaemias result in some of the most lethal forms of haemorrhagic and necrotic enteritis and sudden death syndrome affecting especially neonates. While CPB enterotoxemia is one of the most common forms of clostridial enterotoxemia, CPI enterotoxemia though putatively considered to be rare is an emerging cause of concern. The similarities in clinical manifestation, gross and histopathology findings of both types of toxaemias coupled to the infrequency of CPI toxaemia might lead to symptomatic misidentification with Type C resulting in therapeutic failure due to habitual administration of CPB anti-toxin which is ineffective against CPI. Therefore in the present study, to generate a composite anti-toxin capable of neutralizing both toxaemias, a novel bivalent chimera r-Cpib was constructed by splicing the non-toxic C terminal binding regions of CPB and CPI, via a flexible glycine linker (G4S) by overlap-extension PCR. The fusion protein was characterized for its therapeutic abilities toward CPI and CPB toxin neutralizations. The r-Cpib was found to be non-toxic and could competitively inhibit binding of CPB to host cell receptors thereby reducing its cytotoxicity. Immunization of mice with r-Cpib generated specific antibodies capable of neutralizing the above toxaemias both in vitro and in vivo. Caco-2 cells exposed to a mixture of anti-r-Cpib sera and native CPI or CPB, displayed significantly superior protection against the respective toxins while passive challenge of mice with a similar mixture resulted in 83 and 91% protection against CPI and CPB respectively. Alternatively, mice exposed to a mixture of sham sera and native toxins died within 2-3 days. This work thus demonstrates r-Cpib as a novel bivalent fusion protein capable of efficient immunotherapy against C. perfringens CPI and CPB toxaemia. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Genotypic and phenotypic characterization of Clostridium perfringens isolates from Darmbrand cases in post-World War II Germany.

    Science.gov (United States)

    Ma, Menglin; Li, Jihong; McClane, Bruce A

    2012-12-01

    Clostridium perfringens type C strains are the only non-type-A isolates that cause human disease. They are responsible for enteritis necroticans, which was termed Darmbrand when occurring in post-World War II Germany. Darmbrand strains were initially classified as type F because of their exceptional heat resistance but later identified as type C strains. Since only limited information exists regarding Darmbrand strains, this study genetically and phenotypically characterized seven 1940s era Darmbrand-associated strains. Results obtained indicated the following. (i) Five of these Darmbrand isolates belong to type C, carry beta-toxin (cpb) and enterotoxin (cpe) genes on large plasmids, and express both beta-toxin and enterotoxin. The other two isolates are cpe-negative type A. (ii) All seven isolates produce highly heat-resistant spores with D(100) values (the time that a culture must be kept at 100°C to reduce its viability by 90%) of 7 to 40 min. (iii) All of the isolates surveyed produce the same variant small acid-soluble protein 4 (Ssp4) made by type A food poisoning isolates with a chromosomal cpe gene that also produce extremely heat-resistant spores. (iv) The Darmbrand isolates share a genetic background with type A chromosomal-cpe-bearing isolates. Finally, it was shown that both the cpe and cpb genes can be mobilized in Darmbrand isolates. These results suggest that C. perfringens type A and C strains that cause human food-borne illness share a spore heat resistance mechanism that likely favors their survival in temperature-abused food. They also suggest possible evolutionary relationships between Darmbrand strains and type A strains carrying a chromosomal cpe gene.

  3. Effects of Bacillus coagulans supplementation on the growth performance and gut health of broiler chickens with Clostridium perfringens-induced necrotic enteritis.

    Science.gov (United States)

    Wu, Yuanyuan; Shao, Yujing; Song, Bochen; Zhen, Wenrui; Wang, Zhong; Guo, Yuming; Shahid, Muhammad Suhaib; Nie, Wei

    2018-01-01

    The poultry industry is in need of effective antibiotic alternatives to control outbreaks of necrotic enteritis (NE) due to Clostridium perfringens . This study was conducted to investigate the effects of feeding Bacillus coagulans on the growth performance and gut health of broiler chickens with C. perfringens -induced NE. Two hundred and forty 1-day-old broiler chicks were randomly assigned to a 2 × 2 factorial arrangement with two dietary B. coagulans levels (0 or 4 × 10 9  CFU/kg of diet) and two disease challenge statuses (control or NE challenged). NE-induced reduction in body weight gain was relieved by the addition of B. coagulans into broiler diets compared with the NE-infected birds. NE infection damaged intestinal morphological structure, promoted intestinal C. perfringens growth and liver invasion, and enhanced anti- C. perfringens specific sIgA concentrations in the gut and specific IgG levels in serum compared with the uninfected birds. NE infection significantly ( P  coagulans showed a significant ( P  coagulans improved intestinal barrier structure, further increased specific sIgA levels and alkaline phosphatase (IAP) activity in the jejunum, enhanced the expression of jejunum lysozyme mRNA, and inhibited the growth, colonization, and invasion of C. perfringens ; in contrast, it reduced serum-specific IgG concentrations and jejunum IFN-γ mRNA levels. These results indicated that dietary B. coagulans supplementation appeared to be effective in preventing the occurrence and reducing the severity of C. perfringens -induced NE in broiler chickens.

  4. Adsorptive effects of di-tri-octahedral smectite on Clostridium perfringens alpha, beta, and beta-2 exotoxins and equine colostral antibodies.

    Science.gov (United States)

    Lawler, Jacquelin Boggs; Hassel, Diana M; Magnuson, Roberta J; Hill, Ashley E; McCue, Patrick M; Traub-Dargatz, Josie L

    2008-02-01

    To determine the adsorptive capability of di-tri-octahedral smectite (DTOS) on Clostridium perfringens alpha, beta, and beta-2 exotoxins and equine colostral antibodies. 3 C perfringens exotoxins and 9 colostral samples. Alpha, beta, and beta-2 exotoxins were individually co-incubated with serial dilutions of DTOS or bismuth subsalicylate, and the amount of toxin remaining after incubation was determined via toxin-specific ELISAs. Colostral samples from healthy mares were individually co-incubated with serial dilutions of DTOS, and colostral IgG concentrations were determined via single radial immunodiffusion assay. Di-tri-octahedral smectite decreased the amount of each C perfringens exotoxin in co-incubated samples in a dose-dependent manner and was more effective than bismuth subsalicylate at reducing exotoxins in vitro. Decreases in the concentration of IgG were detected in samples of colostrum that were combined with DTOS at 1:4 through 1:16 dilutions, whereas no significant decrease was evident with DTOS at the 1:32 dilution. Di-tri-octahedral smectite effectively adsorbed C perfringens exotoxins in vitro and had a dose-dependent effect on the availability of equine colostral antibodies. Results suggested that DTOS may be an appropriate adjunctive treatment in the management of neonatal clostridiosis in horses. In vivo studies are necessary to fully assess the clinical efficacy of DTOS treatment.

  5. Interaction of Clostridium perfringens epsilon-toxin with biological and model membranes: A putative protein receptor in cells.

    Science.gov (United States)

    Manni, Marco M; Sot, Jesús; Goñi, Félix M

    2015-03-01

    Epsilon-toxin (ETX) is a powerful toxin produced by some strains of Clostridium perfringens (classified as types B and D) that is responsible for enterotoxemia in animals. ETX forms pores through the plasma membrane of eukaryotic cells, consisting of a β-barrel of 14 amphipathic β-strands. ETX shows a high specificity for certain cell lines, of which Madin-Darby canine kidney (MDCK) is the first sensitive cell line identified and the most studied one. The aim of this study was to establish the role of lipids in the toxicity caused by ETX and the correlation of its activity in model and biological membranes. In MDCK cells, using cell counting and confocal microscopy, we have observed that the toxin causes cell death mediated by toxin binding to plasma membrane. Moreover, ETX binds and permeabilizes the membranes of giant plasma membrane vesicles (GPMV). However, little effect is observed on protein-free vesicles. The data suggest the essential role of a protein receptor for the toxin in cell membranes. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Use of Plant Extracts as an Effective Manner to Control Clostridium perfringens Induced Necrotic Enteritis in Poultry

    Science.gov (United States)

    Dominguez, J. E.; Chacana, A. P.

    2016-01-01

    Necrotic enteritis (NE) is an important concern in poultry industry since it causes economic losses, increased mortality, reduction of bird welfare, and contamination of chicken products for human consumption. For decades, the use of in-feed antimicrobial growth promoters (AGPs) has been the main strategy to control intestinal pathogens including Clostridium perfringens (CP), the causative agent of NE. However, the use of AGPs in animal diet has been linked to the emergence and transmission of antimicrobial resistance through food-borne microorganisms, which has led to the ban of AGPs in many countries. This scenario has challenged the poultry industry to search for safer alternative products in order to prevent NE. In this context, the utilization of natural plant extracts with antimicrobial properties appears as a promising and feasible tool to control NE in chicken. In this paper, we review the scientific studies analyzing the potential of plant extracts as alternative feed additives to reduce NE in poultry, with focus on two types of plant products that arise as promising candidates: tannins and essential oils. Some of these products showed antimicrobial activity against CP and coccidia in vitro and in vivo and are able to increase productive performance, emulating the bioactive properties of AGPs. PMID:27747227

  7. Roles of Asp179 and Glu270 in ADP-Ribosylation of Actin by Clostridium perfringens Iota Toxin.

    Directory of Open Access Journals (Sweden)

    Alexander Belyy

    Full Text Available Clostridium perfringens iota toxin is a binary toxin composed of the enzymatically active component Ia and receptor binding component Ib. Ia is an ADP-ribosyltransferase, which modifies Arg177 of actin. The previously determined crystal structure of the actin-Ia complex suggested involvement of Asp179 of actin in the ADP-ribosylation reaction. To gain more insights into the structural requirements of actin to serve as a substrate for toxin-catalyzed ADP-ribosylation, we engineered Saccharomyces cerevisiae strains, in which wild type actin was replaced by actin variants with substitutions in residues located on the Ia-actin interface. Expression of the actin mutant Arg177Lys resulted in complete resistance towards Ia. Actin mutation of Asp179 did not change Ia-induced ADP-ribosylation and growth inhibition of S. cerevisiae. By contrast, substitution of Glu270 of actin inhibited the toxic action of Ia and the ADP-ribosylation of actin. In vitro transcribed/translated human β-actin confirmed the crucial role of Glu270 in ADP-ribosylation of actin by Ia.

  8. Analysis of plasmid profiling as a method for rapid differentiation of food-associated Clostridium perfringens strains.

    Science.gov (United States)

    Jones, M K; Iwanejko, L A; Longden, M S

    1989-09-01

    Plasmid analysis of over 120 strains of Clostridium perfringens, isolated during food-poisoning incidents and from animal carcasses and food constituents with no association with food poisoning, showed the potential of plasmid profiling as a means of differentiating epidemiologically related strains. On average 65% of freshly isolated strains contained one or more plasmids which could be used in the analysis. Comparison of profiles of strains from unrelated sources or unrelated strains from the same source showed a particularly wide variety of plasmid profiles. Thus the possibility that epidemiologically-unrelated strains might possess similar profiles appears to be very low in this organism. Analysis of serologically-related strains from the same source revealed similar plasmid profiles in all the plasmid-bearing strains examined. A high proportion (71%) of fresh and well-characterized food-poisoning strains possessed plasmids of 6.2 kb in size (compared with 19% of non-food-poisoning strains). The possible role of these plasmids is discussed, since the structural gene encoding the enterotoxin type A was not present on any of the plasmids in the food-poisoning strains tested.

  9. Dynamics of plc gene transcription and α-toxin production during growth of Clostridium perfringens strains with contrasting α-toxin production

    DEFF Research Database (Denmark)

    Abildgaard, Lone; Schramm, Andreas; Rudi, Knut

    2009-01-01

    The aim of the present study was to investigate transcription dynamics of the α-toxin-encoding plc gene relative to two housekeeping genes (gyrA and rplL) in batch cultures of three Clostridium perfringens strains with low, intermediate, and high levels of α-toxin production, respectively. The plc...... transcript level was always low in the low α-toxin producing strain. For the two other strains, plc transcription showed an inducible pattern and reached a maximum level in the late exponential growth phase. The transcription levels were however inversely correlated to α-toxin production for the two strains....... We propose that this discrepancy is due to differences in plc translation rates between the strains and that strain-specific translational rates therefore must be determined before α-toxin production can be extrapolated from transcript levels in C. perfringens....

  10. Fatal Clostridium perfringens sepsis due to emphysematous gastritis and literature review.

    Science.gov (United States)

    Sarvari, Karoly Peter; Vasas, Bela; Kiss, Ildiko; Lazar, Andrea; Horvath, Istvan; Simon, Marianna; Peto, Zoltan; Urban, Edit

    2016-08-01

    A 76-year-old female patient was admitted to the Level I Emergency Department of University of Szeged with severe abdominal pain and vomiting. The clinical assessment with laboratory tests and radiological investigations confirmed severe sepsis associated with intravascular hemolysis and multiorgan failure and acute pancreatitis. On the abdominal CT, besides of other abnormalities, the presence of gas bubbles in the stomach, small intestines and liver were seen. The gastric alterations pointed to emphysematous gastritis. Despite of the medical treatment, the patient's condition quickly deteriorated and eight hours after admission the patient died. The autopsy evaluation revealed systemic infection of abdominal origin caused by gas-producing Gram-positive bacteria, and the post-mortem microbiological cultures confirmed the presence of Cloctridium perfringens in many abdominal organs. Emphysematous gastritis seemed to be the primary infectious focus. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Genome-Wide Transcriptional Profiling of Clostridium perfringens SM101 during Sporulation Extends the Core of Putative Sporulation Genes and Genes Determining Spore Properties and Germination Characteristics.

    Science.gov (United States)

    Xiao, Yinghua; van Hijum, Sacha A F T; Abee, Tjakko; Wells-Bennik, Marjon H J

    2015-01-01

    The formation of bacterial spores is a highly regulated process and the ultimate properties of the spores are determined during sporulation and subsequent maturation. A wide variety of genes that are expressed during sporulation determine spore properties such as resistance to heat and other adverse environmental conditions, dormancy and germination responses. In this study we characterized the sporulation phases of C. perfringens enterotoxic strain SM101 based on morphological characteristics, biomass accumulation (OD600), the total viable counts of cells plus spores, the viable count of heat resistant spores alone, the pH of the supernatant, enterotoxin production and dipicolinic acid accumulation. Subsequently, whole-genome expression profiling during key phases of the sporulation process was performed using DNA microarrays, and genes were clustered based on their time-course expression profiles during sporulation. The majority of previously characterized C. perfringens germination genes showed upregulated expression profiles in time during sporulation and belonged to two main clusters of genes. These clusters with up-regulated genes contained a large number of C. perfringens genes which are homologs of Bacillus genes with roles in sporulation and germination; this study therefore suggests that those homologs are functional in C. perfringens. A comprehensive homology search revealed that approximately half of the upregulated genes in the two clusters are conserved within a broad range of sporeforming Firmicutes. Another 30% of upregulated genes in the two clusters were found only in Clostridium species, while the remaining 20% appeared to be specific for C. perfringens. These newly identified genes may add to the repertoire of genes with roles in sporulation and determining spore properties including germination behavior. Their exact roles remain to be elucidated in future studies.

  12. Effect of meat ingredients (sodium nitrite and erythorbate) and processing (vacuum storage and packaging atmosphere) on germination and outgrowth of Clostridium perfringens spores in ham during abusive cooling.

    Science.gov (United States)

    Redondo-Solano, Mauricio; Valenzuela-Martinez, Carol; Cassada, David A; Snow, Daniel D; Juneja, Vijay K; Burson, Dennis E; Thippareddi, Harshavardhan

    2013-09-01

    The effect of nitrite and erythorbate on Clostridium perfringens spore germination and outgrowth in ham during abusive cooling (15 h) was evaluated. Ham was formulated with ground pork, NaNO2 (0, 50, 100, 150 or 200 ppm) and sodium erythorbate (0 or 547 ppm). Ten grams of meat (stored at 5 °C for 3 or 24 h after preparation) were transferred to a vacuum bag and inoculated with a three-strain C. perfringens spore cocktail to obtain an inoculum of ca. 2.5 log spores/g. The bags were vacuum-sealed, and the meat was heat treated (75 °C, 20 min) and cooled within 15 h from 54.4 to 7.2 °C. Residual nitrite was determined before and after heat treatment using ion chromatography with colorimetric detection. Cooling of ham (control) stored for 3 and 24 h, resulted in C. perfringens population increases of 1.46 and 4.20 log CFU/g, respectively. For samples that contained low NaNO2 concentrations and were stored for 3 h, C. perfringens populations of 5.22 and 2.83 log CFU/g were observed with or without sodium erythorbate, respectively. Residual nitrite was stable (p > 0.05) for both storage times. Meat processing ingredients (sodium nitrite and sodium erythorbate) and their concentrations, and storage time subsequent to preparation of meat (oxygen content) affect C. perfringens spore germination and outgrowth during abusive cooling of ham. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Adhesive properties of an outer structure of Clostridium perfringens type A isolated from piglets with with catarrhal enteritis Propriedades adesivas de uma estrutura externa de Clostridium perfringens tipo A isolada de leitões com enterite catarral

    Directory of Open Access Journals (Sweden)

    Elizabeth Pelosi Teixeira

    1999-07-01

    Full Text Available One strain (S32 of Clostridium perfringens type A was isolated from a case of catarrhal enteritis of piglets. This strain was able to adhere to HeLa cells showing an adherence index (AI of 25.15 ± 1.26 (mean ± 1 standard error of the mean. Treatment of the bacterial cells with trypsin (0.25mg/ml decreased in 70%-80% the AI and metaperiodate (10mg/ml abolished completely the adherence, suggesting that the structure responsible for this phenomenon was probably a glycoprotein. Heating of bacterial suspensions (100ºC/5 min before carrying out the adhesion test decreased the AI rendering it equal to the negative controls. Rabbit homologous S32 antiserum inhibited the adherence up to dilutions of 1: 640, at least. The piglet ileal loop assay, carried out with strains S32 and Jab-1 (negative control demonstrated that the strain S32 was able to adhere to the intestinal epithelial cells when examined after Gram staining. Transmission electron microcopy (TEM demonstrated that S32 strain displayed a loose fibrillar material not seen with Jab-1. Stabilization of the bacterial cells with homologous antiserum of strain S32, followed by staining with rhuteniun red, revealed loose long fibrillar material on the outer surface of the cells, that sometimes could be seen spreading out from the cells and linking bacterial cells. The question whether this structure might be an adhesin for this strain of Cl. perfringes type A, perhaps playing a role in the pathogenesis of the catarrhal enteritis of piglets, is dependent on further studies.Uma amostra (S32 de Clostridium perfringens tipo A foi isolada de um caso de enterite catarral em leitões. Esta amostra foi capaz de aderir a células HeLa mostrando um índice de adesão (AI de 25,15 ± 1,26 (media ± 1 erro padrão da media. Tratamento das células bacterianas com tripsina (0,25mg/ml diminuiu 70%-80% e metaperiodato (10mg/ml aboliu significantemente a adesão, sugerindo que a estrutura responsável por esta

  14. Caracterización molecular y resistencia antimicrobiana de aislamientos de Clostridium perfringens de diferentes orígenes en Costa Rica

    Directory of Open Access Journals (Sweden)

    María del Mar Gamboa-Coronado

    2011-12-01

    Full Text Available Clostridium perfringens es un bacilo Gram positivo, esporulado, anaerobio, ampliamente distribuido en la naturaleza, que produce cuatro toxinas principales α, β, ε y ι, las cuales permiten su clasificación en cinco toxinotipos (A-E. Algunas cepas producen una enterotoxina (CPE, codificada por el gen cpe, que causa diarrea en seres humanos y en algunos animales. La presencia de los genes de estas toxinas y la sensibilidad a los antibióticos se determinó en 81 cepas de C. perfringens previamente aisladas y que habían sido mantenidas a -80°C; 20 de suelos, 20 de origen animal, 20 de origen humano y 21 de alimentos cocidos no relacionados con brotes alimentarios. De acuerdo con los resultados de PCR, todas las cepas fueron clasificadas como C. perfringens tipo A, debido a que solo se les detectó el gen de la toxina α, mientras que el gen de la enterotoxina (cpe se detectó en dos cepas (2.5% aisladas de alimentos, tal como ha sido descrito en otras regiones del mundo. El 44% de las cepas fue resistente a algún antibiótico; clindamicina (41%, cloranfenicol (25%, penicilina (22% y metronidazol (20%. En general, las cepas provenientes de suelos presentaron los mayores porcentajes de resistencia a casi todos los antibióticos. El 40% de las cepas de suelo presentó multiresistencia (a tres o más grupos de antibióticos, el 30% de las de origen humano, el 14% de las de alimentos y el 5% de las de origen animal. Las altas tasas de resistencia encontradas podrían deberse al amplio uso de antibióticos como promotores de crecimiento de plantas y animales y esas cepas resistentes podrían actuar como reservorio de genes de resistencia que pueden transferirse entre bacterias de diversos ambientes.Molecular characterization and antimicrobial resistance of Clostridium perfringens isolates of different origins from Costa Rica. Clostridium perfringens, a Gram positive, spore-forming anaerobe, is widely distributed in nature. Based upon their

  15. Clostridium perfringens em rações e águas fornecidos a frangos de corte em granjas avícolas do interior paulista: Brasil Clostridium perfringens search in water and ration used in the raising of broiler in sheds of São Paulo State: Brazil

    Directory of Open Access Journals (Sweden)

    Rubén Pablo Schocken-Iturrino

    2010-02-01

    Full Text Available Através de métodos bacteriológicos convencionais, avaliou-se a contaminação por Clostridium perfringens na ração e água utilizadas na alimentação e dessedentação de frangos de corte em diferentes regiões avícolas do interior paulista. C. perfringens esteve presente em 42 e 30% das amostras de ração e águas analisadas, respectivamente. As médias das contagens foram 6,7 x 10-2UFC mL para as amostras de água e 3,69 x 10-2UFC g para as de rações. As altas freqüências e contagens de C. perfringens verificadas nas rações e nas águas podem estar associadas à falta de higiene geral na manipulação e armazenamento dos mesmos. Sugere-se o monitoramento periódico da presença de C. perfringens nestas fontes, com a finalidade de evitar tal patógeno, em vista que o mesmo pode causar um surto de enterite necrótica levando, assim a grandes prejuízos na produção avícola.Through conventional bacteriological methods, the contamination by Clostridium perfringens was evaluated in the ration and water used in the feeding of poultry chickens from different region of the interior from São Paulo. C. perfringens was present in 42 and 30% of the ration samples and waters analyzed respectively. The averages of the countings were 6.7 x 10-2CFU mL for the samples of water and 3.69 x 10-2CFU g for rations. The high frequencies and countings of C. perfringens verified in the rations and in the waters may be associated to the lack of general hygiene in the manipulation and storage of the same ones. These suggests a periodic monitoration of the presence of C. perfringens in these sources, with the purpose of avoiding such pathogen, in view that this organism can provoke an outbreak of necrotic enteritis, and cause great damages in the poultry production.

  16. Comparison of the Effect of Curing Ingredients Derived from Purified and Natural Sources on Inhibition of Clostridium perfringens Outgrowth during Cooling of Deli-Style Turkey Breast.

    Science.gov (United States)

    King, Amanda M; Glass, Kathleen A; Milkowski, Andrew L; Sindelar, Jeffrey J

    2015-08-01

    The antimicrobial impact of purified and natural sources of both nitrite and ascorbate were evaluated against Clostridium perfringens during the postthermal processing cooling period of deli-style turkey breast. The objective of phase I was to assess comparable concentrations of nitrite (0 or 100 ppm) and ascorbate (0 or 547 ppm) from both purified and natural sources. Phase II was conducted to investigate concentrations of nitrite (50, 75, or 100 ppm) from cultured celery juice powder and ascorbate (0, 250, or 500 ppm) from cherry powder to simulate alternative curing formulations. Ground turkey breast (75% moisture, 1.2% salt, pH 6.2) treatments were inoculated with C. perfringens spores (three-strain mixture) to yield 2.5 log CFU/g. Individual 50-g portions were vacuum packaged, cooked to 71.1°C, and chilled from 54.4 to 26.7°C in 5 h and from 26.7 to 7.2°C in 10 additional hours. Triplicate samples were assayed for growth of C. perfringens at predetermined intervals by plating on tryptose-sulfite-cycloserine agar; experiments were replicated three times. In phase I, uncured, purified nitrite, and natural nitrite treatments without ascorbate had 5.3-, 4.2-, and 4.4-log increases in C. perfringens, respectively, at 15 h, but nitrite and 547 ppm of ascorbate from either source. In phase II, 0, 50, 75, and 100 ppm of nitrite and 50 ppm of nitrite plus 250 ppm of ascorbate supported 4.5-, 3.9-, 3.5-, 2.2-, and 1.5-log increases in C. perfringens, respectively. In contrast, nitrite and 500 ppm of ascorbate or ≥75 ppm of nitrite and ≥250 ppm of ascorbate. These results confirm that equivalent concentrations of nitrite, regardless of the source, provide similar inhibition of C. perfringens during chilling and that ascorbate enhances the antimicrobial effect of nitrite on C. perfringens at concentrations commonly used in alternative cured meats.

  17. Combination treatment of clostridium perfringens spores to freezing and/or gamma irradiation

    International Nuclear Information System (INIS)

    El-Fouly, M.Z.; El-Zawahry, Y.A.; Aziz, N.H.

    1985-01-01

    Freezing process alone caused relatively low decrease in viable count of suspended spores in minced meat while it decreased the spore numbers suspended in saline solution by more than one log cycle especially in case of the Egyptian strain. An abrupt decrease in viable counts of clostridium spores was observed by application dose of 1KGY either before or after freezing followed by gradual decrease of viable counts up to 15 KGY. The synergestic effect of combined treatment was clearly obvious for spores suspended in minced meat, which usually contains protective agents which increase the resistance of microorganisms against the separate treatment of radiation of freezing especially with spores of NCTC 8798 strain. Freezing the saline suspending medium before or after irradiation after the sensitivity of clostridium spores by only small extent and gave negative synergestic effect in some treatment. The percentages of injured spores due to the combined treatment were ranged between 15-100% of the viable counts. The percentage of injured spores tended to increase as the radiation dose levels increased

  18. Bacterial spores as possible contaminants of biomedical materials and devices. [Bacillus anthracis, clostridium botulinum, C. perfringens, C. tetani

    Energy Technology Data Exchange (ETDEWEB)

    Grecz, N; Kang, T

    1973-01-01

    Destruction of spores on biomedical devices in drugs, and biologicals is essential for prevention of infection of patients with pathogenic sporeformers. Of particular concern are Clostridium tetani, C. perfringens, C. botulinum, Bacillus anthracis and other sporeforming pathogens. Spores are ubiquitous in nature and contamination of biomedical devices varies depending on manufacturing process, handling, raw materials and other variables. In the last 20 years the number of cases per year of specific notifiable diseases in the United States was as follows: tetanus, 120 to 500 cases, botulism, 7 to 47 cases, and anthrax, 2 to 10 cases. Gas gangrene is caused by a mixed flora consisting predominantly of sporeformers. C botulinum, which usually acts as saprophytic agent of food poisoning, may also initiate pathogenic processes; there are nine cases on record in the United States of botulism wound infections almost half of which ended in death. The spores of these organisms are distinguished by high radiation resistance and their erradication often requires severe radiation treatments. Representative bacterial spores in various suspending media show D/sub 10/ values (dose necessary to destroy 90 percent of a given population) ranging from approximately 0.1 to 0.4 Mrad. Some viruses show D/sub 10/ values up to greater than 1 Mrad. The D/sub 10/-values of spores vary depending on physical, chemical and biological factors. This variability is important in evaluation and selection of biological indicator organisms. Radiation sterilization of biomedical devices and biomedical materials must provide safety from infectious microorganisms including radiation resistant spores and viruses.

  19. Diverse modes of galacto-specific carbohydrate recognition by a family 31 glycoside hydrolase from Clostridium perfringens.

    Directory of Open Access Journals (Sweden)

    Julie M Grondin

    Full Text Available Clostridium perfringens is a commensal member of the human gut microbiome and an opportunistic pathogen whose genome encodes a suite of putative large, multi-modular carbohydrate-active enzymes that appears to play a role in the interaction of the bacterium with mucin-based carbohydrates. Among the most complex of these is an enzyme that contains a presumed catalytic module belonging to glycoside hydrolase family 31 (GH31. This large enzyme, which based on its possession of a GH31 module is a predicted α-glucosidase, contains a variety of non-catalytic ancillary modules, including three CBM32 modules that to date have not been characterized. NMR-based experiments demonstrated a preference of each module for galacto-configured sugars, including the ability of all three CBM32s to recognize the common mucin monosaccharide GalNAc. X-ray crystal structures of the CpGH31 CBM32s, both in apo form and bound to GalNAc, revealed the finely-tuned molecular strategies employed by these sequentially variable CBM32s in coordinating a common ligand. The data highlight that sequence similarities to previously characterized CBMs alone are insufficient for identifying the molecular mechanism of ligand binding by individual CBMs. Furthermore, the overlapping ligand binding profiles of the three CBMs provide a fail-safe mechanism for the recognition of GalNAc among the dense eukaryotic carbohydrate networks of the colonic mucosa. These findings expand our understanding of ligand targeting by large, multi-modular carbohydrate-active enzymes, and offer unique insights into of the expanding ligand-binding preferences and binding site topologies observed in CBM32s.

  20. Comparative genomics of four closely related Clostridium perfringens bacteriophages reveals variable evolution among core genes with therapeutic potential

    Directory of Open Access Journals (Sweden)

    Siragusa Gregory R

    2011-06-01

    Full Text Available Abstract Background Because biotechnological uses of bacteriophage gene products as alternatives to conventional antibiotics will require a thorough understanding of their genomic context, we sequenced and analyzed the genomes of four closely related phages isolated from Clostridium perfringens, an important agricultural and human pathogen. Results Phage whole-genome tetra-nucleotide signatures and proteomic tree topologies correlated closely with host phylogeny. Comparisons of our phage genomes to 26 others revealed three shared COGs; of particular interest within this core genome was an endolysin (PF01520, an N-acetylmuramoyl-L-alanine amidase and a holin (PF04531. Comparative analyses of the evolutionary history and genomic context of these common phage proteins revealed two important results: 1 strongly significant host-specific sequence variation within the endolysin, and 2 a protein domain architecture apparently unique to our phage genomes in which the endolysin is located upstream of its associated holin. Endolysin sequences from our phages were one of two very distinct genotypes distinguished by variability within the putative enzymatically-active domain. The shared or core genome was comprised of genes with multiple sequence types belonging to five pfam families, and genes belonging to 12 pfam families, including the holin genes, which were nearly identical. Conclusions Significant genomic diversity exists even among closely-related bacteriophages. Holins and endolysins represent conserved functions across divergent phage genomes and, as we demonstrate here, endolysins can have significant variability and host-specificity even among closely-related genomes. Endolysins in our phage genomes may be subject to different selective pressures than the rest of the genome. These findings may have important implications for potential biotechnological applications of phage gene products.

  1. Relative disease susceptibility and clostridial toxin antibody responses in three commercial broiler lines co-infected with Clostridium perfringens and Eimeria maxima using an experimental model of necrotic enteritis

    Science.gov (United States)

    Necrotic enteritis is an enteric disease of poultry resulting from infection by Clostridium perfringens with co-infection by Eimeria spp. constituting a major risk factor for disease pathogenesis. This study compared three commercial broiler chicken lines using an experimental model of necrotic ente...

  2. Development of an integrated model for heat transfer and dynamic growth of Clostridium perfringens during the cooling of cooked boneless ham.

    Science.gov (United States)

    Amézquita, A; Weller, C L; Wang, L; Thippareddi, H; Burson, D E

    2005-05-25

    Numerous small meat processors in the United States have difficulties complying with the stabilization performance standards for preventing growth of Clostridium perfringens by 1 log10 cycle during cooling of ready-to-eat (RTE) products. These standards were established by the Food Safety and Inspection Service (FSIS) of the US Department of Agriculture in 1999. In recent years, several attempts have been made to develop predictive models for growth of C. perfringens within the range of cooling temperatures included in the FSIS standards. Those studies mainly focused on microbiological aspects, using hypothesized cooling rates. Conversely, studies dealing with heat transfer models to predict cooling rates in meat products do not address microbial growth. Integration of heat transfer relationships with C. perfringens growth relationships during cooling of meat products has been very limited. Therefore, a computer simulation scheme was developed to analyze heat transfer phenomena and temperature-dependent C. perfringens growth during cooling of cooked boneless cured ham. The temperature history of ham was predicted using a finite element heat diffusion model. Validation of heat transfer predictions used experimental data collected in commercial meat-processing facilities. For C. perfringens growth, a dynamic model was developed using Baranyi's nonautonomous differential equation. The bacterium's growth model was integrated into the computer program using predicted temperature histories as input values. For cooling cooked hams from 66.6 degrees C to 4.4 degrees C using forced air, the maximum deviation between predicted and experimental core temperature data was 2.54 degrees C. Predicted C. perfringens growth curves obtained from dynamic modeling showed good agreement with validated results for three different cooling scenarios. Mean absolute values of relative errors were below 6%, and deviations between predicted and experimental cell counts were within 0.37 log10

  3. The application of rumen simulation technique (RUSITEC) for studying dynamics of the bacterial community and metabolome in rumen fluid and the effects of a challenge with Clostridium perfringens.

    Science.gov (United States)

    Wetzels, Stefanie U; Eger, Melanie; Burmester, Marion; Kreienbrock, Lothar; Abdulmawjood, Amir; Pinior, Beate; Wagner, Martin; Breves, Gerhard; Mann, Evelyne

    2018-01-01

    The rumen simulation technique (RUSITEC) is a well-established semicontinuous in vitro model for investigating ruminal fermentation; however, information on the stability of the ruminal bacterial microbiota and metabolome in the RUSITEC system is rarely available. The availability of high resolution methods, such as high-throughput sequencing and metabolomics improve our knowledge about the rumen microbial ecosystem and its fermentation processes. Thus, we used Illumina MiSeq 16S rRNA amplicon sequencing and a combination of direct injection mass spectrometry with a reverse-phase LC-MS/MS to evaluate the dynamics of the bacterial community and the concentration of several metabolites in a RUSITEC experiment as a function of time and in response to a challenge with a pathogenic Clostridium perfringens (C. perfringens) strain. After four days of equilibration, samples were collected on days 5, 6, 7, 10, 12 and 15 of the steady-state and experimental period. From a total of six fermenters, three non-infected fermenters were used for investigating time-dependent alterations; three fermenters were incubated with C. perfringens and compared with the non-infected vessels at days 10, 12 and 15. Along the time-line, there was no statistically significant change of the overall bacterial community, however, some phylotypes were enriched at certain time points. A decrease in Fibrobacter and Elusimicrobia over time was followed by an increase in Firmicutes and Actinobacteria. In contrast, classical fermentation measurements such as pH, redox potential, NH3-N, short chain fatty acids and the concentrations of metabolites determined by metabolomics (biogenic amines, hexoses and amino acids) remained stable throughout the experiment. In response to C. perfringens addition the concentrations of several amino acids increased. Although the overall bacterial community was not altered here either, some minor changes such as an enrichment of Synergistetes and Bacteroidetes were

  4. Experimental induction of abdominal tympany, abomasitis, and abomasal ulceration by intraruminal inoculation of Clostridium perfringens type A in neonatal calves.

    Science.gov (United States)

    Roeder, B L; Chengappa, M M; Nagaraja, T G; Avery, T B; Kennedy, G A

    1988-02-01

    The etiologic role of Clostridum perfringens type A in the acute abdominal syndrome characterized by abomasal and rumen tympany, abomasitis, and abomasal ulceration was investigated in neonatal calves. Eight calves, 4 to 12 days old, were inoculated intraruminally with toxigenic C perfringens type A. Before and after C perfringens inoculation, blood samples were collected from all calves for blood gas and serum biochemical analysis and for determination of serum copper concentration; ruminal fluid was obtained for isolation of C perfringens. Calves were monitored daily for clinical signs of the syndrome and, depending on the severity of clinical signs, they were either euthanatized or redosed within 4 to 7 days. After necropsy, specimens obtained from the abomasum and rumen for macroscopic and microscopic examination and for anaerobic bacteriologic culture were processed in routine manner. Intraruminal inoculation of C perfringens type A into healthy calves induced anorexia, depression, bloat, diarrhea, and in some calves, death. Serum copper concentration was within normal range. Necropsy revealed variable degrees of abomasitis, petechial and ecchymotic hemorrhages, and ulcers (ranging from pinpoint to nearly perforate) in the abomasum. Seven of those calves also had multiple trichobezoars in the rumen. These necropsy findings were not seen in calves (controls) given distilled H2O only. In affected calves, acute abdominal syndrome was unrelated to copper deficiency, and C perfringens type A given intraruminally was able to induce clinical signs similar to those of the naturally acquired disease.

  5. The effect of feeding a commercial essential oil product on Clostridium perfringens numbers in the intestine of broiler chickens measured by real-time PCR targeting the α-toxin-encoding gene (plc)

    DEFF Research Database (Denmark)

    Abildgaard, Lone; Højberg, Ole; Schramm, Andreas

    2010-01-01

    Proliferation of Clostridium perfringens type A in the broiler intestinal tract is related to poor growth and litter quality, and can under certain conditions lead to the development of necrotic enteritis (NE), a severe gastrointestinal disease in broilers. The aim of the present study was to inv...... quantification of C. perfringens type A in broilers, a real-time PCR assay, targeting the α-toxin-encoding plc gene, was developed for use in ileal and caecal samples and was shown to be a fast and reliable alternative to conventional plate counting....

  6. Caracterización molecular y resistencia antimicrobiana de aislamientos de Clostridium perfringens de diferentes orígenes en Costa Rica

    Directory of Open Access Journals (Sweden)

    María del Mar Gamboa-Coronado

    2011-12-01

    Full Text Available Clostridium perfringens es un bacilo Gram positivo, esporulado, anaerobio, ampliamente distribuido en la naturaleza, que produce cuatro toxinas principales α, β, ε y ι, las cuales permiten su clasificación en cinco toxinotipos (A-E. Algunas cepas producen una enterotoxina (CPE, codificada por el gen cpe, que causa diarrea en seres humanos y en algunos animales. La presencia de los genes de estas toxinas y la sensibilidad a los antibióticos se determinó en 81 cepas de C. perfringens previamente aisladas y que habían sido mantenidas a -80°C; 20 de suelos, 20 de origen animal, 20 de origen humano y 21 de alimentos cocidos no relacionados con brotes alimentarios. De acuerdo con los resultados de PCR, todas las cepas fueron clasificadas como C. perfringens tipo A, debido a que solo se les detectó el gen de la toxina α, mientras que el gen de la enterotoxina (cpe se detectó en dos cepas (2.5% aisladas de alimentos, tal como ha sido descrito en otras regiones del mundo. El 44% de las cepas fue resistente a algún antibiótico; clindamicina (41%, cloranfenicol (25%, penicilina (22% y metronidazol (20%. En general, las cepas provenientes de suelos presentaron los mayores porcentajes de resistencia a casi todos los antibióticos. El 40% de las cepas de suelo presentó multiresistencia (a tres o más grupos de antibióticos, el 30% de las de origen humano, el 14% de las de alimentos y el 5% de las de origen animal. Las altas tasas de resistencia encontradas podrían deberse al amplio uso de antibióticos como promotores de crecimiento de plantas y animales y esas cepas resistentes podrían actuar como reservorio de genes de resistencia que pueden transferirse entre bacterias de diversos ambientes.

  7. Immunoprophylactic strategies against enterotoxemia caused by Clostridium perfringens type D in goats Estratégias imunoprofiláticas contra enterotoxemia causada por Clostridium perfringens tipo D em caprinos

    Directory of Open Access Journals (Sweden)

    Josir Laine A. Veschi

    2006-03-01

    Full Text Available The serological response to an experimental vaccine against Clostridium perfringens type D enterotoxemia was evaluated in four groups of goats. Group 1 received colostrum from unvaccinated cows and no vaccine. Groups 2, 3 and 4 received colostrum from vaccinated cows. In addition, Groups 3 and 4 received a vaccine dose at 80 days of age, and Group 4 received a second vaccine dose at 120 days of age. Serum antibody levels were determined by ELISA in cows before and after calving, and in goats at 3, 80, 120 and 160 days of age. No significant difference in serum antibody levels was observed between vaccinated and unvaccinated cows, or between the four groups of goats evaluated at 3 days of life. Groups 3 and 4 presented mean antibody titers of 0.6 and 1.1 IU/ml, respectively, 40 days after first vaccination. The vaccine response of Group 4 was 1.8 IU/ml 40 days after the booster dose and was higher than that observed for Group 3 (0.2 IU/ml. Thus, in the proposed regimen the use of heterologous colostrum did not induce passive immunization in goat kids. However, first vaccination and a booster dose after 40 days triggered satisfactory antibody levels.Foi avaliada a resposta sorológica de vacina experimental contra a enterotoxemia em quatro grupos de caprinos. O Grupo 1 recebeu colostro de vacas não vacinadas e nenhuma dose de vacina. Os Grupos 2, 3 e 4 receberam colostro de vacas vacinadas, e uma dose de vacina aos 80 dias de idade nos Grupos 3 e 4. O Grupo 4 recebeu a segunda dose de vacina aos 120 dias de idade. Os níveis de anticorpos séricos foram avaliados pelo ELISA nas vacas antes e depois do parto e nos caprinos aos 3, 80, 120 e 160 dias de idade. Não houve diferença significativa nos níveis de anticorpos séricos das vacas vacinadas e não vacinadas, assim como entre os quatro grupos de caprinos avaliados aos três dias de vida. Os Grupos 3 e 4 apresentaram títulos médios de anticorpos de 0,6 UI/mL e 1,1 UI/mL, respectivamente

  8. Effects of Bacillus licheniformis on the growth performance and expression of lipid metabolism-related genes in broiler chickens challenged with Clostridium perfringens-induced necrotic enteritis.

    Science.gov (United States)

    Zhou, Mengjia; Zeng, Dong; Ni, Xueqin; Tu, Teng; Yin, Zhongqiong; Pan, Kangcheng; Jing, Bo

    2016-03-08

    Necrotic enteritis (NE), caused by Clostridium perfringens, has cost the poultry industry $2 billion in losses. This study aimed to investigate the effect of Bacillus licheniformis as dietary supplement on the growth, serum antioxidant status, and expression of lipid-metabolism genes of broiler chickens with C. perfringens-induced NE. A total of 240 one-day-old broilers were randomly grouped into four: a negative control, an NE experimental model (PC), chickens fed a diet supplemented with 30 % of fishmeal from day 14 onwards and challenged with coccidiosis vaccine (FC), and NE group supplied with feed containing 1.0 × 10(6) CFU/g B. licheniformis (BL). Body weight gain, feed conversion ratio, serum antioxidant status, and lipid-metabolism-gene expression were analyzed. In the PC group, FCR increased significantly whereas serum catalase and glutathione peroxidase activity decreased compared with NC group. Dietary B. licheniformis supplementation improved FCR and oxidative stress in experimental avian NE. Using Bacillus licheniformis as a direct-fed microbial (DFM) could also significantly upregulate catabolism-related genes, namely, peroxisome proliferator-activated receptor-α and carnitine palmitoyltransferase-1, in livers and changed the expression of lipid-anabolism genes. These results suggested that dietary B. licheniformis supplementation can enhance growth and antioxidant ability, as well as change the expression of genes related to fatty-acid synthesis and oxidation in the livers of NE-infected broilers.

  9. Necrotic enteritis locus 1 diguanylate cyclase and phosphodiesterase (cyclic-di-GMP) gene mutation attenuates virulence in an avian necrotic enteritis isolate of Clostridium perfringens.

    Science.gov (United States)

    Parreira, Valeria R; Ojha, Shivani; Lepp, Dion; Mehdizadeh Gohari, Iman; Zhou, Hongzhuan; Susta, Leonardo; Gong, Jianhua; Prescott, John F

    2017-09-01

    Necrotic enteritis (NE) caused by netB-positive strains of Clostridium perfringens is an important disease of intensively-reared broiler chickens. It is widely controlled by antibiotic use, but this practice that has come under increasing scrutiny and alternative approaches are required. As part of the search for alternative approaches over the last decade, advances have been made in understanding its pathogenesis but much remains to be understood and applied to the control of NE. The objective of this work was to assess the effect on virulence of mutation of the cyclic-di-GMP signaling genes present on the large pathogenicity locus (NELoc-1) in the tcp-encoding conjugative virulence plasmid, pNetB. For this purpose, the diguanylate cyclase (dgc) and phosphodiesterase (pde) genes were individually insertionally inactivated and the two mutants were subsequently complemented with their respective genes. Southern blotting showed that a single gene insertion was present. Mutation of either gene resulted in almost total attenuation of the mutants to cause NE in experimentally-infected broiler chickens, which was fully restored in each case by complementation of the respective mutated gene. Production of NetB-associated cytotoxicity for Leghorn male hepatoma (LMH) cells was unaffected in mutants. We conclude that the cyclic-di-GMP signaling system is important in controlling virulence in a NE C. perfringens strain and might be a target for control of the disease. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Comparative genome analysis of clostridium perfringens isolates from healthy and necrotic enteritis infected poultry and diseased pigs

    DEFF Research Database (Denmark)

    Ronco, Troels; Lyhs, Ulrike; Stegger, Marc

    2015-01-01

    to be important for the development of NE in chickens and piglets, respectively, while the role of these toxins is less well elucidated in diseased turkeys. Methods: We carried out comparative genomic analysis of 40 C. perfringens genomes from healthy and NE-suffering chickens and turkeys, and diseased pigs using......B, NELoc-1 and -3 seem to play an important role in the NE pathogenesis in chickens, whereas cpb2 is important in diseased pigs. • The VirSR two-component system is involved in regulating NE-associated virulence genes. • Conjugative plasmid genes are widely spread among C. perfringens. • WGS is a powerful...

  11. Impact of Clean-Label Antimicrobials and Nitrite Derived from Natural Sources on the Outgrowth of Clostridium perfringens during Cooling of Deli-Style Turkey Breast.

    Science.gov (United States)

    King, Amanda M; Glass, Kathleen A; Milkowski, Andrew L; Sindelar, Jeffrey J

    2015-05-01

    Organic acids and sodium nitrite have long been shown to provide antimicrobial activity during chilling of cured meat products. However, neither purified organic acids nor NaNO2 is permitted in products labeled natural and both are generally avoided in clean-label formulations; efficacy of their replacement is not well understood. Natural and clean-label antimicrobial alternatives were evaluated in both uncured and in alternative cured (a process that uses natural sources of nitrite) deli-style turkey breast to determine inhibition of Clostridium perfringens outgrowth during 15 h of chilling. Ten treatments of ground turkey breast (76% moisture, 1.2% salt) included a control and four antimicrobials: 1.0% tropical fruit extract, 0.7% dried vinegar, 1.0% cultured sugar-vinegar blend, and 2.0% lemon-vinegar blend. Each treatment was formulated without (uncured) and with nitrite (PCN; 50 ppm of NaNO2 from cultured celery juice powder). Treatments were inoculated with C. perfringens spores (three-strain mixture) to yield 2.5 log CFU/g. Individual 50-g portions were vacuum packaged, cooked to 71.1°C, and chilled from 54.4 to 26.7°C in 5 h and from 26.7 to 7.2°C in an additional 10 h. Triplicate samples were assayed for growth of C. perfringens at predetermined intervals by plating on tryptose-sulfite-cycloserine agar. Uncured control and PCN-only treatments allowed for 4.6- and 4.2-log increases at 15 h, respectively, and although all antimicrobial treatments allowed less outgrowth than uncured and PCN, the degree of inhibition varied. The 1.0% fruit extract and 1.0% cultured sugar-vinegar blend were effective at controlling populations at or below initial levels, whether or not PCN was included. Without PCN, 0.7% dried vinegar and 2.0% lemon-vinegar blend allowed for 2.0- and 2.5-log increases, respectively, and ∼1.5-log increases with PCN. Results suggest using clean-label antimicrobials can provide for safe cooling following the study parameters, and greater

  12. The application of rumen simulation technique (RUSITEC for studying dynamics of the bacterial community and metabolome in rumen fluid and the effects of a challenge with Clostridium perfringens.

    Directory of Open Access Journals (Sweden)

    Stefanie U Wetzels

    Full Text Available The rumen simulation technique (RUSITEC is a well-established semicontinuous in vitro model for investigating ruminal fermentation; however, information on the stability of the ruminal bacterial microbiota and metabolome in the RUSITEC system is rarely available. The availability of high resolution methods, such as high-throughput sequencing and metabolomics improve our knowledge about the rumen microbial ecosystem and its fermentation processes. Thus, we used Illumina MiSeq 16S rRNA amplicon sequencing and a combination of direct injection mass spectrometry with a reverse-phase LC-MS/MS to evaluate the dynamics of the bacterial community and the concentration of several metabolites in a RUSITEC experiment as a function of time and in response to a challenge with a pathogenic Clostridium perfringens (C. perfringens strain. After four days of equilibration, samples were collected on days 5, 6, 7, 10, 12 and 15 of the steady-state and experimental period. From a total of six fermenters, three non-infected fermenters were used for investigating time-dependent alterations; three fermenters were incubated with C. perfringens and compared with the non-infected vessels at days 10, 12 and 15. Along the time-line, there was no statistically significant change of the overall bacterial community, however, some phylotypes were enriched at certain time points. A decrease in Fibrobacter and Elusimicrobia over time was followed by an increase in Firmicutes and Actinobacteria. In contrast, classical fermentation measurements such as pH, redox potential, NH3-N, short chain fatty acids and the concentrations of metabolites determined by metabolomics (biogenic amines, hexoses and amino acids remained stable throughout the experiment. In response to C. perfringens addition the concentrations of several amino acids increased. Although the overall bacterial community was not altered here either, some minor changes such as an enrichment of Synergistetes and

  13. Clostridium perfringens challenge and dietary fat type affect broiler chicken performance and fermentation in the gastrointestinal tract

    DEFF Research Database (Denmark)

    Jozefiak, D; Kieronczyk, B; Rawski, M

    2014-01-01

    fat and lard. In Experiment 2, birds were fed diets containing rapeseed oil, coconut oil, beef tallow and palm oil. In both experiments, the birds were either not challenged or challenged with a mixture of three C. perfringens type A strains. Irrespective of the fat type present in the diet, C...... were carried out, each including 480-day-old male broilers (Ross 308), which were randomly distributed to eight experimental groups using six replicate pens per treatment and 10 birds per pen. In Experiment 1, birds were fed diets containing soybean oil, palm kernel fatty acid distillers, rendered pork...... of animal fats tended to improve final BW to a greater extent compared with the inclusion of unsaturated vegetable oils. In Experiment 2, irrespective of the dietary fat type present in the diet, C. perfringens challenge significantly impaired feed conversion ratio in the period from 14 to 28 days (1.63 v...

  14. Cyclic Di-GMP Binding by an Assembly ATPase (PilB2) and Control of Type IV Pilin Polymerization in the Gram-Positive Pathogen Clostridium perfringens.

    Science.gov (United States)

    Hendrick, William A; Orr, Mona W; Murray, Samantha R; Lee, Vincent T; Melville, Stephen B

    2017-05-15

    The Gram-positive pathogen Clostridium perfringens possesses type IV pili (TFP), which are extracellular fibers that are polymerized from a pool of pilin monomers in the cytoplasmic membrane. Two proteins that are essential for pilus functions are an assembly ATPase (PilB) and an inner membrane core protein (PilC). Two homologues each of PilB and PilC are present in C. perfringens , called PilB1/PilB2 and PilC1/PilC2, respectively, along with four pilin proteins, PilA1 to PilA4. The gene encoding PilA2, which is considered the major pilin based on previous studies, is immediately downstream of the pilB2 and pilC2 genes. Purified PilB2 had ATPase activity, bound zinc, formed hexamers even in the absence of ATP, and bound the second messenger molecule cyclic di-GMP (c-di-GMP). Circular dichroism spectroscopy of purified PilC2 indicated that it retained its predicted degree of alpha-helical secondary structure. Even though no direct interactions between PilB2 and PilC2 could be detected in vivo or in vitro even in the presence of c-di-GMP, high levels of expression of a diguanylate cyclase from C. perfringens (CPE1788) stimulated polymerization of PilA2 in a PilB2- and PilC2-dependent manner. These results suggest that PilB2 activity is controlled by c-di-GMP levels in vivo but that PilB2-PilC2 interactions are either transitory or of low affinity, in contrast to results reported previously from in vivo studies of the PilB1/PilC1 pair in which PilC1 was needed for polar localization of PilB1. This is the first biochemical characterization of a c-di-GMP-dependent assembly ATPase from a Gram-positive bacterium. IMPORTANCE Type IV pili (TFP) are protein fibers involved in important bacterial functions, including motility, adherence to surfaces and host cells, and natural transformation. All clostridia whose genomes have been sequenced show evidence of the presence of TFP. The genetically tractable species Clostridium perfringens was used to study proteins involved in

  15. Optimization of culture conditions to improve the expression level of beta1–epsilon toxin of Clostridium perfringens type B in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Chuwen Lin

    2016-03-01

    Full Text Available The detoxified beta1–epsilon (β1–ϵ toxin protein of Clostridium perfringens type B provides protection from C. perfringens types B, C and D infections. Acetate is the primary by-product from the cell growth and expression of β1–ϵ protein. In the present study, the effects of pH and dissolved oxygen (DO on the expression of β1--ϵ protein were investigated. Two-stage pH and DO control strategies were developed for the expression of β1–ϵ protein. The obtained results indicated that higher cell density and concentration of β1--ϵ protein, and lower accumulation of acetate were obtained when pH was maintained at a constant level of 6.5 (0–6 h and 7.0 (6–16 h, and the DO level was maintained at 60% (0–6 h and 30% (6–16 h. Furthermore, the impact of intermittent, DO feedback, pH feedback and glucose-stat feeding on the expression of β1–ϵ protein were studied. By using the DO feedback feeding, combined with the stage control of pH (6.5 for 0–6 h, 7.0 for 6–16 h and DO (60% for 0–6 h, 30% for 6–16 h, the highest cell density of 2.045 (absorbance at 600 nm and a β1–ϵ protein concentration of 63.24 mg/L were obtained, and the accumulation of acetate decreased to 0.872 g/L.

  16. Use of single-enzyme amplified fragment length polymorphism for typing Clostridium perfringens isolated from diarrheic piglets Uso do polimorfismo do comprimento de fragmentos amplificados para tipagem de Clostridium perfringens isolados de suínos com diarréia

    Directory of Open Access Journals (Sweden)

    Luciane Tieko Shinya

    2006-09-01

    Full Text Available Clostridium perfringens is an important pathogen in human and veterinary medicine. In swine, the agent is responsible for necrotic enteritis and enterotoxemia characterized by diarrhea, weight loss, delayed development and, in some cases, death. In the present study amplified fragment length polymorphism analyses (AFLP was used to characterize 54 C. perfringens strains isolated from swine presenting diarrhea. Analysis of the results showed 29 distinct profiles with discriminatory index equal to 0.97. Partial correlation between the origin of the isolates and groups was drawn, and correlation was possible in only 18.5% of the samples. Characterization of the strains in biotypes (A, B, C, D and E, production of beta-2 toxin and enterotoxin were performed by means of the polymerase chain reaction (PCR. Biotypes A, C and D were observed among the strains analyzed. All samples were positive for presence of the gene encoding beta-2 toxin and negative for the gene encoding enterotoxin. AFLP have shown to be a simple, fast, low cost method with high discriminative power and good reproducibility, presenting a great potential in epidemiological studies involving C. perfringens strains of animal origin.Clostridium perfringens é um importante agente infeccioso em medicina veterinária e humana. Em suínos, o agente é responsável pela enterite necrótica e enterotoxemia, caracterizadas por diarréia, perda de peso, atraso no desenvolvimento e morte. No presente estudo foi utilizado o polimorfismo do comprimento de fragmentos amplificados (AFLP, para caracterizar 54 isolados de C. perfringens obtidos de suínos com diarréia. A análise dos resultados do AFLP demonstrou 29 perfis distintos com índice discriminatório igual a 0,97. A correlação entre a origem dos isolados e os agrupamentos obtidos foi parcial, sendo apenas possível a correlação total de 18,5% das amostras estudadas. A caracterização das cepas em biotipos (A, B, C, D e E, produ

  17. Release of Glycoprotein (GP1 from the Tegumental Surface of Taenia solium by Phospholipase C from Clostridium perfringens Suggests a Novel Protein-Anchor to Membranes

    Directory of Open Access Journals (Sweden)

    Abraham Landa

    2010-01-01

    Full Text Available In order to explore how molecules are linked to the membrane surface in larval Taenia solium, whole cysticerci were incubated in the presence of phospholipase C from Clostridium perfringens (PLC. Released material was collected and analyzed in polyacrylamide gels with sodium dodecyl sulfate. Two major bands with apparent molecular weights of 180 and 43 kDa were observed. Western blot of released material and localization assays in cysticerci tissue sections using antibodies against five known surface glycoproteins of T. solium cysticerci indicated that only one, previously called GP1, was released. Similar localization studies using the lectins wheat-germ-agglutinin and Concanavalin A showed that N-acetyl-D-glucosamine, N-acetylneuraminic, sialic acid, αmethyl-D-mannoside, D-manose/glucose, and N-acetyl-D-glucosamine residues are abundantly present on the surface. On the other hand, we find that treatment with PLC releases molecules from the surface; they do not reveal Cross Reacting Determinant (CRD, suggesting a novel anchor to the membrane for the glycoprotein GP1.

  18. Evaluatie van de membraanfiltratiemethode op mCP-agar voor bepaling van sporen van Clostridium perfringens in water

    NARCIS (Netherlands)

    Schets FM; Medema GJ; LWL

    1995-01-01

    Current Dutch and European drinking water standards include criteria for spores of sulphite reducing clostridia. This has some inherent disadvantages. The reproducibility of the enumeration method for spores of sulphite reducing clostridia (SSRC) in Sulphite Cycloserine Agar (SCA) is poor. Some

  19. Padronização da titulação da toxina épsilon de Clostridium perfringens tipo D em linhagem contínua de células como alternativa ao bioensaio animal Standardization of the titration of the epsilon toxin of Clostridium perfringens type D in cell line as an alternative to animal bioassay

    Directory of Open Access Journals (Sweden)

    Milton Formiga Souza Júnior

    2010-03-01

    Full Text Available Enterotoxemia, também chamada de doença do rim pulposo, doença que acomete os ruminantes domésticos, é causada pela ação da toxina épsilon produzida pelo Clostridium perfringens tipo D, um anaeróbio comumente isolado do solo e das fezes de animais sadios. O método tradicional de diagnóstico baseia-se na detecção e classificação dessa exotoxina no conteúdo intestinal por meio da soroneutralização em camundongos. Com isso, o objetivo deste estudo foi padronizar um teste para detecção e titulação dessa toxina in vitro e compará-lo ao fenômeno in vivo. Para isso, uma partida de toxina épsilon de Clostridium perfringens tipo D foi titulada em camundongos e em várias linhagens contínuas de células. Após a determinação da linhagem celular mais sensível, realizaram-se ensaios de titulação in vitro de diluições de uma partida de toxina, comparando-os com os títulos in vivo conhecidos. Os resultados foram agrupados, e foi desenvolvida a equação matemática que melhor adaptou-se aos intervalos trabalhados. A linhagem MDCK, além de mais sensível, demonstrou que o fenômeno observado in vitro pode ser expresso por meio da equação matemática que apresenta uma correlação de 98,33%, com a dose mínima mortal determinada in vivo. Portanto, a linhagem MDCK permite titular a toxina épsilon de C. perfringens tipo D de forma específica e sensível, além de ser uma técnica prática, rápida e que dispensa o uso de animais.Enterotoxemia (also called pulpy kidney disease is an enteric disease, that affect ruminants, produced by epsilon toxin from Clostridium perfringens type D, an anaerobic commonly isolated from soil and feces of healthy animals. The diagnostic is based on detection of this exotoxin in the intestinal content by soroneutralization in mice. Therefore, this study aimed to standardize a test for detection and titration of the toxin in vitro, and compare it with the phenomenon in vivo. A volume of epsilon

  20. Growth of non-toxigenic Clostridium botulinum mutant LNT01 in cooked beef: One-step kinetic analysis and comparison with C. sporogenes and C. perfringens.

    Science.gov (United States)

    Huang, Lihan

    2018-05-01

    The objective of this study was to investigate the growth kinetics of Clostridium botulinum LNT01, a non-toxigenic mutant of C. botulinum 62A, in cooked ground beef. The spores of C. botulinum LNT01 were inoculated to ground beef and incubated anaerobically under different temperature conditions to observe growth and develop growth curves. A one-step kinetic analysis method was used to analyze the growth curves simultaneously to minimize the global residual error. The data analysis was performed using the USDA IPMP-Global Fit, with the Huang model as the primary model and the cardinal parameters model as the secondary model. The results of data analysis showed that the minimum, optimum, and maximum growth temperatures of this mutant are 11.5, 36.4, and 44.3 °C, and the estimated optimum specific growth rate is 0.633 ln CFU/g per h, or 0.275 log CFU/g per h. The maximum cell density is 7.84 log CFU/g. The models and kinetic parameters were validated using additional isothermal and dynamic growth curves. The resulting residual errors of validation followed a Laplace distribution, with about 60% of the residual errors within ±0.5 log CFU/g of experimental observations, suggesting that the models could predict the growth of C. botulinum LNT01 in ground beef with reasonable accuracy. Comparing with C. perfringens, C. botulinum LNT01 grows at much slower rates and with much longer lag times. Its growth kinetics is also very similar to C. sporogenes in ground beef. The results of computer simulation using kinetic models showed that, while prolific growth of C. perfringens may occur in ground beef during cooling, no growth of C. botulinum LNT01 or C. sporogenes would occur under the same cooling conditions. The models developed in this study may be used for prediction of the growth and risk assessments of proteolytic C. botulinum in cooked meats. Published by Elsevier Ltd.

  1. 1H, 15N and 13C backbone and side-chain resonance assignments of a family 32 carbohydrate-binding module from the Clostridium perfringens NagH.

    Science.gov (United States)

    Grondin, Julie M; Chitayat, Seth; Ficko-Blean, Elizabeth; Boraston, Alisdair B; Smith, Steven P

    2012-10-01

    The Gram-positive anaerobe Clostridium perfringens is an opportunistic bacterial pathogen that secretes a battery of enzymes involved in glycan degradation. These glycoside hydrolases are thought to be involved in turnover of mucosal layer glycans, and in the spread of major toxins commonly associated with the development of gastrointestinal diseases and gas gangrene in humans. These enzymes employ multi-modularity and carbohydrate-binding function to degrade extracellular eukaryotic host sugars. Here, we report the full (1)H, (15)N and (13)C chemical shift resonance assignments of the first family 32 carbohydrate-binding module from NagH, a secreted family 84 glycoside hydrolase.

  2. Challenging the roles of CD44 and lipolysis stimulated lipoprotein receptor in conveying Clostridium perfringens iota toxin cytotoxicity in breast cancer.

    Science.gov (United States)

    Fagan-Solis, Katerina D; Reaves, Denise K; Rangel, M Cristina; Popoff, Michel R; Stiles, Bradley G; Fleming, Jodie M

    2014-07-02

    Translational exploration of bacterial toxins has come to the forefront of research given their potential as a chemotherapeutic tool. Studies in select tissues have demonstrated that Clostridium perfringens iota toxin binds to CD44 and lipolysis stimulated lipoprotein receptor (LSR) cell-surface proteins. We recently demonstrated that LSR expression correlates with estrogen receptor positive breast cancers and that LSR signaling directs aggressive, tumor-initiating cell behaviors. Herein, we identify the mechanisms of iota toxin cytotoxicity in a tissue-specific, breast cancer model with the ultimate goal of laying the foundation for using iota toxin as a targeted breast cancer therapy. In vitro model systems were used to determine the cytotoxic effect of iota toxin on breast cancer intrinsic subtypes. The use of overexpression and knockdown technologies confirmed the roles of LSR and CD44 in regulating iota toxin endocytosis and induction of cell death. Lastly, cytotoxicity assays were used to demonstrate the effect of iota toxin on a validated set of tamoxifen resistant breast cancer cell lines. Treatment of 14 breast cancer cell lines revealed that LSR+/CD44- lines were highly sensitive, LSR+/CD44+ lines were slightly sensitive, and LSR-/CD44+ lines were resistant to iota cytotoxicity. Reduction in LSR expression resulted in a significant decrease in toxin sensitivity; however, overexpression of CD44 conveyed toxin resistance. CD44 overexpression was correlated with decreased toxin-stimulated lysosome formation and decreased cytosolic levels of iota toxin. These findings indicated that expression of CD44 drives iota toxin resistance through inhibition of endocytosis in breast cancer cells, a role not previously defined for CD44. Moreover, tamoxifen-resistant breast cancer cells exhibited robust expression of LSR and were highly sensitive to iota-induced cytotoxicity. Collectively, these data are the first to show that iota toxin has the potential to be an

  3. Avaliação da capacidade probiótica de uma linhagem de Ruminococcus gnavus da microbiota fecal de seres humanos contra Clostridium perfringens

    Directory of Open Access Journals (Sweden)

    Flávio Henrique Ferreira Barbosa

    2011-03-01

    Full Text Available Normal 0 21 false false false PT-BR X-NONE X-NONE MicrosoftInternetExplorer4 Probióticos são microrganismos utilizados com o propósito de beneficiar a saúde do hospedeiro, seja na prevenção ou tratamento de doenças. Este trabalho teve como objetivo avaliar uma cultura de Ruminococcus gnavus quanto ao seu efeito probiótico frente a um alvo patogênico in vivo por meio de avaliação histopatológica e perfil de hidrofobicidade da parede celular. A linhagem de R. gnavus foi isolada da microbiota fecal dominante de um adulto sadio. Uma amostra padrão de Clostridium perfringens foi utilizada como patógeno para o desafio por via oral de camundongos previamente monoassociados com R. gnavus. Camundongos suíços NIH isentos de germes foram usados como modelo animal. Nos resultados dos testes de adesão da superfície celular do microrganismo estudado, ficou constatado que a espécie R. gnavus possui uma parede celular mais hidrofóbica e ácida, sinalizando boa probabilidade de adesão ao epitélio intestinal. A análise histológica demonstrou que a monoassociação com R. gnavus não promoveu nenhuma alteração morfológica dos órgãos analisados (intestinos, baço e fígado, e apresentou efeito protetor, constatado no ceco e no fígado de camundongos gnotobióticos. Em suma, os resultados reforçam que R. gnavus possui características protetoras desejáveis no que tange a elaboração de futuros probióticos.

  4. Development and application of a new method for specific and sensitive enumeration of spores of nonproteolytic Clostridium botulinum types B, E, and F in foods and food materials.

    Science.gov (United States)

    Peck, Michael W; Plowman, June; Aldus, Clare F; Wyatt, Gary M; Izurieta, Walter Penaloza; Stringer, Sandra C; Barker, Gary C

    2010-10-01

    The highly potent botulinum neurotoxins are responsible for botulism, a severe neuroparalytic disease. Strains of nonproteolytic Clostridium botulinum form neurotoxins of types B, E, and F and are the main hazard associated with minimally heated refrigerated foods. Recent developments in quantitative microbiological risk assessment (QMRA) and food safety objectives (FSO) have made food safety more quantitative and include, as inputs, probability distributions for the contamination of food materials and foods. A new method that combines a selective enrichment culture with multiplex PCR has been developed and validated to enumerate specifically the spores of nonproteolytic C. botulinum. Key features of this new method include the following: (i) it is specific for nonproteolytic C. botulinum (and does not detect proteolytic C. botulinum), (ii) the detection limit has been determined for each food tested (using carefully structured control samples), and (iii) a low detection limit has been achieved by the use of selective enrichment and large test samples. The method has been used to enumerate spores of nonproteolytic C. botulinum in 637 samples of 19 food materials included in pasta-based minimally heated refrigerated foods and in 7 complete foods. A total of 32 samples (5 egg pastas and 27 scallops) contained spores of nonproteolytic C. botulinum type B or F. The majority of samples contained <100 spores/kg, but one sample of scallops contained 444 spores/kg. Nonproteolytic C. botulinum type E was not detected. Importantly, for QMRA and FSO, the construction of probability distributions will enable the frequency of packs containing particular levels of contamination to be determined.

  5. The effect of Artemisia annua on broiler performance, on intestinal microbiota and on the course of a Clostridium perfringens infection applying a necrotic enteritis disease model

    DEFF Research Database (Denmark)

    Engberg, Ricarda M; Grevsen, Kai; Ivarsen, Elise

    2012-01-01

    The aerial parts of the plant Artemisia annua contain essential oils having antimicrobial properties against Clostridium perfringens Type A, the causal agent for necrotic enteritis in broilers. In two experiments, the influence of increasing dietary concentrations of dried A. annua leaves (0, 5, 10...... and 20 g/kg) and n-hexane extract from fresh A. annua leaves (0, 125, 250 and 500 mg/kg) on broiler performance was investigated. Dried plant material decreased feed intake and body weight in a dose-dependent manner, and 10 and 20 g/kg diet tended to improve the feed conversion ratio. The n...... the effect of the dietary addition of dried A. annua leaves (10 g/kg on top) or n-hexane extract of A. annua (250 mg/kg) on the severity of the disease in broilers. The addition of n-hexane extract reduced the intestinal C. perfringens numbers and the severity of the disease-related small intestinal lesions...

  6. Quantitative Detection of Clostridium perfringens in Broiler Chickens by Real-Time PCR Targeting the Alpha-Toxin Gene

    DEFF Research Database (Denmark)

    Abildgaard, Lone; Engberg, Ricarda M.; Schramm, Andreas

    2006-01-01

    was developed by sequencing the α-toxin gene from ~60 strains of C. perfringens, isolated from diseased as well as healthy broilers. For its application to the chicken gastrointestinal tract (i.e., ileum), DNA extraction efficiency and potential inhibition of the real-time PCR process by ileum content...

  7. Claudin-4 Overexpression in Epithelial Ovarian Cancer Is Associated with Hypomethylation and Is a Potential Target for Modulation of Tight Junction Barrier Function Using a C-Terminal Fragment of Clostridium perfringens Enterotoxin

    Directory of Open Access Journals (Sweden)

    Babak Litkouhi

    2007-04-01

    Full Text Available BACKGROUND: Claudin-4, a tight junction (TJ protein and receptor for the C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE, is overexpressed in epithelial ovarian cancer (EOC. Previous research suggests DNA methylation is a mechanism for claudin-4 overexpression in cancer and that C-CPE acts as an absorption-enhancing agent in claudin-4expressing cells. We sought to correlate claudin-4 overexpression in EOC with clinical outcomes and TJ barrier function, investigate DNA methylation as a mechanism for overexpression, and evaluate the effect of C-CPE on the TJ. METHODS: Claudin-4 expression in EOC was quantified and correlated with clinical outcomes. Claudin-4 methylation status was determined, and claudin-4-negative cell lines were treated with a demethylating agent. Electric cell-substrate impedance sensing was used to calculate junctional (paracellular resistance (Rb in EOC cells after claudin-4 silencing and after C-CPE treatment. RESULTS: Claudin4 overexpression in EOC does not correlate with survival or other clinical endpoints and is associated with hypomethylation. Claudin-4 overexpression correlates with Rb and C-CPE treatment of EOC cells significantly decreased Rb in a dose- and claudin-4-dependent noncytotoxic manner. CONCLUSIONS: C-CPE treatment of EOC cells leads to altered TJ function. Further research is needed to determine the potential clinical applications of C-CPE in EOC drug delivery strategies.

  8. Development and Application of a New Method for Specific and Sensitive Enumeration of Spores of Nonproteolytic Clostridium botulinum Types B, E, and F in Foods and Food Materials ▿

    Science.gov (United States)

    Peck, Michael W.; Plowman, June; Aldus, Clare F.; Wyatt, Gary M.; Penaloza Izurieta, Walter; Stringer, Sandra C.; Barker, Gary C.

    2010-01-01

    The highly potent botulinum neurotoxins are responsible for botulism, a severe neuroparalytic disease. Strains of nonproteolytic Clostridium botulinum form neurotoxins of types B, E, and F and are the main hazard associated with minimally heated refrigerated foods. Recent developments in quantitative microbiological risk assessment (QMRA) and food safety objectives (FSO) have made food safety more quantitative and include, as inputs, probability distributions for the contamination of food materials and foods. A new method that combines a selective enrichment culture with multiplex PCR has been developed and validated to enumerate specifically the spores of nonproteolytic C. botulinum. Key features of this new method include the following: (i) it is specific for nonproteolytic C. botulinum (and does not detect proteolytic C. botulinum), (ii) the detection limit has been determined for each food tested (using carefully structured control samples), and (iii) a low detection limit has been achieved by the use of selective enrichment and large test samples. The method has been used to enumerate spores of nonproteolytic C. botulinum in 637 samples of 19 food materials included in pasta-based minimally heated refrigerated foods and in 7 complete foods. A total of 32 samples (5 egg pastas and 27 scallops) contained spores of nonproteolytic C. botulinum type B or F. The majority of samples contained <100 spores/kg, but one sample of scallops contained 444 spores/kg. Nonproteolytic C. botulinum type E was not detected. Importantly, for QMRA and FSO, the construction of probability distributions will enable the frequency of packs containing particular levels of contamination to be determined. PMID:20709854

  9. Enumerating submultisets of multisets

    NARCIS (Netherlands)

    Hage, J.

    2001-01-01

    In this paper we consider the problem of enumerating the submultisets of a multiset, in which each element has equal multiplicity. The crucial property is that consecutive submultisets in this listing differ one in the cardinality of only one of the elements. This is a generalization to k-ary

  10. Sporadic diarrhoea due to Clostridium perfringens in children aged ...

    African Journals Online (AJOL)

    Fred

    2004-07-25

    Jul 25, 2004 ... After overnight incubation, the total viable count was done by counting the colonies in each dilution series using the Miles and. Misra technique (Miles and Misra, 1938.). The EYM plates were also examined for detection of lecithinase, lipase and proteolytic enzyme production (Barrow and Feltham, 1993).

  11. Enumeration of fungi in barley

    CSIR Research Space (South Africa)

    Rabie, CJ

    1997-04-01

    Full Text Available Estimation of fungal contamination of barley grain is important as certain fungi can proliferate during the malting process. The following factors which may affect the enumeration of fungi were evaluated: dilution versus direct plating, pre...

  12. Analysis and enumeration algorithms for biological graphs

    CERN Document Server

    Marino, Andrea

    2015-01-01

    In this work we plan to revise the main techniques for enumeration algorithms and to show four examples of enumeration algorithms that can be applied to efficiently deal with some biological problems modelled by using biological networks: enumerating central and peripheral nodes of a network, enumerating stories, enumerating paths or cycles, and enumerating bubbles. Notice that the corresponding computational problems we define are of more general interest and our results hold in the case of arbitrary graphs. Enumerating all the most and less central vertices in a network according to their eccentricity is an example of an enumeration problem whose solutions are polynomial and can be listed in polynomial time, very often in linear or almost linear time in practice. Enumerating stories, i.e. all maximal directed acyclic subgraphs of a graph G whose sources and targets belong to a predefined subset of the vertices, is on the other hand an example of an enumeration problem with an exponential number of solutions...

  13. Clostridium difficile

    NARCIS (Netherlands)

    Bakker, Guido J.; Nieuwdorp, Max

    2017-01-01

    Clostridium difficileinfection (CDI), inflammatory bowel disease (IBD), and metabolic diseases such as obesity, type 2 diabetes (T2D), and nonalcoholic steatohepatitis (NASH). Fecal microbiota transplantation (FMT) is currently tested as a therapeutic option in various diseases and can also help to

  14. Prevalence of C. botulinum and C. perfringens spores in food products available on Polish market

    Directory of Open Access Journals (Sweden)

    Grenda Tomasz

    2017-09-01

    Full Text Available Introduction: The aim of this study was to evaluate the prevalence of Clostridium botulinum and Clostridium perfringens in food samples purchased from Polish producers. Material and Methods: The analyses were performed on 260 food samples collected in Lublin and Subcarpathian regions: 56 of smoked meat, 21 of pork meat, 20 of dairy products, 26 of vegetable and fruit preserves, 40 of ready-to-eat meals, 27 of fish preserves, and 70 of honey collected directly from apiaries. Results: C. botulinum strains were isolated from 2.3% (6/260 of samples and the isolates were classified as toxin types A (4/260 and B (2/260. C. perfringens strains were isolated from 14% (37/260 of samples. All the isolates were classified as toxin type A, 28 of them were able also to produce α toxin and 9 - β2 toxin. Conclusion: On the basis of the obtained results it could be suggested that risk assessment, especially regarding the entire honey harvesting process, should be provided in order to ensure the microbiological safety of the products to be consumed by infants and people with a weakened immune system.

  15. Almost computably enumerable families of sets

    International Nuclear Information System (INIS)

    Kalimullin, I Sh

    2008-01-01

    An almost computably enumerable family that is not Φ'-computably enumerable is constructed. Moreover, it is established that for any computably enumerable (c.e.) set A there exists a family that is X-c.e. if and only if the set X is not A-computable. Bibliography: 5 titles.

  16. Antibacterial activity against Clostridium genus and antiradical activity of the essential oils from different origin.

    Science.gov (United States)

    Kačániová, Miroslava; Vukovič, Nenad; Horská, Elena; Salamon, Ivan; Bobková, Alica; Hleba, Lukáš; Fiskelová, Martina; Vatľák, Alexander; Petrová, Jana; Bobko, Marek

    2014-01-01

    In the present study, the antimicrobial and antiradical activities of 15 essential oils were investigated. The antimicrobial activities were determined by using agar disc diffusion and broth microdilution methods against Clostridium genus and antioxidant properties of essential oils by testing their scavenging effect on DPPH radicals activities. We determined the antibacterial activity of Clostridium butyricum, Clostridium hystoliticum, Clostridium intestinale, Clostridium perfringens and Clostridium ramosum. We obtained the original commercial essential oils samples of Lavandula angustifolia, Carum carvi, Pinus montana, Mentha piperita, Foeniculum vulgare Mill., Pinus sylvestris, Satureia montana, Origanum vulgare L. (2 samples), Pimpinella anisum, Rosmarinus officinalis L., Salvia officinalis L., Abies alba Mill., Chamomilla recutita L. Rausch and Thymus vulgaris L. produced in Slovakia (Calendula a.s., Nova Lubovna, Slovakia). The results of the disk diffusion method showed very high essential oils activity against all tested strains of microorganisms. The best antimicrobial activity against C. butyricum was found at Pimpinella anisum, against C. hystoliticum was found at Pinus sylvestris, against C. intestinale was found at Satureia hortensis L., against C. perfringens was found at Origanum vulgare L. and against C. ramosum was found at Pinus sylvestris. The results of broth microdilution assay showed that none of the essential oils was active against C. hystoliticum. The best antimicrobial activity against C. butyricum was found at Abies alba Mill., against C. intestinale was found at Abies alba Mill., against C. perfringens was found at Satureia montana and against C. ramosum was found at Abius alba and Carum carvi. Antioxidant DPPH radical scavenging activity was determined at several solutions of oil samples (50 μL.mL(-1)-0.39 μL.mL(-1)) and the best scavenging effect for the highest concentration (50 μL.mL(-1)) was observed. The antioxidant properties

  17. In vitro inhibition of Clostridium difficile and Clostridium perfringens by commercial probiotic strains

    DEFF Research Database (Denmark)

    Schoster, A.; Kokotovic, Branko; Permin, Anders

    2013-01-01

    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...

  18. Application of hyperplane arrangements to weight enumeration

    NARCIS (Netherlands)

    Jurrius, R.P.M.J.; Pellikaan, G.R.

    2014-01-01

    Many research in coding theory is focussed on linear error-correcting codes. Since these codes are subspaces, linear algebra plays a prominent role in studying them. An important polynomial invariant of linear error-correcting codes is the (extended) weight enumerator. The weight enumerator gives

  19. The Clostridium sporulation programs: diversity and preservation of endospore differentiation.

    Science.gov (United States)

    Al-Hinai, Mohab A; Jones, Shawn W; Papoutsakis, Eleftherios T

    2015-03-01

    Bacillus and Clostridium organisms initiate the sporulation process when unfavorable conditions are detected. The sporulation process is a carefully orchestrated cascade of events at both the transcriptional and posttranslational levels involving a multitude of sigma factors, transcription factors, proteases, and phosphatases. Like Bacillus genomes, sequenced Clostridium genomes contain genes for all major sporulation-specific transcription and sigma factors (spo0A, sigH, sigF, sigE, sigG, and sigK) that orchestrate the sporulation program. However, recent studies have shown that there are substantial differences in the sporulation programs between the two genera as well as among different Clostridium species. First, in the absence of a Bacillus-like phosphorelay system, activation of Spo0A in Clostridium organisms is carried out by a number of orphan histidine kinases. Second, downstream of Spo0A, the transcriptional and posttranslational regulation of the canonical set of four sporulation-specific sigma factors (σ(F), σ(E), σ(G), and σ(K)) display different patterns, not only compared to Bacillus but also among Clostridium organisms. Finally, recent studies demonstrated that σ(K), the last sigma factor to be activated according to the Bacillus subtilis model, is involved in the very early stages of sporulation in Clostridium acetobutylicum, C. perfringens, and C. botulinum as well as in the very late stages of spore maturation in C. acetobutylicum. Despite profound differences in initiation, propagation, and orchestration of expression of spore morphogenetic components, these findings demonstrate not only the robustness of the endospore sporulation program but also the plasticity of the program to generate different complex phenotypes, some apparently regulated at the epigenetic level. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  20. Ensemble Weight Enumerators for Protograph LDPC Codes

    Science.gov (United States)

    Divsalar, Dariush

    2006-01-01

    Recently LDPC codes with projected graph, or protograph structures have been proposed. In this paper, finite length ensemble weight enumerators for LDPC codes with protograph structures are obtained. Asymptotic results are derived as the block size goes to infinity. In particular we are interested in obtaining ensemble average weight enumerators for protograph LDPC codes which have minimum distance that grows linearly with block size. As with irregular ensembles, linear minimum distance property is sensitive to the proportion of degree-2 variable nodes. In this paper the derived results on ensemble weight enumerators show that linear minimum distance condition on degree distribution of unstructured irregular LDPC codes is a sufficient but not a necessary condition for protograph LDPC codes.

  1. Clostridium difficile toxin CDT induces formation of microtubule-based protrusions and increases adherence of bacteria.

    Directory of Open Access Journals (Sweden)

    Carsten Schwan

    2009-10-01

    Full Text Available Clostridium difficile causes antibiotic-associated diarrhea and pseudomembranous colitis by production of the Rho GTPase-glucosylating toxins A and B. Recently emerging hypervirulent Clostridium difficile strains additionally produce the binary ADP-ribosyltransferase toxin CDT (Clostridium difficile transferase, which ADP-ribosylates actin and inhibits actin polymerization. Thus far, the role of CDT as a virulence factor is not understood. Here we report by using time-lapse- and immunofluorescence microscopy that CDT and other binary actin-ADP-ribosylating toxins, including Clostridium botulinum C2 toxin and Clostridium perfringens iota toxin, induce redistribution of microtubules and formation of long (up to >150 microm microtubule-based protrusions at the surface of intestinal epithelial cells. The toxins increase the length of decoration of microtubule plus-ends by EB1/3, CLIP-170 and CLIP-115 proteins and cause redistribution of the capture proteins CLASP2 and ACF7 from microtubules at the cell cortex into the cell interior. The CDT-induced microtubule protrusions form a dense meshwork at the cell surface, which wrap and embed bacterial cells, thereby largely increasing the adherence of Clostridia. The study describes a novel type of microtubule structure caused by less efficient microtubule capture and offers a new perspective for the pathogenetic role of CDT and other binary actin-ADP-ribosylating toxins in host-pathogen interactions.

  2. Clostridium botulinum type E occurs and grows in the alga Cladophora glomerata

    Science.gov (United States)

    Byappanahalli, M.N.; Whitman, R.L.

    2009-01-01

    In recent years, massive avian die-offs from Clostridium botulinum type E infection have occurred in the Sleeping Bear Dunes National Lakeshore (SLBE) area of Lake Michigan. These outbreaks have been coincidental with massive blooms of the green algae Cladophora, mostly Cladophora glomerata. We tested the hypothesis that Clostridium botulinum type E can grow under suitable conditions in these algal mats. In a lab mesocosm study, Cladophora from four outbreak-impacted beaches from SLBE were compared with four unimpacted beaches in the Milwaukee–Racine area for bontE gene of Clostridium botulinum. Frequency of the bontE gene was higher after incubation (25 °C for up to 6 weeks) of Cladophora from impacted vs. the unimpacted area. Since no type E gene was detected initially in Cladophora from any of the eight locations, we infer that the increased occurrence of type E gene arose from spore germination or vegetative Clostridium growth within the existing algal mats of SLBE. Moreover, we found that the congener Clostridium perfringens readily grows in mesocosms containing Cladophora.

  3. Clostridium Difficile Infections

    Science.gov (United States)

    Clostridium difficile (C. difficile) is a bacterium that causes diarrhea and more serious intestinal conditions such as colitis. Symptoms include Watery ... Loss of appetite Nausea Abdominal pain or tenderness C. difficile is more common in people who need ...

  4. Enumeration of Rectangles in a Tableau Shape

    Science.gov (United States)

    Mingus, Tabitha T. Y.; Grassl, Richard M.; Diaz, Ricardo; Andrew, Lane; Parker, Frieda

    2010-01-01

    This article analyzes the challenge of counting the number of rectangles of all sizes in the n-tableau and to provide a combinatorial reason for the answer. The authors present a solution on enumerating rectangles in the n-tableau using Grassl and Mingus results. The authors demonstrate their conjecture for the n-tableau and attempt to apply their…

  5. Clostridium XIV Meeting

    Energy Technology Data Exchange (ETDEWEB)

    Lynd, Lee

    2016-08-28

    The 14th biannual Clostridium meeting was held at Dartmouth College from August 28 through 31, 2016. As noted in the meeting program (http://clostridiumxiv.com/wp-content/uploads/2016/09/Clostridium_XIV_program.pdf). the meeting featured 119 registered attendees, 33 oral presentations, 5 of which were given by younger presenters, 40 posters, and 2 keynote presentations, with strong participation by female and international scientists.

  6. Perceptual grouping affects haptic enumeration over the fingers

    NARCIS (Netherlands)

    Overvliet, K.E.; Plaisier, M.A.

    2016-01-01

    Spatial arrangement is known to influence enumeration times in vision. In haptic enumeration, it has been shown that dividing the total number of items over the two hands can speed up enumeration. Here we investigated how spatial arrangement of items and non-items presented to the individual fingers

  7. Circulating Tumor Cells, Enumeration and Beyond

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Jian-Mei [Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, Manchester M20 4BX (United Kingdom); Krebs, Matthew [Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, Manchester M20 4BX (United Kingdom); Christie Hospital Foundation NHS Trust, Manchester M20 4BX (United Kingdom); Ward, Tim; Morris, Karen; Sloane, Robert [Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, Manchester M20 4BX (United Kingdom); Blackhall, Fiona [Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, Manchester M20 4BX (United Kingdom); School of Cancer and Enabling Sciences, University of Manchester, Manchester Cancer Research Centre, Manchester Academic Health Sciences Centre, Manchester M20 4BX (United Kingdom); Christie Hospital Foundation NHS Trust, Manchester M20 4BX (United Kingdom); Dive, Caroline, E-mail: cdive@picr.man.ac.uk [Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, Manchester M20 4BX (United Kingdom); School of Cancer and Enabling Sciences, University of Manchester, Manchester Cancer Research Centre, Manchester Academic Health Sciences Centre, Manchester M20 4BX (United Kingdom)

    2010-06-09

    The detection and enumeration of circulating tumor cells (CTCs) has shown significant clinical utility with respect to prognosis in breast, colorectal and prostate cancers. Emerging studies show that CTCs can provide pharmacodynamic information to aid therapy decision making. CTCs as a ‘virtual and real-time biopsy’ have clear potential to facilitate exploration of tumor biology, and in particular, the process of metastasis. The challenge of profiling CTC molecular characteristics and generating CTC signatures using current technologies is that they enrich rather than purify CTCs from whole blood; we face the problem of looking for the proverbial ‘needle in the haystack’. This review summarizes the current methods for CTC detection and enumeration, focuses on molecular characterization of CTCs, unveils some aspects of CTC heterogeneity, describes attempts to purify CTCs and scans the horizon for approaches leading to comprehensive dissection of CTC biology.

  8. Circulating Tumor Cells, Enumeration and Beyond

    International Nuclear Information System (INIS)

    Hou, Jian-Mei; Krebs, Matthew; Ward, Tim; Morris, Karen; Sloane, Robert; Blackhall, Fiona; Dive, Caroline

    2010-01-01

    The detection and enumeration of circulating tumor cells (CTCs) has shown significant clinical utility with respect to prognosis in breast, colorectal and prostate cancers. Emerging studies show that CTCs can provide pharmacodynamic information to aid therapy decision making. CTCs as a ‘virtual and real-time biopsy’ have clear potential to facilitate exploration of tumor biology, and in particular, the process of metastasis. The challenge of profiling CTC molecular characteristics and generating CTC signatures using current technologies is that they enrich rather than purify CTCs from whole blood; we face the problem of looking for the proverbial ‘needle in the haystack’. This review summarizes the current methods for CTC detection and enumeration, focuses on molecular characterization of CTCs, unveils some aspects of CTC heterogeneity, describes attempts to purify CTCs and scans the horizon for approaches leading to comprehensive dissection of CTC biology

  9. Circulating Tumor Cells, Enumeration and Beyond

    Directory of Open Access Journals (Sweden)

    Jian-Mei Hou

    2010-06-01

    Full Text Available The detection and enumeration of circulating tumor cells (CTCs has shown significant clinical utility with respect to prognosis in breast, colorectal and prostate cancers. Emerging studies show that CTCs can provide pharmacodynamic information to aid therapy decision making. CTCs as a ‘virtual and real-time biopsy’ have clear potential to facilitate exploration of tumor biology, and in particular, the process of metastasis. The challenge of profiling CTC molecular characteristics and generating CTC signatures using current technologies is that they enrich rather than purify CTCs from whole blood; we face the problem of looking for the proverbial ‘needle in the haystack’. This review summarizes the current methods for CTC detection and enumeration, focuses on molecular characterization of CTCs, unveils some aspects of CTC heterogeneity, describes attempts to purify CTCs and scans the horizon for approaches leading to comprehensive dissection of CTC biology.

  10. A state enumeration of the foil knot

    OpenAIRE

    Ramaharo, Franck; Rakotondrajao, Fanja

    2017-01-01

    We split the crossings of the foil knot and enumerate the resulting states with a generating polynomial. Unexpectedly, the number of such states which consist of two components are given by the lazy caterer's sequence. This sequence describes the maximum number of planar regions that is obtained with a given number of straight lines. We then establish a bijection between this partition of the plane and the concerned foil splits sequence.

  11. Enumeration of connected Catalan objects by type

    OpenAIRE

    Rhoades, Brendon

    2010-01-01

    Noncrossing set partitions, nonnesting set partitions, Dyck paths, and rooted plane trees are four classes of Catalan objects which carry a notion of type. There exists a product formula which enumerates these objects according to type. We define a notion of `connectivity' for these objects and prove an analogous product formula which counts connected objects by type. Our proof of this product formula is combinatorial and bijective. We extend this to a product formula which counts objects wit...

  12. Characterization of a Unique Class C Acid Phosphatase from Clostridium perfringens▿

    Science.gov (United States)

    Reilly, Thomas J.; Chance, Deborah L.; Calcutt, Michael J.; Tanner, John J.; Felts, Richard L.; Waller, Stephen C.; Henzl, Michael T.; Mawhinney, Thomas P.; Ganjam, Irene K.; Fales, William H.

    2009-01-01

    Clostridium perfringens is a gram-positive anaerobe and a pathogen of medical importance. The detection of acid phosphatase activity is a powerful diagnostic indicator of the presence of C. perfringens among anaerobic isolates; however, characterization of the enzyme has not previously been reported. Provided here are details of the characterization of a soluble recombinant form of this cell-associated enzyme. The denatured enzyme was ∼31 kDa and a homodimer in solution. It catalyzed the hydrolysis of several substrates, including para-nitrophenyl phosphate, 4-methylumbelliferyl phosphate, and 3′ and 5′ nucleoside monophosphates at pH 6. Calculated Kms ranged from 0.2 to 0.6 mM with maximum velocity ranging from 0.8 to 1.6 μmol of Pi/s/mg. Activity was enhanced in the presence of some divalent cations but diminished in the presence of others. Wild-type enzyme was detected in all clinical C. perfringens isolates tested and found to be cell associated. The described enzyme belongs to nonspecific acid phosphatase class C but is devoid of lipid modification commonly attributed to this class. PMID:19363079

  13. Taxonogenomic description of four new Clostridium species isolated from human gut: ‘Clostridium amazonitimonense’, ‘Clostridium merdae’, ‘Clostridium massilidielmoense’ and ‘Clostridium nigeriense’

    Directory of Open Access Journals (Sweden)

    M.T. Alou

    2018-01-01

    Full Text Available Culturomics investigates microbial diversity of the human microbiome by combining diversified culture conditions, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and 16S rRNA gene identification. The present study allowed identification of four putative new Clostridium sensu stricto species: ‘Clostridium amazonitimonense’ strain LF2T, ‘Clostridium massilidielmoense’ strain MT26T, ‘Clostridium nigeriense’ strain Marseille-P2414T and ‘Clostridium merdae’ strain Marseille-P2953T, which we describe using the concept of taxonogenomics. We describe the main characteristics of each bacterium and present their complete genome sequence and annotation. Keywords: ‘Clostridium amazonitimonense’, ‘Clostridium massilidielmoense’, ‘Clostridium merdae’, ‘Clostridium nigeriense’, culturomics, emerging bacteria, human microbiota, taxonogenomics

  14. In-vitro growth characteristics of commercial probiotic strains and their potential for inhibition of Clostridium difficile and Clostridium perfringens

    DEFF Research Database (Denmark)

    Schoster, A.; Permin, A.; Kokotovic, Branko

    2012-01-01

    . To study growth characteristics of 17 commercial probiotic strains (Lactobacilli n=16, Bifidobacteria n=1) MRS broth was adjusted to pH 2 or 4 or supplemented with 0.15% or 0.3% bile. Growth was measured at 0 and 24h and compared spectrophotometrically to control growth in standard MRS broth. Growth under...

  15. Clostridium difficile Infection

    Science.gov (United States)

    ... TeensRead MoreBMI Calculator Acute BronchitisHigh Blood PressureBursitis of the HipHigh CholesterolExercise-induced UrticariaMicroscopic HematuriaKidney CystsDe Quervain’s Tenosynovitis Home Diseases and Conditions Clostridium difficile (C. diff.) ...

  16. Enumeration of Enterobacter cloacae after chloramine exposure.

    OpenAIRE

    Watters, S K; Pyle, B H; LeChevallier, M W; McFeters, G A

    1989-01-01

    Growth of Enterobacter cloacae on various media was compared after disinfection. This was done to examine the effects of monochloramine and chlorine on the enumeration of coliforms. The media used were TLY (nonselective; 5.5% tryptic soy broth, 0.3% yeast extract, 1.0% lactose, and 1.5% Bacto-Agar), m-T7 (selective; developed to recover injured coliforms), m-Endo (selective; contains sodium sulfite), TLYS (TLY with sodium sulfite), and m-T7S (m-T7 with sodium sulfite). Sodium sulfite in any m...

  17. Dense module enumeration in biological networks

    Science.gov (United States)

    Tsuda, Koji; Georgii, Elisabeth

    2009-12-01

    Analysis of large networks is a central topic in various research fields including biology, sociology, and web mining. Detection of dense modules (a.k.a. clusters) is an important step to analyze the networks. Though numerous methods have been proposed to this aim, they often lack mathematical rigorousness. Namely, there is no guarantee that all dense modules are detected. Here, we present a novel reverse-search-based method for enumerating all dense modules. Furthermore, constraints from additional data sources such as gene expression profiles or customer profiles can be integrated, so that we can systematically detect dense modules with interesting profiles. We report successful applications in human protein interaction network analyses.

  18. Dense module enumeration in biological networks

    International Nuclear Information System (INIS)

    Tsuda, Koji; Georgii, Elisabeth

    2009-01-01

    Analysis of large networks is a central topic in various research fields including biology, sociology, and web mining. Detection of dense modules (a.k.a. clusters) is an important step to analyze the networks. Though numerous methods have been proposed to this aim, they often lack mathematical rigorousness. Namely, there is no guarantee that all dense modules are detected. Here, we present a novel reverse-search-based method for enumerating all dense modules. Furthermore, constraints from additional data sources such as gene expression profiles or customer profiles can be integrated, so that we can systematically detect dense modules with interesting profiles. We report successful applications in human protein interaction network analyses.

  19. Enumeration of small collections violates Weber's law.

    Science.gov (United States)

    Choo, H; Franconeri, S L

    2014-02-01

    In a phenomenon called subitizing, we can immediately generate exact counts of small collections (one to three objects), in contrast to larger collections, for which we must either create rough estimates or serially count. A parsimonious explanation for this advantage for small collections is that noisy representations of small collections are more tolerable, due to the larger relative differences between consecutive numbers (e.g., 2 vs. 3 is a 50 % increase, but 10 vs. 11 is only a 10 % increase). In contrast, the advantage could stem from the fact that small-collection enumeration is more precise, relying on a unique mechanism. Here, we present two experiments that conclusively showed that the enumeration of small collections is indeed "superprecise." Participants compared numerosity within either small or large visual collections in conditions in which the relative differences were controlled (e.g., performance for 2 vs. 3 was compared with performance for 20 vs. 30). Small-number comparison was still faster and more accurate, across both "more-fewer" judgments (Exp. 1), and "same-different" judgments (Exp. 2). We then reviewed the remaining potential mechanisms that might underlie this superprecision for small collections, including the greater diagnostic value of visual features that correlate with number and a limited capacity for visually individuating objects.

  20. Potential for growth of Clostridium perfringens from spores in scrapple during cooling

    Science.gov (United States)

    Scrapple is an ethnic food produced/consumed almost exclusively in the Middle Atlantic states of the U.S. It is typically made from ground pork trimmings, seasonings, cornmeal, and flour. This mixture is cooked and then shaped into loaves that are cooled and subsequently stored refrigerated until sl...

  1. Effect of individual or combined treatment of heat or radiation on clostridium perfringens spores

    Energy Technology Data Exchange (ETDEWEB)

    El-Zawahry, Y A; El-Fouly, M Z; Aziz, N H

    1986-01-01

    Separate treatments of high temperature had considerable effect on Cl.perfrigens spores suspended in saline solution especially at 90 and 100[sup 0]C, while 70 and 80[sup 0]C had only slight effect on the spores viabilty. The decimal reduction times (D[sub T]) were 33.7, 26, 4, 10.7 and 2.8 at 70, 80, 90 and 100[sup 0]C for NCTC 8798 strain and were 45.1, 27.1, 10.2 and 4.0 for the Egyptian strain at the same degrees of temperature respectively. Heat treatment pre-irradiation at 70 and 80[sup 0]C for 30 and 60 min decreased the viable spore numbers by about 0.5 to 3.0 log cycles, but the treatment had no effect on increasing the sensitivity of the rest spores to radiation. The decimal reduction dose (D[sub 10]-value) for the spores was almost the same as the control but there was a tendency to reduce the shoulder part in the radiation response curve especially when the spores were subjected to 80[sup 0]C for 60 min. On the other hand, irradiation pre-heat treatment with doses from 1-10 KGY was sufficient to decrease the spore numbers from 0.2 to 5.0 log cycles and had a sensitizing effect on subsequently heated spores especially those exposed to 90 and 100[sup 0]C. Meanwhile the rate of inactivation for spores exposed to 70 and 80[sup 0]C after irradiation increased only during the first ten minutes. Thereafter, the rate of inactivation was almost the same for the non-irradiated spores. The D[sub 10]-values for the spores irradiated with 10 KGY were 0.77 and 0.84 minutes for NCTC 8798 strain and Egyptian strain at 100[sup 0]C respectively and the spores were completely destroyed before 5 minutes.

  2. Lyophilized Carnobacterium divergens AS7 bacteriocin preparation improves performance of broiler chickens challenged with Clostridium perfringens

    DEFF Research Database (Denmark)

    Jozefiak, D; Sip, A; Rutkowski, A

    2012-01-01

    isolates. In total, 480 one-day-old male Ross 308 chicks were randomly assigned to 4 experimental groups (12 replicate pens of 10 birds per treatment). The diets were either nonsupplemented or supplemented with a lyophilized preparation of divercin AS7. On d 18, 19, and 20, half of the birds were...

  3. Identification of bilirubin reduction products formed by Clostridium perfringens isolated from human neonatal fecal flora

    Czech Academy of Sciences Publication Activity Database

    Vítek, L.; Majer, F.; Muchová, L.; Zelenka, J.; Jirásková, A.; Branny, Pavel; Malina, J.; Ubik, Karel

    2006-01-01

    Roč. 833, - (2006), s. 149-157 ISSN 1570-0232 R&D Projects: GA ČR GA310/02/1436 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z40550506 Keywords : bilirubin * bacteria l reduction * intestinal microflora Subject RIV: EE - Microbiology, Virology Impact factor: 2.647, year: 2006

  4. 9 CFR 113.111 - Clostridium Perfringens Type C Toxoid and Bacterin-Toxoid.

    Science.gov (United States)

    2010-01-01

    ... tested for purity, safety, and potency as prescribed in this section. Any serial found unsatisfactory by... provided in this paragraph. (1) When used in this test, the following words and terms shall mean: (i... dissolving 1 gram of peptone and 0.25 grams of sodium chloride in each 100 ml of distilled water; adjusting...

  5. 9 CFR 113.112 - Clostridium Perfringens Type D Toxoid and Bacterin-Toxoid.

    Science.gov (United States)

    2010-01-01

    ... tested for purity, safety, and potency as prescribed in this section. Any serial found unsatisfactory by... provided in this paragraph. (1) When used in this test, the following words and terms shall mean: (i... distilled water; adjusting the pH to 7.2; autoclaving at 250 °F for 25 minutes; and storing at 4 °C until...

  6. Enumeration of Enterobacter cloacae after chloramine exposure.

    Science.gov (United States)

    Watters, S K; Pyle, B H; LeChevallier, M W; McFeters, G A

    1989-01-01

    Growth of Enterobacter cloacae on various media was compared after disinfection. This was done to examine the effects of monochloramine and chlorine on the enumeration of coliforms. The media used were TLY (nonselective; 5.5% tryptic soy broth, 0.3% yeast extract, 1.0% lactose, and 1.5% Bacto-Agar), m-T7 (selective; developed to recover injured coliforms), m-Endo (selective; contains sodium sulfite), TLYS (TLY with sodium sulfite), and m-T7S (m-T7 with sodium sulfite). Sodium sulfite in any medium improved the recovery of chloramine-treated E. cloacae. However, sodium sulfite in TLYS and m-T7S did not significantly improve the detection of chlorine-treated E. cloacae, and m-Endo was the least effective medium for recovering chlorinated bacteria. Differences in recovery of chlorine- and chloramine-treated E. cloacae are consistent with mechanistic differences between the disinfectants. PMID:2619309

  7. Aboriginal fractions: enumerating identity in Taiwan.

    Science.gov (United States)

    Liu, Jennifer A

    2012-01-01

    Notions of identity in Taiwan are configured in relation to numbers. I examine the polyvalent capacities of enumerative technologies in both the production of ethnic identities and claims to political representation and justice. By critically historicizing the manner in which Aborigines in Taiwan have been, and continue to be, constructed as objects and subjects of scientific knowledge production through technologies of measuring, I examine the genetic claim made by some Taiwanese to be "fractionally" Aboriginal. Numbers and techniques of measuring are used ostensibly to know the Aborigines, but they are also used to construct a genetically unique Taiwanese identity and to incorporate the Aborigines within projects of democratic governance. Technologies of enumeration thus serve within multiple, and sometimes contradictory, projects of representation and knowledge production.

  8. Enumeration of petroleum hydrocarbon utilizing bacteria

    International Nuclear Information System (INIS)

    Mukherjee, S.; Barot, M.; Levine, A.D.

    1996-01-01

    In-situ biological treatment is one among a number of emerging technologies that may be applied to the remediation of contaminated soils and groundwater. In 1985, a surface spill of 1,500 gallons of dielectric transformer oil at the Sandia National Laboratories (HERMES II facility) resulted in contamination of soil up to depths of 160 feet. The extent of contamination and site characteristics favored the application of in-situ bioremediation as a potential remedial technology. The purpose of this research was to enumerate indigenous microbial populations capable of degrading petroleum hydrocarbons. Microbial enumeration and characterization methods suitably adapted for hydrocarbon utilizing bacteria were used as an indicator of the presence of viable microbial consortia in excavated oil samples with hydrocarbon (TPH) concentrations ranging from 300 to 26,850 ppm. Microbial activity was quantified by direct and streak plating soil samples on silica gel media. Effects of toxicity and temperature were studied using batch cultures of hydrocarbon utilizing bacteria (selectively isolated in an enrichment medium), at temperatures of 20 and 35 C. It was concluded from this study that it is possible to isolate native microorganisms from contaminated soils from depths of 60 to 160 feet, and with oil concentration ranging from 300 to 26,850 ppm. About 62% of the microorganisms isolated form the contaminated soil were capable of using contaminant oil as a substrate for growth and metabolism under aerobic conditions. Growth rates were observed to be 50% higher for the highest contaminant concentration at 20 C. Resistance to toxicity to contaminant oil was also observed to be greater at 20 C than at 35 C

  9. Lactose-Inducible System for Metabolic Engineering of Clostridium ljungdahlii

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, A; Leang, C; Ueki, T; Nevin, KP; Lovley, DR

    2014-03-25

    The development of tools for genetic manipulation of Clostridium ljungdahlii has increased its attractiveness as a chassis for autotrophic production of organic commodities and biofuels from syngas and microbial electrosynthesis and established it as a model organism for the study of the basic physiology of acetogenesis. In an attempt to expand the genetic toolbox for C. ljungdahlii, the possibility of adapting a lactose-inducible system for gene expression, previously reported for Clostridium perfringens, was investigated. The plasmid pAH2, originally developed for C. perfringens with a gusA reporter gene, functioned as an effective lactose-inducible system in C. ljungdahlii. Lactose induction of C. ljungdahlii containing pB1, in which the gene for the aldehyde/alcohol dehydrogenase AdhE1 was downstream of the lactose-inducible promoter, increased expression of adhE1 30-fold over the wild-type level, increasing ethanol production 1.5-fold, with a corresponding decrease in acetate production. Lactose-inducible expression of adhE1 in a strain in which adhE1 and the adhE1 homolog adhE2 had been deleted from the chromosome restored ethanol production to levels comparable to those in the wild-type strain. Inducing expression of adhE2 similarly failed to restore ethanol production, suggesting that adhE1 is the homolog responsible for ethanol production. Lactose-inducible expression of the four heterologous genes necessary to convert acetyl coenzyme A (acetyl-CoA) to acetone diverted ca. 60% of carbon flow to acetone production during growth on fructose, and 25% of carbon flow went to acetone when carbon monoxide was the electron donor. These studies demonstrate that the lactose-inducible system described here will be useful for redirecting carbon and electron flow for the biosynthesis of products more valuable than acetate. Furthermore, this tool should aid in optimizing microbial electrosynthesis and for basic studies on the physiology of acetogenesis.

  10. Lactose-Inducible System for Metabolic Engineering of Clostridium ljungdahlii

    Science.gov (United States)

    Ueki, Toshiyuki; Nevin, Kelly P.; Lovley, Derek R.

    2014-01-01

    The development of tools for genetic manipulation of Clostridium ljungdahlii has increased its attractiveness as a chassis for autotrophic production of organic commodities and biofuels from syngas and microbial electrosynthesis and established it as a model organism for the study of the basic physiology of acetogenesis. In an attempt to expand the genetic toolbox for C. ljungdahlii, the possibility of adapting a lactose-inducible system for gene expression, previously reported for Clostridium perfringens, was investigated. The plasmid pAH2, originally developed for C. perfringens with a gusA reporter gene, functioned as an effective lactose-inducible system in C. ljungdahlii. Lactose induction of C. ljungdahlii containing pB1, in which the gene for the aldehyde/alcohol dehydrogenase AdhE1 was downstream of the lactose-inducible promoter, increased expression of adhE1 30-fold over the wild-type level, increasing ethanol production 1.5-fold, with a corresponding decrease in acetate production. Lactose-inducible expression of adhE1 in a strain in which adhE1 and the adhE1 homolog adhE2 had been deleted from the chromosome restored ethanol production to levels comparable to those in the wild-type strain. Inducing expression of adhE2 similarly failed to restore ethanol production, suggesting that adhE1 is the homolog responsible for ethanol production. Lactose-inducible expression of the four heterologous genes necessary to convert acetyl coenzyme A (acetyl-CoA) to acetone diverted ca. 60% of carbon flow to acetone production during growth on fructose, and 25% of carbon flow went to acetone when carbon monoxide was the electron donor. These studies demonstrate that the lactose-inducible system described here will be useful for redirecting carbon and electron flow for the biosynthesis of products more valuable than acetate. Furthermore, this tool should aid in optimizing microbial electrosynthesis and for basic studies on the physiology of acetogenesis. PMID:24509933

  11. Cloning and sequence analysis of hyaluronoglucosaminidase (nagH gene of Clostridium chauvoei

    Directory of Open Access Journals (Sweden)

    Saroj K. Dangi

    2017-09-01

    Full Text Available Aim: Blackleg disease is caused by Clostridium chauvoei in ruminants. Although virulence factors such as C. chauvoei toxin A, sialidase, and flagellin are well characterized, hyaluronidases of C. chauvoei are not characterized. The present study was aimed at cloning and sequence analysis of hyaluronoglucosaminidase (nagH gene of C. chauvoei. Materials and Methods: C. chauvoei strain ATCC 10092 was grown in ATCC 2107 media and confirmed by polymerase chain reaction (PCR using the primers specific for 16-23S rDNA spacer region. nagH gene of C. chauvoei was amplified and cloned into pRham-SUMO vector and transformed into Escherichia cloni 10G cells. The construct was then transformed into E. cloni cells. Colony PCR was carried out to screen the colonies followed by sequencing of nagH gene in the construct. Results: PCR amplification yielded nagH gene of 1143 bp product, which was cloned in prokaryotic expression system. Colony PCR, as well as sequencing of nagH gene, confirmed the presence of insert. Sequence was then subjected to BLAST analysis of NCBI, which confirmed that the sequence was indeed of nagH gene of C. chauvoei. Phylogenetic analysis of the sequence showed that it is closely related to Clostridium perfringens and Clostridium paraputrificum. Conclusion: The gene for virulence factor nagH was cloned into a prokaryotic expression vector and confirmed by sequencing.

  12. Enumeration, isolation and identification of bacteria and fungi from ...

    African Journals Online (AJOL)

    Enumeration, isolation and identification of bacteria and fungi from soil contaminated with petroleum products ... dropping can be useful in the bioremediation of soil contaminated with petroleum products and possibly other oil polluted sites.

  13. Top-k Based Adaptive Enumeration in Constraint Programming

    Directory of Open Access Journals (Sweden)

    Ricardo Soto

    2015-01-01

    order for variables and values is employed along the search. In this paper, we present a new and more lightweight approach for performing adaptive enumeration. We incorporate a powerful classification technique named Top-k in order to adaptively select strategies along the resolution. We report results on a set of well-known benchmarks where the proposed approach noticeably competes with classical and modern adaptive enumeration methods for constraint satisfaction.

  14. Diagnosis of Clostridium difficile

    DEFF Research Database (Denmark)

    Jensen, M B F; Olsen, K E P; Nielsen, X C

    2015-01-01

    The diagnosis of Clostridium difficile infection (CDI) requires the detection of toxigenic C. difficile or its toxins and a clinical assessment. We evaluated the performance of four nucleic acid amplification tests (NAATs) detecting toxigenic C. difficile directly from faeces compared to routine...... ribotyping and toxinotyping (TT) were performed on culture-positive samples. In parallel, the samples were analysed by four NAATs; two targeting tcdA or tcdB (illumigene® C. difficile and PCRFast® C. difficile A/B) and two multi-target real-time (RT) PCR assays also targeting cdt and tcdC alleles...... characteristic of epidemic and potentially more virulent PCR ribotypes 027, 066 and 078 (GeneXpert® C. difficile/Epi and an 'in-house RT PCR' two-step algorithm). The multi-target assays were significantly more sensitive compared to routine toxigenic culture (p 

  15. Special Concerns for Seniors: Clostridium difficile

    Science.gov (United States)

    ... and Drugs" Home | Contact Us Special Concerns for Seniors Clostridium difficile - an introduction Clostridium difficile (“C. diff”) ... see APUA’s contribution to CDC’s Vital Signs campaign . Seniors are especially at risk People over the age ...

  16. Clostridium subterminale septicemia in an immunocompetent patient

    OpenAIRE

    Daganou Maria; Kyriakoudi Ann; Moraitou Helen; Pontikis Konstantinos; Avgeropoulou Stavrina; Tripolitsioti Paraskevi; Koutsoukou Antonia

    2016-01-01

    Clostridium subterminale is a Clostridium species that has been rarely isolated in the blood of immunocompromised patients. We report a case of C. subterminale septicemia in an immunocompetent patient who presented with acute mediastinitis following spontaneous esophageal rupture.

  17. Clostridium subterminale septicemia in an immunocompetent patient.

    Science.gov (United States)

    Daganou, Maria; Kyriakoudi, Ann; Moraitou, Helen; Pontikis, Konstantinos; Avgeropoulou, Stavrina; Tripolitsioti, Paraskevi; Koutsoukou, Antonia

    2016-01-01

    Clostridium subterminale is a Clostridium species that has been rarely isolated in the blood of immunocompromised patients. We report a case of C. subterminale septicemia in an immunocompetent patient who presented with acute mediastinitis following spontaneous esophageal rupture.

  18. Proposal to restrict the genus Clostridium Prazmowski to Clostridium butyricum and related species.

    Science.gov (United States)

    Lawson, Paul A; Rainey, Fred A

    2016-02-01

    The genus Clostridium as presently constituted is phylogenetically and phenotypically incoherent. Data from polyphasic taxonomic studies indicate that the genus comprises a collection of very heterogeneous species. Numerous phylogenetic studies, principally based on sequencing of the 16S rRNA gene, indicate that the genus Clostridium should be restricted to Clostridium cluster I as Clostridium sensu stricto . Despite these findings, authors continue to add novel species to the genus Clostridium that do not fall within the radiation of cluster I and the type species Clostridium butyricum , thus perpetuating the confusion associated with the taxonomy of this group. Here, we formally propose that members of the genus Clostridium Prazmowski be restricted to the type species C. butyricum and cluster I species. Eubacterium moniliforme , Eubacterium tarantellae , Sarcina maxima and Sarcina ventriculi should be transferred to the genus Clostridium as Clostridium moniliforme comb. nov., Clostridium tarantellae comb. nov., Clostridium maximum comb. nov. and Clostridium ventriculi comb. nov. A novel genus, Hathewaya gen. nov., is proposed for the species Clostridium histolyticum , Clostridium limosum and Clostridium proteolyticum as Hathewaya histolytica gen. nov. comb. nov., Hathewaya limosa comb. nov. and Hathewaya proteolytica comb. nov. The type species of the genus Hathewaya is Hathewaya histolytica.

  19. The Binary Toxin CDT of Clostridium difficile as a Tool for Intracellular Delivery of Bacterial Glucosyltransferase Domains

    Directory of Open Access Journals (Sweden)

    Lara-Antonia Beer

    2018-06-01

    Full Text Available Binary toxins are produced by several pathogenic bacteria. Examples are the C2 toxin from Clostridium botulinum, the iota toxin from Clostridium perfringens, and the CDT from Clostridium difficile. All these binary toxins have ADP-ribosyltransferases (ADPRT as their enzymatically active component that modify monomeric actin in their target cells. The binary C2 toxin was intensively described as a tool for intracellular delivery of allogenic ADPRTs. Here, we firstly describe the binary toxin CDT from C. difficile as an effective tool for heterologous intracellular delivery. Even 60 kDa glucosyltransferase domains of large clostridial glucosyltransferases can be delivered into cells. The glucosyltransferase domains of five tested large clostridial glucosyltransferases were successfully introduced into cells as chimeric fusions to the CDTa adapter domain (CDTaN. Cell uptake was demonstrated by the analysis of cell morphology, cytoskeleton staining, and intracellular substrate glucosylation. The fusion toxins were functional only when the adapter domain of CDTa was N-terminally located, according to its native orientation. Thus, like other binary toxins, the CDTaN/b system can be used for standardized delivery systems not only for bacterial ADPRTs but also for a variety of bacterial glucosyltransferase domains.

  20. Mupirocin-mucin agar for selective enumeration of Bifidobacterium bifidum

    Czech Academy of Sciences Publication Activity Database

    Pechar, R.; Rada, V.; Parafati, L.; Musilová, S.; Bunešová, V.; Vlková, E.; Killer, Jiří; Mrázek, Jakub; Kmeť, V.; Svejštil, R.

    2014-01-01

    Roč. 191, č. 1 (2014), s. 32-35 ISSN 0168-1605 R&D Projects: GA ČR GA13-08803S Institutional support: RVO:67985904 Keywords : probiotics * Bifidobacterium bifidum * selective enumeration Subject RIV: EE - Microbiology, Virology Impact factor: 3.082, year: 2014

  1. Enumeration and estimation of insect attack fruits of some cultivars ...

    African Journals Online (AJOL)

    In this study, five cultivars of Punica granatum identified (two of which are endemic, while the other three are new) were grown in certain farms at Al-Taif, Saudi Arabia. Enumeration to the insects attack its' fruits illustrated that, there are three insects, namely, Virchola livia, Ectomyelois ceratonia and Pseudococcus maitimus ...

  2. Immunophenotypic enumeration of CD4 + T-lymphocyte values in ...

    African Journals Online (AJOL)

    Background: The enumeration of CD4+ T-lymphocytes in Human Immunodeficiency Virus (HIV)-infected individuals is an essential tool for staging HIV disease, to make decisions for initiation of anti-retroviral therapy (ART), for monitoring response to ART and to initiate chemoprophylaxis against opportunistic infections.

  3. A combinatorial enumeration problem of RNA secondary structures

    African Journals Online (AJOL)

    use

    2011-12-21

    Dec 21, 2011 ... interesting combinatorial questions (Chen et al., 2005;. Liu, 2006; Schmitt and Waterman 1994; Stein and. Waterman 1978). The research on the enumeration of. RNA secondary structures becomes one of the hot topics in Computational Molecular Biology. An RNA molecule is described by its sequences of.

  4. Clostridium difficile Infection in Outpatients

    Centers for Disease Control (CDC) Podcasts

    2011-11-07

    Dr. Jon Mark Hirshon, Associate Professor of Emergency Medicine at the University of Maryland School of Medicine, discusses Clostridium difficile infection in outpatients.  Created: 11/7/2011 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 11/21/2011.

  5. Clostridium difficile in Retail Meats

    Centers for Disease Control (CDC) Podcasts

    Clostridium difficile is a common cause of diarrhea in healthcare settings but little is known about what causes cases in the community. In this podcast, CDC's Dr. L. Clifford McDonald discusses two papers in the May 2009 edition of Emerging Infectious Diseases that explore whether the organism could be found in meat samples purchased in grocery stores in Arizona and Canada.

  6. Viability of Clostridium sporogenes spores after CaO hygienization of meat waste

    Directory of Open Access Journals (Sweden)

    Justyna Bauza-Kaszewska

    2014-09-01

    Full Text Available The occurrence of the pathogenic species [i]C. perfringens[/i] and [i]C. botulinum spores[/i] in animal by-products poses a potential epidemiological hazard. Strong entero- and neurotoxins produced by these bacteria adversely affect human health. To inactivate pathogens present in animal by-products, waste must be subjected to various methods of sanitization. The aim of the presented study was to estimate the effect of different doses of CaO on the viability of spores [i] Clostridium sporogenes[/i] in meat wastes category 3. During the research, two doses of burnt lime were added to the poultry mince meat and meat mixed with swine blood contaminated with [i]Clostridium sporogenes[/i] spore suspension. Half of the samples collected for microbiological analyses were buffered to achieve the pH level ~7, the other were examined without pH neutralization. To estimate the spore number, 10-fold dilution series in peptone water was prepared and heat-treated at 80 °C for 10 min. After cooling-down, one milliliter of each dilution was pour-plated onto DRCM medium solidified with agar. Statistical analysis were performed using the Statistica software. Application of 70% CaO caused complete inactivation of [i]Clostridium spores[/i] in meat wastes after 48 hours. The highest temperature achieved during the experiment was 67 °C. Rapid alkalization of the biomass resulted in increasing pH to values exceeding 12. The effect of liming was not dependent on the meat wastes composition nor CaO dose. The experiment proved the efficiency of liming as a method of animal by-products sanitization. Application of the obtained results may help reduce the epidemiological risk and ensure safety to people handling meat wastes at each stage of their processing and utilization.

  7. Enumeration of self-avoiding walks on the square lattice

    International Nuclear Information System (INIS)

    Jensen, Iwan

    2004-01-01

    We describe a new algorithm for the enumeration of self-avoiding walks on the square lattice. Using up to 128 processors on a HP Alpha server cluster we have enumerated the number of self-avoiding walks on the square lattice to length 71. Series for the metric properties of mean-square end-to-end distance, mean-square radius of gyration and mean-square distance of monomers from the end points have been derived to length 59. An analysis of the resulting series yields accurate estimates of the critical exponents γ and ν confirming predictions of their exact values. Likewise we obtain accurate amplitude estimates yielding precise values for certain universal amplitude combinations. Finally we report on an analysis giving compelling evidence that the leading non-analytic correction-to-scaling exponent Δ 1 = 3/2

  8. Probiotic bacteria: selective enumeration and survival in dairy foods.

    Science.gov (United States)

    Shah, N P

    2000-04-01

    A number of health benefits have been claimed for probiotic bacteria such as Lactobacillus acidophilus, Bifidobacterium spp., and Lactobacillus casei. Because of the potential health benefits, these organisms are increasingly incorporated into dairy foods. However, studies have shown low viability of probiotics in market preparations. In order to assess viability of probiotic bacteria, it is important to have a working method for selective enumeration of these probiotic bacteria. Viability of probiotic bacteria is important in order to provide health benefits. Viability of probiotic bacteria can be improved by appropriate selection of acid and bile resistant strains, use of oxygen impermeable containers, two-step fermentation, micro-encapsulation, stress adaptation, incorporation of micronutrients such as peptides and amino acids and by sonication of yogurt bacteria. This review will cover selective enumeration and survival of probiotic bacteria in dairy foods.

  9. Enumeration of minimal stoichiometric precursor sets in metabolic networks.

    Science.gov (United States)

    Andrade, Ricardo; Wannagat, Martin; Klein, Cecilia C; Acuña, Vicente; Marchetti-Spaccamela, Alberto; Milreu, Paulo V; Stougie, Leen; Sagot, Marie-France

    2016-01-01

    What an organism needs at least from its environment to produce a set of metabolites, e.g. target(s) of interest and/or biomass, has been called a minimal precursor set. Early approaches to enumerate all minimal precursor sets took into account only the topology of the metabolic network (topological precursor sets). Due to cycles and the stoichiometric values of the reactions, it is often not possible to produce the target(s) from a topological precursor set in the sense that there is no feasible flux. Although considering the stoichiometry makes the problem harder, it enables to obtain biologically reasonable precursor sets that we call stoichiometric. Recently a method to enumerate all minimal stoichiometric precursor sets was proposed in the literature. The relationship between topological and stoichiometric precursor sets had however not yet been studied. Such relationship between topological and stoichiometric precursor sets is highlighted. We also present two algorithms that enumerate all minimal stoichiometric precursor sets. The first one is of theoretical interest only and is based on the above mentioned relationship. The second approach solves a series of mixed integer linear programming problems. We compared the computed minimal precursor sets to experimentally obtained growth media of several Escherichia coli strains using genome-scale metabolic networks. The results show that the second approach efficiently enumerates minimal precursor sets taking stoichiometry into account, and allows for broad in silico studies of strains or species interactions that may help to understand e.g. pathotype and niche-specific metabolic capabilities. sasita is written in Java, uses cplex as LP solver and can be downloaded together with all networks and input files used in this paper at http://www.sasita.gforge.inria.fr.

  10. Planar articulated mechanism design by graph theoretical enumeration

    DEFF Research Database (Denmark)

    Kawamoto, A; Bendsøe, Martin P.; Sigmund, Ole

    2004-01-01

    This paper deals with design of articulated mechanisms using a truss-based ground-structure representation. By applying a graph theoretical enumeration approach we can perform an exhaustive analysis of all possible topologies for a test example for which we seek a symmetric mechanism. This guaran....... This guarantees that one can identify the global optimum solution. The result underlines the importance of mechanism topology and gives insight into the issues specific to articulated mechanism designs compared to compliant mechanism designs....

  11. Detergent-Resistant Membrane Microdomains Facilitate Ib Oligomer Formation and Biological Activity of Clostridium perfringens Iota-Toxin

    National Research Council Canada - National Science Library

    Hale, Martha

    2004-01-01

    ...) were extracted with cold Triton X-100. Western blotting revealed that Ib oligomers localized in DRMs extracted from Vero, but not MRC-5, cells while monomeric Ib was detected in the detergent-soluble fractions of both cell types...

  12. Predicting outgrowth and inactivation of Clostridium perfringens in meat products during low temperature long time heat treatment

    DEFF Research Database (Denmark)

    Duan, Zhi; Holst Hansen, Terese; Hansen, Tina Beck

    OBJECTIVE Sous-vide cooking and molecular gastronomy has started a wave of experimenting with Low Temperature Long Time (LTLT) heat treatments. Heat treatments, at temperatures as low as 50°C, have been suggested by celebrity chefs. LTLT treatments often take hours to reach to the final core...

  13. IN-VITRO GROWTH CHARACTERISTICS OF COMMERCIAL PROBIOTIC STRAINS AND THEIR POTENTIAL FOR INHIBITION OF CLOSTRIDIUM DIFFICILE AND CLOSTRDIDUM PERFRINGENS

    DEFF Research Database (Denmark)

    Schoster, Angelika; Kokotovic, Branko; Permin, Anders

    . To study growth characteristics of 17 commercial probiotic strains (Lactobacilli n=16, Bifidobacteria n=1) MRS broth was adjusted to pH 2 or 4 or supplemented with 0.15% or 0.3% bile. Growth was measured at 0 and 24h and compared spectrophotometrically to control growth in standard MRS broth. Growth under...

  14. Clostridium subterminale septicemia in an immunocompetent patient

    Directory of Open Access Journals (Sweden)

    Daganou Maria

    2016-01-01

    Full Text Available Clostridium subterminale is a Clostridium species that has been rarely isolated in the blood of immunocompromised patients. We report a case of C. subterminale septicemia in an immunocompetent patient who presented with acute mediastinitis following spontaneous esophageal rupture.

  15. Assessing Methanobrevibacter smithii and Clostridium difficile as not conventional faecal indicators in effluents of a wastewater treatment plant integrated with sludge anaerobic digestion.

    Science.gov (United States)

    Romanazzi, Valeria; Bonetta, Silvia; Fornasero, Stefania; De Ceglia, Margherita; Gilli, Giorgio; Traversi, Deborah

    2016-12-15

    Wastewater treatment plants (WWTP) are an important source of surface water contamination by enteric pathogens, affecting the role of environmental water as a microbial reservoir. We describe the release to the environment of certain anaerobes of human and environmental concern. The work was focused on emerging microbial targets. They are tracing, by RT-qPCR, on WWTP effluents, both liquid and solid, when an anaerobic digestion step is included. The focus is placed on Clostridium spp. with the specific quantification of Clostridium perfringens, as typical bioindicator, and Clostridium difficile, as emerging pathogen not only confined into nosocomial infection. Moreover methanogens were quantified for their involvement in the anaerobic digestion, and in particular on Methanobrevibacter smithii as major methanogenic component of the human gut microbiome and as not conventional faecal indicator. In the water samples, a reduction, statistically significant, in all microbial targets was observed (p effluents, particularly bio-solids, to reduce the potential release of pathogens into the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Simple method for correct enumeration of Staphylococcus aureus

    DEFF Research Database (Denmark)

    Haaber, J.; Cohn, M. T.; Petersen, A.

    2016-01-01

    culture. When grown in such liquid cultures, the human pathogen Staphylococcus aureus is characterized by its aggregation of single cells into clusters of variable size. Here, we show that aggregation during growth in the laboratory standard medium tryptic soy broth (TSB) is common among clinical...... and laboratory S. aureus isolates and that aggregation may introduce significant bias when applying standard enumeration methods on S. aureus growing in laboratory batch cultures. We provide a simple and efficient sonication procedure, which can be applied prior to optical density measurements to give...

  17. Clostridium difficile in Retail Meats

    Centers for Disease Control (CDC) Podcasts

    2009-04-16

    Clostridium difficile is a common cause of diarrhea in healthcare settings but little is known about what causes cases in the community. In this podcast, CDC's Dr. L. Clifford McDonald discusses two papers in the May 2009 edition of Emerging Infectious Diseases that explore whether the organism could be found in meat samples purchased in grocery stores in Arizona and Canada.  Created: 4/16/2009 by Emerging Infectious Diseases.   Date Released: 4/16/2009.

  18. MacWilliams Identity for M-Spotty Weight Enumerator

    Science.gov (United States)

    Suzuki, Kazuyoshi; Fujiwara, Eiji

    M-spotty byte error control codes are very effective for correcting/detecting errors in semiconductor memory systems that employ recent high-density RAM chips with wide I/O data (e.g., 8, 16, or 32bits). In this case, the width of the I/O data is one byte. A spotty byte error is defined as random t-bit errors within a byte of length b bits, where 1 le t ≤ b. Then, an error is called an m-spotty byte error if at least one spotty byte error is present in a byte. M-spotty byte error control codes are characterized by the m-spotty distance, which includes the Hamming distance as a special case for t =1 or t = b. The MacWilliams identity provides the relationship between the weight distribution of a code and that of its dual code. The present paper presents the MacWilliams identity for the m-spotty weight enumerator of m-spotty byte error control codes. In addition, the present paper clarifies that the indicated identity includes the MacWilliams identity for the Hamming weight enumerator as a special case.

  19. Enumerating all maximal frequent subtrees in collections of phylogenetic trees.

    Science.gov (United States)

    Deepak, Akshay; Fernández-Baca, David

    2014-01-01

    A common problem in phylogenetic analysis is to identify frequent patterns in a collection of phylogenetic trees. The goal is, roughly, to find a subset of the species (taxa) on which all or some significant subset of the trees agree. One popular method to do so is through maximum agreement subtrees (MASTs). MASTs are also used, among other things, as a metric for comparing phylogenetic trees, computing congruence indices and to identify horizontal gene transfer events. We give algorithms and experimental results for two approaches to identify common patterns in a collection of phylogenetic trees, one based on agreement subtrees, called maximal agreement subtrees, the other on frequent subtrees, called maximal frequent subtrees. These approaches can return subtrees on larger sets of taxa than MASTs, and can reveal new common phylogenetic relationships not present in either MASTs or the majority rule tree (a popular consensus method). Our current implementation is available on the web at https://code.google.com/p/mfst-miner/. Our computational results confirm that maximal agreement subtrees and all maximal frequent subtrees can reveal a more complete phylogenetic picture of the common patterns in collections of phylogenetic trees than maximum agreement subtrees; they are also often more resolved than the majority rule tree. Further, our experiments show that enumerating maximal frequent subtrees is considerably more practical than enumerating ordinary (not necessarily maximal) frequent subtrees.

  20. Enumerating all maximal frequent subtrees in collections of phylogenetic trees

    Science.gov (United States)

    2014-01-01

    Background A common problem in phylogenetic analysis is to identify frequent patterns in a collection of phylogenetic trees. The goal is, roughly, to find a subset of the species (taxa) on which all or some significant subset of the trees agree. One popular method to do so is through maximum agreement subtrees (MASTs). MASTs are also used, among other things, as a metric for comparing phylogenetic trees, computing congruence indices and to identify horizontal gene transfer events. Results We give algorithms and experimental results for two approaches to identify common patterns in a collection of phylogenetic trees, one based on agreement subtrees, called maximal agreement subtrees, the other on frequent subtrees, called maximal frequent subtrees. These approaches can return subtrees on larger sets of taxa than MASTs, and can reveal new common phylogenetic relationships not present in either MASTs or the majority rule tree (a popular consensus method). Our current implementation is available on the web at https://code.google.com/p/mfst-miner/. Conclusions Our computational results confirm that maximal agreement subtrees and all maximal frequent subtrees can reveal a more complete phylogenetic picture of the common patterns in collections of phylogenetic trees than maximum agreement subtrees; they are also often more resolved than the majority rule tree. Further, our experiments show that enumerating maximal frequent subtrees is considerably more practical than enumerating ordinary (not necessarily maximal) frequent subtrees. PMID:25061474

  1. Automated Mobile System for Accurate Outdoor Tree Crop Enumeration Using an Uncalibrated Camera

    OpenAIRE

    Thuy Tuong Nguyen; David C. Slaughter; Bradley D. Hanson; Andrew Barber; Amy Freitas; Daniel Robles; Erin Whelan

    2015-01-01

    This paper demonstrates an automated computer vision system for outdoor tree crop enumeration in a seedling nursery. The complete system incorporates both hardware components (including an embedded microcontroller, an odometry encoder, and an uncalibrated digital color camera) and software algorithms (including microcontroller algorithms and the proposed algorithm for tree crop enumeration) required to obtain robust performance in a natural outdoor environment. The enumeration system uses a t...

  2. The association of color memory and the enumeration of multiple spatially overlapping sets.

    Science.gov (United States)

    Poltoratski, Sonia; Xu, Yaoda

    2013-07-09

    Using dot displays, Halberda, Sires, and Feigenson (2006) showed that observers could simultaneously encode the numerosity of two spatially overlapping sets and the superset of all items at a glance. With the brief display and the masking used in Halberda et al., the task required observers to encode the colors of each set in order to select and enumerate all the dots in that set. As such, the observed capacity limit for set enumeration could reflect a limit in visual short-term memory (VSTM) capacity for the set color rather than a limit in set enumeration per se. Here, we largely replicated Halberda et al. and found successful enumeration of approximately two sets (the superset was not probed). We also found that only about two and a half colors could be remembered from the colored dot displays whether or not the enumeration task was performed concurrently with the color VSTM task. Because observers must remember the color of a set prior to enumerating it, the under three-item VSTM capacity for color necessarily dictates that set enumeration capacity in this paradigm could not exceed two sets. Thus, the ability to enumerate multiple spatially overlapping sets is likely limited by VSTM capacity to retain the discriminating feature of these sets. This relationship suggests that the capacity for set enumeration cannot be considered independently from the capacity for the set's defining features.

  3. Nieuwe mogelijkheden bij Clostridium difficile-infecties

    NARCIS (Netherlands)

    van Nood, Els; Keller, Josbert J.; Kuijper, Ed J.; Speelman, Peter

    2013-01-01

    Currently available broad spectrum antibiotics are not sufficiently effective against recurrent Clostridium difficile infections (CDI). Donor faecal microbiota transplantation is a very effective treatment for second and recurrent infection but is time-consuming and requires careful screening of

  4. Prevalence and Characterization of a Binary Toxin (Actin-Specific ADP-Ribosyltransferase) from Clostridium difficile

    Science.gov (United States)

    Gonçalves, Carina; Decré, Dominique; Barbut, Frédéric; Burghoffer, Béatrice; Petit, Jean-Claude

    2004-01-01

    In addition to the two large clostridial cytotoxins (TcdA and TcdB), some strains of Clostridium difficile also produce an actin-specific ADP-ribosyltransferase, called binary toxin CDT. We used a PCR method and Southern blotting for the detection of genes encoding the enzymatic (CDTa) and binding (CDTb) components of the binary toxin in 369 strains isolated from patients with suspected C. difficile-associated diarrhea or colitis. Twenty-two strains (a prevalence of 6%) harbored both genes. When binary toxin production was assessed by Western blotting, 19 of the 22 strains reacted with antisera against the iota toxin of C. perfringens (anti-Ia and anti-Ib). Additionally, binary toxin activity, detected by the ADP-ribosyltransferase assay, was present in only 17 of the 22 strains. Subsequently, all 22 binary toxin-positive strains were tested for the production of toxins TcdA and TcdB, toxinotyped, and characterized by serogrouping, PCR ribotyping, arbitrarily primed PCR, and pulsed-field gel electrophoresis. All binary toxin-positive strains also produced TcdB and/or TcdA. However, they had significant changes in the tcdA and tcdB genes and belonged to variant toxinotypes III, IV, V, VII, IX, and XIII. We could differentiate 16 profiles by using typing methods, indicating that most of the binary toxin-positive strains were unrelated. PMID:15131151

  5. Algebraic computability and enumeration models recursion theory and descriptive complexity

    CERN Document Server

    Nourani, Cyrus F

    2016-01-01

    This book, Algebraic Computability and Enumeration Models: Recursion Theory and Descriptive Complexity, presents new techniques with functorial models to address important areas on pure mathematics and computability theory from the algebraic viewpoint. The reader is first introduced to categories and functorial models, with Kleene algebra examples for languages. Functorial models for Peano arithmetic are described toward important computational complexity areas on a Hilbert program, leading to computability with initial models. Infinite language categories are also introduced to explain descriptive complexity with recursive computability with admissible sets and urelements. Algebraic and categorical realizability is staged on several levels, addressing new computability questions with omitting types realizably. Further applications to computing with ultrafilters on sets and Turing degree computability are examined. Functorial models computability is presented with algebraic trees realizing intuitionistic type...

  6. Enumeration of microbial populations in radioactive environments by epifluorescence microscopy

    International Nuclear Information System (INIS)

    Pansoy-Hjelvik, M.E.; Strietelmeier, B.A.; Paffett, M.T.

    1997-01-01

    Epifluorescence microscopy was utilized to enumerate halophilic bacterial populations in two studies involving inoculated, actual waste/brine mixtures and pure brine solutions. The studies include an initial set of experiments designed to elucidate potential transformations of actinide-containing wastes under salt-repository conditions, including microbially mediated changes. The first study included periodic enumeration of bacterial populations of a mixed inoculum initially added to a collection of test containers. The contents of the test containers are the different types of actual radioactive waste that could potentially be stored in nuclear waste repositories in a salt environment. The transuranic waste was generated from materials used in actinide laboratory research. The results show that cell numbers decreased with time. Sorption of the bacteria to solid surfaces in the test system is discussed as a possible mechanism for the decrease in cell numbers. The second study was designed to determine radiological and/or chemical effects of 239 Pu, 243 Am, 237 Np, 232 Th and 238 U on the growth of pure and mixed anaerobic, denitrifying bacterial cultures in brine media. Pu, Am, and Np isotopes at concentrations of ≤1x10 -6 M , ≤5x10 -6 M and ≤5x10 -4 M respectively, and Th and U isotopes ≤4x10 -3 M were tested in these media. The results indicate that high concentrations of certain actinides affected both the bacterial growth rate and morphology. However, relatively minor effects from Am were observed at all tested concentrations with the pure culture

  7. Comparative pathogenomics of Clostridium tetani.

    Directory of Open Access Journals (Sweden)

    Jonathan E Cohen

    Full Text Available Clostridium tetani and Clostridium botulinum produce two of the most potent neurotoxins known, tetanus neurotoxin and botulinum neurotoxin, respectively. Extensive biochemical and genetic investigation has been devoted to identifying and characterizing various C. botulinum strains. Less effort has been focused on studying C. tetani likely because recently sequenced strains of C. tetani show much less genetic diversity than C. botulinum strains and because widespread vaccination efforts have reduced the public health threat from tetanus. Our aim was to acquire genomic data on the U.S. vaccine strain of C. tetani to better understand its genetic relationship to previously published genomic data from European vaccine strains. We performed high throughput genomic sequence analysis on two wild-type and two vaccine C. tetani strains. Comparative genomic analysis was performed using these and previously published genomic data for seven other C. tetani strains. Our analysis focused on single nucleotide polymorphisms (SNP and four distinct constituents of the mobile genome (mobilome: a hypervariable flagellar glycosylation island region, five conserved bacteriophage insertion regions, variations in three CRISPR (clustered regularly interspaced short palindromic repeats-Cas (CRISPR-associated systems, and a single plasmid. Intact type IA and IB CRISPR/Cas systems were within 10 of 11 strains. A type IIIA CRISPR/Cas system was present in two strains. Phage infection histories derived from CRISPR-Cas sequences indicate C. tetani encounters phages common among commensal gut bacteria and soil-borne organisms consistent with C. tetani distribution in nature. All vaccine strains form a clade distinct from currently sequenced wild type strains when considering variations in these mobile elements. SNP, flagellar glycosylation island, prophage content and CRISPR/Cas phylogenic histories provide tentative evidence suggesting vaccine and wild type strains share a

  8. Comparative pathogenomics of Clostridium tetani.

    Science.gov (United States)

    Cohen, Jonathan E; Wang, Rong; Shen, Rong-Fong; Wu, Wells W; Keller, James E

    2017-01-01

    Clostridium tetani and Clostridium botulinum produce two of the most potent neurotoxins known, tetanus neurotoxin and botulinum neurotoxin, respectively. Extensive biochemical and genetic investigation has been devoted to identifying and characterizing various C. botulinum strains. Less effort has been focused on studying C. tetani likely because recently sequenced strains of C. tetani show much less genetic diversity than C. botulinum strains and because widespread vaccination efforts have reduced the public health threat from tetanus. Our aim was to acquire genomic data on the U.S. vaccine strain of C. tetani to better understand its genetic relationship to previously published genomic data from European vaccine strains. We performed high throughput genomic sequence analysis on two wild-type and two vaccine C. tetani strains. Comparative genomic analysis was performed using these and previously published genomic data for seven other C. tetani strains. Our analysis focused on single nucleotide polymorphisms (SNP) and four distinct constituents of the mobile genome (mobilome): a hypervariable flagellar glycosylation island region, five conserved bacteriophage insertion regions, variations in three CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) systems, and a single plasmid. Intact type IA and IB CRISPR/Cas systems were within 10 of 11 strains. A type IIIA CRISPR/Cas system was present in two strains. Phage infection histories derived from CRISPR-Cas sequences indicate C. tetani encounters phages common among commensal gut bacteria and soil-borne organisms consistent with C. tetani distribution in nature. All vaccine strains form a clade distinct from currently sequenced wild type strains when considering variations in these mobile elements. SNP, flagellar glycosylation island, prophage content and CRISPR/Cas phylogenic histories provide tentative evidence suggesting vaccine and wild type strains share a common ancestor.

  9. A note on the complexity of finding and enumerating elementary modes.

    NARCIS (Netherlands)

    Acuna, V.; Marchetti-Spaccamela, A.; Sagot, M.-F.; Stougie, L.

    2010-01-01

    In the context of the study into elementary modes of metabolic networks, we prove two complexity results. Enumerating elementary modes containing a specific reaction is hard in an enumeration complexity sense. The decision problem if there exists an elementary mode containing two specific reactions

  10. 21 CFR 866.4700 - Automated fluorescence in situ hybridization (FISH) enumeration systems.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automated fluorescence in situ hybridization (FISH... Laboratory Equipment and Reagents § 866.4700 Automated fluorescence in situ hybridization (FISH) enumeration... Hybridization (FISH) Enumeration Systems.” See § 866.1(e) for the availability of this guidance document. [70 FR...

  11. Postpartum Clostridium sordellii infection associated with fatal toxic shock syndrome

    DEFF Research Database (Denmark)

    Rørbye, C; Petersen, Ina Sleimann; Nilas, Lisbeth

    2000-01-01

    Clostridium bacteria are anaerobic Gram positive spore-form-ing bacilli, known to cause distinct clinical syndromes such as botulism, tetanus, pseudomembranous colitis and myonecrosis. The natural habitats of Clostridium species are soil, water and the gastrointestinal tract of animals and humans....... In 5-10% of all women, Clostridium species are also found to be normal inhabitants in the microbial flora of the female genital tract. In case of a non-sexually transmitted genital tract infection, Clostridium species are isolated in 4-20%, and clostridium welchii seems to be the most common isolate....... Clostridium sordellii is rarely encountered in clinical specimens (1% of Clostridium species), but it has been described as a human pathogen with fatal potential. Two toxins, a lethal and a hemorrhagic (that antigenically and pathophysiologically appear similar to Clostridium difficile toxins B and A...

  12. Inactivation of viable Ascaris eggs by reagents during enumeration.

    Science.gov (United States)

    Nelson, K L; Darby, J L

    2001-12-01

    Various reagents commonly used to enumerate viable helminth eggs from wastewater and sludge were evaluated for their potential to inactivate Ascaris eggs under typical laboratory conditions. Two methods were used to enumerate indigenous Ascaris eggs from sludge samples. All steps in the methods were the same except that in method I a phase extraction step with acid-alcohol (35% ethanol in 0.1 N H(2)SO(4)) and diethyl ether was used whereas in method II the extraction step was avoided by pouring the sample through a 38-microm-mesh stainless steel sieve that retained the eggs. The concentration of eggs and their viability were lower in the samples processed by method I than in the samples processed by method II by an average of 48 and 70%, respectively. A second set of experiments was performed using pure solutions of Ascaris suum eggs to elucidate the effect of the individual reagents and relevant combination of reagents on the eggs. The percentages of viable eggs in samples treated with acid-alcohol alone and in combination with diethyl ether or ethyl acetate were 52, 27, and 4%, respectively, whereas in the rest of the samples the viability was about 80%. Neither the acid nor the diethyl ether alone caused any decrease in egg viability. Thus, the observed inactivation was attributed primarily to the 35% ethanol content of the acid-alcohol solution. Inactivation of the eggs was prevented by limiting the direct exposure to the extraction reagents to 30 min and diluting the residual concentration of acid-alcohol in the sample by a factor of 100 before incubation. Also, the viability of the eggs was maintained if the acid-alcohol solution was replaced with an acetoacetic buffer. None of the reagents used for the flotation step of the sample cleaning procedure (ZnSO(4), MgSO(4), and NaCl) or during incubation (0.1 N H(2)SO(4) and 0.5% formalin) inactivated the Ascaris eggs under the conditions studied.

  13. Polyclonal Antibody Therapies for Clostridium difficile Infection

    Directory of Open Access Journals (Sweden)

    Michael R. Simon

    2014-10-01

    Full Text Available Clostridium difficile infection has emerged as a growing worldwide health problem. The colitis of Clostridium difficile infection results from the synergistic action of C. difficile secreted toxins A and B upon the colon mucosa. A human monoclonal IgG anti-toxin has demonstrated the ability in combination therapy to reduce mortality in C. difficile challenged hamsters. This antibody is currently in a clinical trial for the treatment of human Clostridium difficile infection. More than one group of investigators has considered using polyclonal bovine colostral antibodies to toxins A and B as an oral passive immunization. A significant proportion of the healthy human population possesses polyclonal antibodies to the Clostridium difficile toxins. We have demonstrated that polyclonal IgA derived from the pooled plasma of healthy donors possesses specificity to toxins A and B and can neutralize these toxins in a cell-based assay. This suggests that secretory IgA prepared from such pooled plasma IgA may be able to be used as an oral treatment for Clostridium difficile infection.

  14. Using pattern enumeration to accelerate process development and ramp yield

    Science.gov (United States)

    Zhuang, Linda; Pang, Jenny; Xu, Jessy; Tsai, Mengfeng; Wang, Amy; Zhang, Yifan; Sweis, Jason; Lai, Ya-Chieh; Ding, Hua

    2016-03-01

    During a new technology node process setup phase, foundries do not initially have enough product chip designs to conduct exhaustive process development. Different operational teams use manually designed simple test keys to set up their process flows and recipes. When the very first version of the design rule manual (DRM) is ready, foundries enter the process development phase where new experiment design data is manually created based on these design rules. However, these IP/test keys contain very uniform or simple design structures. This kind of design normally does not contain critical design structures or process unfriendly design patterns that pass design rule checks but are found to be less manufacturable. It is desired to have a method to generate exhaustive test patterns allowed by design rules at development stage to verify the gap of design rule and process. This paper presents a novel method of how to generate test key patterns which contain known problematic patterns as well as any constructs which designers could possibly draw based on current design rules. The enumerated test key patterns will contain the most critical design structures which are allowed by any particular design rule. A layout profiling method is used to do design chip analysis in order to find potential weak points on new incoming products so fab can take preemptive action to avoid yield loss. It can be achieved by comparing different products and leveraging the knowledge learned from previous manufactured chips to find possible yield detractors.

  15. Update on Clostridium difficile infections.

    Science.gov (United States)

    Le Monnier, A; Zahar, J-R; Barbut, F

    2014-08-01

    Clostridium difficile infections (CDI) occur primarily in hospitalized patients with risk factors such as concomitant or recent use of antibiotics. CDI related additional costs are important for the global population and health-care facilities. CDI epidemiology has changed since 2003: they became more frequent boosted by large outbreaks, more severe, more resistant to antibiotic treatment, and spread to new groups of population without any risk factor. This is partly due to the emergence and worldwide dissemination of new and more virulent C. difficile strains such as the epidemic clone 027/NAP1/BI. The host immune response plays a central role in the pathogenesis of CDI and could also be involved in the occurrence of recurrent or severe forms. New guidelines including new molecular tests (NAAT) have recently clarified and simplified the diagnostic strategies for the microbiological diagnosis of CDI. The CDI incidence was proven to be related to the level of clinical suspicion and the frequency of microbiological screening for C. difficile. The current recommendations for the treatment of CDI mention oral metronidazole as the first line treatment for mild to moderate diarrhea. Oral vancomycin use should be restricted to severe cases. In the absence of consensus, the treatment of multiple recurrences remains a major concern. New and more targeted antibiotics and innovative therapeutic strategies (fecal transplantation, monoclonal antibodies, and vaccination) have emerged as new therapies for CDI. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  16. Epidemiology of Clostridium difficile Infection

    Science.gov (United States)

    DePestel, Daryl D.; Aronoff, David M.

    2014-01-01

    There has been dramatic change in the epidemiology of Clostridium difficile infection (CDI) since the turn of the 21st Century noted by a marked increase in incidence and severity, occurring at a disproportionately higher frequency in older patients. Historically considered a nosocomial infection associated with antibiotic exposure, CDI has now also emerged in the community in populations previously considered low risk. Emerging risk factors and disease recurrence represent continued challenges in the management of CDI. The increased incidence and severity associated with CDI has coincided with the emergence and rapid spread of a previously rare strain, ribotype 027. Recent data from the U.S. and Europe suggest the incidence of CDI may have reached a crescendo in recent years and is perhaps beginning to plateau. The acute-care direct costs of CDI were estimated to be $4.8 billion in 2008. However, nearly all the published studies have focused on CDI diagnosed and treated in acute-care hospital setting and fail to measure the burden outside the hospital, including recently discharged patients, outpatients, and those in long-term care facilities. Enhanced surveillance methods are needed to monitor the incidence, identify populations at risk, and characterize the molecular epidemiology of strains causing CDI. PMID:24064435

  17. Taking a(c)count of eye movements: Multiple mechanisms underlie fixations during enumeration.

    Science.gov (United States)

    Paul, Jacob M; Reeve, Robert A; Forte, Jason D

    2017-03-01

    We habitually move our eyes when we enumerate sets of objects. It remains unclear whether saccades are directed for numerosity processing as distinct from object-oriented visual processing (e.g., object saliency, scanning heuristics). Here we investigated the extent to which enumeration eye movements are contingent upon the location of objects in an array, and whether fixation patterns vary with enumeration demands. Twenty adults enumerated random dot arrays twice: first to report the set cardinality and second to judge the perceived number of subsets. We manipulated the spatial location of dots by presenting arrays at 0°, 90°, 180°, and 270° orientations. Participants required a similar time to enumerate the set or the perceived number of subsets in the same array. Fixation patterns were systematically shifted in the direction of array rotation, and distributed across similar locations when the same array was shown on multiple occasions. We modeled fixation patterns and dot saliency using a simple filtering model and show participants judged groups of dots in close proximity (2°-2.5° visual angle) as distinct subsets. Modeling results are consistent with the suggestion that enumeration involves visual grouping mechanisms based on object saliency, and specific enumeration demands affect spatial distribution of fixations. Our findings highlight the importance of set computation, rather than object processing per se, for models of numerosity processing.

  18. Ammonia production by human faecal bacteria, and the enumeration, isolation and characterization of bacteria capable of growth on peptides and amino acids

    Directory of Open Access Journals (Sweden)

    Richardson Anthony J

    2013-01-01

    Full Text Available Abstract Background The products of protein breakdown in the human colon are considered to be detrimental to gut health. Amino acid catabolism leads to the formation of sulfides, phenolic compounds and amines, which are inflammatory and/or precursors to the formation of carcinogens, including N-nitroso compounds. The aim of this study was to investigate the kinetics of protein breakdown and the bacterial species involved. Results Casein, pancreatic casein hydrolysate (mainly short-chain peptides or amino acids were incubated in vitro with suspensions of faecal bacteria from 3 omnivorous and 3 vegetarian human donors. Results from the two donor groups were similar. Ammonia production was highest from peptides, followed by casein and amino acids, which were similar. The amino acids metabolized most extensively were Asp, Ser, Lys and Glu. Monensin inhibited the rate of ammonia production from amino acids by 60% (P = 0.001, indicating the involvement of Gram-positive bacteria. Enrichment cultures were carried out to investigate if, by analogy with the rumen, there was a significant population of asaccharolytic, obligately amino acid-fermenting bacteria (‘hyper-ammonia-producing’ bacteria; HAP in the colon. Numbers of bacteria capable of growth on peptides or amino acids alone averaged 3.5% of the total viable count, somewhat higher than the rumen. None of these were HAP, however. The species enriched included Clostridium spp., one of which was C. perfringens, Enterococcus, Shigella and Escherichia coli. Conclusions Protein fermentation by human faecal bacteria in the absence of sugars not only leads to the formation of hazardous metabolic products, but also to the possible proliferation of harmful bacteria. The kinetics of protein metabolism were similar to the rumen, but HAP bacteria were not found.

  19. Rapid detection, characterization, and enumeration of foodborne pathogens.

    Science.gov (United States)

    Hoorfar, J

    2011-11-01

    As food safety management further develops, microbiological testing will continue to play an important role in assessing whether Food Safety Objectives are achieved. However, traditional microbiological culture-based methods are limited, particularly in their ability to provide timely data. The present review discusses the reasons for the increasing interest in rapid methods, current developments in the field, the research needs, and the future trends. The advent of biotechnology has introduced new technologies that led to the emergence of rapid diagnostic methods and altered food testing practices. Rapid methods are comprised of many different detection technologies, including specialized enzyme substrates, antibodies and DNA, ranging from simple differential plating media to the use of sophisticated instruments. The use of non-invasive sampling techniques for live animals especially came into focus with the 1990s outbreak of bovine spongiform encephalopathy that was linked to the human outbreak of Creutzfeldt Jakob's Disease. Serology is still an important tool in preventing foodborne pathogens to enter the human food supply through meat and milk from animals. One of the primary uses of rapid methods is for fast screening of large number of samples, where most of them are expected to be test-negative, leading to faster product release for sale. This has been the main strength of rapid methods such as real-time Polymerase Chain Reaction (PCR). Enrichment PCR, where a primary culture broth is tested in PCR, is the most common approach in rapid testing. Recent reports show that it is possible both to enrich a sample and enumerate by pathogen-specific real-time PCR, if the enrichment time is short. This can be especially useful in situations where food producers ask for the level of pathogen in a contaminated product. Another key issue is automation, where the key drivers are miniaturization and multiple testing, which mean that not only one instrument is flexible

  20. Óleo essencial de orégano, alecrim, canela e extrato de pimenta no controle de Salmonella, Eimeria e Clostridium em frangos de corte

    Directory of Open Access Journals (Sweden)

    Tânia D.M.M. Bona

    2012-05-01

    Full Text Available Este trabalho foi conduzido com o objetivo de avaliar a eficiência de um composto vegetal contendo óleo essencial de orégano, alecrim, canela e extrato de pimenta vermelha no controle de Salmonella, Eimeria e Clostridium em frangos de corte. Para tal, foram realizados dois experimentos. No primeiro avaliou-se a eficiência deste produto no controle de Clostridium perfringens após desafio com Eimeria acervulina, E. maxima e E. tenella. Aves de um dia de idade foram divididas em três grupos: T1 - dieta controle sem aditivo promotor de crescimento; T2 - dieta com adição de avilamicina (10ppm; e T3 - dieta com adição do composto vegetal (100ppm. O uso do composto vegetal na alimentação de frangos reduziu lesões específicas de E. maxima e E. tenella aos 14 dias pós-inoculação (PI como também reduziram a contagem de unidades formadoras de colônias (UFC de Clostridium perfringens no conteúdo do ceco das aves em relação ao grupo controle. No segundo experimento avaliou-se a eficiência deste mesmo produto em aves desafiadas com Salmonella Enteritidis. Aves de um dia de idade foram distribuídas em três tratamentos, sendo T1 - dieta controle sem adição de antibiótico promotor de crescimento, T2 - dieta com 10ppm de Avilamicina, T3 - dieta com 100ppm de um produto a base do composto vegetal acima citado. Aos 21 dias de idade todas as aves foram inoculadas com 10(5 UFC de Salmonella Enteritidis. A utilização do composto vegetal e avilamicina diminuiu a excreção de Salmonella nas aves 72 horas PI de Salmonella. A utilização do composto vegetal aumentou a relação vilo/células CD3+ no duodeno, em relação ao grupo avilamicina e controle, porém não teve efeito sobre a expressão destas células no ceco.

  1. Description of Clostridium phoceensis sp. nov., a new species within the genus Clostridium

    Directory of Open Access Journals (Sweden)

    M. Hosny

    2016-11-01

    Full Text Available Clostridium phoceensis sp. nov., strain GD3T (= CSUR P1929 = DSM 100334 is the type strain of C. phoceensis sp. nov., a new species within the genus Clostridium. This strain was isolated from the gut microbiota of a 28-year-old healthy French man. C. phoceensis is a Gram-negative, spore-forming, nonmotile, strictly anaerobic bacterium. We describe its complete genome sequence and annotation, together with its phenotypic characteristics.

  2. Flagellar glycosylation in Clostridium botulinum.

    Science.gov (United States)

    Twine, Susan M; Paul, Catherine J; Vinogradov, Evgeny; McNally, David J; Brisson, Jean-Robert; Mullen, James A; McMullin, David R; Jarrell, Harold C; Austin, John W; Kelly, John F; Logan, Susan M

    2008-09-01

    Flagellins from Clostridium botulinum were shown to be post-translationally modified with novel glycan moieties by top-down MS analysis of purified flagellin protein from strains of various toxin serotypes. Detailed analyses of flagellin from two strains of C. botulinum demonstrated that the protein is modified by a novel glycan moiety of mass 417 Da in O-linkage. Bioinformatic analysis of available C. botulinum genomes identified a flagellar glycosylation island containing homologs of genes recently identified in Campylobacter coli that have been shown to be responsible for the biosynthesis of legionaminic acid derivatives. Structural characterization of the carbohydrate moiety was completed utilizing both MS and NMR spectroscopy, and it was shown to be a novel legionaminic acid derivative, 7-acetamido-5-(N-methyl-glutam-4-yl)-amino-3,5,7,9-tetradeoxy-D-glycero-alpha-D-galacto-nonulosonic acid, (alphaLeg5GluNMe7Ac). Electron transfer dissociation MS with and without collision-activated dissociation was utilized to map seven sites of O-linked glycosylation, eliminating the need for chemical derivatization of tryptic peptides prior to analysis. Marker ions for novel glycans, as well as a unique C-terminal flagellin peptide marker ion, were identified in a top-down analysis of the intact protein. These ions have the potential for use in for rapid detection and discrimination of C. botulinum cells, indicating botulinum neurotoxin contamination. This is the first report of glycosylation of Gram-positive flagellar proteins by the 'sialic acid-like' nonulosonate sugar, legionaminic acid.

  3. Clostridium difficile infection in Thailand.

    Science.gov (United States)

    Putsathit, Papanin; Kiratisin, Pattarachai; Ngamwongsatit, Puriya; Riley, Thomas V

    2015-01-01

    Clostridium difficile is the aetiological agent in ca. 20% of cases of antimicrobial-associated diarrhoea in hospitalised adults. Diseases caused by this organism range from mild diarrhoea to occasional fatal pseudomembranous colitis. The epidemiology of C. difficile infection (CDI) has changed notably in the past decade, following epidemics in the early 2000s of PCR ribotype (RT) 027 infection in North America and Europe, where there was an increase in disease severity and mortality. Another major event has been the emergence of RT 078, initially as the predominant ribotype in production animals in the USA and Europe, and then in humans in Europe. Although there have been numerous investigations of the epidemiology of CDI in North America and Europe, limited studies have been undertaken elsewhere, particularly in Asia. Antimicrobial exposure remains the major risk factor for CDI. Given the high prevalence of indiscriminate and inappropriate use of antimicrobials in Asia, it is conceivable that CDI is relatively common among humans and animals. This review describes the level of knowledge in Thailand regarding C. difficile detection methods, prevalence and antimicrobial susceptibility profile, as well as the clinical features of, treatment options for and outcomes of the disease. In addition, antimicrobial usage in livestock in Thailand will be reviewed. A literature search yielded 18 studies mentioning C. difficile in Thailand, a greater number than from any other Asian country. It is possible that the situation in Thailand in relation to CDI may mirror the situation in other developing Asians countries. Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  4. Veal calves produce less antibodies against C. perfringens alpha toxin compared to beef calves

    OpenAIRE

    Valgaeren, Bonnie; Pardon, Bart; Goossens, Evy; Verherstraeten, Stefanie; Roelandt, Sophie; Timbermont, Leen; Van Der Vekens, Nicky; Stuyvaert, Sabrina; Gille, Linde; Van Driessche, Laura; Haesebrouck, Freddy; Ducatelle, Richard; Van Immerseel, Filip; Deprez, Piet

    2015-01-01

    Enterotoxaemia is a disease with a high associated mortality rate, affecting beef and veal calves worldwide, caused by C. perfringens alpha toxin and perfringolysin. A longitudinal study was conducted to determine the dynamics of antibodies against these toxins in 528 calves on 4 beef and 15 veal farms. The second study aimed to determine the effect of solid feed intake on the production of antibodies against alpha toxin and perfringolysin. The control group only received milk replacer, wher...

  5. Method to enumerate oocysts of cryptosporidium and cysts of Giardia in water

    International Nuclear Information System (INIS)

    Briancesco, R.; Bonadonna, L.

    2000-01-01

    Cryptosporidium and Giardia have been recognized as etiological agents of gastrointestinal illness in humans with severe consequences on children and immunocompromised individuals. Water seems to be vehicle of infection. In last years many efforts have been done to evaluate a method to enumerate oocysts of Cryptosporidium and cysts of Giardia in waters. Throughout filtration and concentration steps, the two procedures proposed allow to enumerate oocysts and cysts belonging to the two genera of protozoa [it

  6. Clostridium difficile and pediatric inflammatory bowel disease

    DEFF Research Database (Denmark)

    Martinelli, Massimo; Strisciuglio, Caterina; Veres, Gabor

    2014-01-01

    BACKGROUND: Clostridium difficile infection is associated with pediatric inflammatory bowel disease (IBD) in several ways. We sought to investigate C. difficile infection in pediatric patients with IBD in comparison with a group of children with celiac disease and to evaluate IBD disease course o...

  7. Clostridium cadaveris bacteraemia: two cases and review.

    NARCIS (Netherlands)

    Schade, R.P.; Rijn, M. Van; Timmers, H.J.L.M.; Dofferhoff, A.S.M.; Klaassen, C.H.W.; Meis, J.F.G.M.

    2006-01-01

    Clostridium cadaveris is a strict anaerobic Gram-positive rod that is the most prominent bacterium during the decay of dead bodies. We present 2 rare cases of bacteraemia with C. cadaveris. The source of both infectious episodes was most probably of gastrointestinal origin.

  8. Clostridium difficile infection : epidemiology, complications and recurrences

    NARCIS (Netherlands)

    Bauer, Martijn Philippe

    2014-01-01

    Clostridium difficile is a spore-forming bacterium, the toxin-producing strains of which cause colitis. Risk factors are antibiotics, advanced age and severe comorbidity. C. difficile infection (CDI) has been regarded as mostly a hospital-acquired infection. Preventing relapses is considered the

  9. The changing epidemiology of Clostridium difficile infections

    NARCIS (Netherlands)

    Freeman, J.; Bauer, M. P.; Baines, S. D.; Corver, J.; Fawley, W. N.; Goorhuis, B.; Kuijper, E. J.; Wilcox, M. H.

    2010-01-01

    The epidemiology of Clostridium difficile infection (CDI) has changed dramatically during this millennium. Infection rates have increased markedly in most countries with detailed surveillance data. There have been clear changes in the clinical presentation, response to treatment, and outcome of CDI.

  10. Clostridium difficile infection in returning travellers

    NARCIS (Netherlands)

    Michal Stevens, A.; Esposito, Douglas H.; Stoney, Rhett J.; Hamer, Davidson H.; Flores-Figueroa, Jose; Bottieau, Emmanuel; Connor, Bradley A.; Gkrania-Klotsas, Effrossyni; Goorhuis, Abraham; Hynes, Noreen A.; Libman, Michael; Lopez-Velez, Rogelio; McCarthy, Anne E.; von Sonnenburg, Frank; Schwartz, Eli; van Genderen, Perry J. J.; Scott Benson, L.; Leung, Daniel T.

    2017-01-01

    There is increasing recognition of the contribution of community-acquired cases to the global burden of Clostridium difficile infection (CDI). The epidemiology of CDI among international travellers is poorly understood, and factors associated with international travel, such as antibiotic use and

  11. Comparação entre hipoclorito de sódio e ácido peracético na inativação de E. coli, colifagos e C. perfringens em água com elevada concentração de matéria orgânica Comparison between sodium hipoclorite and peracetic acid for E. coli, coliphages and C. perfringens inactivation of high organic matter concentration water

    Directory of Open Access Journals (Sweden)

    Jeanette Beber de Souza

    2005-06-01

    Full Text Available Foi realizado estudo comparativo em condições experimentais similares, entre hipoclorito de sódio e ácido peracético na desinfecção de água com elevada concentração de matéria orgânica. O conteúdo de carbono orgânico dissolvido (COD variou de 4,652 a 30,13 mgC/L para a água de estudo bruta e após a desinfecção esses valores variaram de 5,105 a 26,16 mgC/L para os ensaios com cloro e de 15,89 a 32,78 mgC/L para os ensaios com ácido peracético. O desempenho dos dois desinfetantes foi avaliado segundo a inativação de três microrganismos indicadores, Escherichia coli ATCC 11229, colifagos e Clostridium perfringens ATCC 13124 que eram previamente cultivados e inoculados à água no momento do experimento. As concentrações aplicadas de cloro e ácido peracético foram de 2,0; 3,0; 4,0 e 5,0 mg/L e os tempos de contato de 5, 10, 15 e 20 minutos. Para 3,0 mg/L de cloro aplicado, obteve-se 3 log de inativação de E. coli em 20 minutos de contato, 2,92 log de inativação de fagos em 10 minutos e 2 log de inativação de C. perfringens em 15 minutos. Os resultados dos ensaios de desinfecção com ácido peracético indicaram efetiva inativação dos microrganismos indicadores empregados, mesmo na presença de elevada concentração de matéria orgânica. Para 5,0 mg/L de ácido peracético aplicado e 15 minutos de contato, inativações de E. coli maiores que 6 log, de fagos maiores que 5 log em 20 minutos e de C. perfringens maiores que 4 log em 10 minutos de contato foram alcançadas.The research comparing the action of sodium hypochlorite and peracetic acid to disinfect drinking water with high concentration organic matter was carried out in similar conditions. The dissolved organic carbon (DOC concentration was from 4.652 to 30.13 mg/L in raw water, from 5.105 to 26.16 mg/L in water disinfected with chlorine and from 15.89 to 32.72 mg/L in water disinfected with peracetic acid. The efficiency of the two disinfectants was

  12. Template-based combinatorial enumeration of virtual compound libraries for lipids.

    Science.gov (United States)

    Sud, Manish; Fahy, Eoin; Subramaniam, Shankar

    2012-09-25

    A variety of software packages are available for the combinatorial enumeration of virtual libraries for small molecules, starting from specifications of core scaffolds with attachments points and lists of R-groups as SMILES or SD files. Although SD files include atomic coordinates for core scaffolds and R-groups, it is not possible to control 2-dimensional (2D) layout of the enumerated structures generated for virtual compound libraries because different packages generate different 2D representations for the same structure. We have developed a software package called LipidMapsTools for the template-based combinatorial enumeration of virtual compound libraries for lipids. Virtual libraries are enumerated for the specified lipid abbreviations using matching lists of pre-defined templates and chain abbreviations, instead of core scaffolds and lists of R-groups provided by the user. 2D structures of the enumerated lipids are drawn in a specific and consistent fashion adhering to the framework for representing lipid structures proposed by the LIPID MAPS consortium. LipidMapsTools is lightweight, relatively fast and contains no external dependencies. It is an open source package and freely available under the terms of the modified BSD license.

  13. TREATMENT OF CLOSTRIDIUM DIFFICILE- ASSOCIATED DISEASE

    Directory of Open Access Journals (Sweden)

    Snezana Antic-Mladenovic

    2007-04-01

    Full Text Available Clostridium difficile is a Gram-positive, spore-forming, anaerobic bacillus that is widely distributed in the environment, but is found as a part of a normal large bowel flora in approximately 3% of normal adults. C. difficile produces two protein exotoxins: toxin A and toxin B. Both toxins are responsible for causing the sings and symptoms of disease.C. difficile is now thought to be responsible for a spectrum of diseases, ranging from asymptomatic colonization to diarrhea of varying severity, life-threatening colitis, often as a consequence of long-term antibiotic exposure. This spectrum has become known as C. difficile-associated disease (CDAD.Treatment of Clostridium difficile-associated disease demand administration of effi-cient antibiotics (vancomycin, metronidazole, anion exchange resins and probiotics (Lactobacillus spp., Saccharomyces boulardii.

  14. New techniques for growing anaerobic bacteria: experiments with Clostridium butyricum and Clostridium acetobutylicum

    International Nuclear Information System (INIS)

    Adler, H.I.; Crow, W.D.; Hadden, C.T.; Hall, J.; Machanoff, R.

    1983-01-01

    Stable membrane fragments derived from Escherichia coli produce and maintain strict anaerobic conditions when added to liquid or solid bacteriological media. Techniques for growing Clostridium butyricum and Clostridium acetobutylicum in membrane-containing media are described. Liquid cultures initiated by very small inocula can be grown in direct contact with air. In solid media, colonies develop rapidly from individual cells even without incubation in anaerobic jars or similar devices. Observations on growth rates, spontaneous mutations, radiation, and oxygen sensitivity of anaerobic bacteria have been made using these new techniques

  15. The isolation, enumeration, and characterization of Rhizobium bacteria of the soil in Wamena Biological Garden

    Directory of Open Access Journals (Sweden)

    SRI PURWANINGSIH

    2005-04-01

    Full Text Available The eleven soil samples have been isolated and characterized. The aims of the study were to get the pure culture and some data which described about enumeration and especially their characters in relation to the acids and bases reaction in their growth. The isolation of the bacteria use Yeast Extract Mannitol Agar medium (YEMA while the characterization by using YEMA medium mixed with Brom Thymol Blue and Congo Red indicators respectively. The results showed that eighteen isolates have been isolated which consisted of three low growing and fifteen fast growing bacteria. Two isolates were not indicated Rhizobium and sixteen were Rhizobium. Density of Rhizobium enumeration was varied which related to soil organic matter content. The enumeration bacteria in YEMA medium were in the range of 0.6 x 105 and 11.6 x 105 CFU /g soil. The highest population was found in soil sample of Wieb vegetation.

  16. Summary of the Skookumchuck Creek bull trout enumeration project 2001.; TOPICAL

    International Nuclear Information System (INIS)

    Baxter, James S.; Baxter, Jeremy

    2002-01-01

    This report summarizes the second year of a bull trout (Salvelinus confluentus) enumeration project on Skookumchuck Creek in southeastern British Columbia. An enumeration fence and traps were installed on the creek from September 6th to October 12th 2001 to enable the capture of post-spawning bull trout emigrating out of the watershed. During the study period, a total of 273 bull trout were sampled through the enumeration fence. Length and weight were determined for all bull trout captured. In total, 39 fish of undetermined sex, 61 males and 173 females were processed through the fence. An additional 19 bull trout were observed on a snorkel survey prior to the fence being removed on October 12th. Coupled with the fence count, the total bull trout enumerated during this project was 292 fish. Several other species of fish were captured at the enumeration fence including westslope cutthroat trout (Oncorhynchus clarki lewisi), Rocky Mountain whitefish (Prosopium williamsoni), and kokanee (O. nerka). A total of 143 bull trout redds were enumerated on the ground in two different locations (river km 27.5-30.5, and km 24.0-25.5) on October 3rd. The majority of redds (n=132) were observed in the 3.0 km index section (river km 27.5-30.5) that has been surveyed over the past five years. The additional 11 redds were observed in a 1.5 km section (river km 24.0-25.5). Summary plots of water temperature for Bradford Creek, Sandown Creek, Buhl Creek, and Skookumchuck Creek at three locations suggested that water temperatures were within the temperature range preferred by bull trout for spawning, egg incubation, and rearing

  17. Impact of enumeration method on diversity of Escherichia coli genotypes isolated from surface water.

    Science.gov (United States)

    Martin, E C; Gentry, T J

    2016-11-01

    There are numerous regulatory-approved Escherichia coli enumeration methods, but it is not known whether differences in media composition and incubation conditions impact the diversity of E. coli populations detected by these methods. A study was conducted to determine if three standard water quality assessments, Colilert ® , USEPA Method 1603, (modified mTEC) and USEPA Method 1604 (MI), detect different populations of E. coli. Samples were collected from six watersheds and analysed using the three enumeration approaches followed by E. coli isolation and genotyping. Results indicated that the three methods generally produced similar enumeration data across the sites, although there were some differences on a site-by-site basis. The Colilert ® method consistently generated the least diverse collection of E. coli genotypes as compared to modified mTEC and MI, with those two methods being roughly equal to each other. Although the three media assessed in this study were designed to enumerate E. coli, the differences in the media composition, incubation temperature, and growth platform appear to have a strong selective influence on the populations of E. coli isolated. This study suggests that standardized methods of enumeration and isolation may be warranted if researchers intend to obtain individual E. coli isolates for further characterization. This study characterized the impact of three USEPA-approved Escherichia coli enumeration methods on observed E. coli population diversity in surface water samples. Results indicated that these methods produced similar E. coli enumeration data but were more variable in the diversity of E. coli genotypes observed. Although the three methods enumerate the same species, differences in media composition, growth platform, and incubation temperature likely contribute to the selection of different cultivable populations of E. coli, and thus caution should be used when implementing these methods interchangeably for

  18. Management of Clostridium difficile diarrhoea in District General ...

    African Journals Online (AJOL)

    ... four cases of Clostridium difficile in our hospital over duration of three months. We looked into the demographic features of the patient population and compliance with the Trust guidelines for the management of the diarrhoea. Keywords:Diarrhoea, Clostridium difficile, Management. Internet Journal of Medical Update Vol.

  19. Clostridium difficile: A healthcare-associated infection of unknown ...

    African Journals Online (AJOL)

    Clostridium difficile: A healthcare-associated infection of unknown significance in adults in sub-Saharan Africa. ... Abstract. Background: Clostridium difficile infection (CDI) causes a high burden of disease in high-resource healthcare systems, with significant morbidity, mortality, and financial implications. CDI is a ...

  20. Plasmidome interchange between Clostridium botulinum, Clostridium novyi and Clostridium haemolyticum converts strains of independent lineages into distinctly different pathogens.

    Science.gov (United States)

    Skarin, Hanna; Segerman, Bo

    2014-01-01

    Clostridium botulinum (group III), Clostridium novyi and Clostridium haemolyticum are well-known pathogens causing animal botulism, gas gangrene/black disease, and bacillary hemoglobinuria, respectively. A close genetic relationship exists between the species, which has resulted in the collective term C. novyi sensu lato. The pathogenic traits in these species, e.g., the botulinum neurotoxin and the novyi alpha toxin, are mainly linked to a large plasmidome consisting of plasmids and circular prophages. The plasmidome of C. novyi sensu lato has so far been poorly characterized. In this study we explored the genomic relationship of a wide range of strains of C. novyi sensu lato with a special focus on the dynamics of the plasmidome. Twenty-four genomes were sequenced from strains selected to represent as much as possible the genetic diversity in C. novyi sensu lato. Sixty-one plasmids were identified in these genomes and 28 of them were completed. The genomic comparisons revealed four separate lineages, which did not strictly correlate with the species designations. The plasmids were categorized into 13 different plasmid groups on the basis of their similarity and conservation of plasmid replication or partitioning genes. The plasmid groups, lineages and species were to a large extent entwined because plasmids and toxin genes had moved across the lineage boundaries. This dynamic process appears to be primarily driven by phages. We here present a comprehensive characterization of the complex species group C. novyi sensu lato, explaining the intermixed genetic properties. This study also provides examples how the reorganization of the botulinum toxin and the novyi alpha toxin genes within the plasmidome has affected the pathogenesis of the strains.

  1. Plasmidome interchange between Clostridium botulinum, Clostridium novyi and Clostridium haemolyticum converts strains of independent lineages into distinctly different pathogens.

    Directory of Open Access Journals (Sweden)

    Hanna Skarin

    Full Text Available Clostridium botulinum (group III, Clostridium novyi and Clostridium haemolyticum are well-known pathogens causing animal botulism, gas gangrene/black disease, and bacillary hemoglobinuria, respectively. A close genetic relationship exists between the species, which has resulted in the collective term C. novyi sensu lato. The pathogenic traits in these species, e.g., the botulinum neurotoxin and the novyi alpha toxin, are mainly linked to a large plasmidome consisting of plasmids and circular prophages. The plasmidome of C. novyi sensu lato has so far been poorly characterized. In this study we explored the genomic relationship of a wide range of strains of C. novyi sensu lato with a special focus on the dynamics of the plasmidome. Twenty-four genomes were sequenced from strains selected to represent as much as possible the genetic diversity in C. novyi sensu lato. Sixty-one plasmids were identified in these genomes and 28 of them were completed. The genomic comparisons revealed four separate lineages, which did not strictly correlate with the species designations. The plasmids were categorized into 13 different plasmid groups on the basis of their similarity and conservation of plasmid replication or partitioning genes. The plasmid groups, lineages and species were to a large extent entwined because plasmids and toxin genes had moved across the lineage boundaries. This dynamic process appears to be primarily driven by phages. We here present a comprehensive characterization of the complex species group C. novyi sensu lato, explaining the intermixed genetic properties. This study also provides examples how the reorganization of the botulinum toxin and the novyi alpha toxin genes within the plasmidome has affected the pathogenesis of the strains.

  2. Enumeration versus Multiple Object Tracking: The Case of Action Video Game Players

    Science.gov (United States)

    Green, C. S.; Bavelier, D.

    2006-01-01

    Here, we demonstrate that action video game play enhances subjects' ability in two tasks thought to indicate the number of items that can be apprehended. Using an enumeration task, in which participants have to determine the number of quickly flashed squares, accuracy measures showed a near ceiling performance for low numerosities and a sharp drop…

  3. Miniaturized most probable number for the enumeration of Salmonella sp in artificially contaminated chicken meat

    Directory of Open Access Journals (Sweden)

    FL Colla

    2014-03-01

    Full Text Available Salmonella is traditionally identified by conventional microbiological tests, but the enumeration of this bacterium is not used on a routine basis. Methods such as the most probable number (MPN, which utilize an array of multiple tubes, are time-consuming and expensive, whereas miniaturized most probable number (mMPN methods, which use microplates, can be adapted for the enumeration of bacteria, saving up time and materials. The aim of the present paper is to assess two mMPN methods for the enumeration of Salmonella sp in artificially-contaminated chicken meat samples. Microplates containing 24 wells (method A and 96 wells (method B, both with peptone water as pre-enrichment medium and modified semi-solid Rappaport-Vassiliadis (MSRV as selective enrichment medium, were used. The meat matrix consisted of 25g of autoclaved ground chicken breast contaminated with dilutions of up to 10(6 of Salmonella Typhimurium (ST and Escherichia coli (EC. In method A, the dilution 10-5 of Salmonella Typhimurium corresponded to >57 MPN/mL and the dilution 10-6 was equal to 30 MPN/mL. There was a correlation between the counts used for the artificial contamination of the samples and those recovered by mMPN, indicating that the method A was sensitive for the enumeration of different levels of contamination of the meat matrix. In method B, there was no correlation between the inoculated dilutions and the mMPN results.

  4. Sieving for pseudosquares and pseudocubes in parallel using doubly-focused enumeration and wheel datastructures

    OpenAIRE

    Sorenson, Jonathan P.

    2010-01-01

    We extend the known tables of pseudosquares and pseudocubes, discuss the implications of these new data on the conjectured distribution of pseudosquares and pseudocubes, and present the details of the algorithm used to do this work. Our algorithm is based on the space-saving wheel data structure combined with doubly-focused enumeration, run in parallel on a cluster supercomputer.

  5. TEMA and Dot Enumeration Profiles Predict Mental Addition Problem Solving Speed Longitudinally.

    Science.gov (United States)

    Major, Clare S; Paul, Jacob M; Reeve, Robert A

    2017-01-01

    Different math indices can be used to assess math potential at school entry. We evaluated whether standardized math achievement (TEMA-2 performance), core number abilities (dot enumeration, symbolic magnitude comparison), non-verbal intelligence (NVIQ) and visuo-spatial working memory (VSWM), in combination or separately, predicted mental addition problem solving speed over time. We assessed 267 children's TEMA-2, magnitude comparison, dot enumeration, and VSWM abilities at school entry (5 years) and NVIQ at 8 years. Mental addition problem solving speed was assessed at 6, 8, and 10 years. Longitudinal path analysis supported a model in which dot enumeration performance ability profiles and previous mental addition speed predicted future mental addition speed on all occasions, supporting a componential account of math ability. Standardized math achievement and NVIQ predicted mental addition speed at specific time points, while VSWM and symbolic magnitude comparison did not contribute unique variance to the model. The implications of using standardized math achievement and dot enumeration ability to index math learning potential at school entry are discussed.

  6. Sample handling factors affecting the enumeration of lactobacilli and cellulolytic bacteria in equine feces

    Science.gov (United States)

    The objectives were to compare media types and evaluate the effects of fecal storage time and temperature on the enumeration of cellulolytic bacteria and lactobacilli from horses. Fecal samples were collected from horses (n = 3) and transported to the lab (CO2, 37 ºC, 0.5 h). The samples were assign...

  7. A comparison of test statistics for the recovery of rapid growth-based enumeration tests

    NARCIS (Netherlands)

    van den Heuvel, Edwin R.; IJzerman-Boon, Pieta C.

    This paper considers five test statistics for comparing the recovery of a rapid growth-based enumeration test with respect to the compendial microbiological method using a specific nonserial dilution experiment. The finite sample distributions of these test statistics are unknown, because they are

  8. Discontinuity in the Enumeration of Sequentially Presented Auditory and Visual Stimuli

    Science.gov (United States)

    Camos, Valerie; Tillmann, Barbara

    2008-01-01

    The seeking of discontinuity in enumeration was recently renewed because Cowan [Cowan, N. (2001). "The magical number 4 in short-term memory: A reconsideration of mental storage capacity." "Behavioral and Brain Sciences," 24, 87-185; Cowan, N. (2005). "Working memory capacity." Hove: Psychology Press] suggested that it allows evaluating the limit…

  9. Evaluation of culture media for selective enumeration of bifidobacteria and lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Judit Süle

    2014-09-01

    Full Text Available The purpose of this study was to test the suitability of Transgalactosylated oligosaccharides-mupirocin lithium salt (TOS-MUP and MRS-clindamycin-ciprofloxacin (MRS-CC agars, along with several other culture media, for selectively enumerating bifidobacteria and lactic acid bacteria (LAB species commonly used to make fermented milks. Pure culture suspensions of a total of 13 dairy bacteria strains, belonging to eight species and five genera, were tested for growth capability under various incubation conditions. TOS-MUP agar was successfully used for the selective enumeration of both Bifidobacterium animalis subsp. lactis BB-12 and B. breve M-16 V. MRS-CC agar showed relatively good selectivity for Lactobacillus acidophilus, however, it also promoted the growth of Lb. casei strains. For this reason, MRS-CC agar can only be used as a selective medium for the enumeration of Lb. acidophilus if Lb. casei is not present in a product at levels similar to or exceeding those of Lb. acidophilus. Unlike bifidobacteria and coccus-shaped LAB, all the lactobacilli strains involved in this work were found to grow well in MRS pH 5.4 agar incubated under anaerobiosis at 37 °C for 72 h. Therefore, this method proved to be particularly suitable for the selective enumeration of Lactobacillus spp.

  10. Comparison of selected methods for the enumeration of fecal coliforms and Escherichia coli in shellfish.

    Science.gov (United States)

    Grabow, W O; De Villiers, J C; Schildhauer, C I

    1992-09-01

    In a comparison of five selected methods for the enumeration of fecal coliforms and Escherichia coli in naturally contaminated and sewage-seeded mussels (Choromytilus spp.) and oysters (Ostrea spp.), a spread-plate procedure with mFC agar without rosolic acid and preincubation proved the method of choice for routine quality assessment.

  11. BACTERIOLOGICAL PROPERTIES OF MARINE WATER IN ADRIATIC FISH FARMS: ENUMERATION OF HETEROTROPHIC BACTERIA

    Directory of Open Access Journals (Sweden)

    Emin Teskeredžić

    2012-12-01

    Full Text Available Aquaculture is currently one of the fastest growing food production sectors in the world. Increase in nutrients and organic wastes lead to general deterioration of water quality. The problem of water quality is associated with both physical and chemical factors, as well as microbiological water quality. Heterotrophic bacteria play an important role in the process of decomposition of organic matter in water environment and indicate eutrophication process. Here we present our experience and knowledge on bacterial properties of marine water in the Adriatic fish farms with European sea bass (Dicentrarchus labrax L., 1758, with an emphasis on enumeration of heterotrophic bacteria in marine water. We applied two temperatures of incubation, as well as two methods for enumeration of heterotrophic bacteria: substrate SimPlate® test and spread plate method on conventional artificial media (Marine agar and Tryptic Soy agar with added NaCl. The results of analysis of bacteriological properties of marine water in the Adriatic fish farms showed that enumeration of heterotrophic bacteria in marine water depends on the applied incubation temperature and media for enumeration. At the same time, the incubation temperature of 22C favours more intense growth of marine heterotrophic bacteria, whereas a SimPlate test gives higher values of heterotrophic bacteria. Volatile values of heterotrophic bacteria during this research indicate a possible deterioration of microbiological water quality in the Adriatic fish farms and a need for regular monitoring of marine water quality.

  12. Enumeration of Mars years and seasons since the beginning of telescopic exploration

    Science.gov (United States)

    Piqueux, Sylvain; Byrne, Shane; Titus, Timothy N.; Hansen, Candice J.; Kieffer, Hugh H.

    2015-01-01

    A clarification for the enumeration of Mars Years prior to 1955 is presented, along with a table providing the Julian dates associated with Ls = 0° for Mars Years -183 (beginning of the telescopic study of Mars) to 100. A practical algorithm for computing Ls as a function of the Julian Date is provided. No new science results are presented

  13. Fluorogenic membrane overlays to enumerate total coliforms, Escherichia coli, and total Vibrionaceae in shellfish and seawater

    Science.gov (United States)

    Three assays were developed to enumerate total coliforms, Escherichia coli, and total Vibrionaceae in shellfish and other foods and in seawater and other environmental samples. Assays involve membrane overlays of overnight colonies on non-selective agar plates to detect ß-glucuronidase and lysyl am...

  14. Enumeration for spanning trees and forests of join graphs based on the combinatorial decomposition

    Directory of Open Access Journals (Sweden)

    Sung Sik U

    2016-10-01

    Full Text Available This paper discusses the enumeration for rooted spanning trees and forests of the labelled join graphs $K_m+H_n$ and $K_m+K_{n,p}$, where $H_n$ is a graph with $n$ isolated vertices. 

  15. The History of Collagenase Clostridium Histolyticum.

    Science.gov (United States)

    Yang, Kevin K; Bennett, Nelson

    2015-10-01

    After its U.S. FDA approval in 2013, Collagenase Clostridium histolyticum (CCh) has seen increasing use as a nonoperative treatment for Peyronie's disease (PD). We review the history of CCh and trials that led to its adoption. To provide a historical and contemporary context for the evolution of Collagenase Clostridium histolyticum as a treatment modality for Peyronie's disease. A comprehensive search of peer-reviewed literature was performed pertaining to CCh and its biochemical and clinical significance. The main outcome studied was the efficacy and safety profile of CCh in PD. CCh use in other diseases processes and its associated outcomes are also described. CCh injection yields objective improvement in penile curvature across multiple trials in PD patients. Recently, level 1 strength of evidence has emerged supporting its widespread use. As such, CCh stands as the only FDA-approved injectable therapy for PD. Adverse events were namely limited to local reactions. Serious systemic complications and need for intervention were rare. CCh is a safe and effective treatment for PD patients with deformities and plaque configuration amenable to injectable therapy. Multiple trials have demonstrated improvements in objective and subjective metrics such as penile curvature and bother scores. However, multiyear follow-up is needed to assess durability and its sustained clinical significance. Currently, refinement in dosing and technique has established a niche for CCh in PD patients who are affected by their symptoms but are not yet committed to surgical intervention. Yang KK and Bennett N. The history of collagenase clostridium histolyticum. Copyright © 2015 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

  16. Clostridium Difficile Infection in the Nephrology Ward

    Directory of Open Access Journals (Sweden)

    Sylwia Dudzicz

    2017-11-01

    Full Text Available Clostridium difficile is currently the most frequently identified pathogen causing antibiotic-associated diarrhea and the main cause of nosocomial diarrhea. In recent years, increases incidence of infection, severe infection, recurrent infection and mortality from Clostridium difficile infection (CDI have been observed. This may be a consequence of excessive antibiotic use and spread of the hypervirulent epidemic BI/NAP1/027 strain of Clostridium difficile. The main risk factors for CDI are: antibiotic therapy, previous hospitalizations and number of comorbid conditions. Prevention of CDI mainly is focused in two directions: reducing the exposure of patients to the disease pathogen by intensifying hygiene measures, and reducing the impact of risk factors. A meta-analyses of clinical studies (observational, cohort and case control showed significantly higher risk of CDI and CDI recurrence in patients with chronic kidney disease and increased mortality risk in chronic kidney disease patients with CDI comparing those without CDI. Increased risk of CDI in patients with chronic kidney disease can be caused by: frequent antibiotic therapy associated with numerous infections resulting in intestinal microflora dysfunction, frequent hospitalizations, older age of the patients and an impaired immune system. Among preventative measures against CDI, the use of probiotics were also studied. In patients hospitalized in nephrology ward highly significant reduction of the CDI incidence was observed after the introduction of Lactobacillus plantarum 299v as CDI prophylaxis. Therefore, the use of Lactobacillus plantarum 299v seems to be a promising method of CDI prevention in chronic kidney disease patients hospitalized in nephrology ward.

  17. Probiotics and prevention of Clostridium difficile infection.

    Science.gov (United States)

    Goldstein, E J C; Johnson, S J; Maziade, P-J; Evans, C T; Sniffen, J C; Millette, M; McFarland, L V

    2017-06-01

    The role of probiotics as adjunctive measures in the prevention of Clostridium difficile infection (CDI) has been controversial. However, a growing body of evidence has suggested that they have a role in primary prevention of CDI. Elements of this controversy are reviewed and the proposed mechanisms of action, the value and cost effectiveness of probiotics are addressed with a focus on three agents, Saccharomyces boulardii, Lactobacillus rhamnosus GG and the combination of Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R, Lactobacillus rhamnosus CLR2 (Bio-K+). Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Annotation of the Clostridium Acetobutylicum Genome

    Energy Technology Data Exchange (ETDEWEB)

    Daly, M. J.

    2004-06-09

    The genome sequence of the solvent producing bacterium Clostridium acetobutylicum ATCC824, has been determined by the shotgun approach. The genome consists of a 3.94 Mb chromosome and a 192 kb megaplasmid that contains the majority of genes responsible for solvent production. Comparison of C. acetobutylicum to Bacillus subtilis reveals significant local conservation of gene order, which has not been seen in comparisons of other genomes with similar, or, in some cases, closer, phylogenetic proximity. This conservation allows the prediction of many previously undetected operons in both bacteria.

  19. Clostridium difficile in Humans and Food Animals

    Centers for Disease Control (CDC) Podcasts

    2008-06-30

    Clostridium difficile is an antibiotic-resistant bacterium that causes diarrhea and sometimes serious intestinal illnesses. In recent years, C. difficile infections have been increasing in number and severity, including among some people outside healthcare settings. In this podcast, CDC's Dr. Michael Jhung discusses his recent study that looked at a new, increasingly prevalent strain of C. difficile in people and compared it to a strain historically found in animals to see whether the two might be linked. The study is published in the July 2008 issue of Emerging Infectious Diseases.  Created: 6/30/2008 by Emerging Infectious Diseases.   Date Released: 7/3/2008.

  20. Clostridium difficile in Humans and Food Animals

    Centers for Disease Control (CDC) Podcasts

    Clostridium difficile is an antibiotic-resistant bacterium that causes diarrhea and sometimes serious intestinal illnesses. In recent years, C. difficile infections have been increasing in number and severity, including among some people outside healthcare settings. In this podcast, CDC's Dr. Michael Jhung discusses his recent study that looked at a new, increasingly prevalent strain of C. difficile in people and compared it to a strain historically found in animals to see whether the two might be linked. The study is published in the July 2008 issue of Emerging Infectious Diseases.

  1. Sensitive enumeration of Listeria monocytogenes and other Listeria species in various naturally contaminated matrices using a membrane filtration method.

    Science.gov (United States)

    Barre, Léna; Brasseur, Emilie; Doux, Camille; Lombard, Bertrand; Besse, Nathalie Gnanou

    2015-06-01

    For the enumeration of Listeria monocytogenes (L. monocytogenes) in food, a sensitive enumeration method has been recently developed. This method is based on a membrane filtration of the food suspension followed by transfer of the filter on a selective medium to enumerate L. monocytogenes. An evaluation of this method was performed with several categories of foods naturally contaminated with L. monocytogenes. The results obtained with this technique were compared with those obtained from the modified reference EN ISO 11290-2 method for the enumeration of L. monocytogenes in food, and are found to provide more precise results. In most cases, the filtration method enabled to examine a greater quantity of food thus greatly improving the sensitivity of the enumeration. However, it was hardly applicable to some food categories because of filtration problems and background microbiota interference. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Optimisation of a direct plating method for the detection and enumeration of Alicyclobacillus acidoterrestris spores.

    Science.gov (United States)

    Henczka, Marek; Djas, Małgorzata; Filipek, Katarzyna

    2013-01-01

    A direct plating method for the detection and enumeration of Alicyclobacillus acidoterrestris spores has been optimised. The results of the application of four types of growth media (BAT agar, YSG agar, K agar and SK agar) regarding the recovery and enumeration of A. acidoterrestris spores were compared. The influence of the type of applied growth medium, heat shock conditions, incubation temperature, incubation time, plating technique and the presence of apple juice in the sample on the accuracy of the detection and enumeration of A. acidoterrestris spores was investigated. Among the investigated media, YSG agar was the most sensitive medium, and its application resulted in the highest recovery of A. acidoterrestris spores, while K agar and BAT agar were the least suitable media. The effect of the heat shock time on the recovery of spores was negligible. When there was a low concentration of spores in a sample, the membrane filtration method was superior to the spread plating method. The obtained results show that heat shock carried out at 80°C for 10 min and plating samples in combination with membrane filtration on YSG agar, followed by incubation at 46°C for 3 days provided the optimal conditions for the detection and enumeration of A. acidoterrestris spores. Application of the presented method allows highly efficient, fast and sensitive identification and enumeration of A. acidoterrestris spores in food products. This methodology will be useful for the fruit juice industry for identifying products contaminated with A. acidoterrestris spores, and its practical application may prevent economic losses for manufacturers. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. The effect of New Neonatal Porcine Diarrhoea Syndrome (NNPDS) on average daily gain and mortality in 4 Danish pig herds

    DEFF Research Database (Denmark)

    Kongsted, Hanne; Stege, Helle; Toft, Nils

    2014-01-01

    , which is not caused by enterotoxigenic Escherichia coli (ETEC), Clostridium perfringens (C. perfringens) type A/C, Clostridium difficile (C. difficile), rotavirus A, coronavirus, Cystoisospora suis, Strongyloides ransomi, Giardia spp or Cryptosporidium spp. Results: Piglets were estimated to have...

  4. Mortality and Clostridium difficile infection in an Australian setting.

    Science.gov (United States)

    Mitchell, Brett G; Gardner, Anne; Hiller, Janet E

    2013-10-01

    To quantify the risk of death associated with Clostridium difficile infection, in an Australian tertiary hospital. Two reviews examining Clostridium difficile infection and mortality indicate that Clostridium difficile infection is associated with increased mortality in hospitalized patients. Studies investigating the mortality of Clostridium difficile infection in settings outside of Europe and North America are required, so that the epidemiology of Clostridium difficile infection in these regions can be understood and appropriate prevention strategies made. An observational non-concurrent cohort study design was used. Data from all persons who had (exposed) and a matched sample of persons who did not have Clostridium difficile infection, for the calendar years 2007-2010, were analysed. The risk of dying within 30, 60, 90 and 180 days was compared using the two groups. Kaplan-Meier survival analysis and conditional logistic regression models were applied to the data to examine time to death and mortality risk adjusted for comorbidities using the Charlson Comorbidity Index. One hundred and fifty-eight cases of infection were identified. A statistically significant difference in all-cause mortality was identified between exposed and non-exposed groups at 60 and 180 days. In a conditional regression model, mortality in the exposed group was significantly higher at 180 days. In this Australian study, Clostridium difficile infection was associated with increased mortality. In doing so, it highlights the need for nurses to immediately instigate contact precautions for persons suspected of having Clostridium difficile infection and to facilitate a timely faecal collection for testing. Our findings support ongoing surveillance of Clostridium difficile infection and associated prevention and control activities. © 2013 Blackwell Publishing Ltd.

  5. Genome-Wide Transcriptional Profiling of Clostridium perfringens SM101 during Sporulation Extends the Core of Putative Sporulation Genes and Genes Determining Spore Properties and Germination Characteristics

    NARCIS (Netherlands)

    Xiao, Y.; Hijum, S.A.F.T. van; Abee, T.; Wells-Bennik, M.H.

    2015-01-01

    The formation of bacterial spores is a highly regulated process and the ultimate properties of the spores are determined during sporulation and subsequent maturation. A wide variety of genes that are expressed during sporulation determine spore properties such as resistance to heat and other adverse

  6. Genome-wide transcriptional profiling of Clostridium perfringens SM101 during sporulation extends the core of putative sporulation genes and genes determining spore properties and germination characteristics

    NARCIS (Netherlands)

    Xiao, Y.; Hijum, van S.A.F.T.; Abee, T.; Wells-Bennik, M.H.J.

    2015-01-01

    The formation of bacterial spores is a highly regulated process and the ultimate properties of the spores are determined during sporulation and subsequent maturation. A wide variety of genes that are expressed during sporulation determine spore properties such as resistance to heat and other adverse

  7. Intoxicación alimentaria por clostridium perfringens en el centro penitenciario cocori, cartago, costa rica, del 4 al 5 de septiembre del 2002

    OpenAIRE

    Espinoza, A; Arguedas, H; Asenjo, A

    2004-01-01

    Introducción El 5 de setiembre del 2002 el Centro Penitenciario Cocorí en Cartago, notificó al Sistema de Vigilancia del Ministerio de Salud, la presencia de 133 casos de diarrea. Ante esta situación, las autoridades de salud plantearon la investigación, para identificar los factores asociados a la presencia del brote. Material y métodos Mediante la revisión de los expedientes de los casos atendidos por diarrea en el Centro Penitenciario, se identificaron los que cumplieran con la siguiente d...

  8. Effects of Varium and a pre-cursor formula on cytokine production in broiler chickens challenged with Eimeria maxima and Clostridium perfringens

    Science.gov (United States)

    Two studies were conducted to evaluate the ability of new products with toxin binding properties on cytokine production during a necrotic enteritis challenge. A precursor (PV) formula to the product Varium (V) was tested in experiment one, and PV and V formulas were included in the second experimen...

  9. Investigación de la inactivación de Clostridium perfringens y Enterococcus sp. en aguas mediante procesos convencionales y avanzados de oxidación

    OpenAIRE

    Lanao Maldonado, Munia; Ormad Melero, María Peña

    2012-01-01

    Los contaminantes de tipo biológico deben ser eliminados de las aguas naturales que van a ser utilizadas para el abastecimiento a poblaciones en las estaciones de tratamiento de aguas potables (ETAPs), con el fin de asegurar que cumplen los requisitos mínimos que establece la legislación vigente sobre la calidad del agua de consumo humano (RD 140/2003). Según dicha normativa, un agua es considerada ¿apta para consumo humano¿ si no contiene ningún tipo de microorganismo o sustancia, en una can...

  10. Transport of MS2 phage, Escherichia coli, Clostridium perfringens, Cryptosporidium parvum and Giardia intestinalis in a gravel and a sandy soil : additions and corrections

    NARCIS (Netherlands)

    Hijnen, W.A.M.; Medema, Gerriet Jan; Brouwer-Hanzens, Anke J.; Charles, Katrina J.

    2006-01-01

    To define protection zones around groundwater abstraction wells and safe setback distances for artificial recharge systems in water treatment, quantitative information is needed about the removal of micro-organisms during soil passage. Column experiments were conducted using natural soil and water

  11. Transport of MS2 phage, Escherichia coli, Clostridium perfringens, Cryptosporidium parvum and Giardia intestinalis in a gravel and a sandy soil

    NARCIS (Netherlands)

    Hijnen, W.A.M.; Medema, Gerriet Jan; Brouwer-Hanzens, Anke J.; Charles, Katrina J.

    To define protection zones around groundwater abstraction wells and safe setback distances for artificial recharge systems in water treatment, quantitative information is needed about the removal of micro-organisms during soil passage. Column experiments were conducted using natural soil and water

  12. Influence of different yeast cell wall preparations and their components on performance and immune and metabolic pathways in Clostridium perfringens-challenged broiler chicks

    Science.gov (United States)

    A study was conducted to evaluate the influence of purification of yeast cell wall (YCW) preparations on broiler performance, and immunogenic and metabolic pathways under microbial challenge. A total of 240 day-of-hatch chicks were distributed among two battery brooder units (48 pens; 5 birds/pen; ...

  13. Influence of DOC on the inactivation efficacy of ozonation assessed with Clostridium perfringens and a lab-scale continuous flow system

    NARCIS (Netherlands)

    Hijnen, W.A.M.; Medema, Gerriet Jan; Baars, E.; Bosklopper, T.G.J.; Veer, A.J. van der; Meijers, R.T.

    2004-01-01

    Routine quality monitoring for fecal indicators after ozonation at the river-lake waterworks Weesperkarspel of Amsterdam Water Supply (AWS) show large variation in inactivation. The influence of the high DOC in the water on the inactivation efficiency was investigated. Results showed a higher

  14. The pangenome of the genus Clostridium.

    Science.gov (United States)

    Udaondo, Zulema; Duque, Estrella; Ramos, Juan-Luis

    2017-07-01

    The pangenome for the genus Clostridium sensu stricto, which was obtained using highly curated and annotated genomes from 16 species is presented; some of these cause disease, while others are used for the production of added-value chemicals. Multilocus sequencing analysis revealed that species of this genus group into at least two clades that include non-pathogenic and pathogenic strains, suggesting that pathogenicity is dispersed across the phylogenetic tree. The core genome of the genus includes 546 protein families, which mainly comprise those involved in protein translation and DNA repair. The GS-GOGAT may represent the central pathway for generating organic nitrogen from inorganic nitrogen sources. Glycerol and glucose metabolism genes are well represented in the core genome together with a set of energy conservation systems. A metabolic network comprising proteins/enzymes, RNAs and metabolites, whose topological structure is a non-random and scale-free network with hierarchically structured modules was built. These modules shed light on the interactions between RNAs, proteins and metabolites, revealing biological features of transcription and translation, cell wall biosynthesis, C1 metabolism and N metabolism. Network analysis identified four nodes that function as hubs and bottlenecks, namely, coenzyme A, HPr kinases, S-adenosylmethionine and the ribonuclease P-protein, suggesting pivotal roles for them in Clostridium. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. Secretion of clostridium cellulase by E. coli

    Science.gov (United States)

    Yu, Ida Kuo

    1998-01-01

    A gene, encoding an endocellulase from a newly isolated mesophilic Clostridium strain IY-2 which can digest bamboo fibers, cellulose, rice straw, and sawdust, was isolated by shotgun cloning in an E. coli expression plasmid pLC2833. E. coli positive clones were selected based on their ability to hydrolyze milled bamboo fibers and cellulose present in agar plates. One clone contained a 2.8 kb DNA fragment that was responsible for cellulase activity. Western blot analyses indicated that the positive clone produced a secreted cellulase with a mass of about 58,000 daltons that was identical in size to the subunit of one of the three major Clostridium cellulases. The products of cellulose digestion by this cloned cellulase were cellotetraose and soluble higher polymers. The cloned DNA contained signal sequences capable of directing the secretion of heterologous proteins from an E. coli host. The invention describes a bioprocess for the treatment of cellulosic plant materials to produce cellular growth substrates and fermentation end products suitable for production of liquid fuels, solvents, and acids.

  16. Key Research Issues in Clostridium difficile

    Directory of Open Access Journals (Sweden)

    George Zhanel

    2005-01-01

    Full Text Available Clostridium difficile is an emerging pathogen that causes C difficile-associated diarrhea, an important nosocomial infection. Control of this infection remains a challenge, and much needs to be determined about the antimicrobial resistance of the organism, antibiotic stewardship, contamination of the patient environment, and various host factors that determine susceptibility or resistance to infection. A national symposium focusing on C difficile infections, the Clostridium difficile Symposium on Emerging Issues and Research, was hosted on November 23, 2004, by the Department of Medical Microbiology and Infectious Diseases at the University of Manitoba, Winnipeg, Manitoba, in partnership with the Canadian Institutes of Health Research. This symposium, which aimed to summarize key research issues regarding C difficile infections in Canada, had the following objectives: to provide a forum for learning and discussion about C difficile and its impact on the health of Canadians; to identify the key research issues that should be addressed; and to explore potential research funding opportunities and collaboration. The present report summarizes key research issues identified for C difficile infections in Canada by addressing four major themes: diagnosis and surveillance, infection prevention and control, antibiotic stewardship, and clinical management.

  17. Molecular typing of toxigenic Clostridum perfringens isolated from sheep in Iran

    Directory of Open Access Journals (Sweden)

    Abdolmohammadi Khiav, L.

    2011-12-01

    Full Text Available In this research a molecular method based on polymerase chain reaction for typing of Clostridiumperfringens was developed and toxin genotypes of 64 isolates from sheep and goats in Iran weredetermined. The PCR assays were developed for detection of alpha (cpa, beta (cpb and epsilon (etxtoxin genes, allowing classification of the isolates into genotypes A B, C and D. The field isolates wereassigned to genotypes A (n=9, 14.07 %, B (n=20, 31.25%, C (n=17, 26.56% and D (n=18, 28.12%. Inthis PCR system the fragments of 900, 611 and 402 bp were amplified using specific primers for alpha, beta and epsilon toxins, respectively. The fragments were confirmed by sequencing and blasting in GenBank. The sequence alignment of the fragments showed more than 98% similarity with other related published sequences from other sources. Our results suggest that PCR genotyping is an acceptable tool for in vitro typing of C. perfringens.

  18. New industrial butanol-producing organism, Clostridium amylovorum

    Energy Technology Data Exchange (ETDEWEB)

    Cataldi, M S

    1964-01-01

    A new Clostridium was isolated from starch-containing substances; it ferments corn and potato starch and sugar molasses, giving important yields of butanol and acetone; it is gram-positive, strictly anaerobic and sporulates in plectron form.

  19. Clostridium difficile infection in the community: a zoonotic disease?

    NARCIS (Netherlands)

    Hensgens, M.P.; Keessen, E.C.; Squire, M.M.; Riley, T.V.; Koene, M.G.J.; de Boer, E.; Lipman, L.J.A.; Kuijper, E.J.

    2012-01-01

    Clostridium difficile infections (CDIs) are traditionally seen in elderly and hospitalized patients who have used antibiotic therapy. In the community, CDIs requiring a visit to a general practitioner are increasingly occurring among young and relatively healthy individuals without known

  20. Clostridium difficile infections in the community: a zoonotic disease?

    NARCIS (Netherlands)

    Hensgens, M.P.M.; Keessen, A.M.; Squire, M.M.; Riley, T.V.; Koene, M.G.J.; Boer, de E.; Lipman, L.J.; Kuijper, E.J.

    2012-01-01

    Clostridium difficile infections (CDIs) are traditionally seen in elderly and hospitalized patients who have used antibiotic therapy. In the community, CDIs requiring a visit to a general practitioner are increasingly occurring among young and relatively healthy individuals without known

  1. effluent by bacillus cereus and clostridium butyricum using

    African Journals Online (AJOL)

    user

    Double-chambered MFCs was used for the study and operated ..... The third one is wire electron transfer, which uses ... phase indicates that the Bacillus cereus and Clostridium butyricum ..... Improving Start Up Performance With Carbon Mesh.

  2. Clostridium difficile Infection Worsens the Prognosis of Ulcerative Colitis

    Directory of Open Access Journals (Sweden)

    María E Negrón

    2014-01-01

    Full Text Available BACKGROUND: The impact of Clostridium difficile infections among ulcerative colitis (UC patients is well characterized. However, there is little knowledge regarding the association between C difficile infections and postoperative complications among UC patients.

  3. Development of an enumeration method for arsenic methylating bacteria from mixed culture samples.

    Science.gov (United States)

    Islam, S M Atiqul; Fukushi, Kensuke; Yamamoto, Kazuo

    2005-12-01

    Bacterial methylation of arsenic converts inorganic arsenic into volatile and non-volatile methylated species. It plays an important role in the arsenic cycle in the environment. Despite the potential environmental significance of AsMB, an assessment of their population size and activity remains unknown. This study has now established a protocol for enumeration of AsMB by means of the anaerobic-culture-tube, most probable number (MPN) method. Direct detection of volatile arsenic species is then done by GC-MS. This method is advantageous as it can simultaneously enumerate AsMB and acetate and formate-utilizing methanogens. The incubation time for this method was determined to be 6 weeks, sufficient time for AsMB growth.

  4. Spatial working memory load affects counting but not subitizing in enumeration.

    Science.gov (United States)

    Shimomura, Tomonari; Kumada, Takatsune

    2011-08-01

    The present study investigated whether subitizing reflects capacity limitations associated with two types of working memory tasks. Under a dual-task situation, participants performed an enumeration task in conjunction with either a spatial (Experiment 1) or a nonspatial visual (Experiment 2) working memory task. Experiment 1 showed that spatial working memory load affected the slope of a counting function but did not affect subitizing performance or subitizing range. Experiment 2 showed that nonspatial visual working memory load affected neither enumeration efficiency nor subitizing range. Furthermore, in both spatial and nonspatial memory tasks, neither subitizing efficiency nor subitizing range was affected by amount of imposed memory load. In all the experiments, working memory load failed to influence slope, subitizing range, or overall reaction time. These findings suggest that subitizing is performed without either spatial or nonspatial working memory. A possible mechanism of subitizing with independent capacity of working memory is discussed.

  5. Performance of mycological media in enumerating desiccated food spoilage yeasts: an interlaboratory study.

    Science.gov (United States)

    Beuchat, L R; Frandberg, E; Deak, T; Alzamora, S M; Chen, J; Guerrero, A S; López-Malo, A; Ohlsson, I; Olsen, M; Peinado, J M; Schnurer, J; de Siloniz, M I; Tornai-Lehoczki, J

    2001-10-22

    Dichloran 18% glycerol agar (DG18) was originally formulated to enumerate nonfastidious xerophilic moulds in foods containing rapidly growing Eurotium species. Some laboratories are now using DG18 as a general purpose medium for enumerating yeasts and moulds, although its performance in recovering yeasts from dry foods has not been evaluated. An interlaboratory study compared DG18 with dichloran rose bengal chloramphenicol agar (DRBC), plate count agar supplemented with chloramphenicol (PCAC), tryptone glucose yeast extract chloramphenicol agar (TGYC), acidified potato dextrose agar (APDA), and orange serum agar (OSA) for their suitability to enumerate 14 species of lyophilized yeasts. The coefficient of variation for among-laboratories repeatability within yeast was 1.39% and reproducibility of counts among laboratories was 7.1%. The order of performance of media for recovering yeasts was TGYC > PCAC = OSA > APDA > DRBC > DG 18. A second study was done to determine the combined effects of storage time and temperature on viability of yeasts and suitability of media for recovery. Higher viability was retained at -18 degrees C than at 5 degrees C or 25 degrees C for up to 42 weeks, although the difference in mean counts of yeasts stored at -18 degrees C and 25 degrees C was only 0.78 log10 cfu/ml of rehydrated suspension. TGYC was equal to PCAC and superior to the other four media in recovering yeasts stored at -18 degrees C, 5 degrees C, or 25 degrees C for up to 42 weeks. Results from both the interlaboratory study and the storage study support the use of TGYC for enumerating desiccated yeasts. DG18 is not recommended as a general purpose medium for recovering yeasts from a desiccated condition.

  6. Separating the Classes of Recursively Enumerable Languages Based on Machine Size

    Czech Academy of Sciences Publication Activity Database

    van Leeuwen, J.; Wiedermann, Jiří

    2015-01-01

    Roč. 26, č. 6 (2015), s. 677-695 ISSN 0129-0541 R&D Projects: GA ČR GAP202/10/1333 Grant - others:GA ČR(CZ) GA15-04960S Institutional support: RVO:67985807 Keywords : recursively enumerable languages * RE hierarchy * finite languages * machine size * descriptional complexity * Turing machines with advice Subject RIV: IN - Informatics, Computer Science Impact factor: 0.467, year: 2015

  7. Enumeration of smallest intervention strategies in genome-scale metabolic networks.

    Directory of Open Access Journals (Sweden)

    Axel von Kamp

    2014-01-01

    Full Text Available One ultimate goal of metabolic network modeling is the rational redesign of biochemical networks to optimize the production of certain compounds by cellular systems. Although several constraint-based optimization techniques have been developed for this purpose, methods for systematic enumeration of intervention strategies in genome-scale metabolic networks are still lacking. In principle, Minimal Cut Sets (MCSs; inclusion-minimal combinations of reaction or gene deletions that lead to the fulfilment of a given intervention goal provide an exhaustive enumeration approach. However, their disadvantage is the combinatorial explosion in larger networks and the requirement to compute first the elementary modes (EMs which itself is impractical in genome-scale networks. We present MCSEnumerator, a new method for effective enumeration of the smallest MCSs (with fewest interventions in genome-scale metabolic network models. For this we combine two approaches, namely (i the mapping of MCSs to EMs in a dual network, and (ii a modified algorithm by which shortest EMs can be effectively determined in large networks. In this way, we can identify the smallest MCSs by calculating the shortest EMs in the dual network. Realistic application examples demonstrate that our algorithm is able to list thousands of the most efficient intervention strategies in genome-scale networks for various intervention problems. For instance, for the first time we could enumerate all synthetic lethals in E.coli with combinations of up to 5 reactions. We also applied the new algorithm exemplarily to compute strain designs for growth-coupled synthesis of different products (ethanol, fumarate, serine by E.coli. We found numerous new engineering strategies partially requiring less knockouts and guaranteeing higher product yields (even without the assumption of optimal growth than reported previously. The strength of the presented approach is that smallest intervention strategies can be

  8. Comparison of methods for detection and enumeration of airborne microorganisms collected by liquid impingement.

    OpenAIRE

    Terzieva, S; Donnelly, J; Ulevicius, V; Grinshpun, S A; Willeke, K; Stelma, G N; Brenner, K P

    1996-01-01

    Bacterial agents and cell components can be spread as bioaerosols, producing infections and asthmatic problems. This study compares four methods for the detection and enumeration of aerosolized bacteria collected in an AGI-30 impinger. Changes in the total and viable concentrations of Pseudomonas fluorescens in the collection fluid with respect to time of impingement were determined. Two direct microscopic methods (acridine orange and BacLight) and aerodynamic aerosol-size spectrometry (Aeros...

  9. RatBot: anti-enumeration peer-to-peer botnets

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Guanhua [Los Alamos National Laboratory; Eidenbenz, Stephan [Los Alamos National Laboratory; Chen, Songqing [GEORGE MASON UNIV.

    2010-01-01

    Botnets have emerged as one of the most severe cyber threats in recent years. To obtain high resilience against a single point of failure, the new generation of botnets have adopted the peer-to-peer (P2P) structure. One critical question regarding these P2P botnets is: how big are they indeed? To address this question, researchers have proposed both actively crawling and passively monitoring methods to enumerate existing P2P botnets. In this work, we go further to explore the potential strategies that botnets may have to obfuscate their true sizes. Towards this end, this paper introduces RatBot, a P2P botnet that applies some statistical techniques to defeat existing P2P botnet enumeration methods. The key ideas of RatBot are two-fold: (1) there exist a fraction of bots that are indistinguishable from their fake identities, which are spoofing IP addresses they use to hide themselves; (2) we use a heavy-tailed distribution to generate the number of fake identities for each of these bots so that the sum of observed fake identities converges only slowly and thus has high variation. We use large-scale high-fidelity simulation to quantify the estimation errors under diverse settings, and the results show that a naive enumeration technique can overestimate the sizes of P2P botnets by one order of magnitude. We believe that our work reveals new challenges of accurately estimating the sizes of P2P botnets, and hope that it will raise the awareness of security practitioners with these challenges. We further suggest a few countermeasures that can potentially defeat RatBot's anti-enumeration scheme.

  10. The Enumeration Structure of 爾雅 Ěryǎ's "Semantic Lists"

    Science.gov (United States)

    Teboul (戴明德), Michel

    Modern linguistic enumeration theory is applied to a study of 爾雅 Ěryǎ's Semantic Lists, leading to an in-depth analysis of the work's first three sections without any recourse to the traditional methods of Chinese classical philology. It is hoped that an extension of the same method can lead to a better understanding of the remaining 16 sections.

  11. Clostridium difficile infection in Europe: a hospital-based survey

    DEFF Research Database (Denmark)

    Bauer, Martijn P; Notermans, Daan W; van Benthem, Birgit H B

    2011-01-01

    Little is known about the extent of Clostridium difficile infection in Europe. Our aim was to obtain a more complete overview of C difficile infection in Europe and build capacity for diagnosis and surveillance.......Little is known about the extent of Clostridium difficile infection in Europe. Our aim was to obtain a more complete overview of C difficile infection in Europe and build capacity for diagnosis and surveillance....

  12. Reactive arthritis induced by recurrent Clostridium difficile colitis

    Directory of Open Access Journals (Sweden)

    Allison Marr

    2012-01-01

    Full Text Available Clostridium difficile colitis is a common infection that can be difficult to resolve and may result in recurrent infections. Reactive arthritis is a rare presentation of this disease and its treatment is not well differentiated in the literature. We describe a case of reactive arthritis occurring in a patient with a history of recurrent Clostridium difficile colitis while currently receiving a taper of oral vancomycin. His arthritis symptoms resolved with corticosteroids and continued treatment with anticlostridial antibiotics.

  13. An information theory criteria based blind method for enumerating active users in DS-CDMA system

    Science.gov (United States)

    Samsami Khodadad, Farid; Abed Hodtani, Ghosheh

    2014-11-01

    In this paper, a new and blind algorithm for active user enumeration in asynchronous direct sequence code division multiple access (DS-CDMA) in multipath channel scenario is proposed. The proposed method is based on information theory criteria. There are two main categories of information criteria which are widely used in active user enumeration, Akaike Information Criterion (AIC) and Minimum Description Length (MDL) information theory criteria. The main difference between these two criteria is their penalty functions. Due to this difference, MDL is a consistent enumerator which has better performance in higher signal-to-noise ratios (SNR) but AIC is preferred in lower SNRs. In sequel, we propose a SNR compliance method based on subspace and training genetic algorithm to have the performance of both of them. Moreover, our method uses only a single antenna, in difference to the previous methods which decrease hardware complexity. Simulation results show that the proposed method is capable of estimating the number of active users without any prior knowledge and the efficiency of the method.

  14. Media for the isolation and enumeration of bifidobacteria in dairy products.

    Science.gov (United States)

    Roy, D

    2001-09-28

    Bifidobacteria are commonly used for the production of fermented milks, alone or in combination with other lactic acid bacteria. Bifidobacteria populations in fermented milks should be over 10(6) bifidobacteria/g at the time of consumption of strain added to the product. Hence, rapid and reliable methods are needed to routinely determine the initial inoculum and to estimate the storage time period bifidobacteria remain viable. Plate count methods are still preferable for quality control measurements in dairy products. It is, therefore, necessary to have a medium that selectively promotes the growth of bifidobacteria, whereas other bacteria are suppressed. The present paper is an overview of media and methods including summaries of published comparisons between different selective media. Culture media for bifidobacteria may be divided into basal, elective, differential and selective culture medium. Non-selective media are useful for routine enumeration of bifidobacteria when present in non-fermented milks. Reinforced Clostridial Agar and De Man Rogosa Sharpe (MRS) supplemented with cysteine and agar available commercially are the media of choice for industrial quality control laboratories. Several media for selective or differential isolation have been described for enumeration of bifidobacteria from other lactic acid bacteria. From the large number of selective media available, it can be concluded that there is no standard medium for the detection of bifidobacteria. However, Columbia agar base media supplemented with lithium chloride and sodium propionate and MRS medium supplemented with neomycin, paromomycin, nalidixic acid and lithium chloride can be recommended for selective enumeration of bifidobacteria in dairy products.

  15. Natural product-like virtual libraries: recursive atom-based enumeration.

    Science.gov (United States)

    Yu, Melvin J

    2011-03-28

    A new molecular enumerator is described that allows chemically and architecturally diverse sets of natural product-like and drug-like structures to be generated from a core structure as simple as a single carbon atom or as complex as a polycyclic ring system. Integrated with a rudimentary machine-learning algorithm, the enumerator has the ability to assemble biased virtual libraries enriched in compounds predicted to meet target criteria. The ability to dynamically generate relatively small focused libraries in a recursive manner could reduce the computational time and infrastructure necessary to construct and manage extremely large static libraries. Depending on enumeration conditions, natural product-like structures can be produced with a wide range of heterocyclic and alicyclic ring assemblies. Because natural products represent a proven source of validated structures for identifying and designing new drug candidates, mimicking the structural and topological diversity found in nature with a dynamic set of virtual natural product-like compounds may facilitate the creation of new ideas for novel, biologically relevant lead structures in areas of uncharted chemical space.

  16. Automated Mobile System for Accurate Outdoor Tree Crop Enumeration Using an Uncalibrated Camera

    Directory of Open Access Journals (Sweden)

    Thuy Tuong Nguyen

    2015-07-01

    Full Text Available This paper demonstrates an automated computer vision system for outdoor tree crop enumeration in a seedling nursery. The complete system incorporates both hardware components (including an embedded microcontroller, an odometry encoder, and an uncalibrated digital color camera and software algorithms (including microcontroller algorithms and the proposed algorithm for tree crop enumeration required to obtain robust performance in a natural outdoor environment. The enumeration system uses a three-step image analysis process based upon: (1 an orthographic plant projection method integrating a perspective transform with automatic parameter estimation; (2 a plant counting method based on projection histograms; and (3 a double-counting avoidance method based on a homography transform. Experimental results demonstrate the ability to count large numbers of plants automatically with no human effort. Results show that, for tree seedlings having a height up to 40 cm and a within-row tree spacing of approximately 10 cm, the algorithms successfully estimated the number of plants with an average accuracy of 95.2% for trees within a single image and 98% for counting of the whole plant population in a large sequence of images.

  17. Automated Mobile System for Accurate Outdoor Tree Crop Enumeration Using an Uncalibrated Camera.

    Science.gov (United States)

    Nguyen, Thuy Tuong; Slaughter, David C; Hanson, Bradley D; Barber, Andrew; Freitas, Amy; Robles, Daniel; Whelan, Erin

    2015-07-28

    This paper demonstrates an automated computer vision system for outdoor tree crop enumeration in a seedling nursery. The complete system incorporates both hardware components (including an embedded microcontroller, an odometry encoder, and an uncalibrated digital color camera) and software algorithms (including microcontroller algorithms and the proposed algorithm for tree crop enumeration) required to obtain robust performance in a natural outdoor environment. The enumeration system uses a three-step image analysis process based upon: (1) an orthographic plant projection method integrating a perspective transform with automatic parameter estimation; (2) a plant counting method based on projection histograms; and (3) a double-counting avoidance method based on a homography transform. Experimental results demonstrate the ability to count large numbers of plants automatically with no human effort. Results show that, for tree seedlings having a height up to 40 cm and a within-row tree spacing of approximately 10 cm, the algorithms successfully estimated the number of plants with an average accuracy of 95.2% for trees within a single image and 98% for counting of the whole plant population in a large sequence of images.

  18. Updates on the sporulation process in Clostridium species.

    Science.gov (United States)

    Talukdar, Prabhat K; Olguín-Araneda, Valeria; Alnoman, Maryam; Paredes-Sabja, Daniel; Sarker, Mahfuzur R

    2015-05-01

    Sporulation is an important strategy for certain bacterial species within the phylum Firmicutes to survive longer periods of time in adverse conditions. All spore-forming bacteria have two phases in their life; the vegetative form, where they can maintain all metabolic activities and replicate to increase numbers, and the spore form, where no metabolic activities exist. Although many essential components of sporulation are conserved among the spore-forming bacteria, there are differences in the regulation and the pathways among different genera, even at the species level. While we have gained much information from the most studied spore-forming bacterial genus, Bacillus, we still lack an in-depth understanding of spore formation in the genus Clostridium. Clostridium and Bacillus share the master regulator of sporulation, Spo0A, and its downstream pathways, but there are differences in the activation of the Spo0A pathway. While Bacillus species use a multi-component phosphorylation pathway for phosphorylation of Spo0A, termed phosphorelay, such a phosphorelay system is absent in Clostridium. On the other hand, a number of genes regulated by the different sporulation-specific transcription factors are conserved between different Clostridium and Bacillus species. In this review, we discuss the recent findings on Clostridium sporulation and compare the sporulation mechanism in Clostridium and Bacillus. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  19. Biosynthesis of dipicolinic acid in Clostridium roseum

    Energy Technology Data Exchange (ETDEWEB)

    Prakasan, K. (Paraiba Univ., Joao Pessoa (Brazil)); Sharma, D. (Gobind Ballabh Pant Univ. of Agriculture and Technology, Nainital (India))

    1981-02-01

    Dipicolinic acid (DPA) synthesis was studied in Clostridium roseum by permitting the organism to complete vegetative growth in trypticase medium and trasfering the cells to a non-growth-promoting-medium, supplemented with the appropriate /sup 14/C-labelled precursors to complete sporulation and assaying the incorporation of label into DPA. Glu, asp, ala, ser and acetate were found to be efficient precursors of DPA and each one influenced the incorporation of other into DPA. The data suggest that a C/sub 5/ precursor is being trasformed into a C/sub 4/ intermediate, and a C/sub 2/ precursor into a C/sub 4/ intermediate, before their entry into DPA carbon structure. A C/sub 4/ plus C/sub 3/ condensation is favoured over C/sub 5/ plus C/sub 2/ or other condensation in the DPA biosynthesis.

  20. Biosynthesis of dipicolinic acid in Clostridium roseum

    International Nuclear Information System (INIS)

    Prakasan, K.; Sharma, D.

    1981-01-01

    Dipicolinic acid (DPA) synthesis was studied in Clostridium roseum by permitting the organism to complete vegetative growth in trypticase medium and trasfering the cells to a non-growth-promoting-medium, supplemented with the appropriate 14 C-labelled precursors to complete sporulation and assaying the incorporation of label into DPA. Glu, asp, ala, ser and acetate were found to be efficient precursors of DPA and each one influenced the incorporation of other into DPA. The data suggest that a C 5 precursor is being trasformed into a C 4 intermediate, and a C 2 precursor into a C 4 intermediate, before their entry into DPA carbon structure. A C 4 plus C 3 condensation is favoured over C 5 plus C 2 or other condensation in the DPA biosynthesis. (Author) [pt

  1. Survival of probiotic adjunct cultures in cheese and challenges in their enumeration using selective media.

    Science.gov (United States)

    Oberg, C J; Moyes, L V; Domek, M J; Brothersen, C; McMahon, D J

    2011-05-01

    Various selective media for enumerating probiotic and cheese cultures were screened, with 6 media then used to study survival of probiotic bacteria in full-fat and low-fat Cheddar cheese. Commercial strains of Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus paracasei, or Bifidobacterium lactis were added as probiotic adjuncts. The selective media, designed to promote growth of certain lactic acid bacteria (LAB) over others or to differentiate between LAB, were used to detect individual LAB types during cheese storage. Commercial strains of Lactococcus, Lactobacillus, and Bifidobacterium spp. were initially screened on the 6 selective media along with nonstarter LAB (NSLAB) isolates. The microbial flora of the cheeses was analyzed during 9 mo of storage at 6°C. Many NSLAB were able to grow on media presumed selective for Lactococcus, Bifidobacterium spp., or Lb. acidophilus, which became apparent after 90 d of cheese storage, Between 90 and 120 d of storage, bacterial counts changed on media selective for Bifidobacterium spp., suggesting growth of NSLAB. Appearance of NSLAB on Lb. casei selective media [de man, Rogosa, and Sharpe (MRS)+vancomycin] occurred sooner (30 d) in low-fat cheese than in full-fat control cheeses. Differentiation between NSLAB and Lactococcus was achieved by counting after 18 to 24h when the NSLAB colonies were only pinpoint in size. Growth of NSLAB on the various selective media during aging means that probiotic adjunct cultures added during cheesemaking can only be enumerated with confidence on selective media for up to 3 or 4 mo. After this time, growth of NSLAB obfuscates enumeration of probiotic adjuncts. When adjunct Lb. casei or Lb. paracasei cultures are added during cheesemaking, they appear to remain at high numbers for a long time (9 mo) when counted on MRS+vancomycin medium, but a reasonable probability exists that they have been overtaken by NSLAB, which also grow readily on this medium. Enumeration using multiple

  2. Phylogeny of the ammonia-producing ruminal bacteria Peptostreptococcus anaerobius, Clostridium sticklandii, and Clostridium aminophilum sp. nov

    Science.gov (United States)

    Paster, B. J.; Russell, J. B.; Yang, C. M.; Chow, J. M.; Woese, C. R.; Tanner, R.

    1993-01-01

    In previous studies, gram-positive bacteria which grew rapidly with peptides or an amino acid as the sole energy source were isolated from bovine rumina. Three isolates, strains C, FT (T = type strain), and SR, were considered to be ecologically important since they produced up to 20-fold more ammonia than other ammonia-producing ruminal bacteria. On the basis of phenotypic criteria, the taxonomic position of these new isolates was uncertain. In this study, the 16S rRNA sequences of these isolates and related bacteria were determined to establish the phylogenetic positions of the organisms. The sequences of strains C, FT, and SR and reference strains of Peptostreptococcus anaerobius, Clostridium sticklandii, Clostridium coccoides, Clostridium aminovalericum, Acetomaculum ruminis, Clostridium leptum, Clostridium lituseburense, Clostridium acidiurici, and Clostridium barkeri were determined by using a modified Sanger dideoxy chain termination method. Strain C, a large coccus purported to belong to the genus Peptostreptococcus, was closely related to P. anaerobius, with a level of sequence similarity of 99.6%. Strain SR, a heat-resistant, short, rod-shaped organism, was closely related to C. sticklandii, with a level of sequence similarity of 99.9%. However, strain FT, a heat-resistant, pleomorphic, rod-shaped organism, was only distantly related to some clostridial species and P. anaerobius. On the basis of the sequence data, it was clear that strain FT warranted designation as a separate species. The closest known relative of strain FT was C. coccoides (level of similarity, only 90.6%). Additional strains that are phenotypically similar to strain FT were isolated in this study.(ABSTRACT TRUNCATED AT 250 WORDS).

  3. An insight into the isolation, enumeration and molecular detection of Listeria monocytogenes in food

    Directory of Open Access Journals (Sweden)

    Jodi Woan-Fei Law

    2015-11-01

    Full Text Available Listeria monocytogenes, a foodborne pathogen that can cause listeriosis through the consumption of food contaminated with this pathogen. The ability of L. monocytogenes to survive in extreme conditions and cause food contaminations have become a major concern. Hence, routine microbiological food testing is necessary to prevent food contamination and outbreaks of foodborne illness. This review provides insight into the methods for cultural detection, enumeration and molecular identification of L. monocytogenes in various food samples. There are a number of enrichment and plating media that can be used for the isolation of L. monocytogenes from food samples. Enrichment media such as buffered Listeria Enrichment Broth (BLEB, Fraser broth and University of Vermont Medium (UVM Listeria enrichment broth are recommended by regulatory agencies such as FDA-BAM, USDA-FSIS and ISO. Many plating media are available for the isolation of L. monocytogenes, for instance, PALCAM, Oxford and other chromogenic media. Besides, reference methods like FDA-BAM, ISO 11290 method and USDA-FSIS method are usually applied for the cultural detection or enumeration of L. monocytogenes. MPN technique is applied for the enumeration of L. monocytogenes in the case of low level contamination. Molecular methods including polymerase chain reaction (PCR, multiplex polymerase chain reaction (mPCR, real-time/quantitative polymerase chain reaction (qPCR, nucleic acid sequence-based amplification (NASBA, loop-mediated isothermal amplification (LAMP, DNA microarray and Next Generation Sequencing (NGS technology for the detection and identification of L. monocytogenes are discussed in this review. Overall, molecular methods are rapid, sensitive, specific, time- and labour-saving. In future, there are chances for the development of new techniques for the detection and identification of foodborne with improved features.

  4. Enumeration of virtual libraries of combinatorial modular macrocyclic (bracelet, necklace) architectures and their linear counterparts.

    Science.gov (United States)

    Taniguchi, Masahiko; Du, Hai; Lindsey, Jonathan S

    2013-09-23

    A wide variety of cyclic molecular architectures are built of modular subunits and can be formed combinatorially. The mathematics for enumeration of such objects is well-developed yet lacks key features of importance in chemistry, such as specifying (i) the structures of individual members among a set of isomers, (ii) the distribution (i.e., relative amounts) of products, and (iii) the effect of nonequal ratios of reacting monomers on the product distribution. Here, a software program (Cyclaplex) has been developed to determine the number, identity (including isomers), and relative amounts of linear and cyclic architectures from a given number and ratio of reacting monomers. The program includes both mathematical formulas and generative algorithms for enumeration; the latter go beyond the former to provide desired molecular-relevant information and data-mining features. The program is equipped to enumerate four types of architectures: (i) linear architectures with directionality (macroscopic equivalent = electrical extension cords), (ii) linear architectures without directionality (batons), (iii) cyclic architectures with directionality (necklaces), and (iv) cyclic architectures without directionality (bracelets). The program can be applied to cyclic peptides, cycloveratrylenes, cyclens, calixarenes, cyclodextrins, crown ethers, cucurbiturils, annulenes, expanded meso-substituted porphyrin(ogen)s, and diverse supramolecular (e.g., protein) assemblies. The size of accessible architectures encompasses up to 12 modular subunits derived from 12 reacting monomers or larger architectures (e.g. 13-17 subunits) from fewer types of monomers (e.g. 2-4). A particular application concerns understanding the possible heterogeneity of (natural or biohybrid) photosynthetic light-harvesting oligomers (cyclic, linear) formed from distinct peptide subunits.

  5. An insight into the isolation, enumeration, and molecular detection of Listeria monocytogenes in food

    Science.gov (United States)

    Law, Jodi Woan-Fei; Ab Mutalib, Nurul-Syakima; Chan, Kok-Gan; Lee, Learn-Han

    2015-01-01

    Listeria monocytogenes, a foodborne pathogen that can cause listeriosis through the consumption of food contaminated with this pathogen. The ability of L. monocytogenes to survive in extreme conditions and cause food contaminations have become a major concern. Hence, routine microbiological food testing is necessary to prevent food contamination and outbreaks of foodborne illness. This review provides insight into the methods for cultural detection, enumeration, and molecular identification of L. monocytogenes in various food samples. There are a number of enrichment and plating media that can be used for the isolation of L. monocytogenes from food samples. Enrichment media such as buffered Listeria enrichment broth, Fraser broth, and University of Vermont Medium (UVM) Listeria enrichment broth are recommended by regulatory agencies such as Food and Drug Administration-bacteriological and analytical method (FDA-BAM), US Department of Agriculture-Food and Safety (USDA-FSIS), and International Organization for Standardization (ISO). Many plating media are available for the isolation of L. monocytogenes, for instance, polymyxin acriflavin lithium-chloride ceftazidime aesculin mannitol, Oxford, and other chromogenic media. Besides, reference methods like FDA-BAM, ISO 11290 method, and USDA-FSIS method are usually applied for the cultural detection or enumeration of L. monocytogenes. most probable number technique is applied for the enumeration of L. monocytogenes in the case of low level contamination. Molecular methods including polymerase chain reaction, multiplex polymerase chain reaction, real-time/quantitative polymerase chain reaction, nucleic acid sequence-based amplification, loop-mediated isothermal amplification, DNA microarray, and next generation sequencing technology for the detection and identification of L. monocytogenes are discussed in this review. Overall, molecular methods are rapid, sensitive, specific, time- and labor-saving. In future, there are

  6. Enumeration of an extremely high particle-to-PFU ratio for Varicella-zoster virus.

    Science.gov (United States)

    Carpenter, John E; Henderson, Ernesto P; Grose, Charles

    2009-07-01

    Varicella-zoster virus (VZV) is renowned for its low titers. Yet investigations to explore the low infectivity are hampered by the fact that the VZV particle-to-PFU ratio has never been determined with precision. Herein, we accomplish that task by applying newer imaging technology. More than 300 images were taken of VZV-infected cells on 4 different samples at high magnification. We enumerated the total number of viral particles within 25 cm(2) of the infected monolayer at 415 million. Based on these numbers, the VZV particle:PFU ratio was approximately 40,000:1 for a cell-free inoculum.

  7. Specific dot-immunobinding assay for detection and enumeration of Thiobacillus ferrooxidans

    International Nuclear Information System (INIS)

    Arredondo, R.; Jerez, C.A.

    1989-01-01

    A specific and very sensitive dot-immunobinding assay for the detection and enumeration of the bioleaching microorganism Thiobacillus ferrooxidans was developed. Nitrocellulose spotted with samples was incubated with polyclonal antisera against whole T. ferrooxidans cells and then in 125 I-labeled protein A or 125 I-labeled goat antirabbit immunoglobulin G; incubation was followed by autoradiography. Since a minimum of 10 3 cells per dot could be detected, the method offers the possibility of simultaneous processing of numerous samples in a short time to monitor the levels of T. ferrooxidans in bioleaching operations

  8. Enumeration and stability analysis of simple periodic orbits in β-Fermi Pasta Ulam lattice

    International Nuclear Information System (INIS)

    Sonone, Rupali L.; Jain, Sudhir R.

    2014-01-01

    We study the well-known one-dimensional problem of N particles with a nonlinear interaction. The special case of quadratic and quartic interaction potential among nearest neighbours is the β-Fermi-Pasta-Ulam model. We enumerate and classify the simple periodic orbits for this system and find the stability zones, employing Floquet theory. Such stability analysis is crucial to understand the transition of FPU lattice from recurrences to globally chaotic behavior, energy transport in lower dimensional system, dynamics of optical lattices and also its impact on shape parameter of bio-polymers such as DNA and RNA

  9. Enumeration and stability analysis of simple periodic orbits in β-Fermi Pasta Ulam lattice

    Energy Technology Data Exchange (ETDEWEB)

    Sonone, Rupali L., E-mail: vaidehisonone@gmail.com; Jain, Sudhir R., E-mail: vaidehisonone@gmail.com [Department of Physics, University of Pune, Pune-411007, India and Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai - 400085 (India)

    2014-04-24

    We study the well-known one-dimensional problem of N particles with a nonlinear interaction. The special case of quadratic and quartic interaction potential among nearest neighbours is the β-Fermi-Pasta-Ulam model. We enumerate and classify the simple periodic orbits for this system and find the stability zones, employing Floquet theory. Such stability analysis is crucial to understand the transition of FPU lattice from recurrences to globally chaotic behavior, energy transport in lower dimensional system, dynamics of optical lattices and also its impact on shape parameter of bio-polymers such as DNA and RNA.

  10. Specificity for field enumeration of Escherichia coli in tropical surface waters

    DEFF Research Database (Denmark)

    Jensen, Peter Kjær Mackie; Aalbaek, B; Aslam, R

    2001-01-01

    In remote rural areas in developing countries, bacteriological monitoring often depends on the use of commercial field media. This paper evaluates a commercial field medium used for the enumeration of Escherichia coli in different surface waters under primitive field conditions in rural Pakistan....... In order to verify the field kit, 117 presumptive E. coli isolates have been tested, finding a specificity of only 40%. By excluding some strains based on colony colours, the calculated specificity could be increased to 65%. Thus, it is suggested that prior to use in a tropical environment, the specificity...... of any commercial medium used should be tested with representative tropical isolates, in order to increase the specificity....

  11. The economic burden of Clostridium difficile

    Science.gov (United States)

    McGlone, S. M.; Bailey, R. R.; Zimmer, S. M.; Popovich, M. J.; Tian, Y.; Ufberg, P.; Muder, R. R.; Lee, B. Y.

    2013-01-01

    Although Clostridium difficile (C. difficile) is the leading cause of infectious diarrhoea in hospitalized patients, the economic burden of this major nosocomial pathogen for hospitals, third-party payers and society remains unclear. We developed an economic computer simulation model to determine the costs attributable to healthcare-acquired C. difficile infection (CDI) from the hospital, third-party payer and societal perspectives. Sensitivity analyses explored the effects of varying the cost of hospitalization, C. difficile-attributable length of stay, and the probability of initial and secondary recurrences. The median cost of a case ranged from $9179 to $11 456 from the hospital perspective, $8932 to $11 679 from the third-party payor perspective, and $13 310 to $16 464 from the societal perspective. Most of the costs incurred were accrued during a patient’s primary CDI episode. Hospitals with an incidence of 4.1 CDI cases per 100 000 discharges would incur costs ≥$3.2 million (hospital perspective); an incidence of 10.5 would lead to costs ≥$30.6 million. Our model suggests that the annual US economic burden of CDI would be ≥$496 million (hospital perspective), ≥$547 million (third-party payer perspective) and ≥$796 million (societal perspective). Our results show that C. difficile infection is indeed costly, not only to third-party payers and the hospital, but to society as well. These results are consistent with current literature citing C. difficile as a costly disease. PMID:21668576

  12. Clostridium difficile is an autotrophic bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    Michael Köpke

    Full Text Available During the last decade, Clostridium difficile infection showed a dramatic increase in incidence and virulence in the Northern hemisphere. This incessantly challenging disease is the leading cause of antibiotic-associated and nosocomial infectious diarrhea and became life-threatening especially among elderly people. It is generally assumed that all human bacterial pathogens are heterotrophic organisms, being either saccharolytic or proteolytic. So far, this has not been questioned as colonization of the human gut gives access to an environment, rich in organic nutrients. Here, we present data that C. difficile (both clinical and rumen isolates is also able to grow on CO2+H2 as sole carbon and energy source, thus representing the first identified autotrophic bacterial pathogen. Comparison of several different strains revealed high conservation of genes for autotrophic growth and showed that the ability to use gas mixtures for growth decreases or is lost upon prolonged culturing under heterotrophic conditions. The metabolic flexibility of C. difficile (heterotrophic growth on various substrates as well as autotrophy could allow the organism in the gut to avoid competition by niche differentiation and contribute to its survival when stressed or in unfavorable conditions that cause death to other bacteria. This may be an important trait for the pathogenicity of C. difficile.

  13. Phosphorylation of proteins in Clostridium thermohydrosulfuricum

    International Nuclear Information System (INIS)

    Londesborough, J.

    1986-01-01

    Cell extracts of the thermophile Clostridium thermohydrosulfuricum catalyzed the phosphorylation by (γ- 32 P)ATP of several endogenous proteins with M/sub r/s between 13,000 and 100,000. Serine and tyrosine were the main acceptors. Distinct substrate proteins were found in the soluble (e.g., proteins p66, p63, and p53 of M/sub r/s 66,000, 63,000, and 53,000, respectively) and particulate (p76 and p30) fractions, both of which contained protein kinase and phosphatase activity. The soluble fraction suppressed the phosphorylation of particulate proteins and contained a protein kinase inhibitor. Phosphorylation of p53 was promoted by 10μM fructose 1,6-bisphosphate or glucose 1,6-bisphosphate and suppressed by hexose monophosphates, whereas p30 and p13 were suppressed by 5 μM brain (but not spinach) calmodulin. Polyamines, including the odd polyamines characteristic of thermophiles, modulated the labeling of most of the phosphoproteins. Apart from p66, all the proteins labeled in vitro were also rapidly labeled in intact cells by 32 P/sub i/. Several proteins strongly labeled in vivo were labeled slowly or not at all in vitro

  14. Crystal structure of Clostridium difficile toxin A

    Energy Technology Data Exchange (ETDEWEB)

    Chumbler, Nicole M.; Rutherford, Stacey A.; Zhang, Zhifen; Farrow, Melissa A.; Lisher, John P.; Farquhar, Erik; Giedroc, David P.; Spiller, Benjamin W.; Melnyk, Roman A.; Lacy, D. Borden

    2016-01-11

    Clostridium difficile infection is the leading cause of hospital-acquired diarrhoea and pseudomembranous colitis. Disease is mediated by the actions of two toxins, TcdA and TcdB, which cause the diarrhoea, as well as inflammation and necrosis within the colon. The toxins are large (308 and 270 kDa, respectively), homologous (47% amino acid identity) glucosyltransferases that target small GTPases within the host. The multidomain toxins enter cells by receptor-mediated endocytosis and, upon exposure to the low pH of the endosome, insert into and deliver two enzymatic domains across the membrane. Eukaryotic inositol-hexakisphosphate (InsP6) binds an autoprocessing domain to activate a proteolysis event that releases the N-terminal glucosyltransferase domain into the cytosol. Here, we report the crystal structure of a 1,832-amino-acid fragment of TcdA (TcdA1832), which reveals a requirement for zinc in the mechanism of toxin autoprocessing and an extended delivery domain that serves as a scaffold for the hydrophobic α-helices involved in pH-dependent pore formation. A surface loop of the delivery domain whose sequence is strictly conserved among all large clostridial toxins is shown to be functionally important, and is highlighted for future efforts in the development of vaccines and novel therapeutics.

  15. Clostridium difficile – From Colonization to Infection

    Science.gov (United States)

    Schäffler, Holger; Breitrück, Anne

    2018-01-01

    Clostridium difficile is the most frequent cause of nosocomial antibiotic-associated diarrhea. The incidence of C. difficile infection (CDI) has been rising worldwide with subsequent increases in morbidity, mortality, and health care costs. Asymptomatic colonization with C. difficile is common and a high prevalence has been found in specific cohorts, e.g., hospitalized patients, adults in nursing homes and in infants. However, the risk of infection with C. difficile differs significantly between these cohorts. While CDI is a clear indication for therapy, colonization with C. difficile is not believed to be a direct precursor for CDI and therefore does not require treatment. Antibiotic therapy causes alterations of the intestinal microbial composition, enabling C. difficile colonization and consecutive toxin production leading to disruption of the colonic epithelial cells. Clinical symptoms of CDI range from mild diarrhea to potentially life-threatening conditions like pseudomembranous colitis or toxic megacolon. While antibiotics are still the treatment of choice for CDI, new therapies have emerged in recent years such as antibodies against C. difficile toxin B and fecal microbial transfer (FMT). This specific therapy for CDI underscores the role of the indigenous bacterial composition in the prevention of the disease in healthy individuals and its role in the pathogenesis after alteration by antibiotic treatment. In addition to the pathogenesis of CDI, this review focuses on the colonization of C. difficile in the human gut and factors promoting CDI. PMID:29692762

  16. Emerging monoclonal antibodies against Clostridium difficile infection.

    Science.gov (United States)

    Péchiné, Séverine; Janoir, Claire; Collignon, Anne

    2017-04-01

    Clostridium difficile infections are characterized by a high recurrence rate despite antibiotic treatments and there is an urgent need to develop new treatments such as fecal transplantation and immonotherapy. Besides active immunotherapy with vaccines, passive immunotherapy has shown promise, especially with monoclonal antibodies. Areas covered: Herein, the authors review the different assays performed with monoclonal antibodies against C. difficile toxins and surface proteins to treat or prevent primary or recurrent episodes of C. difficile infection in animal models and in clinical trials as well. Notably, the authors lay emphasis on the phase III clinical trial (MODIFY II), which allowed bezlotoxumab to be approved by the Food and Drug Administration and the European Medicines Agency. They also review new strategies for producing single domain antibodies and nanobodies against C. difficile and new approaches to deliver them in the digestive tract. Expert opinion: Only two human Mabs against TcdA and TcdB have been tested alone or in combination in clinical trials. However, many animal model studies have provided rationale for the use of Mabs and nanobodies in C. difficile infection and pave the way for further clinical investigation.

  17. [Epidemiology of Clostridium difficile infection in Spain].

    Science.gov (United States)

    Asensio, Angel; Monge, Diana

    2012-06-01

    There has been increasing interest in Clostridium difficile infection (CDI) due its association with healthcare and its impact on morbidity and mortality in the elderly. During the last few years there has been a growing increase in the number of published studies on the incidence, changes on the clinical presentation and on the epidemiology, with the description of new risk factors. The frequency of CDI in Spain is not sufficiently characterised. The available data indicates that incidence is within the range of that of surrounding countries but increasing. Furthermore, the high and growing use of broad spectrum antibiotics, both in our hospitals and in the community setting, are factors that favour the increase of the disease. The hyper-virulent ribotype 027 has not spread in our hospitals. We need to know with enhanced validity and accuracy the incidence of CDI, both community and healthcare-associated, the information on outbreaks, the incidence on certain population groups, the characterisation of circulating ribotypes and the impact of the disease in terms of mortality and health costs. We need to implement programs for the improvement of antibiotic therapy in the hospital, as well as in the community. Furthermore, the knowledge and the performance of standard precautions need to be improved, particularly hand hygiene, and the specific measures to limit the transmission of C. difficile among the healthcare institutions. Copyright © 2011 Elsevier España, S.L. All rights reserved.

  18. Antibiotic prescribing policy and Clostridium difficile diarrhoea.

    LENUS (Irish Health Repository)

    O'Connor, K A

    2012-02-03

    BACKGROUND: Broad-spectrum antibiotics, particularly intravenous cephalosporins, are associated with Clostridium difficile diarrhoea. Diarrhoea due to C. difficile is a growing problem in hospitals, especially among elderly patients. AIM: To establish whether changing an antibiotic policy with the aim of reducing the use of injectable cephalosporins leads to a reduction in the incidence of C. difficile diarrhoea in elderly patients. DESIGN: Retrospective analysis. METHODS: A group of patients who were subject to the new antibiotic policy from the period following July 2000, were compared with patients who were admitted prior to July 2000 and were not subject to the new policy. Infections, antibiotic prescriptions and mortality rates were determined from case notes, and C. difficle diarrhoea rates from microbiological data. RESULTS: Intravenous cephalosporin use fell from 210 to 28 defined daily doses (p < 0.001) following the change in antibiotic policy, with a corresponding increase in piperacillin-tazobactam (p < 0.001) and moxifloxacin (p < 0.001) use. The new policy led to a significant reduction in C. difficile diarrhoea cases. The relative risk of developing C. difficile infection with the old policy compared to the new policy was 3.24 (95%CI 1.07-9.84, p = 0.03). DISCUSSION: The antibiotic policy was successfully introduced into an elderly care service. It reduced both intravenous cephalosporin use and C. difficile diarrhoea.

  19. Sepsis due to clostridium septicum: case report

    International Nuclear Information System (INIS)

    Foga, M.M.; McGinn, G.J.; Kroeker, M.A.; Guzman, R.

    2000-01-01

    Clostridium septicum is an unusual anaerobic, gram-positive, gas-producing bacillus, which has been identified as a cause of fulminant rapidly fatal infection in humans. Infection with C. septicum usually occurs in patients with cancer, patients receiving immunosuppressive chemotherapy, or patients with a nonmalignant hematological disorder such as hemolytic uremic syndrome. C. septicum infection most commonly involves the abdomen, and a recent review article has identified 164 cases in the medical literature describing the abdominal findings in this disease. Intracranial manifestation of C. septicum infection are less common and include meningitis, cerebritis, abscess formation and pneumocephalus. There have been only 12 documented cases in the English literature describing central nervous system lesions associated with C. septicum. We present a case report of a 56-year-old man in whom septicemia due to C. septicum developed as a complication of Crohn's disease. To our knowledge, there has never been a previous report of C. septicum sepsis related to underlying Crohn's disease. Our case is also remarkable in that an intracerebral gas collection developed at the site of a mycotic infarct related to C. septicum bacteremia, Intracranial, intraparenchymal gas formation related to anaerobic infection is extremely rare; to our knowledge, this radiological finding related to C. septicum sepsis has been described in only 1 previous case report in the medical literature. We also describe the intra-abdominal manifestations of C. septicum sepsis that occurred in this patient as well as the associated radiographic and pathologic findings. (author)

  20. Promoters and proteins from Clostridium thermocellum and uses thereof

    Science.gov (United States)

    Wu, J. H. David; Newcomb, Michael

    2012-11-13

    The present invention relates to an inducible and a high expression nucleic acid promoter isolated from Clostridium thermocellum. These promoters are useful for directing expression of a protein or polypeptide encoded by a nucleic acid molecule operably associated with the nucleic acid promoters. The present invention also relates to nucleic acid constructs including the C. thermocellum promoters, and expression vectors and hosts containing such nucleic acid constructs. The present invention also relates to protein isolated from Clostridium thermocellum, including a repressor protein. The present invention also provides methods of using the isolated promoters and proteins from Clostridium thermocellum, including methods for directing inducible in vitro and in vivo expression of a protein or polypeptide in a host, and methods of producing ethanol from a cellulosic biomass.

  1. Veal Calves Produce Less Antibodies against C. Perfringens Alpha Toxin Compared to Beef Calves

    Directory of Open Access Journals (Sweden)

    Bonnie R. Valgaeren

    2015-07-01

    Full Text Available Enterotoxaemia is a disease with a high associated mortality rate, affecting beef and veal calves worldwide, caused by C. perfringens alpha toxin and perfringolysin. A longitudinal study was conducted to determine the dynamics of antibodies against these toxins in 528 calves on 4 beef and 15 veal farms. The second study aimed to determine the effect of solid feed intake on the production of antibodies against alpha toxin and perfringolysin. The control group only received milk replacer, whereas in the test group solid feed was provided. Maternal antibodies for alpha toxin were present in 45% of the veal calves and 66% of the beef calves. In beef calves a fluent transition from maternal to active immunity was observed for alpha toxin, whereas almost no veal calves developed active immunity. Perfringolysin antibodies significantly declined both in veal and beef calves. In the second study all calves were seropositive for alpha toxin throughout the experiment and solid feed intake did not alter the dynamics of alpha and perfringolysin antibodies. In conclusion, the present study showed that veal calves on a traditional milk replacer diet had significantly lower alpha toxin antibodies compared to beef calves in the risk period for enterotoxaemia, whereas no differences were noticed for perfringolysin.

  2. Veal Calves Produce Less Antibodies against C. Perfringens Alpha Toxin Compared to Beef Calves

    Science.gov (United States)

    Valgaeren, Bonnie R.; Pardon, Bart; Goossens, Evy; Verherstraeten, Stefanie; Roelandt, Sophie; Timbermont, Leen; Van Der Vekens, Nicky; Stuyvaert, Sabrina; Gille, Linde; Van Driessche, Laura; Haesebrouck, Freddy; Ducatelle, Richard; Van Immerseel, Filip; Deprez, Piet

    2015-01-01

    Enterotoxaemia is a disease with a high associated mortality rate, affecting beef and veal calves worldwide, caused by C. perfringens alpha toxin and perfringolysin. A longitudinal study was conducted to determine the dynamics of antibodies against these toxins in 528 calves on 4 beef and 15 veal farms. The second study aimed to determine the effect of solid feed intake on the production of antibodies against alpha toxin and perfringolysin. The control group only received milk replacer, whereas in the test group solid feed was provided. Maternal antibodies for alpha toxin were present in 45% of the veal calves and 66% of the beef calves. In beef calves a fluent transition from maternal to active immunity was observed for alpha toxin, whereas almost no veal calves developed active immunity. Perfringolysin antibodies significantly declined both in veal and beef calves. In the second study all calves were seropositive for alpha toxin throughout the experiment and solid feed intake did not alter the dynamics of alpha and perfringolysin antibodies. In conclusion, the present study showed that veal calves on a traditional milk replacer diet had significantly lower alpha toxin antibodies compared to beef calves in the risk period for enterotoxaemia, whereas no differences were noticed for perfringolysin. PMID:26184311

  3. Veal Calves Produce Less Antibodies against C. Perfringens Alpha Toxin Compared to Beef Calves.

    Science.gov (United States)

    Valgaeren, Bonnie R; Pardon, Bart; Goossens, Evy; Verherstraeten, Stefanie; Roelandt, Sophie; Timbermont, Leen; Van Der Vekens, Nicky; Stuyvaert, Sabrina; Gille, Linde; Van Driessche, Laura; Haesebrouck, Freddy; Ducatelle, Richard; Van Immerseel, Filip; Deprez, Piet

    2015-07-10

    Enterotoxaemia is a disease with a high associated mortality rate, affecting beef and veal calves worldwide, caused by C. perfringens alpha toxin and perfringolysin. A longitudinal study was conducted to determine the dynamics of antibodies against these toxins in 528 calves on 4 beef and 15 veal farms. The second study aimed to determine the effect of solid feed intake on the production of antibodies against alpha toxin and perfringolysin. The control group only received milk replacer, whereas in the test group solid feed was provided. Maternal antibodies for alpha toxin were present in 45% of the veal calves and 66% of the beef calves. In beef calves a fluent transition from maternal to active immunity was observed for alpha toxin, whereas almost no veal calves developed active immunity. Perfringolysin antibodies significantly declined both in veal and beef calves. In the second study all calves were seropositive for alpha toxin throughout the experiment and solid feed intake did not alter the dynamics of alpha and perfringolysin antibodies. In conclusion, the present study showed that veal calves on a traditional milk replacer diet had significantly lower alpha toxin antibodies compared to beef calves in the risk period for enterotoxaemia, whereas no differences were noticed for perfringolysin.

  4. Comparative analysis of chemical similarity methods for modular natural products with a hypothetical structure enumeration algorithm.

    Science.gov (United States)

    Skinnider, Michael A; Dejong, Chris A; Franczak, Brian C; McNicholas, Paul D; Magarvey, Nathan A

    2017-08-16

    Natural products represent a prominent source of pharmaceutically and industrially important agents. Calculating the chemical similarity of two molecules is a central task in cheminformatics, with applications at multiple stages of the drug discovery pipeline. Quantifying the similarity of natural products is a particularly important problem, as the biological activities of these molecules have been extensively optimized by natural selection. The large and structurally complex scaffolds of natural products distinguish their physical and chemical properties from those of synthetic compounds. However, no analysis of the performance of existing methods for molecular similarity calculation specific to natural products has been reported to date. Here, we present LEMONS, an algorithm for the enumeration of hypothetical modular natural product structures. We leverage this algorithm to conduct a comparative analysis of molecular similarity methods within the unique chemical space occupied by modular natural products using controlled synthetic data, and comprehensively investigate the impact of diverse biosynthetic parameters on similarity search. We additionally investigate a recently described algorithm for natural product retrobiosynthesis and alignment, and find that when rule-based retrobiosynthesis can be applied, this approach outperforms conventional two-dimensional fingerprints, suggesting it may represent a valuable approach for the targeted exploration of natural product chemical space and microbial genome mining. Our open-source algorithm is an extensible method of enumerating hypothetical natural product structures with diverse potential applications in bioinformatics.

  5. Multicentre evaluation of stable reference whole blood for enumeration of lymphocyte subsets by flow cytometry.

    Science.gov (United States)

    Edwards, Cherry; Belgrave, Danielle; Janossy, George; Bradley, Nicholas J; Stebbings, Richard; Gaines-Das, Rose; Thorpe, Robin; Sawle, Alex; Arroz, Maria Jorge; Brando, Bruno; Gratama, Jan Willem; Orfao de Matos, Alberto; Papa, Stephano; Papamichail, Michael; Lenkei, Rodica; Rothe, Gregor; Barnett, David

    2005-06-22

    BACKGROUND: Clinical indications for lymphocyte subset enumeration by flow cytometry include monitoring of disease progression and timing of therapeutic intervention in infection with human immunodeficiency virus. Until recently international standardisation has not been possible due to a lack of suitable stable reference material. METHODS: This study consisted of two trials of a stabilised whole blood preparation. Eleven participants were sent two standard protocols for staining plus gating strategy and asked to report absolute counts for lymphocyte subsets. RESULTS: No significant difference was detected between the two methods when results from the two assays and all partners were pooled. Significant differences in results from the different partners were observed. However, representative mean counts were obtained for geometric means, geometric coefficient of variation, and 95% confidence interval for CD3 910 cells/mul, 9%, and 888 to 933, respectively), CD4 (495 cells/mul, 12%, and 483 to 507), and CD8 (408 cells/mul, 13%, and 393 to 422). CONCLUSION: We have introduced a stabilised blood preparation and a well-characterized biological standard. The availability of this reference material greatly simplifies the validation of new techniques for CD4(+) T-cell enumeration and the expansion of external quality assurance programmes for clinical laboratories, including those that operate in resource-restricted environments. (c) 2005 Wiley-Liss, Inc.

  6. The Rise and Fall of Metronidazole for Clostridium difficile Infection.

    Science.gov (United States)

    Chahine, Elias B

    2018-06-01

    Clostridium difficile is posing urgent health threats. Older studies have shown that metronidazole and vancomycin are equally effective in the treatment of Clostridium difficile infection (CDI). Given its inexpensive cost and low propensity to select antimicrobial resistant organisms, metronidazole became rapidly the drug of choice despite its pharmacokinetic limitations in the treatment of CDI. However, newer studies demonstrated that metronidazole is inferior to vancomycin, prompting clinicians to change their long-standing position on using metronidazole for mild to moderate infections and on reserving vancomycin for severe infections. Moving forward, metronidazole will fall out of favor in the treatment of CDI.

  7. Pleiotropic roles of Clostridium difficile sin locus

    Science.gov (United States)

    Ou, Junjun; Dupuy, Bruno

    2018-01-01

    Clostridium difficile is the primary cause of nosocomial diarrhea and pseudomembranous colitis. It produces dormant spores, which serve as an infectious vehicle responsible for transmission of the disease and persistence of the organism in the environment. In Bacillus subtilis, the sin locus coding SinR (113 aa) and SinI (57 aa) is responsible for sporulation inhibition. In B. subtilis, SinR mainly acts as a repressor of its target genes to control sporulation, biofilm formation, and autolysis. SinI is an inhibitor of SinR, so their interaction determines whether SinR can inhibit its target gene expression. The C. difficile genome carries two sinR homologs in the operon that we named sinR and sinR’, coding for SinR (112 aa) and SinR’ (105 aa), respectively. In this study, we constructed and characterized sin locus mutants in two different C. difficile strains R20291 and JIR8094, to decipher the locus’s role in C. difficile physiology. Transcriptome analysis of the sinRR’ mutants revealed their pleiotropic roles in controlling several pathways including sporulation, toxin production, and motility in C. difficile. Through various genetic and biochemical experiments, we have shown that SinR can regulate transcription of key regulators in these pathways, which includes sigD, spo0A, and codY. We have found that SinR’ acts as an antagonist to SinR by blocking its repressor activity. Using a hamster model, we have also demonstrated that the sin locus is needed for successful C. difficile infection. This study reveals the sin locus as a central link that connects the gene regulatory networks of sporulation, toxin production, and motility; three key pathways that are important for C. difficile pathogenesis. PMID:29529083

  8. CRISPR Diversity and Microevolution in Clostridium difficile.

    Science.gov (United States)

    Andersen, Joakim M; Shoup, Madelyn; Robinson, Cathy; Britton, Robert; Olsen, Katharina E P; Barrangou, Rodolphe

    2016-09-19

    Virulent strains of Clostridium difficile have become a global health problem associated with morbidity and mortality. Traditional typing methods do not provide ideal resolution to track outbreak strains, ascertain genetic diversity between isolates, or monitor the phylogeny of this species on a global basis. Here, we investigate the occurrence and diversity of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated genes (cas) in C. difficile to assess the potential of CRISPR-based phylogeny and high-resolution genotyping. A single Type-IB CRISPR-Cas system was identified in 217 analyzed genomes with cas gene clusters present at conserved chromosomal locations, suggesting vertical evolution of the system, assessing a total of 1,865 CRISPR arrays. The CRISPR arrays, markedly enriched (8.5 arrays/genome) compared with other species, occur both at conserved and variable locations across strains, and thus provide a basis for typing based on locus occurrence and spacer polymorphism. Clustering of strains by array composition correlated with sequence type (ST) analysis. Spacer content and polymorphism within conserved CRISPR arrays revealed phylogenetic relationship across clades and within ST. Spacer polymorphisms of conserved arrays were instrumental for differentiating closely related strains, e.g., ST1/RT027/B1 strains and pathogenicity locus encoding ST3/RT001 strains. CRISPR spacers showed sequence similarity to phage sequences, which is consistent with the native role of CRISPR-Cas as adaptive immune systems in bacteria. Overall, CRISPR-Cas sequences constitute a valuable basis for genotyping of C. difficile isolates, provide insights into the micro-evolutionary events that occur between closely related strains, and reflect the evolutionary trajectory of these genomes. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  9. CRISPR Diversity and Microevolution in Clostridium difficile

    Science.gov (United States)

    Andersen, Joakim M.; Shoup, Madelyn; Robinson, Cathy; Britton, Robert; Olsen, Katharina E.P.; Barrangou, Rodolphe

    2016-01-01

    Abstract Virulent strains of Clostridium difficile have become a global health problem associated with morbidity and mortality. Traditional typing methods do not provide ideal resolution to track outbreak strains, ascertain genetic diversity between isolates, or monitor the phylogeny of this species on a global basis. Here, we investigate the occurrence and diversity of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated genes (cas) in C. difficile to assess the potential of CRISPR-based phylogeny and high-resolution genotyping. A single Type-IB CRISPR-Cas system was identified in 217 analyzed genomes with cas gene clusters present at conserved chromosomal locations, suggesting vertical evolution of the system, assessing a total of 1,865 CRISPR arrays. The CRISPR arrays, markedly enriched (8.5 arrays/genome) compared with other species, occur both at conserved and variable locations across strains, and thus provide a basis for typing based on locus occurrence and spacer polymorphism. Clustering of strains by array composition correlated with sequence type (ST) analysis. Spacer content and polymorphism within conserved CRISPR arrays revealed phylogenetic relationship across clades and within ST. Spacer polymorphisms of conserved arrays were instrumental for differentiating closely related strains, e.g., ST1/RT027/B1 strains and pathogenicity locus encoding ST3/RT001 strains. CRISPR spacers showed sequence similarity to phage sequences, which is consistent with the native role of CRISPR-Cas as adaptive immune systems in bacteria. Overall, CRISPR-Cas sequences constitute a valuable basis for genotyping of C. difficile isolates, provide insights into the micro-evolutionary events that occur between closely related strains, and reflect the evolutionary trajectory of these genomes. PMID:27576538

  10. Clostridium difficile in piglets in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Goldová, Jana; Malinová, A.; Indra, A.; Vítek, L.; Branny, Pavel; Jirásková, Alena

    2012-01-01

    Roč. 57, č. 2 (2012), s. 159-161 ISSN 0015-5632 R&D Projects: GA AV ČR KJB500200901 Institutional research plan: CEZ:AV0Z50200510 Keywords : clostridium * piglets Subject RIV: EE - Microbiology, Virology Impact factor: 0.791, year: 2012

  11. Duodenal infusion of donor feces for recurrent Clostridium difficile

    NARCIS (Netherlands)

    van Nood, Els; Vrieze, Anne; Nieuwdorp, Max; Fuentes, Susana; Zoetendal, Erwin G.; de Vos, Willem M.; Visser, Caroline E.; Kuijper, Ed J.; Bartelsman, Joep F. W. M.; Tijssen, Jan G. P.; Speelman, Peter; Dijkgraaf, Marcel G. W.; Keller, Josbert J.

    2013-01-01

    Recurrent Clostridium difficile infection is difficult to treat, and failure rates for antibiotic therapy are high. We studied the effect of duodenal infusion of donor feces in patients with recurrent C. difficile infection. We randomly assigned patients to receive one of three therapies: an initial

  12. Flooding and Clostridium difficile infection: a case-crossover analysis

    Science.gov (United States)

    Clostridium difficile is a bacterium that can spread by water. It often causes acute gastrointestinal illness in older adults who are hospttalized and/or receiving antibiotics; however, community­ associated infections affecting otherwise healthy individuals have become more comm...

  13. 9 CFR 113.106 - Clostridium Chauvoei Bacterin.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Clostridium Chauvoei Bacterin. 113.106 Section 113.106 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... Animal and Plant Health Inspection Service, shall be used for challenge 14 to 15 days following the last...

  14. 9 CFR 113.107 - Clostridium Haemolyticum Bacterin.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Clostridium Haemolyticum Bacterin. 113.107 Section 113.107 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT... challenge 14 to 15 days following the last injection of the product. Each of eight vaccinates and each of...

  15. Cost-effectiveness in Clostridium difficile treatment decision-making

    NARCIS (Netherlands)

    Nuijten, Mark J. C.; Keller, Josbert J.; Visser, Caroline E.; Redekop, Ken; Claassen, Eric; Speelman, Peter; Pronk, Marja H.

    2015-01-01

    To develop a framework for the clinical and health economic assessment for management of Clostridium difficile infection (CDI). CDI has vast economic consequences emphasizing the need for innovative and cost effective solutions, which were aim of this study. A guidance model was developed for

  16. Imipenem Resistance in Clostridium difficile Ribotype 017, Portugal

    Science.gov (United States)

    Isidro, Joana; Santos, Andrea; Nunes, Alexandra; Borges, Vítor; Silva, Catarina; Vieira, Luís; Mendes, Aristides L.; Serrano, Mónica; Henriques, Adriano O.; Gomes, João Paulo

    2018-01-01

    We describe imipenem-resistant and imipenem-susceptible clinical isolates of Clostridium difficile ribotype 017 in Portugal. All ribotype 017 isolates carried an extra penicillin-binding protein gene, pbp5, and the imipenem-resistant isolates had additional substitutions near the transpeptidase active sites of pbp1 and pbp3. These clones could disseminate and contribute to imipenem resistance. PMID:29553322

  17. Fulminant leukemoid reaction due to postpartum Clostridium sordellii infection

    Directory of Open Access Journals (Sweden)

    Prabhat Agrawal

    2012-01-01

    Full Text Available Clostridium sordellii is gram positive anaerobic spore forming rod and it has been demonstrated to cause gas gangrene, refractory shock, leukemoid reaction, and pleuroperitoneal effusion due to capillary leak. We report here a case of postpartum female who presented with leukemoid reaction, ascites, pleural effusion, and shock without fever 7 days after normal vaginal home delivery.

  18. Investigation of Clostridium botulinum group III's mobilome content

    NARCIS (Netherlands)

    Woudstra, Cédric; Maréchal, Le Caroline; Souillard, Rozenn; Anniballi, Fabrizio; Auricchio, Bruna; Bano, Luca; Bayon-Auboyer, Marie Hélène; Koene, Miriam; Mermoud, Isabelle; Brito, Roseane B.; Lobato, Francisco C.F.; Silva, Rodrigo O.S.; Dorner, Martin B.; Fach, Patrick

    2018-01-01

    Clostridium botulinum group III is mainly responsible for botulism in animals. It could lead to high animal mortality rates and, therefore, represents a major environmental and economic concern. Strains of this group harbor the botulinum toxin locus on an unstable bacteriophage. Since the release of

  19. Clostridium difficile infection in an endemic setting in the Netherlands

    NARCIS (Netherlands)

    Hensgens, M. P. M.; Goorhuis, A.; van Kinschot, C. M. J.; Crobach, M. J. T.; Harmanus, C.; Kuijper, E. J.

    2011-01-01

    The purpose of this investigation was to study risk factors for Clostridium difficile infection (CDI) in an endemic setting. In a 34-month prospective case-control study, we compared the risk factors and clinical characteristics of all consecutively diagnosed hospitalised CDI patients (n = 93) with

  20. The morbidity, mortality, and costs associated with Clostridium difficile infection.

    Science.gov (United States)

    Kwon, Jennie H; Olsen, Margaret A; Dubberke, Erik R

    2015-03-01

    Clostridium difficile infection (CDI) is the most common cause of infectious health care-associated diarrhea and is a major burden to patients and the health care system. The incidence and severity of CDI remain at historically high levels. This article reviews the morbidity, mortality, and costs associated with CDI. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. 112 current trend in antimicrobial susceptibility pattern of clostridium ...

    African Journals Online (AJOL)

    DR. AMINU

    inorganic substances. The odour usually gives a suggestion that Clostridium species was present. C. tetani is an obligate anaerobe, and therefore its isolation requires an environment, which is totally devoid of even a trace of oxygen. The technique applied in this research to create an anaerobic condition was found to be ...

  2. First described case of prosthetic joint infection with Clostridium disporicum.

    Science.gov (United States)

    McBride, Joseph A; Sterkel, Alana K; Rehrauer, William M; Smith, Jeannina A

    2017-12-01

    An orthopedic hardware infection with Clostridium disporicum is described. C. disporicum is a gram positive anaerobic bacillus which can contain two subterminal spores. C. disporicum had not previously been reported in musculoskeletal infections. Gram stains demonstrating gram positive bacilli with two subterminal spores should alert practitioners to the possibility of C. disporicum infection. Published by Elsevier Ltd.

  3. Update of treatment algorithms for Clostridium difficile infection

    NARCIS (Netherlands)

    Ooijevaar, R. E.; van Beurden, Y. H.; Terveer, E. M.; Goorhuis, A.; Bauer, M. P.; Keller, J. J.; Mulder, C. J. J.; Kuijper, E. J.

    2018-01-01

    Clostridium difficile is the leading cause of antibiotic-associated diarrhea, both in healthcare facilities and the community. The recurrence rate of C. difficile infection (CDI) remains high, up to 20%. Since the publication of the ESCMID guidance document on CDI treatment in 2014, new therapeutic

  4. Validation of a Rapid Bacteria Endospore Enumeration System for Planetary Protection Application

    Science.gov (United States)

    Chen, Fei; Kern, Roger; Kazarians, Gayane; Venkateswaran, Kasthuri

    NASA monitors spacecraft surfaces to assure that the presence of bacterial endospores meets strict criteria at launch, to minimize the risk of inadvertent contamination of the surface of Mars. Currently, the only approved method for enumerating the spores is a culture based assay that requires three days to produce results. In order to meet the demanding schedules of spacecraft assembly, a more rapid spore detection assay is being considered as an alternate method to the NASA standard culture-based assay. The Millipore Rapid Microbiology Detection System (RMDS) has been used successfully for rapid bioburden enumeration in the pharmaceutical and food industries. The RMDS is rapid and simple, shows high sensitivity (to 1 colony forming unit [CFU]/sample), and correlates well with traditional culture-based methods. It combines membrane filtration, adenosine triphosphate (ATP) bioluminescence chemistry, and image analysis based on photon detection with a Charge Coupled Device (CCD) camera. In this study, we have optimized the assay conditions and evaluated the use of the RMDS as a rapid spore detection tool for NASA applications. In order to select for spores, the samples were subjected to a heat shock step before proceeding with the RMDS incubation protocol. Seven species of Bacillus (nine strains) that have been repeatedly isolated from clean room environments were assayed. All strains were detected by the RMDS in 5 hours and these assay times were repeatedly demonstrated along with low image background noise. Validation experiments to compare the Rapid Sore Assay (RSA) and NASA standard assay (NSA) were also performed. The evaluation criteria were modeled after the FDA Guideline of Process Validation, and Analytical Test Methods. This body of research demonstrates that the Rapid Spore Assay (RSA) is quick, and of equivalent sensitivity to the NASA standard assay, potentially reducing the assay time for bacterial endospores from over 72 hours to less than 8 hours

  5. Strategies for enumeration of circulating microvesicles on a conventional flow cytometer: Counting beads and scatter parameters.

    Science.gov (United States)

    Alkhatatbeh, Mohammad J; Enjeti, Anoop K; Baqar, Sara; Ekinci, Elif I; Liu, Dorothy; Thorne, Rick F; Lincz, Lisa F

    2018-01-01

    Enumeration of circulating microvesicles (MVs) by conventional flow cytometry is accomplished by the addition of a known amount of counting beads and calculated from the formula: MV/μl = (MV count/bead count) × final bead concentration. We sought to optimize each variable in the equation by determining the best parameters for detecting 'MV count' and examining the effects of different bead preparations and concentrations on the final calculation. Three commercially available bead preparations (TruCount, Flow-Count and CountBright) were tested, and MV detection on a BD FACSCanto was optimized for gating by either forward scatter (FSC) or side scatter (SSC); the results were compared by calculating different subsets of MV on a series of 74 typical patient plasma samples. The relationship between the number of beads added to each test and the number of beads counted by flow cytometry remained linear over a wide range of bead concentrations ( R 2 ≥ 0.997). However, TruCount beads produced the most consistent (concentration variation = 3.8%) calculated numbers of plasma CD41 + /Annexin V + MV, which were significantly higher from that calculated using either Flow-Count or CountBright ( p beads by FSC and 0.16 μm beads by SSC, but there were significantly more background events using SSC compared with FSC (3113 vs. 470; p = 0.008). In general, sample analysis by SSC resulted in significantly higher numbers of MV ( p beads provided linear results at concentrations ranging from 6 beads/μl to 100 beads/μl, but TruCount was the most consistent. Using SSC to gate MV events produced high background which negatively affected counting bead enumeration and overall MV calculations. Strategies to reduce SSC background should be employed in order to reliably use this technique.

  6. Use of enrichment real-time PCR to enumerate salmonella on chicken parts.

    Science.gov (United States)

    Oscar, T P

    2014-07-01

    Salmonella bacteria that survive cooking or that cross-contaminate other food during meal preparation and serving represent primary routes of consumer exposure to this pathogen from chicken. In the present study, enrichment real-time PCR (qPCR) was used to enumerate Salmonella bacteria that contaminate raw chicken parts at retail or that cross-contaminate cooked chicken during simulated meal preparation and serving. Whole raw chickens obtained at retail were partitioned into wings, breasts, thighs, and drumsticks using a sterilized knife and cutting board, which were then used to partition a cooked chicken breast to assess cross-contamination. After enrichment in buffered peptone water (400 ml, 8 h, 40°C, 80 rpm), subsamples were used for qPCR and cultural isolation of Salmonella. In some experiments, chicken parts were spiked with 0 to 3.6 log of Salmonella Typhimurium var. 5- to generate a standard curve for enumeration by qPCR. Of 10 raw chickens examined, 7 (70%) had one or more parts contaminated with Salmonella. Of 80 raw parts examined, 15 (19%) were contaminated with Salmonella. Of 20 cooked chicken parts examined, 2 (10%) were cross-contaminated with Salmonella. Predominant serotypes identified were Typhimurium (71%) and its variants (var. 5-, monophasic, and nonmotile) and Kentucky (18%). The number of Salmonella bacteria on contaminated parts ranged from one to two per part. Results of this study indicated that retail chicken parts examined were contaminated with low levels of Salmonella, which resulted in low levels of cross-contamination during simulated meal preparation and serving. Thus, if consumers properly handle and prepare the chicken, it should pose no or very low risk of consumer exposure to Salmonella.

  7. The Application of Digital Pathology to Improve Accuracy in Glomerular Enumeration in Renal Biopsies.

    Directory of Open Access Journals (Sweden)

    Avi Z Rosenberg

    Full Text Available In renal biopsy reporting, quantitative measurements, such as glomerular number and percentage of globally sclerotic glomeruli, is central to diagnostic accuracy and prognosis. The aim of this study is to determine the number of glomeruli and percent globally sclerotic in renal biopsies by means of registration of serial tissue sections and manual enumeration, compared to the numbers in pathology reports from routine light microscopic assessment.We reviewed 277 biopsies from the Nephrotic Syndrome Study Network (NEPTUNE digital pathology repository, enumerating 9,379 glomeruli by means of whole slide imaging. Glomerular number and the percentage of globally sclerotic glomeruli are values routinely recorded in the official renal biopsy pathology report from the 25 participating centers. Two general trends in reporting were noted: total number per biopsy or average number per level/section. Both of these approaches were assessed for their accuracy in comparison to the analogous numbers of annotated glomeruli on WSI.The number of glomeruli annotated was consistently higher than those reported (p<0.001; this difference was proportional to the number of glomeruli. In contrast, percent globally sclerotic were similar when calculated on total glomeruli, but greater in FSGS when calculated on average number of glomeruli (p<0.01. The difference in percent globally sclerotic between annotated and those recorded in pathology reports was significant when global sclerosis is greater than 40%.Although glass slides were not available for direct comparison to whole slide image annotation, this study indicates that routine manual light microscopy assessment of number of glomeruli is inaccurate, and the magnitude of this error is proportional to the total number of glomeruli.

  8. A selective medium for the enumeration and differentiation of Lactobacillus delbrueckii ssp. bulgaricus.

    Science.gov (United States)

    Nwamaioha, Nwadiuto O; Ibrahim, Salam A

    2018-06-01

    Modified reinforced clostridial medium (mRCM) was developed and evaluated for the differential enumeration of Lactobacillus delbrueckii ssp. bulgaricus. Lactobacillus bulgaricus, an important species of lactic acid bacteria with health benefits, is used in the production of yogurt and other fermented foods. Our results showed that supplementing reinforced clostridial medium with 0.025% CaCl 2 , 0.01% uracil, and 0.2% Tween 80 (mRCM) significantly enhanced the growth rate of L. bulgaricus RR and ATCC 11842 strains as measured by the optical densities of these strains after 12 h of incubation at 42°C. The bacterial populations (plate count) of the RR and ATCC 11842 strains were 0.76 and 0.77 log cfu/g higher in mRCM than in de Man, Rogosa, and Sharpe and reinforced clostridial medium media, respectively. Conversely, the population counts for other bacterial species (Bifidobacterium, Lactobacillus rhamnosus, and Lactobacillus reuteri) were significantly inhibited in the mRCM medium. The addition of aniline blue dye to mRCM (mRCM-blue) improved the selectivity of L. bulgaricus in mixed lactic bacterial cultures compared with de Man, Rogosa, and Sharpe medium and lactic agar with regard to colony appearance and morphology. The mRCM-blue performed better than the conventional medium in culturing, enumerating, and differentiating L. bulgaricus. Therefore, mRCM-blue could be used as a selective medium to enhance the growth and differentiation of L. bulgaricus in order to meet the increasing demand for this beneficial species of bacteria. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  9. Multiplex PCR assay for the simultaneous detection of C. perfringens, P. aeruginosa and K. pneumoniae

    Directory of Open Access Journals (Sweden)

    Pradeepkiran Jangampalli Adi

    2015-11-01

    Results and conclusions: Through this approach, the above pathogens were detected simultaneously with high specificity in pure cultures and from the blood and urine samples. The results were correlated with normal diagnostic process, and proved to be more sensitive and specific diagnostic technique in the simultaneous detection of C. perfringens, P. aeruginosa and K. pneumoniae.

  10. Seven-hour fluorescence in situ hybridization technique for enumeration of Enterobacteriaceae in food and environmental water sample.

    Science.gov (United States)

    Ootsubo, M; Shimizu, T; Tanaka, R; Sawabe, T; Tajima, K; Ezura, Y

    2003-01-01

    A fluorescent in situ hybridization (FISH) technique using an Enterobacteriaceae-specific probe (probe D) to target 16S rRNA was improved in order to enumerate, within a single working day, Enterobacteriaceae present in food and environmental water samples. In order to minimize the time required for the FISH procedure, each step of FISH with probe D was re-evaluated using cultured Escherichia coli. Five minutes of ethanol treatment for cell fixation and hybridization were sufficient to visualize cultured E. coli, and FISH could be performed within 1 h. Because of the difficulties in detecting low levels of bacterial cells by FISH without cultivation, a FISH technique for detecting microcolonies on membrane filters was investigated to improve the bacterial detection limit. FISH with probe D following 6 h of cultivation to grow microcolonies on a 13 mm diameter membrane filter was performed, and whole Enterobacteriaceae microcolonies on the filter were then detected and enumerated by manual epifluorescence microscopic scanning at magnification of x100 in ca 5 min. The total time for FISH with probe D following cultivation (FISHFC) was reduced to within 7 h. FISHFC can be applied to enumerate cultivable Enterobacteriaceae in food (above 100 cells g-1) and environmental water samples (above 1 cell ml-1). Cultivable Enterobacteriaceae in food and water samples were enumerated accurately within 7 h using the FISHFC method. A FISHFC method capable of evaluating Enterobacteriaceae contamination in food and environmental water within a single working day was developed.

  11. Effect of storage time and temperature of equine feces on the subsequent enumeration of lactobacilli and cellulolytic bacteria

    Science.gov (United States)

    Cellulolytic bacteria and lactobacilli are beneficial microbes in the equine hindgut. There are several existing methodologies for the enumeration of these bacteria, which vary based on selective and differential media and sample handling procedures including storage time and temperature. The object...

  12. An interlaboratory study to find an alternative to the MPN technique for enumerating Escherichia coli in shellfish

    DEFF Research Database (Denmark)

    Ogden, I.D.; Brown, G.C.; Gallacher, S.

    1998-01-01

    Nine laboratories in eight countries tested 16 batches of common mussels (Mytilus edulis) over a 32 week period in order to find an alternative to the Most Probable Number (MPN) technique to enumerate E. coli. The alternatives investigated included the 3M Petrifilm system, the Merck Chromocult agar...

  13. Enumeration of sugars and sugar alcohols hydroxyl groups by aqueous-based acetylation and MALDI-TOF mass spectrometry

    Science.gov (United States)

    A method is described for enumerating hydroxyl groups on analytes in aqueous media is described, and applied to some common polyalcohols (erythritol, mannitol, and xylitol) and selected carbohydrates. The analytes were derivatized in water with vinyl acetate in presence of sodium phosphate buffer. ...

  14. Accuracy and impact of spatial aids based upon satellite enumeration to improve indoor residual spraying spatial coverage.

    Science.gov (United States)

    Bridges, Daniel J; Pollard, Derek; Winters, Anna M; Winters, Benjamin; Sikaala, Chadwick; Renn, Silvia; Larsen, David A

    2018-02-23

    Indoor residual spraying (IRS) is a key tool in the fight to control, eliminate and ultimately eradicate malaria. IRS protection is based on a communal effect such that an individual's protection primarily relies on the community-level coverage of IRS with limited protection being provided by household-level coverage. To ensure a communal effect is achieved through IRS, achieving high and uniform community-level coverage should be the ultimate priority of an IRS campaign. Ensuring high community-level coverage of IRS in malaria-endemic areas is challenging given the lack of information available about both the location and number of households needing IRS in any given area. A process termed 'mSpray' has been developed and implemented and involves use of satellite imagery for enumeration for planning IRS and a mobile application to guide IRS implementation. This study assessed (1) the accuracy of the satellite enumeration and (2) how various degrees of spatial aid provided through the mSpray process affected community-level IRS coverage during the 2015 spray campaign in Zambia. A 2-stage sampling process was applied to assess accuracy of satellite enumeration to determine number and location of sprayable structures. Results indicated an overall sensitivity of 94% for satellite enumeration compared to finding structures on the ground. After adjusting for structure size, roof, and wall type, households in Nchelenge District where all types of satellite-based spatial aids (paper-based maps plus use of the mobile mSpray application) were used were more likely to have received IRS than Kasama district where maps used were not based on satellite enumeration. The probability of a household being sprayed in Nchelenge district where tablet-based maps were used, did not differ statistically from that of a household in Samfya District, where detailed paper-based spatial aids based on satellite enumeration were provided. IRS coverage from the 2015 spray season benefited from

  15. The Effect of Enumeration of Self-Relevant Words on Self-Focused Attention and Repetitive Negative Thoughts

    Science.gov (United States)

    Muranaka, Seiji; Sasaki, Jun

    2018-01-01

    Self-focused attention refers to awareness of self-referent, internally generated information. It can be categorized into dysfunctional (i.e., self-rumination) and functional (self-reflection) aspects. According to theory on cognitive resource limitations (e.g., Moreno, 2006), there is a difference in cognitive resource allocation between these two aspects of self-focused attention. We propose a new task, self-relevant word (SRW) enumeration, that can aid in behaviorally identifying individuals’ use of self-rumination and self-reflection. The present study has two purposes: to determine the association between self-focus and SRW enumeration, and to examine the effect of dysfunctional SRW enumeration on repetitive negative thinking. One hundred forty-six undergraduate students participated in this study. They completed a measure of state anxiety twice, before and after imagining a social failure situation. They also completed the SRW enumeration task, Repetitive Thinking Questionnaire, Short Fear of Negative Evaluation Scale, and Rumination-Reflection Questionnaire. A correlational analysis indicated a significant positive correlation between self-reflection and the number of SRWs. Furthermore, individuals high in self-reflection had a tendency to pay more attention to problems than did those high in self-rumination. A significant positive correlation was found between self-rumination and the strength of self-relevance of negative SRWs. Through a path analysis, we found a significant positive effect of the self-relevance of negative SRWs on repetitive negative thinking. Notably, however, the model that excluded self-rumination as an explanatory variable showed a better fit to the data than did the model that included it. In summary, SRW enumeration might enable selective and independent detection of the degree of self-reflection and self-rumination, and therefore should be examined in future research in order to design new behavioral procedures. PMID:29896140

  16. A shared, flexible neural map architecture reflects capacity limits in both visual short-term memory and enumeration.

    Science.gov (United States)

    Knops, André; Piazza, Manuela; Sengupta, Rakesh; Eger, Evelyn; Melcher, David

    2014-07-23

    Human cognition is characterized by severe capacity limits: we can accurately track, enumerate, or hold in mind only a small number of items at a time. It remains debated whether capacity limitations across tasks are determined by a common system. Here we measure brain activation of adult subjects performing either a visual short-term memory (vSTM) task consisting of holding in mind precise information about the orientation and position of a variable number of items, or an enumeration task consisting of assessing the number of items in those sets. We show that task-specific capacity limits (three to four items in enumeration and two to three in vSTM) are neurally reflected in the activity of the posterior parietal cortex (PPC): an identical set of voxels in this region, commonly activated during the two tasks, changed its overall response profile reflecting task-specific capacity limitations. These results, replicated in a second experiment, were further supported by multivariate pattern analysis in which we could decode the number of items presented over a larger range during enumeration than during vSTM. Finally, we simulated our results with a computational model of PPC using a saliency map architecture in which the level of mutual inhibition between nodes gives rise to capacity limitations and reflects the task-dependent precision with which objects need to be encoded (high precision for vSTM, lower precision for enumeration). Together, our work supports the existence of a common, flexible system underlying capacity limits across tasks in PPC that may take the form of a saliency map. Copyright © 2014 the authors 0270-6474/14/349857-10$15.00/0.

  17. The Effect of Enumeration of Self-Relevant Words on Self-Focused Attention and Repetitive Negative Thoughts

    Directory of Open Access Journals (Sweden)

    Seiji Muranaka

    2018-05-01

    Full Text Available Self-focused attention refers to awareness of self-referent, internally generated information. It can be categorized into dysfunctional (i.e., self-rumination and functional (self-reflection aspects. According to theory on cognitive resource limitations (e.g., Moreno, 2006, there is a difference in cognitive resource allocation between these two aspects of self-focused attention. We propose a new task, self-relevant word (SRW enumeration, that can aid in behaviorally identifying individuals’ use of self-rumination and self-reflection. The present study has two purposes: to determine the association between self-focus and SRW enumeration, and to examine the effect of dysfunctional SRW enumeration on repetitive negative thinking. One hundred forty-six undergraduate students participated in this study. They completed a measure of state anxiety twice, before and after imagining a social failure situation. They also completed the SRW enumeration task, Repetitive Thinking Questionnaire, Short Fear of Negative Evaluation Scale, and Rumination-Reflection Questionnaire. A correlational analysis indicated a significant positive correlation between self-reflection and the number of SRWs. Furthermore, individuals high in self-reflection had a tendency to pay more attention to problems than did those high in self-rumination. A significant positive correlation was found between self-rumination and the strength of self-relevance of negative SRWs. Through a path analysis, we found a significant positive effect of the self-relevance of negative SRWs on repetitive negative thinking. Notably, however, the model that excluded self-rumination as an explanatory variable showed a better fit to the data than did the model that included it. In summary, SRW enumeration might enable selective and independent detection of the degree of self-reflection and self-rumination, and therefore should be examined in future research in order to design new behavioral procedures.

  18. FT-IR spectroscopic analysis for studying Clostridium cell response to conversion of enzymatically hydrolyzed hay

    Science.gov (United States)

    Grube, Mara; Gavare, Marita; Nescerecka, Alina; Tihomirova, Kristina; Mezule, Linda; Juhna, Talis

    2013-07-01

    Grass hay is one of assailable cellulose containing non-food agricultural wastes that can be used as a carbohydrate source by microorganisms producing biofuels. In this study three Clostridium strains Clostridium acetobutylicum, Clostridium beijerinckii and Clostridium tetanomorphum, capable of producing acetone, butanol and ethanol (ABE) were adapted to convert enzymatically hydrolyzed hay used as a growth media additive. The results of growth curves, substrate degradation kinetics and FT-IR analyses of bacterial biomass macromolecular composition showed diverse strain-specific cell response to the growth medium composition.

  19. Risk factors for Clostridium difficile infection in HIV-infected patients.

    Science.gov (United States)

    Imlay, Hannah; Kaul, Daniel; Rao, Krishna

    2016-01-01

    Clostridium difficile infection is a healthcare-associated infection resulting in significant morbidity. Although immunosuppression is associated with Clostridium difficile infection acquisition and adverse outcomes, the epidemiology of Clostridium difficile infection in HIV-infected patients has been little studied in the era of antiretroviral therapy. This study identifies the risk factors for acquisition of Clostridium difficile infection in HIV-infected patients. A retrospective, propensity score-matched case-control study design was employed, with patients selected from our institution's outpatient HIV clinic. Clostridium difficile infection cases were defined as having positive stool testing plus an appropriate clinical presentation. The propensity score was generated via multiple logistic regression from year of HIV diagnosis, age at first contact, duration of follow-up, gender, and initial CD4 count. The 46 cases included were matched to a total of 180 controls. Prior antibiotic treatment was a significant predictor of Clostridium difficile infection (odds ratio: 13, 95% confidence interval: 3.49-48.8, p  Clostridium difficile infection in the multivariable model (odds ratio: 15.17, confidence interval: 1.31-175.9, p  = .021). As in the general population, frequent hospitalizations and exposure to antimicrobials are independent predictors of Clostridium difficile infection acquisition in patients with HIV. Additionally, low CD4 count and proton pump inhibitor use are new potentially modifiable variables that can be targeted for prevention of Clostridium difficile infection in future interventional studies.

  20. Beneficial and harmful roles of bacteria from the Clostridium genus.

    Science.gov (United States)

    Samul, Dorota; Worsztynowicz, Paulina; Leja, Katarzyna; Grajek, Włodzimierz

    2013-01-01

    Bacteria of the Clostridium genus are often described only as a biological threat and a foe of mankind. However, many of them have positive properties and thanks to them they may be used in many industry branches (e.g., in solvents and alcohol production, in medicine, and also in esthetic cosmetology). During the last 10 years interest in application of C. botulinum and C. tetani in medicine significantly increased. Currently, the structure and biochemical properties of neurotoxins produced by these bacterial species, as well as possibilities of application of such toxins as botulinum as a therapeutic factor in humans, are being intensely researched. The main aim of this article is to demonstrate that bacteria from Clostridium spp. are not only pathogens and the enemy of humanity but they also have many important beneficial properties which make them usable among many chemical, medical, and cosmetic applications.

  1. Models for the study of Clostridium difficile infection

    Science.gov (United States)

    Best, Emma L.; Freeman, Jane; Wilcox, Mark H.

    2012-01-01

    Models of Clostridium difficile infection (C. difficile) have been used extensively for Clostridium difficile (C. difficile) research. The hamster model of C. difficile infection has been most extensively employed for the study of C. difficile and this has been used in many different areas of research, including the induction of C. difficile, the testing of new treatments, population dynamics and characterization of virulence. Investigations using in vitro models for C. difficile introduced the concept of colonization resistance, evaluated the role of antibiotics in C. difficile development, explored population dynamics and have been useful in the evaluation of C. difficile treatments. Experiments using models have major advantages over clinical studies and have been indispensible in furthering C. difficile research. It is important for future study programs to carefully consider the approach to use and therefore be better placed to inform the design and interpretation of clinical studies. PMID:22555466

  2. Fidaxomicin for the treatment of Clostridium difficile infections.

    Science.gov (United States)

    Whitman, Craig B; Czosnowski, Quinn A

    2012-02-01

    To evaluate the pharmacology, microbiology, safety, and efficacy of fidaxomicin for treatment of Clostridium difficile infections (CDI). Literature was identified through Ovid MEDLINE (1948-December 2011) and International Pharmaceutical Abstracts (1970-December 2011) using the search terms fidaxomicin, OPT-80, PAR-101, OP-118, difimicin, tiacumicin, lipiarmycin, Clostridium difficile, Clostridium difficile infection, Clostridium difficile-associated diarrhea, and cost. Drug monographs were retrieved from manufacturers' Web pages, and the Red Book component of Micromedex was used for cost information. All pertinent Phase 1, 2, and 3 studies published in English were included. Fidaxomicin is a macrocyclic compound bactericidal against C. difficile and inhibits toxin and spore production. It has poor oral absorption with high fecal concentrations. Available Phase 2 and 3 data with fidaxomicin 200 mg orally every 12 hours demonstrate similar effectiveness in treating CDI compared to oral vancomycin. Fidaxomicin was shown to have less frequency of recurrent infections. Adverse effects are uncommon and occur at similar rates as with oral vancomycin. The most frequently reported adverse effects are gastrointestinal, hematologic, and electrolyte disorders. Available data are lacking in several areas, including the efficacy and safety of fidaxomicin compared to established regimens for mild-to-moderate, life-threatening, and recurrent CDIs. The cost of a 10-day course of fidaxomicin is significantly more than that of metronidazole and vancomycin for treatment of mild-to-moderate CDI. Fidaxomicin appears to be an effective and safe alternative to oral vancomycin for treatment of mild-to-moderate and severe CDI. Data on its use compared to guideline-recommended therapies for mild-to-moderate and life-threatening CDI are needed. Further data assessing the cost-effectiveness of fidaxomicin are needed. Currently, it cannot be recommended over vancomycin for treatment of CDI

  3. Evaluation of ethanol productivity from cellulose by Clostridium thermocellum

    Energy Technology Data Exchange (ETDEWEB)

    Kurose, N; Yagyu, J; Miyazaki, T; Uchida, M; Hanai, S; Obayashi, A

    1986-01-01

    Clostridium thermocellum, a thermophilic anaerobe, directly converts cellulose to EtOH. To estimate its EtOH production from cellulose, we used a new method based on material balance by which the efficiencies of the enzymes that convert cellulose to ethanol were calculated. Using this method, the maximum efficiency of ethanol production of two strains of C. thermocellum was estimated to be 0.05, with 0.67 as the theoretical maximum. 3 references.

  4. Clostridium difficile infections in patients with severe burns

    Science.gov (United States)

    2011-01-01

    placards indicating that hand hygiene should involve soap and water. Periodic hand hygiene compliance surveys have indicated relatively consistent...care unit: epidemiology, costs, and colonization pressure. Infect Control Hosp Epidemiol 2007;28:123–30. [6] Marcon AP, Gamba MA, Vianna LA. Nosocomial ...Clostridium difficile infections in patients with severe burns§ Scott J. Crabtree a, Janelle L. Robertson a,b, Kevin K. Chung c, Evan M. Renz b,c

  5. Clostridium difficile-associated diarrhoea in infants and children

    OpenAIRE

    Vuletić Biljana; Ristanović Elizabeta; Marković Slavica; Rašković Zorica; Radlović Vladimir; Igrutinović Zoran

    2017-01-01

    Clostridium difficile (CD) is the most common cause of nosocomial diarrhea in adults with high rates of morbidity and mortality. The epidemiology of CD infection (CDI) has changed in the last few decades associated with increasing severity of the infection rate related to the occurrence of NAP1 hypervirulent strain and the emergence of the disease among ambulatory patients and the wider community. Although little is known about CDI in pediatric patients, CD is surprisingly recognized as an im...

  6. Economic evaluation of interventions designed to reduce Clostridium difficile infection.

    Science.gov (United States)

    Brain, David; Yakob, Laith; Barnett, Adrian; Riley, Thomas; Clements, Archie; Halton, Kate; Graves, Nicholas

    2018-01-01

    Healthcare decision-makers are increasingly expected to balance increasing demand for health services with a finite budget. The role of economic evaluation in healthcare is increasing and this research provides decision-makers with new information about the management of Clostridium difficile infection, from an economic perspective. A model-based economic evaluation was undertaken to identify the most cost-effective healthcare intervention relating to the reduction of Clostridium difficile transmission. Efficacy evidence was synthesised from the literature and was used to inform the effectiveness of both bundled approaches and stand-alone interventions, where appropriate intervention combinations were coupled together. Changes in health outcomes were estimated by combining information about intervention effectiveness and its subsequent impact on quality of life. A bundled approach of improving hand hygiene and environmental cleaning produces the best combination of increased health benefits and cost-savings. It has the highest mean net monetary benefit when compared to all other interventions. This intervention remains the optimal decision under different clinical circumstances, such as when mortality rate and patient length of stay are increased. Bundled interventions offered the best opportunity for health improvements. These findings provide healthcare decision-makers with novel information about the allocation of scarce resources relating to Clostridium difficile. If investments are not made in interventions that clearly yield gains in health outcomes, the allocation and use of scarce healthcare resources is inappropriate and improvements in health outcomes will be forgone.

  7. Economic evaluation of interventions designed to reduce Clostridium difficile infection.

    Directory of Open Access Journals (Sweden)

    David Brain

    Full Text Available Healthcare decision-makers are increasingly expected to balance increasing demand for health services with a finite budget. The role of economic evaluation in healthcare is increasing and this research provides decision-makers with new information about the management of Clostridium difficile infection, from an economic perspective.A model-based economic evaluation was undertaken to identify the most cost-effective healthcare intervention relating to the reduction of Clostridium difficile transmission. Efficacy evidence was synthesised from the literature and was used to inform the effectiveness of both bundled approaches and stand-alone interventions, where appropriate intervention combinations were coupled together. Changes in health outcomes were estimated by combining information about intervention effectiveness and its subsequent impact on quality of life.A bundled approach of improving hand hygiene and environmental cleaning produces the best combination of increased health benefits and cost-savings. It has the highest mean net monetary benefit when compared to all other interventions. This intervention remains the optimal decision under different clinical circumstances, such as when mortality rate and patient length of stay are increased. Bundled interventions offered the best opportunity for health improvements.These findings provide healthcare decision-makers with novel information about the allocation of scarce resources relating to Clostridium difficile. If investments are not made in interventions that clearly yield gains in health outcomes, the allocation and use of scarce healthcare resources is inappropriate and improvements in health outcomes will be forgone.

  8. SEVERE CLOSTRIDIUM DIFFICILE INFECTIONS. A SYSTEMATIC LITERATURE -review-

    Directory of Open Access Journals (Sweden)

    Adriana Elena NICA

    2016-06-01

    Full Text Available Clostridium difficile is a bacterium that has been brought to the attention of the medical community recently, as the number of infections related to it has increased dramatically. This is happening mainly because of the excessive and defective use of antibiotic therapy. The pathology of a Clostridium Difficile infection is very complex, as it ranges from easy symptoms like abdominal pain and diarrhea to severe complications, like toxic megacolon. The management of these infections has become even more difficult, as they are not appearing only in the hospital environment anymore, but also outside of it. The bacterium spreads through poor hands hygiene. Also, we don’t have a clear strategy for overcoming an infection like this, so it gets even more difficult as most of the times the doctors need to rely only on their experience and knowledge to find ways of battling it. We would like to underline the research opportunities that are available in this domain as very few things are known about Clostridium difficile and also the crucial importance of research, as these infections are common and dangerous not only for patients, but for the medical staff and their families too.

  9. Emerging therapies for Clostridium difficile infection – focus on fidaxomicin

    Directory of Open Access Journals (Sweden)

    Chaparro-Rojas F

    2013-06-01

    Full Text Available Fredy Chaparro-Rojas, Kathleen M MullaneDepartment of Medicine, Section of Infectious Diseases, University of Chicago, Chicago, IL, USAAbstract: The epidemiology of Clostridium difficile infections (CDI has evolved during the last decades, with an increase in the reported incidence, severity of cases, and rate of mortality and relapses. These increases have primarily affected some special populations including the elderly, patients requiring concomitant antibiotic therapy, patients with renal failure, and patients with cancer. Until recently, the treatment of CDI was limited to either metronidazole or vancomycin. New therapeutic options have emerged to address the shortcomings of current antibiotic therapy. Fidaxomicin stands out as the first-in-class oral macrocyclic antibiotic with targeted activity against C. difficile and minimal collateral damage on the normal colonic flora. Fidaxomicin has demonstrated performance not inferior to what is considered the “gold standard” available therapy for CDI, vancomycin, in two separate Phase III clinical trials, but with significant advantages, including fewer recurrences and higher rates of sustained clinical cures. Fidaxomicin constitutes an important development in targeted antibiotic therapy for CDI and must be considered as a first-line agent for patients with risk factors known to portend relapse and severe infection.Keywords: fidaxomicin, Clostridium difficile-associated diarrhea, CDAD, Clostridium difficile infection (CDI, vancomycin, metronidazole

  10. Application of a good manufacturing practices checklist and enumeration of total coliform in swine feed mills

    Directory of Open Access Journals (Sweden)

    Debora da Cruz Payao Pellegrini

    2014-02-01

    Full Text Available A cross-sectional study in four swine feed mills aimed to evaluate the correlation between the score of the inspection checklist defined in the Normative Instruction 4 (IN 4/ Brazilian Ministry of Agriculture, Livestock and Food Supply, and the enumeration of total coliforms throughout the manufacturing process. The most of non-conformities was found in the physical structure of the feed mills. Feed mill B showed the lowest number of unconformities while units A and D had the largest number of nonconformities. In 38.53% (489/1269 of the samples the presence of total coliform was detected, however no significant difference in the bacterial counts was observed between sampling sites and feed mills. The logistic regression pointed higher odds ratio (OR for total coliforms isolation at dosing (OR = 9.51, 95% CI: 4.43 to 20.41, grinding (OR = 7.10, 95% CI = 3.27 to 15.40 and residues (OR = 6.21, 95% CI: 3.88 to 9.95 In spite of having the second score in the checklist inspection, feed mill C presented the highest odds for total coliforms isolation (OR= 2,43, IC 95%: 1,68-3,53. The data indicate no association between the score of checklist and the presence of hygienic indicators in feed mills.

  11. Development of quantitative real-time PCR for detection and enumeration of Enterobacteriaceae.

    Science.gov (United States)

    Takahashi, Hajime; Saito, Rumi; Miya, Satoko; Tanaka, Yuichiro; Miyamura, Natsumi; Kuda, Takashi; Kimura, Bon

    2017-04-04

    The family Enterobacteriaceae, members of which are widely distributed in the environment, includes many important human pathogens. In this study, a rapid real-time PCR method targeting rplP, coding for L16 protein, a component of the ribosome large subunit, was developed for enumerating Enterobacteriaceae strains, and its efficiency was evaluated using naturally contaminated food products. The rplP-targeted real-time PCR amplified Enterobacteriaceae species with Ct values of 14.0-22.8, whereas the Ct values for non-Enterobacteriaceae species were >30, indicating the specificity of this method for the Enterobacteriaceae. Using a calibration curve of Ct=-3.025 (log CFU/g)+37.35, which was calculated from individual plots of the cell numbers in different concentrations of 5 Enterobacteriaceae species, the rplP-targeted real-time PCR was applied to 51 food samples. A Enterobacteriaceae species in foods rapidly and accurately, and therefore, it can be used for the microbiological risk analysis of foods. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Elucidating the genotype–phenotype map by automatic enumeration and analysis of the phenotypic repertoire

    Science.gov (United States)

    Lomnitz, Jason G; Savageau, Michael A

    2015-01-01

    Background: The gap between genotype and phenotype is filled by complex biochemical systems most of which are poorly understood. Because these systems are complex, it is widely appreciated that quantitative understanding can only be achieved with the aid of mathematical models. However, formulating models and measuring or estimating their numerous rate constants and binding constants is daunting. Here we present a strategy for automating difficult aspects of the process. Methods: The strategy, based on a system design space methodology, is applied to a class of 16 designs for a synthetic gene oscillator that includes seven designs previously formulated on the basis of experimentally measured and estimated parameters. Results: Our strategy provides four important innovations by automating: (1) enumeration of the repertoire of qualitatively distinct phenotypes for a system; (2) generation of parameter values for any particular phenotype; (3) simultaneous realization of parameter values for several phenotypes to aid visualization of transitions from one phenotype to another, in critical cases from functional to dysfunctional; and (4) identification of ensembles of phenotypes whose expression can be phased to achieve a specific sequence of functions for rationally engineering synthetic constructs. Our strategy, applied to the 16 designs, reproduced previous results and identified two additional designs capable of sustained oscillations that were previously missed. Conclusions: Starting with a system’s relatively fixed aspects, its architectural features, our method enables automated analysis of nonlinear biochemical systems from a global perspective, without first specifying parameter values. The examples presented demonstrate the efficiency and power of this automated strategy. PMID:26998346

  13. Elucidating the genotype-phenotype map by automatic enumeration and analysis of the phenotypic repertoire.

    Science.gov (United States)

    Lomnitz, Jason G; Savageau, Michael A

    The gap between genotype and phenotype is filled by complex biochemical systems most of which are poorly understood. Because these systems are complex, it is widely appreciated that quantitative understanding can only be achieved with the aid of mathematical models. However, formulating models and measuring or estimating their numerous rate constants and binding constants is daunting. Here we present a strategy for automating difficult aspects of the process. The strategy, based on a system design space methodology, is applied to a class of 16 designs for a synthetic gene oscillator that includes seven designs previously formulated on the basis of experimentally measured and estimated parameters. Our strategy provides four important innovations by automating: (1) enumeration of the repertoire of qualitatively distinct phenotypes for a system; (2) generation of parameter values for any particular phenotype; (3) simultaneous realization of parameter values for several phenotypes to aid visualization of transitions from one phenotype to another, in critical cases from functional to dysfunctional; and (4) identification of ensembles of phenotypes whose expression can be phased to achieve a specific sequence of functions for rationally engineering synthetic constructs. Our strategy, applied to the 16 designs, reproduced previous results and identified two additional designs capable of sustained oscillations that were previously missed. Starting with a system's relatively fixed aspects, its architectural features, our method enables automated analysis of nonlinear biochemical systems from a global perspective, without first specifying parameter values. The examples presented demonstrate the efficiency and power of this automated strategy.

  14. Comparison of culture media, simplate, and petrifilm for enumeration of yeasts and molds in food.

    Science.gov (United States)

    Taniwaki, M H; Silva, N; Banhe, A A; Iamanaka, B T

    2001-10-01

    The efficacy of three culture media, dichloran rose bengal chloramphenicol (DRBC), dichloran 18% glycerol agar (DG18), and potato dextrose agar (PDA) supplemented with two antibiotics, were compared with the Simplate and Petrifilm techniques for mold and yeast enumeration. The following foods were analyzed: corn meal, wheat flour, cassava flour, bread crumbs, whole meal, sliced bread, ground peanuts, mozzarella cheese, grated parmesan cheese, cheese rolls, orange juice, pineapple pulp, pineapple cake, and mushroom in conserve. Correlation coefficients of DRBC versus PDA and DG18 for recovering total mold and yeast counts from the composite of 14 foods indicated that the three media were generally equivalent. Correlation coefficients for Petrifilm versus culture media were acceptable, although not as good as between culture media. Correlation coefficients of Simplate versus DRBC, DG18, PDA, and Petrifilm for recovering total yeasts and molds from a composite of 11 foods demonstrated that there was no equivalence between the counts obtained by Simplate and other culture media and Petrifilm, with significant differences observed for the most foods analyzed.

  15. Automatic Slide-Loader Fluorescence Microscope for Discriminative Enumeration of Subseafloor Life

    Directory of Open Access Journals (Sweden)

    Fumio Inagaki

    2010-04-01

    Full Text Available The marine subsurface environment is considered the potentially largest ecosystem on Earth, harboring one-tenth of all living biota (Whitman et al., 1998 and comprising diverse microbial components (Inagaki et al., 2003, 2006; Teske, 2006; Inagaki and Nakagawa, 2008. In deep marine sediments, the discrimination of life is significantly more difficult than in surface sediments and terrestrial soils because buried cells generally have extremely low metabolic activities (D’Hondt et al., 2002, 2004, and a highly consolidated sediment matrix produces auto-fluorescence fromdiatomaceous spicules and other mineral particles (Kallmeyer et al., 2008. The cell abundance in marine subsurface sediments has conventionally been evaluated by acridine orange direct count (AODC; Cragg et al., 1995; Parkes et al., 2000 down to 1613 meters below the seafloor (mbsf (Roussel et al., 2008. Since the cell-derived AOsignals often fade out in a short exposure time, recognizing and counting cells require special training. Hence, such efforts to enumerate AO-stained cells from the subseafloor on photographic images have been difficult, and a verification of counts by other methods has been impossible. In addition, providing mean statistical values from low biomass sedimentary habitats has been complicated byphysical and time limitations, yet these habitats are considered critical for understanding the Earth’s biosphere close to the limits of habitable zones (Hoehler, 2004; D’Hondt et al., 2007.

  16. Differential enumeration of subpopulations in concentrated frozen and lyophilized cultures of Lactobacillus delbrueckii ssp. bulgaricus.

    Science.gov (United States)

    Shao, Yuyu; Wang, Zhaoxia; Bao, Qiuhua; Zhang, Heping

    2017-11-01

    Differential enumeration of subpopulations in concentrated frozen and lyophilized cultures of Lactobacillus delbrueckii ssp. bulgaricus ND02 derived from 2 propagation procedures was determined. The subpopulations consisted of 3 categories (physiological states): viable cells capable of forming colonies on agar plates (VC+), viable cells incapable of forming colonies on agar plates (VC-), widely referred to as viable but nonculturable (VBNC) cells, and nonviable or dead cells (NVC). Counts of VC+ were recorded using a conventional plate count procedure. A fluorescent vital staining procedure that discriminates between viable (VC+ and VC-) and NVC cells was used to determine the number of viable and nonviable cells. Both propagation procedures had 2 variables: in procedure (P)1, the propagation medium was rich in yeast extract (4.0%) and the pH was maintained at 5.7; in P2, the medium was devoid of yeast extract and the pH was maintained at 5.1. The results showed that post-propagation operations-concentration of cells by centrifugation and subsequent freezing or lyophilization of cell concentrate-induced different degrees of transience from VC+ to VC- states in cells derived from P1 and P2. Compared with cells derived from P2, cells from P1 were more labile to stress associated with centrifugation, freezing, and lyophilization, as revealed by differential counting. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  17. Examination of Clostridium difficile Contamination in beef meat distributed in Isfahan using culture and Multiplex-PCR method

    OpenAIRE

    zahra Esfandiari; Mohammad Jalali; Hamid Ezzatpanah; Scott Weese; Mohammad Chamani

    2014-01-01

    Introduction: With regard to increasing of community associated Clostridium difficile infection in recent years, the probable transmission of Clostridium difficile from food to human was supposed. Most of reports on this issue were allocated to examine the prevalence of Clostridium difficile in red meat. The current study aimed at examination of the prevalence of Clostridium difficile in beef meat. Materials and methods: A total of 100 beef meat samples includi...

  18. Evaluation of Correlation between Pretest Probability for Clostridium difficile Infection and Clostridium difficile Enzyme Immunoassay Results.

    Science.gov (United States)

    Kwon, Jennie H; Reske, Kimberly A; Hink, Tiffany; Burnham, C A; Dubberke, Erik R

    2017-02-01

    The objective of this study was to evaluate the clinical characteristics and outcomes of hospitalized patients tested for Clostridium difficile and determine the correlation between pretest probability for C. difficile infection (CDI) and assay results. Patients with testing ordered for C. difficile were enrolled and assigned a high, medium, or low pretest probability of CDI based on clinical evaluation, laboratory, and imaging results. Stool was tested for C. difficile by toxin enzyme immunoassay (EIA) and toxigenic culture (TC). Chi-square analyses and the log rank test were utilized. Among the 111 patients enrolled, stool samples from nine were TC positive and four were EIA positive. Sixty-one (55%) patients had clinically significant diarrhea, 19 (17%) patients did not, and clinically significant diarrhea could not be determined for 31 (28%) patients. Seventy-two (65%) patients were assessed as having a low pretest probability of having CDI, 34 (31%) as having a medium probability, and 5 (5%) as having a high probability. None of the patients with low pretest probabilities had a positive EIA, but four were TC positive. None of the seven patients with a positive TC but a negative index EIA developed CDI within 30 days after the index test or died within 90 days after the index toxin EIA date. Pretest probability for CDI should be considered prior to ordering C. difficile testing and must be taken into account when interpreting test results. CDI is a clinical diagnosis supported by laboratory data, and the detection of toxigenic C. difficile in stool does not necessarily confirm the diagnosis of CDI. Copyright © 2017 American Society for Microbiology.

  19. Sporulation of Clostridium cylindrosporum on a Defined, Low-Manganese Medium

    OpenAIRE

    Sacks, L. E.; Smith, M. R.

    1987-01-01

    Clostridium cylindrosporum HC-1 grew and sporulated well on a defined medium. This is the first demonstration of sporulation of a purinolytic clostridium on a defined medium; manganese levels were below those considered essential for sporulation of most Bacillus species. Sporulation appeared to be initiated before exhaustion of the purine substrate.

  20. Mathematical modeling and growth kinetics of Clostridium sporogenes in cooked beef

    Science.gov (United States)

    Clostridium sporogenes PA 3679 is a common surrogate for proteolytic Clostridium botulinum for thermal process development and validation. However, little information is available concerning the growth kinetics of C. sporogenes in food. Therefore, the objective of this study was to investigate the...

  1. Draft Genome Sequence of Antimicrobial-Producing Clostridium sp. JC272, Isolated from Marine Sediment

    OpenAIRE

    Tushar, L.; Sasi Jyothsna, T. S.; Sasikala, C.; Ramana, C. V.

    2015-01-01

    We announce the draft genome sequence of Clostridium sp. JC272, isolated from a sediment sample collected from marine habitats of Gujarat, India. Clostridium sp. JC272 is an obligate anaerobe and has the ability to produce antimicrobial compounds. The genome sequence indicates the strain?s capability of producing small peptides (microcins), which are potential novel antibiotics.

  2. HEMATOPOIETIC PROGENITOR CELLS AS A PREDICTIVE OF CD34+ ENUMERATION PRIOR TO PERIPHERAL BLOOD STEM CELLS HARVESTING

    Directory of Open Access Journals (Sweden)

    Z. Zulkafli

    2014-09-01

    Full Text Available Background: To date, the CD34+ cell enumeration has relied predominantly on flow cytometry technique. However, flow cytometry is time consuming and operator dependent. The application of the hematopoietic progenitor cells (HPCs channel in Sysmex XE-2100, a fully automated hematology analyzer offers an alternative approach, which is with minimal sample manipulation and less operator dependent. This study evaluates the utility of HPC counts as a predictive of CD34+ enumeration prior to peripheral blood stem cells harvesting. Materials and methods: HPC, CD34+, white blood cell (WBC, reticulocytes (retic, immature platelet fraction (IPF and immature reticulocyte fraction (IRF were determined in 61 samples from 19 patients with hematological malignancies (15 lymphoma and 4 multiple myeloma patients at Hospital Universiti Sains Malaysia (Hospital USM who had received granulocyte-colony stimulating factor (G-CSF and planned for autologous transplantation. Results: CD34+ count showed strong and significant correlation with HPC. The receiver operating characteristics (ROC curve analysis revealed that HPC count > 21.5 x 106 / L can predicts a pre harvest CD34+ count of >20 x 106 / L with sensitivity of 77%, specificity of 64% and area under the curve (AUC of 0.802. Conclusion: We concluded that HPC count can be a useful potential parameter in optimizing timing for CD34+ enumeration prior to leukapheresis.

  3. The use of antibiotics to improve phage detection and enumeration by the double-layer agar technique

    Directory of Open Access Journals (Sweden)

    Ferreira Eugénio C

    2009-07-01

    Full Text Available Abstract Background The Double-Layer Agar (DLA technique is extensively used in phage research to enumerate and identify phages and to isolate mutants and new phages. Many phages form large and well-defined plaques that are easily observed so that they can be enumerated when plated by the DLA technique. However, some give rise to small and turbid plaques that are very difficult to detect and count. To overcome these problems, some authors have suggested the use of dyes to improve the contrast between the plaques and the turbid host lawns. It has been reported that some antibiotics stimulate bacteria to produce phages, resulting in an increase in final titer. Thus, antibiotics might contribute to increasing plaque size in solid media. Results Antibiotics with different mechanisms of action were tested for their ability to enhance plaque morphology without suppressing phage development. Some antibiotics increased the phage plaque surface by up to 50-fold. Conclusion This work presents a modification of the DLA technique that can be used routinely in the laboratory, leading to a more accurate enumeration of phages that would be difficult or even impossible otherwise.

  4. Coupling graph perturbation theory with scalable parallel algorithms for large-scale enumeration of maximal cliques in biological graphs

    International Nuclear Information System (INIS)

    Samatova, N F; Schmidt, M C; Hendrix, W; Breimyer, P; Thomas, K; Park, B-H

    2008-01-01

    Data-driven construction of predictive models for biological systems faces challenges from data intensity, uncertainty, and computational complexity. Data-driven model inference is often considered a combinatorial graph problem where an enumeration of all feasible models is sought. The data-intensive and the NP-hard nature of such problems, however, challenges existing methods to meet the required scale of data size and uncertainty, even on modern supercomputers. Maximal clique enumeration (MCE) in a graph derived from such biological data is often a rate-limiting step in detecting protein complexes in protein interaction data, finding clusters of co-expressed genes in microarray data, or identifying clusters of orthologous genes in protein sequence data. We report two key advances that address this challenge. We designed and implemented the first (to the best of our knowledge) parallel MCE algorithm that scales linearly on thousands of processors running MCE on real-world biological networks with thousands and hundreds of thousands of vertices. In addition, we proposed and developed the Graph Perturbation Theory (GPT) that establishes a foundation for efficiently solving the MCE problem in perturbed graphs, which model the uncertainty in the data. GPT formulates necessary and sufficient conditions for detecting the differences between the sets of maximal cliques in the original and perturbed graphs and reduces the enumeration time by more than 80% compared to complete recomputation

  5. Expansion and Compression of Time Correlate with Information Processing in an Enumeration Task.

    Directory of Open Access Journals (Sweden)

    Andreas Wutz

    Full Text Available Perception of temporal duration is subjective and is influenced by factors such as attention and context. For example, unexpected or emotional events are often experienced as if time subjectively expands, suggesting that the amount of information processed in a unit of time can be increased. Time dilation effects have been measured with an oddball paradigm in which an infrequent stimulus is perceived to last longer than standard stimuli in the rest of the sequence. Likewise, time compression for the oddball occurs when the duration of the standard items is relatively brief. Here, we investigated whether the amount of information processing changes when time is perceived as distorted. On each trial, an oddball stimulus of varying numerosity (1-14 items and duration was presented along with standard items that were either short (70 ms or long (1050 ms. Observers were instructed to count the number of dots within the oddball stimulus and to judge its relative duration with respect to the standards on that trial. Consistent with previous results, oddballs were reliably perceived as temporally distorted: expanded for longer standard stimuli blocks and compressed for shorter standards. The occurrence of these distortions of time perception correlated with perceptual processing; i.e. enumeration accuracy increased when time was perceived as expanded and decreased with temporal compression. These results suggest that subjective time distortions are not epiphenomenal, but reflect real changes in sensory processing. Such short-term plasticity in information processing rate could be evolutionarily advantageous in optimizing perception and action during critical moments.

  6. Rapid enumeration of low numbers of moulds in tea based drinks using an automated system.

    Science.gov (United States)

    Tanaka, Kouichi; Yamaguchi, Nobuyasu; Baba, Takashi; Amano, Norihide; Nasu, Masao

    2011-01-31

    Aseptically prepared cold drinks based on tea have become popular worldwide. Contamination of these drinks with harmful microbes is a potential health problem because such drinks are kept free from preservatives to maximize aroma and flavour. Heat-tolerant conidia and ascospores of fungi can survive pasteurization, and need to be detected as quickly as possible. We were able to rapidly and accurately detect low numbers of conidia and ascospores in tea-based drinks using fluorescent staining followed by an automated counting system. Conidia or ascospores were inoculated into green tea and oolong tea, and samples were immediately filtered through nitrocellulose membranes (pore size: 0.8 μm) to concentrate fungal propagules. These were transferred onto potato dextrose agar and incubated for 23 h at 28 °C. Fungi germinating on the membranes were fluorescently stained for 30 min. The stained mycelia were counted selectively within 90s using an automated counting system (MGS-10LD; Chuo Electric Works, Osaka, Japan). Very low numbers (1 CFU/100ml) of conidia or ascospores could be rapidly counted, in contrast to traditional labour intensive techniques. All tested mould strains were detected within 24h while conventional plate counting required 72 h for colony enumeration. Counts of slow-growing fungi (Cladosporium cladosporioides) obtained by automated counting and by conventional plate counting were close (r(2) = 0.986). Our combination of methods enables counting of both fast- and slow-growing fungi, and should be useful for microbiological quality control of tea-based and also other drinks. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Yersinia enterocolitica in slaughter pig tonsils: enumeration and detection by enrichment versus direct plating culture.

    Science.gov (United States)

    Van Damme, Inge; Habib, Ihab; De Zutter, Lieven

    2010-02-01

    Tonsil samples from 139 slaughter pigs were examined for the presence of pathogenic Yersinia enterocolitica by enrichment procedures based on the standard method ISO 10273:2003. In addition, samples were tested by direct plating method to evaluate its efficiency compared to the enrichment culture methods and to quantify the level of contamination in porcine tonsils. In total, 52 samples (37.4%) were positive for pathogenic Y. enterocolitica, all belonging to bioserotype 4/O:3. Fifty out of the 52 positive samples (96.2%) were detected by direct plating. Enumeration showed an average concentration of 4.5 log(10) CFU g(-1) and 4.4 log(10) CFU g(-1) tonsil on Salmonella-Shigella-desoxycholate-calcium chloride (SSDC) and cefsulodin-irgasan-novobiocin (CIN) agar plates, respectively. The enrichment procedures recommended by the ISO 10273:2003 method were not optimal for the isolation of pathogenic Y. enterocolitica from pig tonsils: two days enrichment in irgasan-ticarcillin-potassium chlorate (ITC) broth resulted in an isolation rate of 84.6%, while 5 days enrichment in peptone-sorbitol-bile (PSB) broth recovered only 59.6% of positive samples. Reducing the enrichment time in PSB from 5 to 2 days resulted in a significantly higher recovery rate (94.2%) and might serve as an appropriate enrichment protocol for the isolation of pathogenic Y. enterocolitica from pig tonsils. Compared to enrichment culture methods, results based on direct plating can be obtained in a shorter time course and provide quantitative data that might be needed for further risk assessment studies.

  8. Comparison of New and Traditional Culture-Dependent Media for Enumerating Foodborne Yeasts and Molds.

    Science.gov (United States)

    Beuchat, Larry R; Mann, David A

    2016-01-01

    Fifty-six foods and food ingredients were analyzed for populations of naturally occurring yeasts and molds using Petrifilm rapid yeast and mold (RYM) count plates, Petrifilm yeast and mold (YM) count plates, dichloran rose bengal chloramphenicol (DRBC) agar plates, acidified potato dextrose agar (APDA) plates, and dichloran 18% glycerol (DG18) agar plates. Colonies were counted after incubating plates for 48, 72, and 120 h at 25°C. Of 56 foods in which either yeasts or molds were detected on at least one medium incubated for 120 h, neither yeasts nor molds were detected in 55.4, 73.2, 21.4, 19.6, and 71.4% of foods plated on the five respective media and incubated for 48 h; 10.7, 14.3, 3.6, 1.8, and 19.6% of foods were negative after 72 h, and 3.6, 1.8, 0, 0, and 0% of foods were negative after 120 h. Considering all enumeration media, correlation coefficients were 0.03 to 0.97 at 48 h of incubation; these values increased to 0.75 to 0.99 at 120 h. Coefficients of variation for total yeasts and molds were as high as 30.0, 30.8, and 27.2% at 48, 72, and 120 h, respectively. The general order of performance was DRBC = APDA > RYM Petrifilm > YM Petrifilm ≥ DG18 when plates were incubated for 48 h, DRBC > APDA > RYM Petrifilm > YM Petrifilm ≥ DG18 when plates were incubated for 72 h, and DRBC > APDA > RYM Petrifilm > YM Petrifilm > DG18 when plates were incubated for 120 h. Differences in performance among media are attributed to the diversity of yeasts and molds likely to be present in test foods and differences in nutrient, pH, and water activity requirements for resuscitation of stressed cells and colony development.

  9. An improved procedure for detection and enumeration of walrus signatures in airborne thermal imagery

    Science.gov (United States)

    Burn, Douglas M.; Udevitz, Mark S.; Speckman, Suzann G.; Benter, R. Bradley

    2009-01-01

    In recent years, application of remote sensing to marine mammal surveys has been a promising area of investigation for wildlife managers and researchers. In April 2006, the United States and Russia conducted an aerial survey of Pacific walrus (Odobenus rosmarus divergens) using thermal infrared sensors to detect groups of animals resting on pack ice in the Bering Sea. The goal of this survey was to estimate the size of the Pacific walrus population. An initial analysis of the U.S. data using previously-established methods resulted in lower detectability of walrus groups in the imagery and higher variability in calibration models than was expected based on pilot studies. This paper describes an improved procedure for detection and enumeration of walrus groups in airborne thermal imagery. Thermal images were first subdivided into smaller 200 x 200 pixel "tiles." We calculated three statistics to represent characteristics of walrus signatures from the temperature histogram for each the. Tiles that exhibited one or more of these characteristics were examined further to determine if walrus signatures were present. We used cluster analysis on tiles that contained walrus signatures to determine which pixels belonged to each group. We then calculated a thermal index value for each walrus group in the imagery and used generalized linear models to estimate detection functions (the probability of a group having a positive index value) and calibration functions (the size of a group as a function of its index value) based on counts from matched digital aerial photographs. The new method described here improved our ability to detect walrus groups at both 2 m and 4 m spatial resolution. In addition, the resulting calibration models have lower variance than the original method. We anticipate that the use of this new procedure will greatly improve the quality of the population estimate derived from these data. This procedure may also have broader applicability to thermal infrared

  10. Analyzing the behavior and reliability of voting systems comprising tri-state units using enumerated simulation

    International Nuclear Information System (INIS)

    Yacoub, Sherif

    2003-01-01

    Voting is a common technique used in combining results from peer experts, for multiple purposes, and in a variety of domains. In distributed decision making systems, voting mechanisms are used to obtain a decision by incorporating the opinion of multiple units. Voting systems have many applications in fault tolerant systems, mutual exclusion in distributed systems, and replicated databases. We are specifically interested in voting systems as used in decision-making applications. In this paper, we describe a synthetic experimental procedure to study the behavior of a variety of voting system configurations using a simulator to: analyze the state of each expert, apply a voting mechanism, and analyze the voting results. We introduce an enumerated-simulation approach and compare it to existing mathematical approaches. The paper studies the following behaviors of a voting system: (1) the reliability of the voting system, R; (2) the probability of reaching a consensus, P c ; (3) certainty index, T; and (4) the confidence index, C. The configuration parameters controlling the analysis are: (1) the number of participating experts, N, (2) the possible output states of an expert, and (3) the probability distribution of each expert states. We illustrate the application of this approach to a voting system that consists of N units, each has three states: correct (success), wrong (failed), and abstain (did not produce an output). The final output of the decision-making (voting) system is correct if a consensus is reached on a correct unit output, abstain if all units abstain from voting, and wrong otherwise. We will show that using the proposed approach, we can easily conduct studies to unleash several behaviors of a decision-making system with tri-state experts

  11. Monitor and Protect Wigwam River Bull Trout for Koocanusa Reservoir : Summary of the Skookumchuck Creek Bull Trout Enumeration Project Final Report 2000-2002.

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Jeremy; Baxter, James S.

    2002-12-01

    This report summarizes the third and final year of a bull trout (Salvelinus confluentus) enumeration project on Skookumchuck Creek in southeastern British Columbia. The fence and traps were operated from September 6th to October 11th 2002 in order to enumerate post-spawning bull trout. During the study period a total of 309 bull trout were captured at the fence. In total, 16 fish of undetermined sex, 114 males and 179 females were processed at the fence. Length and weight data, as well as recapture information, were collected for these fish. An additional 41 bull trout were enumerated upstream of the fence by snorkeling prior to fence removal. Coupled with the fence count, the total bull trout enumerated during the project was 350 individuals. Several fish that were tagged in the lower Bull River were recaptured in 2002, as were repeat and alternate year spawners previously enumerated in past years at the fence. A total of 149 bull trout redds were enumerated on the ground in 2002, of which 143 were in the 3.0 km index section (river km 27.5-30.5) that has been surveyed over the past six years. The results of the three year project are summarized, and population characteristics are discussed.

  12. Clostridium septicum aortitis with synchronous ascending colon and rectal adenocarcinoma.

    Science.gov (United States)

    Jain, Deepanshu; Kistler, Andrew C; Kozuch, Patricia

    2017-01-01

    Clostridium septicum ( C. septicum ) aortitis is a rare condition frequently associated with colon adenocarcinoma and carries a poor prognosis. We report the case of a 66-year-old man who presented with abdominal pain, blood in the stool, fever and chills. Laboratory tests were significant for leukocytosis and microcytic anemia. Abdominal imaging revealed a right colon mass and aortitis. Colonoscopy confirmed the right colon mass and also discovered a rectal mass, both adenocarcinomas. Treatment consisted of antibiotics, aortic repair, right hemi-colectomy and later trans-anal excision of the rectal mass. Blood cultures and the aortic specimen grew C. septicum . The patient improved and was doing well in follow up.

  13. Probiotics for the treatment of Clostridium difficile associated disease

    OpenAIRE

    Fitzpatrick, Leo R

    2013-01-01

    The purpose of this review paper is to update the current and potential future role of probiotics for Clostridium difficile-associated disease (CDAD). Included in this review, is an update on the testing of newer probiotics (e.g., Bacillus coagulans GBI-30, 6086) in animal models of CDAD. There is a focus on the modulation of signal transduction pathways (i.e., transcription factors like cAMP response element-binding, activator protein 1, and nuclear factor kappa B), as well as the inhibition...

  14. Probiotics and Antibiotic-Associated Diarrhea and Clostridium difficile Infection

    Science.gov (United States)

    Surawicz, Christina M.

    Diarrhea is a common side effect of antibiotics. Antibiotics can cause diarrhea in 5-25% of individuals who take them but its occurrence is unpredictable. Diarrhea due to antibiotics is called antibiotic-associated diarrhea (AAD). Diarrhea may be mild and resolve when antibiotics are discontinued, or it may be more severe. The most severe form of AAD is caused by overgrowth of Clostridium difficile which can cause severe diarrhea, colitis, pseudomembranous colitis, or even fatal toxic megacolon. Rates of diarrhea vary with the specific antibiotic as well as with the individual susceptibility.

  15. Chitinolytic enzymes from Clostridium paraputrificum for biomedical applications

    Czech Academy of Sciences Publication Activity Database

    Kolenko, Petr; Dušková, Jarmila; Tiščenko, Galina; Koval, Tomáš; Fejfarová, Karla; Šimůnek, Jiří; Hašek, Jindřich; Dohnálek, Jan

    2014-01-01

    Roč. 281, Supplement s1 (2014), s. 653 ISSN 1742-464X. [FEBS EMBO 2014 Conference. 30.08.2014-04.09.2014, Paris] R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk LG14009; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 ; RVO:86652036 ; RVO:67985904 Keywords : chitin * chitinase * clostridium Subject RIV: CE - Biochemistry; EB - Genetics ; Molecular Biology (BTO-N); EE - Microbiology, Virology (UZFG-Y) http://onlinelibrary.wiley.com/doi/10.1111/febs.12919/abstract

  16. Pseudomembranous Colitis: Not Always Caused by Clostridium difficile

    Directory of Open Access Journals (Sweden)

    Derek M. Tang

    2014-01-01

    Full Text Available Although classically pseudomembranous colitis is caused by Clostridium difficile, it can result from several etiologies. Certain medications, chemical injury, collagenous colitis, inflammatory bowel disease, ischemia, and other infectious pathogens can reportedly cause mucosal injury and subsequent pseudomembrane formation. We present the case of a middle-aged woman with vascular disease who was incorrectly diagnosed with refractory C. difficile infection due to the presence of pseudomembranes. Further imaging, endoscopy, and careful histopathology review revealed chronic ischemia as the cause of her pseudomembranous colitis and diarrhea. This case highlights the need for gastroenterologists to consider non-C. difficile etiologies when diagnosing pseudomembranous colitis.

  17. Clostridium difficile-ribotype 027 er en udfordring

    DEFF Research Database (Denmark)

    Nyboe Sommer, Trine; Ravn, Pernille; Gjørup, Ida

    2014-01-01

    Infection with Clostridium difficile is the primary infective cause of antibiotic-associated diarrhoea. In 2008, a major outbreak of CD027 took place in North Zealand, Denmark. We described this infection in a single medical department. Patients positive for C. difficile enlisted at Medical...... Department O, Herlev Hospital, in 2009 were included and demographic data were recorded. In total, 69 patients were included, average age 83 years, Charlson Comorbidity Score 4. Of all patients 24 died. Further studies are needed in order to treat and minimize infection with C. difficile....

  18. Controversies Surrounding Clostridium difficile Infection in Infants and Young Children

    Directory of Open Access Journals (Sweden)

    Maribeth R. Nicholson

    2014-06-01

    Full Text Available Clostridium difficile is a frequent cause of antibiotic-associated diarrhea in adults and older children. However, as many as 80% of infants can be asymptomatically colonized. The reasons for this have not been well established but are believed to be due to differences in toxin receptors or toxin internalization. Determining which children who test positive for C. difficile warrant treatment is exceedingly difficult, especially in the setting of increased rates of detection and the rising risk of disease in children lacking classic risk factors for C. difficile.

  19. Molecular diversity of neurotoxins from Clostridium botulinum type D strains.

    OpenAIRE

    Moriishi, K; Syuto, B; Kubo, S; Oguma, K

    1989-01-01

    The molecular properties of Clostridium botulinum type D South African (D-SA) were compared with those of neurotoxins from type D strain 1873 (D-1873) and type C strains Stockholm and 6813. D-SA toxin, purified 610-fold from the culture supernatant in an overall yield of 30%, consisted of an intact peptide chain with a molecular weight of 140,000. Limited proteolysis of the toxin by trypsin formed a dichain structure consisting of a light chain (Mr, 50,000) and a heavy chain (Mr, 90,000) link...

  20. Quantification of gut lesions in a subclinical necrotic enteritis model

    DEFF Research Database (Denmark)

    Gholamiandehkordi, Ahmad R.; Timbermont, Leen; Lanckriet, Anouk

    2007-01-01

    Currently Clostridium perfringens-induced necrotic enteritis is a major problem in broiler flocks. In the present study, broilers were inoculated with a combination of Eimeria maxima or overdose coccidial vaccine (one inoculation) with C. perfringens (repeated inoculations). Single C. perfringens...... in combination with multiple oral C. perfringens inoculations is a suitable model for necrotic enteritis without inducing mortality of the animals. C. perfringens and Eimeria act synergistically in inducing grossly visible gut damage....