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Sample records for bds bacterial detection

  1. El Test BDS: Posibles Limitaciones

    Directory of Open Access Journals (Sweden)

    Sanz Carnero, Basilio

    2001-01-01

    Full Text Available El test BDS (1987 ha alcanzado un nivel de uso tan elevado que ha sido primeramente publicado en 1996, y, finalmente, elevado a formar parte de uno de los test que incorpora el difundido paquete informático conocido como E-views, en particular, en el caso de la última versión (Versión 4.0. Anticipándonos a lo que esto puede suponer, pretendemos asentar con la mayor claridad y simplicidad posible, los cometidos fundamentales del test BDS. En primer lugar, pretendemos en esta nota mostrar sus fundamentos, y sus limitaciones. Apuntamos, igualmente, algún atractor no detectado por el test, así como el uso sistemático y detallado del proceso a seguir para ejecutar el test. A lo largo del trabajo se exponen algunos criterios de elección de los parámetros principales. Las conclusiones fundamentales son, por un lado, que no es un test de caos determinista, y por otro, que es un test con poder para detectar estructura no lineal, tanto determinista como estocástica. Finalmente, se dan los resultados de aplicar el test original a varios atractores caóticos suficientemente conocidos.

  2. Sensitive, Rapid Detection of Bacterial Spores

    Science.gov (United States)

    Kern, Roger G.; Venkateswaran, Kasthuri; Chen, Fei; Pickett, Molly; Matsuyama, Asahi

    2009-01-01

    A method of sensitive detection of bacterial spores within delays of no more than a few hours has been developed to provide an alternative to a prior three-day NASA standard culture-based assay. A capability for relatively rapid detection of bacterial spores would be beneficial for many endeavors, a few examples being agriculture, medicine, public health, defense against biowarfare, water supply, sanitation, hygiene, and the food-packaging and medical-equipment industries. The method involves the use of a commercial rapid microbial detection system (RMDS) that utilizes a combination of membrane filtration, adenosine triphosphate (ATP) bioluminescence chemistry, and analysis of luminescence images detected by a charge-coupled-device camera. This RMDS has been demonstrated to be highly sensitive in enumerating microbes (it can detect as little as one colony-forming unit per sample) and has been found to yield data in excellent correlation with those of culture-based methods. What makes the present method necessary is that the specific RMDS and the original protocols for its use are not designed for discriminating between bacterial spores and other microbes. In this method, a heat-shock procedure is added prior to an incubation procedure that is specified in the original RMDS protocols. In this heat-shock procedure (which was also described in a prior NASA Tech Briefs article on enumerating sporeforming bacteria), a sample is exposed to a temperature of 80 C for 15 minutes. Spores can survive the heat shock, but nonspore- forming bacteria and spore-forming bacteria that are not in spore form cannot survive. Therefore, any colonies that grow during incubation after the heat shock are deemed to have originated as spores.

  3. Measurement of B(Ds -> munu)

    CERN Document Server

    Abe, K; Aihara, H; Arinstein, K; Aso, T; Aulchenko, V; Aushev, T; Aziz, T; Bahinipati, S; Bakich, A M; Balagura, V; Ban, Y; Banerjee, S; Barberio, E; Bay, A; Bedny, I; Belous, K S; Bhardwaj, V; Bitenc, U; Blyth, S; Bondar, A; Bozek, A; Bracko, M; Brodzicka, J; Browder, T E; Chang, M C; Chang, P; Chao, Y; Chen, A; Chen, K F; Chen, W T; Cheon, B G; Chiang, C C; Chistov, R; Cho, I S; Choi, S K; Choi, Y; Choi, Y K; Cole, S; Dalseno, J; Danilov, M; Das, A; Dash, M; Dragic, J; Drutskoy, A; Eidelman, S; Epifanov, D; Fratina, S; Fujii, H; Fujikawa, M; Gabyshev, N; Garmash, A; Go, A; Gokhroo, G; Goldenzweig, P; Golob, B; Grosse-Perdekamp, M; Guler, H; Ha, H; Haba, J; Hara, K; Hara, T; Hasegawa, Y; Hastings, N C; Hayasaka, K; Hayashii, H; Hazumi, M; Heffernan, D; Higuchi, T; Hinz, L; Hoedlmoser, H; Hokuue, T; Horii, Y; Hoshi, Y; Hoshina, K; Hou, S; Hou, W S; Hsiung, Y B; Hyun, H J; Igarashi, Y; Iijima, T; Ikado, K; Inami, K; Ishikawa, A; Ishino, H; Itoh, R; Iwabuchi, M; Iwasaki, M; Iwasaki, Y; Jacoby, C; Joshi, N J; Kaga, M; Kah, D H; Kaji, H; Kajiwara, S; Kakuno, H; Kang, J H; Kapusta, P; Kataoka, S U; Katayama, N; Kawai, H; Kawasaki, T; Kibayashi, A; Kichimi, H; Kim, H J; Kim, H O; Kim, J H; Kim, S K; Kim, Y J; Kinoshita, K; Korpar, S; Kozakai, Y; Krizan, P; Krokovny, P; Kumar, R; Kurihara, E; Kusaka, A; Kuzmin, A; Kwon, Y J; Lange, J S; Leder, G; Lee, J; Lee, J S; Lee, M J; Lee, S E; Lesiak, T; Li, J; Limosani, A; Lin, S W; Liu, Y; Liventsev, D; MacNaughton, J; Majumder, G; Mandl, F; Marlow, D; Matsumura, T; Matyja, A; McOnie, S; Medvedeva, T; Mikami, Y; Mitaroff, W A; Miyabayashi, K; Miyake, H; Miyata, H; Miyazaki, Y; Mizuk, R; Moloney, G R; Mori, T; Müller, J; Murakami, A; Nagamine, T; Nagasaka, Y; Nakahama, Y; Nakamura, I; Nakano, E; Nakao, M; Nakayama, H; Nakazawa, H; Natkaniec, Z; Neichi, K; Nishida, S; Nishimura, K; Nishio, Y; Nishizawa, I; Nitoh, O; Noguchi, S; Nozaki, T; Ogawa, A; Ogawa, S; Ohshima, T; Okuno, S; Olsen, S L; Ono, S; Ostrowicz, W; Ozaki, H; Pakhlov, P; Pakhlova, G; Palka, H; Park, C W; Park, H; Park, K S; Parslow, N; Peak, L S; Pernicka, M; Pestotnik, R; Peters, M; Piilonen, L E; Poluektov, A; Rorie, J; Rózanska, M; Sahoo, H; Sakai, Y; Sakaue, H; Sasao, N; Sarangi, T R; Satoyama, N; Sayeed, K; Schietinger, T; Schneider, O; Schonmeier, P; Schümann, J; Schwanda, C; Schwartz, A J; Seidl, R; Sekiya, A; Senyo, K; Sevior, M E; Shang, L; Shapkin, M; Shen, C P; Shibuya, H; Shinomiya, S; Shiu, J G; Shwartz, B; Singh, J B; Sokolov, A; Solovieva, E; Somov, A; Stanic, S; Staric, M; Stypula, J; Sugiyama, A; Sumisawa, K; Sumiyoshi, T; Suzuki, S; Suzuki, S Y; Tajima, O; Takasaki, F; Tamai, K; Tamura, N; Tanaka, M; Taniguchi, N; Taylor, G N; Teramoto, Y; Tikhomirov, I; Trabelsi, K; Tse, Y F; Tsuboyama, T; Uchida, K; Uchida, Y; Uehara, S; Ueno, K; Uglov, T; Unno, Y; Uno, S; Urquijo, P; Ushiroda, Y; Usov, Yu; Varner, G; Varvell, K E; Vervink, K; Villa, S; Vinokurova, A; Wang, C C; Wang, C H; Wang, J; Wang, M Z; Wang, P; Wang, X L; Watanabe, M; Watanabe, Y; Wedd, R; Wicht, J; Widhalm, L; Wiechczynski, J; Won, E; Yabsley, B D; Yamaguchi, A; Yamamoto, H; Yamaoka, M; Yamashita, Y; Yamauchi, M; Yuan, C Z; Yusa, Y; Zhang, C C; Zhang, L M; Zhang, Z P; Zhilich, V; Zhulanov, V; Zupanc, A; Zwahlen, N

    2007-01-01

    We present preliminary results for the branching fraction B(Ds -> munu) using a 548 fb^-1 data sample collected by the Belle experiment at the KEKB e+e- collider. The Ds momentum is determined by full reconstruction of the recoil system in events of the type e+e- -> D*sDKX, D*s -> Ds gamma where X is any number of additional pions or photons from fragmentation. The full reconstruction method provides high resolution in the neutrino momentum and thus good background separation, equivalent to that reached at experiments at the tau-charm factories such as CLEO-c or BES. We obtain the preliminary branching fraction B(Ds -> munu) = (6.44 +- 0.76 (stat) +- 0.52 (syst)) x 10^(-3), implying a Ds decay constant of f_Ds = 275 +- 16 (stat) +- 12 (syst) MeV.

  4. The ISS Sensitizing Agents Data Bank (BDS).

    Science.gov (United States)

    Brunetto, Barbara; Binetti, Roberto; Ceccarelli, Federica; Costamagna, Francesca Marina; D'Angiolini, Antonella; Fabri, Alessandra; Ferri, Maurizio; Marcello, Ida; Riva, Giovanni; Roazzi, Paolo; Trucchi, Daniela; Tinghino, Raffaella

    2008-01-01

    The Istituto Superiore Sanità has developed a data bank on sensitizing substances (Banca Dati Sensibilizzanti, BDS), available on website (www.iss.it/bdse/), sharing complete, controlled and updated information coming from different sources, such as scientific publications, international agencies and governmental or non governmental organizations. It is worthwhile that the main objective of the BDS is not the classification of sensitizing or potentially sensitizing agents within specific risk classes, but it is essentially to provide concise and non confidential information related to this endpoint. At present, the BDS includes: all the substances officially classified by European Union, (Annex I to Directive 67/548/EEC), some substances listed in I (Directive 67/548/EEC) for endpoints different than "sensitization" but indicated as sensitizers by other relevant institutions, all the substances indicated as sensitizers by relevant agencies or institutions (ACGIH, DFG), some substances indicted as sensitizers by industry and other non-governmental organizations (ETAD and HERA), all the substances regarded as "potentially sensitizing dyes" by the Commission of the European Community for the award of the eco-label to textile products, some substances for which, even in the absence of any categorization by Union, ACGIH or DFG, it is not possible to exclude a sensitizing potential on the basis of reliable documents.

  5. The BDS iGMAS RIOS station at Observatório Nacional, Rio de Janeiro

    Science.gov (United States)

    Humberto Andrei, Alexandre; Song, Shuli; Junqueira, Selma; Beauvalet, Laurene

    2016-07-01

    position of the satellites by analyzing the pseudo-ranges obtained by C1W code for GPS, and C7I code for BDS. Using the Allan variation a crucial result is obtained. It is shown that the BDS system can perform at the level of the GPS system, provided equal satellite coverage. On the other hand at the Observatório Nacional it is detected a near constant bias of about 35m between the ranges simultaneously derived from the RIOS (iGMAS) and RJEP (GNSS) stations, no matter the observed satellite, or constellation. Both results are presented and discussed. We also present the current status of the installation of a second BDS iGMAS station, in a northern, equatorial location in Brazil. The operational and scientific perspectives are disclosed.

  6. Bacterial contamination of platelet concentrates: pathogen detection and inactivation methods

    Directory of Open Access Journals (Sweden)

    Dana Védy

    2009-04-01

    Full Text Available Whereas the reduction of transfusion related viral transmission has been a priority during the last decade, bacterial infection transmitted by transfusion still remains associated to a high morbidity and mortality, and constitutes the most frequent infectious risk of transfusion. This problem especially concerns platelet concentrates because of their favorable bacterial growth conditions. This review gives an overview of platelet transfusion-related bacterial contamination as well as on the different strategies to reduce this problem by using either bacterial detection or inactivation methods.

  7. Bacteriophage Amplification-Coupled Detection and Identification of Bacterial Pathogens

    Science.gov (United States)

    Cox, Christopher R.; Voorhees, Kent J.

    Current methods of species-specific bacterial detection and identification are complex, time-consuming, and often require expensive specialized equipment and highly trained personnel. Numerous biochemical and genotypic identification methods have been applied to bacterial characterization, but all rely on tedious microbiological culturing practices and/or costly sequencing protocols which render them impractical for deployment as rapid, cost-effective point-of-care or field detection and identification methods. With a view towards addressing these shortcomings, we have exploited the evolutionarily conserved interactions between a bacteriophage (phage) and its bacterial host to develop species-specific detection methods. Phage amplification-coupled matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS) was utilized to rapidly detect phage propagation resulting from species-specific in vitro bacterial infection. This novel signal amplification method allowed for bacterial detection and identification in as little as 2 h, and when combined with disulfide bond reduction methods developed in our laboratory to enhance MALDI-TOF-MS resolution, was observed to lower the limit of detection by several orders of magnitude over conventional spectroscopy and phage typing methods. Phage amplification has been combined with lateral flow immunochromatography (LFI) to develop rapid, easy-to-operate, portable, species-specific point-of-care (POC) detection devices. Prototype LFI detectors have been developed and characterized for Yersinia pestis and Bacillus anthracis, the etiologic agents of plague and anthrax, respectively. Comparable sensitivity and rapidity was observed when phage amplification was adapted to a species-specific handheld LFI detector, thus allowing for rapid, simple, POC bacterial detection and identification while eliminating the need for bacterial culturing or DNA isolation and amplification techniques.

  8. Analysis and compensation for code Doppler effect of BDS II signal under high dynamics

    Science.gov (United States)

    Ouyang, Xiaofeng; Zeng, Fangling

    2016-01-01

    In high dynamic circumstances, the acquisition of BDS (BeiDou Navigation Satellite System) signal would be affected by the pseudo-code Doppler. The pseudo-code frequency shift is more prominent and complex when BOC modulation has been adopted by BDS-II, but is not yet involved in current compensation algorithm. In addition, the most frequently used code Doppler compensation algorithm is modifying the sampling rate or local bit rate, which not only increases the complexity of the acquisition and tracking, but also is barely realizable for the hardware receiver to modify the local frequency. Therefore, this paper proposes a code Doppler compensation method based on double estimator receiver, which simultaneously controls NCO delay of code tracking loop and subcarrier tracking loop to compensate for pseudo-code frequency shift. The simulation and test are implemented with BDS-II BOC signal. The test results demonstrate that the proposed algorithm can effectively compensate for pseudo-code Doppler of BOC signal and has detection probability 3dB higher than the uncompensated situation when the false alarm rate is under 0.01 and the coherent integration time is 1ms.

  9. Contribution Analysis of BDS/GPS Combined Orbit Determination

    Science.gov (United States)

    Zhang, Qin

    2016-07-01

    BeiDou Navigation Satellite System (BDS) does not have the ability of global navigation and positioning currently. The whole tracking observation of satellite orbit and the geometry of reference station are not perfect. These situations influence the accuracy of satellite orbit determination. Based on the theory and method of dynamic orbit determination, the analytical contribution of multi-GNSS combined orbit determination to the solution precision of parameters was derived. And using the measured data, the statistical contribution of BDS/GPS combined orbit determination to the solution precision of orbit and clock error was analyzed. The results show that the contribution of combined orbit determination to the solution precision of the common parameters between different systems was significant. The solution precisions of the orbit and clock error were significantly improved except GEO satellites. The statistical contribution of BDS/GPS combined orbit determination to the precision of BDS satellite orbit, the RMS of BDS satellite clock error and the RMS of receiver clock error were 36.21%, 26.88% and 20.88% respectively. Especially, the contribution to the clock error of receivers which were in the area with few visible satellites was particularly significant. And the statistical contribution was 45.95%.

  10. Illuminating the detection chain of bacterial bioreporters

    NARCIS (Netherlands)

    Meer, J.R. van der; Tropel, D.; Jaspers, M.

    2004-01-01

    Engineering bacteria for measuring chemicals of environmental or toxicological concern (bioreporter bacteria) has grown slowly into a mature research area. Despite many potential advantages, current bioreporters do not perform well enough to comply with environmental detection standards. Basically,

  11. The PPP Precision Analysis Based on BDS Regional Navigation System

    Directory of Open Access Journals (Sweden)

    ZHU Yongxing

    2015-04-01

    Full Text Available BeiDou navigation satellite system(BDS has opened service in most of the Asia-Pacific region, it offers the possibility to break the technological monopoly of GPS in the field of high-precision applications, so its performance of precise point positioning (PPP has been a great concern. Firstly, the constellation of BeiDou regional navigation system and BDS/GPS tracking network is introduced. Secondly, the precise ephemeris and clock offset accuracy of BeiDou satellite based on domestic tracking network is analyzed. Finally, the static and kinematic PPP accuracy is studied, and compared with the GPS. The actual measured numerical example shows that the static and kinematic PPP based on BDS can achieve centimeter-level and decimeter-level respectively, reaching the current level of GPS precise point positioning.

  12. Microfluidic immunomagnetic separation for enhanced bacterial detection

    DEFF Research Database (Denmark)

    Hoyland, James; Kunstmann-Olsen, Casper; Ahmed, Shakil;

    A combined lab-on-a-chip approach combining immunomagnetic separation (IMS) and flow cytometry was developed for the enrichment and detection of salmonella contamination in food samples. Immunomagnetic beads were immobilized in chips consisting of long fractal meanders while contaminated samples ...... to obtain maximum capturing efficiency. The effects of channel volume, path length and number of bends of microfluidic chip on IMS efficiency were also determined....

  13. Detection of Bacterial Endospores in Soil by Terbium Fluorescence

    Directory of Open Access Journals (Sweden)

    Andrea Brandes Ammann

    2011-01-01

    Full Text Available Spore formation is a survival mechanism of microorganisms when facing unfavorable environmental conditions resulting in “dormant” states. We investigated the occurrence of bacterial endospores in soils from various locations including grasslands (pasture, meadow, allotment gardens, and forests, as well as fluvial sediments. Bacterial spores are characterized by their high content of dipicolinic acid (DPA. In the presence of terbium, DPA forms a complex showing a distinctive photoluminescence spectrum. DPA was released from soil by microwaving or autoclaving. The addition of aluminium chloride reduced signal quenching by interfering compounds such as phosphate. The highest spore content (up to 109 spores per gram of dry soil was found in grassland soils. Spore content is related to soil type, to soil depth, and to soil carbon-to-nitrogen ratio. Our study might provide a basis for the detection of “hot spots” of bacterial spores in soil.

  14. Bacteriophage functional genomics and its role in bacterial pathogen detection.

    Science.gov (United States)

    Klumpp, Jochen; Fouts, Derrick E; Sozhamannan, Shanmuga

    2013-07-01

    Emerging and reemerging bacterial infectious diseases are a major public health concern worldwide. The role of bacteriophages in the emergence of novel bacterial pathogens by horizontal gene transfer was highlighted by the May 2011 Escherichia coli O104:H4 outbreaks that originated in Germany and spread to other European countries. This outbreak also highlighted the pivotal role played by recent advances in functional genomics in rapidly deciphering the virulence mechanism elicited by this novel pathogen and developing rapid diagnostics and therapeutics. However, despite a steady increase in the number of phage sequences in the public databases, boosted by the next-generation sequencing technologies, few functional genomics studies of bacteriophages have been conducted. Our definition of 'functional genomics' encompasses a range of aspects: phage genome sequencing, annotation and ascribing functions to phage genes, prophage identification in bacterial sequences, elucidating the events in various stages of phage life cycle using genomic, transcriptomic and proteomic approaches, defining the mechanisms of host takeover including specific bacterial-phage protein interactions and identifying virulence and other adaptive features encoded by phages and finally, using prophage genomic information for bacterial detection/diagnostics. Given the breadth and depth of this definition and the fact that some of these aspects (especially phage-encoded virulence/adaptive features) have been treated extensively in other reviews, we restrict our focus only on certain aspects. These include phage genome sequencing and annotation, identification of prophages in bacterial sequences and genetic characterization of phages, functional genomics of the infection process and finally, bacterial identification using genomic information.

  15. Bacteriophage functional genomics and its role in bacterial pathogen detection.

    Science.gov (United States)

    Klumpp, Jochen; Fouts, Derrick E; Sozhamannan, Shanmuga

    2013-07-01

    Emerging and reemerging bacterial infectious diseases are a major public health concern worldwide. The role of bacteriophages in the emergence of novel bacterial pathogens by horizontal gene transfer was highlighted by the May 2011 Escherichia coli O104:H4 outbreaks that originated in Germany and spread to other European countries. This outbreak also highlighted the pivotal role played by recent advances in functional genomics in rapidly deciphering the virulence mechanism elicited by this novel pathogen and developing rapid diagnostics and therapeutics. However, despite a steady increase in the number of phage sequences in the public databases, boosted by the next-generation sequencing technologies, few functional genomics studies of bacteriophages have been conducted. Our definition of 'functional genomics' encompasses a range of aspects: phage genome sequencing, annotation and ascribing functions to phage genes, prophage identification in bacterial sequences, elucidating the events in various stages of phage life cycle using genomic, transcriptomic and proteomic approaches, defining the mechanisms of host takeover including specific bacterial-phage protein interactions and identifying virulence and other adaptive features encoded by phages and finally, using prophage genomic information for bacterial detection/diagnostics. Given the breadth and depth of this definition and the fact that some of these aspects (especially phage-encoded virulence/adaptive features) have been treated extensively in other reviews, we restrict our focus only on certain aspects. These include phage genome sequencing and annotation, identification of prophages in bacterial sequences and genetic characterization of phages, functional genomics of the infection process and finally, bacterial identification using genomic information. PMID:23520178

  16. Bacterial Flora of Osteoradionecrosis Detected by Molecular techniques

    OpenAIRE

    2006-01-01

    The following is a report of a study undertaken to identify the bacterial species in bone samples from patients suffering from osteoradionecrosis. This was done using polymerase chain reaction (PCR), cloning and sequencing techniques, where 16S rRNA was the gene used for analysis. The results from two patient samples will be presented. As far as we know, this is the first study that includes molecular genetic techniques to detect bacteria associated with osteoradionecrosis.

  17. Molecular Detection of Common Bacterial Pathogens Causing Meningitis

    Directory of Open Access Journals (Sweden)

    H Sadighian

    2009-03-01

    Full Text Available "nBackground: The clinical diagnosis of meningitis is crucial, particularly in children. The early diagnosis and empiric an­tibi­otic treatments have led to a reduction in morbidity and mortality rates. PCR and the enzymatic digestion of 16SrDNA frag­ment which is produced by universal primers led up fast and sensitive determination. The purpose of this study was to investi­gate a rapid method for detection of common bacterial pathogens causing meningitis."nMethods: According to the gene encoding 16SrDNA found in all bacteria, a pair of primers was designed. Then the univer­sal PCR was performed for bacterial agents of meningitis (Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influ­enzae, etc. by employing broad- range DNA extraction method. The ob­tained uni­versal PCR products were digested with restriction enzymes (HaeIII, AluI and MnlI to identify bacterial species. "nResults: By the enzymatic digestion of the universal products of each standard strain of the above bacteria, specific patterns were achieved. These specific patterns may be used for comparison in CSF examination. The analytical sensitivity of the as­say was approximately 1.5´102 CFU/ml of CSF even in samples with high amount of proteins. Conclusion: The universal PCR coupled with enzymatic digestion can be used to detect and identify bacterial pathogens in clini­cal specimens rapidly and accurately. Molecular diagnostic of bacterial meningitis, though expensive and labor-inten­sive, but is valuable and critical in patient management.

  18. Rapid Bacterial Detection via an All-Electronic CMOS Biosensor

    Science.gov (United States)

    Nikkhoo, Nasim; Cumby, Nichole; Gulak, P. Glenn; Maxwell, Karen L.

    2016-01-01

    The timely and accurate diagnosis of infectious diseases is one of the greatest challenges currently facing modern medicine. The development of innovative techniques for the rapid and accurate identification of bacterial pathogens in point-of-care facilities using low-cost, portable instruments is essential. We have developed a novel all-electronic biosensor that is able to identify bacteria in less than ten minutes. This technology exploits bacteriocins, protein toxins naturally produced by bacteria, as the selective biological detection element. The bacteriocins are integrated with an array of potassium-selective sensors in Complementary Metal Oxide Semiconductor technology to provide an inexpensive bacterial biosensor. An electronic platform connects the CMOS sensor to a computer for processing and real-time visualization. We have used this technology to successfully identify both Gram-positive and Gram-negative bacteria commonly found in human infections. PMID:27618185

  19. Rapid Bacterial Detection via an All-Electronic CMOS Biosensor.

    Science.gov (United States)

    Nikkhoo, Nasim; Cumby, Nichole; Gulak, P Glenn; Maxwell, Karen L

    2016-01-01

    The timely and accurate diagnosis of infectious diseases is one of the greatest challenges currently facing modern medicine. The development of innovative techniques for the rapid and accurate identification of bacterial pathogens in point-of-care facilities using low-cost, portable instruments is essential. We have developed a novel all-electronic biosensor that is able to identify bacteria in less than ten minutes. This technology exploits bacteriocins, protein toxins naturally produced by bacteria, as the selective biological detection element. The bacteriocins are integrated with an array of potassium-selective sensors in Complementary Metal Oxide Semiconductor technology to provide an inexpensive bacterial biosensor. An electronic platform connects the CMOS sensor to a computer for processing and real-time visualization. We have used this technology to successfully identify both Gram-positive and Gram-negative bacteria commonly found in human infections. PMID:27618185

  20. Nucleic acid detection technologies and marker molecules in bacterial diagnostics.

    Science.gov (United States)

    Scheler, Ott; Glynn, Barry; Kurg, Ants

    2014-05-01

    There is a growing need for quick and reliable methods for microorganism detection and identification worldwide. Although traditional culture-based technologies are trustworthy and accurate at a relatively low cost, they are also time- and labor-consuming and are limited to culturable bacteria. Those weaknesses have created a necessity for alternative technologies that are capable for faster and more precise bacterial identification from medical, food or environmental samples. The most common current approach is to analyze the nucleic acid component of analyte solution and determine the bacterial composition according to the specific nucleic acid profiles that are present. This review aims to give an up-to-date overview of different nucleic acid target sequences and respective analytical technologies.

  1. Selective detection of bacterial layers with terahertz plasmonic antennas

    CERN Document Server

    Berrier, Audrey; Nonglaton, Guillaume; Bergquist, Jonas; Rivas, Jaime Gómez

    2012-01-01

    Current detection and identification of micro-organisms is based on either rather unspecific rapid microscopy or on more accurate complex, time-consuming procedures. In a medical context, the determination of the bacteria Gram type is of significant interest. The diagnostic of microbial infection often requires the identification of the microbiological agent responsible for the infection, or at least the identification of its family (Gram type), in a matter of minutes. In this work, we propose to use terahertz frequency range antennas for the enhanced selective detection of bacteria types. Several microorganisms are investigated by terahertz time-domain spectroscopy: a fast, contactless and damage-free investigation method to gain information on the presence and the nature of the microorganisms. We demonstrate that plasmonic antennas enhance the detection sensitivity for bacterial layers and allow the selective recognition of the Gram type of the bacteria.

  2. Selective detection of bacterial layers with terahertz plasmonic antennas.

    Science.gov (United States)

    Berrier, Audrey; Schaafsma, Martijn C; Nonglaton, Guillaume; Bergquist, Jonas; Rivas, Jaime Gómez

    2012-11-01

    Current detection and identification of micro-organisms is based on either rather unspecific rapid microscopy or on more accurate but complex and time-consuming procedures. In a medical context, the determination of the bacteria Gram type is of significant interest. The diagnostic of microbial infection often requires the identification of the microbiological agent responsible for the infection, or at least the identification of its family (Gram type), in a matter of minutes. In this work, we propose to use terahertz frequency range antennas for the enhanced selective detection of bacteria types. Several microorganisms are investigated by terahertz time-domain spectroscopy: a fast, contactless and damage-free investigation method to gain information on the presence and the nature of the microorganisms. We demonstrate that plasmonic antennas enhance the detection sensitivity for bacterial layers and allow the selective recognition of the Gram type of the bacteria.

  3. Smart phone based bacterial detection using bio functionalized fluorescent nanoparticles

    International Nuclear Information System (INIS)

    We are describing immunochromatographic test strips with smart phone-based fluorescence readout. They are intended for use in the detection of the foodborne bacterial pathogens Salmonella spp. and Escherichia coli O157. Silica nanoparticles (SiNPs) were doped with FITC and Ru(bpy), conjugated to the respective antibodies, and then used in a conventional lateral flow immunoassay (LFIA). Fluorescence was recorded by inserting the nitrocellulose strip into a smart phone-based fluorimeter consisting of a light weight (40 g) optical module containing an LED light source, a fluorescence filter set and a lens attached to the integrated camera of the cell phone in order to acquire high-resolution fluorescence images. The images were analysed by exploiting the quick image processing application of the cell phone and enable the detection of pathogens within few minutes. This LFIA is capable of detecting pathogens in concentrations as low as 105 cfu mL−1 directly from test samples without pre-enrichment. The detection is one order of magnitude better compared to gold nanoparticle-based LFIAs under similar condition. The successful combination of fluorescent nanoparticle-based pathogen detection by LFIAs with a smart phone-based detection platform has resulted in a portable device with improved diagnosis features and having potential application in diagnostics and environmental monitoring. (author)

  4. Detection of Blood Culture Bacterial Contamination using Natural Language Processing

    Science.gov (United States)

    Matheny, Michael E.; FitzHenry, Fern; Speroff, Theodore; Hathaway, Jacob; Murff, Harvey J.; Brown, Steven H.; Fielstein, Elliot M.; Dittus, Robert S.; Elkin, Peter L.

    2009-01-01

    Microbiology results are reported in semi-structured formats and have a high content of useful patient information. We developed and validated a hybrid regular expression and natural language processing solution for processing blood culture microbiology reports. Multi-center Veterans Affairs training and testing data sets were randomly extracted and manually reviewed to determine the culture and sensitivity as well as contamination results. The tool was iteratively developed for both outcomes using a training dataset, and then evaluated on the test dataset to determine antibiotic susceptibility data extraction and contamination detection performance. Our algorithm had a sensitivity of 84.8% and a positive predictive value of 96.0% for mapping the antibiotics and bacteria with appropriate sensitivity findings in the test data. The bacterial contamination detection algorithm had a sensitivity of 83.3% and a positive predictive value of 81.8%. PMID:20351890

  5. Investigation of magnetic microdiscs for bacterial pathogen detection

    Science.gov (United States)

    Castillo-Torres, Keisha Y.; Garraud, Nicolas; Arnold, David P.; McLamore, Eric S.

    2016-05-01

    Despite strict regulations to control the presence of human pathogens in our food supply, recent foodborne outbreaks have heightened public concern about food safety and created urgency to improve methods for pathogen detection. Herein we explore a potentially portable, low-cost system that uses magnetic microdiscs for the detection of bacterial pathogens in liquid samples. The system operates by optically measuring the rotational dynamics of suspended magnetic microdiscs functionalized with pathogen-binding aptamers. The soft ferromagnetic (Ni80Fe20) microdiscs exhibit a closed magnetic spin arrangement (i.e. spin vortex) with zero magnetic stray field, leading to no disc agglomeration when in free suspension. With very high surface area for functionalization and volumes 10,000x larger than commonly used superparamagnetic nanoparticles, these 1.5-μm-diameter microdiscs are well suited for tagging, trapping, actuating, or interrogating bacterial targets. This work reports a wafer-level microfabrication process for fabrication of 600 million magnetic microdiscs per substrate and measurement of their rotational dynamics response. Additionally, the biofunctionalization of the microdiscs with DNA aptamers, subsequent binding to E. coli bacteria, and their magnetic manipulation is reported.

  6. Detection of bacterial pathogens in environmental samples using DNA microarrays.

    Science.gov (United States)

    Call, Douglas R; Borucki, Monica K; Loge, Frank J

    2003-05-01

    Polymerase chain reaction (PCR) is an important tool for pathogen detection, but historically, it has not been possible to accurately identify PCR products without sequencing, Southern blots, or dot-blots. Microarrays can be coupled with PCR where they serve as a set of parallel dot-blots to enhance product detection and identification. Microarrays are composed of many discretely located probes on a solid substrate such as glass. Each probe is composed of a sequence that is complimentary to a pathogen-specific gene sequence. PCR is used to amplify one or more genes and the products are then hybridized to the array to identify species-specific polymorphism within one or more genes. We illustrate this type of array using 16S rDNA probes suitable for distinguishing between several salmonid pathogens. We also describe the use of microarrays for direct detection of either RNA or DNA without the aid of PCR, although the sensitivity of these systems currently limits their application for pathogen detection. Finally, microarrays can also be used to "fingerprint" bacterial isolates and they can be used to identify diagnostic markers suitable for developing new PCR-based detection assays. We illustrate this type of array for subtyping an important food-borne pathogen, Listeria monocytogenes. PMID:12654494

  7. Detecting Bacterial Surface Organelles on Single Cells Using Optical Tweezers.

    Science.gov (United States)

    Zakrisson, Johan; Singh, Bhupender; Svenmarker, Pontus; Wiklund, Krister; Zhang, Hanqing; Hakobyan, Shoghik; Ramstedt, Madeleine; Andersson, Magnus

    2016-05-10

    Bacterial cells display a diverse array of surface organelles that are important for a range of processes such as intercellular communication, motility and adhesion leading to biofilm formation, infections, and bacterial spread. More specifically, attachment to host cells by Gram-negative bacteria are mediated by adhesion pili, which are nanometers wide and micrometers long fibrous organelles. Since these pili are significantly thinner than the wavelength of visible light, they cannot be detected using standard light microscopy techniques. At present, there is no fast and simple method available to investigate if a single cell expresses pili while keeping the cell alive for further studies. In this study, we present a method to determine the presence of pili on a single bacterium. The protocol involves imaging the bacterium to measure its size, followed by predicting the fluid drag based on its size using an analytical model, and thereafter oscillating the sample while a single bacterium is trapped by an optical tweezer to measure its effective fluid drag. Comparison between the predicted and the measured fluid drag thereby indicate the presence of pili. Herein, we verify the method using polymer coated silica microspheres and Escherichia coli bacteria expressing adhesion pili. Our protocol can in real time and within seconds assist single cell studies by distinguishing between piliated and nonpiliated bacteria. PMID:27088225

  8. Target-specific capture enhances sensitivity of electrochemical detection of bacterial pathogens.

    Science.gov (United States)

    Patel, Mayank; Gonzalez, Rodrigo; Halford, Colin; Lewinski, Michael A; Landaw, Elliot M; Churchill, Bernard M; Haake, David A

    2011-12-01

    We report the concentration and purification of bacterial 16S rRNA by the use of a biotinylated DNA target-specific capture (TSC) probe. For both cultivated bacterial and urine specimens from urinary tract infection patients, TSC resulted in a 5- to 8-fold improvement in the sensitivity of bacterial detection in a 16S rRNA electrochemical sensor assay.

  9. Discontinuities of BFKL amplitudes and the BDS ansatz

    Science.gov (United States)

    Fadin, V. S.; Fiore, R.

    2015-12-01

    We perform an examination of discontinuities of multiple production amplitudes, which are required for further development of the BFKL approach. It turns out that the discontinuities of 2 → 2 + n amplitudes obtained in the BFKL approach contradict to the BDS ansatz for amplitudes with maximal helicity violation in N = 4 supersymmetric Yang-Mills theory with large number of colors starting with n = 2. Explicit expressions for the discontinuities of the 2 → 3 and 2 → 4 amplitudes in the invariant mass of pairs of produced gluons are obtained in the planar N = 4 SYM in the next-to-leading logarithmic approximation. These expressions can be used for checking the conjectured duality between the light-like Wilson loops and the MHV amplitudes.

  10. Procalcitonin for detecting community-acquired bacterial pneumonia

    OpenAIRE

    Devi Gusmaiyanto; Finny Fitry Yani; Efrida Efrida; Rizanda Machmud

    2016-01-01

    Background Pneumonia is a major cause of morbidity andmortality in children under five years of age. Pneumonia can be ofbacterial or viral origin. It is difficult to distinguish between thesetwo agents based on clinical manifestations, as well as radiologicaland laboratory examinations. Furthermore, bacterial cultures taketime to incubate and positive results may only be found in 10-30%of bacterial pneumonia cases. Procalcitonin has been used as amarker to distinguish etiologies, as bacterial...

  11. Biomimetic/Optical Sensors for Detecting Bacterial Species

    Science.gov (United States)

    Homer, Margie; Ksendzov, Alexander; Yen, Shiao-Pin; Ryan, Margaret; Lazazzera, Beth

    2006-01-01

    Biomimetic/optical sensors have been proposed as means of real-time detection of bacteria in liquid samples through real-time detection of compounds secreted by the bacteria. Bacterial species of interest would be identified through detection of signaling compounds unique to those species. The best-characterized examples of quorum-signaling compounds are acyl-homoserine lactones and peptides. Each compound, secreted by each bacterium of an affected species, serves as a signal to other bacteria of the same species to engage in a collective behavior when the population density of that species reaches a threshold level analogous to a quorum. A sensor according to the proposal would include a specially formulated biomimetic film, made of a molecularly imprinted polymer (MIP), that would respond optically to the signaling compound of interest. The MIP film would be integrated directly onto an opticalwaveguide- based ring resonator for optical readout. Optically, the sensor would resemble the one described in Chemical Sensors Based on Optical Ring Resonators (NPO-40601), NASA Tech Briefs, Vol. 29, No. 10 (October 2005), page 32. MIPs have been used before as molecular- recognition compounds, though not in the manner of the present proposal. Molecular imprinting is an approach to making molecularly selective cavities in a polymer matrix. These cavities function much as enzyme receptor sites: the chemical functionality and shape of a cavity in the polymer matrix cause the cavity to bind to specific molecules. An MIP matrix is made by polymerizing monomers in the presence of the compound of interest (template molecule). The polymer forms around the template. After the polymer solidifies, the template molecules are removed from the polymer matrix by decomplexing them from their binding sites and then dissolving them, leaving cavities that are matched to the template molecules in size, shape, and chemical functionality. The cavities thus become molecular-recognition sites

  12. Procalcitonin for detecting community-acquired bacterial pneumonia

    Directory of Open Access Journals (Sweden)

    Devi Gusmaiyanto

    2015-03-01

    Full Text Available Background Pneumonia is a major cause of morbidity and mortality in children under five years of age. Pneumonia can be of bacterial or viral origin. It is difficult to distinguish between these two agents based on clinical manifestations, as well as radiological and laboratory examinations. Furthermore, bacterial cultures take time to incubate and positive results may only be found in 10-30% of bacterial pneumonia cases. Procalcitonin has been used as a marker to distinguish etiologies, as bacterial infections tend to increase serum procalcitonin levels. Objective To determine the sensitivity, specificity, positive predictive value and negative predictive value of procalcitonin in community-acquired bacterial pneumonia. Method This cross-sectional study was conducted in the Pediatric Health Department of Dr. M. Djamil Hospital, Padang. Subjects were selected by consecutive sampling. Procalcitonin measurements and PCR screening were performed on blood specimens from 32 pneumonia patients and compared. Results Of the 32 subjects, most were boys (56.25%, under 5 years of age (99%, and had poor nutritional status (68.75%. Using a cut-off point of 0.25 ng/mL, procalcitonin level had a sensitivity of 92%, specificity 50%, positive predictive value 88%, and negative predictive value 60% for diagnosing bacterial pneumonia. Using a cut-off point of 0.5 ng/mL, procalcitonin level had a specificity of 46%, specificity 83%, positive predictive value 91%, and negative predictive value 25%. Conclusion A cut-off point of 0.25 ng/mL of procalcitonin level may be more useful to screen for bacterial pneumonia than a cut-off point of 0.5 ng / mL. However, if the 0.25 ng/mL cut-off point is used, careful monitoring will be required for negative results, as up to 40% may actually have bacterial pneumonia. [Paediatr Indones. 2015;55:65-9.].

  13. Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations

    Directory of Open Access Journals (Sweden)

    Wang Gao

    2015-10-01

    Full Text Available The regional constellation of the BeiDou navigation satellite system (BDS has been providing continuous positioning, navigation and timing services since 27 December 2012, covering China and the surrounding area. Real-time kinematic (RTK positioning with combined BDS and GPS observations is feasible. Besides, all satellites of BDS can transmit triple-frequency signals. Using the advantages of multi-pseudorange and carrier observations from multi-systems and multi-frequencies is expected to be of much benefit for ambiguity resolution (AR. We propose an integrated AR strategy for medium baselines by using the combined GPS and BDS dual/triple-frequency observations. In the method, firstly the extra-wide-lane (EWL ambiguities of triple-frequency system, i.e., BDS, are determined first. Then the dual-frequency WL ambiguities of BDS and GPS were resolved with the geometry-based model by using the BDS ambiguity-fixed EWL observations. After that, basic (i.e., L1/L2 or B1/B2 ambiguities of BDS and GPS are estimated together with the so-called ionosphere-constrained model, where the ambiguity-fixed WL observations are added to enhance the model strength. During both of the WL and basic AR, a partial ambiguity fixing (PAF strategy is adopted to weaken the negative influence of new-rising or low-elevation satellites. Experiments were conducted and presented, in which the GPS/BDS dual/triple-frequency data were collected in Nanjing and Zhengzhou of China, with the baseline distance varying from about 28.6 to 51.9 km. The results indicate that, compared to the single triple-frequency BDS system, the combined system can significantly enhance the AR model strength, and thus improve AR performance for medium baselines with a 75.7% reduction of initialization time on average. Besides, more accurate and stable positioning results can also be derived by using the combined GPS/BDS system.

  14. Procalcitonin for detecting community-acquired bacterial pneumonia

    Directory of Open Access Journals (Sweden)

    Devi Gusmaiyanto

    2016-06-01

    Full Text Available Background Pneumonia is a major cause of morbidity andmortality in children under five years of age. Pneumonia can be ofbacterial or viral origin. It is difficult to distinguish between thesetwo agents based on clinical manifestations, as well as radiologicaland laboratory examinations. Furthermore, bacterial cultures taketime to incubate and positive results may only be found in 10-30%of bacterial pneumonia cases. Procalcitonin has been used as amarker to distinguish etiologies, as bacterial infections tend toincrease serum procalcitonin levels.Objective To determine the sensitivity, specificity, positivepredictive value and negative predictive value of procalcitoninin community-acquired bacterial pneumonia.Method This cross-sectional study was conducted in thePediatric Health Department of Dr. M. Djamil Hospital, Padang.Subjects were selected by consecutive sampling. Procalcitoninmeasurements and PCR screening were performed on bloodspecimens from 32 pneumonia patients and compared.Results Of the 32 subjects, most were boys (56.25%, under 5years of age (99%, and had poor nutritional status (68.75%.Using a cut-off point of 0.25 ng/mL, procalcitonin level hada sensitivity of 92%, specificity 50%, positive predictive value 88%, and negative predictive value 60% for diagnosing bacterial pneumonia. Using a cut-off point of 0.5 ng/mL, procalcitonin level had a specificity of 46%, specificity 83%, positive predictive value 91%, and negative predictive value 25%.Conclusion A cut-off point of 0.25 ng/mL of procalcitonin level may be more useful to screen for bacterial pneumonia than a cutoff point of 0.5 ng / mL. However, if the 0.25 ng/mL cut-off point is used, careful monitoring will be required for negative results, as up to 40% may actually have bacterial pneumonia. [PaediatrIndones. 2015;55:65-9.].

  15. Molecular detection of bacterial pathogens using microparticle enhanced double-stranded DNA probes.

    Science.gov (United States)

    Riahi, Reza; Mach, Kathleen E; Mohan, Ruchika; Liao, Joseph C; Wong, Pak Kin

    2011-08-15

    Rapid, specific, and sensitive detection of bacterial pathogens is essential toward clinical management of infectious diseases. Traditional approaches for pathogen detection, however, often require time-intensive bacterial culture and amplification procedures. Herein, a microparticle enhanced double-stranded DNA probe is demonstrated for rapid species-specific detection of bacterial 16S rRNA. In this molecular assay, the binding of the target sequence to the fluorophore conjugated probe thermodynamically displaces the quencher probe and allows the fluorophore to fluoresce. By incorporation of streptavidin-coated microparticles to localize the biotinylated probes, the sensitivity of the assay can be improved by 3 orders of magnitude. The limit of detection of the assay is as few as eight bacteria without target amplification and is highly specific against other common pathogens. Its applicability toward clinical diagnostics is demonstrated by directly identifying bacterial pathogens in urine samples from patients with urinary tract infections.

  16. Modeling and Assessment of GPS/BDS Combined Precise Point Positioning

    Science.gov (United States)

    Chen, Junping; Wang, Jungang; Zhang, Yize; Yang, Sainan; Chen, Qian; Gong, Xiuqiang

    2016-01-01

    Precise Point Positioning (PPP) technique enables stand-alone receivers to obtain cm-level positioning accuracy. Observations from multi-GNSS systems can augment users with improved positioning accuracy, reliability and availability. In this paper, we present and evaluate the GPS/BDS combined PPP models, including the traditional model and a simplified model, where the inter-system bias (ISB) is treated in different way. To evaluate the performance of combined GPS/BDS PPP, kinematic and static PPP positions are compared to the IGS daily estimates, where 1 month GPS/BDS data of 11 IGS Multi-GNSS Experiment (MGEX) stations are used. The results indicate apparent improvement of GPS/BDS combined PPP solutions in both static and kinematic cases, where much smaller standard deviations are presented in the magnitude distribution of coordinates RMS statistics. Comparisons between the traditional and simplified combined PPP models show no difference in coordinate estimations, and the inter system biases between the GPS/BDS system are assimilated into receiver clock, ambiguities and pseudo-range residuals accordingly. PMID:27455278

  17. Modeling and Assessment of GPS/BDS Combined Precise Point Positioning.

    Science.gov (United States)

    Chen, Junping; Wang, Jungang; Zhang, Yize; Yang, Sainan; Chen, Qian; Gong, Xiuqiang

    2016-07-22

    Precise Point Positioning (PPP) technique enables stand-alone receivers to obtain cm-level positioning accuracy. Observations from multi-GNSS systems can augment users with improved positioning accuracy, reliability and availability. In this paper, we present and evaluate the GPS/BDS combined PPP models, including the traditional model and a simplified model, where the inter-system bias (ISB) is treated in different way. To evaluate the performance of combined GPS/BDS PPP, kinematic and static PPP positions are compared to the IGS daily estimates, where 1 month GPS/BDS data of 11 IGS Multi-GNSS Experiment (MGEX) stations are used. The results indicate apparent improvement of GPS/BDS combined PPP solutions in both static and kinematic cases, where much smaller standard deviations are presented in the magnitude distribution of coordinates RMS statistics. Comparisons between the traditional and simplified combined PPP models show no difference in coordinate estimations, and the inter system biases between the GPS/BDS system are assimilated into receiver clock, ambiguities and pseudo-range residuals accordingly.

  18. Modeling and Assessment of GPS/BDS Combined Precise Point Positioning.

    Science.gov (United States)

    Chen, Junping; Wang, Jungang; Zhang, Yize; Yang, Sainan; Chen, Qian; Gong, Xiuqiang

    2016-01-01

    Precise Point Positioning (PPP) technique enables stand-alone receivers to obtain cm-level positioning accuracy. Observations from multi-GNSS systems can augment users with improved positioning accuracy, reliability and availability. In this paper, we present and evaluate the GPS/BDS combined PPP models, including the traditional model and a simplified model, where the inter-system bias (ISB) is treated in different way. To evaluate the performance of combined GPS/BDS PPP, kinematic and static PPP positions are compared to the IGS daily estimates, where 1 month GPS/BDS data of 11 IGS Multi-GNSS Experiment (MGEX) stations are used. The results indicate apparent improvement of GPS/BDS combined PPP solutions in both static and kinematic cases, where much smaller standard deviations are presented in the magnitude distribution of coordinates RMS statistics. Comparisons between the traditional and simplified combined PPP models show no difference in coordinate estimations, and the inter system biases between the GPS/BDS system are assimilated into receiver clock, ambiguities and pseudo-range residuals accordingly. PMID:27455278

  19. The Proposal of a BDS Syllabus Framework to Suit Choice Based Credit System (CBCS)

    Science.gov (United States)

    Sethuraman, KR; Narayan, KA

    2016-01-01

    Introduction Higher education takes a new dimension universally in the form of choice based Credit System (CBCS). In India, the University Grants Commission (UGC) has made CBCS mandatory in all fields except for Health Profession. Not much attempts were made in designing a BDS syllabus to suit CBCS. Aim Aim of the study was to propose a model dental syllabus to fit into choice based credit system. Materials and Methods A model BDS syllabus Prototype for CBCS was designed based on the UGC guidelines for terms as well as calculations for CBCS. Engineering curriculum models from IIT and Anna University were also referred to. Results Semester based BDS syllabus was designed without changing the norms of Dental Council of India (DCI). All the must know areas of the subjects were considered as “core” areas and the desirable and nice to know areas are left for “electives” by the students. By this method, none of the subject was left out at the same time students are provided with electives to learn deeper on their topics of choice. Conclusion The existing BDS syllabus can be effectively modified by incorporating few changes based on the UGC regulations for Choice based credit system. The proposed framework gives an insight on the nature of modifications that are needed. By adopting this, BDS Course regulations can also follow CBCS without neglecting or reducing the weightage of any subject. PMID:27656467

  20. Direct fluorescent antibody technique for the detection of bacterial kidney disease in paraffin-embedded tissues

    Science.gov (United States)

    Ochiai, T.; Yasutake, W.T.; Gould, R.W.

    1985-01-01

    The direct fluorescent antibody technique (FAT) was successfully used to detect the causative agent of bacterial kidney disease (BKD), Renibacterium salmoninarum, in Bouin's solution flexed and paraffinembedded egg and tissue sections. This method is superior to gram stain and may be particularly useful in detecting the BKD organism in fish with low-grade infection.

  1. Bacterial regrowth in water reclamation and distribution systems revealed by viable bacterial detection assays.

    Science.gov (United States)

    Lin, Yi-wen; Li, Dan; Gu, April Z; Zeng, Si-yu; He, Miao

    2016-02-01

    Microbial regrowth needs to be managed during water reclamation and distribution. The aim of present study was to investigate the removal and regrowth of Escherichia coli (E. coli) and Salmonella in water reclamation and distribution system by using membrane integrity assay (PMA-qPCR), reverse transcriptional activity assay (Q-RT-PCR) and culture-based assay, and also to evaluate the relationships among bacterial regrowth, and environmental factors in the distribution system. The results showed that most of the water reclamation processes potentially induced bacteria into VBNC state. The culturable E. coli and Salmonella regrew 1.8 and 0.7 log10 in distribution system, which included reactivation of bacteria in the viable but non-culturable (VBNC) state and reproduction of culturable bacteria. The regrowth of culturable E. coli and Salmonella in the distribution system mainly depended on the residual chlorine levels, with correlations (R(2)) of -0.598 and -0.660. The abundances of membrane integrity and reverse transcriptional activity bacteria in reclamation effluents had significant correlations with the culturable bacteria at the end point of the distribution system, demonstrating that PMA-qPCR and Q-RT-PCR are sensitive and accurate tools to determine and predict bacterial regrowth in water distribution systems. This study has improved our understanding of microbial removal and regrowth in reclaimed water treatment and distribution systems. And the results also recommended that more processes should be equipped to remove viable bacteria in water reclamation plants for the sake of inhibition microbial regrowth during water distribution and usages.

  2. Detection of intracellular bacterial communities in human urinary tract infection.

    Directory of Open Access Journals (Sweden)

    David A Rosen

    2007-12-01

    Full Text Available BACKGROUND: Urinary tract infections (UTIs are one of the most common bacterial infections and are predominantly caused by uropathogenic Escherichia coli (UPEC. While UTIs are typically considered extracellular infections, it has been recently demonstrated that UPEC bind to, invade, and replicate within the murine bladder urothelium to form intracellular bacterial communities (IBCs. These IBCs dissociate and bacteria flux out of bladder facet cells, some with filamentous morphology, and ultimately establish quiescent intracellular reservoirs that can seed recurrent infection. This IBC pathogenic cycle has not yet been investigated in humans. In this study we sought to determine whether evidence of an IBC pathway could be found in urine specimens from women with acute UTI. METHODS AND FINDINGS: We collected midstream, clean-catch urine specimens from 80 young healthy women with acute uncomplicated cystitis and 20 asymptomatic women with a history of UTI. Investigators were blinded to culture results and clinical history. Samples were analyzed by light microscopy, immunofluorescence, and electron microscopy for evidence of exfoliated IBCs and filamentous bacteria. Evidence of IBCs was found in 14 of 80 (18% urines from women with UTI. Filamentous bacteria were found in 33 of 80 (41% urines from women with UTI. None of the 20 urines from the asymptomatic comparative group showed evidence of IBCs or filaments. Filamentous bacteria were present in all 14 of the urines with IBCs compared to 19 (29% of 66 samples with no evidence of IBCs (p < 0.001. Of 65 urines from patients with E. coli infections, 14 (22% had evidence of IBCs and 29 (45% had filamentous bacteria, while none of the gram-positive infections had IBCs or filamentous bacteria. CONCLUSIONS: The presence of exfoliated IBCs and filamentous bacteria in the urines of women with acute cystitis suggests that the IBC pathogenic pathway characterized in the murine model may occur in humans. The

  3. BDS/GPS Dual Systems Positioning Based on the Modified SR-UKF Algorithm.

    Science.gov (United States)

    Kong, JaeHyok; Mao, Xuchu; Li, Shaoyuan

    2016-01-01

    The Global Navigation Satellite System can provide all-day three-dimensional position and speed information. Currently, only using the single navigation system cannot satisfy the requirements of the system's reliability and integrity. In order to improve the reliability and stability of the satellite navigation system, the positioning method by BDS and GPS navigation system is presented, the measurement model and the state model are described. Furthermore, the modified square-root Unscented Kalman Filter (SR-UKF) algorithm is employed in BDS and GPS conditions, and analysis of single system/multi-system positioning has been carried out, respectively. The experimental results are compared with the traditional estimation results, which show that the proposed method can perform highly-precise positioning. Especially when the number of satellites is not adequate enough, the proposed method combine BDS and GPS systems to achieve a higher positioning precision. PMID:27153068

  4. BDS/GPS Dual Systems Positioning Based on the Modified SR-UKF Algorithm

    Science.gov (United States)

    Kong, JaeHyok; Mao, Xuchu; Li, Shaoyuan

    2016-01-01

    The Global Navigation Satellite System can provide all-day three-dimensional position and speed information. Currently, only using the single navigation system cannot satisfy the requirements of the system’s reliability and integrity. In order to improve the reliability and stability of the satellite navigation system, the positioning method by BDS and GPS navigation system is presented, the measurement model and the state model are described. Furthermore, the modified square-root Unscented Kalman Filter (SR-UKF) algorithm is employed in BDS and GPS conditions, and analysis of single system/multi-system positioning has been carried out, respectively. The experimental results are compared with the traditional estimation results, which show that the proposed method can perform highly-precise positioning. Especially when the number of satellites is not adequate enough, the proposed method combine BDS and GPS systems to achieve a higher positioning precision. PMID:27153068

  5. BDS/GPS Dual Systems Positioning Based on the Modified SR-UKF Algorithm

    Directory of Open Access Journals (Sweden)

    JaeHyok Kong

    2016-05-01

    Full Text Available The Global Navigation Satellite System can provide all-day three-dimensional position and speed information. Currently, only using the single navigation system cannot satisfy the requirements of the system’s reliability and integrity. In order to improve the reliability and stability of the satellite navigation system, the positioning method by BDS and GPS navigation system is presented, the measurement model and the state model are described. Furthermore, the modified square-root Unscented Kalman Filter (SR-UKF algorithm is employed in BDS and GPS conditions, and analysis of single system/multi-system positioning has been carried out, respectively. The experimental results are compared with the traditional estimation results, which show that the proposed method can perform highly-precise positioning. Especially when the number of satellites is not adequate enough, the proposed method combine BDS and GPS systems to achieve a higher positioning precision.

  6. BDS/GPS Dual Systems Positioning Based on the Modified SR-UKF Algorithm.

    Science.gov (United States)

    Kong, JaeHyok; Mao, Xuchu; Li, Shaoyuan

    2016-05-03

    The Global Navigation Satellite System can provide all-day three-dimensional position and speed information. Currently, only using the single navigation system cannot satisfy the requirements of the system's reliability and integrity. In order to improve the reliability and stability of the satellite navigation system, the positioning method by BDS and GPS navigation system is presented, the measurement model and the state model are described. Furthermore, the modified square-root Unscented Kalman Filter (SR-UKF) algorithm is employed in BDS and GPS conditions, and analysis of single system/multi-system positioning has been carried out, respectively. The experimental results are compared with the traditional estimation results, which show that the proposed method can perform highly-precise positioning. Especially when the number of satellites is not adequate enough, the proposed method combine BDS and GPS systems to achieve a higher positioning precision.

  7. Convergence Time and Positioning Accuracy Comparison between BDS and GPS Precise Point Positioning

    Directory of Open Access Journals (Sweden)

    ZHANG Xiaohong

    2015-03-01

    Full Text Available BDS/GPS data from MGEX were processed by TriP 2.0 software developed at Wuhan University. Both static and kinematic float PPP are tested by adopting precise satellite orbits and clocks provided by Research Center of GNSS, Wuhan University. The results show that the convergence time of BDS static PPP is about 80min while kinematic PPP is about 100min. For 3h observations, static positioning accuracy of 5 cm and kinematic positioning accuracy of 8 cm in horizontal, about 12 cm in vertical can be achieved. Similar to GPS PPP, precision in east component is worse than north. At present, BDS PPP needs longer convergence time than GPS PPP to reach an absolute positioning accuracy of cm~dm due to the lack of global tracking stations and the limited accuracy of orbit and clock products.

  8. A functional gene array for detection of bacterial virulence elements.

    Directory of Open Access Journals (Sweden)

    Crystal Jaing

    Full Text Available Emerging known and unknown pathogens create profound threats to public health. Platforms for rapid detection and characterization of microbial agents are critically needed to prevent and respond to disease outbreaks. Available detection technologies cannot provide broad functional information about known or novel organisms. As a step toward developing such a system, we have produced and tested a series of high-density functional gene arrays to detect elements of virulence and antibiotic resistance mechanisms. Our first generation array targets genes from Escherichia coli strains K12 and CFT073, Enterococcus faecalis and Staphylococcus aureus. We determined optimal probe design parameters for gene family detection and discrimination. When tested with organisms at varying phylogenetic distances from the four target strains, the array detected orthologs for the majority of targeted gene families present in bacteria belonging to the same taxonomic family. In combination with whole-genome amplification, the array detects femtogram concentrations of purified DNA, either spiked in to an aerosol sample background, or in combinations from one or more of the four target organisms. This is the first report of a high density NimbleGen microarray system targeting microbial antibiotic resistance and virulence mechanisms. By targeting virulence gene families as well as genes unique to specific biothreat agents, these arrays will provide important data about the pathogenic potential and drug resistance profiles of unknown organisms in environmental samples.

  9. The hexagon Wilson loop and the BDS ansatz for the six-gluon amplitude

    OpenAIRE

    Drummond, J M; Henn, J.; Korchemsky, G.P.; Sokatchev, E.

    2007-01-01

    As a test of the gluon scattering amplitude/Wilson loop duality, we evaluate the hexagonal light-like Wilson loop at two loops in N=4 super Yang-Mills theory. We compare its finite part to the Bern-Dixon-Smirnov (BDS) conjecture for the finite part of the six-gluon amplitude. We find that the two expressions have the same behavior in the collinear limit, but they differ by a non-trivial function of the three (dual) conformally invariant variables. This implies that either the BDS conjecture o...

  10. Precise orbit determination of Multi-GNSS constellation including GPS GLONASS BDS and GALIEO

    Science.gov (United States)

    Dai, Xiaolei

    2014-05-01

    In addition to the existing American global positioning system (GPS) and the Russian global navigation satellite system (GLONASS), the new generation of GNSS is emerging and developing, such as the Chinese BeiDou satellite navigation system (BDS) and the European GALILEO system. Multi-constellation is expected to contribute to more accurate and reliable positioning and navigation service. However, the application of multi-constellation challenges the traditional precise orbit determination (POD) strategy that was designed usually for single constellation. In this contribution, we exploit a more rigorous multi-constellation POD strategy for the ongoing IGS multi-GNSS experiment (MGEX) where the common parameters are identical for each system, and the frequency- and system-specified parameters are employed to account for the inter-frequency and inter-system biases. Since the authorized BDS attitude model is not yet released, different BDS attitude model are implemented and their impact on orbit accuracy are studied. The proposed POD strategy was implemented in the PANDA (Position and Navigation Data Analyst) software and can process observations from GPS, GLONASS, BDS and GALILEO together. The strategy is evaluated with the multi-constellation observations from about 90 MGEX stations and BDS observations from the BeiDou experimental tracking network (BETN) of Wuhan University (WHU). Of all the MGEX stations, 28 stations record BDS observation, and about 80 stations record GALILEO observations. All these data were processed together in our software, resulting in the multi-constellation POD solutions. We assessed the orbit accuracy for GPS and GLONASS by comparing our solutions with the IGS final orbit, and for BDS and GALILEO by overlapping our daily orbit solution. The stability of inter-frequency bias of GLONASS and inter-system biases w.r.t. GPS for GLONASS, BDS and GALILEO were investigated. At last, we carried out precise point positioning (PPP) using the multi

  11. Comparative detection of bacterial adhesion to Caco-2 cells with ELISA, radioactivity and plate count methods.

    Science.gov (United States)

    Le Blay, Gwenaëlle; Fliss, Ismaïl; Lacroix, Christophe

    2004-11-01

    Different methods are used to study bacterial adhesion to intestinal epithelial cells, which is an important step in pathogenic infection as well as in probiotic colonization of the intestinal tract. The aim of this study was to compare the ELISA-based method with more conventional plate count and radiolabeling methods for bacterial adhesion detection. An ELISA-based assay was optimized for the detection of Bifidobacterium longum and Escherichia coli O157:H7, which are low and highly adherent bacteria, respectively. In agreement with previous investigations, a percentage of adhesion below 1% was obtained for B. longum with ELISA. However, high nonspecific background and low positive signals were measured due to the use of polyclonal antibodies and the low adhesion capacity with this strain. In contrast, the ELISA-based method developed for E. coli adhesion detected a high adhesion percentage (15%). For this bacterium the three methods tested gave similar results for the highest bacterial concentrations (6.8 Log CFU added bacteria/well). However, differences among methods increased with the addition of decreased bacterial concentration due to different detection thresholds (5.9, 5.6 and 2.9 Log CFU adherent bacteria/well for radioactivity, ELISA and plate count methods, respectively). The ELISA-based method was shown to be a good predictor for bacterial adhesion compared to the radiolabeling method when good quality specific antibodies were used. This technique is convenient and allows handling of numerous samples.

  12. Detection of Bacterial Wilt Pathogen and Isolation of Its Bacteriophage from Banana in Lumajang Area, Indonesia

    Directory of Open Access Journals (Sweden)

    Hardian Susilo Addy

    2016-01-01

    Full Text Available Bacterial wilt disease on banana is an important disease in Lumajang District and causes severe yield loss. Utilizing bacteriophage as natural enemy of pathogenic bacteria has been widely known as one of the control strategies. This research was aimed at determining the causing agent of bacterial wilt on banana isolated from Lumajang area, to obtain wide-host range bacteriophages against bacterial wilt pathogen and to know the basic characteristic of bacteriophages, particularly its nucleic acid type. Causative agent of bacterial wilt was isolated from symptomatic banana trees from seven districts in Lumajang area on determinative CPG plates followed by rapid detection by PCR technique using specific pair-primer. Bacteriophages were also isolated from soil of infected banana crop in Sukodono District. Morphological observation showed that all bacterial isolates have similar characteristic as common bacterial wilt pathogen, Ralstonia solanacearum. In addition, detection of FliC region in all isolates confirmed that all isolates were R. solanacearum according to the presence of 400 bp of FliC DNA fragment. Moreover, two bacteriophages were obtained from this experiment (ϕRSSKD1 and ϕRSSKD2, which were able to infect all nine R. solanacearum isolates. Nucleic acid analysis showed that the nucleic acid of bacteriophages was DNA (deoxyribonucleic acid.

  13. DEVELOPMENT OF ANTIBODY TO RALSTONIA SOLANACEARUM AND ITS APPLICATION FOR DETECTION OF BACTERIAL WILT

    Directory of Open Access Journals (Sweden)

    YADI SURYADI

    2009-01-01

    Full Text Available The serological assay for the detection of bacterial wilt caused by Ralstonia solanacearum (RSwas able to provide information regarding the presence of the pathogen in plant materials. Theresearch is was aimed to develop polyclonal antibody (PAb for RS detection. Bacterial wholecells of RS isolates mixed with glutaraldehyde were used to immunize New Zealand femalewhite rabbit. The titre of antibody in culture supernatant was 1: 1024. The PAb developed froma ground nut RS isolates reacted with infected plant samples from various locations. It was ableto detect RS antigen of crude extract and pure cultures from tomato and potato plant samples4-5using dot blot ELISA; however, the minimum detectable concentration of RS antigen was 10cells/ml. The PAb obtained in this study is sensitive enough to detect RS isolates in routineserological assay

  14. A ‘Magnetic’ Gram Stain for Bacterial Detection

    OpenAIRE

    Budin, Ghyslain; Chung, Hyun Jung; Lee, Hakho; Weissleder, Ralph

    2012-01-01

    Magnetic stain. Bacteria are often classified into Gram-positive and Gram-negative strains by their visual staining properties using crystal violet (CV), a triarylmethane dye. Here we show, that bioorthogonal modification of crystal violet with transcyclooctene (TCO) can be used to render Gram-positive bacteria magnetic with magneto-nanoparticles-Tetrazine (MNP-Tz). This allows for class specific automated magnetic detection, magnetic separation or other magnetic manipulations.

  15. Detection of dichloromethane with a bioluminescent (lux) bacterial bioreporter.

    Science.gov (United States)

    Lopes, Nicholas; Hawkins, Shawn A; Jegier, Patricia; Menn, Fu-Min; Sayler, Gary S; Ripp, Steven

    2012-01-01

    The focus of this research effort was to develop an autonomous, inducible, lux-based bioluminescent bioreporter for the real-time detection of dichloromethane. Dichloromethane (DCM), also known as methylene chloride, is a volatile organic compound and one of the most commonly used halogenated solvents in the U.S., with applications ranging from grease and paint stripping to aerosol propellants and pharmaceutical tablet coatings. Predictably, it is released into the environment where it contaminates air and water resources. Due to its classification as a probable human carcinogen, hepatic toxin, and central nervous system effector, DCM must be carefully monitored and controlled. Methods for DCM detection usually rely on analytical techniques such as solid-phase microextraction (SPME) and capillary gas chromatography or photoacoustic environmental monitors, all of which require trained personnel and/or expensive equipment. To complement conventional monitoring practices, we have created a bioreporter for the self-directed detection of DCM by taking advantage of the evolutionary adaptation of bacteria to recognize and metabolize chemical agents. This bioreporter, Methylobacterium extorquens DCM( lux ), was engineered to contain a bioluminescent luxCDABE gene cassette derived from Photorhabdus luminescens fused downstream to the dcm dehalogenase operon, which causes the organism to generate visible light when exposed to DCM. We have demonstrated detection limits down to 1.0 ppm under vapor phase exposures and 0.1 ppm under liquid phase exposures with response times of 2.3 and 1.3 h, respectively, and with specificity towards DCM under relevant industrial environmental monitoring conditions.

  16. A functional gene array for detection of bacterial virulence elements

    Energy Technology Data Exchange (ETDEWEB)

    Jaing, C

    2007-11-01

    We report our development of the first of a series of microarrays designed to detect pathogens with known mechanisms of virulence and antibiotic resistance. By targeting virulence gene families as well as genes unique to specific biothreat agents, these arrays will provide important data about the pathogenic potential and drug resistance profiles of unknown organisms in environmental samples. To validate our approach, we developed a first generation array targeting genes from Escherichia coli strains K12 and CFT073, Enterococcus faecalis and Staphylococcus aureus. We determined optimal probe design parameters for microorganism detection and discrimination, measured the required target concentration, and assessed tolerance for mismatches between probe and target sequences. Mismatch tolerance is a priority for this application, due to DNA sequence variability among members of gene families. Arrays were created using the NimbleGen Maskless Array Synthesizer at Lawrence Livermore National Laboratory. Purified genomic DNA from combinations of one or more of the four target organisms, pure cultures of four related organisms, and environmental aerosol samples with spiked-in genomic DNA were hybridized to the arrays. Based on the success of this prototype, we plan to design further arrays in this series, with the goal of detecting all known virulence and antibiotic resistance gene families in a greatly expanded set of organisms.

  17. A handheld real time thermal cycler for bacterial pathogen detection.

    Science.gov (United States)

    Higgins, James A; Nasarabadi, Shanavaz; Karns, Jeffrey S; Shelton, Daniel R; Cooper, Mary; Gbakima, Aiah; Koopman, Ronald P

    2003-08-15

    The handheld advanced nucleic acid analyzer (HANAA) is a portable real time thermal cycler unit that weighs under 1 kg and uses silicon and platinum-based thermalcycler units to conduct rapid heating and cooling of plastic reaction tubes. Two light emitting diodes (LED) provide greater than 1 mW of electrical power at wavelengths of 490 nm (blue) and 525 nm (green), allowing detection of the dyes FAM and JOE/TAMRA. Results are displayed in real time as bar graphs, and up to three, 4-sample assays can be run on the charge of the 12 V portable battery pack. The HANAA was evaluated for detection of defined Escherichia coli strains, and wild-type colonies isolated from stream water, using PCR for the lac Z and Tir genes. PCR reactions using SYBR Green dye allowed detection of E. coli ATCC 11775 and E. coli O157:H7 cells in under 30 min of assay time; however, background fluorescence associated with dye binding to nonspecific PCR products was present. DNA extracted from three isolates of Bacillus anthracis Ames, linked to a bioterrorism incident in Washington DC in October 2001, were also successfully tested on the HANAA using primers for the vrrA and capA genes. Positive results were observed at 32 and 22 min of assay time, respectively. A TaqMan probe specific to the aroQ gene of Erwinia herbicola was tested on the HANAA and when 500 cells were used as template, positive results were observed after only 7 min of assay time. Background fluorescence associated with the use of the probe was negligible. The HANAA is unique in offering real time PCR in a handheld format suitable for field use; a commercial version of the instrument, offering six reaction chambers, is available as of Fall 2002. PMID:12788554

  18. Bacteriophages for detection and control of bacterial pathogens in food and food-processing environment.

    Science.gov (United States)

    Brovko, Lubov Y; Anany, Hany; Griffiths, Mansel W

    2012-01-01

    This chapter presents recent advances in bacteriophage research and their application in the area of food safety. Section 1 describes general facts on phage biology that are relevant to their application for control and detection of bacterial pathogens in food and environmental samples. Section 2 summarizes the recently acquired data on application of bacteriophages to control growth of bacterial pathogens and spoilage organisms in food and food-processing environment. Section 3 deals with application of bacteriophages for detection and identification of bacterial pathogens. Advantages of bacteriophage-based methods are presented and their shortcomings are discussed. The chapter is intended for food scientist and food product developers, and people in food inspection and health agencies with the ultimate goal to attract their attention to the new developing technology that has a tremendous potential in providing means for producing wholesome and safe food.

  19. An Accurate Method for the BDS Receiver DCB Estimation in a Regional Network

    Directory of Open Access Journals (Sweden)

    LI Xin

    2016-08-01

    Full Text Available An accurate approach for receiver differential code biases (DCB estimation is proposed with the BDS data obtained from a regional tracking network. In contrast to the conventional methods for BDS receiver DCB estimation, the proposed method does not require a complicated ionosphere model, as long as one reference station receiver DCB is known. The main idea for this method is that the ionosphere delay is highly dependent on the geometric ranges between the BDS satellite and the receiver normally. Therefore, the non-reference station receivers DCBs in this regional area can be estimated using single difference (SD with reference stations. The numerical results show that the RMS of these estimated BDS receivers DCBs errors over 30 days are about 0.3 ns. Additionally, after deduction of these estimated receivers DCBs and knowing satellites DCBs, the extractive diurnal VTEC showed a good agreement with the diurnal VTEC gained from the GIM interpolation, indicating the reliability of the estimated receivers DCBs.

  20. Phage-protease-peptide: a novel trifecta enabling multiplex detection of viable bacterial pathogens.

    Science.gov (United States)

    Alcaine, S D; Tilton, L; Serrano, M A C; Wang, M; Vachet, R W; Nugen, S R

    2015-10-01

    Bacteriophages represent rapid, readily targeted, and easily produced molecular probes for the detection of bacterial pathogens. Molecular biology techniques have allowed researchers to make significant advances in the bioengineering of bacteriophage to further improve speed and sensitivity of detection. Despite their host specificity, bacteriophages have not been meaningfully leveraged in multiplex detection of bacterial pathogens. We propose a proof-of-principal phage-based scheme to enable multiplex detection. Our scheme involves bioengineering bacteriophage to carry a gene for a specific protease, which is expressed during infection of the target cell. Upon lysis, the protease is released to cleave a reporter peptide, and the signal detected. Here we demonstrate the successful (i) modification of T7 bacteriophage to carry tobacco etch virus (TEV) protease; (ii) expression of TEV protease by Escherichia coli following infection by our modified T7, an average of 2000 units of protease per phage are produced during infection; and (iii) proof-of-principle detection of E. coli in 3 h after a primary enrichment via TEV protease activity using a fluorescent peptide and using a designed target peptide for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis (MALDI-TOF MS) analysis. This proof-of-principle can be translated to other phage-protease-peptide combinations to enable multiplex bacterial detection and readily adopted on multiple platforms, like MALDI-TOF MS or fluorescent readers, commonly found in labs.

  1. gfp-based N-acyl homoserine-lactone sensor systems for detection of bacterial communication

    DEFF Research Database (Denmark)

    Andersen, Jens Bo; Heydorn, Arne; Hentzer, Morten;

    2001-01-01

    proteins. Bacterial strains harboring this green fluorescent sensor detected a broad spectrum of AHL molecules and were capable of sensing the presence of 5 nM N-3-oxohexanoyl-L-homoserine lactone in the surroundings. In combination with epifluorescent microscopy, the sensitivity of the sensor enabled AHL...

  2. Self-assembling bacterial pores as components of nanobiosensors for the detection of single peptide molecules

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Nano-sized bacterial pores were inserted into a lipid membrane as a nanobiosensor for the detection of single peptide molecules. Due to the intrinsic properties of single-channel conductance, the transit of individual molecules through the pore can be studied. The analysis of both the blockage current and duration is able to provide specific structural information and allows the detection of specific peptides in bulk mixtures.

  3. Detection and Identification System of Bacteria and Bacterial Endotoxin Based on Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    Muhammad Elsayeh

    2016-03-01

    Full Text Available Sepsis is a global health problem that causes risk of death. In the developing world, about 60 to 80 % of death cases are caused by Sepsis. Rapid methods for detecting its causes, represent one of the major factors that may reduce Sepsis risks. Such methods can provide microbial detection and identification which is critical to determine the right treatment for the patient. Microbial and Pyrogen detection is important for quality control system to ensure the absence of pathogens and Pyrogens in the manufacturing of both medical and food products. Raman spectroscopes represent a q uick and accurate identification and detection method, for bacteria and bacterial endotoxin, which this plays an important role in delivering high quality biomedical products using the power of Raman spectroscopy. It is a rapid method for chemical structure detection that can be used in identifying and classifying bacteria and bacterial endotoxin. Such a method acts as a solution for time and cost effective quality control procedures. This work presents an automatic system based on Raman spectroscopy to detect and identify bacteria and bacterial endotoxin. It uses the frequency properties of Raman scattering through the interaction between organic materials and electromagnetic waves. The scattered intensities are measured and wave number converted into frequency, then the cepstral coefficients are extracted for both the detection and identification. The methodology depends on normalization of Fourier transformed cepstral signal to extract their classification features. Experiments’ results proved effective identification and detection of bacteria and bacterial endotoxin even with concentrations as low as 0.0003 Endotoxin unit (EU/ml and 1 Colony Forming Unit (CFU/ml using signal processing based enhancement technique.

  4. Detection of bacterial biofilms in different types of chronic otitis media.

    Science.gov (United States)

    Gu, Xingzhi; Keyoumu, Youlidusi; Long, Li; Zhang, Hua

    2014-11-01

    Biofilms are organized bacterial communities that may be homogeneous or heterogeneous. They play a significant role in the pathogenesis of chronic nasal sinusitis, chronic tonsillitis, cholesteatomas, and device-related infections. Despite this, few studies have been done that examine the presence of bacterial biofilms in tissues from patients with different types of COM or middle ear cholesteatomas. In the current study, we examined the presence of biofilms in surgical tissue specimens from humans with chronic ear infections using scanning electron microscopy (SEM). We hypothesize that bacterial biofilms present differently in patients with different types of chronic otitis media. Our results provide new insights regarding treatment of chronic otitis media. A prospective study was conducted in which middle ear tissues were obtained from 38 patients who underwent tympanoplasty and/or tympanomastoid surgery due to chronic ear infections. A total of 50 middle and mastoid tissue samples were processed for SEM analysis. In addition, 38 middle ear secretion specimens were obtained for routine bacterial culture analysis. Bacterial biofilms were present in 85 % (11 of 13) of patients with middle ear cholesteatoma, 92 % (12/13) of patients with chronic otitis suppurative media (CSOM), and 16 % of patients (2/12) with tympanic membrane perforation (TMP). Fungal biofilms were found in two cases of cholesteatoma. The positive coincidence rate between bacterial biofilms visualized by SEM and bacteria detected by culture was 82 %. Our findings suggest that bacterial biofilms are very common in CSOM and middle ear cholesteatomas. Positive bacterial cultures imply the presence of biofilm formation in CSOM and cholesteatomas. As such, our results provide new insights regarding treatment of chronic otitis media.

  5. Bacterial surface antigen-specific monoclonal antibodies used to detect beer spoilage pediococci.

    Science.gov (United States)

    Whiting, M S; Ingledew, W M; Lee, S Y; Ziola, B

    1999-08-01

    Fourteen monoclonal antibodies (Mabs) were isolated that react with surface antigens of Pediococcus beer spoilage organisms, including P. damnosus, P. pentosaceous, P. acidilactici, and unspeciated isolates. Immunoblotting, enzyme immunoassays (EIAs) of protease- and neuraminidase-treated surface antigen extracts, carbohydrate competition EIAs, and cardiolipin EIAs were used to characterize the bacterial antigens involved in Mab binding. Antigen stability in situ was tested by protease treatment or surface antigen extraction of washed bacteria. In most cases, the Mabs bind to Pediococcus surface antigens that appear to be covalently bound cell wall polymers resistant to alteration or removal from the bacterial surface. These bacterial surface antigen reactive Mabs show good potential for rapid, sensitive, and specific immunoassay detection of Pediococcus beer spoilage organisms.

  6. Color suppressed contributions to the decay modes B_{d,s} -> D_{s,d} D_{s,d}, B_{d,s} -> D_{s,d} D^*_{s,d}, and B_{d,s} -> D^*_{s,d} D^*_{s,d}

    OpenAIRE

    Eeg, Jan O.; Fajfer, Svjetlana; Prapotnik, Anita

    2005-01-01

    The amplitudes for decays of the type $B_{d,s} \\to D_{s,d} D_{s,d}$, have no factorizable contributions, while $B_{d,s} \\to D_{s,d} D^*_{s,d}$, and $B_{d,s} \\to D^*_{s,d} D^*_{s,d}$ have relatively small factorizable contributions through the annihilation mechanism. The dominant contributions to the decay amplitudes arise from chiral loop contributions and tree level amplitudes which can be obtained in terms of soft gluon emissions forming a gluon condensate. We predict that the branching rat...

  7. Evaluation of bacterial aerotaxis for its potential use in detecting the toxicity of chemicals to microorganisms.

    Science.gov (United States)

    Shitashiro, Maiko; Kato, Junichi; Fukumura, Tsuyoshi; Kuroda, Akio; Ikeda, Tsukasa; Takiguchi, Noboru; Ohtake, Hisao

    2003-02-27

    Bacterial aerotaxis (the movement of a cell toward oxygen) was evaluated for its potential use in detecting the toxicity of chemicals to microorganisms. The level of toxicity was determined by the concentration of test chemicals resulting in a 50% inhibition of aerotaxis of Pseudomonas aeruginosa PAO1 after 40 min of exposure. The aerotactic responses of P. aeruginosa were measured by using chemotaxis well chambers. Each clear acrylic chamber had a lower and upper well separated by a polycarbonate filter with a uniform pore size of 8.0 microm. To automatically detect bacterial cells that crossed the filter in response to a gradient of oxygen, P. aeruginosa PAO1 was marked with green fluorescent protein (GFP), and the GFP fluorescence intensity in the upper well was continuously monitored by using a fluorescence spectrometer. By using this technique, volatile chlorinated aliphatic compounds, including trichloroethylene (TCE), trichloroethane, and tetrachloroethylene, were found to be inhibitory to bacterial aerotaxis, suggesting their possible toxicity to microorganisms. We also examined more than 20 potential toxicants for their ability to inhibit the aerotaxis of P. aeruginosa. Based on these experimental results, we concluded that bacterial aerotaxis has potential for use as a fast and reliable indicator in assessing the toxicity of chemicals to microorganisms.

  8. Fluorescence in situ hybridization for the tissue detection of bacterial pathogens associated with porcine infections

    DEFF Research Database (Denmark)

    Jensen, Henrik Elvang; Jensen, Louise Kruse; Barington, Kristiane;

    2015-01-01

    sequences within intact cells. FISH allows direct histological localization of the bacteria in the tissue and thereby a correlation between the infection and the histopathological changes present. This chapter presents protocols for FISH identification of bacterial pathogens in fixed deparaffinized tissue......Fluorescence in situ hybridization (FISH) is an efficient technique for the identification of specific bacteria in tissue of both experimental and spontaneous infections. The method detects specific sequences of nucleic acids by hybridization of fluorescently labeled probes to complementary target...

  9. Rapid detection of malto-oligosaccharide-forming bacterial amylases by high performance anion-exchange chromatography

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Larsen, K. L.; Zimmermann, W.

    2000-01-01

    High performance anion-exchange chromatography with pulsed amperometric detection was applied for the rapid analysis of malto-oligosaccharides formed by extracellular enzyme preparations from 49 starch-degrading bacterial strains isolated from soil and compost samples. Malto-oligosaccharide-formi......-oligosaccharide-forming amylases, indicated by a predominant formation of maltohexaose from starch, were produced by enzyme preparations from four of the isolates growing at pH 7.0 and 10....

  10. Performance Analysis of BDS Satellite Orbits during Eclipse Periods: Results of Satellite Laser Ranging Validation

    Directory of Open Access Journals (Sweden)

    PENG Hanbing

    2016-06-01

    Full Text Available The performance of BeiDou satellite orbits during eclipse periods is an important part of the performance analysis of BeiDou Navigation Satellite System (BDS. Accuracy evaluation of satellite orbits in ephemeris of BDS during eclipse periods can provide support for the service performance assessment. It also helps to find possible deficiencies in the orbit modeling during eclipse periods, which may further contribute to the improvements of functional models for precise orbit determination. The effects of eclipse periods on the orbits of the three types of satellites of BDS are analyzed with the satellite laser ranging (SLR observations ranging from January 2014 to July 2015. At the same time, the orbit radial accuracy of BDS broadcast and precise ephemeris are validated. The results show that, obvious orbit accuracy decrease can be observed in both broadcast and precise ephemeris for IGSO/MEO satellites during eclipse periods (especially the yaw-maneuver periods. And orbit radial errors of IGSO/MEO satellites in broadcast ephemeris reach 1.5~2.0 m, and exceed 10.0 cm for that in precise ephemeris. Performance decrease of the GEO satellite orbit during eclipse arcs can hardly be revealed by the orbit radial residual series. During non-eclipse periods, radial accuracy of IGSO/MEO and GEO satellite orbits in broadcast ephemeris are better than 0.5 m and 0.9 m respectively. The radial accuracy of IGSO/MEO satellite orbits in precise ephemeris are better than 10.0 cm and that of the GEO satellite is about 50.0 cm with a systematic bias of 40.0 cm around.

  11. Dynamic laser speckle to detect motile bacterial response of Pseudomonas aeruginosa

    Energy Technology Data Exchange (ETDEWEB)

    Sendra, H [Laboratorio de Laser. Facultad de Ingenieria. Universidad Nacional de Mar del Plata, Juan B. Justo 4302. (7600) Mar del Plata (Argentina); Murialdo, S [Grupo de Ingenieria BioquImica. Departamento de Quimica. Facultad de Ingenieria. Universidad Nacional de Mar del Plata, Juan B. Justo 4302. (7600) Mar del Plata (Argentina); Passoni, L [Laboratorio de BioingenierIa. Facultad de Ingenieria. Universidad Nacional de Mar del Plata, Juan B. Justo 4302. (7600) Mar del Plata (Argentina)

    2007-11-15

    This proposal deals with the technique for detection of motile response of Pseudomonas aeruginosa using dynamic laser speckle or biospeckle as an alternative method. The study of bacterial displacement plays an essential role in biocatalysts processes and biodegradation. Hence, some biodegrading enzymes are benign catalytic that could be used for the production of industrially useful compounds as well as in wastewater treatments. This work presents an experimental set up and a computational process using frame sequences of dynamic laser speckle as a novel application. The objective was the detection of different levels of motility in bacteria. The encouraging results were achieved through a direct and non invasive observation method of the phenomenon.

  12. An improved haemolytic plaque assay for the detection of cells secreting antibody to bacterial antigens

    DEFF Research Database (Denmark)

    Barington, T; Heilmann, C

    1992-01-01

    Recent advances in the development of conjugate polysaccharide vaccines for human use have stimulated interest in the use of assays detecting antibody-secreting cells (AbSC) with specificity for bacterial antigens. Here we present improved haemolytic plaque-forming cell (PFC) assays detecting Ab......SC with specificity for tetanus and diphtheria toxoid as well as for Haemophilus influenzae type b and pneumococcal capsular polysaccharides. These assays were found to be less time consuming, more economical and yielded 1.9-3.4-fold higher plaque numbers than traditional Jerne-type PFC assays. In the case of anti...

  13. Application of photostable quantum dots for indirect immunofluorescent detection of specific bacterial serotypes on small marine animals

    International Nuclear Information System (INIS)

    An indirect immunofluorescence approach was developed using semiconductor quantum dot nanocrystals to label and detect a specific bacterial serotype of the bacterial human pathogen Vibrio parahaemolyticus, attached to small marine animals (i.e. benthic harpacticoid copepods), which are suspected pathogen carriers. This photostable labeling method using nanotechnology will potentially allow specific serotypes of other bacterial pathogens to be detected with high sensitivity in a range of systems, and can be easily applied for sensitive detection to other Vibrio species such as Vibrio cholerae

  14. Application of photostable quantum dots for indirect immunofluorescent detection of specific bacterial serotypes on small marine animals

    Science.gov (United States)

    Decho, Alan W.; Beckman, Erin M.; Chandler, G. Thomas; Kawaguchi, Tomohiro

    2008-06-01

    An indirect immunofluorescence approach was developed using semiconductor quantum dot nanocrystals to label and detect a specific bacterial serotype of the bacterial human pathogen Vibrio parahaemolyticus, attached to small marine animals (i.e. benthic harpacticoid copepods), which are suspected pathogen carriers. This photostable labeling method using nanotechnology will potentially allow specific serotypes of other bacterial pathogens to be detected with high sensitivity in a range of systems, and can be easily applied for sensitive detection to other Vibrio species such as Vibrio cholerae.

  15. A Comparison between Transcriptome Sequencing and 16S Metagenomics for Detection of Bacterial Pathogens in Wildlife.

    Directory of Open Access Journals (Sweden)

    Maria Razzauti

    Full Text Available Rodents are major reservoirs of pathogens responsible for numerous zoonotic diseases in humans and livestock. Assessing their microbial diversity at both the individual and population level is crucial for monitoring endemic infections and revealing microbial association patterns within reservoirs. Recently, NGS approaches have been employed to characterize microbial communities of different ecosystems. Yet, their relative efficacy has not been assessed. Here, we compared two NGS approaches, RNA-Sequencing (RNA-Seq and 16S-metagenomics, assessing their ability to survey neglected zoonotic bacteria in rodent populations.We first extracted nucleic acids from the spleens of 190 voles collected in France. RNA extracts were pooled, randomly retro-transcribed, then RNA-Seq was performed using HiSeq. Assembled bacterial sequences were assigned to the closest taxon registered in GenBank. DNA extracts were analyzed via a 16S-metagenomics approach using two sequencers: the 454 GS-FLX and the MiSeq. The V4 region of the gene coding for 16S rRNA was amplified for each sample using barcoded universal primers. Amplicons were multiplexed and processed on the distinct sequencers. The resulting datasets were de-multiplexed, and each read was processed through a pipeline to be taxonomically classified using the Ribosomal Database Project. Altogether, 45 pathogenic bacterial genera were detected. The bacteria identified by RNA-Seq were comparable to those detected by 16S-metagenomics approach processed with MiSeq (16S-MiSeq. In contrast, 21 of these pathogens went unnoticed when the 16S-metagenomics approach was processed via 454-pyrosequencing (16S-454. In addition, the 16S-metagenomics approaches revealed a high level of coinfection in bank voles.We concluded that RNA-Seq and 16S-MiSeq are equally sensitive in detecting bacteria. Although only the 16S-MiSeq method enabled identification of bacteria in each individual reservoir, with subsequent derivation of

  16. Investigation of polymerase chain reaction assays to improve detection of bacterial involvement in bovine respiratory disease.

    Science.gov (United States)

    Bell, Colin J; Blackburn, Paul; Elliott, Mark; Patterson, Tony I A P; Ellison, Sean; Lahuerta-Marin, Angela; Ball, Hywel J

    2014-09-01

    Bovine respiratory disease (BRD) causes severe economic losses to the cattle farming industry worldwide. The major bacterial organisms contributing to the BRD complex are Mannheimia haemolytica, Histophilus somni, Mycoplasma bovis, Pasteurella multocida, and Trueperella pyogenes. The postmortem detection of these organisms in pneumonic lung tissue is generally conducted using standard culture-based techniques where the presence of therapeutic antibiotics in the tissue can inhibit bacterial isolation. In the current study, conventional and real-time polymerase chain reaction (PCR) assays were used to assess the prevalence of these 5 organisms in grossly pneumonic lung samples from 150 animals submitted for postmortem examination, and the results were compared with those obtained using culture techniques. Mannheimia haemolytica was detected in 51 cases (34%) by PCR and in 33 cases (22%) by culture, H. somni was detected in 35 cases (23.3%) by PCR and in 6 cases (4%) by culture, Myc. bovis was detected in 53 cases (35.3%) by PCR and in 29 cases (19.3%) by culture, P. multocida was detected in 50 cases (33.3%) by PCR and in 31 cases (20.7%) by culture, and T. pyogenes was detected in 42 cases (28%) by PCR and in 31 cases (20.7%) by culture, with all differences being statistically significant. The PCR assays indicated positive results for 111 cases (74%) whereas 82 cases (54.6%) were culture positive. The PCR assays have demonstrated a significantly higher rate of detection of all 5 organisms in cases of pneumonia in cattle in Northern Ireland than was detected by current standard procedures.

  17. Evaluation of the efficiency of biofield diagnostic system in breast cancer detection using clinical study results and classifiers.

    Science.gov (United States)

    Subbhuraam, Vinitha Sree; Ng, E Y K; Kaw, G; Acharya U, Rajendra; Chong, B K

    2012-02-01

    The division of breast cancer cells results in regions of electrical depolarisation within the breast. These regions extend to the skin surface from where diagnostic information can be obtained through measurements of the skin surface electropotentials using sensors. This technique is used by the Biofield Diagnostic System (BDS) to detect the presence of malignancy. This paper evaluates the efficiency of BDS in breast cancer detection and also evaluates the use of classifiers for improving the accuracy of BDS. 182 women scheduled for either mammography or ultrasound or both tests participated in the BDS clinical study conducted at Tan Tock Seng hospital, Singapore. Using the BDS index obtained from the BDS examination and the level of suspicion score obtained from mammography/ultrasound results, the final BDS result was deciphered. BDS demonstrated high values for sensitivity (96.23%), specificity (93.80%), and accuracy (94.51%). Also, we have studied the performance of five supervised learning based classifiers (back propagation network, probabilistic neural network, linear discriminant analysis, support vector machines, and a fuzzy classifier), by feeding selected features from the collected dataset. The clinical study results show that BDS can help physicians to differentiate benign and malignant breast lesions, and thereby, aid in making better biopsy recommendations.

  18. Evaluation of the efficiency of biofield diagnostic system in breast cancer detection using clinical study results and classifiers.

    Science.gov (United States)

    Subbhuraam, Vinitha Sree; Ng, E Y K; Kaw, G; Acharya U, Rajendra; Chong, B K

    2012-02-01

    The division of breast cancer cells results in regions of electrical depolarisation within the breast. These regions extend to the skin surface from where diagnostic information can be obtained through measurements of the skin surface electropotentials using sensors. This technique is used by the Biofield Diagnostic System (BDS) to detect the presence of malignancy. This paper evaluates the efficiency of BDS in breast cancer detection and also evaluates the use of classifiers for improving the accuracy of BDS. 182 women scheduled for either mammography or ultrasound or both tests participated in the BDS clinical study conducted at Tan Tock Seng hospital, Singapore. Using the BDS index obtained from the BDS examination and the level of suspicion score obtained from mammography/ultrasound results, the final BDS result was deciphered. BDS demonstrated high values for sensitivity (96.23%), specificity (93.80%), and accuracy (94.51%). Also, we have studied the performance of five supervised learning based classifiers (back propagation network, probabilistic neural network, linear discriminant analysis, support vector machines, and a fuzzy classifier), by feeding selected features from the collected dataset. The clinical study results show that BDS can help physicians to differentiate benign and malignant breast lesions, and thereby, aid in making better biopsy recommendations. PMID:20703753

  19. Near-infrared spectroscopy for the detection and quantification of bacterial contaminations in pharmaceutical products.

    Science.gov (United States)

    Quintelas, Cristina; Mesquita, Daniela P; Lopes, João A; Ferreira, Eugénio C; Sousa, Clara

    2015-08-15

    Accurate detection and quantification of microbiological contaminations remains an issue mainly due the lack of rapid and precise analytical techniques. Standard methods are expensive and time-consuming being associated to high economic losses and public health threats. In the context of pharmaceutical industry, the development of fast analytical techniques able to overcome these limitations is crucial and spectroscopic techniques might constitute a reliable alternative. In this work we proved the ability of Fourier transform near infrared spectroscopy (FT-NIRS) to detect and quantify bacteria (Bacillus subtilis, Escherichia coli, Pseudomonas fluorescens, Salmonella enterica, Staphylococcus epidermidis) from 10 to 10(8) CFUs/mL in sterile saline solutions (NaCl 0.9%). Partial least squares discriminant analysis (PLSDA) models showed that FT-NIRS was able to discriminate between sterile and contaminated solutions for all bacteria as well as to identify the contaminant bacteria. Partial least squares (PLS) models allowed bacterial quantification with limits of detection ranging from 5.1 to 9 CFU/mL for E. coli and B. subtilis, respectively. This methodology was successfully validated in three pharmaceutical preparations (contact lens solution, cough syrup and topic anti-inflammatory solution) proving that this technique possess a high potential to be routinely used for the detection and quantification of bacterial contaminations. PMID:26151105

  20. Rapid Methods for the Detection of Foodborne Bacterial Pathogens: Principles, Applications, Advantages and Limitations

    Directory of Open Access Journals (Sweden)

    Law eJodi Woan-Fei

    2015-01-01

    Full Text Available The incidence of foodborne diseases has increased over the years and resulted in major public health problem globally. Foodborne pathogens can be found in various foods and it is important to detect foodborne pathogens to provide safe food supply and to prevent foodborne diseases. The conventional methods used to detect foodborne pathogen are time consuming and laborious. Hence, a variety of methods have been developed for rapid detection of foodborne pathogens as it is required in many food analyses. Rapid detection methods can be categorized into nucleic acid-based, biosensor-based and immunological-based methods. This review emphasizes on the principles and application of recent rapid methods for the detection of foodborne bacterial pathogens. Detection methods included are simple polymerase chain reaction (PCR, multiplex PCR, real-time PCR, nucleic acid sequence-based amplification (NASBA, loop-mediated isothermal amplification (LAMP and oligonucleotide DNA microarray which classified as nucleic acid-based methods; optical, electrochemical and mass-based biosensors which classified as biosensor-based methods; enzyme-linked immunosorbent assay (ELISA and lateral flow immunoassay which classified as immunological-based methods. In general, rapid detection methods are generally time-efficient, sensitive, specific and labor-saving. The developments of rapid detection methods are vital in prevention and treatment of foodborne diseases.

  1. Scalable DNA-Based Magnetic Nanoparticle Agglutination Assay for Bacterial Detection in Patient Samples

    DEFF Research Database (Denmark)

    Mezger, Anja; Fock, Jeppe; Antunes, Paula Soares Martins;

    2015-01-01

    We demonstrate a nanoparticle-based assay for the detection of bacteria causing urinary tract infections in patient samples with a total assay time of 4 h. This time is significantly shorter than the current gold standard, plate culture, which can take several days depending on the pathogen....... The assay is based on padlock probe recognition followed by two cycles of rolling circle amplification (RCA) to form DNA coils corresponding to the target bacterial DNA. The readout of the RCA products is based on optomagnetic measurements of the specific agglutination of DNA-bound magnetic nanoparticles...... (MNPs) using low-cost optoelectronic components from Blu-ray drives. We implement a detection approach, which relies on the monomerization of the RCA products, the use of the monomers to link and agglutinate two populations of MNPs functionalized with universal nontarget specific detection probes...

  2. A simple bacterial turbidimetric method for detection of some radurized foods

    International Nuclear Information System (INIS)

    A simple and quick method for detection of irradiated food is proposed. The method is based on the principle of microbial contribution to the development of turbidity in a clear medium. It employs measurement of absorbance at 600 nm of the medium after the test commodity has been suspended and shaken in it for a fixed interval. The differences in the bacterial turbidity from irradiated and nonirradiated samples are quite marked so as to allow identification of the irradiated foods like fish, lamb meat, chicken and mushroom. (author)

  3. Disposable bioluminescence-based biosensor for detection of bacterial count in food.

    Science.gov (United States)

    Luo, Jinping; Liu, Xiaohong; Tian, Qing; Yue, Weiwei; Zeng, Jing; Chen, Guangquan; Cai, Xinxia

    2009-11-01

    A biosensor for rapid detection of bacterial count based on adenosine 5'-triphosphate (ATP) bioluminescence has been developed. The biosensor is composed of a key sensitive element and a photomultiplier tube used as a detector element. The disposable sensitive element consists of a sampler, a cartridge where intracellular ATP is chemically extracted from bacteria, and a microtube where the extracted ATP reacts with the luciferin-luciferase reagent to produce bioluminescence. The bioluminescence signal is transformed into relevant electrical signal by the detector and further measured with a homemade luminometer. Parameters affecting the amount of the extracted ATP, including the types of ATP extractants, the concentrations of ATP extractant, and the relevant neutralizing reagent, were optimized. Under the optimal experimental conditions, the biosensor showed a linear response to standard bacteria in a concentration range from 10(3) to 10(8) colony-forming units (CFU) per milliliter with a correlation coefficient of 0.925 (n=22) within 5min. Moreover, the bacterial count of real food samples obtained by the biosensor correlated well with those by the conventional plate count method. The proposed biosensor, with characteristics of low cost, easy operation, and fast response, provides potential application to rapid evaluation of bacterial contamination in the food industry, environment monitoring, and other fields.

  4. Development of a bacterial bioassay for atrazine and cyanuric acid detection

    Directory of Open Access Journals (Sweden)

    Anna eHUA

    2015-03-01

    Full Text Available The s-triazine herbicides are compounds which can disseminate into soils and water. Due to their toxic effects on living organisms, their concentrations in drinking water are legislated by WHO recommendations. Here we have developed for the first time, to the best of our knowledge, an alternative method for physicochemical quantification using two bioluminescent bacterial biosensors: E. coli SM003 for cyanuric acid detection and E. coli SM004 for both atrazine and cyanuric acid detection. The concentration of cyanuric acid detection for E. coli SM003 ranges from 7.83 µM to 2.89 mM, and for E. coli SM004 ranges from 0.22 µM to 15 µM. Moreover, atrazine detection by E. coli SM004 ranges from 1.08 µM to 15 µM. According to WHO recommendations, the cyanuric acid detection range is sensitive enough to discriminate between polluted and drinking water. Nevertheless, the detection of atrazine by E. coli SM004 is only applicable for high concentrations of contaminants.

  5. Atypical sensors for direct and rapid neuronal detection of bacterial pathogens.

    Science.gov (United States)

    Lim, Ji Yeon; Choi, Seung-In; Choi, Geunyeol; Hwang, Sun Wook

    2016-03-09

    Bacterial infection can threaten the normal biological functions of a host, often leading to a disease. Hosts have developed complex immune systems to cope with the danger. Preceding the elimination of pathogens, selective recognition of the non-self invaders is necessary. At the forefront of the body's defenses are the innate immune cells, which are equipped with particular sensor molecules that can detect common exterior patterns of invading pathogens and their secreting toxins as well as with phagocytic machinery. Inflammatory mediators and cytokines released from these innate immune cells and infected tissues can boost the inflammatory cascade and further recruit adaptive immune cells to maximize the elimination and resolution. The nervous system also seems to interact with this process, mostly known to be affected by the inflammatory mediators through the binding of neuronal receptors, consequently activating neural circuits that tune the local and systemic inflammatory states. Recent research has suggested new contact points: direct interactions of sensory neurons with pathogens. Latest findings demonstrated that the sensory neurons not only share pattern recognition mechanisms with innate immune cells, but also utilize endogenous and exogenous electrogenic components for bacterial pathogen detection, by which the electrical firing prompts faster information flow than what could be achieved when the immune system is solely involved. As a result, rapid pain generation and active accommodation of the immune status occur. Here we introduced the sensory neuron-specific detector molecules for directly responding to bacterial pathogens and their signaling mechanisms. We also discussed extended issues that need to be explored in the future.

  6. Preparation of miniantibodies to Azospirillum brasilense Sp245 surface antigens and their use for bacterial detection.

    Science.gov (United States)

    Dykman, Lev A; Staroverov, Sergei A; Guliy, Olga I; Ignatov, Oleg V; Fomin, Alexander S; Vidyasheva, Irina V; Karavaeva, Olga A; Bunin, Viktor D; Burygin, Gennady L

    2012-01-01

    This article reports the first preparation of miniantibodies to Azospirillum brasilense Sp245 surface antigens by using a combinatorial phage library of sheep antibodies. The prepared phage antibodies were used for the first time for lipopolysaccharide and flagellin detection by dot assay, electro-optical analysis of cell suspensions, and transmission electron microscopy. Interaction of A. brasilense Sp245 with antilipopolysaccharide and antiflagellin phage-displayed miniantibodies caused the magnitude of the electro-optical signal to change considerably. The electro-optical results were in good agreement with the electron microscopic data. This is the first reported possibility of employing phage-displayed miniantibodies in bacterial detection aided by electro-optical analysis of cell suspensions.

  7. Bacterial and viral pathogens detected in sea turtles stranded along the coast of Tuscany, Italy.

    Science.gov (United States)

    Fichi, G; Cardeti, G; Cersini, A; Mancusi, C; Guarducci, M; Di Guardo, G; Terracciano, G

    2016-03-15

    During 2014, six loggerhead turtles, Caretta caretta and one green turtle, Chelonia mydas, found stranded on the Tuscany coast of Italy, were examined for the presence of specific bacterial and viral agents, along with their role as carriers of fish and human pathogens. Thirteen different species of bacteria, 10 Gram negative and 3 Gram positive, were identified. Among them, two strains of Vibrio parahaemolyticus and one strain of Lactococcus garviae were recovered and confirmed by specific PCR protocols. No trh and tdh genes were detected in V. parahaemolyticus. The first isolation of L. garviae and the first detection of Betanodavirus in sea turtles indicate the possibility for sea turtles to act as carriers of fish pathogens. Furthermore, the isolation of two strains of V. parahaemolyticus highlights the possible role of these animals in human pathogens' diffusion.

  8. A broadband capacitive sensing method for label-free bacterial LPS detection.

    Science.gov (United States)

    Rydosz, Artur; Brzozowska, Ewa; Górska, Sabina; Wincza, Krzysztof; Gamian, Andrzej; Gruszczynski, Slawomir

    2016-01-15

    In this paper, the authors present a new type of highly sensitive label-free microwave sensor in a form of interdigital capacitor coated with T4 bacteriophage gp37 adhesin. The adhesin binds Escherichia coli B (E. coli B) by precise recognizing its bacterial host lipopolysaccharide (LPS). The C-terminal part of the adhesin consists of the receptor-binding amino acid residues which are involved in a specific interaction with two terminal glucose residues of the bacterial LPS. The change of the sensors' capacitance and conductance as a subject to LPS presence is an indicator of the detection. The measurements in the frequency range of 0-3GHz utilizing vector network analyzer have been carried out at different concentrations to verify experimentally the proposed method. The measured capacitance change between the reference and the biofunctionalized sensor equals 15% in the entire frequency range and the measured conductance change exceeds 19%. The changes of both parameters can be used as good indicators of the LPS detection. The selectivity has been confirmed by the ELISA experiments and tested by sensor measurements with lipopolysaccharide (LPS) from E. coli B, E. coli 056, E. coli 0111, Pseudomonas aeruginosa NBRC 13743 and Hafnia alvei 1185. PMID:26339930

  9. Real-time Bacterial Detection by Single Cell Based Sensors UsingSynchrotron FTIR Spectromicroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Veiseh, Mandana; Veiseh, Omid; Martin, Michael C.; Bertozzi,Carolyn; Zhang, Miqin

    2005-08-10

    Microarrays of single macrophage cell based sensors weredeveloped and demonstrated for real time bacterium detection bysynchrotron FTIR microscopy. The cells were patterned on gold-SiO2substrates via a surface engineering technique by which the goldelectrodes were immobilized with fibronectin to mediate cell adhesion andthe silicon oxide background were passivated with PEG to resist proteinadsorption and cell adhesion. Cellular morphology and IR spectra ofsingle, double, and triple cells on gold electrodes exposed tolipopolysaccharide (LPS) of different concentrations were compared toreveal the detection capabilities of these biosensors. The single-cellbased sensors were found to generate the most significant IR wave numbervariation and thus provide the highest detection sensitivity. Changes inmorphology and IR spectrum for single cells exposed to LPS were found tobe time- and concentration-dependent and correlated with each other verywell. FTIR spectra from single cell arrays of gold electrodes withsurface area of 25 mu-m2, 100 mu-m2, and 400 mu-m2 were acquired usingboth synchrotron and conventional FTIR spectromicroscopes to study thesensitivity of detection. The results indicated that the developedsingle-cell platform can be used with conventional FTIRspectromicroscopy. This technique provides real-time, label-free, andrapid bacterial detection, and may allow for statistic and highthroughput analyses, and portability.

  10. Data mining approach to evaluating the use of skin surface electropotentials for breast cancer detection.

    Science.gov (United States)

    Sree, S Vinitha; Ng, E Y K; Acharya, U Rajendra

    2010-02-01

    The Biofield Diagnostic System (BDS) uses a score formed with measured skin surface electropotentials and a prior Level Of Suspicion (LOS) value (predicted by the physician based on the patient's ultrasound or mammography results) to calculate a revised Post-BDS LOS to indicate the presence of breast cancer. The demographic details, BDS test results, and the recorded electropotential values form a potentially useful dataset, which can be further explored with data mining tools to extract important information that can be used to improve the current predictive accuracy of the device. According to the proposed data mining framework, the BDS dataset with 291 cases was first pre-processed to remove outliers and then used to select relevant and informative features for classifier development and finally to evaluate the capability of the built classifiers in detecting the presence of the disease. Two popular feature selection techniques, namely, the filter and wrapper methods, were used in parallel for feature selection. A few statistical inference based classifiers and neural networks were used for classification. The proposed technique significantly improved the BDS prediction accuracy. Also, the use of prior LOS and, hence, the Post-BDS LOS, associates a mild subjective interpretation to the current prediction methodology used by BDS. However, the feature subset selected in our analysis that gave the best accuracy did not use either of these features. This result indicates the possibility of using BDS as a better objective assessment tool for breast cancer detection.

  11. Data mining approach to evaluating the use of skin surface electropotentials for breast cancer detection.

    Science.gov (United States)

    Sree, S Vinitha; Ng, E Y K; Acharya, U Rajendra

    2010-02-01

    The Biofield Diagnostic System (BDS) uses a score formed with measured skin surface electropotentials and a prior Level Of Suspicion (LOS) value (predicted by the physician based on the patient's ultrasound or mammography results) to calculate a revised Post-BDS LOS to indicate the presence of breast cancer. The demographic details, BDS test results, and the recorded electropotential values form a potentially useful dataset, which can be further explored with data mining tools to extract important information that can be used to improve the current predictive accuracy of the device. According to the proposed data mining framework, the BDS dataset with 291 cases was first pre-processed to remove outliers and then used to select relevant and informative features for classifier development and finally to evaluate the capability of the built classifiers in detecting the presence of the disease. Two popular feature selection techniques, namely, the filter and wrapper methods, were used in parallel for feature selection. A few statistical inference based classifiers and neural networks were used for classification. The proposed technique significantly improved the BDS prediction accuracy. Also, the use of prior LOS and, hence, the Post-BDS LOS, associates a mild subjective interpretation to the current prediction methodology used by BDS. However, the feature subset selected in our analysis that gave the best accuracy did not use either of these features. This result indicates the possibility of using BDS as a better objective assessment tool for breast cancer detection. PMID:20082535

  12. Análisis de las deficiencias del test BDS en series temporales univariantes

    Directory of Open Access Journals (Sweden)

    Pedro A. Pérez Pascual

    2002-01-01

    Full Text Available El test BDS de Brock, Dechert y Scheinkman es un test asintótico que proporciona una herramienta no paramétrica para contrastar la hipótesis nula de series i.i.d., con potencia, en teoría, sobre todas las alternativas restantes (lineales y no lineales, estocásticas y deterministas. Recientemente una versión del BDS ha sido implementada en el E-views, motivo por el que la herramienta ganará difusión dentro del análisis econométrico. Desafortunadamente, con anterioridad a esta reciente implementación y aún en la actualidad, se han observado ciertas deficiencias en la potencia y tamaño del test para muestras finitas; la sensibilidad del test ante ciertos parámetros del mismo y en el modo de evaluar los resultados; etc. Estas deficiencias, y otras nuevas, son expuestas y analizadas ofreciendo explicaciones cuando esto es posible.

  13. Evaluation of vaginal pH for detection of bacterial vaginosis

    Directory of Open Access Journals (Sweden)

    R Hemalatha

    2013-01-01

    Full Text Available Background & objectives : Bacterial vaginosis (BV is highly prevalent among women in reproductive age group. Little information exists on routine vaginal p H measurement in women with BV. We undertook this study to assess the utility of vaginal p H determination for initial evaluation of bacterial vaginosis. Methods : In this cross-sectional study vaginal swabs were collected from women with complaints of white discharge, back ache and pain abdomen attending a government hospital and a community health clinic, and subjected to vaginal p H determination, Gram stain, wet mount and whiff test. Nugent score and Amsel criteria were used for BV confirmation. Results : Of the 270 women included in the analysis, 154 had BV based on Nugents′ score. The mean vaginal p H in women with BV measured by p H strips and p H glove was 5 and 4.9, respectively. The vaginal p H was significantly higher in women with BV. Vaginal discharge was prevalent in 84.8 per cent women, however, only 56.8 per cent of these actually had BV by Nugent score (NS. Presence of clue cells and positive whiff test were significant for BV. Vaginal p H >4.5 by p H strips and p H Glove had a sensitivity of 72 and 79 per cent and specificity of 60 and 53 per cent, respectively to detect BV. Among the combination criteria, clue cells and glove p H >4.5 had highest sensitivity and specificity to detect BV. Interpretation & conclusions : Vaginal p H determination is relatively sensitive, but less specific in detecting women with BV. Inclusion of whiff test along with p H test reduced the sensitivity, but improved specificity. Both, the p H strip and p H glove are equally suitable for screening women with BV on outpatient basis.

  14. Optimisation of the detection of bacterial proteases using adsorbed immunoglobulins as universal substrates.

    Science.gov (United States)

    Abuknesha, Ram A; Jeganathan, Fiona; Wildeboer, Dirk; Price, Robert G

    2010-06-15

    Bacterial proteases, Type XXIV from Bacillus licheniformens and Type XIV from Streptomyces griseus, were used to investigate the utility and optimisation of a solid phase assay for proteases, using immunoglobulin proteins as substrates. Immunoglobulins IgA and IgG were adsorbed on to surfaces of ELISA plates and exposed to various levels of the bacterial proteases which led to digestion and desorption of proportional amounts of the immunoglobulins. The assay signal was developed by measuring the remaining proteins on the polystyrene surface with appropriate enzyme-labelled anti-immunoglobulin reagents. The assay was fully optimised in terms of substrate levels employing ELISA techniques to titrate levels of adsorbed substrates and protease analytes. The critical factor which influences assay sensitivity was found to be the substrate concentration, the levels of adsorbed immunoglobulins. The estimated detection limits for protease XXIV and XIV were 10micro units/test and 9micro units/test using IgA as a substrate. EC(50) values were calculated as 213 and 48micro units/test for each protease respectively. Using IgG as a substrate, the estimated detection limits were 104micro units/test for protease XXIV and 9micro units/test for protease XIV. EC(50) values were calculated at 529micro units/test and 28micro units/test for protease XXIV and XIV respectively. The solid phase protease assay required no modification of the substrates and the adsorption step is merely simple addition of immunoglobulins to ELISA plates. Adsorption of the immunoglobulins to polystyrene enabled straightforward separation of reaction mixtures prior to development of assay signal. The assay exploits the advantages of the technical facilities of ELISA technology and commercially available reagents enabling the detection and measurement of a wide range of proteases. However, the key issue was found to be that in order to achieve the potential performance of the simple assay, optimisation of the

  15. Label- and amplification-free electrochemical detection of bacterial ribosomal RNA.

    Science.gov (United States)

    Henihan, Grace; Schulze, Holger; Corrigan, Damion K; Giraud, Gerard; Terry, Jonathan G; Hardie, Alison; Campbell, Colin J; Walton, Anthony J; Crain, Jason; Pethig, Ronald; Templeton, Kate E; Mount, Andrew R; Bachmann, Till T

    2016-07-15

    Current approaches to molecular diagnostics rely heavily on PCR amplification and optical detection methods which have restrictions when applied to point of care (POC) applications. Herein we describe the development of a label-free and amplification-free method of pathogen detection applied to Escherichia coli which overcomes the bottleneck of complex sample preparation and has the potential to be implemented as a rapid, cost effective test suitable for point of care use. Ribosomal RNA is naturally amplified in bacterial cells, which makes it a promising target for sensitive detection without the necessity for prior in vitro amplification. Using fluorescent microarray methods with rRNA targets from a range of pathogens, an optimal probe was selected from a pool of probe candidates identified in silico. The specificity of probes was investigated on DNA microarray using fluorescently labeled 16S rRNA target. The probe yielding highest specificity performance was evaluated in terms of sensitivity and a LOD of 20 pM was achieved on fluorescent glass microarray. This probe was transferred to an EIS end point format and specificity which correlated to microarray data was demonstrated. Excellent sensitivity was facilitated by the use of uncharged PNA probes and large 16S rRNA target and investigations resulted in an LOD of 50 pM. An alternative kinetic EIS assay format was demonstrated with which rRNA could be detected in a species specific manner within 10-40min at room temperature without wash steps. PMID:27016627

  16. Single-cell-based sensors and synchrotron FTIR spectroscopy: a hybrid system towards bacterial detection.

    Science.gov (United States)

    Veiseh, Mandana; Veiseh, Omid; Martin, Michael C; Bertozzi, Carolyn; Zhang, Miqin

    2007-09-30

    Microarrays of single macrophage cell-based sensors were developed and demonstrated for potential real-time bacterium detection by synchrotron FTIR microscopy. The cells were patterned on gold electrodes of silicon oxide substrates by a surface engineering technique, in which the gold electrodes were immobilized with fibronectin to mediate cell adhesion and the silicon oxide background was passivated with polyethylene glycol (PEG) to resist protein adsorption and cell adhesion. Cell morphology and IR spectra of single, double, and triple cells on gold electrodes exposed to lipopolysaccharide (LPS) of different concentrations were compared to reveal the detection capability of this cell-based sensing platform. The single-cell-based system was found to generate the most significant and consistent IR spectrum shifts upon exposure to LPS, thus providing the highest detection sensitivity. Changes in cell morphology and IR shifts upon cell exposure to LPS were found to be dependent on the LPS concentration and exposure time, which established a method for the identification of LPS concentration and infected cell population. Possibility of using this single-cell system with conventional IR spectroscopy as well as its limitation was investigated by comparing IR spectra of single-cell arrays with gold electrode surface areas of 25, 100, and 400 microm2 using both synchrotron and conventional FTIR spectromicroscopes. This cell-based platform may potentially provide real-time, label-free, and rapid bacterial detection, and allow for high-throughput statistical analyses, and portability. PMID:17560777

  17. Label- and amplification-free electrochemical detection of bacterial ribosomal RNA.

    Science.gov (United States)

    Henihan, Grace; Schulze, Holger; Corrigan, Damion K; Giraud, Gerard; Terry, Jonathan G; Hardie, Alison; Campbell, Colin J; Walton, Anthony J; Crain, Jason; Pethig, Ronald; Templeton, Kate E; Mount, Andrew R; Bachmann, Till T

    2016-07-15

    Current approaches to molecular diagnostics rely heavily on PCR amplification and optical detection methods which have restrictions when applied to point of care (POC) applications. Herein we describe the development of a label-free and amplification-free method of pathogen detection applied to Escherichia coli which overcomes the bottleneck of complex sample preparation and has the potential to be implemented as a rapid, cost effective test suitable for point of care use. Ribosomal RNA is naturally amplified in bacterial cells, which makes it a promising target for sensitive detection without the necessity for prior in vitro amplification. Using fluorescent microarray methods with rRNA targets from a range of pathogens, an optimal probe was selected from a pool of probe candidates identified in silico. The specificity of probes was investigated on DNA microarray using fluorescently labeled 16S rRNA target. The probe yielding highest specificity performance was evaluated in terms of sensitivity and a LOD of 20 pM was achieved on fluorescent glass microarray. This probe was transferred to an EIS end point format and specificity which correlated to microarray data was demonstrated. Excellent sensitivity was facilitated by the use of uncharged PNA probes and large 16S rRNA target and investigations resulted in an LOD of 50 pM. An alternative kinetic EIS assay format was demonstrated with which rRNA could be detected in a species specific manner within 10-40min at room temperature without wash steps.

  18. Modular microfluidic system fabricated in thermoplastics for the strain-specific detection of bacterial pathogens†

    Science.gov (United States)

    Chen, Yi-Wen; Wang, Hong; Hupert, Mateusz; Witek, Makgorzata; Dharmasiri, Udara; Pingle, Maneesh R.; Barany, Francis

    2015-01-01

    The recent outbreaks of a lethal E. coli strain in Germany have aroused renewed interest in developing rapid, specific and accurate systems for detecting and characterizing bacterial pathogens in suspected contaminated food and/or water supplies. To address this need, we have designed, fabricated and tested an integrated modular-based microfluidic system and the accompanying assay for the strain-specific identification of bacterial pathogens. The system can carry out the entire molecular processing pipeline in a single disposable fluidic cartridge and detect single nucleotide variations in selected genes to allow for the identification of the bacterial species, even its strain with high specificity. The unique aspect of this fluidic cartridge is its modular format with task-specific modules interconnected to a fluidic motherboard to permit the selection of the target material. In addition, to minimize the amount of finishing steps for assembling the fluidic cartridge, many of the functional components were produced during the polymer molding step used to create the fluidic network. The operation of the cartridge was provided by electronic, mechanical, optical and hydraulic controls located off-chip and packaged into a small footprint instrument (1 ft3). The fluidic cartridge was capable of performing cell enrichment, cell lysis, solid-phase extraction (SPE) of genomic DNA, continuous flow (CF) PCR, CF ligase detection reaction (LDR) and universal DNA array readout. The cartridge was comprised of modules situated on a fluidic motherboard; the motherboard was made from polycarbonate, PC, and used for cell lysis, SPE, CF PCR and CF LDR. The modules were task-specific units and performed universal zip-code array readout or affinity enrichment of the target cells with both made from poly(methylmethacrylate), PMMA. Two genes, uidA and sipB/C, were used to discriminate between E. coli and Salmonella, and evaluated as a model system. Results showed that the fluidic system

  19. Modular microfluidic system fabricated in thermoplastics for the strain-specific detection of bacterial pathogens.

    Science.gov (United States)

    Chen, Yi-Wen; Wang, Hong; Hupert, Mateusz; Witek, Makgorzata; Dharmasiri, Udara; Pingle, Maneesh R; Barany, Francis; Soper, Steven A

    2012-09-21

    The recent outbreaks of a lethal E. coli strain in Germany have aroused renewed interest in developing rapid, specific and accurate systems for detecting and characterizing bacterial pathogens in suspected contaminated food and/or water supplies. To address this need, we have designed, fabricated and tested an integrated modular-based microfluidic system and the accompanying assay for the strain-specific identification of bacterial pathogens. The system can carry out the entire molecular processing pipeline in a single disposable fluidic cartridge and detect single nucleotide variations in selected genes to allow for the identification of the bacterial species, even its strain with high specificity. The unique aspect of this fluidic cartridge is its modular format with task-specific modules interconnected to a fluidic motherboard to permit the selection of the target material. In addition, to minimize the amount of finishing steps for assembling the fluidic cartridge, many of the functional components were produced during the polymer molding step used to create the fluidic network. The operation of the cartridge was provided by electronic, mechanical, optical and hydraulic controls located off-chip and packaged into a small footprint instrument (1 ft(3)). The fluidic cartridge was capable of performing cell enrichment, cell lysis, solid-phase extraction (SPE) of genomic DNA, continuous flow (CF) PCR, CF ligase detection reaction (LDR) and universal DNA array readout. The cartridge was comprised of modules situated on a fluidic motherboard; the motherboard was made from polycarbonate, PC, and used for cell lysis, SPE, CF PCR and CF LDR. The modules were task-specific units and performed universal zip-code array readout or affinity enrichment of the target cells with both made from poly(methylmethacrylate), PMMA. Two genes, uidA and sipB/C, were used to discriminate between E. coli and Salmonella, and evaluated as a model system. Results showed that the fluidic

  20. Modular microfluidic system fabricated in thermoplastics for the strain-specific detection of bacterial pathogens.

    Science.gov (United States)

    Chen, Yi-Wen; Wang, Hong; Hupert, Mateusz; Witek, Makgorzata; Dharmasiri, Udara; Pingle, Maneesh R; Barany, Francis; Soper, Steven A

    2012-09-21

    The recent outbreaks of a lethal E. coli strain in Germany have aroused renewed interest in developing rapid, specific and accurate systems for detecting and characterizing bacterial pathogens in suspected contaminated food and/or water supplies. To address this need, we have designed, fabricated and tested an integrated modular-based microfluidic system and the accompanying assay for the strain-specific identification of bacterial pathogens. The system can carry out the entire molecular processing pipeline in a single disposable fluidic cartridge and detect single nucleotide variations in selected genes to allow for the identification of the bacterial species, even its strain with high specificity. The unique aspect of this fluidic cartridge is its modular format with task-specific modules interconnected to a fluidic motherboard to permit the selection of the target material. In addition, to minimize the amount of finishing steps for assembling the fluidic cartridge, many of the functional components were produced during the polymer molding step used to create the fluidic network. The operation of the cartridge was provided by electronic, mechanical, optical and hydraulic controls located off-chip and packaged into a small footprint instrument (1 ft(3)). The fluidic cartridge was capable of performing cell enrichment, cell lysis, solid-phase extraction (SPE) of genomic DNA, continuous flow (CF) PCR, CF ligase detection reaction (LDR) and universal DNA array readout. The cartridge was comprised of modules situated on a fluidic motherboard; the motherboard was made from polycarbonate, PC, and used for cell lysis, SPE, CF PCR and CF LDR. The modules were task-specific units and performed universal zip-code array readout or affinity enrichment of the target cells with both made from poly(methylmethacrylate), PMMA. Two genes, uidA and sipB/C, were used to discriminate between E. coli and Salmonella, and evaluated as a model system. Results showed that the fluidic

  1. Recent developments in antibody-based assays for the detection of bacterial toxins.

    Science.gov (United States)

    Zhu, Kui; Dietrich, Richard; Didier, Andrea; Doyscher, Dominik; Märtlbauer, Erwin

    2014-04-11

    Considering the urgent demand for rapid and accurate determination of bacterial toxins and the recent promising developments in nanotechnology and microfluidics, this review summarizes new achievements of the past five years. Firstly, bacterial toxins will be categorized according to their antibody binding properties into low and high molecular weight compounds. Secondly, the types of antibodies and new techniques for producing antibodies are discussed, including poly- and mono-clonal antibodies, single-chain variable fragments (scFv), as well as heavy-chain and recombinant antibodies. Thirdly, the use of different nanomaterials, such as gold nanoparticles (AuNPs), magnetic nanoparticles (MNPs), quantum dots (QDs) and carbon nanomaterials (graphene and carbon nanotube), for labeling antibodies and toxins or for readout techniques will be summarized. Fourthly, microscale analysis or minimized devices, for example microfluidics or lab-on-a-chip (LOC), which have attracted increasing attention in combination with immunoassays for the robust detection or point-of-care testing (POCT), will be reviewed. Finally, some new materials and analytical strategies, which might be promising for analyzing toxins in the near future, will be shortly introduced.

  2. Beetroot-pigment-derived colorimetric sensor for detection of calcium dipicolinate in bacterial spores.

    Directory of Open Access Journals (Sweden)

    Letícia Christina Pires Gonçalves

    Full Text Available In this proof-of-concept study, we describe the use of the main red beet pigment betanin for the quantification of calcium dipicolinate in bacterial spores, including Bacillus anthracis. In the presence of europium(III ions, betanin is converted to a water-soluble, non-luminescent orange 1∶1 complex with a stability constant of 1.4 × 10(5 L mol(-1. The addition of calcium dipicolinate, largely found in bacterial spores, changes the color of the aqueous solution of [Eu(Bn(+] from orange to magenta. The limit of detection (LOD of calcium dipicolinate is around 2.0 × 10(-6 mol L(-1 and the LOD determined for both spores, B. cereus and B. anthracis, is (1.1 ± 0.3× 10(6 spores mL(-1. This simple, green, fast and low cost colorimetric assay was selective for calcium dipicolinate when compared to several analogous compounds. The importance of this work relies on the potential use of betalains, raw natural pigments, as colorimetric sensors for biological applications.

  3. Beetroot-pigment-derived colorimetric sensor for detection of calcium dipicolinate in bacterial spores.

    Science.gov (United States)

    Gonçalves, Letícia Christina Pires; Da Silva, Sandra Maria; DeRose, Paul C; Ando, Rômulo Augusto; Bastos, Erick Leite

    2013-01-01

    In this proof-of-concept study, we describe the use of the main red beet pigment betanin for the quantification of calcium dipicolinate in bacterial spores, including Bacillus anthracis. In the presence of europium(III) ions, betanin is converted to a water-soluble, non-luminescent orange 1∶1 complex with a stability constant of 1.4 × 10(5) L mol(-1). The addition of calcium dipicolinate, largely found in bacterial spores, changes the color of the aqueous solution of [Eu(Bn)(+)] from orange to magenta. The limit of detection (LOD) of calcium dipicolinate is around 2.0 × 10(-6) mol L(-1) and the LOD determined for both spores, B. cereus and B. anthracis, is (1.1 ± 0.3)× 10(6) spores mL(-1). This simple, green, fast and low cost colorimetric assay was selective for calcium dipicolinate when compared to several analogous compounds. The importance of this work relies on the potential use of betalains, raw natural pigments, as colorimetric sensors for biological applications. PMID:24019934

  4. Hydrocarbon biodegradation and dynamic laser speckle for detecting chemotactic responses at low bacterial concentration

    Institute of Scientific and Technical Information of China (English)

    Melina Nisenbaum; Gonzalo Hernán Sendra; Gastón Alfredo Cerdá Gilbert; Marcelo Scagliola; Jorge Froilán González; Silvia Elena Murialdo

    2013-01-01

    We report on the biodegradation of pure hydrocarbons and chemotaxis towards these compounds by an isolated chlorophenol degrader,Pseudomonas strain H.The biochemical and phylogenetic analysis of the 16S rDNA sequence identified Pseudomonas strain H as having 99.56% similarity with P.aeruginosa PA01.This strain was able to degrade n-hexadecane,1-undecene,1-nonene,1-decene,1-dodecene and kerosene.It grew in the presence of 1-octene,while this hydrocarbons is toxic to other hydrocarbons degraders.Pseudomonas strain H was also chemotactic towards n-hexadecane,kerosene,1-undecene and 1-dodecene.These results show that this Pseudomonas strain H is an attractive candidate for hydrocarbon-containing wastewater bioremediation in controlled environments.Since the classical standard techniques for detecting chemotaxis are not efficient at low bacterial concentrations,we demonstrate the use of the dynamic speckle laser method,which is simple and inexpensive,to confirm bacterial chemotaxis at low cell concentrations (less than 105 colony-forming unit per millilitre (CFU/mL)) when hydrocarbons are the attractants.

  5. Detection of bacterial endospores by means of ultrafast coherent Raman spectroscopy

    Science.gov (United States)

    Pestov, Dmitry Sergeyevich

    This work is devoted to formulation and development of a laser spectroscopic technique for rapid detection of biohazards, such as Bacillus anthracis spores. Coherent anti-Stokes Raman scattering (CARS) is used as an underlying process for active retrieval of species-specific characteristics of an analyte. Vibrational modes of constituent molecules are Raman-excited by a pair of ultrashort, femtosecond laser pulses, and then probed through inelastic scattering of a third, time-delayed laser field. We first employ the already known time-resolved CARS technique. We apply it to the spectroscopy of easy-to-handle methanol-water mixtures, and then continue building our expertise on solutions of dipicolinic acid (DPA) and its salts, which happen to be marker molecules for bacterial spores. Various acquisition schemes are evaluated, and the preference is given to multi-channel frequency-resolved detection, when the whole CARS spectrum is recorded as a function of the probe pulse delay. We demonstrate a simple detection algorithm that manages to differentiate DPA solution from common interferents. We investigate experimentally the advantages and disadvantages of near-resonant probing of the excited molecular coherence, and finally observe the indicative backscattered CARS signal from DPA and NaDPA powders. The possibility of selective Raman excitation via pulse shaping of the preparation pulses is also demonstrated. The analysis of time-resolved CARS experiments on powders and B. subtilis spores, a harmless surrogate for B. anthracis, facilitates the formulation of a new approach, where we take full advantage of the multi-channel frequency-resolved acquisition and spectrally discriminate the Raman-resonant CARS signal from the background due to other instantaneous four-wave mixing (FWM) processes. Using narrowband probing, we decrease the magnitude of the nonresonant FWM, which is further suppressed by the timing of the laser pulses. The devised technique, referred to as

  6. A 16 × 16 CMOS Capacitive Biosensor Array Towards Detection of Single Bacterial Cell.

    Science.gov (United States)

    Couniot, Numa; Francis, Laurent A; Flandre, Denis

    2016-04-01

    We present a 16 × 16 CMOS biosensor array aiming at impedance detection of whole-cell bacteria. Each 14 μm × 16 μm pixel comprises high-sensitive passivated microelectrodes connected to an innovative readout interface based on charge sharing principle for capacitance-to-voltage conversion and subthreshold gain stage to boost the sensitivity. Fabricated in a 0.25 μm CMOS process, the capacitive array was experimentally shown to perform accurate dielectric measurements of the electrolyte up to electrical conductivities of 0.05 S/m, with maximal sensitivity of 55 mV/fF and signal-to-noise ratio (SNR) of 37 dB. As biosensing proof of concept, real-time detection of Staphylococcus epidermidis binding events was experimentally demonstrated and provides detection limit of ca. 7 bacteria per pixel and sensitivity of 2.18 mV per bacterial cell. Models and simulations show good matching with experimental results and provide a comprehensive analysis of the sensor and circuit system. Advantages, challenges and limits of the proposed capacitive biosensor array are finally described with regards to literature. With its small area and low power consumption, the present capacitive array is particularly suitable for portable point-of-care (PoC) diagnosis tools and lab-on-chip (LoC) systems. PMID:25974947

  7. Comparison of Two Suspension Arrays for Simultaneous Detection of Five Biothreat Bacterial in Powder Samples

    Directory of Open Access Journals (Sweden)

    Yu Yang

    2012-01-01

    Full Text Available We have developed novel Bio-Plex assays for simultaneous detection of Bacillus anthracis, Yersinia pestis, Brucella spp., Francisella tularensis, and Burkholderia pseudomallei. Universal primers were used to amplify highly conserved region located within the 16S rRNA amplicon, followed by hybridized to pathogen-specific probes for identification of these five organisms. The other assay is based on multiplex PCR to simultaneously amplify five species-specific pathogen identification-targeted regions unique to individual pathogen. Both of the two arrays are validated to be flexible and sensitive for simultaneous detection of bioterrorism bacteria. However, universal primer PCR-based array could not identify Bacillus anthracis, Yersinia pestis, and Brucella spp. at the species level because of the high conservation of 16S rDNA of the same genus. The two suspension arrays can be utilized to detect Bacillus anthracis sterne spore and Yersinia pestis EV76 from mimic “write powder” samples, they also proved that the suspension array system will be valuable tools for diagnosis of bacterial biothreat agents in environmental samples.

  8. Preparation of Pd/Bacterial Cellulose Hybrid Nanofibers for Dopamine Detection

    Directory of Open Access Journals (Sweden)

    Dawei Li

    2016-05-01

    Full Text Available Palladium nanoparticle-bacterial cellulose (PdBC hybrid nanofibers were synthesized by in-situ chemical reduction method. The obtained PdBC nanofibers were characterized by a series of analytical techniques. The results revealed that Pd nanoparticles were evenly dispersed on the surfaces of BC nanofibers. Then, the as-prepared PdBC nanofibers were mixed with laccase (Lac and Nafion to obtain mixture suspension, which was further modified on electrode surface to construct novel biosensing platform. Finally, the prepared electrochemical biosensor was employed to detect dopamine. The analysis result was satisfactory, the sensor showed excellent electrocatalysis towards dopamine with high sensitivity (38.4 µA·mM−1, low detection limit (1.26 µM, and wide linear range (5–167 µM. Moreover, the biosensor also showed good repeatability, reproducibility, selectivity and stability and was successfully used in the detection of dopamine in human urine, thus providing a promising method for dopamine analysis in clinical application.

  9. Preparation of Pd/Bacterial Cellulose Hybrid Nanofibers for Dopamine Detection.

    Science.gov (United States)

    Li, Dawei; Ao, Kelong; Wang, Qingqing; Lv, Pengfei; Wei, Qufu

    2016-01-01

    Palladium nanoparticle-bacterial cellulose (PdBC) hybrid nanofibers were synthesized by in-situ chemical reduction method. The obtained PdBC nanofibers were characterized by a series of analytical techniques. The results revealed that Pd nanoparticles were evenly dispersed on the surfaces of BC nanofibers. Then, the as-prepared PdBC nanofibers were mixed with laccase (Lac) and Nafion to obtain mixture suspension, which was further modified on electrode surface to construct novel biosensing platform. Finally, the prepared electrochemical biosensor was employed to detect dopamine. The analysis result was satisfactory, the sensor showed excellent electrocatalysis towards dopamine with high sensitivity (38.4 µA·mM(-1)), low detection limit (1.26 µM), and wide linear range (5-167 µM). Moreover, the biosensor also showed good repeatability, reproducibility, selectivity and stability and was successfully used in the detection of dopamine in human urine, thus providing a promising method for dopamine analysis in clinical application. PMID:27187327

  10. Detection of NASBA amplified bacterial tmRNA molecules on SLICSel designed microarray probes

    Directory of Open Access Journals (Sweden)

    Toome Kadri

    2011-02-01

    Full Text Available Abstract Background We present a comprehensive technological solution for bacterial diagnostics using tmRNA as a marker molecule. A robust probe design algorithm for microbial detection microarray is implemented. The probes were evaluated for specificity and, combined with NASBA (Nucleic Acid Sequence Based Amplification amplification, for sensitivity. Results We developed a new web-based program SLICSel for the design of hybridization probes, based on nearest-neighbor thermodynamic modeling. A SLICSel minimum binding energy difference criterion of 4 kcal/mol was sufficient to design of Streptococcus pneumoniae tmRNA specific microarray probes. With lower binding energy difference criteria, additional hybridization specificity tests on the microarray were needed to eliminate non-specific probes. Using SLICSel designed microarray probes and NASBA we were able to detect S. pneumoniae tmRNA from a series of total RNA dilutions equivalent to the RNA content of 0.1-10 CFU. Conclusions The described technological solution and both its separate components SLICSel and NASBA-microarray technology independently are applicative for many different areas of microbial diagnostics.

  11. Detection of NASBA amplified bacterial tmRNA molecules on SLICSel designed microarray probes

    LENUS (Irish Health Repository)

    Scheler, Ott

    2011-02-28

    Abstract Background We present a comprehensive technological solution for bacterial diagnostics using tmRNA as a marker molecule. A robust probe design algorithm for microbial detection microarray is implemented. The probes were evaluated for specificity and, combined with NASBA (Nucleic Acid Sequence Based Amplification) amplification, for sensitivity. Results We developed a new web-based program SLICSel for the design of hybridization probes, based on nearest-neighbor thermodynamic modeling. A SLICSel minimum binding energy difference criterion of 4 kcal\\/mol was sufficient to design of Streptococcus pneumoniae tmRNA specific microarray probes. With lower binding energy difference criteria, additional hybridization specificity tests on the microarray were needed to eliminate non-specific probes. Using SLICSel designed microarray probes and NASBA we were able to detect S. pneumoniae tmRNA from a series of total RNA dilutions equivalent to the RNA content of 0.1-10 CFU. Conclusions The described technological solution and both its separate components SLICSel and NASBA-microarray technology independently are applicative for many different areas of microbial diagnostics.

  12. Detection and identification of putative bacterial endosymbionts and endogenous viruses in tick cell lines☆

    Science.gov (United States)

    Alberdi, M. Pilar; Dalby, Matthew J.; Rodriguez-Andres, Julio; Fazakerley, John K.; Kohl, Alain; Bell-Sakyi, Lesley

    2012-01-01

    As well as being vectors of many viral, bacterial, and protozoan pathogens of medical and veterinary importance, ticks harbour a variety of microorganisms which are not known to be pathogenic for vertebrate hosts. Continuous cell lines established from ixodid and argasid ticks could be infected with such endosymbiotic bacteria and endogenous viruses, but to date very few cell lines have been examined for their presence. DNA and RNA extracted from over 50 tick cell lines deposited in the Roslin Wellcome Trust Tick Cell Biobank (http://tickcells.roslin.ac.uk) were screened for presence of bacteria and RNA viruses, respectively. Sequencing of PCR products amplified using pan-16S rRNA primers revealed the presence of DNA sequences from bacterial endosymbionts in several cell lines derived from Amblyomma and Dermacentor spp. ticks. Identification to species level was attempted using Rickettsia- and Francisella-specific primers. Pan-Nairovirus primers amplified PCR products of uncertain specificity in cell lines derived from Rhipicephalus, Hyalomma, Ixodes, Carios, and Ornithodoros spp. ticks. Further characterisation attempted with primers specific for Crimean-Congo haemorrhagic fever virus segments confirmed the absence of this arbovirus in the cells. A set of pan-Flavivirus primers did not detect endogenous viruses in any of the cell lines. Transmission electron microscopy revealed the presence of endogenous reovirus-like viruses in many of the cell lines; only 4 of these lines gave positive results with primers specific for the tick Orbivirus St Croix River virus, indicating that there may be additional, as yet undescribed ‘tick-only’ viruses inhabiting tick cell lines. PMID:22743047

  13. Detection and identification of putative bacterial endosymbionts and endogenous viruses in tick cell lines.

    Science.gov (United States)

    Alberdi, M Pilar; Dalby, Matthew J; Rodriguez-Andres, Julio; Fazakerley, John K; Kohl, Alain; Bell-Sakyi, Lesley

    2012-06-01

    As well as being vectors of many viral, bacterial, and protozoan pathogens of medical and veterinary importance, ticks harbour a variety of microorganisms which are not known to be pathogenic for vertebrate hosts. Continuous cell lines established from ixodid and argasid ticks could be infected with such endosymbiotic bacteria and endogenous viruses, but to date very few cell lines have been examined for their presence. DNA and RNA extracted from over 50 tick cell lines deposited in the Roslin Wellcome Trust Tick Cell Biobank (http://tickcells.roslin.ac.uk) were screened for presence of bacteria and RNA viruses, respectively. Sequencing of PCR products amplified using pan-16S rRNA primers revealed the presence of DNA sequences from bacterial endosymbionts in several cell lines derived from Amblyomma and Dermacentor spp. ticks. Identification to species level was attempted using Rickettsia- and Francisella-specific primers. Pan-Nairovirus primers amplified PCR products of uncertain specificity in cell lines derived from Rhipicephalus, Hyalomma, Ixodes, Carios, and Ornithodoros spp. ticks. Further characterisation attempted with primers specific for Crimean-Congo haemorrhagic fever virus segments confirmed the absence of this arbovirus in the cells. A set of pan-Flavivirus primers did not detect endogenous viruses in any of the cell lines. Transmission electron microscopy revealed the presence of endogenous reovirus-like viruses in many of the cell lines; only 4 of these lines gave positive results with primers specific for the tick Orbivirus St Croix River virus, indicating that there may be additional, as yet undescribed 'tick-only' viruses inhabiting tick cell lines.

  14. Detection of Pneumocystis DNA in samples from patients suspected of bacterial pneumonia – a case-control study

    DEFF Research Database (Denmark)

    Helweg-Larsen, J; Jensen, JS; Dohn, G;

    2002-01-01

    Pneumocystis jiroveci (formerly known as P. carinii f.sp. hominis) is an opportunistic fungus that causes Pneumocystis pneumonia (PCP) in immunocompromised individuals. Pneumocystis jiroveci can be detected by polymerase chain reaction (PCR). To investigate the clinical importance of a positive...... Pneumocystis-PCR among HIV-uninfected patients suspected of bacterial pneumonia, a retrospective matched case-control study was conducted....

  15. Construction and comparison of fluorescence and bioluminescence bacterial biosensors for the detection of bioavailable toluene and related compounds

    International Nuclear Information System (INIS)

    Environmental pollution with petroleum products such as benzene, toluene, ethylbenzene, and xylenes (BTEX) has garnered increasing awareness because of its serious consequences for human health and the environment. We have constructed toluene bacterial biosensors comprised of two reporter genes, gfp and luxCDABE, characterized by green fluorescence and luminescence, respectively, and compared their abilities to detect bioavailable toluene and related compounds. The bacterial luminescence biosensor allowed faster and more-sensitive detection of toluene; the fluorescence biosensor strain was much more stable and thus more applicable for long-term exposure. Both luminescence and fluorescence biosensors were field-tested to measure the relative bioavailability of BTEX in contaminated groundwater and soil samples. The estimated BTEX concentrations determined by the luminescence and fluorescence bacterial biosensors were closely comparable to each other. Our results demonstrate that both bacterial luminescence and fluorescence biosensors are useful in determining the presence and the bioavailable fractions of BTEX in the environment. - The choice of reporter genes for toluene bacterial biosensors to determine BTEX bioavailability is case-specific

  16. Chemical polyglycosylation and nanolitre detection enables single-molecule recapitulation of bacterial sugar export

    Science.gov (United States)

    Kong, Lingbing; Almond, Andrew; Bayley, Hagan; Davis, Benjamin G.

    2016-05-01

    The outermost protective layer of both Gram-positive and Gram-negative bacteria is composed of bacterial capsular polysaccharides. Insights into the interactions between the capsular polysaccharide and its transporter and the mechanism of sugar export would not only increase our understanding of this key process, but would also help in the design of novel therapeutics to block capsular polysaccharide export. Here, we report a nanolitre detection system that makes use of the bilayer interface between two droplets, and we use this system to study single-molecule recapitulation of sugar export. A synthetic strategy of polyglycosylation based on tetrasaccharide monomers enables ready synthetic access to extended fragments of K30 oligosaccharides and polysaccharides. Examination of the interactions between the Escherichia coli sugar transporter Wza and very small amounts of fragments of the K30 capsular polysaccharide substrate reveal the translocation of smaller but not larger fragments. We also observe capture events that occur only on the intracellular side of Wza, which would complement coordinated feeding by adjunct biosynthetic machinery.

  17. Development of Simple Bacterial Biosensor for Phenol Detection in Water at Medium Concentration using Glass Microelectrode

    Directory of Open Access Journals (Sweden)

    Setyawan Purnomo Sakti

    2016-01-01

    Full Text Available Water is one of the most fundamental natural resources in earth. The availability of clean water becomes a global interest. Many human activities result in water pollution. One from many pollution substances in water is phenol. Phenol is a very common residual compound in industrial activity. Extensive use of phenol in industry degrades water quality. Regulation has been set in many countries to prevent further damage to the water resource caused by phenol and limiting phenol concentration in water before released into the environment. Therefor it is importance to develop a sensor which can detect phenol concentration in water to be used as a wastewater quality control system. This paper presents a development of bacterial biosensor using Pseudomonas putida and Pseudomonas fluorescens as a biological sensitive material. The sensor was made from glass micro electrode using Ag/AgCl electrode as reference electrode, silver electrode and cellulose ester. The Pseudomonas putida was entrapped inside the nutrient solution and separated by cellulose ester membrane from water containing phenol. It was found that the Pseudomonas putida in used must be growth in 10 hours to reach its optimum growth condition. Linear relationship between biosensor output voltages to phenol concentration was measured for phenol concentration below 200 ppm. The sensitivity of the developed biosensor was 72mV/ppm for Pseudomonas putida and 68.8 mV/ppm for Pseudomonas fluorescens.

  18. Mass Spectrometric Detection of Bacterial Protein Toxins and Their Enzymatic Activity.

    Science.gov (United States)

    Kalb, Suzanne R; Boyer, Anne E; Barr, John R

    2015-08-31

    Mass spectrometry has recently become a powerful technique for bacterial identification. Mass spectrometry approaches generally rely upon introduction of the bacteria into a matrix-assisted laser-desorption time-of-flight (MALDI-TOF) mass spectrometer with mass spectrometric recognition of proteins specific to that organism that form a reliable fingerprint. With some bacteria, such as Bacillus anthracis and Clostridium botulinum, the health threat posed by these organisms is not the organism itself, but rather the protein toxins produced by the organisms. One such example is botulinum neurotoxin (BoNT), a potent neurotoxin produced by C. botulinum. There are seven known serotypes of BoNT, A-G, and many of the serotypes can be further differentiated into toxin variants, which are up to 99.9% identical in some cases. Mass spectrometric proteomic techniques have been established to differentiate the serotype or toxin variant of BoNT produced by varied strains of C. botulinum. Detection of potent biological toxins requires high analytical sensitivity and mass spectrometry based methods have been developed to determine the enzymatic activity of BoNT and the anthrax lethal toxins produced by B. anthracis. This enzymatic activity, unique for each toxin, is assessed with detection of the toxin-induced cleavage of strategically designed peptide substrates by MALDI-TOF mass spectrometry offering unparalleled specificity. Furthermore, activity assays allow for the assessment of the biological activity of a toxin and its potential health risk. Such methods have become important diagnostics for botulism and anthrax. Here, we review mass spectrometry based methods for the enzymatic activity of BoNT and the anthrax lethal factor toxin.

  19. Nanolitre real-time PCR detection of bacterial, parasitic, and viral agents from patients with diarrhoea in Nunavut, Canada

    Directory of Open Access Journals (Sweden)

    David M. Goldfarb

    2013-04-01

    Full Text Available Background. Little is known about the microbiology of diarrhoeal disease in Canada's Arctic regions. There are a number of limitations of conventional microbiology testing techniques for diarrhoeal pathogens, and these may be further compromised in the Arctic, given the often long distances for specimen transport. Objective. To develop a novel multiple-target nanolitre real-time reverse transcriptase (RT-PCR platform to simultaneously test diarrhoeal specimens collected from residents of the Qikiqtani (Baffin Island Region of Nunavut, Canada, for a wide range of bacterial, parasitic and viral agents. Study design/methods. Diarrhoeal stool samples submitted for bacterial culture to Qikiqtani General Hospital in Nunavut over an 18-month period were tested with a multiple-target nanolitre real-time PCR panel for major diarrhoeal pathogens including 8 bacterial, 6 viral and 2 parasitic targets. Results. Among 86 stool specimens tested by PCR, a total of 50 pathogens were detected with 1 or more pathogens found in 40 (46.5% stool specimens. The organisms detected comprised 17 Cryptosporidium spp., 5 Clostridium difficile with toxin B, 6 Campylobacter spp., 6 Salmonella spp., 4 astroviruses, 3 noroviruses, 1 rotavirus, 1 Shigella spp. and 1 Giardia spp. The frequency of detection by PCR and bacterial culture was similar for Salmonella spp., but discrepant for Campylobacter spp., as Campylobacter was detected by culture from only 1/86 specimens. Similarly, Cryptosporidium spp. was detected in multiple samples by PCR but was not detected by microscopy or enzyme immunoassay. Conclusions. Cryptosporidium spp., Campylobacter spp. and Clostridium difficile may be relatively common but possibly under-recognised pathogens in this region. Further study is needed to determine the regional epidemiology and clinical significance of these organisms. This method appears to be a useful tool for gastrointestinal pathogen research and may also be helpful for clinical

  20. Direct detection of fatty acid ethyl esters using low temperature plasma (LTP) ambient ionization mass spectrometry for rapid bacterial differentiation.

    Science.gov (United States)

    Zhang, J Isabella; Costa, Anthony B; Tao, W Andy; Cooks, R Graham

    2011-08-01

    Low temperature plasma mass spectrometry (LTP-MS) was employed to detect fatty acid ethyl esters (FAEE) from bacterial samples directly. Positive ion mode FAEE mass spectrometric profiles of sixteen different bacterial samples were obtained without extraction or other sample preparation. In the range m/z 200-300, LTP mass spectra show highly reproducible and characteristic patterns. To identify the FAEE's associated with the characteristic peaks, accurate masses were recorded in the full scan mode using an LTQ/Orbitrap instrument, and tandem mass spectrometry was performed. Data were examined by principal component analysis (PCA) to determine the degree of differentiation possible amongst different bacterial species. Gram-positive and gram-negative bacteria are readily distinguished, and 11 out of 13 Salmonella strains show distinctive patterns. Growth media effects are observed but do not interfere with species recognition based on the PCA results. PMID:21706093

  1. Evaluation of bacterial contamination rate of the anterior chamber during phacoemulsification surgery using an automated microbial detection system

    Institute of Scientific and Technical Information of China (English)

    Ibrahim; Kocak; Funda; Kocak; Bahri; Teker; Ali; Aydin; Faruk; Kaya; Hakan; Baybora

    2014-01-01

    ·AIM: To assess the incidence of anterior chamber bacterial contamination during phacoemulsification surgery using an automated microbial detection system(BacT/Alert).·METHODS: Sixty-nine eyes of 60 patients who had uneventful phacoemulsification surgery, enrolled in this prospective study. No prophylactic topical or systemic antibiotics were used before surgery. After antisepsis with povidone-iodine, two intraoperative anterior chamber aqueous samples were obtained, the first whilst entering anterior chamber, and the second at the end of surgery. BacT/Alert culture system was used to detect bacterial contamination in the aqueous samples.·RESULTS: Neither aqueous samples obtained at the beginning nor conclusion of the surgery was positive for microorganisms on BacT/Alert culture system. The rate of bacterial contamination during surgery was 0%. None of the eyes developed acute-onset endophthalmitis after surgery.· CONCLUSION: In this study, no bacterial contamination of anterior chamber was observed during cataract surgery. This result shows that meticulous surgical preparation and technique can prevent anterior chamber contamination during phacoemulsification cataract surgery.

  2. One-day workflow scheme for bacterial pathogen detection and antimicrobial resistance testing from blood cultures.

    Science.gov (United States)

    Hansen, Wendy L J; Beuving, Judith; Verbon, Annelies; Wolffs, Petra F G

    2012-07-09

    Bloodstream infections are associated with high mortality rates because of the probable manifestation of sepsis, severe sepsis and septic shock(1). Therefore, rapid administration of adequate antibiotic therapy is of foremost importance in the treatment of bloodstream infections. The critical element in this process is timing, heavily dependent on the results of bacterial identification and antibiotic susceptibility testing. Both of these parameters are routinely obtained by culture-based testing, which is time-consuming and takes on average 24-48 hours(2, 4). The aim of the study was to develop DNA-based assays for rapid identification of bloodstream infections, as well as rapid antimicrobial susceptibility testing. The first assay is a eubacterial 16S rDNA-based real-time PCR assay complemented with species- or genus-specific probes(5). Using these probes, Gram-negative bacteria including Pseudomonas spp., Pseudomonas aeruginosa and Escherichia coli as well as Gram-positive bacteria including Staphylococcus spp., Staphylococcus aureus, Enterococcus spp., Streptococcus spp., and Streptococcus pneumoniae could be distinguished. Using this multiprobe assay, a first identification of the causative micro-organism was given after 2 h. Secondly, we developed a semi-molecular assay for antibiotic susceptibility testing of S. aureus, Enterococcus spp. and (facultative) aerobe Gram-negative rods(6). This assay was based on a study in which PCR was used to measure the growth of bacteria(7). Bacteria harvested directly from blood cultures are incubated for 6 h with a selection of antibiotics, and following a Sybr Green-based real-time PCR assay determines inhibition of growth. The combination of these two methods could direct the choice of a suitable antibiotic therapy on the same day (Figure 1). In conclusion, molecular analysis of both identification and antibiotic susceptibility offers a faster alternative for pathogen detection and could improve the diagnosis of

  3. Detection of ST Segment Elevation Myocardial Infarction (STEMI Using Bacterial Foraging Optimization Technique

    Directory of Open Access Journals (Sweden)

    Bensujin

    2014-05-01

    Full Text Available The rife of heart disease (HD is a comprehensive phenomenon, and the scale of the cardiovascular disease (CVD increases in prevalence in the developed world. Cardio vascular disease (CVD is the foremost cause of death worldwide; the World Health Organization (WHO estimates that globally 17.3 million people died from Heart Disease in 2008, representing 30% of global deaths. The forecast of heart disease is a multi-layered problem, which is not free from false assumptions. The eminence of the clinical decisions and the effect of the stratagems should optimize the patient’s outcomes and to lessen the risk of disease factors, if the methods are applied effectively and properly grounded on the expert analysis on the presented data. The major clinical information related to heart disease can be obtained by the analysis for electrocardiograph (ECG signal. The ST segment Myocardial Infarction (STEMI is the severe type and the elevated ST segment on the ECG data represents that large amount of heart muscle mutilation is stirring. In this paper we recommend a constructive approach to identify the STEMI in the ECG signal of a person. The sample ECG data’s are acquired from the MIT-BIH databases. Those data’s are subsequently pre-processed; the ST segment is extracted and then measured to identify the availability of the disease. During the ST segment analysis stage the beats generated by the ventricular in origin or ventricular paced are resolute. The fine-tuned data set is converted into a formatted data set and conceded to the Bacterial Foraging Optimization Algorithm (BFOA to detect the approximate solution. The proposed system overcomes the superseded algorithms by a focussed update in the methodology with reliable algorithms and techniques.

  4. Nucleic Acid-Based Detection and Identification of Bacterial and Fungal Plant Pathogens - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Kingsley, Mark T.

    2001-03-13

    The threat to American interests from terrorists is not limited to attacks against humans. Terrorists might seek to inflict damage to the U.S. economy by attacking our agricultural sector. Infection of commodity crops by bacterial or fungal crop pathogens could adversely impact U.S. agriculture, either directly from damage to crops or indirectly from damage to our ability to export crops suspected of contamination. Recognizing a terrorist attack against U.S. agriculture, to be able to prosecute the terrorists, is among the responsibilities of the members of Hazardous Material Response Unit (HMRU) of the Federal Bureau of Investigation (FBI). Nucleic acid analysis of plant pathogen strains by the use of polymerase chain reaction (PCR) amplification techniques is a powerful method for determining the exact identity of pathogens, as well as their possible region of origin. This type of analysis, however, requires that PCR assays be developed specific to each particular pathogen strain, and analysis protocols developed that are specific to the particular instrument used for detection. The objectives of the work described here were threefold: 1) to assess the potential terrorist threat to U.S. agricultural crops, 2) to determine whether suitable assays exist to monitor that threat, and 3) where assays are needed for priority plant pathogen threats, to modify or develop those assays for use by specialists at the HMRU. The assessment of potential threat to U.S. commodity crops and the availability of assays for those threats were described in detail in the Technical Requirements Document (9) and will be summarized in this report. This report addresses development of specific assays identified in the Technical Requirements Document, and offers recommendations for future development to ensure that HMRU specialists will be prepared with the PCR assays they need to protect against the threat of economic terrorism.

  5. Computational modeling and experimental characterization of bacterial microcolonies for rapid detection using light scattering

    Science.gov (United States)

    Bai, Nan

    A label-free and nondestructive optical elastic forward light scattering method has been extended for the analysis of microcolonies for food-borne bacteria detection and identification. To understand the forward light scattering phenomenon, a model based on the scalar diffraction theory has been employed: a bacterial colony is considered as a biological spatial light modulator with amplitude and phase modulation to the incoming light, which continues to propagate to the far-field to form a distinct scattering 'fingerprint'. Numerical implementation via angular spectrum method (ASM) and Fresnel approximation have been carried out through Fast Fourier Transform (FFT) to simulate this optical model. Sampling criteria to achieve unbiased and un-aliased simulation results have been derived and the effects of violating these conditions have been studied. Diffraction patterns predicted by these two methods (ASM and Fresnel) have been compared to show their applicability to different simulation settings. Through the simulation work, the correlation between the colony morphology and its forward scattering pattern has been established to link the number of diffraction rings and the half cone angle with the diameter and the central height of the Gaussian-shaped colonies. In order to experimentally prove the correlation, a colony morphology analyzer has been built and used to characterize the morphology of different bacteria genera and investigate their growth dynamics. The experimental measurements have demonstrated the possibility of differentiating bacteria Salmonella, Listeria, Escherichia in their early growth stage (100˜500 µm) based on their phenotypic characteristics. This conclusion has important implications in microcolony detection, as most bacteria of our interest need much less incubation time (8˜12 hours) to grow into this size range. The original forward light scatterometer has been updated to capture scattering patterns from microcolonies. Experiments have

  6. Perception of BDS students and fresh graduates about significance of professional ethics in dentistry

    International Nuclear Information System (INIS)

    Objective: To assess the awareness level of undergraduate dentistry students as well as fresh graduates about the significance of professional ethics. Methods: The cross sectional study was conducted among the 3rd, 4th and final year male and female BDS students as well as fresh graduate Interns from the College of Dentistry, King Saud University from January to June 2011. The students were asked to give their opinion about need for applications of professional ethics in dental practice on a five point Likert Scale varying from strongly agree to strongly disagree. Minitab statistical software was used for data analysis. Results: Students at all levels considered professional ethics a very important prerequisite for dental practice with overall mean value of 4.42+-0.36. However, the responses from the senior academic levels were significantly on the higher side compared to those from the junior grades. Generally the religious teachings and spirituality was considered as one of the top most motives for practicing professional ethics in dentistry followed by reputation, financial benefits, fear of punishment and self projection, with overall mean values of 3.93+-0.58, 3.81+-0.49, 3.25+-0.94, 3.21+-1.07 and 3.16+-1.04, respectively. Conclusion: The present findings revealed that Professional Ethics is appreciated by the students as a highly significant factor for their success in dental practice as well as acquiring a good name and position in the society. (author)

  7. Detecting the dormant: a review of recent advances in molecular techniques for assessing the viability of bacterial endospores.

    Science.gov (United States)

    Mohapatra, Bidyut R; La Duc, Myron T

    2013-09-01

    Due to their contribution to gastrointestinal and pulmonary disease, their ability to produce various deadly exotoxins, and their resistance to extreme temperature, pressure, radiation, and common chemical disinfecting agents, bacterial endospores of the Firmicutes phylum are a major concern for public and environmental health. In addition, the hardy and dormant nature of endospores renders them a particularly significant threat to the integrity of robotic extraterrestrial life-detection investigations. To prevent the contamination of critical surfaces with seemingly ubiquitous bacterial endospores, clean rooms maintained at exceedingly stringent cleanliness levels (i.e., fewer than 100,000 airborne particles per ft(3)) are used for surgical procedures, pharmaceutical processing and packaging, and fabrication and assembly of medical devices and spacecraft components. However, numerous spore-forming bacterial species have been reported to withstand typical clean room bioreduction strategies (e.g., UV lights, maintained humidity, paucity of available nutrients), which highlights the need for rapid and reliable molecular methods for detecting, enumerating, and monitoring the incidence of viable endospores. Robust means of evaluating and tracking spore burden not only provide much needed information pertaining to endospore ecophysiology in different environmental niches but also empower decontamination and bioreduction strategies aimed at sustaining the reliability and integrity of clean room environments. An overview of recent molecular advances in detecting and enumerating viable endospores, as well as the expanding phylogenetic diversity of pathogenic and clean room-associated spore-forming bacteria, ensues.

  8. Detecting the dormant: a review of recent advances in molecular techniques for assessing the viability of bacterial endospores.

    Science.gov (United States)

    Mohapatra, Bidyut R; La Duc, Myron T

    2013-09-01

    Due to their contribution to gastrointestinal and pulmonary disease, their ability to produce various deadly exotoxins, and their resistance to extreme temperature, pressure, radiation, and common chemical disinfecting agents, bacterial endospores of the Firmicutes phylum are a major concern for public and environmental health. In addition, the hardy and dormant nature of endospores renders them a particularly significant threat to the integrity of robotic extraterrestrial life-detection investigations. To prevent the contamination of critical surfaces with seemingly ubiquitous bacterial endospores, clean rooms maintained at exceedingly stringent cleanliness levels (i.e., fewer than 100,000 airborne particles per ft(3)) are used for surgical procedures, pharmaceutical processing and packaging, and fabrication and assembly of medical devices and spacecraft components. However, numerous spore-forming bacterial species have been reported to withstand typical clean room bioreduction strategies (e.g., UV lights, maintained humidity, paucity of available nutrients), which highlights the need for rapid and reliable molecular methods for detecting, enumerating, and monitoring the incidence of viable endospores. Robust means of evaluating and tracking spore burden not only provide much needed information pertaining to endospore ecophysiology in different environmental niches but also empower decontamination and bioreduction strategies aimed at sustaining the reliability and integrity of clean room environments. An overview of recent molecular advances in detecting and enumerating viable endospores, as well as the expanding phylogenetic diversity of pathogenic and clean room-associated spore-forming bacteria, ensues. PMID:23912118

  9. Reduced accuracy of 14C-D-xylose breath test for detecting bacterial overgrowth in gastrointestinal motility disorders

    International Nuclear Information System (INIS)

    The accuracy of the 14C-D-xylose breath test in the diagnosis of small-bowel bacterial overgrowth was prospectively evaluated in 10 patients with motility disorders: 6 myopathic, 3 neuropathic, and 1 mechanical obstruction. 6 of 10 patients had small-bowel bacterial overgrowth on culture of small-bowel aspirate. Increased breath 14CO2 levels were documented in 3 of 6 patients with positive cultures and in 2 of 4 with negative cultures. 2 patients with positive results by both methods and 1 of 2 with positive breath 14CO2 but negative cultures had previously undergone gastric surgery. 3 patients with myopathic dysmotility had positive cultures but negative breath tests. Cultures of duodenal aspirates and the D-xylose test had sensitivities of 80% and 40%, respectively, for the finding of hypoalbuminemia. Compared with cultures, the sensitivity and specificity of the breath test were 60% and 40%, respectively. Impaired delivery of 14C-D-xylose for bacterial metabolism may result from postprandial antral hypomotility or low amplitude small-bowel motility, contributing to the false-negative breath tests. Thus, cultures is the optimal method to detect small-bowel bacterial overgrowth in patients with motility disorders. 25 refs., 1 fig., 4 tabs

  10. LHCb: Measurement of the relative yields of the decay modes $B_{d,s} \\to D^{\\pm}_{(s)}\\pi^{\\mp}$ and $B_{d,s} \\to D^{\\pm}_{(s)} K^{\\pm}$ and determination of $f_d /f_s$ for 7 TeV $pp$ collisions

    CERN Multimedia

    David, P; Morawski, P; Witek, M; Akiba, K; Serra, N; Storaci, B; Tuning, N; Williams, M; Easo, S; Carson, L; Poluektov, A

    2011-01-01

    A fit to the invariant mass distributions is used to determine the relative abundances of the four decay modes $B_{d,s} \\to D^{\\pm}_{(s)}\\pi^{\\mp}$ and $B_{d,s} \\to D^{\\pm}_{(s)} K^{\\mp}$ for $B_{d,s}$ mesons produced in 7 TeV $pp$ collisions at the LHC. From these, the relative branching fractions of the kaon modes with respect to the pion modes, and the value of $f_d /f_s$, are determined.

  11. Polymerase Chain Reaction (PCR) Versus Bacterial Culture in Detection of Organisms in Otitis Media with Effusion (OME) in Children.

    Science.gov (United States)

    Aly, Balegh H; Hamad, Mostafa S; Mohey, Mervat; Amen, Sameh

    2012-03-01

    The aim of this study was to compare between polymerase chain reaction (PCR) and bacterial culture in detection of Streptococcus Pneumonia and M. Catarrhalis in otitis media with effusion (OME) in children. Fifty patients having OME were included in this study between 2003 and 2008. Myringotomy and tympanostomy tube insertion were done in every patient and the middle ear effusion samples were aspirated. The samples were subjected to bacteriological study in the form of culture and molecular study in the form of PCR using JM201/202-204 primer probe set for both S. pneumonia and M. catarrhalis. The results of Bacterial cultures are as follows: five cases (10%) were culture positive for S. pneumonia. Six cases (12%) were culture positive for M. catarrhalis. Only one case (2%) showed positively for both S. pneumonia and M. catarrhalis. Polymerase chain reaction test shows that 18 cases (36%) were positive for S. pneumonia, 22 cases (44%) were positive for M. catarrhalis, 6 cases (12%) were positive for both organism and 4 cases (8%) were negative. The difference between the proportion of culture positive and PCR positive specimens for both organisms individually and collectively was significant (P PCR is more accurate than bacterial culture in detection of organisms in middle ear fluid in OME and that M. catarrhalis plays a significant rule in OME as it is the sole organism identified more than the other one by PCR.

  12. Development and application of monoclonal antibodies for in situ detection of indigenous bacterial strains in aquatic ecosystems.

    Science.gov (United States)

    Faude, U C; Höfle, M G

    1997-11-01

    Strain-specific monoclonal antibodies (MAbs) were developed for three different bacterial isolates obtained from a freshwater environment (Lake Plusssee) in the spring of 1990. The three isolates, which were identified by molecular methods, were as follows: Cytophaga johnsonae PX62, Comamonas acidovorans PX54, and Aeromonas hydrophila PU7718. These strains represented three species that were detected in high abundance during a set of mesocosm experiments in Lake Plusssee by the direct analysis of low-molecular-weight RNAs from bacterioplankton. We developed one MAb each for the bacterial isolates PX54 and PU7718 that did not show any cross-reactivity with other bacterial strains by immunofluorescence microscopy. Each MAb recognized the general lipopolysaccharide fraction of the homologous strain. These MAbs were tested successfully for their ability to be used for the in situ detection and counting of bacteria in lake water by immunofluorescence microscopy. During the spring of 1993, A. hydrophila PU7718 showed a depth distribution in Lake Plusssee with a pronounced maximum abundance at 6 m, whereas Comamonas acidovorans PX54 showed a depth distribution with a maximum abundance at the surface. The application of these MAbs to the freshwater samples enabled us to determine the cell morphologies and microhabitats of these strains within their natural environment. The presence of as many as 8,000 cells of these strains per ml in their original habitats 3 years after their initial isolation demonstrated the persistence of individual strains of heterotrophic bacteria over long time spans in pelagic habitats. PMID:9361440

  13. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff.

    Science.gov (United States)

    Miller, Melissa A; Byrne, Barbara A; Jang, Spencer S; Dodd, Erin M; Dorfmeier, Elene; Harris, Michael D; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A; Miller, Woutrina A

    2010-01-01

    Although protected for nearly a century, California's sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health. PMID:19720009

  14. Beetroot-Pigment-Derived Colorimetric Sensor for Detection of Calcium Dipicolinate in Bacterial Spores

    OpenAIRE

    Letícia Christina Pires Gonçalves; Sandra Maria Da Silva; DeRose, Paul C.; Rômulo Augusto Ando; Erick Leite Bastos

    2013-01-01

    In this proof-of-concept study, we describe the use of the main red beet pigment betanin for the quantification of calcium dipicolinate in bacterial spores, including Bacillus anthracis. In the presence of europium(III) ions, betanin is converted to a water-soluble, non-luminescent orange 1∶1 complex with a stability constant of 1.4 × 10(5) L mol(-1). The addition of calcium dipicolinate, largely found in bacterial spores, changes the color of the aqueous solution of [Eu(Bn)(+)] from orange t...

  15. A bioinformatic strategy for the detection, classification and analysis of bacterial autotransporters.

    Directory of Open Access Journals (Sweden)

    Nermin Celik

    Full Text Available Autotransporters are secreted proteins that are assembled into the outer membrane of bacterial cells. The passenger domains of autotransporters are crucial for bacterial pathogenesis, with some remaining attached to the bacterial surface while others are released by proteolysis. An enigma remains as to whether autotransporters should be considered a class of secretion system, or simply a class of substrate with peculiar requirements for their secretion. We sought to establish a sensitive search protocol that could identify and characterize diverse autotransporters from bacterial genome sequence data. The new sequence analysis pipeline identified more than 1500 autotransporter sequences from diverse bacteria, including numerous species of Chlamydiales and Fusobacteria as well as all classes of Proteobacteria. Interrogation of the proteins revealed that there are numerous classes of passenger domains beyond the known proteases, adhesins and esterases. In addition the barrel-domain-a characteristic feature of autotransporters-was found to be composed from seven conserved sequence segments that can be arranged in multiple ways in the tertiary structure of the assembled autotransporter. One of these conserved motifs overlays the targeting information required for autotransporters to reach the outer membrane. Another conserved and diagnostic motif maps to the linker region between the passenger domain and barrel-domain, indicating it as an important feature in the assembly of autotransporters.

  16. Spontaneous bacterial peritonitis - Detection, treatment and prophylaxis in patients with liver cirrhosis

    NARCIS (Netherlands)

    Jansen, PLM

    1997-01-01

    Spontaneous bacterial peritonitis (SBP) is a common complication in patients with liver cirrhosis and ascites. When a patient with liver cirrhosis and ascites presents with fever and/or abdominal pain, or a tender abdomen on physical examination, or with refractory ascites, an ascitic fluid aspirate

  17. System automation for a bacterial colony detection and identification instrument via forward scattering

    International Nuclear Information System (INIS)

    A system design and automation of a microbiological instrument that locates bacterial colonies and captures the forward-scattering signatures are presented. The proposed instrument integrates three major components: a colony locator, a forward scatterometer and a motion controller. The colony locator utilizes an off-axis light source to illuminate a Petri dish and an IEEE1394 camera to capture the diffusively scattered light to provide the number of bacterial colonies and two-dimensional coordinate information of the bacterial colonies with the help of a segmentation algorithm with region-growing. Then the Petri dish is automatically aligned with the respective centroid coordinate with a trajectory optimization method, such as the Traveling Salesman Algorithm. The forward scatterometer automatically computes the scattered laser beam from a monochromatic image sensor via quadrant intensity balancing and quantitatively determines the centeredness of the forward-scattering pattern. The final scattering signatures are stored to be analyzed to provide rapid identification and classification of the bacterial samples

  18. Rapid and sensitive detection of Citrus Bacterial Canker by loop-mediated isothermal amplification combined with simple visual evaluation methods

    Directory of Open Access Journals (Sweden)

    Vojnov Adrian A

    2010-06-01

    Full Text Available Abstract Background Citrus Bacterial Canker (CBC is a major, highly contagious disease of citrus plants present in many countries in Asia, Africa and America, but not in the Mediterranean area. There are three types of Citrus Bacterial Canker, named A, B, and C that have different genotypes and posses variation in host range within citrus species. The causative agent for type A CBC is Xanthomonas citri subsp. citri, while Xanthomonas fuscans subsp. aurantifolii, strain B causes type B CBC and Xanthomonas fuscans subsp. aurantifolii strain C causes CBC type C. The early and accurate identification of those bacteria is essential for the protection of the citrus industry. Detection methods based on bacterial isolation, antibodies or polymerase chain reaction (PCR have been developed previously; however, these approaches may be time consuming, laborious and, in the case of PCR, it requires expensive laboratory equipment. Loop-mediated isothermal amplification (LAMP, which is a novel isothermal DNA amplification technique, is sensitive, specific, fast and requires no specialized laboratory equipment. Results A loop-mediated isothermal amplification assay for the diagnosis of Citrus Bacterial Canker (CBC-LAMP was developed and evaluated. DNA samples were obtained from infected plants or cultured bacteria. A typical ladder-like pattern on gel electrophoresis was observed in all positive samples in contrast to the negative controls. In addition, amplification products were detected by visual inspection using SYBRGreen and using a lateral flow dipstick, eliminating the need for gel electrophoresis. The sensitivity and specificity of the assay were evaluated in different conditions and using several sample sources which included purified DNA, bacterium culture and infected plant tissue. The sensitivity of the CBC-LAMP was 10 fg of pure Xcc DNA, 5 CFU in culture samples and 18 CFU in samples of infected plant tissue. No cross reaction was observed with DNA

  19. Study of train positioning method based on BDS/GSM-R co mbination%基于 BDS/GSM-R 组合列车定位方法的研究

    Institute of Scientific and Technical Information of China (English)

    李卫东; 侯丽虹; 王友生

    2016-01-01

    针对卫星定位容易丢失信号的问题,提出北斗卫星导航技术与 GSM-R 技术相结合的定位方法。根据哈尔滨西至长春铁路线的实测数据,利用 BP 神经网络构造 BDS /GSM-R 定位信息的融合模型,采用遗传算法优化 BP 神经的权值和阈值,对比优化前和优化后的 BDS /GSM-R 组合定位方法。实验结果表明:优化后的 BP 神经网络训练结果与列车实际运行轨迹偏差更小,东向、北向、方位角定位误差的波动范围明显减小,可以保持列车定位的连续性和精确性。%Aiming at the problem that satellite positioning signal is easily lost,the positioning method that com-bine BeiDou satellite navigation technology with GSM-R technology was put forward.According to the measured data from the Harbin West railway station to Changchun,onethe BDS /GSM -R positioning information fusion model was firstly built using BP neural network structure.The BP neural weights and thresholds were optimized using genetic algorithm.Finally,the results before and after optimization of combined BDS /GSM-R positioning method was compared..The results show that the difference between the training results of BP neural network after optimization and the practical operation tracks of train is reduced.The range of error located in the east and northoriention and azimuth error are obviously decreased.This method can keep the continuity and precision of train positioning.

  20. Modeling bacteriophage amplification as a predictive tool for optimized MALDI-TOF MS-based bacterial detection.

    Science.gov (United States)

    Cox, Christopher R; Rees, Jon C; Voorhees, Kent J

    2012-11-01

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a valuable tool for rapid bacterial detection and identification but is limited by the need for relatively high cell count samples, which have been grown under strictly controlled conditions. These requirements can be eliminated by the natural infection of a viable bacterial species of interest with a host-specific phage. This produces a rapid increase in phage protein concentrations in comparison to bacterial concentrations, which can in turn be exploited as a method for signal amplification during MALDI-TOF MS. One drawback to this approach is the requirement for repetitive, time-consuming sample preparation and analysis applied over the course of a phage infection to monitor phage concentrations as a function of time to determine the MALDI-TOF MS detection limit. To reduce the requirement for repeated preparation and analysis, a modified phage therapy model was investigated as a means for predicting the time during a given phage infection when a detectable signal would occur. The modified model used a series of three differential equations composed of predetermined experimental parameters including phage burst size and burst time to predict progeny phage concentrations as a function of time. Using Yersinia pestis with plague diagnostic phage φA1122 and Escherichia coli with phage MS2 as two separate, well-characterized model phage-host pairs, we conducted in silico modeling of the infection process and compared it with experimental infections monitored in real time by MALDI-TOF MS. Significant agreement between mathematically calculated phage growth curves and those experimentally obtained by MALDI-TOF MS was observed, thus verifying this method's utility for significant time and labor reduction.

  1. [Qualitative and quantitative detection of bacterial flora in experimental blind loop syndrome of the rat].

    Science.gov (United States)

    Menge, H; Simes, G; Germer, C T; Wagner, J; Hahn, H; Riecken, E O

    1985-08-01

    In the blind loop syndrome bacterial overgrowth--accompanied by an increase in bile acid deconjugation--is thought to be responsible for the observed morphological alterations of the small intestinal mucosa with its concomitant malabsorption syndrome. Since in this chain of events the bacterial overgrowth is of primary importance, we have performed a complete qualitative and quantitative evaluation of the intraluminal flora in rats with surgically created self-filling blind loops. The results show a significant increase in bacteria of the aerobic growing genera E. coli and Streptococcus (Enterococcus), and of the anaerobic growing genus Bacteroides, in one single rat also of the genera Lactobacillus/Bifidobacterium. In order to elucidate which strains of bacteria are predominantly responsible for the morphological and functional alterations observed in the stagnant loop syndrome, germ-free rats with self-filling blind loops should be contaminated selectively with bacteria of these genera.

  2. Evaluation of a multiplex real-time PCR kit Amplidiag® Bacterial GE in the detection of bacterial pathogens from stool samples.

    Science.gov (United States)

    Rintala, Anniina; Munukka, Eveliina; Weintraub, Andrej; Ullberg, Måns; Eerola, Erkki

    2016-09-01

    This study evaluated the performance of a new commercially available multiplex real-time PCR kit Amplidiag® Bacterial GE in the systematic screening of bacterial pathogens causing gastroenteritis. Stool samples from 1168 patients were analyzed with Amplidiag® Bacterial GE, stool culture, and molecular reference tests, and the sensitivity and specificity of Amplidiag® Bacterial GE were determined by comparing the results to the reference tests. The evaluation showed good performance for Amplidiag® Bacterial GE: sensitivity and specificity of the test was 100/99.7% for Salmonella, 100/99.8% for Yersinia, 98.8/99.2% for Campylobacter, 92.9/100% for Shigella/EIEC, 100/99.9% for EHEC, 92.9/99.8% for ETEC, 98.9/99.2% for EPEC, and 100/99.8% EAEC, respectively. When compared with stool culture, Amplidiag® Bacterial GE was found to be more sensitive. This study suggests that Amplidiag® Bacterial GE is suitable for screening bacterial pathogens from stool samples. However, this study only demonstrates the performance of Amplidiag® Bacterial GE in low endemic settings, as the number of positive findings in this study was relatively low. PMID:27425376

  3. Detection of bacterial contamination and DNA quantification in stored blood units in 2 veterinary hospital blood banks.

    Science.gov (United States)

    Stefanetti, Valentina; Miglio, Arianna; Cappelli, Katia; Capomaccio, Stefano; Sgariglia, Elisa; Marenzoni, Maria L; Antognoni, Maria T; Coletti, Mauro; Mangili, Vittorio; Passamonti, Fabrizio

    2016-09-01

    Blood transfusions in veterinary medicine have become increasingly more common and are now an integral part of lifesaving and advanced treatment in small and large animals. Important risks associated with transfusion of blood products include the transmission of various infectious diseases. Several guidelines suggest what infectious agents to screen for in canine and feline transfusion medicine. However, while the risk of bacterial contamination of blood products during storage and administration has not been documented in veterinary medicine, it has emerged as a cause of morbidity and mortality in human transfusion medicine. Clinical experience shows that the majority of blood component bacterial contaminations are caused by only a few species. Unlike other types of bacteria, psychrotolerant species like Pseudomonas spp. and Serratia spp. can proliferate during the storage of blood units at 4°C from a very low titer at the time of blood collection to a clinically significant level (> 10(5) CFU/mL) causing clinical sepsis resulting from red blood cell concentrate transfusions in human medicine. The purpose of this report was to describe the detection and quantification procedures applied in 4 cases of bacterial contamination of canine and feline blood units, which suggest the need for further investigations to optimize patients' safety in veterinary transfusion medicine. PMID:27642138

  4. Individual growth detection of bacterial species in an in vitro oral polymicrobial biofilm model.

    Science.gov (United States)

    Tabenski, L; Maisch, T; Santarelli, F; Hiller, K-A; Schmalz, G

    2014-11-01

    Most in vitro studies on the antibacterial effects of antiseptics have used planktonic bacteria in monocultures. However, this study design does not reflect the in vivo situation in oral cavities harboring different bacterial species that live in symbiotic relationships in biofilms. The aim of this study was to establish a simple in vitro polymicrobial model consisting of only three bacterial strains of different phases of oral biofilm formation to simulate in vivo oral conditions. Therefore, we studied the biofilm formation of Actinomyces naeslundii (An), Fusobacterium nucleatum (Fn), and Enterococcus faecalis (Ef) on 96-well tissue culture plates under static anaerobic conditions using artificial saliva according to the method established by Pratten et al. that was supplemented with 1 g l(-1) sucrose. Growth was separately determined for each bacterial strain after incubation periods of up to 72 h by means of quantitative real-time polymerase chain reaction and live/dead staining. Presence of an extracellular polymeric substance (EPS) was visualized by Concanavalin A staining. Increasing incubation times of up to 72 h showed adhesion and propagation of the bacterial strains with artificial saliva formulation. An and Ef had significantly higher growth rates than Fn. Live/dead staining showed a median of 49.9 % (range 46.0-53.0 %) of living bacteria after 72 h of incubation, and 3D fluorescence microscopy showed a three-dimensional structure containing EPS. An in vitro oral polymicrobial biofilm model was established to better simulate oral conditions and had the advantage of providing the well-controlled experimental conditions of in vitro testing. PMID:25119373

  5. Bacterial discrimination by means of a universal array approach mediated by LDR (ligase detection reaction

    Directory of Open Access Journals (Sweden)

    Consolandi Clarissa

    2002-09-01

    Full Text Available Abstract Background PCR amplification of bacterial 16S rRNA genes provides the most comprehensive and flexible means of sampling bacterial communities. Sequence analysis of these cloned fragments can provide a qualitative and quantitative insight of the microbial population under scrutiny although this approach is not suited to large-scale screenings. Other methods, such as denaturing gradient gel electrophoresis, heteroduplex or terminal restriction fragment analysis are rapid and therefore amenable to field-scale experiments. A very recent addition to these analytical tools is represented by microarray technology. Results Here we present our results using a Universal DNA Microarray approach as an analytical tool for bacterial discrimination. The proposed procedure is based on the properties of the DNA ligation reaction and requires the design of two probes specific for each target sequence. One oligo carries a fluorescent label and the other a unique sequence (cZipCode or complementary ZipCode which identifies a ligation product. Ligated fragments, obtained in presence of a proper template (a PCR amplified fragment of the 16s rRNA gene contain either the fluorescent label or the unique sequence and therefore are addressed to the location on the microarray where the ZipCode sequence has been spotted. Such an array is therefore "Universal" being unrelated to a specific molecular analysis. Here we present the design of probes specific for some groups of bacteria and their application to bacterial diagnostics. Conclusions The combined use of selective probes, ligation reaction and the Universal Array approach yielded an analytical procedure with a good power of discrimination among bacteria.

  6. Individual growth detection of bacterial species in an in vitro oral polymicrobial biofilm model.

    Science.gov (United States)

    Tabenski, L; Maisch, T; Santarelli, F; Hiller, K-A; Schmalz, G

    2014-11-01

    Most in vitro studies on the antibacterial effects of antiseptics have used planktonic bacteria in monocultures. However, this study design does not reflect the in vivo situation in oral cavities harboring different bacterial species that live in symbiotic relationships in biofilms. The aim of this study was to establish a simple in vitro polymicrobial model consisting of only three bacterial strains of different phases of oral biofilm formation to simulate in vivo oral conditions. Therefore, we studied the biofilm formation of Actinomyces naeslundii (An), Fusobacterium nucleatum (Fn), and Enterococcus faecalis (Ef) on 96-well tissue culture plates under static anaerobic conditions using artificial saliva according to the method established by Pratten et al. that was supplemented with 1 g l(-1) sucrose. Growth was separately determined for each bacterial strain after incubation periods of up to 72 h by means of quantitative real-time polymerase chain reaction and live/dead staining. Presence of an extracellular polymeric substance (EPS) was visualized by Concanavalin A staining. Increasing incubation times of up to 72 h showed adhesion and propagation of the bacterial strains with artificial saliva formulation. An and Ef had significantly higher growth rates than Fn. Live/dead staining showed a median of 49.9 % (range 46.0-53.0 %) of living bacteria after 72 h of incubation, and 3D fluorescence microscopy showed a three-dimensional structure containing EPS. An in vitro oral polymicrobial biofilm model was established to better simulate oral conditions and had the advantage of providing the well-controlled experimental conditions of in vitro testing.

  7. Detection of ureolytic activity of bacterial strains isolated from entomopathogenic nematodes using infrared spectroscopy.

    Science.gov (United States)

    Lechowicz, Lukasz; Chrapek, Magdalena; Czerwonka, Grzegorz; Korzeniowska-Kowal, Agnieszka; Tobiasz, Anna; Urbaniak, Mariusz; Matuska-Lyzwa, Joanna; Kaca, Wieslaw

    2016-08-01

    The pathogenicity of entomopathogenic nematodes (EPNs) depends directly on the presence of bacteria in the nematode digestive tracts. Based on 16S rRNA and MALDI-TOF analyses 20 isolated bacteria were assigned to 10 species with 10 isolates classified as Pseudomonas ssp. Six strains (30%) show ureolytic activity on Christensen medium. Spectroscopic analysis of the strains showed that the ureolytic activity is strongly correlated with the following wavenumbers: 935 cm(-1) in window W4, which carries information about the bacterial cell wall construction and 1158 cm(-1) in window W3 which corresponds to proteins in bacterial cell. A logistic regression model designed on the basis of the selected wavenumbers differentiates ureolytic from non-ureolytic bacterial strains with an accuracy of 100%. Spectroscopic studies and mathematical analyses made it possible to differentiate EPN-associated Pseudomonas sp. strains from clinical Pseudomonas aeruginosa PAO1. These results suggest, that infrared spectra of EPN-associated Pseudomonas sp. strains may reflect its adaptation to the host. PMID:26972384

  8. PMA-Linked Fluorescence for Rapid Detection of Viable Bacterial Endospores

    Science.gov (United States)

    LaDuc, Myron T.; Venkateswaran, Kasthuri; Mohapatra, Bidyut

    2012-01-01

    The most common approach for assessing the abundance of viable bacterial endospores is the culture-based plating method. However, culture-based approaches are heavily biased and oftentimes incompatible with upstream sample processing strategies, which make viable cells/spores uncultivable. This shortcoming highlights the need for rapid molecular diagnostic tools to assess more accurately the abundance of viable spacecraft-associated microbiota, perhaps most importantly bacterial endospores. Propidium monoazide (PMA) has received a great deal of attention due to its ability to differentiate live, viable bacterial cells from dead ones. PMA gains access to the DNA of dead cells through compromised membranes. Once inside the cell, it intercalates and eventually covalently bonds with the double-helix structures upon photoactivation with visible light. The covalently bound DNA is significantly altered, and unavailable to downstream molecular-based manipulations and analyses. Microbiological samples can be treated with appropriate concentrations of PMA and exposed to visible light prior to undergoing total genomic DNA extraction, resulting in an extract comprised solely of DNA arising from viable cells. This ability to extract DNA selectively from living cells is extremely powerful, and bears great relevance to many microbiological arenas.

  9. An Enhanced Box-Wing Solar Radiation pressure model for BDS and initial results

    Science.gov (United States)

    Zhao, Qunhe; Wang, Xiaoya; Hu, Xiaogong; Guo, Rui; Shang, Lin; Tang, Chengpan; Shao, Fan

    2016-04-01

    Solar radiation pressure forces are the largest non-gravitational perturbations acting on GNSS satellites, which is difficult to be accurately modeled due to the complicated and changing satellite attitude and unknown surface material characteristics. By the end of 2015, there are more than 50 stations of the Multi-GNSS Experiment(MGEX) set-up by the IGS. The simple box-plate model relies on coarse assumptions about the dimensions and optical properties of the satellite due to lack of more detailed information. So, a physical model based on BOX-WING model is developed, which is more sophisticated and more detailed physical structure has been taken into account, then calculating pressure forces according to the geometric relations between light rays and surfaces. All the MGEX stations and IGS core stations had been processed for precise orbit determination tests with GPS and BDS observations. Calculation range covers all the two kinds of Eclipsing and non-eclipsing periods in 2015, and we adopted the un-differential observation mode and more accurate values of satellite phase centers. At first, we tried nine parameters model, and then eliminated the parameters with strong correlation between them, came into being five parameters of the model. Five parameters were estimated, such as solar scale, y-bias, three material coefficients of solar panel, x-axis and z-axis panels. Initial results showed that, in the period of yaw-steering mode, use of Enhanced ADBOXW model results in small improvement for IGSO and MEO satellites, and the Root-Mean-Square(RMS) error value of one-day arc orbit decreased by about 10%~30% except for C08 and C14. The new model mainly improved the along track acceleration, up to 30% while in the radial track was not obvious. The Satellite Laser Ranging(SLR) validation showed, however, that this model had higher prediction accuracy in the period of orbit-normal mode, compared to GFZ multi-GNSS orbit products, as well with relative post

  10. BDS Based on the Uses of the Oceans Icebergs Envisaged for the Service of Mankind%基于 BDS 利用海洋上冰山为人类服务的设想

    Institute of Scientific and Technical Information of China (English)

    郭英起; 范国敏; 刘甫斌; 毕继鑫

    2015-01-01

    The ocean iceberg although called 'Ocean killers',but if humans are able to well prepared in advance ,also can use the tip to the service of humanity .This paper ex‐pounds the ocean iceberg characteristics ,and studied the compass navigation satellite system (BDS) based on the assumption of utilization of marine an iceberg in the service of mankind . The research conclusion can also be for future construction of digital ocean to provide refer‐ence .%海洋上冰山虽然被人们称为“海洋杀手”,但是如果人类能够在远航之前做好充分的准备,亦可以利用冰山为人类服务。本文阐述了海洋上冰山的特点,而且研讨了基于北斗卫星导航系统(BDS )利用海洋上冰山为人类服务的设想。本文研讨的结论也可以为以后数字海洋的建设提供参考。

  11. The use of magnetic resonance and MR angiography in the detection of cerebral infarction: A complication of pediatric bacterial meningitis

    Directory of Open Access Journals (Sweden)

    Stošić-Opinćal Tatjana

    2005-01-01

    Full Text Available Bacground. Association of both cerebral infarction and acute bacterial meningitis is more common in younger patients than in the elderly. The rate of mortality and the frequency of sequel are very high inspite of the use of modern antibiotic therapy. In more than 30% of the cases of childhood bacterial meningitis, both arterial and venous infarctions can occur. The aim of this study was to present the role of the use of magnetic resonance (MRI, and MR angiography (MRA in the detection of bacterial meningitis in children complicated with cerebral infarctions. Method. In the Centre for MR, the Clinical Centre of Serbia, 25 patients with the diagnosis of bacterial meningitis, of which 9 children with cerebral infarction whose clinical conditon deteriorated acutely, despite the antibiotic therapy, underwent MRI and MR angiography examination on a 1T scanner. Examination included the conventional spin-echo techniques with T1-weighted saggital and coronal, and T2- weighted axial and coronal images. Coronal fluid attenuated inversion recovery (FLAIR and the postcontrast T1-weighted images in three orthogonal planes were also used. The use MR angiography was accomplished by the three-dimensional time-of-flight (3D TOF technique. Results. The findings included: multiple hemorrhagic infarction in 4 patients, multiple infarctions in 3 patients, focal infarction in 1 patient and diffuse infarction (1 patient. Common sites of involvement were: the frontal lobes, temporal lobes and basal ganglia. The majority of infarctions were bilateral. In 3 of the patients empyema was found, and in 1 patient bitemporal abscess was detected. In 8 of the patients MR angiography confirmed inflammatory vasculitis. Conclusion. Infarction is the most common sequel of severe meningitis in children. Since the complication of cerebral infarction influences the prognosis of meningitis, repetitive MRI examinations are very significant for the evaluation of the time course of

  12. LNA probes substantially improve the detection of bacterial endosymbionts in whole mount of insects by fluorescent in-situ hybridization

    Directory of Open Access Journals (Sweden)

    Priya Natarajan

    2012-05-01

    Full Text Available Abstract Background Detection of unculturable bacteria and their localization in the host, by fluorescent in-situ hybridization (FISH, is a powerful technique in the study of host-bacteria interaction. FISH probes are designed to target the 16 s rRNA region of the bacteria to be detected. LNA probes have recently been used in FISH studies and proven to be more efficient. To date no report has employed LNA probes for FISH detection of bacterial endosymbiont in the whole mount tissues. Further, though speculated, bacteriocytes have not been reported from males of Bemisia tabaci. Results In this study, we compared the efficiency in detecting bacteria by fluorescent DNA oligonucleotides versus modified probes containing Locked Nucleic Acid (LNA substitution in their structure. We used the insect Bemisia tabaci as the experimental material since it carried simultaneous infection by two bacteria: one a primary endosymbiont, Portiera (and present in more numbers while the other a secondary endosymbiont Arsenophonus (and present in less numbers. Thus a variation in the abundance of bacteria was expected. While detecting both the bacteria, we found a significant increase in the signal whenever LNA probes were used. However, the difference was more pronounced in detecting the secondary endosymbiont, wherein DNA probes gave weak signals when compared to LNA probes. Also, signal to noise ratio for LNA probes was higher than DNA probes. We found that LNA considerably improved sensitivity of FISH, as compared to the commonly used DNA oligonucleotide probe. Conclusion By employing LNA probes we could detect endosymbiotic bacteria in males, which have never been reported previously. We were able to detect bacteriocytes containing Portiera and Arsenophonus in the males of B. tabaci. Thus, employing LNA probes at optimized conditions will help to significantly improve detection of bacteria at the lowest concentration and may give a comprehensible depiction

  13. Evaluation of a Multiplex Real-Time PCR Assay for Detecting Major Bacterial Enteric Pathogens in Fecal Specimens: Intestinal Inflammation and Bacterial Load Are Correlated in Campylobacter Infections.

    Science.gov (United States)

    Wohlwend, Nadia; Tiermann, Sacha; Risch, Lorenz; Risch, Martin; Bodmer, Thomas

    2016-09-01

    A total of 1,056 native or Cary-Blair-preserved stool specimens were simultaneously tested by conventional stool culturing and by enteric bacterial panel (EBP) multiplex real-time PCR for Campylobacter jejuni, Campylobacter coli, Salmonella spp., and shigellosis disease-causing agents (Shigella spp. and enteroinvasive Escherichia coli [EIEC]). Overall, 143 (13.5%) specimens tested positive by PCR for the targets named above; 3 coinfections and 109 (10.4%) Campylobacter spp., 17 (1.6%) Salmonella spp., and 20 (1.9%) Shigella spp./EIEC infections were detected. The respective positive stool culture rates were 75 (7.1%), 14 (1.3%), and 7 (0.7%). The median threshold cycle (CT) values of culture-positive specimens were significantly lower than those of culture-negative ones (CT values, 24.3 versus 28.7; P Campylobacter infections, the respective median fecal calprotectin concentrations in PCR-negative/culture-negative (n = 40), PCR-positive/culture-negative (n = 14), and PCR-positive/culture-positive (n = 15) specimens were 134 mg/kg (interquartile range [IQR], 30 to 1,374 mg/kg), 1,913 mg/kg (IQR, 165 to 3,813 mg/kg), and 5,327 mg/kg (IQR, 1,836 to 18,213 mg/kg). Significant differences were observed among the three groups (P Campylobacter spp., Salmonella spp., and Shigella spp./EIEC using the BD Max EBP assay will result in timely diagnosis and improved sensitivity. The determination of inflammatory markers, such as calprotectin, in fecal specimens may aid in the interpretation of PCR results, particularly for enteric pathogens associated with mucosal damage and colonic inflammation. PMID:27307458

  14. Evaluation of leukocyte esterase and nitrite strip tests to detect spontaneous bacterial peritonitis in cirrhotic patients

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To investigate the diagnostic efficacy of leukocyte esterase and nitrite reagent strips for bedside diagnosis of spontaneous bacterial peritonitis (SBP).METHODS: A total of 63 consecutive patients with cirrhotic ascites (38 male, 25 female) tested between April 2005 and July 2006 were included in the study. Bedside reagent strip testing was performed on ascitic fluid and the results compared to manual cell counting and ascitic fluid culture. SBP was defined as having a olymorphonuclear ascites count of ≥ 250/mm3.RESULTS: Fifteen samples showed SBP. The sensitivity,specificity, positive and negative predictive values of the leukocyte esterase reagent strips were; 93%, 100%, 100%, and 98%, respectively. The sensitivity,specificity, positive and negative predictive value of the nitrite reagent strips were 13%, 93%, 40%, and 77%, respectively. The combination of leukocyte esterase and nitrite reagents strips did not yield statistically significant effects on diagnostic accuracy. CONCLUSION: Leukocyte esterase reagent strips may provide a rapid, bedside diagnostic test for SBP.

  15. Detecting bacterial magnetite in sediments: strengths and limitations of FMR spectroscopy

    Science.gov (United States)

    Winklhofer, M.

    2012-04-01

    Ferromagnetic resonance spectroscopy (FMR) is increasingly being used as a diagnostic tool for identifying bacterial magnetite in sediments [e.g., Kopp et al. 2007; Kind et al. 2011, Roberts et al. 2011 ], the reason being that magnetic bacteria have a characteristic FMR fingerprint which is not known from inorganic geological samples [Kopp & Kirschvink, 2008]. The diagnostic FMR features of single-stranded magnetite chains are a g-value 2, quite opposite to what we know from single-stranded chains. Therefore, in order to better understand possible biogenic FMR fingerprints and to refine the screen, there is a clear need to acquire FMR spectra of magnetic bacteria with different chain configurations and, in particular, of greigite producing bacteria.

  16. Quantitative Mass Spectrometry for Bacterial Protein Toxins — A Sensitive, Specific, High-Throughput Tool for Detection and Diagnosis

    Directory of Open Access Journals (Sweden)

    Suzanne Kalb

    2011-03-01

    Full Text Available Matrix-assisted laser-desorption time-of-flight (MALDI-TOF mass spectrometry (MS is a valuable high-throughput tool for peptide analysis. Liquid chromatography electrospray ionization (LC-ESI tandem-MS provides sensitive and specific quantification of small molecules and peptides. The high analytic power of MS coupled with high-specificity substrates is ideally suited for detection and quantification of bacterial enzymatic activities. As specific examples of the MS applications in disease diagnosis and select agent detection, we describe recent advances in the analyses of two high profile protein toxin groups, the Bacillus anthracis toxins and the Clostridium botulinum neurotoxins. The two binary toxins produced by B. anthracis consist of protective antigen (PA which combines with lethal factor (LF and edema factor (EF, forming lethal toxin and edema toxin respectively. LF is a zinc-dependent endoprotease which hydrolyzes specific proteins involved in inflammation and immunity. EF is an adenylyl cyclase which converts ATP to cyclic-AMP. Toxin-specific enzyme activity for a strategically designed substrate, amplifies reaction products which are detected by MALDI-TOF-MS and LC-ESI-MS/MS. Pre-concentration/purification with toxin specific monoclonal antibodies provides additional specificity. These combined technologies have achieved high specificity, ultrasensitive detection and quantification of the anthrax toxins. We also describe potential applications to diseases of high public health impact, including Clostridium difficile glucosylating toxins and the Bordetella pertussis adenylyl cyclase.

  17. Low-fouling surface plasmon resonance biosensor for multi-step detection of foodborne bacterial pathogens in complex food samples.

    Science.gov (United States)

    Vaisocherová-Lísalová, Hana; Víšová, Ivana; Ermini, Maria Laura; Špringer, Tomáš; Song, Xue Chadtová; Mrázek, Jan; Lamačová, Josefína; Scott Lynn, N; Šedivák, Petr; Homola, Jiří

    2016-06-15

    Recent outbreaks of foodborne illnesses have shown that foodborne bacterial pathogens present a significant threat to public health, resulting in an increased need for technologies capable of fast and reliable screening of food commodities. The optimal method of pathogen detection in foods should: (i) be rapid, specific, and sensitive; (ii) require minimum sample preparation; and (iii) be robust and cost-effective, thus enabling use in the field. Here we report the use of a SPR biosensor based on ultra-low fouling and functionalizable poly(carboxybetaine acrylamide) (pCBAA) brushes for the rapid and sensitive detection of bacterial pathogens in crude food samples utilizing a three-step detection assay. We studied both the surface resistance to fouling and the functional capabilities of these brushes with respect to each step of the assay, namely: (I) incubation of the sensor with crude food samples, resulting in the capture of bacteria by antibodies immobilized to the pCBAA coating, (II) binding of secondary biotinylated antibody (Ab2) to previously captured bacteria, and (III) binding of streptavidin-coated gold nanoparticles to the biotinylated Ab2 in order to enhance the sensor response. We also investigated the effects of the brush thickness on the biorecognition capabilities of the gold-grafted functionalized pCBAA coatings. We demonstrate that pCBAA-compared to standard low-fouling OEG-based alkanethiolate self-assemabled monolayers-exhibits superior surface resistance regarding both fouling from complex food samples as well as the non-specific binding of S-AuNPs. We further demonstrate that a SPR biosensor based on a pCBAA brush with a thickness as low as 20 nm was capable of detecting E. coli O157:H7 and Salmonella sp. in complex hamburger and cucumber samples with extraordinary sensitivity and specificity. The limits of detection for the two bacteria in cucumber and hamburger extracts were determined to be 57 CFU/mL and 17 CFU/mL for E. coli and 7.4 × 10

  18. A locked nucleic acid (LNA-based real-time PCR assay for the rapid detection of multiple bacterial antibiotic resistance genes directly from positive blood culture.

    Directory of Open Access Journals (Sweden)

    Lingxiang Zhu

    Full Text Available Bacterial strains resistant to various antibiotic drugs are frequently encountered in clinical infections, and the rapid identification of drug-resistant strains is highly essential for clinical treatment. We developed a locked nucleic acid (LNA-based quantitative real-time PCR (LNA-qPCR method for the rapid detection of 13 antibiotic resistance genes and successfully used it to distinguish drug-resistant bacterial strains from positive blood culture samples. A sequence-specific primer-probe set was designed, and the specificity of the assays was assessed using 27 ATCC bacterial strains and 77 negative blood culture samples. No cross-reaction was identified among bacterial strains and in negative samples, indicating 100% specificity. The sensitivity of the assays was determined by spiking each bacterial strain into negative blood samples, and the detection limit was 1-10 colony forming units (CFU per reaction. The LNA-qPCR assays were first applied to 72 clinical bacterial isolates for the identification of known drug resistance genes, and the results were verified by the direct sequencing of PCR products. Finally, the LNA-qPCR assays were used for the detection in 47 positive blood culture samples, 19 of which (40.4% were positive for antibiotic resistance genes, showing 91.5% consistency with phenotypic susceptibility results. In conclusion, LNA-qPCR is a reliable method for the rapid detection of bacterial antibiotic resistance genes and can be used as a supplement to phenotypic susceptibility testing for the early detection of antimicrobial resistance to allow the selection of appropriate antimicrobial treatment and to prevent the spread of resistant isolates.

  19. Fluorescence In Situ Hybridization for the Tissue Detection of Bacterial Pathogens Associated with Porcine Infections

    DEFF Research Database (Denmark)

    Elvang Jensen, Henrik; Jensen, Louise Kruse; Barington, Kristiane;

    2015-01-01

    Fluorescence in situ hybridization (FISH) is an efficient technique for the identification of specific bacteria in tissue of both experimental and spontaneous infections. The method detects specific sequences of nucleic acids by hybridization of fluorescently labeled probes to complementary targe...

  20. Hybrid Bacterial Foraging and Particle Swarm Optimization for detecting Bundle Branch Block

    OpenAIRE

    Kora, Padmavathi; Kalva, Sri Ramakrishna

    2015-01-01

    Abnormal cardiac beat identification is a key process in the detection of heart diseases. Our present study describes a procedure for the detection of left and right bundle branch block (LBBB and RBBB) Electrocardiogram (ECG) patterns. The electrical impulses that control the cardiac beat face difficulty in moving inside the heart. This problem is termed as bundle branch block (BBB). BBB makes it harder for the heart to pump blood effectively through the heart circulatory system. ECG feature ...

  1. Shear horizontal surface acoustic wave microsensor for Class A viral and bacterial detection.

    Energy Technology Data Exchange (ETDEWEB)

    Branch, Darren W.; Huber, Dale L.; Brozik, Susan Marie; Edwards, Thayne L.

    2008-10-01

    The rapid autonomous detection of pathogenic microorganisms and bioagents by field deployable platforms is critical to human health and safety. To achieve a high level of sensitivity for fluidic detection applications, we have developed a 330 MHz Love wave acoustic biosensor on 36{sup o} YX Lithium Tantalate (LTO). Each die has four delay-line detection channels, permitting simultaneous measurement of multiple analytes or for parallel detection of single analyte containing samples. Crucial to our biosensor was the development of a transducer that excites the shear horizontal (SH) mode, through optimization of the transducer, minimizing propagation losses and reducing undesirable modes. Detection was achieved by comparing the reference phase of an input signal to the phase shift from the biosensor using an integrated electronic multi-readout system connected to a laptop computer or PDA. The Love wave acoustic arrays were centered at 330 MHz, shifting to 325-328 MHz after application of the silicon dioxide waveguides. The insertion loss was -6 dB with an out-of-band rejection of 35 dB. The amplitude and phase ripple were 2.5 dB p-p and 2-3{sup o} p-p, respectively. Time-domain gating confirmed propagation of the SH mode while showing suppression of the triple transit. Antigen capture and mass detection experiments demonstrate a sensitivity of 7.19 {+-} 0.74{sup o} mm{sup 2}/ng with a detection limit of 6.7 {+-} 0.40 pg/mm{sup 2} for each channel.

  2. Automated Image Analysis for the Detection of Benthic Crustaceans and Bacterial Mat Coverage Using the VENUS Undersea Cabled Network

    Directory of Open Access Journals (Sweden)

    Jacopo Aguzzi

    2011-11-01

    Full Text Available The development and deployment of sensors for undersea cabled observatories is presently biased toward the measurement of habitat variables, while sensor technologies for biological community characterization through species identification and individual counting are less common. The VENUS cabled multisensory network (Vancouver Island, Canada deploys seafloor camera systems at several sites. Our objective in this study was to implement new automated image analysis protocols for the recognition and counting of benthic decapods (i.e., the galatheid squat lobster, Munida quadrispina, as well as for the evaluation of changes in bacterial mat coverage (i.e., Beggiatoa spp., using a camera deployed in Saanich Inlet (103 m depth. For the counting of Munida we remotely acquired 100 digital photos at hourly intervals from 2 to 6 December 2009. In the case of bacterial mat coverage estimation, images were taken from 2 to 8 December 2009 at the same time frequency. The automated image analysis protocols for both study cases were created in MatLab 7.1. Automation for Munida counting incorporated the combination of both filtering and background correction (Median- and Top-Hat Filters with Euclidean Distances (ED on Red-Green-Blue (RGB channels. The Scale-Invariant Feature Transform (SIFT features and Fourier Descriptors (FD of tracked objects were then extracted. Animal classifications were carried out with the tools of morphometric multivariate statistic (i.e., Partial Least Square Discriminant Analysis; PLSDA on Mean RGB (RGBv value for each object and Fourier Descriptors (RGBv+FD matrices plus SIFT and ED. The SIFT approach returned the better results. Higher percentages of images were correctly classified and lower misclassification errors (an animal is present but not detected occurred. In contrast, RGBv+FD and ED resulted in a high incidence of records being generated for non-present animals. Bacterial mat coverage was estimated in terms of Percent

  3. Performance of BVBlue Rapid Test in Detecting Bacterial Vaginosis among Women in Mysore, India

    Directory of Open Access Journals (Sweden)

    Purnima Madhivanan

    2014-01-01

    Full Text Available Bacterial vaginosis (BV is the most common cause of abnormal vaginal discharge in reproductive age women. It is associated with increased susceptibility to HIV/STI and adverse birth outcomes. Diagnosis of BV in resource-poor settings like India is challenging. With little laboratory infrastructure there is a need for objective point-of-care diagnostic tests. Vaginal swabs were collected from women 18 years and older, with a vaginal pH > 4.5 attending a reproductive health clinic. BV was diagnosed with Amsel’s criteria, Nugent scores, and the OSOM BVBlue test. Study personnel were blinded to test results. There were 347 participants enrolled between August 2009 and January 2010. BV prevalence was 45.1% (95% confidence interval (CI: 41.5%–52.8% according to Nugent score. When compared with Nugent score, the sensitivity, specificity, positive predictive value, negative predictive value for Amsel’s criteria and BVBlue were 61.9%, 88.3%, 81.5%, 73.7% and 38.1%, 92.7%, 82.1%, 63.9%, respectively. Combined with a “whiff” test, the performance of BVBlue increased sensitivity to 64.4% and negative predictive value to 73.8%. Despite the good specificity, poor sensitivity limits the usefulness of the BVBlue as a screening test in this population. There is a need to examine the usefulness of this test in other Indian populations.

  4. Development of a real-time PCR method for the detection of bacterial colonization in rat models of severe acute pancreatitis

    Institute of Scientific and Technical Information of China (English)

    PENG Jun-sheng; LIU Zhong-hui; LI Chu-jun; WU Xiao-bin; DIAO De-chang; DU Yan-ping; CHEN Jun-rong; LI Yun; WANG Hua-she

    2010-01-01

    Background Techniques for the fast and accurate detection of bacterial infection are critical for early diagnosis, prevention and treatment of bacterial translocation in clinical severe acute pancreatitis (SAP). In this study, the availability of a real-time PCR method in detection of bacterial colonization in SAP rat models was investigated.Methods Samples of blood, mesenteric lymph nodes (MLN), pancreas and liver from 24 specific pathogen-free rats (8 in a control group, 16 in a SAP group) were detected for bacterial infection rates both by agar plate culture and a real-time PCR method, and the results were made contrast.Results Bacterial infection rates of the blood, MLN, pancreas and liver in the SAP group and the control group by the two different methods were almost the same, which were 5/16, 12/16, 15/16, 12/16 in the SAP group compared with 0/8, 1/8, 0/8, 0/8 in the control group by agar plate culture, while 5/16, 10/16, 13/16, 12/16 and 0/8, 1/8, 0/8, 0/8 respectively by a real-time PCR method. Bacterial number was estimated by real-time PCR, which showed that in the same mass of tissues, the pancreas contained more bacteria than the other three kinds of organs in SAP rats (P <0.01), that may be due to the edema, necrosis and hemorrhage existing in the pancreas, making it easier for bacteria to invade and breed.Conclusion Fast and accurate detection of bacterial translocation in SAP rat models could be carried out by a real-time PCR procedure.

  5. Detection of traces of tetracyclines from fish with a bioluminescent sensor strain incorporating bacterial luciferase reporter genes.

    Science.gov (United States)

    Pellinen, Teijo; Bylund, Göran; Virta, Marko; Niemi, Anneli; Karp, Matti

    2002-08-14

    Bioluminescent Escherichia coli K-12 strain for the specific detection of the tetracycline family of antimicrobial agents was optimized to work with fish samples. The biosensing strain contains a plasmid incorporating the bacterial luciferase operon of Photorhabdus luminescens under the control of the tetracycline responsive element from transposon Tn10 (Korpela et al. Anal. Chem. 1998, 70, 4457-4462). The extraction procedure of oxytetracycline from rainbow trout (Oncorhynchus mykiss) tissue was optimized. There was neither need for centrifugation of homogenized tissue nor use of organic solvents. The lowest levels of detection of tetracycline and oxytetracycline from spiked fish tissue were 20 and 50 microg/kg, respectively, in a 2-h assay. The optimized assay protocol was tested with fish that were given a single oral dose of high and low concentrations of oxytetracycline. The assay was able to detect oxytetracycline residues below the European Union maximum residue limits, and the results correlated well with those obtained by conventional HPLC (R = 0.81). PMID:12166964

  6. Development of internally controlled duplex real-time NASBA diagnostics assays for the detection of microorganisms associated with bacterial meningitis.

    Science.gov (United States)

    Clancy, Eoin; Coughlan, Helena; Higgins, Owen; Boo, Teck Wee; Cormican, Martin; Barrett, Louise; Smith, Terry J; Reddington, Kate; Barry, Thomas

    2016-08-01

    Three duplex molecular beacon based real-time Nucleic Acid Sequence Based Amplification (NASBA) assays have been designed and experimentally validated targeting RNA transcripts for the detection and identification of Haemophilus influenzae, Neisseria meningitidis and Streptococcus pneumoniae respectively. Each real-time NASBA diagnostics assay includes an endogenous non-competitive Internal Amplification Control (IAC) to amplify the splice variant 1 mRNA of the Homo sapiens TBP gene from human total RNA. All three duplex real-time NASBA diagnostics assays were determined to be 100% specific for the target species tested for. Also the Limits of Detection (LODs) for the H. influenzae, N. meningitidis and S. pneumoniae duplex real-time NASBA assays were 55.36, 0.99, and 57.24 Cell Equivalents (CE) respectively. These robust duplex real-time NASBA diagnostics assays have the potential to be used in a clinical setting for the rapid (<60min) specific detection and identification of the most prominent microorganisms associated with bacterial meningitis in humans. PMID:27319375

  7. Performance analysis on carrier phase-based tightly-coupled GPS/BDS/INS integration in GNSS degraded and denied environments.

    Science.gov (United States)

    Han, Houzeng; Wang, Jian; Wang, Jinling; Tan, Xinglong

    2015-04-14

    The integration of Global Navigation Satellite Systems (GNSS) carrier phases with Inertial Navigation System (INS) measurements is essential to provide accurate and continuous position, velocity and attitude information, however it is necessary to fix ambiguities rapidly and reliably to obtain high accuracy navigation solutions. In this paper, we present the notion of combining the Global Positioning System (GPS), the BeiDou Navigation Satellite System (BDS) and low-cost micro-electro-mechanical sensors (MEMS) inertial systems for reliable navigation. An adaptive multipath factor-based tightly-coupled (TC) GPS/BDS/INS integration algorithm is presented and the overall performance of the integrated system is illustrated. A twenty seven states TC GPS/BDS/INS model is adopted with an extended Kalman filter (EKF), which is carried out by directly fusing ambiguity fixed double-difference (DD) carrier phase measurements with the INS predicted pseudoranges to estimate the error states. The INS-aided integer ambiguity resolution (AR) strategy is developed by using a dynamic model, a two-step estimation procedure is applied with adaptively estimated covariance matrix to further improve the AR performance. A field vehicular test was carried out to demonstrate the positioning performance of the combined system. The results show the TC GPS/BDS/INS system significantly improves the single-epoch AR reliability as compared to that of GPS/BDS-only or single satellite navigation system integrated strategy, especially for high cut-off elevations. The AR performance is also significantly improved for the combined system with adaptive covariance matrix in the presence of low elevation multipath related to the GNSS-only case. A total of fifteen simulated outage tests also show that the time to relock of the GPS/BDS signals is shortened, which improves the system availability. The results also indicate that TC integration system achieves a few centimeters accuracy in positioning based

  8. Performance Analysis on Carrier Phase-Based Tightly-Coupled GPS/BDS/INS Integration in GNSS Degraded and Denied Environments

    Directory of Open Access Journals (Sweden)

    Houzeng Han

    2015-04-01

    Full Text Available The integration of Global Navigation Satellite Systems (GNSS carrier phases with Inertial Navigation System (INS measurements is essential to provide accurate and continuous position, velocity and attitude information, however it is necessary to fix ambiguities rapidly and reliably to obtain high accuracy navigation solutions. In this paper, we present the notion of combining the Global Positioning System (GPS, the BeiDou Navigation Satellite System (BDS and low-cost micro-electro-mechanical sensors (MEMS inertial systems for reliable navigation. An adaptive multipath factor-based tightly-coupled (TC GPS/BDS/INS integration algorithm is presented and the overall performance of the integrated system is illustrated. A twenty seven states TC GPS/BDS/INS model is adopted with an extended Kalman filter (EKF, which is carried out by directly fusing ambiguity fixed double-difference (DD carrier phase measurements with the INS predicted pseudoranges to estimate the error states. The INS-aided integer ambiguity resolution (AR strategy is developed by using a dynamic model, a two-step estimation procedure is applied with adaptively estimated covariance matrix to further improve the AR performance. A field vehicular test was carried out to demonstrate the positioning performance of the combined system. The results show the TC GPS/BDS/INS system significantly improves the single-epoch AR reliability as compared to that of GPS/BDS-only or single satellite navigation system integrated strategy, especially for high cut-off elevations. The AR performance is also significantly improved for the combined system with adaptive covariance matrix in the presence of low elevation multipath related to the GNSS-only case. A total of fifteen simulated outage tests also show that the time to relock of the GPS/BDS signals is shortened, which improves the system availability. The results also indicate that TC integration system achieves a few centimeters accuracy in

  9. Performance analysis on carrier phase-based tightly-coupled GPS/BDS/INS integration in GNSS degraded and denied environments.

    Science.gov (United States)

    Han, Houzeng; Wang, Jian; Wang, Jinling; Tan, Xinglong

    2015-01-01

    The integration of Global Navigation Satellite Systems (GNSS) carrier phases with Inertial Navigation System (INS) measurements is essential to provide accurate and continuous position, velocity and attitude information, however it is necessary to fix ambiguities rapidly and reliably to obtain high accuracy navigation solutions. In this paper, we present the notion of combining the Global Positioning System (GPS), the BeiDou Navigation Satellite System (BDS) and low-cost micro-electro-mechanical sensors (MEMS) inertial systems for reliable navigation. An adaptive multipath factor-based tightly-coupled (TC) GPS/BDS/INS integration algorithm is presented and the overall performance of the integrated system is illustrated. A twenty seven states TC GPS/BDS/INS model is adopted with an extended Kalman filter (EKF), which is carried out by directly fusing ambiguity fixed double-difference (DD) carrier phase measurements with the INS predicted pseudoranges to estimate the error states. The INS-aided integer ambiguity resolution (AR) strategy is developed by using a dynamic model, a two-step estimation procedure is applied with adaptively estimated covariance matrix to further improve the AR performance. A field vehicular test was carried out to demonstrate the positioning performance of the combined system. The results show the TC GPS/BDS/INS system significantly improves the single-epoch AR reliability as compared to that of GPS/BDS-only or single satellite navigation system integrated strategy, especially for high cut-off elevations. The AR performance is also significantly improved for the combined system with adaptive covariance matrix in the presence of low elevation multipath related to the GNSS-only case. A total of fifteen simulated outage tests also show that the time to relock of the GPS/BDS signals is shortened, which improves the system availability. The results also indicate that TC integration system achieves a few centimeters accuracy in positioning based

  10. Detection of bacterial species involved in perimplantitis concerned with cultural and RT-PCR

    Directory of Open Access Journals (Sweden)

    Marcello Gatti

    2010-06-01

    Full Text Available Dental implants offer new treatment options for edentulous either partially or completely, now represent a viable alternative to conventional fixed protheses. Dental implants are colonized by a flora dominated by Gram-positive facultative aerobic, while in patients with bone loss and formation of pockets peri-implant diseases was found a significant difference in the composition of microflora, bacteria, Gram-negative anaerobes in particular Fusobacterium spp., Treponema denticola (Spirochetes, Tannerella forsythensis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia as interim black-pigmented bacteria, Porphyromonas gingivalis, often in high concentrations. Aims. The purpose of this study was to identify those at risk of perimplantitis using 2 techniques: RT-PCR examination of trade and culture. The results were compared taking into consideration the advantages and disadvantages of both methods. Materials and methods.We studied 24 patients (14 women and 10 men, aged, women between 43 and 76 years, with an average of 63.8 + / - 10.9 years, men between 45 and 88 years with a average of 64.3 years + / - 12.5 years. Was performed a double levy of sub-gingival plaque at multiple sites that had an implant CAL (clinical attachment level> 4mm in order to assess the microbiological identification with the two techniques: Examining culture and Real-Time PCR of Commerce ( Gum-Sunstar that identifies 4 bacterial species: A. actinomycetemcomitans (A.a., P.gingivalis (P.g., T.forsythensis (T.f., and T.denticola (T.d.. Results. All patients studied were positive to both tests with charger high: the consideration of tenure, with CFU / ml > 105, was positive in 66.6% of samples by:T.f., and P.g., in 12.5% for A.a., while T.d. not been sought by examining culture, the RT-PCR was positive, with high loads, in 95.8% of samples for T.f., in 79.1% for P.g., in 12.5% for A.a. and 20.8% for T.d.The test crop showed the presence of even P.intermedia in 91

  11. Microbial Diagnostic Microarrays for the Detection and Typing of Food- and Water-Borne (Bacterial) Pathogens.

    Science.gov (United States)

    Kostić, Tanja; Sessitsch, Angela

    2011-10-14

    Reliable and sensitive pathogen detection in clinical and environmental (including food and water) samples is of greatest importance for public health. Standard microbiological methods have several limitations and improved alternatives are needed. Most important requirements for reliable analysis include: (i) specificity; (ii) sensitivity; (iii) multiplexing potential; (iv) robustness; (v) speed; (vi) automation potential; and (vii) low cost. Microarray technology can, through its very nature, fulfill many of these requirements directly and the remaining challenges have been tackled. In this review, we attempt to compare performance characteristics of the microbial diagnostic microarrays developed for the detection and typing of food and water pathogens, and discuss limitations, points still to be addressed and issues specific for the analysis of food, water and environmental samples.

  12. Microbial Diagnostic Microarrays for the Detection and Typing of Food- and Water-Borne (Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Tanja Kostić

    2011-10-01

    Full Text Available Reliable and sensitive pathogen detection in clinical and environmental (including food and water samples is of greatest importance for public health. Standard microbiological methods have several limitations and improved alternatives are needed. Most important requirements for reliable analysis include: (i specificity; (ii sensitivity; (iii multiplexing potential; (iv robustness; (v speed; (vi automation potential; and (vii low cost. Microarray technology can, through its very nature, fulfill many of these requirements directly and the remaining challenges have been tackled. In this review, we attempt to compare performance characteristics of the microbial diagnostic microarrays developed for the detection and typing of food and water pathogens, and discuss limitations, points still to be addressed and issues specific for the analysis of food, water and environmental samples.

  13. Template reporter bacteriophage platform and multiple bacterial detection assays based thereon

    Science.gov (United States)

    Goodridge, Lawrence (Inventor)

    2007-01-01

    The invention is a method for the development of assays for the simultaneous detection of multiple bacteria. A bacteria of interest is selected. A host bacteria containing plasmid DNA from a T even bacteriophage that infects the bacteria of interest is infected with T4 reporter bacteriophage. After infection, the progeny bacteriophage are plating onto the bacteria of interest. The invention also includes single-tube, fast and sensitive assays which utilize the novel method.

  14. Molecular detection of bacterial and parasitic pathogens in hard ticks from Portugal.

    Science.gov (United States)

    Maia, Carla; Ferreira, Andreia; Nunes, Mónica; Vieira, Maria Luísa; Campino, Lenea; Cardoso, Luís

    2014-06-01

    Ticks are important vector arthropods of human and animal pathogens. As information about agents of disease circulating in vectors in Portugal is limited, the aim of the present study was to detect bacteria and parasites with veterinary and zoonotic importance in ticks collected from dogs, cats, and field vegetation. A total of 925 ticks, comprising 888 (96.0%) adults, 8 (0.9%) nymphs, and 29 (3.1%) larvae, were collected in 4 geographic areas (districts) of Portugal. Among those, 620 (67.0%) were removed from naturally infested dogs, 42 (4.5%) from cats, and 263 (28.4%) were questing ticks obtained from field vegetation. Rhipicephalus sanguineus was the predominant tick species, and the only one collected from dogs and vegetation, while all Ixodes ricinus specimens (n=6) were recovered from cats. Rickettsia massiliae and Rickettsia conorii were identified in 35 ticks collected from cats and dogs and in 3 ticks collected from dogs. Among ticks collected from cats or dogs, 4 Rh. sanguineus specimens were detected with Hepatozoon felis, 3 with Anaplasma platys, 2 with Hepatozoon canis, one with Anaplasma phagocytophilum, one with Babesia vogeli, one with Borrelia burgdorferi sensu lato and one with Cercopithifilaria spp. Rickettsia helvetica was detected in one I. ricinus tick collected from a cat. To the best of our knowledge, this was the first time that Cercopithifilaria spp., Ba. vogeli, H. canis, and H. felis have been detected in ticks from Portugal. The wide range of tick-borne pathogens identified, some of zoonotic concern, suggests a risk for the emergence of tick-borne diseases in domestic animals and humans in Portugal. Further studies on these and other tick-borne agents should be performed to better understand their epidemiological and clinical importance, and to support the implementation of effective control measures.

  15. A geometry-free and ionosphere-free multipath mitigation method for BDS three-frequency ambiguity resolution

    Science.gov (United States)

    Chen, Dezhong; Ye, Shirong; Xia, Jingchao; Liu, Yanyan; Xia, Pengfei

    2016-08-01

    Because of the unknown systematic errors and special satellite constellations in the Beidou system (BDS), it is difficult to quickly and reliably determine the ambiguity over long-range baselines in continuously operating reference station (CORS) network. This study seeks to improve the effectiveness and reliability of BDS ambiguity resolution (AR) by combining the geometry-free and ionosphere-free (GFIF) combination and multipath mitigation algorithm. The GFIF combination composed with three-frequency signals is free of distance-dependent errors and can be used to determine the narrow lane ambiguity. The presence of multipath errors means that not all ambiguities can be correctly achieved by rounding the averaged GFIF ambiguity series. A multipath model of the single-differenced (SD) GFIF combination from the previous period is established for each individual satellite. This model is subtracted from the SD GFIF combination for the current day to remove the effects of multipath errors. Using three triangle networks with lengths of approximately 120, 80 and 50 km, we demonstrate that the proposed method improves the AR performance. The ambiguity averaged first fixing time is typically less than 1801 s for inclined geosynchronous orbit (IGSO) and medium earth orbit (MEO) satellites and less than 2007 s for the ˜ 42° elevation geostationary earth orbit (GEO) C02 satellite. However, it is more time consuming for the low-elevation GEO satellites C04 (˜ 18°) and C05 (˜ 28°). Kalman filtering is used to estimate the troposphere delays and two unfixed ambiguities by employing the ionosphere-free observations of all ambiguity-fixed/unfixed satellites. The experimental results show that only tens of seconds are required for AR in around 90 km baselines.

  16. Easiness of Use and Validity Testing of VS-SENSE Device for Detection of Abnormal Vaginal Flora and Bacterial Vaginosis

    Directory of Open Access Journals (Sweden)

    Gilbert G. G. Donders

    2010-01-01

    Full Text Available Accessing vaginal pH is fundamental during gynaecological visit for the detection of abnormal vaginal flora (AVF, but use of pH strips may be time-consuming and difficult to interpret. The aim of this study was to evaluate the VS-SENSE test (Common Sense Ltd, Caesarea, Israel as a tool for the diagnosis of AVF and its correlation with abnormal pH and bacterial vaginosis (BV. The study population consisted of 45 women with vaginal pH ≥ 4.5 and 45 women with normal pH. Vaginal samples were evaluated by VS-SENSE test, microscopy and microbiologic cultures. Comparing with pH strips results, VS-SENSE test specificity was 97.8% and sensitivity of 91%. All severe cases of BV and aerobic vaginitis (AV were detected by the test. Only one case with normal pH had an unclear result. Concluding, VS-SENSE test is easy to perform, and it correlates with increased pH, AVF, and the severe cases of BV and AV.

  17. Detection of bacterial endotoxin in food: New planar interdigital sensors based approach

    KAUST Repository

    Abdul Rahman, Mohd Syaifudin

    2013-02-01

    Food poisoning caused by endotoxins or Lipopolysaccharide (LPS) are associated with Gram-negative bacteria. Two major food-borne pathogens, Escherichia coli and Salmonella are examples of Gram-negative bacteria which cause a large number of outbreaks of food poisoning. New types of planar interdigital sensors have been fabricated with different coating materials to assess their response to endotoxins. A carboxyl-functional polymer, APTES (3-Aminopropyltriethoxysilane) and Thionine were chosen to be coated onto FR4 interdigital sensors. The chosen coating materials have carboxylic or amine functional groups, which were optimized to be stable in water. All coated sensors were immobilized with PmB (Polymyxin B) which has specific binding properties to LPS. The sensors were tested with different concentrations of LPS O111:B4, ranging from 0.1 to 1000 μg/ml. Analyses of sensors\\' performance were based on the impedance spectroscopy method. The impedance spectra were modeled using a constant phase-element (CPE) equivalent circuit, and a principal component analysis (PCA) was used for data classification. Sensor coated with APTES has shown better selectivity for LPS detection. The experiments were repeated by coating APTES and immobilizing PmB to a new improve designed of novel interdigital sensors (thin film silicon based sensors). These sensors were observed to have better sensitivity and selectivity to the target biomolecules of LPS. Further experiments were conducted to study the effect of different coating thickness on sensor sensitivity, selectivity and stability. Different food samples contaminated with endotoxin were also tested to verify that the interdigital sensing approach is able to be used for endotoxin detection. © 2012 Elsevier Ltd. All rights reserved.

  18. Detection of bacterial infection of agave plants by laser-induced fluorescence

    Science.gov (United States)

    Cervantes-Martinez, Jesus; Flores-Hernandez, Ricardo; Rodriguez-Garay, Benjamin; Santacruz-Ruvalcaba, Fernando

    2002-05-01

    Greenhouse-grown plants of Agave tequilana Weber var. azul were inoculated with Erwinia carotovora, the causal agent of stem soft rot. We investigated the laser-induced fluorescence (LIF) of agave plants to determine whether LIF can be used as a noninvasive sensing tool for pathological studies. The LIF technique was also investigated as a means of detecting the effect of the polyamine biosynthesis inhibitor beta-hydroxyethylhydrazine as a bactericide against the pathogenic bacterium Erwinia carotovora. A He-Ne laser at 632.8 nm was used as the excitation source, and in vivo fluorescence emission spectra were recorded in the 660-790-range. Fluorescence maxima were at 690 and 740 nm. The infected plants that were untreated with the bactericide showed a definite increase in fluorescence intensity at both maxima within the first three days after infection. Beginning on the fifth day, a steady decrease in fluorescence intensity was observed, with a greater effect at 740 than at 690 nm. After 30 days there was no fluorescence. The infected plants that had been treated with the bactericide showed no significant change in fluorescence compared with that of the uninfected plants. The ratio of fluorescence intensities was determined to be F 690 nm/F 740 nm for all treatments. These studies indicate that LIF measurements of agave plants may be used for the early detection of certain types of disease and for determining the effect of a bactericide on bacteria. The results also showed that fluorescence intensity ratios can be used as a reliable indicator of the progress of disease.

  19. Remote detection of human toxicants in real time using a human-optimized, bioluminescent bacterial luciferase gene cassette bioreporter

    Science.gov (United States)

    Close, Dan; Webb, James; Ripp, Steven; Patterson, Stacey; Sayler, Gary

    2012-06-01

    Traditionally, human toxicant bioavailability screening has been forced to proceed in either a high throughput fashion using prokaryotic or lower eukaryotic targets with minimal applicability to humans, or in a more expensive, lower throughput manner that uses fluorescent or bioluminescent human cells to directly provide human bioavailability data. While these efforts are often sufficient for basic scientific research, they prevent the rapid and remote identification of potentially toxic chemicals required for modern biosecurity applications. To merge the advantages of high throughput, low cost screening regimens with the direct bioavailability assessment of human cell line use, we re-engineered the bioluminescent bacterial luciferase gene cassette to function autonomously (without exogenous stimulation) within human cells. Optimized cassette expression provides for fully endogenous bioluminescent production, allowing continuous, real time monitoring of the bioavailability and toxicology of various compounds in an automated fashion. To access the functionality of this system, two sets of bioluminescent human cells were developed. The first was programed to suspend bioluminescent production upon toxicological challenge to mimic the non-specific detection of a toxicant. The second induced bioluminescence upon detection of a specific compound to demonstrate autonomous remote target identification. These cells were capable of responding to μM concentrations of the toxicant n-decanal, and allowed for continuous monitoring of cellular health throughout the treatment process. Induced bioluminescence was generated through treatment with doxycycline and was detectable upon dosage at a 100 ng/ml concentration. These results demonstrate that leveraging autonomous bioluminescence allows for low-cost, high throughput direct assessment of toxicant bioavailability.

  20. Towards Single-Shot Detection of Bacterial Endospores via Coherent Raman Spectroscopy

    Science.gov (United States)

    Pestov, Dmitry; Wang, Xi; Ariunbold, Gombojav; Murawski, Robert; Sautenkov, Vladimir; Sokolov, Alexei; Scully, Marlan

    2007-10-01

    Recent advances in coherent anti-Stokes Raman scattering (CARS) spectroscopy hold exciting promise to make the most out of now readily available ultrafast laser sources. Techniques have been devised to mitigate the nonresonant four-wave-mixing in favor of informative Raman-resonant signal. In particular, a hybrid technique for CARS (see Science 316, 265 (2007)) brings together the advantages of coherent broadband pump-Stokes excitation of molecular vibrations and their time-delayed but frequency-resolved probing via a spectrally narrowed and shaped laser pulse. We apply this technique to the problem of real-time detection of warfare bioagents and report single-shot acquisition of a distinct CARS spectrum from a small volume of B. subtilis endospores (˜10^4 spores), a harmless surrogate for B. anthracis. We study the dependence of the CARS signal on the energy of the ultrashort preparation pulses and find the limit on the pulse energy fluence (˜0.2 J/cm^2), imposed by the laser-induced damage of the spores.

  1. Efficacy of coating activated carbon with milk proteins to prevent binding of bacterial cells from foods for PCR detection.

    Science.gov (United States)

    Opet, Nathan J; Levin, Robert E

    2013-08-01

    Foods contaminated with pathogens are common sources of illness. Currently, the most common and sensitive rapid detection method involves the PCR. However, food matrices are complex and contain inhibitors that limit the sensitivity of the PCR. The use of coated activated carbon can effectively facilitate the removal of PCR inhibitors without binding targeted bacterial cells from food samples. With the use of activated carbon coated with milk proteins, a cell recovery at pH 7.0 of 95.7%±2.0% was obtained, compared to control uncoated activated carbon, which yielded a cell recovery of only 1.1%±0.8%. In addition, the milk protein coated activated carbon was able to absorb similar amounts of soluble compounds as uncoated activated carbon, with the exception of bovine hemoglobin. This suggests that the use of milk proteins to coat activated carbon may therefore serve as a suitable replacement for bentonite in the coating of activated carbon, which has previously been used for the removal of PCR inhibitors from food.

  2. Loop-mediated isothermal amplification of specific endoglucanase gene sequence for detection of the bacterial wilt pathogen Ralstonia solanacearum.

    Directory of Open Access Journals (Sweden)

    Rok Lenarčič

    Full Text Available The increased globalization of crops production and processing industries also promotes the side-effects of more rapid and efficient spread of plant pathogens. To prevent the associated economic losses, and particularly those related to bacterial diseases where their management relies on removal of the infected material from production, simple, easy-to-perform, rapid and cost-effective tests are needed. Loop-mediated isothermal amplification (LAMP assays that target 16S rRNA, fliC and egl genes were compared and evaluated as on-site applications. The assay with the best performance was that targeted to the egl gene, which shows high analytical specificity for diverse strains of the betaproteobacterium Ralstonia solanacearum, including its non-European and non-race 3 biovar 2 strains. The additional melting curve analysis provides confirmation of the test results. According to our extensive assessment, the egl LAMP assay requires minimum sample preparation (a few minutes of boiling for the identification of pure cultures and ooze from symptomatic material, and it can also be used in a high-throughput format in the laboratory. This provides sensitive and reliable detection of R. solanacearum strains of different phylotypes.

  3. A simple and rapid method for extracting bacterial DNA from intestinal microflora for ERIC-PCR detection

    Institute of Scientific and Technical Information of China (English)

    Jin-Long Yang; Ming-Shu Wang; An-Chun Cheng; Kang-Cheng Pan; Chuan-Feng Li; Shu-Xuan Deng

    2008-01-01

    AIM: To develop a simple and convenient method for extracting genomic DNA from intestinal microflora for enterobacterial repetitive intergenic consensus (ERIC)-PCR detection.METHODS: Five methods of extracting bacterial DNA,including Tris-EDTA buffer, chelex-100, ultrapure water,2% sodium dodecyl sulfate and 10% Triton-100 with and without sonication, were compared with the commercial fecal DNA extraction kit method, which is considered as the gold standard for DNA extraction. The comparison was based on the yield and purity of DNA and the indexes of the structure and property of micro-organisms that were reflected by ERIC-PCR.RESULTS: The yield and purity of DNA obtained by the chelex method was similar to that obtained with the fecal DNA kit. The ERIC-PCR results obtained for the DNA extracted by the chelex method and those obtained for DNA extracted with the fecal DNA kit were basically the same.CONCLUSION: The chelex method is recommended for ERIC-PCR experiments in view of its simplicity and costeffectiveness; and it is suitable for extracting total DNA from intestinal micro-organisms, particularly for handling a large number of samples.

  4. Use of PCR-DHPLC with fluorescence detection for the characterization of the bacterial diversity during cassava (Manihot esculenta Crantz) fermentation.

    Science.gov (United States)

    Kodama, C S; Cuadros-Orellana, S; Bandeira, C H M M; Graças, D A; Santos, A S; Silva, A

    2014-02-28

    Denaturing high-performance liquid chromatography (DHPLC) has been described as a suitable method to study DNA polymorphisms. Here, cassava (Manihot esculenta Crantz) fermentation liquor was examined using DHPLC analysis to characterize the bacterial diversity during the fermentation process. GC-clamped amplicons corresponding to a variable region of the bacterial community 16S rDNA were synthesized using polymerase chain reaction (PCR) and then resolved on a base-composition basis using preparative DHPLC. Eluate fractions were collected at random and used as a source of whole community DNA that could be used to determine the bacterial diversity. As a first approach, GC-clamps were removed from the eluted DNA fragments using PCR to avoid the possible bias these clamps could cause during the construction of clone libraries. As a second approach, a clone library of each eluate sample was constructed, preserving the GC-clamps of the DNA fragments. The first approach generated 132 bacterial rDNA sequences with an average size of 200 bp, 45% of which had similarity to unculturable or non-classified bacteria. The second approach produced 194 sequences identified as Proteobacteria (48%), uncultured or non-classified environmental bacteria (40%) and Firmicutes (12%). We detected a remarkably greater bacterial diversity using the first approach than the second approach. The DHPLC-PCR method allowed for the fast and non-laborious detection of a vast bacterial diversity that was associated with cassava fermentation, and we conclude that it is a promising alternative for the characterization of the overall microbial diversity in complex samples.

  5. Infection of Bacterial Endosymbionts in Insects: A Comparative Study of Two Techniques viz PCR and FISH for Detection and Localization of Symbionts in Whitefly, Bemisia tabaci.

    Directory of Open Access Journals (Sweden)

    Harpreet Singh Raina

    Full Text Available Bacterial endosymbionts have been associated with arthropods and large number of the insect species show interaction with such bacteria. Different approaches have been used to understand such symbiont- host interactions. The whitefly, Bemisia tabaci, a highly invasive agricultural pest, harbors as many as seven different bacterial endosymbionts. These bacterial endosymbionts are known to provide various nutritional, physiological, environmental and evolutionary benefits to its insect host. In this study, we have tried to compare two techniques, Polymerase chain reaction (PCR and Flourescence in situ Hybridisation (FISH commonly used for identification and localization of bacterial endosymbionts in B. tabaci as it harbors one of the highest numbers of endosymbionts which have helped it in becoming a successful global invasive agricultural pest. The amplified PCR products were observed as bands on agarose gel by electrophoresis while the FISH samples were mounted on slides and observed under confocal microscope. Analysis of results obtained by these two techniques revealed the advantages of FISH over PCR. On a short note, performing FISH, using LNA probes proved to be more sensitive and informative for identification as well as localization of bacterial endosymbionts in B. tabaci than relying on PCR. This study would help in designing more efficient experiments based on much reliable detection procedure and studying the role of endosymbionts in insects.

  6. A multi-channel bioluminescent bacterial biosensor for the on-line detection of metals and toxicity. Part I: design and optimization of bioluminescent bacterial strains

    Energy Technology Data Exchange (ETDEWEB)

    Charrier, Thomas; Durand, Marie-Jose; Jouanneau, Sulivan; Thouand, Gerald [UMR CNRS 6144 GEPEA, CBAC, Nantes University, PRES UNAM, Campus de la Courtaisiere-IUT, La Roche-sur-Yon cedex (France); Dion, Michel [UMR CNRS 6204, Nantes University, PRES UNAM, Biotechnologie, Biocatalyse, Bioregulation, 2, Rue de la Houssiniere, BP 92208, Nantes cedex 3 (France); Pernetti, Mimma; Poncelet, Denis [ONIRIS-ENITIAA, UMR CNRS GEPEA, Rue de la Geraudiere, BP 82225, Nantes cedex 3 (France)

    2011-05-15

    This study describes the construction of inducible bioluminescent strains via genetic engineering along with their characterization and optimization in the detection of heavy metals. Firstly, a preliminary comparative study enabled us to select a suitable carbon substrate from pyruvate, glucose, citrate, diluted Luria-Bertani, and acetate. The latter carbon source provided the best induction ratios for comparison. Results showed that the three constructed inducible strains, Escherichia coli DH1 pBzntlux, pBarslux, and pBcoplux, were usable when conducting a bioassay after a 14-h overnight culture at 30 C. Utilizing these sensors gave a range of 12 detected heavy metals including several cross-detections. Detection limits for each metal were often close to and sometimes lower than the European standards for water pollution. Finally, in order to maintain sensitive bacteria within the future biosensor-measuring cell, the agarose immobilization matrix was compared to polyvinyl alcohol (PVA). Agarose was selected because the detection limits of the bioluminescent strains were not affected, in contrast to PVA. Specific detection and cross-detection ranges determined in this study will form the basis of a multiple metals detection system by the new multi-channel Lumisens3 biosensor. (orig.)

  7. Detection of respiratory viral and bacterial pathogens causing pediatric community-acquired pneumonia in Beijing using real-time PCR

    Institute of Scientific and Technical Information of China (English)

    Tie-Gang Zhang; Ai-Hua Li; Min Lyu; Meng Chen; Fang Huang; Jiang Wu

    2015-01-01

    Objective: The aim of this study was to determine the etiology and prevalence of pediatric CAP in Beijing using a real-time polymerase chain reaction (PCR) technique. Methods: Between February 15, 2011 and January 18, 2012, 371 pediatric patients with CAP were enrolled at Beijing Children's Hospital. Sixteen respiratory viruses and two bacteria were detected from tracheal aspirate specimens using commercially available multiplex real-time reverse transcription PCR (RT-PCR) kits. Results: A single viral pathogen was detected in 35.3%of enrolled patients, multiple viruses in 11.6%, and virus/bacteria co-infection in 17.8%. In contrast, only 6.5%of patients had a single bacterial pathogen and 2.2%were infected with multiple bacteria. The etiological agent was unknown for 26.7% of patients. The most common viruses were respiratory syncytial virus (RSV) (43.9%), rhinovirus (14.8%), parainfluenza virus (9.4%), and adenovirus (8.6%). In patients under three years of age, RSV (44.6%), rhinovirus (12.8%), and Streptococcus pneumoniae (9.9%) were the most frequent pathogens. In children aged 3e7 years, S. pneumoniae (38.9%), RSV (30.6%), Haemophilus influenzae (19.4%), and adenovirus (19.4%) were most prevalent. Finally in children over seven years, RSV (47.3%), S. pneumoniae (41.9%), and rhinovirus (21.5%) infections were most frequent. Conclusions: Viral pathogens, specifically RSV, were responsible for the majority of CAP in pediatric patients. However, both S. pneumoniae and H. influenzae contributed as major causes of disease. Commercially available multiplexing real-time PCR allowed for rapid detection of the etiological agent. Copyright © 2015, Chinese Medical Association Production. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  8. Application of quartz tuning forks for detection of endotoxins and Gram-negative bacterial cells by monitoring of Limulus Amebocyte Lysate coagulation.

    Science.gov (United States)

    Chałupniak, Andrzej; Waszczuk, Karol; Hałubek-Głuchowska, Katarzyna; Piasecki, Tomasz; Gotszalk, Teodor; Rybka, Jacek

    2014-08-15

    Endotoxins, pyrogens of bacterial origin, are a significant threat in many areas of life. Currently, the test most commonly used for endotoxin level determination is LAL (Limulus Amebocyte Lysate) assay. This paper presents application of commercially available low-frequency piezoelectric tuning forks (QTFs) for endotoxin detection. Measurement of the decrease in the QTF oscillation amplitude provides information about the viscosity changes, occurring in the tested sample upon addition of LAL. That method was used to determine the concentrations of endotoxins and bacterial cells (E. coli O157:H19). The relevance of the obtained results was confirmed using a commercially available colorimetric LAL assay. The constructed system can detect bacterial endotoxins in the range of 0.001-5EU/ml and bacterial cells in the range of 10(2)-10(7)CFU/ml. The presented technique requires very simple sample preparation and the sensor response is obtained using compact, portable readout electronics. The single test cost is low compared to commercial endotoxin assays and other novel systems based on micromechanical sensors. PMID:24632139

  9. Molecular detection of Candidatus Scalindua pacifica and environmental responses of sediment anammox bacterial community in the Bohai Sea, China.

    Directory of Open Access Journals (Sweden)

    Hongyue Dang

    Full Text Available The Bohai Sea is a large semi-enclosed shallow water basin, which receives extensive river discharges of various terrestrial and anthropogenic materials such as sediments, nutrients and contaminants. How these terrigenous inputs may influence the diversity, community structure, biogeographical distribution, abundance and ecophysiology of the sediment anaerobic ammonium oxidation (anammox bacteria was unknown. To answer this question, an investigation employing both 16S rRNA and hzo gene biomarkers was carried out. Ca. Scalindua bacteria were predominant in the surface sediments of the Bohai Sea, while non-Scalindua anammox bacteria were also detected in the Yellow River estuary and inner part of Liaodong Bay that received strong riverine and anthropogenic impacts. A novel 16S rRNA gene sequence clade was identified, putatively representing an anammox bacterial new candidate species tentatively named "Ca. Scalindua pacifica". Several groups of environmental factors, usually with distinct physicochemical or biogeochemical natures, including general marine and estuarine physicochemical properties, availability of anammox substrates (inorganic N compounds, alternative reductants and oxidants, environmental variations caused by river discharges and associated contaminants such as heavy metals, were identified to likely play important roles in influencing the ecology and biogeochemical functioning of the sediment anammox bacteria. In addition to inorganic N compounds that might play a key role in shaping the anammox microbiota, organic carbon, organic nitrogen, sulfate, sulfide and metals all showed the potentials to participate in the anammox process, releasing the strict dependence of the anammox bacteria upon the direct availability of inorganic N nutrients that might be limiting in certain areas of the Bohai Sea. The importance of inorganic N nutrients and certain other environmental factors to the sediment anammox microbiota suggests that these

  10. Optimization and evaluation of Flexicult(®) Vet for detection, identification and antimicrobial susceptibility testing of bacterial uropathogens in small animal veterinary practice

    DEFF Research Database (Denmark)

    Guardabassi, Luca; Hedberg, Sandra; Jessen, Lisbeth Rem;

    2015-01-01

    BACKGROUND: Urinary tract infection (UTI) is a common reason for antimicrobial prescription in dogs and cats. The objective of this study was to optimize and evaluate a culture-based point-of-care test for detection, identification and antimicrobial susceptibility testing of bacterial uro......-pathogens in veterinary practice. METHODS: Seventy-two urine samples from dogs and cats with suspected UTI presenting to seven veterinary facilities were used by clinical staff and an investigator to estimate sensitivity and specificity of Flexicult Vet A compared to laboratory reference standards for culture...... isolates. RESULTS: Bacteriuria was reported by the laboratory in 25 (35 %) samples from the field study. The sensitivity and specificity of Flexicult Vet A for detection of bacteriuria were 83 and 100 %, respectively. Bacterial species were correctly identified in 53 and 100 % of the positive samples...

  11. Nanomaterial-based sensors for detection of foodborne bacterial pathogens and toxins as well as pork adulteration in meat products

    OpenAIRE

    Stephen Inbaraj, B; Chen, B H

    2016-01-01

    Food safety draws considerable attention in the modern pace of the world owing to rapid-changing food recipes and food habits. Foodborne illnesses associated with pathogens, toxins, and other contaminants pose serious threat to human health. Besides, a large amount of money is spent on both analyses and control measures, which causes significant loss to the food industry. Conventional detection methods for bacterial pathogens and toxins are time consuming and laborious, requiring certain soph...

  12. Optimization and evaluation of Flexicult® Vet for detection, identification and antimicrobial susceptibility testing of bacterial uropathogens in small animal veterinary practice

    OpenAIRE

    Guardabassi, Luca; Hedberg, Sandra; Jessen, Lisbeth Rem; Damborg, Peter Panduro

    2015-01-01

    BACKGROUND: Urinary tract infection (UTI) is a common reason for antimicrobial prescription in dogs and cats. The objective of this study was to optimize and evaluate a culture-based point-of-care test for detection, identification and antimicrobial susceptibility testing of bacterial uro-pathogens in veterinary practice.METHODS: Seventy-two urine samples from dogs and cats with suspected UTI presenting to seven veterinary facilities were used by clinical staff and an investigator to estimate...

  13. Development of Real-Time PCR Methods for the Detection of Bacterial Meningitis Pathogens without DNA Extraction.

    Directory of Open Access Journals (Sweden)

    Jeni Vuong

    Full Text Available Neisseria meningitidis (Nm, Haemophilus influenzae (Hi, and Streptococcus pneumoniae (Sp are the lead causes of bacterial meningitis. Detection of these pathogens from clinical specimens using traditional real-time PCR (rt-PCR requires DNA extraction to remove the PCR inhibitors prior to testing, which is time consuming and labor intensive. In this study, five species-specific (Nm-sodC and -ctrA, Hi-hpd#1 and -hpd#3 and Sp-lytA and six serogroup-specific rt-PCR tests (A, B, C, W, X, Y targeting Nm capsular genes were evaluated in the two direct rt-PCR methods using PerfeCTa and 5x Omni that do not require DNA extraction. The sensitivity and specify of the two direct rt-PCR methods were compared to TaqMan traditional rt-PCR, the current standard rt-PCR method for the detection of meningitis pathogens. The LLD for all 11 rt-PCR tests ranged from 6,227 to 272,229 CFU/ml for TaqMan, 1,824-135,982 for 5x Omni, and 168-6,836 CFU/ml for PerfeCTa. The diagnostic sensitivity using TaqMan ranged from 89.2%-99.6%, except for NmB-csb, which was 69.7%. For 5x Omni, the sensitivity varied from 67.1% to 99.8%, with three tests below 90%. The sensitivity of these tests using PerfeCTa varied from 89.4% to 99.8%. The specificity ranges of the 11 tests were 98.0-99.9%, 97.5-99.9%, and 92.9-99.9% for TaqMan, 5x Omni, and PerfeCTa, respectively. PerfeCTa direct rt-PCR demonstrated similar or better sensitivity compared to 5x Omni direct rt-PCR or TaqMan traditional rt-PCR. Since the direct rt-PCR method does not require DNA extraction, it reduces the time and cost for processing CSF specimens, increases testing throughput, decreases the risk of cross-contamination, and conserves precious CSF. The direct rt-PCR method will be beneficial to laboratories with high testing volume.

  14. Detection of denitrification genes by in situ rolling circle amplification - fluorescence in situ hybridization (in situ RCA-FISH) to link metabolic potential with identity inside bacterial cells

    DEFF Research Database (Denmark)

    Hoshino, Tatsuhiko; Schramm, Andreas

    2010-01-01

    A target-primed in situ rolling circle amplification (in situ RCA) protocol was developed for detection of single-copy genes inside bacterial cells and optimized with Pseudomonas stutzeri, targeting nitrite and nitrous oxide reductase genes (nirS and nosZ). Two padlock probes were designed per gene...... as Candidatus Accumulibacter phosphatis by combining in situ RCA-FISH with 16S rRNA-targeted FISH. While not suitable for quantification because of its low detection frequency, in situ RCA-FISH will allow to link metabolic potential with 16S rRNA (gene)-based identification of single microbial cells....

  15. Survey of childhood empyema in Asia: Implications for detecting the unmeasured burden of culture-negative bacterial disease

    Directory of Open Access Journals (Sweden)

    Shen Xuzhuang

    2008-07-01

    Full Text Available Abstract Background Parapneumonic empyema continues to be a disease of significant morbidity and mortality among children despite recent advances in medical management. To date, only a limited number of studies have assessed the burden of empyema in Asia. Methods We surveyed medical records of four representative large pediatric hospitals in China, Korea, Taiwan and Vietnam using ICD-10 diagnostic codes to identify children Results During the study period, we identified 1,379 children diagnosed with empyema or pleural effusion (China, n = 461; Korea, n = 134; Taiwan, n = 119; Vietnam, n = 665. Diagnoses of pleural effusion (n = 1,074 were 3.5 times more common than of empyema (n = 305, although the relative proportions of empyema and pleural effusion noted in hospital records varied widely between the four sites, most likely because of marked differences in coding practices. Although pleural effusions were reported more often than empyema, children with empyema were more likely to have a cultured pathogen. In addition, we found that median age and gender distribution of children with these conditions were similar across the four countries. Among 1,379 empyema and pleural effusion specimens, 401 (29% were culture positive. Staphylococcus aureus (n = 126 was the most common organism isolated, followed by Streptococcus pneumoniae (n = 83, Pseudomonas aeruginosa (n = 37 and Klebsiella (n = 35 and Acinetobacter species (n = 34. Conclusion The age and gender distribution of empyema and pleural effusion in children in these countries are similar to the US and Western Europe. S. pneumoniae was the second leading bacterial cause of empyema and pleural effusion among Asian children. The high proportion of culture-negative specimens among patients with pleural effusion or empyema suggests that culture may not be a sufficiently sensitive diagnostic method to determine etiology in the majority of cases. Future prospective studies in different countries would

  16. Nanomaterial-based sensors for detection of foodborne bacterial pathogens and toxins as well as pork adulteration in meat products

    Directory of Open Access Journals (Sweden)

    B. Stephen Inbaraj

    2016-01-01

    Full Text Available Food safety draws considerable attention in the modern pace of the world owing to rapid-changing food recipes and food habits. Foodborne illnesses associated with pathogens, toxins, and other contaminants pose serious threat to human health. Besides, a large amount of money is spent on both analyses and control measures, which causes significant loss to the food industry. Conventional detection methods for bacterial pathogens and toxins are time consuming and laborious, requiring certain sophisticated instruments and trained personnel. In recent years, nanotechnology has emerged as a promising field for solving food safety issues in terms of detecting contaminants, enabling controlled release of preservatives to extend the shelf life of foods, and improving food-packaging strategies. Nanomaterials including metal oxide and metal nanoparticles, carbon nanotubes, and quantum dots are gaining a prominent role in the design of sensors and biosensors for food analysis. In this review, various nanomaterial-based sensors reported in the literature for detection of several foodborne bacterial pathogens and toxins are summarized highlighting their principles, advantages, and limitations in terms of simplicity, sensitivity, and multiplexing capability. In addition, the application through a noncross-linking method without the need for any surface modification is also presented for detection of pork adulteration in meat products.

  17. The potential of spectral and hyperspectral-imaging techniques for bacterial detection in food: A case study on lactic acid bacteria.

    Science.gov (United States)

    Foca, Giorgia; Ferrari, Carlotta; Ulrici, Alessandro; Sciutto, Giorgia; Prati, Silvia; Morandi, Stefano; Brasca, Milena; Lavermicocca, Paola; Lanteri, Silvia; Oliveri, Paolo

    2016-06-01

    Official methods for the detection of bacteria are based on culture techniques. These methods have limitations such as time consumption, cost, detection limits and the impossibility to analyse a large number of samples. For these reasons, the development of rapid, low-cost and non-destructive analytical methods is a task of growing interest. In the present study, the capability of spectral and hyperspectral techniques to detect bacterial surface contamination was investigated preliminarily on gel cultures, and subsequently on sliced cooked ham. In more detail, two species of lactic acid bacteria (LAB) were considered, namely Lactobacillus curvatus and Lactobacillus sakei, both of which are responsible for common alterations in sliced cooked ham. Three techniques were investigated, with different equipment, respectively: a macroscopic hyperspectral scanner operating in the NIR (10,470-5880cm(-1)) region, a FT-NIR spectrophotometer equipped with a transmission arm as the sampling tool, working in the 12,500-5800cm(-1) region, and a FT-MIR microscopy operating in the 4000-675cm(-1) region. Multivariate exploratory data analysis, in particular principal component analysis (PCA), was applied in order to extract useful information from original data and from hyperspectrograms. The results obtained demonstrate that the spectroscopic and imaging techniques investigated can represent an effective and sensitive tool to detect surface bacterial contamination in samples and, in particular, to recognise species to which bacteria belong.

  18. DETECTION OF BACTERIAL CYTOTOXIC ACTIVITIES FROM WATER-DAMAGED CEILING TILE MATERIAL FOLLOWING INCUBATION ON BLOOD AGAR

    Science.gov (United States)

    Samples of ceiling tiles with high levels of bacteria exhibited cytotoxic activities on a HEP-2 tissue culture assay. Ceiling tiles containing low levels of bacterial colonization did not show cytotoxic activities on the HEP-2 tissue culture assay. Using a spread plate procedure ...

  19. PCR-Independent Detection of Bacterial Species-Specific 16S rRNA at 10 fM by a Pore-Blockage Sensor

    Science.gov (United States)

    Esfandiari, Leyla; Wang, Siqing; Wang, Siqi; Banda, Anisha; Lorenzini, Michael; Kocharyan, Gayane; Monbouquette, Harold G.; Schmidt, Jacob J.

    2016-01-01

    A PCR-free, optics-free device is used for the detection of Escherichia coli (E. coli) 16S rRNA at 10 fM, which corresponds to ~100–1000 colony forming units/mL (CFU/mL) depending on cellular rRNA levels. The development of a rapid, sensitive, and cost-effective nucleic acid detection platform is sought for the detection of pathogenic microbes in food, water and body fluids. Since 16S rRNA sequences are species specific and are present at high copy number in viable cells, these nucleic acids offer an attractive target for microbial pathogen detection schemes. Here, target 16S rRNA of E. coli at 10 fM concentration was detected against a total RNA background using a conceptually simple approach based on electromechanical signal transduction, whereby a step change reduction in ionic current through a pore indicates blockage by an electrophoretically mobilized bead-peptide nucleic acid probe conjugate hybridized to target nucleic acid. We investigated the concentration detection limit for bacterial species-specific 16S rRNA at 1 pM to 1 fM and found a limit of detection of 10 fM for our device, which is consistent with our previous finding with single-stranded DNA of similar length. In addition, no false positive responses were obtained with control RNA and no false negatives with target 16S rRNA present down to the limit of detection (LOD) of 10 fM. Thus, this detection scheme shows promise for integration into portable, low-cost systems for rapid detection of pathogenic microbes in food, water and body fluids. PMID:27455337

  20. Molecular analysis of bacterial communities and detection of potential pathogens in a recirculating aquaculture system for Scophthalmus maximus and Solea senegalensis.

    Directory of Open Access Journals (Sweden)

    Patrícia Martins

    Full Text Available The present study combined a DGGE and barcoded 16S rRNA pyrosequencing approach to assess bacterial composition in the water of a recirculating aquaculture system (RAS with a shallow raceway system (SRS for turbot (Scophthalmus maximus and sole (Solea senegalensis. Barcoded pyrosequencing results were also used to determine the potential pathogen load in the RAS studied. Samples were collected from the water supply pipeline (Sup, fish production tanks (Pro, sedimentation filter (Sed, biofilter tank (Bio, and protein skimmer (Ozo; also used as an ozone reaction chamber of twin RAS operating in parallel (one for each fish species. Our results revealed pronounced differences in bacterial community composition between turbot and sole RAS, suggesting that in the systems studied there is a strong species-specific effect on water bacterial communities. Proteobacteria was the most abundant phylum in the water supply and all RAS compartments. Other important taxonomic groups included the phylum Bacteriodetes. The saltwater supplied displayed a markedly lower richness and appeared to have very little influence on bacterial composition. The following potentially pathogenic species were detected: Photobacterium damselae in turbot (all compartments, Tenacibaculum discolor in turbot and sole (all compartments, Tenacibaculum soleae in turbot (all compartments and sole (Pro, Sed and Bio, and Serratia marcescens in turbot (Sup, Sed, Bio and Ozo and sole (only Sed RAS. Despite the presence of these pathogens, no symptomatic fish were observed. Although we were able to identify potential pathogens, this approach should be employed with caution when monitoring aquaculture systems, as the required phylogenetic resolution for reliable identification of pathogens may not always be possible to achieve when employing 16S rRNA gene fragments.

  1. Molecular analysis of bacterial communities and detection of potential pathogens in a recirculating aquaculture system for Scophthalmus maximus and Solea senegalensis.

    Science.gov (United States)

    Martins, Patrícia; Cleary, Daniel F R; Pires, Ana C C; Rodrigues, Ana Maria; Quintino, Victor; Calado, Ricardo; Gomes, Newton C M

    2013-01-01

    The present study combined a DGGE and barcoded 16S rRNA pyrosequencing approach to assess bacterial composition in the water of a recirculating aquaculture system (RAS) with a shallow raceway system (SRS) for turbot (Scophthalmus maximus) and sole (Solea senegalensis). Barcoded pyrosequencing results were also used to determine the potential pathogen load in the RAS studied. Samples were collected from the water supply pipeline (Sup), fish production tanks (Pro), sedimentation filter (Sed), biofilter tank (Bio), and protein skimmer (Ozo; also used as an ozone reaction chamber) of twin RAS operating in parallel (one for each fish species). Our results revealed pronounced differences in bacterial community composition between turbot and sole RAS, suggesting that in the systems studied there is a strong species-specific effect on water bacterial communities. Proteobacteria was the most abundant phylum in the water supply and all RAS compartments. Other important taxonomic groups included the phylum Bacteriodetes. The saltwater supplied displayed a markedly lower richness and appeared to have very little influence on bacterial composition. The following potentially pathogenic species were detected: Photobacterium damselae in turbot (all compartments), Tenacibaculum discolor in turbot and sole (all compartments), Tenacibaculum soleae in turbot (all compartments) and sole (Pro, Sed and Bio), and Serratia marcescens in turbot (Sup, Sed, Bio and Ozo) and sole (only Sed) RAS. Despite the presence of these pathogens, no symptomatic fish were observed. Although we were able to identify potential pathogens, this approach should be employed with caution when monitoring aquaculture systems, as the required phylogenetic resolution for reliable identification of pathogens may not always be possible to achieve when employing 16S rRNA gene fragments. PMID:24278329

  2. Modulation of population density and size of silver nanoparticles embedded in bacterial cellulose via ammonia exposure: visual detection of volatile compounds in a piece of plasmonic nanopaper

    Science.gov (United States)

    Heli, B.; Morales-Narváez, E.; Golmohammadi, H.; Ajji, A.; Merkoçi, A.

    2016-04-01

    The localized surface plasmon resonance exhibited by noble metal nanoparticles can be sensitively tuned by varying their size and interparticle distances. We report that corrosive vapour (ammonia) exposure dramatically reduces the population density of silver nanoparticles (AgNPs) embedded within bacterial cellulose, leading to a larger distance between the remaining nanoparticles and a decrease in the UV-Vis absorbance associated with the AgNP plasmonic properties. We also found that the size distribution of AgNPs embedded in bacterial cellulose undergoes a reduction in the presence of volatile compounds released during food spoilage, modulating the studied nanoplasmonic properties. In fact, such a plasmonic nanopaper exhibits a change in colour from amber to light amber upon the explored corrosive vapour exposure and from amber to a grey or taupe colour upon fish or meat spoilage exposure. These phenomena are proposed as a simple visual detection of volatile compounds in a flexible, transparent, permeable and stable single-use nanoplasmonic membrane, which opens the way to innovative approaches and capabilities in gas sensing and smart packaging.The localized surface plasmon resonance exhibited by noble metal nanoparticles can be sensitively tuned by varying their size and interparticle distances. We report that corrosive vapour (ammonia) exposure dramatically reduces the population density of silver nanoparticles (AgNPs) embedded within bacterial cellulose, leading to a larger distance between the remaining nanoparticles and a decrease in the UV-Vis absorbance associated with the AgNP plasmonic properties. We also found that the size distribution of AgNPs embedded in bacterial cellulose undergoes a reduction in the presence of volatile compounds released during food spoilage, modulating the studied nanoplasmonic properties. In fact, such a plasmonic nanopaper exhibits a change in colour from amber to light amber upon the explored corrosive vapour exposure and

  3. Highly selective detection of bacterial alarmone ppGpp with an off-on fluorescent probe of copper-mediated silver nanoclusters.

    Science.gov (United States)

    Zhang, Pu; Wang, Yi; Chang, Yong; Xiong, Zu Hong; Huang, Cheng Zhi

    2013-11-15

    In this study, a facile strategy for highly selective and sensitive detection of bacterial alarmone, ppGpp, which is generated when bacteria face stress circumstances such as nutritional deprivation, has been established by developing an off-on fluorescent probe of Cu(2+)-mediated silver nanoclusters (Ag NCs). This work not only achieves highly selective detection of ppGpp in a broad range concentration of 2-200 μM, but also improves our understanding of the specific recognitions among DNA-Ag NCs, Cu(2+), and ppGpp. The present strategy, together with other reports on the Ag NCs-related analytical methods, has also identified that Ag NCs functionalized with different molecules on their surfaces can be engineered fluorescent probes for a wide range of applications such as biosensing and bioimaging.

  4. Identification of a novel calcium binding motif based on the detection of sequence insertions in the animal peroxidase domain of bacterial proteins.

    Directory of Open Access Journals (Sweden)

    Saray Santamaría-Hernando

    Full Text Available Proteins of the animal heme peroxidase (ANP superfamily differ greatly in size since they have either one or two catalytic domains that match profile PS50292. The orf PP_2561 of Pseudomonas putida KT2440 that we have called PepA encodes a two-domain ANP. The alignment of these domains with those of PepA homologues revealed a variable number of insertions with the consensus G-x-D-G-x-x-[GN]-[TN]-x-D-D. This motif has also been detected in the structure of pseudopilin (pdb 3G20, where it was found to be involved in Ca(2+ coordination although a sequence analysis did not reveal the presence of any known calcium binding motifs in this protein. Isothermal titration calorimetry revealed that a peptide containing this consensus motif bound specifically calcium ions with affinities ranging between 33-79 µM depending on the pH. Microcalorimetric titrations of the purified N-terminal ANP-like domain of PepA revealed Ca(2+ binding with a K(D of 12 µM and stoichiometry of 1.25 calcium ions per protein monomer. This domain exhibited peroxidase activity after its reconstitution with heme. These data led to the definition of a novel calcium binding motif that we have termed PERCAL and which was abundantly present in animal peroxidase-like domains of bacterial proteins. Bacterial heme peroxidases thus possess two different types of calcium binding motifs, namely PERCAL and the related hemolysin type calcium binding motif, with the latter being located outside the catalytic domains and in their C-terminal end. A phylogenetic tree of ANP-like catalytic domains of bacterial proteins with PERCAL motifs, including single domain peroxidases, was divided into two major clusters, representing domains with and without PERCAL motif containing insertions. We have verified that the recently reported classification of bacterial heme peroxidases in two families (cd09819 and cd09821 is unrelated to these insertions. Sequences matching PERCAL were detected in all kingdoms of

  5. Screening the thermophilic and hyperthermophilic bacterial population of three Iranian hot-springs to detect the thermostable α- amylase producing strain

    Directory of Open Access Journals (Sweden)

    A Sajjadian

    2010-06-01

    Full Text Available Background: Screening is a routine procedure for isolation of microorganisms which are able to produce special metabolites. Purified thermostable α-amylase from bacterial sources is widely used in different industries. In this study we analyzed samples collected from three different hot springs in Iran to detect any strains capable of producing thermostable α-amylase."nMaterials and Methods: Hot water samples from Larijan (67°C, pH 6.5, Mahallat (46°C, pH 7, and Meshkinshahr (82°C, pH 6, were cultivated in screening starch agar plates and incubated at 65°C for 24 hours. Thereafter, the plates were stained with Gram's iodine solution."nResults and Discussion: The bacterial colonies from the Meshkinshahr hot-spring produced the largest haloforming zone. Based on the phenotypic tests, the strain was identified as Bacillus sp. The culture condition was optimized for biosynthesis of α-amylase. The enzyme was produced at maximum level when it was incubated at 70 °C in the presence of soluble starch (1% at pH 6. The addition of calcium (10 mM and peptone (1% to the mineral medium, shortened the lag period and improved the growth and α-amylase synthesis. The addition of glucose (1% to the culture greatly diminished the syntheses of α -amylase. Importantly, the enzyme extract retained 100% activity when incubated for 45 minutes at 100°C."nConclusion: The Meshkinshahr hot-spring is rich in the Bacillus spp thermostable α-amylase producing strain of the thermophilic bacterial population. Iranian hot-springs like Meshkinshahr, have large microbial storages and can be used as sources of different biological products like enzymes. The enzyme which was produced with Bacillus sp. could hydrolyse polymers like starch and was used at laboratory scale successfully.

  6. Rapid detection and identification of viral and bacterial fish pathogens using a DNA array‐based multiplex assay

    DEFF Research Database (Denmark)

    Lievens, B.; Frans, I.; Heusdens, C.;

    2011-01-01

    Fish diseases can be caused by a variety of diverse organisms, including bacteria, fungi, viruses and protozoa, and pose a universal threat to the ornamental fish industry and aquaculture. The lack of rapid, accurate and reliable means by which fish pathogens can be detected and identified has been...... for sensitive pathogen detection and identification in complex samples such as infected tissue is demonstrated in this study....

  7. Analysis of BDS/GPS Integrated Navigation System in Asia-Pacific Region%BDS和GPS导航系统亚太地区定位性能分析

    Institute of Scientific and Technical Information of China (English)

    雷俊科

    2015-01-01

    通过仿真在轨的北斗卫星和GPS卫星,利用STK覆盖功能分析北斗、GPS和北斗/GPS组合导航系统在亚太地区的定位性能,并比较北斗/GPS组合卫星导航系统与单系统相比的优势。仿真结果表明北斗/GPS组合卫星导航系统在亚太地区有更好的可用性,能提供更高精度的导航定位服务。%The working BDS and GPS satellites are simulated in this paper. The performance of BDS,GPS and BDS/GPS integrated navigation system is analyzed by using STK coverage tools. The result shows that BDS/GPS integrated navigation system has a better availability and it can provide more precise poisoning service.

  8. Incorporation of a lambda phage recombination system and EGFP detection to simplify mutagenesis of Herpes simplex virus bacterial artificial chromosomes

    Directory of Open Access Journals (Sweden)

    Weir Jerry P

    2007-05-01

    Full Text Available Abstract Background Targeted mutagenesis of the herpesvirus genomes has been facilitated by the use of bacterial artificial chromosome (BAC technology. Such modified genomes have potential uses in understanding viral pathogenesis, gene identification and characterization, and the development of new viral vectors and vaccines. We have previously described the construction of a herpes simplex virus 2 (HSV-2 BAC and the use of an allele replacement strategy to construct HSV-2 recombinants. While the BAC mutagenesis procedure is a powerful method to generate HSV-2 recombinants, particularly in the absence of selective marker in eukaryotic culture, the mutagenesis procedure is still difficult and cumbersome. Results Here we describe the incorporation of a phage lambda recombination system into an allele replacement vector. This strategy enables any DNA fragment containing the phage attL recombination sites to be efficiently inserted into the attR sites of the allele replacement vector using phage lambda clonase. We also describe how the incorporation of EGFP into the allele replacement vector can facilitate the selection of the desired cross-over recombinant BACs when the allele replacement reaction is a viral gene deletion. Finally, we incorporate the lambda phage recombination sites directly into an HSV-2 BAC vector for direct recombination of gene cassettes using the phage lambda clonase-driven recombination reaction. Conclusion Together, these improvements to the techniques of HSV BAC mutagenesis will facilitate the construction of recombinant herpes simplex viruses and viral vectors.

  9. PCR amplfication on a microarray of gel-immobilized oligonucleotides : detection of bacterial toxin- and drug-resistent genes and their mutations.

    Energy Technology Data Exchange (ETDEWEB)

    Strizhkov, B. N.; Drobyshev, A. L.; Mikhailovich, V. M.; Mirzabekov, A. D.; Biochip Technology Center; Engelhardt Inst. of Molecular Biology

    2000-10-01

    PCR amplification on a microarray of gel-immobilized primers (microchip) has been developed. One of a pair of PCR primers was immobilized inside a separate microchip polyacrylamide porous gel pad of 0.1 x 0.1 x 0.02 (or 0.04) micron in size and 0.2 (or 0.4) nL in volume. The amplification was carried out simultaneously both in solution covering the microchip array and inside gel pads. Each gel pad contained the immobilized forward primers, while the fluorescently labeled reverse primers, as well as all components of the amplification reaction, diffused into the gel pads from the solution. To increase the amplification efficiency, the forward primers were also added into the solution. The kinetics of amplification was measured in real time in parallel for all gel pads with a fluorescent microscope equipped with a charge-coupled device (CCD) camera. The accuracy of the amplification was assessed by using the melting curves obtained for the duplexes formed by the labeled amplification product and the gel-immobilized primers during the amplification process; alternatively, the duplexes were produced by hybridization of the extended immobilized primers with labeled oligonucleotide probes. The on-chip amplification was applied to detect the anthrax toxin genes and the plasmid-borne beta-lactamase gene responsible for bacterial ampicillin resistance. The allele-specific type of PCR amplification was used to identify the Shiga toxin gene and discriminate it from the Shiga-like one. The genomic mutations responsible for rifampicin resistance of the Mycobacterium tuberculosis strains were detected by the same type of PCR amplification of the rpoB gene fragment isolated from sputum of tuberculosis patients. The on-chip PCR amplification has been shown to be a rapid, inexpensive and powerful tool to test genes responsible for bacterial toxin production and drug resistance, as well as to reveal point nucleotide mutations.

  10. Detection of Ca2+-dependent acid phosphatase activity identifies neuronal integrity in damaged rat central nervous system after application of bacterial melanin

    Directory of Open Access Journals (Sweden)

    Tigran R Petrosyan

    2016-01-01

    Full Text Available The study aims to confirm the neuroregenerative effects of bacterial melanin (BM on central nervous system injury using a special staining method based on the detection of Ca2+-dependent acid phosphatase activity. Twenty-four rats were randomly assigned to undergo either unilateral destruction of sensorimotor cortex (group I; n = 12 or unilateral rubrospinal tract transection at the cervical level (C3–4 (group II; n = 12. In each group, six rats were randomly selected after surgery to undergo intramuscular injection of BM solution (BM subgroup and the remaining six rats were intramuscularly injected with saline (saline subgroup. Neurological testing confirmed that BM accelerated the recovery of motor function in rats from both BM and saline subgroups. Two months after surgery, Ca2+-dependent acid phosphatase activity detection in combination with Chilingarian's calcium adenoside triphosphate method revealed that BM stimulated the sprouting of fibers and dilated the capillaries in the brain and spinal cord. These results suggest that BM can promote the recovery of motor function of rats with central nervous system injury; and detection of Ca2+-dependent acid phosphatase activity is a fast and easy method used to study the regeneration-promoting effects of BM on the injured central nervous system.

  11. Detection of Ca2+-dependent acid phosphatase activity identiifes neuronal integrity in damaged rat central nervous system after application of bacterial melanin

    Institute of Scientific and Technical Information of China (English)

    Tigran R Petrosyan; Anna S Ter-Markosyan; Anna S Hovsepyan

    2016-01-01

    The study aims to confirm the neuroregenerative effects of bacterial melanin (BM) on central nervous system injury using a special staining method based on the detection of Ca2+-dependent acid phosphatase activity. Twenty-four rats were randomly assigned to undergo either unilateral destruction of sensorimotor cortex (group I;n=12) or unilateral rubrospinal tract transection at the cervical level (C3–4) (group II;n=12). In each group, six rats were randomly selected after surgery to undergo intramuscular injection of BM solution (BM subgroup) and the remaining six rats were intramuscularly injected with saline (saline subgroup). Neurological testing confirmed that BM accelerated the recovery of motor function in rats from both BM and saline subgroups. Two months after surgery, Ca2+-dependent acid phosphatase activity detection in combination with Chilingarian’s calcium adenoside triphosphate method revealed that BM stimulated the sprouting of ifbers and dilated the capillaries in the brain and spinal cord. These results sug-gest that BM can promote the recovery of motor function of rats with central nervous system injury;and detection of Ca2+-dependent acid phosphatase activity is a fast and easy method used to study the regenera-tion-promoting effects of BM on the injured central nervous system.

  12. Investigation of the utility of complementary electrochemical detection techniques to examine the in vitro affinity of bacterial flagellins for a toll-like receptor 5 biosensor.

    Science.gov (United States)

    She, Zhe; Topping, Kristin; Shamsi, Mohtashim H; Wang, Nan; Chan, Nora W C; Kraatz, Heinz-Bernhard

    2015-04-21

    An initial investigation of the fabrication of a novel biosensor utilizing toll-like receptor 5 (TLR5) has been conducted. The detection assay using this sensor platform has been carried out using two complementary electrochemical techniques. The electrochemical properties of the modified bare gold surface following TLR5 immobilization were characterized. The electrochemical response to changes in the sensor film resistance and electron charge-transfer permittivity triggered by independent exposures to flagellins from Salmonella typhimurium (S. typhimurium) and Bacillus subtilis (B. subtilis) were examined and observed. The quantified film resistance data gathered using electrochemical impedance spectroscopy (EIS) over a macroscopic scale are in significant agreement with the corresponding electron charge-transfer permittivity measured locally by scanning electrochemical microscopy (SECM). Unlike other sensors that exploit pathogen recognition elements, TLR5 biosensors have the potential to carry out broad-spectrum detection of flagellated bacterial pathogens in near real time. This broad-spectrum detection platform is a significant step toward the development of fast, inexpensive clinical tools for early warning diagnoses and immediate on-site treatment.

  13. Detection of Ca(2+)-dependent acid phosphatase activity identifies neuronal integrity in damaged rat central nervous system after application of bacterial melanin.

    Science.gov (United States)

    Petrosyan, Tigran R; Ter-Markosyan, Anna S; Hovsepyan, Anna S

    2016-07-01

    The study aims to confirm the neuroregenerative effects of bacterial melanin (BM) on central nervous system injury using a special staining method based on the detection of Ca(2+)-dependent acid phosphatase activity. Twenty-four rats were randomly assigned to undergo either unilateral destruction of sensorimotor cortex (group I; n = 12) or unilateral rubrospinal tract transection at the cervical level (C3-4) (group II; n = 12). In each group, six rats were randomly selected after surgery to undergo intramuscular injection of BM solution (BM subgroup) and the remaining six rats were intramuscularly injected with saline (saline subgroup). Neurological testing confirmed that BM accelerated the recovery of motor function in rats from both BM and saline subgroups. Two months after surgery, Ca(2+)-dependent acid phosphatase activity detection in combination with Chilingarian's calcium adenoside triphosphate method revealed that BM stimulated the sprouting of fibers and dilated the capillaries in the brain and spinal cord. These results suggest that BM can promote the recovery of motor function of rats with central nervous system injury; and detection of Ca(2+)-dependent acid phosphatase activity is a fast and easy method used to study the regeneration-promoting effects of BM on the injured central nervous system. PMID:27630700

  14. Development of a visual loop-mediated isothermal amplification method for rapid detection of the bacterial pathogen Pseudomonas putida of the large yellow croaker (Pseudosciaena crocea).

    Science.gov (United States)

    Mao, Zhijuan; Qiu, Yangyu; Zheng, Lei; Chen, Jigang; Yang, Jifang

    2012-06-01

    In recent years, the large yellow croaker (Pseudosciaena crocea), an important marine fish farmed in the coastal areas of Zhejiang province, east China, has become severely endangered as a result of the bacterial pathogen Pseudomonas putida. This paper reports the development of a visual loop-mediated isothermal amplification (LAMP) assay for rapid detection of the pathogen. Four primers, F3, B3, FIP and BIP, were designed on the basis of DNA sequence of the rpoN gene of P. putida. After optimization of the reaction conditions, the detection limit of LAMP assay was 4.8cfu per reaction, 10-fold higher than that of conventional PCR. The assay showed high specificity to discriminate all P. putida isolates from nine other Gram-negative bacteria. The assay also successfully detected the pathogen DNA in the tissues of infected fish. For visual LAMP without cross-contamination, SYBR Green I was embedded in a microcrystalline wax capsule and preset in the reaction tubes; after the reaction the wax was melted at 85°C to release the dye and allow intercalation with the amplicons. The simple, highly sensitive, highly specific and cost-effective characteristics of visual LAMP may encourage its application in the rapid diagnosis of this pathogen.

  15. Graphene Oxide/Silver Nanohybrid as Multi-functional Material for Highly Efficient Bacterial Disinfection and Detection of Organic Dye

    Science.gov (United States)

    Tam, Le Thi; Dinh, Ngo Xuan; Van Cuong, Nguyen; Van Quy, Nguyen; Huy, Tran Quang; Ngo, Duc-The; Mølhave, Kristian; Le, Anh-Tuan

    2016-10-01

    In this work, a multi-functional hybrid system consisting of graphene oxide and silver nanoparticles (GO-Ag NPs) was successfully synthesized by using a two-step chemical process. We firstly demonstrated noticeable bactericidal ability of the GO-Ag hybrid system. We provide more chemo-physical evidence explaining the antibacterial behavior of GO-Ag nanohybrid against Gram-negative Escherichia Coli and Gram-positive Staphylococcus aureus in light of ultrastructural damage analyses and Ag1+ ions release rate onto the cells/medium. A further understanding of the mode of antimicrobial action is very important for designing and developing advanced antimicrobial systems. Secondly, we have also demonstrated that the GO-Ag nanohybrid material could be used as a potential surface enhanced Raman scattering (SERS) substrate to detect and quantify organic dyes, e.g., methylene blue (MB), in aqueous media. Our findings revealed that the GO-Ag hybrid system showed better SERS performance of MB detection than that of pure Ag-NPs. MB could be detected at a concentration as low as 1 ppm. The GO-Ag-based SERS platform can be effectively used to detect trace concentrations of various types of organic dyes in aqueous media. With the aforementioned properties, the GO-Ag hybrid system is found to be very promising as a multi-functional material for advanced biomedicine and environmental monitoring applications.

  16. Graphene Oxide/Silver Nanohybrid as Multi-functional Material for Highly Efficient Bacterial Disinfection and Detection of Organic Dye

    Science.gov (United States)

    Tam, Le Thi; Dinh, Ngo Xuan; Van Cuong, Nguyen; Van Quy, Nguyen; Huy, Tran Quang; Ngo, Duc-The; Mølhave, Kristian; Le, Anh-Tuan

    2016-06-01

    In this work, a multi-functional hybrid system consisting of graphene oxide and silver nanoparticles (GO-Ag NPs) was successfully synthesized by using a two-step chemical process. We firstly demonstrated noticeable bactericidal ability of the GO-Ag hybrid system. We provide more chemo-physical evidence explaining the antibacterial behavior of GO-Ag nanohybrid against Gram-negative Escherichia Coli and Gram-positive Staphylococcus aureus in light of ultrastructural damage analyses and Ag1+ ions release rate onto the cells/medium. A further understanding of the mode of antimicrobial action is very important for designing and developing advanced antimicrobial systems. Secondly, we have also demonstrated that the GO-Ag nanohybrid material could be used as a potential surface enhanced Raman scattering (SERS) substrate to detect and quantify organic dyes, e.g., methylene blue (MB), in aqueous media. Our findings revealed that the GO-Ag hybrid system showed better SERS performance of MB detection than that of pure Ag-NPs. MB could be detected at a concentration as low as 1 ppm. The GO-Ag-based SERS platform can be effectively used to detect trace concentrations of various types of organic dyes in aqueous media. With the aforementioned properties, the GO-Ag hybrid system is found to be very promising as a multi-functional material for advanced biomedicine and environmental monitoring applications.

  17. Comparison of the EntericBio multiplex PCR system with routine culture for detection of bacterial enteric pathogens.

    LENUS (Irish Health Repository)

    O'Leary, James

    2009-11-01

    The EntericBio system uses a multiplex PCR assay for the simultaneous detection of Campylobacter spp., Salmonella enterica, Shigella spp., and Escherichia coli O157 from feces. It combines overnight broth enrichment with PCR amplification and detection by hybridization. An evaluation of this system was conducted by comparing the results obtained with the system with those obtained by routine culture, supplemented with alternative PCR detection methods. In a study of 773 samples, routine culture and the EntericBio system yielded 94.6 and 92.4% negative results, respectively. Forty-two samples had positive results by culture, and all of these were positive with the EntericBio system. This system detected an additional 17 positive samples (Campylobacter spp., n = 12; Shigella spp., n = 1; E. coli O157, n = 4), but the results for 5 samples (Campylobacter spp., n = 2; Shigella spp., n = 1; E. coli O157, n = 2) could not be confirmed. The target for Shigella spp. detected by the EntericBio system is the ipaH gene, and the molecular indication of the presence of Shigella spp. was investigated by sequence analysis, which confirmed that the ipaH gene was present in a Klebsiella pneumoniae isolate from the patient. The sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 99.3%, 91.5%, and 100%, respectively. Turnaround times were significantly reduced with the EntericBio system, and a result was available between 24 and 32 h after receipt of the sample in the laboratory. In addition, the amount of laboratory waste was significantly reduced by use of this system. In summary, the EntericBio system proved convenient to use, more sensitive than the conventional culture used in this study, and highly specific; and it generated results significantly faster than routine culture for the pathogens tested.

  18. Atrazine biodegradation efficiency, metabolite detection, and trzD gene expression by enrichment bacterial cultures from agricultural soil

    Institute of Scientific and Technical Information of China (English)

    Robinson David Jebakumar SOLOMON; Amit KUMAR; Velayudhan SATHEEJA SANTHI

    2013-01-01

    Atrazine is a selective herbicide used in agricultural fields to control the emergence of broadleaf and grassy weeds. The persistence of this herbicide is influenced by the metabolic action of habituated native microor-ganisms. This study provides information on the occurrence of atrazine mineralizing bacterial strains with faster me-tabolizing ability. The enrichment cultures were tested for the biodegradation of atrazine by high-performance liquid chromatography (HPLC) and mass spectrometry. Nine cultures JS01.Deg01 to JS09.Deg01 were identified as the degrader of atrazine in the enrichment culture. The three isolates JS04.Deg01, JS07.Deg01, and JS08.Deg01 were identified as efficient atrazine metabolizers. Isolates JS04.Deg01 and JS07.Deg01 produced hydroxyatrazine (HA) N-isopropylammelide and cyanuric acid by dealkylation reaction. The isolate JS08.Deg01 generated deethylatrazine (DEA), deisopropylatrazine (DIA), and cyanuric acid by N-dealkylation in the upper degradation pathway and later it incorporated cyanuric acid in their biomass by the lower degradation pathway. The optimum pH for degrading atrazine by JS08.Deg01 was 7.0 and 16S rDNA phylogenetic typing identified it as Enterobacter cloacae strain JS08.Deg01. The highest atrazine mineralization was observed in case of isolate JS08.Deg01, where an ample amount of trzD mRNA was quantified at 72 h of incubation with atrazine. Atrazine bioremediating isolate E. cloacae strain JS08.Deg01 could be the better environmental remediator of agricultural soils and the crop fields contaminated with atrazine could be the source of the efficient biodegrading microbial strains for the environmental cleanup process.

  19. Comparison of bacterial culture and polymerase chain reaction (PCR) for the detection of F. tularensis subsp. holarctica in wild animals.

    Science.gov (United States)

    Sting, Reinhard; Runge, Martin; Eisenberg, Tobias; Braune, Silke; Müller, Wolfgang; Otto, Peter

    2013-01-01

    Detection of the zoonotic pathogen Francisella tularensis subsp. holarctica (EF tularensis) in wild animals with culture techniques as well as polymerase chain reaction were compared and discussed on the basis of the investigation of 60 animals. The samples originated from 55 European brown hares (Lepus europaeus), two red foxes (Vulpes vulpes) and one each from a wild rabbit (Oryctolagus cuniculus), a European beaver (Castor fiber), and a lemur (Lemur catta). When comparing the growth of 28 F. tularensis isolates on the cysteine blood agar and the modified Martin-Lewis-agar used in this study, cultivation was successful for 26 isolates on both media, but for two isolates only on the cysteine blood agar. Out of 43 carcasses 19 tested positive in bacteriological culture and PCR. Two culture positive samples of tonsils originating from foxes could not be confirmed by PCR, although PCR was positive in 22 samples that missed growth of F. tularensis. Comparative studies on cultural detection of E. tularensis were performed on samples of 16 hares from lung, spleen, liver and gut and in one case with a peritoneal swab. In at least one of these localizations cultivation of the pathogen was successful. Detection rate was reduced to 94% (15 of 16 hares) considering only the results of the cultures of the lungs and spleens. For a sensitive and rapid detection of F. tularensis subsp. holarctica, the PCR is a suitable method thereby avoiding hazardous multiplying of the pathogen. However, cultivation of F. tularensis is often a prerequisite for further studies on antibiotic resistance patterns of the pathogen, molecular epidemiological and pathological analyses of tularaemia.

  20. Preparation of recombinant firefly luciferase by a simple and rapid expression and purification method and its application in bacterial detection

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A simple and rapid expression and purification method of recombinant firefly luciferase was developed for bacteria detection. A modified luciferase gene from North American firefly Photinus pyralis was cloned into pET28a expression vector and the recombinant protein was produced in Escherichia coli BL21. The recombinant luciferase,equipped with a polyhistidine affinity tag,was purified by immobilized metal ion affinity chromatography (IMAC). The approach generated an abundant expression and an efficient pur...

  1. Detection of entero viruses and hepatitis A in treated wastewater and Correlation between viral and bacterial contamination

    International Nuclear Information System (INIS)

    The main human viruses likely to contaminate waste water are Non-enveloped viruses able to resist in the environment, so essentially the viruses presenting an enteric cycle of multiplication. Many of these viruses, namely entero virus, hepatitis Avirus are excreted in the saddles of patients or of carriers and meet in waste water. To fight against the viral risk it is necessary to have a methodology allowing the control and the surveillance of virological and Hydric contamination. For the revealing of enteric virus, the reference technique remains the isolation on cellular culture. However, the disadvantage of this technique is the fact that it is difficult for certain viruses. Thus, the rise of molecular biology allowed the focusing of reliable and significant methods for detection of the enteric viruses in the environmental takings. The aim of this work was to detect hepatitis A virus and entero virus in waste water. A total of 20 samples were concentrated then precipitated by Polyethylene glycol 6000 according to the method of EPA. Extraction and purification of the viral ARN are made by the Kit QIAmp Viral RNA (Qiagen). The analysis of nucleic acids extracted by RT-PCR allowed to detect Entero virus with a 15 pour cent frequency (3/20) and 10 pour cent (2/20) for the hepatitis A virus.

  2. A multi-channel bioluminescent bacterial biosensor for the on-line detection of metals and toxicity. Part II: technical development and proof of concept of the biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Charrier, Thomas; Thouand, Gerald [UMR CNRS 6144 GEPEA, CBAC, Nantes University, PRES UNAM, Campus de la Courtaisiere-IUT, La Roche-sur-Yon cedex (France); Chapeau, Cyrille [Biolumine, Biokar Diagnostic, Rue des Quarante Mines ZAC de Ther-Allonne, Beauvais Cedex (France); Bendria, Loubna; Daniel, Philippe [UMR CNRS 6087 LPEC, Universite du Maine, Av Olivier Messiaen, Le Mans cedex 9 (France); Picart, Pascal [UMR CNRS 6613 IAM-LAUM, Ecole Nationale des Ingenieurs du Mans, Universite du Maine, Le Mans Cedex 9 (France)

    2011-05-15

    This research study deals with the on-line detection of heavy metals and toxicity within the context of environmental pollution monitoring. It describes the construction and the proof of concept of a multi-channel bioluminescent bacterial biosensor in immobilized phase: Lumisens3. This new versatile device, designed for the non-stop analysis of water pollution, enables the insertion of any bioluminescent strains (inducible or constitutive), immobilized in a multi-well removable card. The technical design of Lumisens3 has benefited from both a classical and a robust approach and includes four main parts: (1) a dedicated removable card contains 64 wells, 3 mm in depth, arranged in eight grooves within which bacteria are immobilized, (2) this card is incubated on a Pelletier block with a CCD cooled camera on top for bioluminescence monitoring, (3) a fluidic network feeds the card with the sample to be analyzed and finally (4) a dedicated computer interface, BIOLUX 1.0, controls all the elements of the biosensor, allowing it to operate autonomously. The proof of concept of this biosensor was performed using a set of four bioluminescent bacteria (Escherichia coli DH1 pBzntlux, pBarslux, pBcoplux, and E. coli XL1 pBfiluxCDABE) in the on-line detection of CdCl{sub 2} 0.5 {mu}M and As{sub 2}O{sub 3} 5 {mu}M from an influent. When considering metals individually, the ''fingerprints'' from the biosensor were as expected. However, when metals were mixed together, cross reaction and synergistic effects were detected. This biosensor allowed us to demonstrate the simultaneous on-line cross detection of one or several heavy metals as well as the measurement of the overall toxicity of the sample. (orig.)

  3. RNA Detection in Live Bacterial Cells Using Fluorescent Protein Complementation Triggered by Interaction of Two RNA Aptamers with Two RNA-Binding Peptides

    Directory of Open Access Journals (Sweden)

    Charles R. Cantor

    2011-03-01

    Full Text Available Many genetic and infectious diseases can be targeted at the RNA level as RNA is more accessible than DNA. We seek to develop new approaches for detection and tracking RNA in live cells, which is necessary for RNA-based diagnostics and therapy. We recently described a method for RNA visualization in live bacterial cells based on fluorescent protein complementation [1-3]. The RNA is tagged with an RNA aptamer that binds an RNA-binding protein with high affinity. This RNA-binding protein is expressed as two split fragments fused to the fragments of a split fluorescent protein. In the presence of RNA the fragments of the RNA-binding protein bind the aptamer and bring together the fragments of the fluorescent protein, which results in its re-assembly and fluorescence development [1-3]. Here we describe a new version of the RNA labeling method where fluorescent protein complementation is triggered by paired interactions of two different closely-positioned RNA aptamers with two different RNA-binding viral peptides. The new method, which has been developed in bacteria as a model system, uses a smaller ribonucleoprotein complementation complex, as compared with the method using split RNA-binding protein, and it can potentially be applied to a broad variety of RNA targets in both prokaryotic and eukaryotic cells. We also describe experiments exploring background fluorescence in these RNA detection systems and conditions that improve the signal-to-background ratio.

  4. A GFP-based bacterial biosensor with chromosomally integrated sensing cassette for quantitative detection of Hg(II) in environment

    Institute of Scientific and Technical Information of China (English)

    Himanshu Priyadarshi; Absar Alam; Gireesh-Babu P; Rekha Das; Pankaj Kishore; Shivendra Kumar; Aparna Chaudhari

    2012-01-01

    A mercury biosensor was constructed by integrating biosensor genetic elements into E.coli JM109 chromosome in a single copy number,using the attP/attB recombination mechanism of λ phage.The genetic elements used include a regulatory protein gene (merR) along with operator/promoter (O/P) derived from the mercury resistance operon from pDU1358 plasmid of Serratia marcescens.The expression of reporter gene gfp is also controlled by merR/O/P.Integration of the construct into the chromosome was done to increase the stability and precision of the biosensor.This biosensor could detect Hg(Ⅱ) ions in the concentration range of 100-1700 mnol/L,and manifest the result as the expression of GFP.The GFP expression was significantly different (P ≤ 0.05) for each concentration of inducing Hg(Ⅱ) ions in the detection range,which reduces the chances of misinterpretation of results.A model using regression method was also derived for the quantification of the concentration of Hg(Ⅱ) in water samples.

  5. Clinical Application of Detection of PCT in Bacterial Infection%PCT检测在细菌性感染中的临床应用

    Institute of Scientific and Technical Information of China (English)

    林琼花

    2015-01-01

    Objective To investigate the clinical application of detection of PCT in bacterial infection. Methods A retro-spective analysis, select our hospital during March 2014 - June 2015, the clinical data of 68 patients with bacterial infec-tions were treated as the research object, according to the presence of sepsis patients divided the patients into two groups, sepsis and sepsis group, including 44 patients with sepsis group, 24 cases of sepsis patients. Wan Fu fly immunofluores-cence measurement instrument has been applied to the determination of serum PCT in patients with positive rate, comparing the gram-positive bacteria and gram-negative bacteria of PCT in the difference of positive rate. Results PCT acuity 0.5 ng/mL for positive threshold, PCT positive rate is 88.24%;Different pathogenic bacteria caused by the infection rate of positive of PCT no obvious differences between groups, P>0.05, there was no statistical significance; PCT acuity 2.0 ng/mL for sepsis positive threshold, found that the content of PCT in patients with sepsis group was obviously higher than that of the sepsis patients, by statistical comparison,P0.05);以PCT≥2.0 ng/mL为脓毒症的阳性阈值,发现脓毒症组患者PCT含量明显高于非脓毒症组患者,差异有统计学意义(P<0.05);PCT对脓毒症的临床诊断特异性和灵敏度分别为:100豫、81.81豫。结论血清PCT是鉴别细菌感染引发脓毒症的较为准确的检测手段。

  6. Detection and differentiation of bacterial spores in a mineral matrix by Fourier transform infrared spectroscopy (FTIR and chemometrical data treatment

    Directory of Open Access Journals (Sweden)

    Brandes Ammann Andrea

    2011-07-01

    Full Text Available Abstract Background Fourier transform infrared spectroscopy (FTIR has been used as analytical tool in chemistry for many years. In addition, FTIR can also be applied as a rapid and non-invasive method to detect and identify microorganisms. The specific and fingerprint-like spectra allow - under optimal conditions - discrimination down to the species level. The aim of this study was to develop a fast and reproducible non-molecular method to differentiate pure samples of Bacillus spores originating from different species as well as to identify spores in a simple matrix, such as the clay mineral, bentonite. Results We investigated spores from pure cultures of seven different Bacillus species by FTIR in reflection or transmission mode followed by chemometrical data treatment. All species investigated (B. atrophaeus, B. brevis, B. circulans, B. lentus, B. megaterium, B. subtilis, B. thuringiensis are typical aerobic soil-borne spore formers. Additionally, a solid matrix (bentonite and mixtures of benonite with spores of B. megaterium at various wt/wt ratios were included in the study. Both hierarchical cluster analysis and principal component analysis of the spectra along with multidimensional scaling allowed the discrimination of different species and spore-matrix-mixtures. Conclusions Our results show that FTIR spectroscopy is a fast method for species-level discrimination of Bacillus spores. Spores were still detectable in the presence of the clay mineral bentonite. Even a tenfold excess of bentonite (corresponding to 2.1 × 1010 colony forming units per gram of mineral matrix still resulted in an unambiguous identification of B. megaterium spores.

  7. Detection of bacterial endotoxin in Xingnaojing injection with Tachypleus Amebocyte lysate%鲎试剂检查醒脑静注射液细菌内毒素的探讨

    Institute of Scientific and Technical Information of China (English)

    叶树林; 王晓蕾

    2011-01-01

    Objective To study the method for the detection of bacterial endotoxin in Xingnaojing injection with Tachypleus Amebocyte lysate(TAL). Methods Experiments were performed according to the bacterial endotoxin tests covered in Chinese Pharmacopeia 2005(part 2). Results Xingnaojing injection did not interfere with its gel reaction to the bacterial endotoxin when it was diluted 10-fold. Conclusion Bacterial endotoxin test can be used to detect bacterial endotoxin in Xingnaojing injection.%目的 探讨用鲎试剂检查醒脑静注射液细菌内毒素方法.方法 根据2005年版Ⅱ部收载的细菌内毒素检查法的要求进行实验.结果 醒脑静注射液经10倍稀释时不干扰鲎试剂与细菌内毒素的凝胶反应.结论 细菌内毒素检查法适用于检测醒脑静注射液的内毒素.

  8. Finding New Enzymes from Bacterial Physiology: A Successful Approach Illustrated by the Detection of Novel Oxidases in Marinomonas mediterranea

    Directory of Open Access Journals (Sweden)

    Antonio Sanchez-Amat

    2010-03-01

    Full Text Available The identification and study of marine microorganisms with unique physiological traits can be a very powerful tool discovering novel enzymes of possible biotechnological interest. This approach can complement the enormous amount of data concerning gene diversity in marine environments offered by metagenomic analysis, and can help to place the activities associated with those sequences in the context of microbial cellular metabolism and physiology. Accordingly, the detection and isolation of microorganisms that may be a good source of enzymes is of great importance. Marinomonas mediterranea, for example, has proven to be one such useful microorganism. This Gram-negative marine bacterium was first selected because of the unusually high amounts of melanins synthesized in media containing the amino acid L-tyrosine. The study of its molecular biology has allowed the cloning of several genes encoding oxidases of biotechnological interest, particularly in white and red biotechnology. Characterization of the operon encoding the tyrosinase responsible for melanin synthesis revealed that a second gene in that operon encodes a protein, PpoB2, which is involved in copper transfer to tyrosinase. This finding made PpoB2 the first protein in the COG5486 group to which a physiological role has been assigned. Another enzyme of interest described in M. mediterranea is a multicopper oxidase encoding a membrane-associated enzyme that shows oxidative activity on a wide range of substrates typical of both laccases and tyrosinases. Finally, an enzyme very specific for L-lysine, which oxidises this amino acid in epsilon position and that has received a new EC number (1.4.3.20, has also been described for M. mediterranea. Overall, the studies carried out on this bacterium illustrate the power of exploring the physiology of selected microorganisms to discover novel enzymes of biotechnological relevance.

  9. Increased accuracy of the carbon-14 D-xylose breath test in detecting small-intestinal bacterial overgrowth by correction with the gastric emptying rate

    International Nuclear Information System (INIS)

    The aim of this study was to determine whether the accuracy of 14C-D-xylose breath test for detecting bacterial overgrowth can be increased by correction with the gastric emptying rate of 14C-D-xylose. Ten culture-positive patients and ten culture-negative controls were included in the study. Small-intestinal aspirates for bacteriological culture were obtained endoscopically. A liquid-phase gastric emptying study was performed simultaneously to assess the amount of 14C-D-xylose that entered the small intestine. The results of the percentage of expired 14CO2 at 30 min were corrected with the amount of 14C-D-xylose that entered the small intestine. There were six patients in the culture-positive group with a 14CO2 concentration above the normal limit. Three out of four patients with initially negative results using the uncorrected method proved to be positive after correction. All these three patients had prolonged gastric emptying of 14C-D-xylose. When compared with cultures of small-intestine aspirates, the sensitivity and specificity of the uncorrected 14C-D-xylose breath test were 60% and 90%, respectively. In contrast, the sensitivity and specificity of the corrected 14C-D-xylose breath test improved to 90% and 100%, respectively. (orig./MG)

  10. Bacterial Vaginosis

    Science.gov (United States)

    ... 586. Related Content STDs during Pregnancy Fact Sheet Pregnancy and HIV, Viral Hepatitis, and STD Prevention Pelvic Inflammatory Disease ( ... Bacterial Vaginosis (BV) Chlamydia Gonorrhea Genital Herpes Hepatitis HIV/AIDS & STDs Human Papillomavirus ... STDs See Also Pregnancy Reproductive ...

  11. Bacterial Meningitis

    Science.gov (United States)

    ... Schedules Preteen & Teen Vaccines Meningococcal Disease Sepsis Bacterial Meningitis Recommend on Facebook Tweet Share Compartir On this ... serious disease. Laboratory Methods for the Diagnosis of Meningitis This manual summarizes laboratory methods used to isolate, ...

  12. Evaluation of a fluorescence-labelled oligonucleotide tide probe targeting 23S rRNA for in situ detection of Salmonella serovars in paraffin-embedded tissue sections and their rapid identification in bacterial smears

    DEFF Research Database (Denmark)

    Nordentoft, Steen; Christensen, H.; Wegener, Henrik Caspar

    1997-01-01

    A method for the detection of Salmonella based on fluorescence in situ hybridization (FISH) has been developed and applied for the direct detection of Salmonella in pure cultures and in formalin-fixed, paraffin-embedded tissue sections. On the basis of the 23S rRNA gene sequences representing all...... with the probe. The probe did not hybridize to serovars from subspecies IIIa (S. arizonae) or to S. bongori. No cross-reaction to 64 other strains of the family Enterobacteriaceae or 18 other bacterial strains outside this family was observed. The probe was tested with sections of formalin-fixed, paraffin......-embedded tissue from experimentally infected mice or from animals with a history of clinical salmonellosis. In these tissue sections the probe hybridized specifically to Salmonella serovars, allowing for the detection of single bacterial cells. The development of a fluorescence-labelled specific oligonucleotide...

  13. Research progress in the detecting methods of bacterial risk factors in food%食品中细菌危害因子检测进展

    Institute of Scientific and Technical Information of China (English)

    胡晓清; 潘露; 王小元

    2011-01-01

    The pollution of pathogenic bacteria is a serious threat to food safety.There are many types of risk factors,including not only a variety of bacterial toxins, but also some cell components such as flagella that participate in the process of host infection.Recently,many novel detection methods for the risk factors produced by the pathogenic bacteria in food have been developed,along with the developments and integrations of polymerase chain reaction technology,enzyme-linked immunosorbent assay and nanogold labeling technique.In the present paper,the methods for analyzing the risk factors of Escherichia coli, Clostridium botulinum, Bacillus cereus, Staphylococcus sp. And etc. Were summarized and compared. Furthermore, on the basis of analysis methods reported,some new prospects on the rapid detection of trace amount of risk factors were discussed.%致病细菌污染是影响食品安全的重要因素.细菌危害因子种类繁多,既包括各种细菌毒素,也包括参与宿主侵染过程的细胞组分,如鞭毛等.随着聚合酶链式反应、酶联免疫吸附分析法和纳米金标记技术的交叉融合,近年来涌现了一批新的检测食品中细菌危害因子的方法.本文对大肠杆菌、肉毒梭菌、蜡状芽孢杆菌、葡萄球菌等的危害因子的分析方法进行了综述和比较,并在此基础上讨论了其快速超微量检测的研究方向.

  14. ORIGINAL ARTICLE: Detection of β-Lactamase Activity in Various Clinical Bacterial Isolates by Three Different Methods and its Correlation with Drug Resistance.

    Directory of Open Access Journals (Sweden)

    Sanjay M Wavare

    2012-07-01

    Full Text Available Background: β-lactams such as penicillins are the most widely used antibiotics, and β-lactamases are the greatest source of resistance to penicillins. Aims and Objectives: To study β-lactamase production in clinical isolates of family Enterobacteriaceae, P. aeruginosa and Staphylococci by three different methods and to correlate its potential with drug resistance; with an endeavour to evaluate convenient and economical method duly supported by relevant Minimum Inhibitory Concentration (MIC studies. Material and Methods: Total 240 clinical isolates (Gram-negative bacilli-191, staphylococci-49 were subjected to antimicrobial susceptibility testing by Kirby-Bauer disk diffusion method and MIC for ampicillin and penicillin was determined by agar dilution method. β-lactamase was detected by broth acidometric, iodometric cell suspension and microbiological method. Results: Multidrug resistance was observed in more than 90% isolates. One hundred and ninety Gram-negative bacilli were resistant to ampicillin and 47 staphylococcal isolates were resistant to both penicillin and ampicillin. Though microbiological method gave highest positive results 210 (87.5%, iodometric method could detect β-lactamase in apparently sensitive isolates as well giving satisfactory [207 (86.25%] comparable results. Conclusion: In view of the noted bacterial resistance, tests for β-lactamase should be carried out on a routine basis for an early implementation of appropriate antimicrobial therapy. Iodometric method is eminently convenient, economical and reliable method. Isolates showing MIC <0.125µg/ml for penicillin and MIC <8µg/ml for ampicillin should be checked for β-lactamase production.

  15. Disposable Hygiene Products Detection Analysis of Bacterial Contamination%一次性卫生用品细菌污染的检测分析

    Institute of Scientific and Technical Information of China (English)

    雷少华

    2016-01-01

    目的:分析一次性卫生用品细菌污染的卫生质量。方法择取本地区2013—2015年一次性使用卫生用品的工作环境、产品污染情况等进行调查与统计。结果2013—2015年一次性卫生用品质量检测中,皮肤抑菌剂、卫生湿巾、婴幼儿纸尿裤、卫生巾、餐巾纸等物品的检测合格率均较高;车间空气、工作台表面的检测合格率均较高;致病性化脓菌与大肠菌群的检测合格率均较高。结论2013—2015年该地区关于一次性卫生用品的细菌污染情况呈现逐渐改善的趋势,提示相关部门应加大监管力度,保证一次性卫生用品的质量安全。%Objective To analyze the disposable sanitary products of bacterial contamination and health quality. Methods Will pick the region in 2013-2015 product of disposable sanitary products, environment pollution investigation and statis-tics, etc. Results The 2013-2015 disposable sanitary products quality detection, skin antibacterial agent, hygiene wipes, baby diapers, sanitary napkins, napkin, etc. The article detection qualified rate is higher; workplace air, surface detection qualified rate is higher; pathogenic pyogenic bacteria and coliform group detection qualified rate is higher. Conclusion The region in 2013-2015 of disposable sanitary products of bacteria pollution situation shows the tendency of gradually improve, prompt the relevant departments should step up supervision, guarantee the quality of disposable sanitary products safety.

  16. Bacterial carbonatogenesis

    International Nuclear Information System (INIS)

    Several series of experiments in the laboratory as well as in natural conditions teach that the production of carbonate particles by heterotrophic bacteria follows different ways. The 'passive' carbonatogenesis is generated by modifications of the medium that lead to the accumulation of carbonate and bicarbonate ions and to the precipitation of solid particles. The 'active' carbonatogenesis is independent of the metabolic pathways. The carbonate particles are produced by ionic exchanges through the cell membrane following still poorly known mechanisms. Carbonatogenesis appears to be the response of heterotrophic bacterial communities to an enrichment of the milieu in organic matter. The active carbonatogenesis seems to start first. It is followed by the passive one which induces the growth of initially produced particles. The yield of heterotrophic bacterial carbonatogenesis and the amounts of solid carbonates production by bacteria are potentially very high as compared to autotrophic or chemical sedimentation from marine, paralic or continental waters. Furthermore, the bacterial processes are environmentally very ubiquitous; they just require organic matter enrichment. Thus, apart from purely evaporite and autotrophic ones, all Ca and/or Mg carbonates must be considered as from heterotrophic bacterial origin. By the way, the carbon of carbonates comes from primary organic matter. Such considerations ask questions about some interpretations from isotopic data on carbonates. Finally, bacterial heterotrophic carbonatogenesis appears as a fundamental phase in the relationships between atmosphere and lithosphere and in the geo-biological evolution of Earth. (author)

  17. Evaluation of the Limulus amoebocyte lysate test in conjunction with a gram negative bacterial plate count for detecting irradiation of chicken

    International Nuclear Information System (INIS)

    A study to evaluate the potential of the Limulus amoebocyte lysate (LAL) test in conjunction with a Gram negative bacterial (GNB) plate count for detecting the irradiation of chicken is described. Preliminary studies demonstrated that chickens irradiated at an absorbed dose of 2.5 kGy could be differentiated from unirradiated birds by measuring levels of endotoxin and of numbers of GNB on chicken skin. Irradiated birds were found to have endotoxin levels similar to those found in unirradiated birds but significantly lower numbers of GNB. In a limited study the test was found to be applicable to birds from different processors. The effect of temperature abuse on the microbiological profile, and thus the efficacy of the test, was also investigated. After temperature abuse, the irradiated birds were identifiable at worst up to 3 days after irradiation treatment at the 2.5 kGy level and at best some 13 days after irradiation. Temperature abuse at 150C resulted in rapid recovery of surviving micro-organisms which made differentiation of irradiated and unirradiated birds using this test unreliable. The microbiological quality of the bird prior to irradiation treatment also affected the test as large numbers of GNB present on the bird prior to irradiation treatment resulted in larger numbers of survivors. In addition, monitoring the developing flora after irradiation treatment amd during subsequent chilled storage also aided differentiation of irradiated and unirradiated birds. Large numbers of yeast and Gram positive cocci were isolated from irradiated carcasses whereas Gram negative oxidative rods were the predominant spoilage flora on unirradiated birds. (author)

  18. Evaluation of the Limulus amoebocyte lysate test in conjunction with a gram negative bacterial plate count for detecting irradiation of chicken

    Energy Technology Data Exchange (ETDEWEB)

    Scotter, S.L.; Wood, R.; McWeeny, D.J. (Ministry of Agriculture, Fisheries and Food, Norwich (UK). Food Science Lab.)

    1990-01-01

    A study to evaluate the potential of the Limulus amoebocyte lysate (LAL) test in conjunction with a Gram negative bacterial (GNB) plate count for detecting the irradiation of chicken is described. Preliminary studies demonstrated that chickens irradiated at an absorbed dose of 2.5 kGy could be differentiated from unirradiated birds by measuring levels of endotoxin and of numbers of GNB on chicken skin. Irradiated birds were found to have endotoxin levels similar to those found in unirradiated birds but significantly lower numbers of GNB. In a limited study the test was found to be applicable to birds from different processors. The effect of temperature abuse on the microbiological profile, and thus the efficacy of the test, was also investigated. After temperature abuse, the irradiated birds were identifiable at worst up to 3 days after irradiation treatment at the 2.5 kGy level and at best some 13 days after irradiation. Temperature abuse at 15{sup 0}C resulted in rapid recovery of surviving micro-organisms which made differentiation of irradiated and unirradiated birds using this test unreliable. The microbiological quality of the bird prior to irradiation treatment also affected the test as large numbers of GNB present on the bird prior to irradiation treatment resulted in larger numbers of survivors. In addition, monitoring the developing flora after irradiation treatment amd during subsequent chilled storage also aided differentiation of irradiated and unirradiated birds. Large numbers of yeast and Gram positive cocci were isolated from irradiated carcasses whereas Gram negative oxidative rods were the predominant spoilage flora on unirradiated birds. (author).

  19. Detection and investigation of foodborne bacterial pathogens in Ningbo%宁波地区食品中致病菌污染物检测与调查

    Institute of Scientific and Technical Information of China (English)

    盛冬萍; 谢益君; 陈米娜; 徐景野

    2013-01-01

    Objective objective To understand the presence,contamination and cross contamination of foodborne bacterial pathogens in Ningbo city,provide basis for foodborne disease control,and trace the source of foodborne disease.Methods Strains were detected directly or after enrichment with biochemistry and API method,and subtyped with serum agglutination method.Antibiotic resistance and relative genes were detected with K-B method and PCR method respectively.Results 2 331 (7 species and 12 types) strains were detected from 6 812 food samples and the detection rate is 34.22% (2 331/6 812).The prevalent pathogens were Vibrio parahaemolyticus,and the detection rate was significantly different from the other types (P < 0.005).Vibrio parahaemolyticus could be classified into 10 sero-groups,and O6 and O5 were proved as the prevalent sero-groups.Most of the pathogens were sensitive to antibiotics.Three strains of Aeromonas were found multi-resistant with aacc resistance gene.Conclusion Various distribution was proved in foodborne bacteria in Ningbo.Contamination of foodborne pathogens was a major factor of foodborne diseases.Vibrio parahaemolyticus was the prevalent pathogenic bacteria.Most of the pathogens were sensitive to antibiotics.Bacteria with aacc resistance gene were found,which should raise concerns to control the spread of the resistant strains through rational administration of antibiotics and resistance surveillance.%目的 了解宁波地区食品中携带或污染的致病菌,为控制食源性疾病提供依据.方法 致病菌检测采用直接分离与增菌分离相结合的方法;细菌鉴定采用生化筛检和API等方法;血清分型采用诊断血清凝集法;药敏试验采用K-B法;采用PCR检测耐药基因.结果 从6 812份食品标本中检出致病菌7类12种,共2 331株,检出率为34.22%,以副溶血性弧菌检出率最高,与其他病原菌检出率比较差异有统计学意义(P<0.005).主要流行株

  20. Bacterial and fungal genome detection PCR/NAT: discussion of the Mai 2015 distribution for external quality assessment of nucleic acid-based protocols in diagnostic medical microbiology by INSTAND e.V.

    OpenAIRE

    Reischl, U.; W. Schneider; Ehrenschwender, M; Hiergeist, A; Maaß, M.; Baier, M; Straube, E; Frangoulidis, D.; Grass, G.; von Buttlar, H; Fingerle, V.; A Sing; Jacobs, E; Reiter-Owona, I; Anders, A.

    2015-01-01

    This contribution provides an analysis report of the recent proficiency testing scheme "Bacterial and Fungal Genome Detection (PCR/NAT)". It summarizes some benchmarks and the overall assessment of results reported by all of the participating laboratories. A highly desired scheme for external quality assessment (EQAS) of molecular diagnostic methods in the field of medical microbiology was activated in 2002 by the German Society of Hygiene and Microbiology (DGHM) and is now organized by INST...

  1. EFFECTIVENESS OF CLOSTRIDIUM ISOLATES ON AEROPONICALLY CULTIVATED POTATO TO PROTECT AGAINST RALSTONIA SOLANACEARUM (BACTERIAL WILT) AND PCR DETECTION ON LATEN INFECTION ON TUBERS.

    OpenAIRE

    Baharuddin.

    2012-01-01

    Aeroponic technology was used to optimize production of potato mini tubers. Several adventage was the production 5-10 times higher and tuber size was bigger than covensional methods, but unfortunatelly some times yield loss was present caused by bacterial wilt Ralstonia solanacearum. Although not all of plants were died and some of plants still produce tubers, but laten infection of bacterial wilt was occured. Early observation on microbes diversity on healthy and on infected plants ...

  2. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... is the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental parameters......, which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to significantly...

  3. Bacterial lipases

    NARCIS (Netherlands)

    Jaeger, Karl-Erich; Ransac, Stéphane; Dijkstra, Bauke W.; Colson, Charles; Heuvel, Margreet van; Misset, Onno

    1994-01-01

    Many different bacterial species produce lipases which hydrolyze esters of glycerol with preferably long-chain fatty acids. They act at the interface generated by a hydrophobic lipid substrate in a hydrophilic aqueous medium. A characteristic property of lipases is called interfacial activation, mea

  4. Numerical Analysis of Perturbation Forces of GPS and BDS Satellites%GPS/BDS卫星摄动力数值分析

    Institute of Scientific and Technical Information of China (English)

    宋传峰; 朱李忠; 赵忠海; 张洪文

    2016-01-01

    由精密星历利用拉格朗日插值公式求二次导数的方法计算了卫星在J2000.0惯性坐标系下的总加速度;利用现有的力模型计算了地球中心引力,地球非球形摄动力,太阳、月球和其他行星的摄动力,地球固体潮摄动力,相对论效应摄动力对GPS/BDS卫星所产生的加速度数值大小;利用G-file里的BERNE太阳光压模型参数计算了GPS卫星太阳光压摄动加速度大小;对GPS/BDS卫星所受的不同摄动力进行了数值分析,对同一摄动力对不同类型卫星的影响进行了数值分析比较。结果表明,现有力模型与GPS/BDS卫星所受的实际作用力仍有一定的差距,不同类型卫星所受摄动力有明显差异,在精密定轨的实际应用中应根据不同类型卫星建立合适的力学模型。%This paper calculated the total acceleration of the satellite in J2000.0 inertial coordinate system using the second derivative of Lagrange's interpolation formula by the precise ephemeris.Based on mechanical models, this paper computed the acceleration of GPS and BDS satellites due to the gravity of Earth's center and the perturbation forces of the Earth's non-spherical, the sun, the moon, other planets, Earth solid tide and the relativity.Using the BERNE solar pressure module parameters in G-file, this paper al-so computed the solar radiation pressure perturbation acceleration of GPS satellite.After that, we made numerical analysis and com-parison of different perturbation forces and different types of satellites.It's concluded that the difference between mechanical models and true forces of satellite is evident.It's also concluded that different types of satellite suffered significant difference in perturbation forces especially for BDS GEO satellite due to the influence of maneuver force.Therefore, in the practical application of precise orbit determination, establish a suitable mechanical model is needed.

  5. A drift line bias estimator: ARMA-based filter or calibration method, and its application in BDS/GPS-based attitude determination

    Science.gov (United States)

    Liang, Zhang; Yanqing, Hou; Jie, Wu

    2016-06-01

    The multi-antenna synchronized receiver (using a common clock) is widely applied in GNSS-based attitude determination (AD) or terrain deformations monitoring, and many other applications, since the high-accuracy single-differenced carrier phase can be used to improve the positioning or AD accuracy. Thus, the line bias (LB) parameter (fractional bias isolating) should be calibrated in the single-differenced phase equations. In the past decades, all researchers estimated the LB as a constant parameter in advance and compensated it in real time. However, the constant LB assumption is inappropriate in practical applications because of the physical length and permittivity changes of the cables, caused by the environmental temperature variation and the instability of receiver-self inner circuit transmitting delay. Considering the LB drift (or colored LB) in practical circumstances, this paper initiates a real-time estimator using auto regressive moving average-based (ARMA) prediction/whitening filter model or Moving average-based (MA) constant calibration model. In the ARMA-based filter model, four cases namely AR(1), ARMA(1, 1), AR(2) and ARMA(2, 1) are applied for the LB prediction. The real-time relative positioning model using the ARMA-based predicting LB is derived and it is theoretically proved that the positioning accuracy is better than the traditional double difference carrier phase (DDCP) model. The drifting LB is defined with a phase temperature changing rate integral function, which is a random walk process if the phase temperature changing rate is white noise, and is validated by the analysis of the AR model coefficient. The auto covariance function shows that the LB is indeed varying in time and estimating it as a constant is not safe, which is also demonstrated by the analysis on LB variation of each visible satellite during a zero and short baseline BDS/GPS experiment. Compared to the DDCP approach, in the zero-baseline experiment, the LB constant

  6. Detection of carboxylesterase and esterase activity in culturable gut bacterial flora isolated from diamondback moth, Plutella xylostella (Linnaeus, from India and its possible role in indoxacarb degradation

    Directory of Open Access Journals (Sweden)

    Shanivarsanthe Leelesh Ramya

    2016-06-01

    Full Text Available Abstract Diamondback moth (DBM, Plutella xylostella (Linnaeus, is a notorious pest of brassica crops worldwide and is resistant to all groups of insecticides. The insect system harbors diverse groups of microbiota, which in turn helps in enzymatic degradation of xenobiotic-like insecticides. The present study aimed to determine the diversity of gut microflora in DBM, quantify esterase activity and elucidate their possible role in degradation of indoxacarb. We screened 11 geographic populations of DBM in India and analyzed them for bacterial diversity. The culturable gut bacterial flora underwent molecular characterization with 16S rRNA. We obtained 25 bacterial isolates from larvae (n = 13 and adults (n = 12 of DBM. In larval gut isolates, gammaproteobacteria was the most abundant (76%, followed by bacilli (15.4%. Molecular characterization placed adult gut bacterial strains into three major classes based on abundance: gammaproteobacteria (66%, bacilli (16.7% and flavobacteria (16.7%. Esterase activity from 19 gut bacterial isolates ranged from 0.072 to 2.32 µmol/min/mg protein. Esterase bands were observed in 15 bacterial strains and the banding pattern differed in Bacillus cereus – KC985225 and Pantoea agglomerans – KC985229. The bands were characterized as carboxylesterase with profenofos used as an inhibitor. Minimal media study showed that B. cereus degraded indoxacarb up to 20%, so it could use indoxacarb for metabolism and growth. Furthermore, esterase activity was greater with minimal media than control media: 1.87 versus 0.26 µmol/min/mg protein. Apart from the insect esterases, bacterial carboxylesterase may aid in the degradation of insecticides in DBM.

  7. Detection of Bacterial Endotoxins in Propacetamol Hydrochloride for Injection by Tachypleus Amebocyte Lysate Test%鲎试剂法检测注射用盐酸丙帕他莫中细菌内毒素

    Institute of Scientific and Technical Information of China (English)

    罗丽萍; 郭成希; 黄砚青

    2011-01-01

    Objective: To establish a method for detection of bacterial endotoxins in propacetainol hydrochloride for injection. Method: The experiments were carried out according to the bacterial endotoxins test specified in appendix XI E,volume two,Chinese pharmacopoeia 2010 edition. Result: Samples with the concentration of 5.0 mg·ml-1 had inhibitive effect on the bacterial endntoxins test,however the interference was eliminated when the samples were diluted to the concentration of 2. 5 mg·ml-1 ,detected hy tarhypleus ameboeyte lysates with the sensitivity of 0. 25 EU·ml-1. Conclusion: Tachypleus amebocyte lysate test is feasible for detecting bacterial endotoxins in propacetamol hydrochloride for injection.%目的:考察鲎试剂方法检测注射用盐酸丙帕他莫中细菌内毒素的可行性.方法:参照《中国药典》2010年版(二部)附录ⅪE细菌内毒素检查法对注射用盐酸丙帕他莫进行细菌内毒素检测.结果:质量浓度为5.0 mg·ml-1的样品溶液对凝集反应有抑制作用,质量浓度稀释至2.5 mg·ml-1时,用灵敏度λ为0.25 EU· ml-的鲎试剂进行试验,干扰作用消失.结论:注射用盐酸丙帕他莫可用鲎试剂方法进行细菌内毒素检测.

  8. Analysis of BDS Applications to Carry out Conformity Assessment%北斗卫星导航系统应用产品开展合格评定工作的思考

    Institute of Scientific and Technical Information of China (English)

    许冬彦; 马丽娜; 王维嘉

    2015-01-01

    As well as BeiDou navigation satellite system (BDS)begin to provide Full operational Service for China and its surrounding areas formally by the end of 2012,the government also gave out policies about BDS applications,and the industry and regional application demonstration propel steadily,BDS ushers a major historical opportunity of “large-scale,community, industrialization and internationalization”.Application products based on the BDS start to put into the mass market,there are so many types of manufacturers and products but lack of brand trust,so the consumers have difficult to choose from these products,these will impede the development of BDS products in domestic and international markets.Carry out conformity as-sessment of BDS applications products will help to improve the law-abiding awareness of market players,build market order of fair competition,ensure the quality and safety of various goods and service in the market,protect consumer,guide the orderly development of the market,and promote international trade and BDS industry developed health and sustainable.In this paper, we researched the significance of BDS conformity assessment,studied needs analysis as well as domestic and overseas status of BDS conformity assessment,put forward some proposal about working mechanism to carry out conformity assessment of BDS, hoping to play a role as reference to carry out conformity assessment work of products of satellite applications.%随着北斗卫星导航系统2012年底正式提供运行服务,国家对北斗系统应用政策出台,北斗系统导航行业和区域示范应用稳步推进,北斗系统导航迎来“规模化、社会化、产业化、国际化”的重大历史机遇。合格评定作为证明执行法律和贯彻标准的一个有力手段,世界发达国家非常重视推行合格评定工作,普遍实行了产品认证及市场准入制度。开展北斗系统应用产品的合格评定有利于提高市场主体的守法意

  9. Bacterial Ecology

    DEFF Research Database (Denmark)

    Fenchel, Tom

    2011-01-01

    Bacterial ecology is concerned with the interactions between bacteria and their biological and nonbiological environments and with the role of bacteria in biogeochemical element cycling. Many fundamental properties of bacteria are consequences of their small size. Thus, they can efficiently exploit...... biogeochemical processes are carried exclusively by bacteria. * Bacteria play an important role in all types of habitats including some that cannot support eukaryotic life....

  10. Biological Threats Detection Technologies

    International Nuclear Information System (INIS)

    Among many decisive factors, which can have the influence on the possibility of decreases the results of use biological agents should be mentioned obligatory: rapid detection and identification of biological factor used, the proper preventive treatment and the medical management. The aims of identification: to identify the factor used, to estimate the area of contamination, to evaluate the possible countermeasure efforts (antibiotics, disinfectants) and to assess the effectiveness of the decontamination efforts (decontamination of the persons, equipment, buildings, environment etc.). The objects of identification are: bacteria and bacteria's spores, viruses, toxins and genetically modified factors. The present technologies are divided into: based on PCR techniques (ABI PRISM, APSIS, BIOVERIS, RAPID), immuno (BADD, RAMP, SMART) PCR and immuno techniques (APDS, LUMINEX) and others (BDS2, LUNASCAN, MALDI). The selected technologies assigned to field conditions, mobile and stationary laboratories will be presented.(author)

  11. [Bacterial vaginosis].

    Science.gov (United States)

    Romero Herrero, Daniel; Andreu Domingo, Antonia

    2016-07-01

    Bacterial vaginosis (BV) is the main cause of vaginal dysbacteriosis in the women during the reproductive age. It is an entity in which many studies have focused for years and which is still open for discussion topics. This is due to the diversity of microorganisms that cause it and therefore, its difficult treatment. Bacterial vaginosis is probably the result of vaginal colonization by complex bacterial communities, many of them non-cultivable and with interdependent metabolism where anaerobic populations most likely play an important role in its pathogenesis. The main symptoms are an increase of vaginal discharge and the unpleasant smell of it. It can lead to serious consequences for women, such as an increased risk of contracting sexually transmitted infections including human immunodeficiency virus and upper genital tract and pregnancy complications. Gram stain is the gold standard for microbiological diagnosis of BV, but can also be diagnosed using the Amsel clinical criteria. It should not be considered a sexually transmitted disease but it is highly related to sex. Recurrence is the main problem of medical treatment. Apart from BV, there are other dysbacteriosis less characterized like aerobic vaginitis of which further studies are coming slowly but are achieving more attention and consensus among specialists. PMID:27474242

  12. The diagnostic value of CRP, IL-8, PCT, and sTREM-1 in the detection of bacterial infections in pediatric oncology patients with febrile neutropenia

    NARCIS (Netherlands)

    Miedema, Karin G. E.; de Bont, Eveline S. J. M.; Elferink, Rob F. M. Oude; van Vliet, Michel J.; Nijhuis, Claudi S. M. Oude; Kamps, Willem A.; Tissing, Wim J. E.

    2011-01-01

    In this study, we evaluated C-reactive protein (CRP), interleukin (IL)-8, procalcitonin (PCT), and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) as predictors for bacterial infection in febrile neutropenia, plus their usefulness in febrile neutropenia during chemotherapy-induced

  13. 多项目联合检测法在细菌性阴道病诊断中的应用%Application of multi-project joint detection method in the diagnosis of bacterial vaginosis

    Institute of Scientific and Technical Information of China (English)

    梅丽

    2013-01-01

      目的探讨多项目联合检测法在细菌性阴道病诊断中的应用。方法556例进行阴道分泌物检查患者,分别采用多项目联合检测法和Amsel法检测。结果多项目联合检测法阳性检测率(18.35%)高于Amsel法阳性检测率(12.05%),差异有统计学意义(P<0.01)。结论多项目联合检测法诊断妇科阴道疾病简便客观,适用于临床快速诊断细菌性阴道病。%Objective To discuss the application of multi-project joint detection method in the diagnosis of bacterial vaginosis. Methods 556 patients with vaginal discharge check were used multi-project joint detection method and Amsel detection method respectively. Results The positive detection rate of multi-project joint detection method(18.35%) was higher than that of Amsel detection method(12.05%),and the difference was significant(P<0.01). Conclusion Multi-project joint detection method is simple and objective in the diagnosis of gynecological vaginal diseases,and suitable for clinical rapid diagnosis of bacterial vaginosis.

  14. Comparison of a quantitative real-time polymerase chain reaction (qPCR) with conventional PCR, bacterial culture and ELISA for detection of Mycobacterium avium subsp. paratuberculosis infection in sheep showing pathology of Johne's disease.

    Science.gov (United States)

    Sonawane, Ganesh G; Tripathi, Bhupendra N

    2013-12-01

    A quantitative real-time PCR (qPCR) assay employing IS900 gene specific primers of Mycobacterium avium subsp. parartuberculosis (MAP) was compared with conventional PCR, bacterial culture and enzyme-linked immunosorbent assay in 38 sheep showing granulomatous enteritis and lymphadenitis with and without demonstration of acid-fast bacilli (AFB). The lesions were classified as multibacillary (MB) (n = 23), which had diffuse granulomatous lesions with abundant AFB, and paucibacillary (PB) (n = 15), which had focal or multifocal granulomatous lesions with few or no AFB. In the multibacillary group (MB), IS900 PCR detected 19 (82.6%), and qPCR detected all 23 (100%) sheep positive for MAP in the intestine and lymph node tissues. In the paucibacillary group (PB), IS900 PCR detected 2 (13.3%), and qPCR detected all 15 (100%) sheep positive for MAP in tissues. When results of both groups were taken together, IS900 PCR detected 21(55.2%), and qPCR detected all 38 (100%) animals positive for MAP genome either in the intestine or lymph node tissues. On Herrold egg yolk medium, tissues of 14 (60.9%) MB and 5 (33.3%) PB sheep were found to be positive for MAP. Out of 27 sheep (PB = 8, MB = 19) tested by an ELISA, 21 (77.7%) were found to be positive for MAP antibody, of which 25% (2/8) and 100% (19/19) sheep were from PB and MB sheep, respectively. Based on the results of the present study, it was concluded that qPCR was a highly sensitive test in comparison to conventional PCR, ELISA and bacterial culture for the diagnosis of paratuberculosis on infected tissues especially from paucibacillary sheep.

  15. BDS thin film damage competition

    Energy Technology Data Exchange (ETDEWEB)

    Stolz, C J; Thomas, M D; Griffin, A J

    2008-10-24

    A laser damage competition was held at the 2008 Boulder Damage Symposium in order to determine the current status of thin film laser resistance within the private, academic, and government sectors. This damage competition allows a direct comparison of the current state-of-the-art of high laser resistance coatings since they are all tested using the same damage test setup and the same protocol. A normal incidence high reflector multilayer coating was selected at a wavelength of 1064 nm. The substrates were provided by the submitters. A double blind test assured sample and submitter anonymity so only a summary of the results are presented here. In addition to the laser resistance results, details of deposition processes, coating materials, and layer count will also be shared.

  16. Molecular Analysis of Bacterial Communities and Detection of Potential Pathogens in a Recirculating Aquaculture System for Scophthalmus maximus and Solea senegalensis

    OpenAIRE

    Patrícia Martins; Cleary, Daniel F. R.; Pires, Ana C. C.; Ana Maria Rodrigues; Victor Quintino; Ricardo Calado; Gomes, Newton C M

    2013-01-01

    The present study combined a DGGE and barcoded 16S rRNA pyrosequencing approach to assess bacterial composition in the water of a recirculating aquaculture system (RAS) with a shallow raceway system (SRS) for turbot (Scophthalmus maximus) and sole (Solea senegalensis). Barcoded pyrosequencing results were also used to determine the potential pathogen load in the RAS studied. Samples were collected from the water supply pipeline (Sup), fish production tanks (Pro), sedimentation filter (Sed), b...

  17. Bacterial Hydrodynamics

    Science.gov (United States)

    Lauga, Eric

    2016-01-01

    Bacteria predate plants and animals by billions of years. Today, they are the world's smallest cells, yet they represent the bulk of the world's biomass and the main reservoir of nutrients for higher organisms. Most bacteria can move on their own, and the majority of motile bacteria are able to swim in viscous fluids using slender helical appendages called flagella. Low-Reynolds number hydrodynamics is at the heart of the ability of flagella to generate propulsion at the micrometer scale. In fact, fluid dynamic forces impact many aspects of bacteriology, ranging from the ability of cells to reorient and search their surroundings to their interactions within mechanically and chemically complex environments. Using hydrodynamics as an organizing framework, I review the biomechanics of bacterial motility and look ahead to future challenges.

  18. Bacterial hydrodynamics

    CERN Document Server

    Lauga, Eric

    2015-01-01

    Bacteria predate plants and animals by billions of years. Today, they are the world's smallest cells yet they represent the bulk of the world's biomass, and the main reservoir of nutrients for higher organisms. Most bacteria can move on their own, and the majority of motile bacteria are able to swim in viscous fluids using slender helical appendages called flagella. Low-Reynolds-number hydrodynamics is at the heart of the ability of flagella to generate propulsion at the micron scale. In fact, fluid dynamic forces impact many aspects of bacteriology, ranging from the ability of cells to reorient and search their surroundings to their interactions within mechanically and chemically-complex environments. Using hydrodynamics as an organizing framework, we review the biomechanics of bacterial motility and look ahead to future challenges.

  19. 细菌性阴道病联合测定技术在BV诊断中的应用%Application of bacterial vaginosis detection technology on diagnosing BV

    Institute of Scientific and Technical Information of China (English)

    张红; 黄艳英

    2012-01-01

    目的 探讨生化法在细菌性阴道病(BV)诊断中的应用价值.方法 分别使用镜检法和生化法对1466例就诊者的阴道分泌物进行检测.结果 在1 466例受检者中,使用生化法检出BV患者1 297例,使用镜检法检出BV患者1 301例.经统计学分析,二者检出BV的阳性率差异无统计学意义(x2=0.46,P>0.05),且二者的符合率为97.14% (1424/1466).结论 生化法检测准确快速,适宜在基层医院推广使用.%Objective To investigate the value of biochemical method in diagnosis of bacterial vaginosis. Methods Vaginal discharges from 1,466 women with suspected bacterial vaginosis were tested by using biochemical test and microscope test. Results In the 1,466 women, 1,297 women were detected as having bacterial vaginosis by using biochemical test, while 1 ,301 obtained a positive results by microscope test. There was no statistical significance (x2 - 0. 46 ,P > 0. 05 ) in the positive rates of bacterial vaginosis by these two methods. The coincidence rate of the two methods was 97. 14% (1424/1466). Conclusion Biochemical test was rapid and accurate compared with microscope test, which was of high value for use in township hospitals.

  20. Bacterial diseases

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    2005156 The study of bacteriophage-bases assay detecting ethambutol resistance in clinical isolates of Mycobacterium tuberculosis. MA Xiao-wei(马晓薇) ,et al. Pneum Hosp Shanghai,Shanghai 200433. Chin J Infect Dis,2004;22(6) :377-380. Objective: To set up and evaluate the method of phage amplified biologically assay (PhaB) in the rapid detection of ethambutol resistance. Methods:

  1. Advancement in the research of early detection of bacterial nucleic acid in molecular diagnosis of sepsis%脓毒症早期细菌核酸分子诊断研究进展

    Institute of Scientific and Technical Information of China (English)

    刘潇; 任辉; 彭代智

    2013-01-01

    Early diagnosis of sepsis helps make effective clinical decisions and improve the survival rate of patients with severe infection.However,the timely and accurate diagnosis of sepsis is still a great challenge in clinic.In order to settle the very problem,the scientists in the world have made a lot of ex ploration and research in the field of rapid molecular identification of pathogens.Nowadays,the nucleic acid detection of sepsis is mainly composed of 3 types of methodological strategies,either based on positive blood culture,single colonies,or directly on blood specimens.This paper presents a comprehensive overview of advances in the research of early detection of bacterial nucleic acid as molecular diagnosis of sepsis.

  2. Stable Carbon Isotope Fractionation during Bacterial Acetylene Fermentation: Potential for Life Detection in Hydrocarbon-Rich Volatiles of Icy Planet(oid)s

    OpenAIRE

    Miller, Laurence G.; Baesman, Shaun M.; Oremland, Ronald S.

    2015-01-01

    Abstract We report the first study of stable carbon isotope fractionation during microbial fermentation of acetylene (C2H2) in sediments, sediment enrichments, and bacterial cultures. Kinetic isotope effects (KIEs) averaged 3.7 ± 0.5‰ for slurries prepared with sediment collected at an intertidal mudflat in San Francisco Bay and 2.7 ± 0.2‰ for a pure culture of Pelobacter sp. isolated from these sediments. A similar KIE of 1.8 ± 0.7‰ was obtained for methanogenic enrichments derived from sedi...

  3. Identification of pathotypes of Xanthomonas axonopodis pv. manihotis in Africa and detection of quantitative trait loci and markers for resistance to bacterial blight of Cassava

    OpenAIRE

    Wydra, Kerstin; Zinsou, Valerien; Jorge, Véronique; Verdier, Valérie

    2004-01-01

    Cassava suffers from bacterial blight attack in all growing regions. Control by resistance is unstable due to high genotype–environment interactions. Identifying genes for resistance to African strains of Xanthomonas axonopodis pv. manihotis can support breeding efforts. Five F1 cassava genotypes deriving from the male parent ‘CM2177-2’ and the female parent ‘TMS30572’ were used to produce 111 individuals by backcrossing to the female parent. In all, 16 genotypes among the mapping population ...

  4. A Program Against Bacterial Bioterrorism

    DEFF Research Database (Denmark)

    Kemp, Michael; Dargis, Rimtas; Andresen, Keld;

    2012-01-01

    In 2002 it was decided to establish laboratory facilities in Denmark for diagnosing agents associated with bioterrorism in order to make an immediate appropriate response to the release of such agents possible. Molecular assays for detection of specific agents and molecular and proteomic techniques...... for bacterial infections not associated with bioterrorism that are difficult to culture or identify....

  5. Bacterial disease

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    2010289 The detection of marOR mutations and their relations with acrAB-tolC expression in Shigella. REN Jingchao(任静朝),et al. Dept Epidemiol & Biostatistics,Public Health Coll,Zhengzhou Univ,Zhengzhou 450001.Chin J Microbiol 2010;30(3):201-204. Objective To

  6. Clavibacter michiganensis subsp. michiganensis, Bacterial Canker of Tomato: 2. Comparison of the Effectiveness of Extraction Procedures and Sensitivity of Methods for Detection in Tomato Seeds

    Directory of Open Access Journals (Sweden)

    Svetlana Milijašević

    2007-01-01

    Full Text Available Two seed extraction procedures, used for detection of Clavibacter michiganensis subsp. michiganensis (Cmm in artifficially infested tomato seed lots, were evaluated. A comparison of the efficiency of pathogen detection by using different extraction methods showed that a grinding procedure was more effective than soaking seed samples. The extraction by grinding resulted in a higher number of samples with Cmm colonies than did the method that included soaking. The detection threshold of Cmm in relation to seed sample size wasevaluated by adding different numbers of artificially infested seeds to uninfected samples of 2000 or 5000 seeds. Four detection methods were simultaneously compared for their sensitivity in Cmm detection in seeds: isolation on semiselective media (mSCM, D2ANX, mCNS, direct PCR from seed material, Bio-PCR with initial culturing of bacteria on NBY agar prior to PCR, and Enrichment PCR. The pathogen was detected in samples of 2000 seeds containing one, five and ten infested seeds, in at least two out of three replicates by threedetection methods (selective plating, direct PCR and Bio-PCR, using the grinding extraction method with an addition of centrifugation step. In samples of 5000 seeds, five infested seeds were detected in all replicates by the same detection methods. Similar resultswere obtained by the soaking extraction method. In Enrichment PCR, positive results were obtained only in samples of 2000 seeds containing five and ten infested seeds regardless of the extraction method.

  7. Comparison of PCR,DIA and Pathogenicity Assay for Detection of Xanthomonas axonopodis pv.citri,the Causal Agent of Citrus Bacterial Canker Disease

    Institute of Scientific and Technical Information of China (English)

    WANG Zhong-kang; SUN Xian-yun; YIN You-ping; ZHOU Chang-yong; XIA Yu-xian

    2004-01-01

    Polymerase chain reaction (PCR) approach based on newly designed primers, JYF5/JYR5, was applied for specific detection of Xanthomonas axonopodis pv.citri(Xac). The efficiency and reliability of PCR method were compared with dot immunobinding assay (DIA) and classical pathogenicity test techniques for detecting suspensions of pure cells of Xac and soaking sap of citrus tissues. Detection sensitivity of PCR was about 4.5 cells or 1.56 pg target DNA per reaction which was higher than that of DIA (ca. 450 cells per dot).These three techniques (PCR assay, DIA and Pathogenecity test) could always detect Xac from symptomatic citrus samples. Different performances were obtained from citrus materials without symptoms, and the positive detection frequency was PCR, DIA and pathogenicity test.

  8. Design of GPS/BDS-based positioning and tracking system for moving targets%基于GPS/BDS的移动目标定位追踪系统设计

    Institute of Scientific and Technical Information of China (English)

    张超; 顾济华

    2015-01-01

    利用GPS(全球卫星定位系统)和BDS(北斗卫星导航系统)联合定位技术,设计了一款针对移动目标的高精度定位与跟踪系统.系统主要包括移动目标通信终端、GSM网络、GIS电子地图等.其中,核心部分——移动目标通信终端硬件由ATGM331C单元、TC35I单元和STC12C5A60S2微处理器单元等构成;其软件设计主要包括:微处理器初始化、GPS/BDS解码、短信命令解码和AT命令控制等.实践测试结果表明:该系统运行稳定,且移动目标通信终端具有定位精度高、体积小、功耗低、操作简单方便等特点,应用前景广阔.%By using the combined positioning technology of global positioning system(GPS)and BeiDou navigation satellite system(BDS),a high accuracy positioning and tracking system for moving targets was designed. The system consists of commu-nication terminal of moving target,GSM network and electronic map of GIS mainly. As the key part of the whole system,the hardware of the moving target communication terminal is composed of ATGM331C module,TC35I module and STC12C5A60S2 microprocessor. The software design includes microprocessor initialization,decoding of GPS/BDS navigation information,decoding of short message service commands and the AT command control mainly. The practical testing results indicate that the system can work steadily,and the moving target communication terminal has the characteristics of high accuracy positioning,small size,low power consumption and convenient operation. The system has a broad application prospect.

  9. 2006-2010年开平市细菌性食物中毒检测结果%Detection results of bacterial food poisoning in Kaiping City from 2006-2010

    Institute of Scientific and Technical Information of China (English)

    邓丽芳; 许立新; 王雪梅; 林崇昌

    2012-01-01

    [ Objective ] To study and analyze the current situation and epidemiological characteristics of bacterial food poisoning accidents in Kaiping City in the recent five years, provide a scientific basis for developing the preventive measures of food poisoning. [ Methods] The data and laboratory test results of bacterial food poisoning accidents from 2006-2010 were analyzed statistically. [Results]In the past five year, there were 19 bacterial food poisoning accidents in Kaiping City. The main pathogenic bacteria of bacterial food poisoning were Vibrio parahaemolyticus (36. 8% ) and Salmonella {31. 6% ). The peak season was the second quarter ( 36. 8% ) and the third quarter (57. 9% ). 36. 8% of accidents occurred in township restaurants ( 36. 8% } , followed by the urban restaurants {31.6% ) and the corporation canteens (21. 1% ). The detection rate of the anal swabs and feces samples was the highest (73.7% ) , followed by suspected leftovers (31.7% ) , and the detection rate of the vomitus was the lowest (16.7% ). The pathogen identification rate of accidents was 84. 2%. [ Conclusion] In the past five years, the main pathogenic bacteria of bacterial food poisoning accidents in Kaiping City are Vibrio parahaemolyticus and Salmonella. Moreover, the increasing temperature in summer and autumn is beneficial to the bacterial reproduction, and the health management in some restaurants is not standardized. Therefore, it is essential to strengthen the hygiene management and supervision in restaurants.%目的 探讨和分析近5年开平市发生细菌性食物中毒事故的情况及流行病学特征,为制定食物中毒防控措施提供科学依据.方法 依据2006-2010年细菌性食物中毒资料及实验室检测结果进行统计分析.结果 近5年开平市发生细菌性食物中毒事件19起.引起细菌性食物中毒病原菌主要是以副溶血性弧菌为主(36.8%),其次是沙门菌(31.6%),发生时间主要在第2、3季度(36.8%、57.9%);发

  10. Bacterial detection using a carbon nanotube gas sensor coupled with a microheater for ammonia synthesis by aerobic oxidisation of organic components.

    Science.gov (United States)

    Suehiro, J; Ikeda, N; Ohtsubo, A; Imasaka, K

    2009-06-01

    In this study, the authors propose a new bacteria detection method using a carbon nanotube (CNT) gas sensor and a microheater, which were coupled into a Bio-MEMS (microelectromechanical systems)-type device. Bacteria were heated by the microheater in air so that ammonia (NH(3)) gas can be generated by the oxidation reaction of organic components of bacteria. Thus generated NH(3) gas was detected by using the CNT gas sensor, which was fabricated by dielectrophoresis (DEP) and combined with the microheater to form a small chamber. Cyclic pulsed heating operation was employed so that the CNT response to elevated temperature did not mask NH(3) response. It was demonstrated that the proposed device could detect and quantify 10(7) bacteria cells (Escherichia coli). Possible application of DEP to trap and enrich target bacteria on the microheater was also discussed.

  11. Stable carbon isotope fractionation during bacterial acetylene fermentation: Potential for life detection in hydrocarbon-rich volatiles of icy planet(oid)s

    Science.gov (United States)

    Miller, Laurence; Baesman, Shaun; Oremland, Ron

    2015-01-01

    We report the first study of stable carbon isotope fractionation during microbial fermentation of acetylene (C2H2) in sediments, sediment enrichments, and bacterial cultures. Kinetic isotope effects (KIEs) averaged 3.7 ± 0.5‰ for slurries prepared with sediment collected at an intertidal mudflat in San Francisco Bay and 2.7 ± 0.2‰ for a pure culture of Pelobacter sp. isolated from these sediments. A similar KIE of 1.8 ± 0.7‰ was obtained for methanogenic enrichments derived from sediment collected at freshwater Searsville Lake, California. However, C2H2 uptake by a highly enriched mixed culture (strain SV7) obtained from Searsville Lake sediments resulted in a larger KIE of 9.0 ± 0.7‰. These are modest KIEs when compared with fractionation observed during oxidation of C1 compounds such as methane and methyl halides but are comparable to results obtained with other C2compounds. These observations may be useful in distinguishing biologically active processes operating at distant locales in the Solar System where C2H2 is present. These locales include the surface of Saturn's largest moon Titan and the vaporous water- and hydrocarbon-rich jets emanating from Enceladus.

  12. A bacterial community analysis using reverse transcription (RT) PCR which detects the bacteria with high activity in a wastewater treatment reactor

    Science.gov (United States)

    This research used reverse transcription polymerase chain reaction (RT-PCR) method to help detect active bacteria in a single-tank deammonification reactor combining partial nitritation and anammox. The single-tank aerobic deammonification reactor effectively removed the ammonia in anaerobically di...

  13. Rapid Ertapenem Susceptibility Testing and Klebsiella pneumoniae Carbapenemase Phenotype Detection in Klebsiella pneumoniae Isolates by Use of Automated Microscopy of Immobilized Live Bacterial Cells

    OpenAIRE

    Burnham, Carey-Ann D.; Frobel, Rachel A.; Herrera, Monica L.; Wickes, Brian L.

    2014-01-01

    We evaluated detection of ertapenem (ETP) resistance and Klebsiella pneumoniae carbapenemase (KPC) in 47 Klebsiella pneumoniae isolates using a novel automated microscopy system. Automated microscopy correctly classified 22/23 isolates as ETP resistant and 24/24 as ETP susceptible and correctly classified 21/21 isolates as KPC positive and 26/26 as KPC negative.

  14. Identification of Pathotypes of Xanthomonas axonopodis pv. manihotis in Africa and Detection of Quantitative Trait Loci and Markers for Resistance to Bacterial Blight of Cassava.

    Science.gov (United States)

    Wydra, K; Zinsou, V; Jorge, V; Verdier, V

    2004-10-01

    ABSTRACT Cassava suffers from bacterial blight attack in all growing regions. Control by resistance is unstable due to high genotype-environment interactions. Identifying genes for resistance to African strains of Xanthomonas axonopodis pv. manihotis can support breeding efforts. Five F(1) cassava genotypes deriving from the male parent 'CM2177-2' and the female parent 'TMS30572' were used to produce 111 individuals by backcrossing to the female parent. In all, 16 genotypes among the mapping population were resistant to stem inoculation by four strains of X. axonopodis pv. manihotis from different locations in Africa, and 19 groups with differential reactions to the four strains were identified, suggesting that the strains represent different pathotypes. Four genotypes were resistant to leaf inoculation, and three were resistant to both stem and leaf inoculations. Genotypes with susceptible, moderately resistant, and resistant reactions after leaf and stem inoculation partly differed in their reactions on leaves and stems. Based on the genetic map of cassava, single-markeranalysis of disease severity after stem-puncture inoculation was performed. Eleven markers were identified, explaining between 16 and 33.3% of phenotypic variance of area under disease progress curve. Five markers on three and one linkage groups from the female- and male-derived framework of family CM8820, respectively, seem to be weakly associated with resistance to four strains of X. axonopodis pv. manihotis. Based on the segregation of alleles from the female of family CM8873, one marker was significantly associated with resistance to two X. axonopodis pv. manihotis strains, GSPB2506 and GSPB2511, whereas five markers were not linked to any linkage group. The quantitative trait loci (QTL) mapping results also suggest that the four African strains belong to four different pathotypes. The identified pathotypes should be useful for screening for resistance, and the QTL and markers will support

  15. Phage amplification assay as rapid method for Salmonella detection Amplificação de bacteriófagos como um método rápido de detecção de Salmonella

    Directory of Open Access Journals (Sweden)

    Regina Silva de Siqueira

    2003-11-01

    Full Text Available The application of rapid methods is crucial for the HACCP program implantation in food industry. In this context, Phage Amplification Assay is a good candidate because is based on the interactions of phage and their host bacteria. This method using phage P22 was applied with to detect Salmonella cells in chicken breast. Samples of 25 g of chicken breast were diluted and the appropriate dilutions were used in phage amplification assay for Salmonella detection. After 3-4 h of incubation, it was observed a phage titre of approximately 10(4 pfu mL-1, indicating that there were Salmonella cells which were naturally present in the meat. The presence of Salmonella cells were verified by using direct plating on XLD agar and by conventional enrichment procedure. The colonies suspected to be Salmonella were serologically tested and were identified as belonging to the serogroups B (S. typhimurium group and D (S. enteritidis group. It can be concluded that this method provides a rapid and alternative application for Salmonella detection in food samples reducing both time and laboratory work to 3-4 hours.A aplicação de métodos rápidos é crucial para a implantação de programas de HACCP em indústrias de alimentos. Neste contexto, o método de amplificação de bacteriófagos é um instrumento de diagnóstico importante porque está baseado na interação dos bacteriófagos com suas células hospedeiras. Este método, usando o bacteriófago P22, foi aplicado para detectar Salmonella em peito de frango. Amostras de 25 g de peito de frango foram diluídas e as diluições apropriadas foram usadas no método de amplificação de bacteriófagos na detecção de Salmonella. Após 3-4 horas de incubação, foi observado uma titulação de partículas virais de, aproximadamente, 10(4 ufp mL-1 (unidades formadoras de placas virais, indicando a presença de células de Salmonella na carne de frango. A comprovação da presença de Salmonella neste produto foi

  16. A versatile-deployable bacterial detection system for food and environmental safety based on LabTube-automated DNA purification, LabReader-integrated amplification, readout and analysis.

    Science.gov (United States)

    Hoehl, Melanie M; Bocholt, Eva Schulte; Kloke, Arne; Paust, Nils; von Stetten, Felix; Zengerle, Roland; Steigert, Juergen; Slocum, Alexander H

    2014-06-01

    Contamination of foods is a public health hazard that episodically causes thousands of deaths and sickens millions worldwide. To ensure food safety and quality, rapid, low-cost and easy-to-use detection methods are desirable. Here, the LabSystem is introduced for integrated, automated DNA purification, amplification and detection. It consists of a disposable, centrifugally driven DNA purification platform (LabTube) and a low-cost UV/vis-reader (LabReader). For demonstration of the LabSystem in the context of food safety, purification of Escherichia coli (non-pathogenic E. coli and pathogenic verotoxin-producing E. coli (VTEC)) in water and milk and the product-spoiler Alicyclobacillus acidoterrestris (A. acidoterrestris) in apple juice was integrated and optimized in the LabTube. Inside the LabReader, the purified DNA was amplified, readout and analyzed using both qualitative isothermal loop-mediated DNA amplification (LAMP) and quantitative real-time PCR. For the LAMP-LabSystem, the combined detection limits for purification and amplification of externally lysed VTEC and A. acidoterrestris are 10(2)-10(3) cell-equivalents. In the PCR-LabSystem for E. coli cells, the quantification limit is 10(2) cell-equivalents including LabTube-integrated lysis. The demonstrated LabSystem only requires a laboratory centrifuge (to operate the disposable, fully closed LabTube) and a low-cost LabReader for DNA amplification, readout and analysis. Compared with commercial DNA amplification devices, the LabReader improves sensitivity and specificity by the simultaneous readout of four wavelengths and the continuous readout during temperature cycling. The use of a detachable eluate tube as an interface affords semi-automation of the LabSystem, which does not require specialized training. It reduces the hands-on time from about 50 to 3 min with only two handling steps: sample input and transfer of the detachable detection tube.

  17. Evaluation of the NanoCHIP® Gastrointestinal Panel (GIP) Test for Simultaneous Detection of Parasitic and Bacterial Enteric Pathogens in Fecal Specimens.

    Science.gov (United States)

    Ken Dror, Shifra; Pavlotzky, Elsa; Barak, Mira

    2016-01-01

    Infectious gastroenteritis is a global health problem associated with high morbidity and mortality rates. Rapid and accurate diagnosis is crucial to allow appropriate and timely treatment. Current laboratory stool testing has a long turnaround time (TAT) and demands highly qualified personnel and multiple techniques. The need for high throughput and the number of possible enteric pathogens compels the implementation of a molecular approach which uses multiplex technology, without compromising performance requirements. In this work we evaluated the feasibility of the NanoCHIP® Gastrointestinal Panel (GIP) (Savyon Diagnostics, Ashdod, IL), a molecular microarray-based screening test, to be used in the routine workflow of our laboratory, a big outpatient microbiology laboratory. The NanoCHIP® GIP test provides simultaneous detection of nine major enteric bacteria and parasites: Campylobacter spp., Salmonella spp., Shigella spp., Giardia sp., Cryptosporidium spp., Entamoeba histolytica, Entamoeba dispar, Dientamoeba fragilis, and Blastocystis spp. The required high-throughput was obtained by the NanoCHIP® detection system together with the MagNA Pure 96 DNA purification system (Roche Diagnostics Ltd., Switzerland). This combined system has demonstrated a higher sensitivity and detection yield compared to the conventional methods in both, retrospective and prospective samples. The identification of multiple parasites and bacteria in a single test also enabled increased efficiency of detecting mixed infections, as well as reduced hands-on time and work load. In conclusion, the combination of these two automated systems is a proper response to the laboratory needs in terms of improving laboratory workflow, turn-around-time, minimizing human errors and can be efficiently integrated in the routine work of the laboratory. PMID:27447173

  18. Evaluation of the NanoCHIP® Gastrointestinal Panel (GIP Test for Simultaneous Detection of Parasitic and Bacterial Enteric Pathogens in Fecal Specimens.

    Directory of Open Access Journals (Sweden)

    Shifra Ken Dror

    Full Text Available Infectious gastroenteritis is a global health problem associated with high morbidity and mortality rates. Rapid and accurate diagnosis is crucial to allow appropriate and timely treatment. Current laboratory stool testing has a long turnaround time (TAT and demands highly qualified personnel and multiple techniques. The need for high throughput and the number of possible enteric pathogens compels the implementation of a molecular approach which uses multiplex technology, without compromising performance requirements. In this work we evaluated the feasibility of the NanoCHIP® Gastrointestinal Panel (GIP (Savyon Diagnostics, Ashdod, IL, a molecular microarray-based screening test, to be used in the routine workflow of our laboratory, a big outpatient microbiology laboratory. The NanoCHIP® GIP test provides simultaneous detection of nine major enteric bacteria and parasites: Campylobacter spp., Salmonella spp., Shigella spp., Giardia sp., Cryptosporidium spp., Entamoeba histolytica, Entamoeba dispar, Dientamoeba fragilis, and Blastocystis spp. The required high-throughput was obtained by the NanoCHIP® detection system together with the MagNA Pure 96 DNA purification system (Roche Diagnostics Ltd., Switzerland. This combined system has demonstrated a higher sensitivity and detection yield compared to the conventional methods in both, retrospective and prospective samples. The identification of multiple parasites and bacteria in a single test also enabled increased efficiency of detecting mixed infections, as well as reduced hands-on time and work load. In conclusion, the combination of these two automated systems is a proper response to the laboratory needs in terms of improving laboratory workflow, turn-around-time, minimizing human errors and can be efficiently integrated in the routine work of the laboratory.

  19. Evaluation of the NanoCHIP® Gastrointestinal Panel (GIP) Test for Simultaneous Detection of Parasitic and Bacterial Enteric Pathogens in Fecal Specimens

    Science.gov (United States)

    Ken Dror, Shifra; Pavlotzky, Elsa; Barak, Mira

    2016-01-01

    Infectious gastroenteritis is a global health problem associated with high morbidity and mortality rates. Rapid and accurate diagnosis is crucial to allow appropriate and timely treatment. Current laboratory stool testing has a long turnaround time (TAT) and demands highly qualified personnel and multiple techniques. The need for high throughput and the number of possible enteric pathogens compels the implementation of a molecular approach which uses multiplex technology, without compromising performance requirements. In this work we evaluated the feasibility of the NanoCHIP® Gastrointestinal Panel (GIP) (Savyon Diagnostics, Ashdod, IL), a molecular microarray-based screening test, to be used in the routine workflow of our laboratory, a big outpatient microbiology laboratory. The NanoCHIP® GIP test provides simultaneous detection of nine major enteric bacteria and parasites: Campylobacter spp., Salmonella spp., Shigella spp., Giardia sp., Cryptosporidium spp., Entamoeba histolytica, Entamoeba dispar, Dientamoeba fragilis, and Blastocystis spp. The required high-throughput was obtained by the NanoCHIP® detection system together with the MagNA Pure 96 DNA purification system (Roche Diagnostics Ltd., Switzerland). This combined system has demonstrated a higher sensitivity and detection yield compared to the conventional methods in both, retrospective and prospective samples. The identification of multiple parasites and bacteria in a single test also enabled increased efficiency of detecting mixed infections, as well as reduced hands-on time and work load. In conclusion, the combination of these two automated systems is a proper response to the laboratory needs in terms of improving laboratory workflow, turn-around-time, minimizing human errors and can be efficiently integrated in the routine work of the laboratory. PMID:27447173

  20. Screening for bacterial DNA in the hard tick Hyalomma marginatum (Ixodidae from Socotra Island (Yemen: detection of Francisella-like endosymbiont

    Directory of Open Access Journals (Sweden)

    M. Montagna

    2012-12-01

    Full Text Available Thirty-four adult ticks collected from livestock on Socotra Island (Yemen were identified as Hyalomma marginatum using traditional morphological characteristics. Morphological identification was confirmed for all the collected specimens using a molecular approach targeting a fragment of the mitochondrial gene 12S rRNA. All the specimens were examined for the presence of tick-borne pathogens and the tick endosymbiont Candidatus Midichloria mitochondrii using polymerase chain reaction. Three specimens out of the 34 analyzed tested positive to the presence of Francisella spp. leading to the first detection of these bacteria in H. marginatum on Socotra Island. The phylogenetic analyses conducted on a 660 bp fragment of the ribosomal gene 16S rRNA of Francisella spp. (including F. philomiragia as outgroup, the four subspecies of F. tularensis and the Francisella-like endosymbiont of ticks confirm that the newly detected Francisella strains cluster into the Francisella-like endosymbionts of ticks. Interestingly, the detected Francisella-like endosymbiont, shows a different genotype to that previously isolated from H. marginatum collected in Bulgaria. No specimen was positive for the presence of Rickettsia spp., Coxiella burnetii, Borrelia burgdorferi or M. mitochondrii.

  1. Direct Detection of Fe(II) in Extracellular Polymeric Substances (EPS) at the Mineral-Microbe Interface in Bacterial Pyrite Leaching.

    Science.gov (United States)

    Mitsunobu, Satoshi; Zhu, Ming; Takeichi, Yasuo; Ohigashi, Takuji; Suga, Hiroki; Jinno, Muneaki; Makita, Hiroko; Sakata, Masahiro; Ono, Kanta; Mase, Kazuhiko; Takahashi, Yoshio

    2016-03-26

    We herein investigated the mechanisms underlying the contact leaching process in pyrite bioleaching by Acidithiobacillus ferrooxidans using scanning transmission X-ray microscopy (STXM)-based C and Fe near edge X-ray absorption fine structure (NEXAFS) analyses. The C NEXAFS analysis directly showed that attached A. ferrooxidans produces polysaccharide-abundant extracellular polymeric substances (EPS) at the cell-pyrite interface. Furthermore, by combining the C and Fe NEXAFS results, we detected significant amounts of Fe(II), in addition to Fe(III), in the interfacial EPS at the cell-pyrite interface. A probable explanation for the Fe(II) in detected EPS is the leaching of Fe(II) from the pyrite. The detection of Fe(II) also indicates that Fe(III) resulting from pyrite oxidation may effectively function as an oxidizing agent for pyrite at the cell-pyrite interface. Thus, our results imply that a key role of Fe(III) in EPS, in addition to its previously described role in the electrostatic attachment of the cell to pyrite, is enhancing pyrite dissolution. PMID:26947441

  2. Direct Detection of Fe(II) in Extracellular Polymeric Substances (EPS) at the Mineral-Microbe Interface in Bacterial Pyrite Leaching.

    Science.gov (United States)

    Mitsunobu, Satoshi; Zhu, Ming; Takeichi, Yasuo; Ohigashi, Takuji; Suga, Hiroki; Jinno, Muneaki; Makita, Hiroko; Sakata, Masahiro; Ono, Kanta; Mase, Kazuhiko; Takahashi, Yoshio

    2016-01-01

    We herein investigated the mechanisms underlying the contact leaching process in pyrite bioleaching by Acidithiobacillus ferrooxidans using scanning transmission X-ray microscopy (STXM)-based C and Fe near edge X-ray absorption fine structure (NEXAFS) analyses. The C NEXAFS analysis directly showed that attached A. ferrooxidans produces polysaccharide-abundant extracellular polymeric substances (EPS) at the cell-pyrite interface. Furthermore, by combining the C and Fe NEXAFS results, we detected significant amounts of Fe(II), in addition to Fe(III), in the interfacial EPS at the cell-pyrite interface. A probable explanation for the Fe(II) in detected EPS is the leaching of Fe(II) from the pyrite. The detection of Fe(II) also indicates that Fe(III) resulting from pyrite oxidation may effectively function as an oxidizing agent for pyrite at the cell-pyrite interface. Thus, our results imply that a key role of Fe(III) in EPS, in addition to its previously described role in the electrostatic attachment of the cell to pyrite, is enhancing pyrite dissolution.

  3. Direct Detection of Fe(II) in Extracellular Polymeric Substances (EPS) at the Mineral-Microbe Interface in Bacterial Pyrite Leaching

    Science.gov (United States)

    Mitsunobu, Satoshi; Zhu, Ming; Takeichi, Yasuo; Ohigashi, Takuji; Suga, Hiroki; Jinno, Muneaki; Makita, Hiroko; Sakata, Masahiro; Ono, Kanta; Mase, Kazuhiko; Takahashi, Yoshio

    2016-01-01

    We herein investigated the mechanisms underlying the contact leaching process in pyrite bioleaching by Acidithiobacillus ferrooxidans using scanning transmission X-ray microscopy (STXM)-based C and Fe near edge X-ray absorption fine structure (NEXAFS) analyses. The C NEXAFS analysis directly showed that attached A. ferrooxidans produces polysaccharide-abundant extracellular polymeric substances (EPS) at the cell-pyrite interface. Furthermore, by combining the C and Fe NEXAFS results, we detected significant amounts of Fe(II), in addition to Fe(III), in the interfacial EPS at the cell-pyrite interface. A probable explanation for the Fe(II) in detected EPS is the leaching of Fe(II) from the pyrite. The detection of Fe(II) also indicates that Fe(III) resulting from pyrite oxidation may effectively function as an oxidizing agent for pyrite at the cell-pyrite interface. Thus, our results imply that a key role of Fe(III) in EPS, in addition to its previously described role in the electrostatic attachment of the cell to pyrite, is enhancing pyrite dissolution. PMID:26947441

  4. A New Alkaline pH-Adjusted Medium Enhances Detection of β-Hemolytic Streptococci by Minimizing Bacterial Interference Due to Streptococcus salivarius

    Science.gov (United States)

    Dierksen, Karen P.; Ragland, Nancy L.; Tagg, John R.

    2000-01-01

    A new selective medium (CNA-P) that reduces or eliminates the inhibitory activity of bacteriocin-producing Streptococcus salivarius against β-hemolytic streptococci has been developed and compared with sheep blood agar (SBA) for the sensitive detection of small numbers of β-hemolytic streptococci in clinical specimens. CNA-P has as its basis a commercial medium (Difco Columbia CNA agar) supplemented with 5% (vol/vol) sheep blood, and the CNA is further modified by addition of 100 mM PIPES buffer [piperazine-N,N′-bis(2-ethanesulfonic acid)] (pH 7.5) to maintain cultures at an alkaline pH during incubation. CNA-P was shown to inhibit the production and/or release of four different types of S. salivarius bacteriocins or bacteriocin-like inhibitory molecules. The efficacies of CNA-P and SBA for detection of β-hemolytic streptococci in 1,352 pharyngeal samples from 376 children were compared. The β-hemolytic streptococcal isolates recovered from the samples included 314 group A (S. pyogenes), 61 group G, 33 group B, and 5 group C streptococci. Of 314 samples that yielded S. pyogenes, 300 were positive on CNA-P (96%) and 264 (86%) were positive on SBA. A significantly greater number of S. pyogenes isolates from these samples were recovered only on CNA-P (50 of 314) compared with the number of isolates recovered only on SBA (14 of 314). In addition, the degree of positivity, a measure of the total numbers of S. pyogenes isolates on the plate, was significantly higher on CNA-P than on SBA (2.40 versus 2.07; P < 0.001). Interestingly, CNA-P was also found to enhance the hemolytic activity of streptolysin O, allowing detection of streptolysin S-deficient S. pyogenes strains which might otherwise go undetected on SBA and other isolation media. PMID:10655361

  5. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    Management of bacterial infections is becoming increasingly difficult due to the emergence and increasing prevalence of bacterial pathogens that are resistant to available antibiotics. Conventional antibiotics generally kill bacteria by interfering with vital cellular functions, an approach that ...

  6. Use of Blood Smears and Dried Blood Spots for Polymerase Chain Reaction-Based Detection and Quantification of Bacterial Infection and Plasmodium falciparum in Severely Ill Febrile African Children.

    Science.gov (United States)

    Wihokhoen, Benchawan; Dondorp, Arjen M; Turner, Paul; Woodrow, Charles J; Imwong, Mallika

    2016-02-01

    Molecular approaches offer a means of testing archived samples stored as dried blood spots in settings where standard blood cultures are not possible. Peripheral blood films are one suggested source of material, although the sensitivity of this approach has not been well defined. Thin blood smears and dried blood spots from a severe pediatric malaria study were assessed using specific polymerase chain reaction (PCR) primers to detect non-typhoidal Salmonella (NTS; MisL gene), Streptococcus pneumoniae (lytA), and Plasmodium falciparum (18S rRNA). Of 16 cases of NTS and S. pneumoniae confirmed on blood culture, none were positive by PCR using DNA extracts from blood films or dried blood spots. In contrast, four of 36 dried blood spots and two of 178 plasma samples were PCR positive for S. pneumoniae, despite negative bacterial blood cultures, suggesting false positives. Quantitative assessment revealed that the effective concentration of P. falciparum DNA in blood films was three log orders of magnitude lower than for dried blood spots. The P. falciparum kelch13 gene could not be amplified from blood films. These findings question the value of blood PCR-based approaches for detection of NTS and S. pneumoniae, and show that stored blood films are an inefficient method of studying P. falciparum.

  7. Rheumatoid arthritis and bacterial infections

    OpenAIRE

    N L Prokopjeva; N N Vesikova; I M Marusenko; V A Ryabkov

    2008-01-01

    To study features of bacterial infections course in pts with rheumatoid arthritis (RA) and changes of laboratory measures after focus of infection sanation. Material and methods. 46 pts with definite rheumatoid arthritis were examined at the time of comorbid infection (Cl) detection and after infection focus sanation. Bacteriological test with evaluation of flora sensitivity to antibiotics by disco-diffusion method was performed at baseline and after the course of antibacterial therapy to ass...

  8. Extraction of Bacterial RNA from Soil: Challenges and Solutions

    OpenAIRE

    Wang, Yong; Hayatsu, Masahito; Fujii, Takeshi

    2012-01-01

    Detection of bacterial gene expression in soil emerged in the early 1990s and provided information on bacterial responses in their original soil environments. As a key procedure in the detection, extraction of bacterial RNA from soil has attracted much interest, and many methods of soil RNA extraction have been reported in the past 20 years. In addition to various RT-PCR-based technologies, new technologies for gene expression analysis, such as microarrays and high-throughput sequencing techn...

  9. Multiplex isothermal solid-phase recombinase polymerase amplification for the specific and fast DNA-based detection of three bacterial pathogens

    International Nuclear Information System (INIS)

    We report on the development of an on-chip RPA (recombinase polymerase amplification) with simultaneous multiplex isothermal amplification and detection on a solid surface. The isothermal RPA was applied to amplify specific target sequences from the pathogens Neisseria gonorrhoeae, Salmonella enterica and methicillin-resistant Staphylococcus aureus (MRSA) using genomic DNA. Additionally, a positive plasmid control was established as an internal control. The four targets were amplified simultaneously in a quadruplex reaction. The amplicon is labeled during on-chip RPA by reverse oligonucleotide primers coupled to a fluorophore. Both amplification and spatially resolved signal generation take place on immobilized forward primers bount to expoxy-silanized glass surfaces in a pump-driven hybridization chamber. The combination of microarray technology and sensitive isothermal nucleic acid amplification at 38 °C allows for a multiparameter analysis on a rather small area. The on-chip RPA was characterized in terms of reaction time, sensitivity and inhibitory conditions. A successful enzymatic reaction is completed in <20 min and results in detection limits of 10 colony-forming units for methicillin-resistant Staphylococcus aureus and Salmonella enterica and 100 colony-forming units for Neisseria gonorrhoeae. The results show this method to be useful with respect to point-of-care testing and to enable simplified and miniaturized nucleic acid-based diagnostics. (author)

  10. Establishment and Application of Multiplex PCR Assay for Detection of Five Freshwater Bacterial Species%5 种淡水细菌的多重 PC R 检测方法的建立及其应用

    Institute of Scientific and Technical Information of China (English)

    艾克特; 徐佩; 周静文; 万晶; 杨代勤; 许巧情

    2015-01-01

    Detection of bacteria with traditional method of microscope examination leads to high inaccuracy .On the contrary , the PCR method is specific and accurate to identify bacterial species . A multiplex PCR method for accurate detection of conventional bacteria in aquatic animals was developed and used to amplify Hly A gene in Aeromonas hydrophila ,Khe gene in Klebsiella pneumoniae ,Sip gene in Streptococcus agalactiae ,Ser C gene ,Eip gene in Edwardsiella ictaluri ,and Muk F gene ,and Gad B gene in Edwardsiella tarda .The results showed that the amplification was found to be high specificity .A double PCR method for simultaneous detection of S . agalactiae and E .ictalur and a multiplex PCR method for simultaneous detection of A . hydrophila , K . pneumoniae , E . tarda and E .ictalur were developed .In order to verify the accuracy of the multiplex PCR method , the diseased ricefield eel (Monopterus albus)were collected for isolation and culture of bacteria ,as well as for DNA extraction from the cultured bacteria .K .pneumoniae and A .hydrophila were detected by multiplex PCR method .And the established multiplex PCR had important significance for rapid detection of aquatic bacterial conventional pathogenic bacterium and molecular epidemiological research .%细菌对水产养殖品种危害大 ,造成的经济损失高.传统的显微镜镜检方法检测细菌误差大 ,而利用PCR方法鉴定细菌种类特异性强 ,准确性高.利用多重PCR探索出一种能准确鉴定水产常见细菌.研究表明 ,利用PCR分别扩增了嗜水气单胞菌 Hly A基因 ,肺炎克雷伯菌Khe基因 ,无乳链球菌Sip基因 ,(鱼回)爱德华氏菌Ser C基因和Eip基因以及迟钝爱德华氏菌M uk F基因和Gad B基因 ,扩增特异性强.并成功地建立了一种同时用于无乳链球菌和(鱼回)爱德华氏菌等两种细菌以及(鱼回)爱德华氏菌、肺炎克雷伯菌、迟钝爱德华氏菌和嗜水气单胞菌等4种细菌的多重 PCR检测方法.为

  11. 细菌性阴道病40例不同检测方法结果比较%Compared the results of different methods for detecting in 40 patients with bacterial vaginosis

    Institute of Scientific and Technical Information of China (English)

    张香波

    2014-01-01

    Objective:To investigate the 3 methods of direct smear staining,isolation and cultivation of bacteria,BV test in the diagnosis of bacterial vaginosis and clinical significance.Methods:600 suspected cases of patients with bacterial vaginosis were treated from March 2012 to February 2014.All cases were collected the vagina secretion,which was tested throuth bacterial culture,smear Gram staining microscopic examination of clue cell and BV test.Results:In 600 cases of suspected patients, 136 cases were diagnosed by the gold standard test method.Direct smear staining detected 66 cases(48.5%).Isolation and cultivation of bacteria were detected in 30 cases(22.1%).The BV test detected 40 cases(29.4%).The positive rate of 3 methods had no significant difference(P>0.05).Conclusion:Direct smear staining method is simple and fast,as the preferred method of screening.Isolation and culture of bacteria is with high accuracy,but culture positive rate is low.The BV test is a rapid and sensitive method of operation,simple and easy to operate.Every method has the advantages of each clinical department.We should select the different method ccording to specific situation.%目的:探讨直接涂片染色、细菌分离培养、BV试验3种方法对诊断细菌性阴道病的临床意义。方法:2012年3月-2014年2月收治怀疑为细菌性阴道病患者600例,均进行采集阴道后穹隆分泌物,做细菌培养、涂片革兰染色镜检线索细胞和BV试验。结果:本组600例疑似患者,经过金标检验方法确诊136例,其中直接涂片染色检出66例(48.5%),细菌分离培养检出30例(22.1%),BV 试验检检出40例(29.4%),3种方法阳性检出率差异无统计学意义(P>0.05)。结论:直接涂片染色法简便、快捷,可以作为筛查的首选方法。细菌分离培养准确率高,但是培养阳性率低。BV试验是一种快速敏感、简便易操作的操作方法。各方法具有各自的优点,临床要根据具体

  12. 应用荧光定量PCR检测细菌性脑膜炎病原体DNA的研究%Studies using fluorescence quantitative PCR to detect DNA of pathogens responsible for bacterial meningitis pathogen

    Institute of Scientific and Technical Information of China (English)

    杨红梅; 吕静; 邹文菁; 徐军强; 占建波; 江永忠; 朱兵清

    2012-01-01

    目的 应用荧光定量PCR检测细菌性脑膜炎病原体DNA,并对脑膜炎奈瑟菌进行基因分群. 方法 提取脑膜炎患者脑脊液和血标本中待检菌DNA,采用荧光定量PCR扩增ctrA、bexA、lytA基因,对ctrA扩增阳性标本及部分流脑菌株进行基因分群. 结果 685份脑脊液标本中19份检出脑膜炎奈瑟菌、8份检出肺炎链球菌、2份检出b型流感嗜血杆菌DNA基因片段;2份血清标本脑膜炎奈瑟菌DNA基因检测均为阳性.对ctrA基因扩增阳性标本进行A、B、C、W135、X及Y分群,有18份为C群,3份为B群;部分健康人群携带的流脑菌株有14份为B群,2份为C群,1份为X群. 结论 荧光定量PCR灵敏性高,检测快速,可用于细菌性脑膜炎病原体的检测、鉴别及对脑膜炎奈瑟菌的分群.%Objectives To use real-time fluorescence quantitative PCR to detect the pathogens responsible for bacterial meningitis and to identify the serogroups of Neisseria rneningitidis. Methods Bacterial DNA was extracted from 685 samples of cerebral spinal fluid (CSF) and 2 blood samples. Species-specific genes {ctrA for N. meningitidis, bex A for Haemophilus influenzae , and lytA for Streptococcus pneumoniae} were detected from the extracted DNA with real-time PCR, and ctrA-positive specimens were serogrouped. Results Of the 685 CSF samples, 19 were positive for ctrA,, 8 were positive for lytA, and 2 were positive for hex A. Both of the two blood samples were positive for ctrA. Of the 21 samples positive for ctrA,18 were serogroup C and 3 were serogroup B. Of the 17 N. rneningitidis strains isolated from healthy carriers, 14 were serogroup B, 2 were serogroup C, and lwas serogroup X. Conclusion Real-time PCR was sensitive and rapid. This method can be used to detect pathogens in clinical specimens of bacterial meningitis and identify the serogroup of N. meningitides.

  13. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    that imposes selection pressure for resistant bacteria. New approaches are urgently needed. Targeting bacterial virulence functions directly is an attractive alternative. An obvious target is bacterial adhesion. Bacterial adhesion to surfaces is the first step in colonization, invasion, and biofilm formation....... As such, adhesion represents the Achilles heel of crucial pathogenic functions. It follows that interference with adhesion can reduce bacterial virulence. Here, we illustrate this important topic with examples of techniques being developed that can inhibit bacterial adhesion. Some of these will become...

  14. Evaluation of the limulus amoebocyte lysate test in conjunction with a gram negative bacterial plate count for detecting irradiation of chicken

    Science.gov (United States)

    Scotter, Susan L.; Wood, Roger; McWeeny, David J.

    A study to evaluate the potential of the Limulus amoebocyte lysate (LAL) test in conjuction with a Gram negative bacteria (GNB) plate count for detecting the irradiation of chicken is described. Preliminary studies demonstrated that chickens irradiated at an absorbed dose of 2.5 kGy could be differentiated from unirradiated birds by measuring levels of endotoxin and of numbers of GNB on chicken skin. Irradiated birds were found to have endotoxin levels similar to those found in unirradiated birds but significantly lower numbers of GNB. In a limited study the test was found to be applicable to birds from different processors. The effect of temperature abuse on the microbiological profile, and thus the efficacy of the test, was also investigated. After temperature abuse, the irradiated birds were identifiable at worst up to 3 days after irradiation treatment at the 2.5 kGy level and at best some 13 days after irradiation. Temperature abuse at 15°C resulted in rapid recovery of surviving micro-organisms which made differentiation of irradiated and unirradiated birds using this test unreliable. The microbiological quality of the bird prior to irradiation treatment also affected the test as large numbers of GNB present on the bird prior to irradiation treatment resulted in larger numbers of survivors. In addition, monitoring the developing flora after irradiation treatment and during subsequent chilled storage also aided differentiation of irradiated and unirradiated birds. Large numbers of yeasts and Gram positive cocci were isolated from irradiated carcasses whereas Gram negative oxidative rods were the predominant spoilage flora on unirradiated birds.

  15. A Single-Tube, Functional Marker-Based Multiplex PCR Assay for Simultaneous Detection of Major Bacterial Blight Resistance GenesXa21, xa13 andxa5 in Rice

    Institute of Scientific and Technical Information of China (English)

    S. K. HAJIRA; M. ANILA; S. BHASKAR; V. ABHILASH; H. K. MAHADEVASWAMY; M. KOUSIK; T. DILIPKUMAR; G. HARIKA; G. REKHA; R. M. SUNDARAM; G. S. LAHA; A. YUGANDER; S. M. BALACHANDRAN; B. C. VIRAKTAMATH; K. SUJATHA; C. H. BALACHIRANJEEVI; K. PRANATHI

    2016-01-01

    In marker-assisted breeding for bacterial blight (BB) resistance in rice, three major resistance genes, viz.,Xa21, xa13andxa5,are routinely deployed either singly or in combinations. As efficient and functional markers are yet to be developed forxa13 andxa5,we have developed simple PCR-based functional markers for both the genes.Forxa13,we designed a functional PCR-based marker, xa13-prom targeting the InDel polymorphism in the promoter of candidate geneOs8N3 located on chromosome 8 of rice. With respect toxa5, a multiplex-PCR based functional marker system, named xa5FM, consisting of two sets of primer pairs targeting the 2-bp functional nucleotide polymorphism in the exon II of the geneTFIIAɤ5 (candidate forxa5), has been developed. Both xa13-prom and xa5FM can differentiate the resistant and susceptible alleles forxa13 andxa5, respectively, in a co-dominant fashion. Using these two functional markers along with the already reported functional PCR-based marker forXa21 (pTA248),we designed a single-tube multiplex PCR based assay for simultaneous detection of all the three major resistance genes and demonstrated the utility of the multiplex marker system in a segregating population.

  16. Bacterial microleakage of aged adhesive restorations

    Directory of Open Access Journals (Sweden)

    Nevin Cobanoglu

    2015-01-01

    Full Text Available Objective: The aim of this study was to investigate the marginal bacterial leakage of two self-etch adhesive systems after long-term water storage. Materials and Methods: Class V cavities were prepared on the buccal and lingual surfaces of extracted premolar teeth. After the sterilization of the teeth, four cavities were not restored for control purposes, whereas the other teeth were divided into two groups (n = 16 cavities each: Clearfil Protect Bond (CPB, Clearfil SE Bond (CSE. After the application of the bonding agent, cavities were restored with a composite resin. Then, the teeth were thermo cycled, stored in saline solution for 6 months and put into a broth culture of Streptococcus mutans. The teeth were fixed, sectioned and stained using the Gram-Colour modified method. The stained sections were then evaluated under a light microscope. The bacterial leakage was scored as: 0 - absence of stained bacteria, 1 - bacterial staining along the cavity walls, 2 - bacterial staining within the cut dentinal tubules. The data were analysed using the Kruskal-Wallis and Mann-Whitney U-test (P = 0.05. Results: The bacterial staining was detected within the cut dentinal tubules in all control cavities, in three cavities in the CSE group and one cavity in the CPB group. There were no observed statistically significant differences between the bacterial penetrations of the two bonding systems (P > 0.05. Conclusion: Both bonding systems provided acceptable prevention of marginal bacterial leakage after long-term water storage.

  17. 迟钝爱德华氏菌耐药表型及 4 种耐药基因检测%Detection of Drug Resistance and Four Drug Resistance Genes in Bacterial Pathogen Edwardsiella tarda

    Institute of Scientific and Technical Information of China (English)

    葛慕湘; 靳晓敏; 张艳英; 房海; 陈翠珍

    2015-01-01

    The drug-resistance was tested by Kirby-Bauer method ,and four drug-resistant genes including TEM ,ant(3 )-Ⅰ ,Sul3 and tet(A) genes against β-lactamase genotypes ,aminoglycoside ,sulfonamides and tetracyclines were detected in 35 strains (five strains each case) selected from 130 strains isolated from seven cases of Japanese flounder Paralichthys oliv aceus infected by Edw ardsiella tarda by PCR method to investigate the correlation between the drug resistance phenotypes and the drug resistance genotypes in the bacterial pathogen .The results showed that all detected strains had TEM and ant (3 )-Ⅰgenes ,62 .9%(22/35) of the strains carrying Sul3 gene ,and no tet(A) gene was detected in the experiment .All strains were found to be multi-drug resistant ,most of which were resistant to 7—9 antibiotics .There was a close relationship between the drug-resistance phenotype and the related resistance genes ,without entirely cor-responding .%从7起牙鲆迟钝爱德华氏菌感染病例中分离到130株致病菌 ,每个病例挑选5株共计35株 ,用K-B纸片扩散法检测其耐药表型 ;用PCR方法检测b-内酰胺类 T EM 基因、氨基糖苷类ant (3)-Ⅰ基因、磺胺类Sul3基因和四环素类tet(A)基因 ,分析耐药基因与耐药表型间的关系 ,以查明牙鲆源致病性迟钝爱德华氏菌不同类型常见耐药基因的携带状况 ,探讨耐药基因与耐药表型之间的相关性.结果显示 ,所检的35株迟钝爱德华氏菌均携带 TEM 基因和ant(3)-Ⅰ基因 ,62 .9% (22 /35)携带Sul3基因 ,未检出tet (A )基因 ;所有菌株均具有多重耐药性 ,大部分菌株耐抗菌类药物达7~9种 ;耐药基因的携带与耐药表型间存在较密切的相关性 ,但并非完全对应.

  18. Vimentin in Bacterial Infections

    Directory of Open Access Journals (Sweden)

    Tim N. Mak

    2016-04-01

    Full Text Available Despite well-studied bacterial strategies to target actin to subvert the host cell cytoskeleton, thus promoting bacterial survival, replication, and dissemination, relatively little is known about the bacterial interaction with other components of the host cell cytoskeleton, including intermediate filaments (IFs. IFs have not only roles in maintaining the structural integrity of the cell, but they are also involved in many cellular processes including cell adhesion, immune signaling, and autophagy, processes that are important in the context of bacterial infections. Here, we summarize the knowledge about the role of IFs in bacterial infections, focusing on the type III IF protein vimentin. Recent studies have revealed the involvement of vimentin in host cell defenses, acting as ligand for several pattern recognition receptors of the innate immune system. Two main aspects of bacteria-vimentin interactions are presented in this review: the role of vimentin in pathogen-binding on the cell surface and subsequent bacterial invasion and the interaction of cytosolic vimentin and intracellular pathogens with regards to innate immune signaling. Mechanistic insight is presented involving distinct bacterial virulence factors that target vimentin to subvert its function in order to change the host cell fate in the course of a bacterial infection.

  19. Nest Material Shapes Eggs Bacterial Environment

    Science.gov (United States)

    Ruiz-Castellano, Cristina; Tomás, Gustavo; Ruiz-Rodríguez, Magdalena; Martín-Gálvez, David; Soler, Juan José

    2016-01-01

    Selective pressures imposed by pathogenic microorganisms to embryos have selected in hosts for a battery of antimicrobial lines of defenses that includes physical and chemical barriers. Due to the antimicrobial properties of volatile compounds of green plants and of chemicals of feather degrading bacteria, the use of aromatic plants and feathers for nest building has been suggested as one of these barriers. However, experimental evidence suggesting such effects is scarce in the literature. During two consecutive years, we explored experimentally the effects of these nest materials on loads of different groups of bacteria (mesophilic bacteria, Enterobacteriaceae, Staphylococcus and Enterococcus) of eggshells in nests of spotless starlings (Sturnus unicolor) at the beginning and at the end of the incubation period. This was also explored in artificial nests without incubation activity. We also experimentally increased bacterial density of eggs in natural and artificial nests and explored the effects of nest lining treatments on eggshell bacterial load. Support for the hypothetical antimicrobial function of nest materials was mainly detected for the year and location with larger average values of eggshell bacterial density. The beneficial effects of feathers and plants were more easily detected in artificial nests with no incubation activity, suggesting an active role of incubation against bacterial colonization of eggshells. Pigmented and unpigmented feathers reduced eggshell bacterial load in starling nests and artificial nest boxes. Results from artificial nests allowed us to discuss and discard alternative scenarios explaining the detected association, particularly those related to the possible sexual role of feathers and aromatic plants in starling nests. All these results considered together confirm the antimicrobial functionality mainly of feathers but also of plants used as nest materials, and highlight the importance of temporally and geographically

  20. Estimativa da incerteza em ensaio de detecção de endotoxina bacteriana pelo método de gelificação Estimation of uncertainty in the detection of bacterial endotoxin by gel-clot method

    Directory of Open Access Journals (Sweden)

    Felipe Rebello Lourenço

    2005-12-01

    Full Text Available Desde a publicação da ISO 17025:1999, o interesse em métodos para estimativa da incerteza em ensaios qualitativos, do tipo "passa/não passa", têm ganho grande importância. Uma forma de estimar e informar a incerteza deste tipo de ensaio é o uso das probabilidades de respostas-falsas, particularmente falsos-positivos e falsos-negativos, determinados a partir do teorema de Bayes. O objetivo deste artigo é estabelecer um método para a estimativa de incerteza em ensaios de detecção de endotoxina bacteriana pelo método in vitro Limulus Amebocyte Lysate (LAL. Considerando a confirmação da sensibilidade do LAL e a validação do teste, a probabilidade de uma resposta falsa corresponde à soma da probabilidade dos resultados falso-negativos e falso-positivos. A partir dos resultados obtidos foi verificado que a etapa da confirmação da sensibilidade do LAL contribui para a incerteza de forma mais significativa (67,6% que a etapa de validação do teste (32,4%. Através de um procedimento simples, descrito neste artigo, e de dados obtidos a partir da confirmação da sensibilidade do LAL e validação do teste para um produto em questão é possível obter uma estimativa de incerteza razoável para o ensaio de detecção de endotoxinas bacterianas pelo método de gelificação.Since the publication of ISO 17025:1999, the interest in methods for estimation of the uncertainty in qualitative analysis, such as 'pass/fail', have became more important. The usual form of estimating and informing the uncertainty in this kind of analysis is the use of false-response rates, particularly false-positive and false-negative, determinated from Bayes theorem. The aim of this paper is establish a method for estimation of the uncertainty in the detection of bacterial endotoxins by in vitro Limulus Amebocyte Lysate (LAL test. Considering the confirmation of LAL sensitivity and the validation of the test, the probability of a false-response corresponds to the

  1. The problem of bacterial diarrhoea.

    Science.gov (United States)

    Harries, J T

    1976-01-01

    The reported incidence of "pathogenic" bacteria, as judged by serotype, in the stools of children with acute diarrhoea has varied from 4 to 33% over the last twenty years. Techniques such as tissue culture provide a means for detecting enterotoxin-producing strains of bacteria, strains which often do not possess "pathogenic" serotypes. "Pathogenicity" requires redefinition, and the aetiological importance of bacteria in diarrhoea is probably considerably greater than previous reports have indicated. Colonization of the bowel by a pathogen will result in structural and/or mucosal abnormalities, and will depend on a series of complex interactions between the external environment, the pathogen, and the host and its resident bacterial flora. Enteropathogenic bacteria may be broadly classified as (i) invasive (e.g. Shigella, Salmonella and some Escherichia coli) which predominantly affect the distal bowel, or (ii) non-invasive (e.g. Vibrio cholerae and E. coli) which affect the proximal bowel. V. cholerae and E. coli elaborate heat-labile enterotoxins which activate adenylate cyclase and induce small intestinal secretion; the secretory effects of heat-stable E. coli and heat-labile Shigella dysenteriae enterotoxins are not accompanied by cyclase activation. The two major complications of acute diarrhoea are (i) hypernatraemic dehydration with its attendant neurological, renal and vascular lesions, and (ii) protracted diarrhoea which may lead to severe malnutrition. Deconjugation of bile salts and colonization of the small bowel with toxigenic strains of E. coli may be important in the pathophysiology of the protracted diarrhoea syndrome. The control of bacterial diarrhoea requires a corrdinated political, educational, social, public health and scientific attack. Bacterial diarrhoea is a major health problem throughout the world, and carries an appreciable morbidity and mortality. This is particularly the case during infancy, and in those developing parts of the world

  2. Detecção da resistência a antibióticos de bactérias isoladas de casos clínicos ocorridos em animais de companhia Detection of antibiotic resistance in clinical bacterial strains from pets

    Directory of Open Access Journals (Sweden)

    P. Poeta

    2008-04-01

    Full Text Available The identification of different bacterial strains and the occurrence of antibiotic resistance were investigated in several infection processes of pets as skin abscess with purulent discharge, bronco alveolar fluid, earwax, urine, mammary, and eye fluid. Streptococcus spp. and Staphylococcus spp. were the most detected in the different samples. A high frequency of antimicrobial resistance has been observed and this could reflect the wide use of antimicrobials in pets, making the effectiveness of antibiotic treatment to become more complicated.

  3. BV和VVC患者阴道灌洗液中相关细胞因子水平检测及意义%Detection and significance of cytokines in cervicovaginal lavage fluid in patients with bacterial vaginosis and vulvovaginal candidiasis

    Institute of Scientific and Technical Information of China (English)

    冯贺强; 张学军; 戴随

    2011-01-01

    目的 提高细菌性阴道病(BV)和外阴阴道假丝酵母菌病(VVC)诊疗水平.方法 采集35例健康育龄妇女(对照组)、35例BV患者(BV组)、35例VVC患者(VVC组)阴道灌洗液,用ELISA法检测三组相关细胞因子(IL-2、IL-8、IFN-γ、IL-4、IL-13、IL-10、IgE)水平.结果 与对照组比较,BV组IL-2显著降低,IL-13、IL-4、IL-10显著升高,IL-8、IFN-γ、IgE无明显变化;VVC组IFN-γ显著降低,IL-2、IL-13、IL-4、IgE显著升高,IL-8、IL-10无显著变化.讨论 BV与VVC均存在Th1/Th2平衡失调,检测两种疾病局部细胞因子的变化有助于更好的控制感染.%Objective To improve the diagnosis and treament level of bacterial vaginosis(BV) and vulvovaginal candidiasis(VVC).Methods Cervicovaginal lavage fluid was collected from 35 healthy women in child-bearing age ( control group) ,35 patients with BC(BV group) ,35 patients with VVC (WC group).The level of cytokines (IL-2, IL-8,IFN-γ,IL-4,IL-13 ,IL-10,IgE)of the three groups were detected by ELISA.Results Compared with the control group, the IL-2 of BV group decreased significantly,IL-13,IL-4,IL-10 increased significantly,IL-8,IFN-γ,IgE had no significant change;the IFN-γof VVC group decreased significantly, IL-2,IL-13,IL-4,IgE increased obviously,IL-8,IL-10 had no significant change.Conclusions The un-balance of Th1/Th2 is common in BV and VVC, detecting the changes of local cytokine is helpful for controling their inflammation better.

  4. 食源性致病菌多重PCR快速检测研究进展%Research of Multiplex PCR Fast Detection on Food-borne Bacterial Pathogens

    Institute of Scientific and Technical Information of China (English)

    余倩; 黄梦娜

    2014-01-01

    Food safety has already been become the focus of attention. Food poisoning incidents have occurred by the pollution of food-borne bacterial pathogens frequently. It is quite complex and cost much time of traditional methods for detection of food-borne pathogens, so it can't checkout the pathogenic bacteria in food timely. All of these disadvantages limit its application. Multiplex-PCR can meet the requirement of checking out the pathogenic bacteria fast. This article introduced the theory, characteristic, composition of detection system and application of Multiplex-PCR. Multiplex-PCR had the advantages of high specificity, high sensitivity, simple operation and checking multiple pathogenic bacteria at the same time. Furthermore, multiplex-PCR can combine with fluorescence quantitative PCR or gene chip technology to establish a better system.%食品安全问题现在备受关注,食品中致病菌的污染造成的食物中毒事件时常发生,传统的食源性致病菌检测方法操作繁琐,耗时长,未能及时检验出食品中的致病菌,这些缺点限制了此方法的广泛应用。聚合酶链式反应(PCR)满足了快速检测致病菌的要求。主要介绍多重PCR快速检测食源性致病菌的原理、特点、检测体系的组成及其应用。多重PCR具有特异性强、灵敏度高、操作简便、可同时检测多种致病菌的优点,同时多重PCR技术可结合荧光定量PCR、基因芯片技术等建立一个更加完善的体系。

  5. Multiple bacterial species reside in chronic wounds

    DEFF Research Database (Denmark)

    Gjødsbøl, Kristine; Christensen, Jens Jørgen; Karlsmark, Tonny;

    2006-01-01

    species present were identified. More than one bacterial species were detected in all the ulcers. The most common bacteria found were Staphylococcus aureus (found in 93.5% of the ulcers), Enterococcus faecalis (71.7%), Pseudomonas aeruginosa (52.2%), coagulase-negative staphylococci (45.7%), Proteus...

  6. Interfering with bacterial gossip

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Tolker-Nielsen, Tim; Givskov, Michael

    2011-01-01

    defense. Antibiotics exhibit a rather limited effect on biofilms. Furthermore, antibiotics have an ‘inherent obsolescence’ because they select for development of resistance. Bacterial infections with origin in bacterial biofilms have become a serious threat in developed countries. Pseudomonas aeruginosa...... that appropriately target bacteria in their relevant habitat with the aim of mitigating their destructive impact on patients. In this review we describe molecular mechanisms involved in “bacterial gossip” (more scientifically referred to as quorum sensing (QS) and c-di-GMP signaling), virulence, biofilm formation...

  7. Analysis of the pediatric bacterial infectious disease detection of serum Prealbumin levels%儿科细菌感染性疾病检测血清前白蛋白水平分析

    Institute of Scientific and Technical Information of China (English)

    李桂霞

    2014-01-01

    Objective Analysis of Prealbumin (PA)in the diagnosis of disease in children with bacterial infection. Methods Using latex particle enhanced immuno turbidity than PA content were detected in 90 cases of disease in chil-dren with bacterial infection and 86 cases of healthy children in the serum samples of whole blood samples,and white blood cell (WBC)count,and a comparative analysis of test results.Results The level of serum WBC in experimental group is higher than those in the normal group,the difference between the two groups was statistically significant or highly significant (P <0.05 or P <0.01);the serum PA level of is lower than that of normal group,there was signifi-cant difference between two groups (P <0.01);the experiment group after treatment of 1 courses of PA increased, WBC decreased significantly.Compared with before treatment,there was statistically significant or highly significant difference (P <0.05 or P <0.01).Conclusion Serum PA is helpful for the diagnosis and curative effect observation of pediatric infectious diseases caused by bacteria,in the differential diagnosis of inflammation and tissue injury,efficacy, disease monitoring and prognosis has important clinical value,worthy of clinical application.%目的:分析前白蛋白(PA)在儿科细菌感染性疾病诊断中的临床意义。方法采用胶乳增强免疫比浊法检测90例细菌感染性疾病患儿和86例健康体检儿童的血清标本中 PA 含量,同时对全血样本中的白细胞(WBC)进行计数,并对检测结果进行比较分析。结果实验组 WBC 结果高于正常组,两组比较差异有统计学意义或高度统计学意义(P <0.05或 P <0.01);血清 PA 水平低于正常组,两组比较差异有统计学意义(P <0.01);实验组经1个疗程治疗后 PA 明显升高,WBC 降低明显。与治疗前比较,差异有统计学意义或高度统计学意义(P <0.05或 P <0.01)。结论血清 PA 检测有

  8. Bacterial coinfections in children with viral wheezing.

    Science.gov (United States)

    Lehtinen, P; Jartti, T; Virkki, R; Vuorinen, T; Leinonen, M; Peltola, V; Ruohola, A; Ruuskanen, O

    2006-07-01

    Bacterial coinfections occur in respiratory viral infections, but the attack rates and the clinical profile are not clear. The aim of this study was to determine bacterial coinfections in children hospitalized for acute expiratory wheezing with defined viral etiology. A total of 220 children aged 3 months to 16 years were investigated. The viral etiology of wheezing was confirmed by viral culture, antigen detection, serologic investigation, and/or PCR. Specific antibodies to common respiratory bacteria were measured from acute and convalescent serum samples. All children were examined clinically for acute otitis media, and subgroups of children were examined radiologically for sinusitis and pneumonia. Rhinovirus (32%), respiratory syncytial virus (31%), and enteroviruses (31%) were the most common causative viruses. Serologic evidence of bacterial coinfection was found in 18% of the children. Streptococcus pneumoniae (8%) and Mycoplasma pneumoniae (5%) were the most common causative bacteria. Acute otitis media was diagnosed in 44% of the children. Chest radiographs showed alveolar infiltrates in 10%, and paranasal radiographs and clinical signs showed sinusitis in 17% of the older children studied. Leukocyte counts and serum C-reactive protein levels were low in a great majority of patients. Viral lower respiratory tract infection in children is often associated with bacterial-type upper respiratory tract infections. However, coexisting bacterial lower respiratory tract infections that induce systemic inflammatory response are seldom detected.

  9. Bacterial mutagenicity assays: test methods.

    Science.gov (United States)

    Gatehouse, David

    2012-01-01

    The most widely used assays for detecting chemically induced gene mutations are those employing bacteria. The plate incorporation assay using various Salmonella typhimurium LT2 and E. coli WP2 strains is a short-term bacterial reverse mutation assay specifically designed to detect a wide range of chemical substances capable of causing DNA damage leading to gene mutations. The test is used worldwide as an initial screen to determine the mutagenic potential of new chemicals and drugs.The test uses several strains of S. typhimurium which carry different mutations in various genes of the histidine operon, and E. coli which carry the same AT base pair at the critical mutation site within the trpE gene. These mutations act as hot spots for mutagens that cause DNA damage via different mechanisms. When these auxotrophic bacterial strains are grown on a minimal media agar plates containing a trace of the required amino-acid (histidine or tryptophan), only those bacteria that revert to amino-acid independence (His(+) or Tryp(+)) will grow to form visible colonies. The number of spontaneously induced revertant colonies per plate is relatively constant. However, when a mutagen is added to the plate, the number of revertant colonies per plate is increased, usually in a dose-related manner.This chapter provides detailed procedures for performing the test in the presence and absence of a metabolic activation system (S9-mix), including advice on specific assay variations and any technical problems. PMID:22147566

  10. Bacterial Wound Culture

    Science.gov (United States)

    ... Home Visit Global Sites Search Help? Bacterial Wound Culture Share this page: Was this page helpful? Also known as: Aerobic Wound Culture; Anaerobic Wound Culture Formal name: Culture, wound Related ...

  11. Bacterial surface adaptation

    Science.gov (United States)

    Utada, Andrew

    2014-03-01

    Biofilms are structured multi-cellular communities that are fundamental to the biology and ecology of bacteria. Parasitic bacterial biofilms can cause lethal infections and biofouling, but commensal bacterial biofilms, such as those found in the gut, can break down otherwise indigestible plant polysaccharides and allow us to enjoy vegetables. The first step in biofilm formation, adaptation to life on a surface, requires a working knowledge of low Reynolds number fluid physics, and the coordination of biochemical signaling, polysaccharide production, and molecular motility motors. These crucial early stages of biofilm formation are at present poorly understood. By adapting methods from soft matter physics, we dissect bacterial social behavior at the single cell level for several prototypical bacterial species, including Pseudomonas aeruginosa and Vibrio cholerae.

  12. Bacterial intermediate filaments

    DEFF Research Database (Denmark)

    Charbon, Godefroid; Cabeen, M.; Jacobs-Wagner, C.

    2009-01-01

    Crescentin, which is the founding member of a rapidly growing family of bacterial cytoskeletal proteins, was previously proposed to resemble eukaryotic intermediate filament (IF) proteins based on structural prediction and in vitro polymerization properties. Here, we demonstrate that crescentin...

  13. Bacterial Meningitis in Infants

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2004-04-01

    Full Text Available A retrospective study of 80 infantile patients (ages 30-365 days; 47 male, 33 female with culture-proven bacterial meningitis seen over a 16 year period (1986-2001 is reported from Taiwan.

  14. Kynetic resazurin assay (KRA) for bacterial quantification of foodborne pathogens

    Science.gov (United States)

    Arenas, Yaxal; Mandel, Arkady; Lilge, Lothar

    2012-03-01

    Fast detection of bacterial concentrations is important for the food industry and for healthcare. Early detection of infections and appropriate treatment is essential since, the delay of treatments for bacterial infections tends to be associated with higher mortality rates. In the food industry and in healthcare, standard procedures require the count of colony-forming units in order to quantify bacterial concentrations, however, this method is time consuming and reports require three days to be completed. An alternative is metabolic-colorimetric assays which provide time efficient in vitro bacterial concentrations. A colorimetric assay based on Resazurin was developed as a time kinetic assay (KRA) suitable for bacterial concentration measurements. An optimization was performed by finding excitation and emission wavelengths for fluorescent acquisition. A comparison of two non-related bacteria, foodborne pathogens Escherichia coli and Listeria monocytogenes, was performed in 96 well plates. A metabolic and clonogenic dependence was established for fluorescent kinetic signals.

  15. Broad-range PCR, cloning and sequencing of the full 16S rRNA gene for detection of bacterial DNA in synovial fluid samples of Tunisian patients with reactive and undifferentiated arthritis

    OpenAIRE

    Siala, Mariam; Gdoura, Radhouane; Fourati, Hela; Rihl, Markus; Jaulhac, Benoit; Younes, Mohamed; Sibilia, Jean; Baklouti, Sofien; Bargaoui, Naceur; Sellami, Slaheddine; Sghir, Abdelghani; Hammami, Adnane

    2009-01-01

    Introduction Broad-range rDNA PCR provides an alternative, cultivation-independent approach for identifying bacterial DNA in reactive and other form of arthritis. The aim of this study was to use broad-range rDNA PCR targeting the 16S rRNA gene in patients with reactive and other forms of arthritis and to screen for the presence of DNA from any given bacterial species in synovial fluid (SF) samples. Methods We examined the SF samples from a total of 27 patients consisting of patients with rea...

  16. The bacterial lipocalins.

    Science.gov (United States)

    Bishop, R E

    2000-10-18

    The lipocalins were once regarded as a eukaryotic protein family, but new members have been recently discovered in bacteria. The first bacterial lipocalin (Blc) was identified in Escherichia coli as an outer membrane lipoprotein expressed under conditions of environmental stress. Blc is distinguished from most lipocalins by the absence of intramolecular disulfide bonds, but the presence of a membrane anchor is shared with two of its closest homologues, apolipoprotein D and lazarillo. Several common features of the membrane-anchored lipocalins suggest that each may play an important role in membrane biogenesis and repair. Additionally, Blc proteins are implicated in the dissemination of antibiotic resistance genes and in the activation of immunity. Recent genome sequencing efforts reveal the existence of at least 20 bacterial lipocalins. The lipocalins appear to have originated in Gram-negative bacteria and were probably transferred horizontally to eukaryotes from the endosymbiotic alpha-proteobacterial ancestor of the mitochondrion. The genome sequences also reveal that some bacterial lipocalins exhibit disulfide bonds and alternative modes of subcellular localization, which include targeting to the periplasmic space, the cytoplasmic membrane, and the cytosol. The relationships between bacterial lipocalin structure and function further illuminate the common biochemistry of bacterial and eukaryotic cells.

  17. 一种适用于 BDS/GPS 组合姿态测量的选星算法%A Satellite Selection Algorithm in BDS/GPS Combination Attitude Determination

    Institute of Scientific and Technical Information of China (English)

    王兵浩; 吕志伟; 吕金浩

    2015-01-01

    With the development of the Global Navigation Satellite System (GNSS ) , multi‐system application has became a hot spot of research .What comes with the mature of GNSS is the multiplied number of visible satellites w hich results in a more perfect structure of satellites and higher precision ,also the expanded design matrix and amount of calculation . The attitude determination based on GNSS has the advantages of low cost ,no error accumu‐lation ,weather free ,etc .Limited by the real‐time demand of attitude measuring ,a fast , reasonable algorithm of satellites selection in the GNSS attitude measurement is of great sig‐nificance .In this paper ,the author proposes an algorithm applicable to BDS/GPS combina‐tion attitude determination .This algorithm greatly reduces the amount of calculation in the process of one epoch on the premise of no too much loss of attitude measurement precision , w hich has a certain significance in the practical application .%随着GNSS系统的不断发展和完善,多卫星导航系统组合应用成为研究的热点。多系统的逐渐成熟带来的是单一历元可见卫星数量的成倍增加。卫星结构更加完善,解算精度更高,但计算量猛增。利用GNSS系统进行姿态测量具有组成简单、成本低、不受天气影响、没有误差积累等优点。受限于姿态测量的实时性要求,对观测到的卫星进行快速、合理的选择,在尽可能保证精度的前提下,满足实时性要求,对GNSS姿态测量具有重大的意义。提出了一种适用于BDS/G PS双系统组合姿态测量的选星算法,在保证姿态角测量精度较少损失的前提下,大大降低了单历元的计算量,在实际工程应用中具有一定的意义。

  18. BDS/GPS/GLONASS/GALILEO 组合卫星导航系统仿真分析%Simulation and Analysis of BDS/GPS/GLONASS/GALILEO Integrated Satellite Navigation System

    Institute of Scientific and Technical Information of China (English)

    潜成胜; 马大喜

    2013-01-01

    全球卫星定位系统因其高精度、全天候等优点而被广泛应用,但是单一导航系统容易受环境及人为干扰,导致在区域精度和连续性上有较大问题。本文对组合导航系统进行仿真,组合中国BDS、美国GPS、俄罗斯GLONASS和欧盟的GALILEO四个全球卫星导航系统,利用仿真数据对目前GPS单一系统、当前不完整组合系统、未来完整组合系统在赣州地区的几何精度衰减因子( GDOP)值、可见卫星数及导航精度进行对比分析。通过仿真结果可以发现,与单一的GPS系统相比,组合系统在可见卫星数、GDOP和导航精度上都有非常大的优势。%The Global satellite Positioning System is applied widely because of its advantages of high accuracy and all-weather operation .However ,a single satellite positioning system is more susceptible to environmental and human dis-turbance ,which causes significant problems about precision and continuity in region .In this paper ,an integrated naviga-tion system which includes the Chinese BDS ,the U.S.GPS,the Russian GLONASS and the EU’s GALILEO was applied to be simulated .And the simulated data was used to compare the current single GPS system ,the current incomplete inte-grated system and the future complete integrated system ’ s GDOP,the number of visible satellites and navigation accuracy in Ganzhou area .The simulation results reveal that the integrated navigation system is more advantage than the single GPS system in GDOP ,the number of visible satellites and navigation accuracy .

  19. Diagnosis of bacterial vaginosis

    Directory of Open Access Journals (Sweden)

    Đukić Slobodanka

    2013-01-01

    Full Text Available Bacterial vaginosis is a common, complex clinical syndrome characterized by alterations in the normal vaginal flora. When symptomatic, it is associated with a malodorous vaginal discharge and on occasion vaginal burning or itching. Under normal conditions, lactobacilli constitute 95% of the bacteria in the vagina. Bacterial vaginosis is associated with severe reduction or absence of the normal H2O2­producing lactobacilli and overgrowth of anaerobic bacteria and Gardnerella vaginalis, Atopobium vaginae, Mycoplasma hominis and Mobiluncus species. Most types of infectious disease are diagnosed by culture, by isolating an antigen or RNA/DNA from the microbe, or by serodiagnosis to determine the presence of antibodies to the microbe. Therefore, demonstration of the presence of an infectious agent is often a necessary criterion for the diagnosis of the disease. This is not the case for bacterial vaginosis, since the ultimate cause of the disease is not yet known. There are a variety of methods for the diagnosis of bacterial vaginosis but no method can at present be regarded as the best. Diagnosing bacterial vaginosis has long been based on the clinical criteria of Amsel, whereby three of four defined criteria must be satisfied. Nugent’s scoring system has been further developed and includes validation of the categories of observable bacteria structures. Up­to­date molecular tests are introduced, and better understanding of vaginal microbiome, a clear definition for bacterial vaginosis, and short­term and long­term fluctuations in vaginal microflora will help to better define molecular tests within the broader clinical context.

  20. Bacterial glycosyltransferase toxins.

    Science.gov (United States)

    Jank, Thomas; Belyi, Yury; Aktories, Klaus

    2015-12-01

    Mono-glycosylation of host proteins is a common mechanism by which bacterial protein toxins manipulate cellular functions of eukaryotic target host cells. Prototypic for this group of glycosyltransferase toxins are Clostridium difficile toxins A and B, which modify guanine nucleotide-binding proteins of the Rho family. However, toxin-induced glycosylation is not restricted to the Clostridia. Various types of bacterial pathogens including Escherichia coli, Yersinia, Photorhabdus and Legionella species produce glycosyltransferase toxins. Recent studies discovered novel unexpected variations in host protein targets and amino acid acceptors of toxin-catalysed glycosylation. These findings open new perspectives in toxin as well as in carbohydrate research.

  1. Clinical Significance of CRP and PCT Detection for the Diagnosis of Bacterial Pneumonia and Mycoplasma Pneumonia in Children%CRP及PCT检测对儿童细菌性肺炎及支原体肺炎诊断的临床意义

    Institute of Scientific and Technical Information of China (English)

    屠强

    2013-01-01

    目的:探讨C反应蛋白(CRP, C-reactive protein)及降钙素原(PCT, Procalcitonin)与儿童细菌性肺炎及支原体肺炎发病及病程的相关性。方法采用透射比浊法对140例儿童支原体肺炎及细菌性肺炎和70例健康受试者进行了检测。采用SPSS11.0软件包统计分析各组别间的差异性。结果细菌性肺炎组及支原体肺炎组的CRP水平均高于正常对照组,差异具有统计学意义(P<0.05)。细菌性肺炎组的CRP水平较支原体肺炎的CRP水平高(P<0.05)。细菌性肺炎及支原体肺炎组经治疗3d后与治疗前相比, CPR水平均显著性降低(P<0.05)。细菌性肺炎组的PCT水平高于正常对照组,有统计学意义(P<0.01)。此外,细菌性肺炎的PCT水平亦高于支原体肺炎组。治疗3d后细菌性肺炎组的PCT水平较支原体肺炎组高,两组之间有显著性差异(P<0.01)。结论 CRP对儿童细菌性肺炎和支原体肺炎反应性较好,可以作为临床诊断的依据;PCT对于细菌性肺炎有较好的指示作用,且对疾病的进程判断有参考价值。%Objective To investigate the correlation of C-reactive protein (CRP) and procalcitonin (PCT) level and diagnosis and prognosis of bacterial pneumonia and mycoplasma pneumonia in children.Methods Turbidimetric method was applied to detect the concentration of CRP and PCT in 140 cases children mycoplasma pneumonia and bacterial pneumonia respectively,and 70 healthy subjects were also enrolled for controls. SPSS11.0 software package Statistical was used to analysis the differences between groups. Results The results indicated that the CRP level in children with bacterial pneumonia or mycoplasma pneumonia was higher than the normal controls (P<0.05).CRP level in children with bacterial pneumonia group was higher than those with mycoplasma pneumonia (P<0.05).The CRP level in childeren accepted treatment for bacterial pneumonia or mycoplasma

  2. Bd/s -> mu+ mu- in ATLAS

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00215268; The ATLAS collaboration

    2016-01-01

    The ATLAS Experiment has conducted a search for the rare decays of Bs and Bd into mu+mu-. 25 fb−1 of integrated luminosity of proton-proton collisions collected during LHC Run 1 were studied and new results were obtained, as presented in this talk. An upper limit is set on the Bd to mu+mu- branching ratio of BR(Bd to mu+mu-) < 4.2×10−10 at 95% confidence level. For Bs, ATLAS measurement yields the branching ratio BR(Bs to mu+mu-)=(0.9+1.1−0.8)×10−9. The result is consistent with the Standard Model expectation and other available measurements.

  3. Bd/s -> mu+ mu- in ATLAS

    CERN Document Server

    Guenther, Jaroslav; The ATLAS collaboration

    2016-01-01

    The ATLAS Experiment has conducted a search for the rare decays of Bs and Bd into mu+mu-. 25 fb−1 of integrated luminosity of proton-proton collisions collected during LHC Run 1 were studied to provide new results presented in this talk. An upper limit is set on the branching ratio BR(Bd to mu+mu-) < 4.2×10−10 at 95% confidence level. For Bs, ATLAS measurement yields the branching ratio BR(Bs to mu+mu-)=(0.9+1.1−0.8)×10−9. The result is consistent with the Standard Model expectation and other available measurements.

  4. Cooperative Model of Bacterial Sensing

    CERN Document Server

    Shi, Y; Shi, Yu; Duke, Thomas

    1998-01-01

    Bacterial chemotaxis is controlled by the signalling of a cluster of receptors. A cooperative model is presented, in which coupling between neighbouring receptor dimers enhances the sensitivity with which stimuli can be detected, without diminishing the range of chemoeffector concentration over which chemotaxis can operate. Individual receptor dimers have two stable conformational states: one active, one inactive. Noise gives rise to a distribution between these states, with the probability influenced by ligand binding, and also by the conformational states of adjacent receptor dimers. The two-state model is solved, based on an equivalence with the Ising model in a randomly distributed magnetic field. The model has only two effective parameters, and unifies a number of experimental findings. According to the value of the parameter comparing coupling and noise, the signal can be arbitrarily sensitive to changes in the fraction of receptor dimers to which ligand is bound. The counteracting effect of a change of...

  5. Seizures Complicating Bacterial Meningitis

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2004-09-01

    Full Text Available The clinical data of 116 patients, 1 month to <5 years of age, admitted for bacterial meningitis, and grouped according to those with and without seizures during hospitalization, were compared in a study at Buddhist Dalin Tzu Chi General Hospital, Chang Gung Memorial Hospital and other centers in Taiwan.

  6. Bacterial extracellular lignin peroxidase

    Science.gov (United States)

    Crawford, Donald L.; Ramachandra, Muralidhara

    1993-01-01

    A newly discovered lignin peroxidase enzyme is provided. The enzyme is obtained from a bacterial source and is capable of degrading the lignin portion of lignocellulose in the presence of hydrogen peroxide. The enzyme is extracellular, oxidative, inducible by lignin, larch wood xylan, or related substrates and capable of attacking certain lignin substructure chemical bonds that are not degradable by fungal lignin peroxidases.

  7. Bacterial Skin Infections

    Science.gov (United States)

    ... or scraped, the injury should be washed with soap and water and covered with a sterile bandage. Petrolatum may be applied to open areas to keep the tissue moist and to try to prevent bacterial invasion. Doctors recommend that people do not use ...

  8. Vimentin in Bacterial Infections

    DEFF Research Database (Denmark)

    Mak, Tim N; Brüggemann, Holger

    2016-01-01

    filaments (IFs). IFs have not only roles in maintaining the structural integrity of the cell, but they are also involved in many cellular processes including cell adhesion, immune signaling, and autophagy, processes that are important in the context of bacterial infections. Here, we summarize the knowledge...

  9. Bacterial microflora of nectarines

    Science.gov (United States)

    Microflora of fruit surfaces has been the best source of antagonists against fungi causing postharvest decays of fruit. However, there is little information on microflora colonizing surfaces of fruits other than grapes, apples, and citrus fruit. We characterized bacterial microflora on nectarine f...

  10. Modeling intraocular bacterial infections.

    Science.gov (United States)

    Astley, Roger A; Coburn, Phillip S; Parkunan, Salai Madhumathi; Callegan, Michelle C

    2016-09-01

    Bacterial endophthalmitis is an infection and inflammation of the posterior segment of the eye which can result in significant loss of visual acuity. Even with prompt antibiotic, anti-inflammatory and surgical intervention, vision and even the eye itself may be lost. For the past century, experimental animal models have been used to examine various aspects of the pathogenesis and pathophysiology of bacterial endophthalmitis, to further the development of anti-inflammatory treatment strategies, and to evaluate the pharmacokinetics and efficacies of antibiotics. Experimental models allow independent control of many parameters of infection and facilitate systematic examination of infection outcomes. While no single animal model perfectly reproduces the human pathology of bacterial endophthalmitis, investigators have successfully used these models to understand the infectious process and the host response, and have provided new information regarding therapeutic options for the treatment of bacterial endophthalmitis. This review highlights experimental animal models of endophthalmitis and correlates this information with the clinical setting. The goal is to identify knowledge gaps that may be addressed in future experimental and clinical studies focused on improvements in the therapeutic preservation of vision during and after this disease. PMID:27154427

  11. Detectability of substellar companions around white dwarfs with Gaia

    CERN Document Server

    Silvotti, Roberto; Lattanzi, Mario; Morbidelli, Roberto

    2014-01-01

    To date not a single-bona fide planet has been identified orbiting a single white dwarf. In fact we are ignorant about the final configuration of >95% of planetary systems. Theoretical models predict a gap in the final distribution of orbital periods, due to the opposite effects of stellar mass loss (planets pushed outwards) and tidal interactions (planets pushed inwards) during the RGB and the AGB stellar expansions. Over its five year primary mission, Gaia is expected to astrometrically detect the first (few tens of) WD massive planets/BDs giving first evidence that WD planets exist, at least those in wide orbits. In this article we present preliminary results of our simulations of what Gaia should be able to find in this field.

  12. Drop Analysis in Infants with Bacterial Pneumonia in the Diagnosis of Procalcitonin Detection and Blood Culture%降钙素原检测与血培养在婴幼儿细菌性肺炎诊断中的作用分析

    Institute of Scientific and Technical Information of China (English)

    陈贵英

    2015-01-01

    Objective To compare the procalcitonin and blood culture results in the diagnosis of bacterial pneumonia in infants.Methods Choose 36 cases of infants with bacterial pneumonia,fasting blood,for procalcitonin detection,blood culture,the comparison results.Results Procalcitonin blood culture positive rate was 52.78%;the total positive rate was 25%.Conclusion In the diagnosis of infantile bacterial pneumonia,procalcitonin has more advantage.%目的对比降钙素原与血培养在婴幼儿细菌性肺炎诊断中效果。方法选取婴幼儿细菌性肺炎患儿36例,抽取空腹静脉血,行降钙素原、血培养检测,对比结果。结果降钙素原阳性率为52.78%;血培养总阳性率为25.00%。结论在婴幼儿细菌性肺炎诊断中,降钙素原检测具有更大的优势。

  13. Comparison between a Broad-Range Real-Time and a Broad-Range End-Point PCR Assays for the Detection of Bacterial 16S rRNA in Clinical Samples.

    Science.gov (United States)

    Meddeb, Mariam; Koebel, Christelle; Jaulhac, Benoît; Schramm, Frédéric

    2016-01-01

    Broad range PCR targeting the 16S rRNA gene is widely used to test clinical samples for the presence of bacterial DNA. End-point 16S PCR is both time-consuming and at high risk of cross-contamination. Prior to the replacement of the 16S end-point PCR assay routinely used in our clinical laboratory by a new 16S real-time PCR assay, we aimed to compare the performances of both techniques for the direct diagnosis of bacterial infections in clinical samples. In this prospective study, 129 clinical samples were included for direct comparison of both techniques. The sensitivity of 16S real-time PCR assay (76%) was significantly higher than that of end-point 16S PCR assay (41%) (pPCR assays did not differ significantly (p=0.43). The 16S real-time PCR assay yielded an etiological diagnosis in 19% of culture-negative samples. It constitutes a reliable and complementary diagnostic tool to the bacterial culture.

  14. Heme uptake in bacterial pathogens

    OpenAIRE

    Contreras, Heidi; Chim, Nicholas; Credali, Alfredo; Goulding, Celia W.

    2014-01-01

    Iron is an essential nutrient for the survival of organisms. Bacterial pathogens possess specialized pathways to acquire heme from their human hosts. In this review, we present recent structural and biochemical data that provide mechanistic insights into several bacterial heme uptake pathways, encompassing the sequestration of heme from human hemoproteins to secreted or membrane-associated bacterial proteins, the transport of heme across bacterial membranes, and the degradation of heme within...

  15. A portable biosensor system for bacterial concentration measurements in cow's raw milk

    OpenAIRE

    Grossi, Marco; Lanzoni, Massimo; Pompei, Anna; Lazzarini, Roberto; Matteuzzi, Diego; Ricco, Bruno

    2011-01-01

    Bacterial detection is of primary importance in many fields, such as food and environmental monitoring. Measurements of bacterial concentration are traditionally carried out by means of the Standard Plate Count technique, a reliable method for microbial screening that, however, features long response time and is carried out by qualified personnel in microbiology laboratories. The impedance technique for bacterial concentration detection represents a method very competitive with Standard Plate...

  16. C-反应蛋白检测在小儿细菌性肺炎与支原体肺炎中的临床比较%Clinical value of detection of C-reaction protein in diagnosis of pediatric bacterial pneumonia and Mycoplasma pneumonia:a comparative study

    Institute of Scientific and Technical Information of China (English)

    石丰月

    2013-01-01

    OBJECTIVE To study the clinical value of C-reactie protein (CRP) detection in diagnosis of the pediatric bacterial pneumonia and the Mycoplasma pneumonia so as to guide the diagnosis of infantile pneumonia.METHODS The children with bacterial pneumonia (the bacterial pneumonia group) and the children with Mycoplasma pneumonia (the Mycoplasma pneumonia group),who were treated in the pediatrics department from Sep 2010 to Sep 2012,were enrolled in the study,the healthy children receiving the medical examination (the control group)were also selected,with 80 cases in each group,then the change of CRP level was determined.RESULTS The CRP level of the control group was (3.24 ±0.45)mg/L,the bacterial pneumonia group before treatment (44.03±5.83) mg/L,the bacterial pneumonia group 3 days after the treatment (15.12±6.21) mg/L,the Mycoplasma pneumonia group before treatment (13.97±4.96) mg/L,the Mycoplasma pneumonia group 3 days after the treatment (5.29 ± 2.33) mg/L,the CRP level of the bacterial pneumonia group and the Mycoplasma pneumonia group before the treatment was significantly higher than that of the control group (P<0.05),the CRP level of the bacterial pneumonia group was higher than that of the Mycoplasma pneumonia group (P<0.05),the CRP level of the bacterial pneumonia group 3 days after treatment was higher than that of the Mycoplasma pneumonia group (P<0.05),the difference in the CRP level before and after the treatment between the bacterial pneumonia group and the Mycoplasma pneumonia group was statistically significant (P< 0.05).The positive rates of the CRP of the bacterial pneumonia group were 100.00% before the treatment and 52.50% 3 days after the treatment,which were respectively 66.25 % and 21.25 % in the Mycoplasma pneumonia group,the difference in the positive rate before and after the treatment between the bacterial pneumonia group and the Mycoplasmapneumonia group was statistically significant (P<0.05).CONCLUSION The positive

  17. Luminescent Bacterial Sensors Made from Immobilized Films of Photobacterium Phosphoreum

    Institute of Scientific and Technical Information of China (English)

    YIN Ji-qiu; LI Xiao-zhou; ZHOU Chi; ZHANG Yi-hua

    2005-01-01

    A kind of luminous bacterial sensors that can quickly detect the acute toxicity of environmental pollutants were developed. The method is based on the detection of the cellular light of bright luminous bacillus by means of fixing cells so as to detect acute toxicity of luminous bacillus. The bacterial sensor is composed of immobilized film of photobacterium phosphoreum. These bacterial films are sensitive to detecting the toxicoids, which are difficult or even impossible to be measured by traditional analytical chemistry methods. The films should be stored at 4 ℃ and the stability of the sensors exceeds 1 month with no measurable deterioration of the signal. These results demonstrate that the immobilized film of P.phosphreum can be used to develop the on-line environmental contamination monitor.

  18. Bacterial chemoreceptors and chemoeffectors.

    Science.gov (United States)

    Bi, Shuangyu; Lai, Luhua

    2015-02-01

    Bacteria use chemotaxis signaling pathways to sense environmental changes. Escherichia coli chemotaxis system represents an ideal model that illustrates fundamental principles of biological signaling processes. Chemoreceptors are crucial signaling proteins that mediate taxis toward a wide range of chemoeffectors. Recently, in deep study of the biochemical and structural features of chemoreceptors, the organization of higher-order clusters in native cells, and the signal transduction mechanisms related to the on-off signal output provides us with general insights to understand how chemotaxis performs high sensitivity, precise adaptation, signal amplification, and wide dynamic range. Along with the increasing knowledge, bacterial chemoreceptors can be engineered to sense novel chemoeffectors, which has extensive applications in therapeutics and industry. Here we mainly review recent advances in the E. coli chemotaxis system involving structure and organization of chemoreceptors, discovery, design, and characterization of chemoeffectors, and signal recognition and transduction mechanisms. Possible strategies for changing the specificity of bacterial chemoreceptors to sense novel chemoeffectors are also discussed.

  19. Bacterial Colony Optimization

    Directory of Open Access Journals (Sweden)

    Ben Niu

    2012-01-01

    Full Text Available This paper investigates the behaviors at different developmental stages in Escherichia coli (E. coli lifecycle and developing a new biologically inspired optimization algorithm named bacterial colony optimization (BCO. BCO is based on a lifecycle model that simulates some typical behaviors of E. coli bacteria during their whole lifecycle, including chemotaxis, communication, elimination, reproduction, and migration. A newly created chemotaxis strategy combined with communication mechanism is developed to simplify the bacterial optimization, which is spread over the whole optimization process. However, the other behaviors such as elimination, reproduction, and migration are implemented only when the given conditions are satisfied. Two types of interactive communication schemas: individuals exchange schema and group exchange schema are designed to improve the optimization efficiency. In the simulation studies, a set of 12 benchmark functions belonging to three classes (unimodal, multimodal, and rotated problems are performed, and the performances of the proposed algorithms are compared with five recent evolutionary algorithms to demonstrate the superiority of BCO.

  20. [Bacterial diseases of rape].

    Science.gov (United States)

    Zakharova, O M; Mel'nychuk, M D; Dankevych, L A; Patyka, V P

    2012-01-01

    Bacterial destruction of the culture was described and its agents identified in the spring and winter rape crops. Typical symptoms are the following: browning of stem tissue and its mucilagization, chlorosis of leaves, yellowing and beginning of soft rot in the place of leaf stalks affixion to stems, loss of pigmentation (violet). Pathogenic properties of the collection strains and morphological, cultural, physiological, and biochemical properties of the agents of rape's bacterial diseases isolated by the authors have been investigated. It was found that all the isolates selected by the authors are highly or moderately aggressive towards different varieties of rape. According to the complex of phenotypic properties 44% of the total number of isolates selected by the authors are related to representatives of the genus Pseudomonas, 37% - to Xanthomonas and 19% - to Pectobacterium. PMID:23293826

  1. Methods to classify bacterial pathogens in cystic fibrosis

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Nielsen, Xiaohui Chen; Johansen, Ulla;

    2011-01-01

    Many bacteria can be detected in CF sputum, pathogenic and commensal. Modified Koch's criteria for identification of established and emerging CF pathogens are therefore described. Methods are described to isolate bacteria and to detect bacterial biofilms in sputum or lung tissue from CF patients ...

  2. Bacterial transformation of terpenoids

    International Nuclear Information System (INIS)

    Data on the bacterial transformation of terpenoids published in the literature in the past decade are analyzed. Possible pathways for chemo-, regio- and stereoselective modifications of terpenoids are discussed. Considerable attention is given to new technological approaches to the synthesis of terpenoid derivatives suitable for the use in the perfume and food industry and promising as drugs and chiral intermediates for fine organic synthesis. The bibliography includes 246 references

  3. Supramolecular bacterial systems

    OpenAIRE

    Sankaran, Shrikrishnan

    2015-01-01

    For nearly over a decade, a wide variety of dynamic and responsive supramolecular architectures have been investigated and developed to address biological systems. Since the non-covalent interactions between individual molecular components in such architectures are similar to the interactions found in living systems, it was possible to integrate chemically-synthesized and naturally-occurring components to create platforms with interesting bioactive properties. Bacterial cells and recombinant ...

  4. Bacterial Colony Optimization

    OpenAIRE

    Ben Niu; Hong Wang

    2012-01-01

    This paper investigates the behaviors at different developmental stages in Escherichia coli (E. coli) lifecycle and developing a new biologically inspired optimization algorithm named bacterial colony optimization (BCO). BCO is based on a lifecycle model that simulates some typical behaviors of E. coli bacteria during their whole lifecycle, including chemotaxis, communication, elimination, reproduction, and migration. A newly created chemotaxis strategy combined with communication mechanism i...

  5. Endophytic bacterial community of a Mediterranean marine angiosperm (Posidonia oceanica

    Directory of Open Access Journals (Sweden)

    Neus eGarcias-Bonet

    2012-09-01

    Full Text Available Bacterial endophytes are crucial for the survival of many terrestrial plants, but little is known about the presence and importance of bacterial endophytes of marine plants. We conducted a survey of the endophytic bacterial community of the long-living Mediterranean marine angiosperm Posidonia oceanica in surface-sterilized tissues (roots, rhizomes and leaves by DGGE. A total of 26 Posidonia oceanica meadows around the Balearic Islands were sampled, and the band patterns obtained for each meadow were compared for the three sampled tissues. Endophytic bacterial sequences were detected in most of the samples analyzed. A total of 34 OTUs (Operational Taxonomic Units were detected. The main OTUs of endophytic bacteria present in P. oceanica tissues belonged primarily to Proteobacteria (α, γ and δ subclasses and Bacteroidetes. The OTUs found in roots significantly differed from those of rhizomes and leaves. Moreover, some OTUs were found to be associated to each type of tissue. Bipartite network analysis revealed differences in the bacterial endophyte communities present on different islands. The results of this study provide a pioneering step toward the characterization of the endophytic bacterial community associated with tissues of a marine angiosperm and reveal the presence of bacterial endophytes that differed among locations and tissue types.

  6. Bacterial migration through punctured surgical gloves under real surgical conditions

    OpenAIRE

    Heidecke Claus-Dieter; Assadian Ojan; Stanislawski Natalie; Goerdt Anna-Maria; Hübner Nils-Olaf; Kramer Axel; Partecke Lars

    2010-01-01

    Abstract Background The aim of this study was to confirm recent results from a previous study focussing on the development of a method to measure the bacterial translocation through puncture holes in surgical gloves under real surgical conditions. Methods An established method was applied to detect bacterial migration from the operating site through the punctured glove. Biogel™ double-gloving surgical gloves were used during visceral surgeries over a 6-month period. A modified Gaschen-bag met...

  7. Rheumatoid arthritis and bacterial infections

    Directory of Open Access Journals (Sweden)

    N L Prokopjeva

    2008-01-01

    Full Text Available To study features of bacterial infections course in pts with rheumatoid arthritis (RA and changes of laboratory measures after focus of infection sanation. Material and methods. 46 pts with definite rheumatoid arthritis were examined at the time of comorbid infection (Cl detection and after infection focus sanation. Bacteriological test with evaluation of flora sensitivity to antibiotics by disco-diffusion method was performed at baseline and after the course of antibacterial therapy to assess its efficacy. Hemogram, serum fibrinogen, rheumatoid factor, circulating immune complexes (CIC, C-reactive protein levels were assessed. Serum interleukin (IL 1(3, IL6 and neopterin concentrations were examined by immune-enzyme assay in a part of pts. Typical clinical features of Cl were present in only 28 (60,9% pts. 13 (28,3% pts had fever, 12 (26,0% — leukocytosis, 15 (32,6% — changes of leucocyte populations. Some laboratory measures (thrombocytes, fibrinogen, CIC, neopterin levels significantly decreased (p<0,05 after infection focus sanation without correction of disease modifying therapy. Cl quite often develop as asymptomatic processes most often in pts with high activity and can induce disturbances promoting appearance of endothelial dysfunction, atherothrombosis and reduction of life duration. So timely detection and proper sanation of infection focuses should be performed in pts with RA

  8. Prevention of bacterial foodborne disease using nanobiotechnology

    Directory of Open Access Journals (Sweden)

    Billington C

    2014-08-01

    Full Text Available Craig Billington, J Andrew Hudson, Elaine D'SaFood Safety Programme, ESR, Ilam, Christchurch, New Zealand Abstract: Foodborne disease is an important source of expense, morbidity, and mortality for society. Detection and control constitute significant components of the overall management of foodborne bacterial pathogens, and this review focuses on the use of nanosized biological entities and molecules to achieve these goals. There is an emphasis on the use of organisms called bacteriophages (phages: viruses that infect bacteria, which are increasingly being used in pathogen detection and biocontrol applications. Detection of pathogens in foods by conventional techniques is time-consuming and expensive, although it can also be sensitive and accurate. Nanobiotechnology is being used to decrease detection times and cost through the development of biosensors, exploiting specific cell-recognition properties of antibodies and phage proteins. Although sensitivity per test can be excellent (eg, the detection of one cell, the very small volumes tested mean that sensitivity per sample is less compelling. An ideal detection method needs to be inexpensive, sensitive, and accurate, but no approach yet achieves all three. For nanobiotechnology to displace existing methods (culture-based, antibody-based rapid methods, or those that detect amplified nucleic acid it will need to focus on improving sensitivity. Although manufactured nonbiological nanoparticles have been used to kill bacterial cells, nanosized organisms called phages are increasingly finding favor in food safety applications. Phages are amenable to protein and nucleic acid labeling, and can be very specific, and the typical large "burst size" resulting from phage amplification can be harnessed to produce a rapid increase in signal to facilitate detection. There are now several commercially available phages for pathogen control, and many reports in the literature demonstrate efficacy against a

  9. Simultaneous detection of Neisseria meningitidis, Haemophilus influenzae and Streptococcus sp. by polymerase chain reaction for the diagnosis of bacterial meningits Detecção simultânea da Neisseria meningitidis, Haemophilus influenzae e Streptococcus sp. pela reação em cadeia da polimerase no diagnóstico das meningites bacterianas

    Directory of Open Access Journals (Sweden)

    Luciane Failace

    2005-12-01

    Full Text Available The simultaneous detection of Neisseria meningitidis, Haemophilus influenzae, and Streptococcus sp. was assessed by polymerase chain reaction (PCR for the diagnosis of bacterial meningitis, as well as the applicability of PCR as a routine test. A cohort study was carried out with 182 children (2 months to 12 years of age with suspicion of bacterial meningitis. Routine tests identified the etiologic agent in 65/84 children whose clinical status and laboratory findings suggested the presence of bacterial meningitis. Bacterial meningitis was ruled out in 98 children. In 19 children, the etiologic diagnosis was not possible using standard methods; in 14 of these patients, the etiologic agent was identified by PCR (N. meningitidis=12; H. influenzae=1; Streptococcus sp.=1. The sensitivity of PCR was 88.1%; specificity, 99.0%; positive predictive value, 98.7%; and negative predictive, 90.1%. PCR is a useful complementary diagnostic technique, especially when Gram stain, culture, or antigenic detection are negative or inconclusive.Avaliamos o desempenho da reação em cadeia da polimerase (PCR para detecção simultânea da Neisseria meningitidis, Haemophilus influenzae e Streptococcus sp. no diagnóstico das meningites bacterianas e sua aplicabilidade na rotina diagnóstica. Foi realizado um estudo de coorte com 182 crianças apresentando suspeita de meningite bacteriana. Em 84, havia alterações clínicas e laboratoriais sugestivas de meningite bacteriana. Destas, 65 tiveram o agente etiológico identificado pelos métodos laboratoriais de rotina e 19 ficaram sem diagnóstico etiológico. Em 98 pacientes foi excluído o diagnóstico de meningite bacteriana. Analisando o desempenho da PCR encontramos sensibilidade de 88,1%, especificidade de 99,0% e valores preditivos positivo e negativo de 98,7% e 90,1% respectivamente. Nos 19 pacientes com meningite bacteriana mas sem diagnóstico etiológico a PCR detectou microrganismos em 14, sendo 12 N

  10. Detection of Vibrio Cholerae in Turtles by Real Time Polymerase Chain Reaction, Colloidal Gold Immunochromatographic Assay and Conventional Bacterial Culture%实时荧光PCR法、胶体金法和培养法检测甲鱼中霍乱弧菌

    Institute of Scientific and Technical Information of China (English)

    颜淑妩; 李哲婷; 邓婵

    2012-01-01

    目的 优化水产品甲鱼中霍乱弧菌的检测程序,提高甲鱼中霍乱弧菌检出率.方法 用实时荧光PCR、常规细菌培养、胶体金法同时对甲鱼中霍乱弧菌进行检测,并用实时荧光PCR法检测标本中霍乱弧菌ctx基因.结果 共检测185份甲鱼样品,其中实时荧光PCR法检出28份霍乱弧菌核酸阳性,阳性率为15.14%;6份ctx基因核酸阳性,阳性率21.43% (6/28).常规细菌培养法分离出2株菌株,一株为O139群霍乱弧菌,一株为小川型霍乱弧菌,用实时荧光PCR检测这两株纯培养菌株或原始标本,霍乱弧菌ctx基因均为阴性;胶体金法未检出阳性标本.结论 对于水产品标本,可先用实时荧光PCR法筛检霍乱弧菌,阳性标本再进行传统细菌分离培养,以提高霍乱弧菌菌株的检出率;同时阳性标本进行霍乱弧菌ctx基因核酸检测,如也为阳性,需提高警惕,加强流行病学上的预防控制措施,及时防范霍乱疫情的发生.%Objective To optimize the detection procedure of Vibrio Cholerae (v. cholerae) and increase its detection rate in turtles. Methods The v. cholerae in turtles was detected by real time polymerase chain reaction (real time PCR), conventional bacterial culture and colloidal gold immunochrornatographic assay, and the ctx gene of the virus was detected by real time PCR. Results Real time PCR revealed that among 185 turtle samples, 28 ones were positive with v. cholerae nucleic acid, with a positive rate of 15.14% (28/185), and six samples were positive with ctx gene, with a positive rate of 21.43% (6/ 28). Two strains of v.cholerae were isolated by conventional bacterial culture, Vibrio cholerae O139, and Vibrio cholerae Ol serotype Ogawa. Neither the pure cultures nor the original samples of both stains were positive with ctx gene. No v. cholerae was detected by colloidal gold immunochromatugraphic assay. Conclusions For V. cholerae detection in seafood samples, real time PCR can be first used for

  11. The Application of White Blood Cel s (WBC) and C-reactive Protein Joint Detection in the Diagnosis of Pediatric Bacterial Infection Disease%C反应蛋白和白细胞(WBC)联合检测在儿科细菌性感染疾病诊断中的应用

    Institute of Scientific and Technical Information of China (English)

    林华峰; 杜豪伟

    2013-01-01

    目的:探讨C反应蛋白(CRP)和白细胞(WBC)联合检测在儿科各种细菌感染疾病诊断中的应用。方法选择102例细菌性感染患儿和75例无感染性疾病患儿进行CRP和白细胞(WBC)联合检测。结果感染组CRP、WBC阳性率较无感染性疾病明显增高,差异有统计学意义(P<0.05);感染组CRP阳性率较WBC阳性率明显高,差异有统计学意义(P<0.05)。结论 CRP和WBC的联合检测对儿科各种感染性疾病的早期诊断和有效监察治疗效果,及合理使用抗生素和判断预后方面有一定意义。%Objective To evaluate the role of c-reactive protein (CRP) and white blood cells (WBC) detection in the diagnosis of pediatric bacterial infection disease. Methods Choose 102 cases of children with bacterial infection and 75 cases of children with infectious disease for CRP and white blood cells (WBC) joint detection. Results CRP, WBC infection group were significantly higher, less infectious diseases, the difference was statistically significant (P<0.05);infection group of CRP positive rate compared with the positive ratio in the WBC is high, the difference was statistically significant (P<0.05). Conclusion Joint detection of CRP and WBC in pediatric infectious diseases early diagnosis and effective supervision of all kinds of effect, and has certain significance to reasonable use of antibiotics and prognosis.

  12. Spontaneous bacterial peritonitis

    Institute of Scientific and Technical Information of China (English)

    Anastasios Koulaouzidis; Shivaram Bhat; Athar A Saeed

    2009-01-01

    Since its initial description in 1964, research has transformed spontaneous bacterial peritonitis (SBP) from a feared disease (with reported mortality of 90%) to a treatable complication of decompensated cirrhosis,albeit with steady prevalence and a high recurrence rate. Bacterial translocation, the key mechanism in the pathogenesis of SBP, is only possible because of the concurrent failure of defensive mechanisms in cirrhosis.Variants of SBP should be treated. Leucocyte esterase reagent strips have managed to shorten the 'tap-toshot' time, while future studies should look into their combined use with ascitic fluid pH. Third generation cephalosporins are the antibiotic of choice because they have a number of advantages. Renal dysfunction has been shown to be an independent predictor of mortality in patients with SBP. Albumin is felt to reduce the risk of renal impairment by improving effective intravascular volume, and by helping to bind proinflammatory molecules. Following a single episode of SBP, patients should have long-term antibiotic prophylaxis and be considered for liver transplantation.

  13. Antimicrobials for bacterial bioterrorism agents.

    Science.gov (United States)

    Sarkar-Tyson, Mitali; Atkins, Helen S

    2011-06-01

    The limitations of current antimicrobials for highly virulent pathogens considered as potential bioterrorism agents drives the requirement for new antimicrobials that are suitable for use in populations in the event of a deliberate release. Strategies targeting bacterial virulence offer the potential for new countermeasures to combat bacterial bioterrorism agents, including those active against a broad spectrum of pathogens. Although early in the development of antivirulence approaches, inhibitors of bacterial type III secretion systems and cell division mechanisms show promise for the future.

  14. Predictive value of decoy receptor 3 in postoperative nosocomial bacterial meningitis.

    Science.gov (United States)

    Liu, Yong-Juan; Shao, Li-Hua; Wang, Qian; Zhang, Jian; Ma, Rui-Ping; Liu, Hai-Hong; Dong, Xiao-Meng; Ma, Li-Xian

    2014-11-03

    Nosocomial bacterial meningitis requires timely treatment, but what is difficult is the prompt and accurate diagnosis of this disease. The aim of this study was to assess the potential role of decoy receptor 3 (DcR3) levels in the differentiation of bacterial meningitis from non-bacterial meningitis. A total of 123 patients were recruited in this study, among them 80 patients being with bacterial meningitis and 43 patients with non-bacterial meningitis. Bacterial meningitis was confirmed by bacterial culture of cerebrospinal fluid (CSF) culture and enzyme-linked immunosorbent assay (ELISA) was used to detect the level of DcR3 in CSF. CSF levels of DcR3 were statistically significant between patients with bacterial meningitis and those with non-bacterial meningitis (pbacterial meningitis received antibiotic>24 h before CSF sampling, which was much higher than that of non-bacterial meningitis. CSF leucocyte count yielded the highest diagnostic value, with an area under the receiver operating characteristic curve (ROC) of 0.928, followed by DcR3. At a critical value of 0.201 ng/mL for DcR3, the sensitivity and specificity were 78.75% and 81.40% respectively. DcR3 in CSF may be a valuable predictor for differentiating patients with bacterial meningitis from those with non-bacterial meningitis. Further studies are needed for the validation of this study.

  15. Bacterial acquisition in juveniles of several broadcast spawning coral species.

    Directory of Open Access Journals (Sweden)

    Koty H Sharp

    Full Text Available Coral animals harbor diverse microorganisms in their tissues, including archaea, bacteria, viruses, and zooxanthellae. The extent to which coral-bacterial associations are specific and the mechanisms for their maintenance across generations in the environment are unknown. The high diversity of bacteria in adult coral colonies has made it challenging to identify species-specific patterns. Localization of bacteria in gametes and larvae of corals presents an opportunity for determining when bacterial-coral associations are initiated and whether they are dynamic throughout early development. This study focuses on the early onset of bacterial associations in the mass spawning corals Montastraea annularis, M. franksi, M. faveolata, Acropora palmata, A. cervicornis, Diploria strigosa, and A. humilis. The presence of bacteria and timing of bacterial colonization was evaluated in gametes, swimming planulae, and newly settled polyps by fluorescence in situ hybridization (FISH using general eubacterial probes and laser-scanning confocal microscopy. The coral species investigated in this study do not appear to transmit bacteria via their gametes, and bacteria are not detectable in or on the corals until after settlement and metamorphosis. This study suggests that mass-spawning corals do not acquire, or are not colonized by, detectable numbers of bacteria until after larval settlement and development of the juvenile polyp. This timing lays the groundwork for developing and testing new hypotheses regarding general regulatory mechanisms that control bacterial colonization and infection of corals, and how interactions among bacteria and juvenile polyps influence the structure of bacterial assemblages in corals.

  16. QTLs for Resistance to Major Rice Diseases Exacerbated by Global Warming: Brown Spot, Bacterial Seedling Rot, and Bacterial Grain Rot.

    Science.gov (United States)

    Mizobuchi, Ritsuko; Fukuoka, Shuichi; Tsushima, Seiya; Yano, Masahiro; Sato, Hiroyuki

    2016-12-01

    In rice (Oryza sativa L.), damage from diseases such as brown spot, caused by Bipolaris oryzae, and bacterial seedling rot and bacterial grain rot, caused by Burkholderia glumae, has increased under global warming because the optimal temperature ranges for growth of these pathogens are relatively high (around 30 °C). Therefore, the need for cultivars carrying genes for resistance to these diseases is increasing to ensure sustainable rice production. In contrast to the situation for other important rice diseases such as blast and bacterial blight, no genes for complete resistance to brown spot, bacterial seedling rot or bacterial grain rot have yet been discovered. Thus, rice breeders have to use partial resistance, which is largely influenced by environmental conditions. Recent progress in molecular genetics and improvement of evaluation methods for disease resistance have facilitated detection of quantitative trait loci (QTLs) associated with resistance. In this review, we summarize the results of worldwide screening for cultivars with resistance to brown spot, bacterial seedling rot and bacterial grain rot and we discuss the identification of QTLs conferring resistance to these diseases in order to provide useful information for rice breeding programs.

  17. QTLs for Resistance to Major Rice Diseases Exacerbated by Global Warming: Brown Spot, Bacterial Seedling Rot, and Bacterial Grain Rot.

    Science.gov (United States)

    Mizobuchi, Ritsuko; Fukuoka, Shuichi; Tsushima, Seiya; Yano, Masahiro; Sato, Hiroyuki

    2016-12-01

    In rice (Oryza sativa L.), damage from diseases such as brown spot, caused by Bipolaris oryzae, and bacterial seedling rot and bacterial grain rot, caused by Burkholderia glumae, has increased under global warming because the optimal temperature ranges for growth of these pathogens are relatively high (around 30 °C). Therefore, the need for cultivars carrying genes for resistance to these diseases is increasing to ensure sustainable rice production. In contrast to the situation for other important rice diseases such as blast and bacterial blight, no genes for complete resistance to brown spot, bacterial seedling rot or bacterial grain rot have yet been discovered. Thus, rice breeders have to use partial resistance, which is largely influenced by environmental conditions. Recent progress in molecular genetics and improvement of evaluation methods for disease resistance have facilitated detection of quantitative trait loci (QTLs) associated with resistance. In this review, we summarize the results of worldwide screening for cultivars with resistance to brown spot, bacterial seedling rot and bacterial grain rot and we discuss the identification of QTLs conferring resistance to these diseases in order to provide useful information for rice breeding programs. PMID:27178300

  18. [Small intestine bacterial overgrowth].

    Science.gov (United States)

    Leung Ki, E L; Roduit, J; Delarive, J; Guyot, J; Michetti, P; Dorta, G

    2010-01-27

    Small intestine bacterial overgrowth (SIBO) is a condition characterised by nutrient malabsorption and excessive bacteria in the small intestine. It typically presents with diarrhea, flatulence and a syndrome of malabsorption (steatorrhea, macrocytic anemia). However, it may be asymptomatic in the eldery. A high index of suspicion is necessary in order to differentiate SIBO from other similar presenting disorders such as coeliac disease, lactose intolerance or the irritable bowel syndrome. A search for predisposing factor is thus necessary. These factors may be anatomical (stenosis, blind loop), or functional (intestinal hypomotility, achlorydria). The hydrogen breath test is the most frequently used diagnostic test although it lacks standardisation. The treatment of SIBO consists of eliminating predisposing factors and broad-spectrum antibiotic therapy. PMID:20214190

  19. Studying bacterial multispecies biofilms

    DEFF Research Database (Denmark)

    Røder, Henriette Lyng; Sørensen, Søren Johannes; Burmølle, Mette

    2016-01-01

    The high prevalence and significance of multispecies biofilms have now been demonstrated in various bacterial habitats with medical, industrial, and ecological relevance. It is highly evident that several species of bacteria coexist and interact in biofilms, which highlights the need for evaluating...... the approaches used to study these complex communities. This review focuses on the establishment of multispecies biofilms in vitro, interspecies interactions in microhabitats, and how to select communities for evaluation. Studies have used different experimental approaches; here we evaluate the benefits...... and drawbacks of varying the degree of complexity. This review aims to facilitate multispecies biofilm research in order to expand the current limited knowledge on interspecies interactions. Recent technological advances have enabled total diversity analysis of highly complex and diverse microbial communities...

  20. Bacterial proteases and virulence

    DEFF Research Database (Denmark)

    Frees, Dorte; Brøndsted, Lone; Ingmer, Hanne

    2013-01-01

    Bacterial pathogens rely on proteolysis for variety of purposes during the infection process. In the cytosol, the main proteolytic players are the conserved Clp and Lon proteases that directly contribute to virulence through the timely degradation of virulence regulators and indirectly by providing...... tolerance to adverse conditions such as those experienced in the host. In the membrane, HtrA performs similar functions whereas the extracellular proteases, in close contact with host components, pave the way for spreading infections by degrading host matrix components or interfering with host cell...... signalling to short-circuit host cell processes. Common to both intra- and extracellular proteases is the tight control of their proteolytic activities. In general, substrate recognition by the intracellular proteases is highly selective which is, in part, attributed to the chaperone activity associated...

  1. 天津市2008年-2010年细菌性食物中毒实验检测及相关问题分析%Analysis of detection of bacterial food poisoning and probe on relational problem from 2008 to 2010 in Tianjin.

    Institute of Scientific and Technical Information of China (English)

    丁建清; 张文生; 孙美玲; 苟锦博

    2011-01-01

    Objective:To analyze 17 incidents of pathogenic bacterium cause of food poisoning and in Tianjin city during 2008 -2010 and understand the occurrence rule, in order to provide technical support for handling the food poisoning issues quickly. Methods: According to the bacterial food poisoning occurred in Tianjin during 2008 -2010, to analyze the pathogen diagnosed by laboratory. Results: In three years, a total of 17 incidents of bacterial food poisoning with 734 cases occurred and the quarter of third is peak of food poisoning accounting for 70.59% in Tianjin. The distribution site of food poisoning were public food services of students and enterorises, both accounting for 35.29% repectively and secondly is box_rice of fast food company accounting for 23.53%. Conclusion: The vibrio parahaemolyticus is the main pathogenic bacterium in bacterial food poisoning with the detection rate of 41.18% in total bacterial food poisoning incidents in Tianjin, which should be paid more attention by the government.%目的:了解天津市2008年-2010年17起细菌性食物中毒病原菌发生规律,为快速处置食物中毒事件提供技术支撑.方法:对天津市2008年-2010年发生的细菌性食物中毒经实验室确诊的病原进行分析.结果:天津市3年间共发生细菌性食物中17起,中毒人数734人.发生季节主要在第三季度(70.59%),发生场所主要以学生和企业中的集体食堂为主,分别为35.29%和35.29%,其次是快餐配送公司盒饭,为23.53%.结论:本市细菌性食物中毒主要以副溶血性弧菌为主要病原菌,检出率占整个事件的41.18%,应引起政府部门的高度关注.

  2. Contamination of healthcare workers' hands with bacterial spores.

    Science.gov (United States)

    Sasahara, Teppei; Ae, Ryusuke; Watanabe, Michiyo; Kimura, Yumiko; Yonekawa, Chikara; Hayashi, Shunji; Morisawa, Yuji

    2016-08-01

    Clostridium species and Bacillus spp. are spore-forming bacteria that cause hospital infections. The spores from these bacteria are transmitted from patient to patient via healthcare workers' hands. Although alcohol-based hand rubbing is an important hand hygiene practice, it is ineffective against bacterial spores. Therefore, healthcare workers should wash their hands with soap when they are contaminated with spores. However, the extent of health care worker hand contamination remains unclear. The aim of this study is to determine the level of bacterial spore contamination on healthcare workers' hands. The hands of 71 healthcare workers were evaluated for bacterial spore contamination. Spores attached to subject's hands were quantitatively examined after 9 working hours. The relationship between bacterial spore contamination and hand hygiene behaviors was also analyzed. Bacterial spores were detected on the hands of 54 subjects (76.1%). The mean number of spores detected was 468.3 CFU/hand (maximum: 3300 CFU/hand). Thirty-seven (52.1%) and 36 (50.7%) subjects were contaminated with Bacillus subtilis and Bacillus cereus, respectively. Nineteen subjects (26.8%) were contaminated with both Bacillus species. Clostridium difficile was detected on only one subject's hands. There was a significant negative correlation between the hand contamination level and the frequency of handwashing (r = -0.44, P time since last handwashing (r = 0.34, P handwashing during daily patient care. PMID:27236515

  3. The Implications of Serum Procalcitonion(PCT) and Blood Normal(BR) Detection in Patients with Bacterial Pneumonia%血清降钙素原和血常规测定对细菌性肺炎的指导意义

    Institute of Scientific and Technical Information of China (English)

    颜鲲; 徐慧兰

    2014-01-01

    Objective To evaluate the implications of the detection of Serum Procalcitonion (PCT) and BR in patients with Bacterial Pneumonia,and provide theoretical reference for diagnosis and treatment of Bacterial Pneumonia. Methods 64 samples were col ected from patients with Bacterial Pneumonia in respiratory department、ICU and emergency department from January to November 2011,and compared with 32 healthy people .PCT and BR were measured. The PCT level was determined by Brahms PCT-Q method. Results The sensitivities of PCT and BR were 78 %and 63 %,respectively with the sepcificities being 97 %and 70 %.The serum PCT levels of Bacterial Pneumonia group were higher than the healthy group, compared the difference was significant (P<0.05). The serum PCT levels of Bacterial Pneumonia group before using antibiotics were higher than that after effective therapy, compared the difference was significant (P<0.05). Conclusions The serum PCT has diagnostic value for the Bacterial Pneumonia, and it is a useful index to assess the clinical efficacy in patients using antibiotics. It is worthy of clinical application.%目的:探讨血清降钙素原(PCT)和血常规(BR)在细菌性肺炎诊断中的应用价值,旨在为细菌性肺炎的诊治提供理论参考。方法选取中南大学湘雅三医院2011年1月至11月在呼吸、急诊、ICU 住院的细菌性肺炎患者64例,同期健康对照组32例,血清 PCT 采用 Brahms 快速半定量法(PCT-Q)测定,同期检测血常规。结果细菌性肺炎组中,PCT、白细胞计数对诊断的敏感性分别为78%和63%,特异性分别为97%和70%,细菌性肺炎组较健康对照组 PCT 水平显著增高,相比较有显著性差异(P <0.05)。细菌性肺炎组抗生素治疗前和好转后,血清 PCT 水平显著下降,相比较有显著性差异(P <0.05)。结论血清 PCT 的测定对细菌性肺炎有鉴别诊断价值,特别是可反应抗生素治疗效果,值得临床推广应用。

  4. The aerobic bacterial flora of the nasal cavity in healthy Anatolian water buffalo calves

    OpenAIRE

    Şeker, Esra; Yardimci, Hakan

    2010-01-01

    Nasal swab samples from clinically healthy Anatolian water buffalo calves, breeding in Afyonkarahisar provinceof Turkey, were collected to determine the bacterial microflora of their nasal mucosa. A total of 160 samples were examined and 165bacterial isolates were identified by using standard microbiological and biochemical methods. Ninety-seven isolates were detected toGram positive bacteria (58.8%) and 68 isolates to Gram negative bacteria (41.2%). Ten bacterial genera including Staphylococ...

  5. Bacterial diversity in persistent periapical lesions on root-filled teeth

    OpenAIRE

    Handal, Trude; Caugant, Dominique A; Olsen, Ingar; Sunde, Pia T.

    2009-01-01

    Background: The purpose of this study was to analyze the bacterial diversity in persistent apical lesions on root-filled teeth by using culture-independent molecular methods. Design: Twenty surgically removed apical lesions from therapy-resistant teeth were examined for the presence of bacterial DNA using PCR targeting the 16s ribosomal RNA gene, followed by cloning and sequencing. Results: Bacterial DNA was detected in 17 of the 20 samples (85%). A total of 236 clones were analyzed. Seven di...

  6. Bacterial Protein-Tyrosine Kinases

    DEFF Research Database (Denmark)

    Shi, Lei; Kobir, Ahasanul; Jers, Carsten;

    2010-01-01

    in exopolysaccharide production, virulence, DNA metabolism, stress response and other key functions of the bacterial cell. BY-kinases act through autophosphorylation (mainly in exopolysaccharide production) and phosphorylation of other proteins, which have in most cases been shown to be activated by tyrosine......Bacteria and Eukarya share essentially the same family of protein-serine/threonine kinases, also known as the Hanks-type kinases. However, when it comes to protein-tyrosine phosphorylation, bacteria seem to have gone their own way. Bacterial protein-tyrosine kinases (BY-kinases) are bacterial...... and highlighted their importance in bacterial physiology. Having no orthologues in Eukarya, BY-kinases are receiving a growing attention from the biomedical field, since they represent a particularly promising target for anti-bacterial drug design....

  7. Molecular approaches for bacterial azoreductases

    Directory of Open Access Journals (Sweden)

    Montira Leelakriangsak

    2013-12-01

    Full Text Available Azo dyes are the dominant types of synthetic dyes, widely used in textiles, foods, leather, printing, tattooing, cosmetics, and pharmaceutical industries. Many microorganisms are able to decolorize azo dyes, and there is increasing interest in biological waste treatment methods. Bacterial azoreductases can cleave azo linkages (-N=N- in azo dyes, forming aromatic amines. This review mainly focuses on employing molecular approaches, including gene manipulation and recombinant strains, to study bacterial azoreductases. The construction of the recombinant protein by cloning and the overexpression of azoreductase is described. The mechanisms and function of bacterial azoreductases can be studied by other molecular techniques discussed in this review, such as RT-PCR, southern blot analysis, western blot analysis, zymography, and muta-genesis in order to understand bacterial azoreductase properties, function and application. In addition, understanding the regulation of azoreductase gene expression will lead to the systematic use of gene manipulation in bacterial strains for new strategies in future waste remediation technologies.

  8. Carbon nanotubes as in vivo bacterial probes

    Science.gov (United States)

    Bardhan, Neelkanth M.; Ghosh, Debadyuti; Belcher, Angela M.

    2014-09-01

    With the rise in antibiotic-resistant infections, non-invasive sensing of infectious diseases is increasingly important. Optical imaging, although safer and simpler, is less developed than other modalities such as radioimaging, due to low availability of target-specific molecular probes. Here we report carbon nanotubes (SWNTs) as bacterial probes for fluorescence imaging of pathogenic infections. We demonstrate that SWNTs functionalized using M13 bacteriophage (M13-SWNT) can distinguish between F‧-positive and F‧-negative bacterial strains. Moreover, through one-step modification, we attach an anti-bacterial antibody on M13-SWNT, making it easily tunable for sensing specific F‧-negative bacteria. We illustrate detection of Staphylococcus aureus intramuscular infections, with ~3.4 × enhancement in fluorescence intensity over background. SWNT imaging presents lower signal spread ~0.08 × and higher signal amplification ~1.4 × , compared with conventional dyes. We show the probe offers greater ~5.7 × enhancement in imaging of S. aureus infective endocarditis. These biologically functionalized, aqueous-dispersed, actively targeted, modularly tunable SWNT probes offer new avenues for exploration of deeply buried infections.

  9. C-反应蛋白检测在小儿细菌性肺炎及支原体肺炎中的应用%Detection of C-reactive protein applied in diagnosis of children with bacterial pneumonia and mycoplasma pneumonia

    Institute of Scientific and Technical Information of China (English)

    贺箭飞

    2012-01-01

    目的 对比分析C反应蛋白检测在小儿细菌性肺炎和支原体肺炎的诊断价值.方法 选取148例肺炎患儿及同期进行健康体检的150例健康小儿作为研究对象,对所有受试者进行C-反应蛋白、肺炎支原体、血常规检测,对148例肺炎患儿治疗前后进行C-反应蛋白水平检测,比较健康小儿、支原体肺炎患儿、细菌性肺炎患儿的C-反应蛋白水平,比较细菌性肺炎患儿与支原体肺炎患儿治疗前后的C-反应蛋白水平,比较C-反应蛋白对不同类型肺炎患儿的阳性检测率,综合评价C-反应蛋白在肺炎患儿诊断鉴别中的价值.结果 健康患儿、肺炎支原体患儿、细菌性肺炎患儿的C反应蛋白分别为(3.58±0.79)、(14.82±3.69)、(68.54±28.31)mg/L;组间比较,肺炎组患儿明显高于健康组患儿(P<0.05),而细菌性肺炎组患儿明显高于支原体肺炎组患儿(P<0.05);细菌性肺炎患儿C-反应蛋白的阳性率为93.3%、支原体肺炎患儿为45.6%,患儿经治疗后,C-反应蛋白均明显下降,上述指标组间比较及治疗前后比较,差异均有统计学意义(P<0.05).结论 C-反应蛋白检测可作为鉴别细菌性肺炎和支原体肺炎的有效手段,有助于临床医师采取相应的治疗方法及早治疗患儿,以免耽误病情.%OBJECTIVE To compare and analyze the C-reactive protein detection for the diagnosis of the children with bacterial pneumonia and mycoplasma pneumonia. METHODS A total of 148 children with pneumonia and 150 healthy children were chosen as the research subjects. All subjects were taken with the C-reactive protein, Mycoplasma pneumoniae. and blood testing. The levels of C-reactive protein of 148 cases of pneumonia children were tested before and after the treatment. The C-reactive protein levels of the healthy children, the children with mycoplasma pneumonia, and the children with bacterial pneumonia were compared. The C-reactive protein levels of the children

  10. Comparison of BD Bactec Plus Blood Culture Media to VersaTREK Redox Blood Culture Media for Detection of Bacterial Pathogens in Simulated Adult Blood Cultures Containing Therapeutic Concentrations of Antibiotics▿

    OpenAIRE

    Miller, Nancy S.; Rogan, Dagmar; Orr, Beverley L.; Whitney, Dana

    2011-01-01

    Antibiotic neutralization in blood culture media from two automated systems was evaluated by measuring the recovery of organisms and times to detection in simulated cultures. Overall, BD Bactec Plus media (Bactec FX system) outperformed TREK 80 ml Redox media (VersaTREK system), although results suggest a relative rather than an absolute increased rate of recovery for the Bactec media.

  11. Comparison of Established Diagnostic Methodologies and a Novel Bacterial smpB Real-Time PCR Assay for Specific Detection of Haemophilus influenzae Isolates Associated with Respiratory Tract Infections

    OpenAIRE

    Reddington, Kate; Schwenk, Stefan; Tuite, Nina; Platt, Gareth; Davar, Danesh; Coughlan, Helena; Personne, Yoann; Gant, Vanya; Enne, Virve I.; Zumla, Alimuddin; Barry, Thomas

    2015-01-01

    Haemophilus influenzae is a significant causative agent of respiratory tract infections (RTI) worldwide. The development of a rapid H. influenzae diagnostic assay that would allow for the implementation of infection control measures and also improve antimicrobial stewardship for patients is required. A number of nucleic acid diagnostics approaches that detect H. influenzae in RTIs have been described in the literature; however, there are reported specificity and sensitivity limitations for th...

  12. Positioning of bacterial chemoreceptors.

    Science.gov (United States)

    Jones, Christopher W; Armitage, Judith P

    2015-05-01

    For optimum growth, bacteria must adapt to their environment, and one way that many species do this is by moving towards favourable conditions. To do so requires mechanisms to both physically drive movement and provide directionality to this movement. The pathways that control this directionality comprise chemoreceptors, which, along with an adaptor protein (CheW) and kinase (CheA), form large hexagonal arrays. These arrays can be formed around transmembrane receptors, resulting in arrays embedded in the inner membrane, or they can comprise soluble receptors, forming arrays in the cytoplasm. Across bacterial species, chemoreceptor arrays (both transmembrane and soluble) are localised to a variety of positions within the cell; some species with multiple arrays demonstrate this variety within individual cells. In many cases, the positioning pattern of the arrays is linked to the need for segregation of arrays between daughter cells on division, ensuring the production of chemotactically competent progeny. Multiple mechanisms have evolved to drive this segregation, including stochastic self-assembly, cellular landmarks, and the utilisation of ParA homologues. The variety of mechanisms highlights the importance of chemotaxis to motile species.

  13. Evolution of Bacterial Suicide

    Science.gov (United States)

    Tchernookov, Martin; Nemenman, Ilya

    2013-03-01

    While active, controlled cellular suicide (autolysis) in bacteria is commonly observed, it has been hard to argue that autolysis can be beneficial to an individual who commits it. We propose a theoretical model that predicts that bacterial autolysis is evolutionarily advantageous to an individualand would fixate in physically structured environments for stationary phase colonies. We perform spatially resolved agent-based simulations of the model, which predict that lower mixing in the environment results in fixation of a higher autolysis rate from a single mutated cell, regardless of the colony's genetic diversity. We argue that quorum sensing will fixate as well, even if initially rare, if it is coupled to controlling the autolysis rate. The model does not predict a strong additional competitive advantage for cells where autolysis is controlled by quorum sensing systems that distinguish self from nonself. These predictions are broadly supported by recent experimental results in B. subtilisand S. pneumoniae. Research partially supported by the James S McDonnell Foundation grant No. 220020321 and by HFSP grant No. RGY0084/2011.

  14. Electromagnetism of Bacterial Growth

    Science.gov (United States)

    Ainiwaer, Ailiyasi

    2011-10-01

    There has been increasing concern from the public about personal health due to the significant rise in the daily use of electrical devices such as cell phones, radios, computers, GPS, video games and television. All of these devices create electromagnetic (EM) fields, which are simply magnetic and electric fields surrounding the appliances that simultaneously affect the human bio-system. Although these can affect the human system, obstacles can easily shield or weaken the electrical fields; however, magnetic fields cannot be weakened and can pass through walls, human bodies and most other objects. The present study was conducted to examine the possible effects of bacteria when exposed to magnetic fields. The results indicate that a strong causal relationship is not clear, since different magnetic fields affect the bacteria differently, with some causing an increase in bacterial cells, and others causing a decrease in the same cells. This phenomenon has yet to be explained, but the current study attempts to offer a mathematical explanation for this occurrence. The researchers added cultures to the magnetic fields to examine any effects to ion transportation. Researchers discovered ions such as potassium and sodium are affected by the magnetic field. A formula is presented in the analysis section to explain this effect.

  15. Clinical value of application high sensitive C reactive protein and white blood cell detection on bacterial infection diseases in pediatric department%超敏C反应蛋白和白细胞检测在儿科细菌感染性疾病中的临床应用价值

    Institute of Scientific and Technical Information of China (English)

    孟君; 程旭; 解辉

    2015-01-01

    Objective:To investigate the clinical value of application high sensitive C reactive protein and white blood cell detection on bacterial infection diseases in pediatric department. Methods:20 children with bacterial infection were selected as the research group,and another 20 healthy children as the control group.All of those 40 children were extracted anticoagulant venous blood in the early morning to detection of routine blood test and CRP.Results:The positive rate of CRP in the research group was 90%,while in the control group it was 0,and the difference was statistically significant between the two groups(P<0.05). The positive rate of WBC in children of the research group was 75%,and the positive rate of NEC was 80%.Conclusion:Detection of white blood cells combined with C-reactive protein is helpful in the early differential diagnosis of pediatric infectious disease.%目的:探讨超敏C反应蛋白(hs-CRP)和白细胞检测在儿科细菌感染性疾病中的临床应用价值。方法:收治细菌感染儿童20例作为研讨组和同期健康体检小儿20名作为对照组,所有患儿均于清晨抽取静脉抗凝血做血常规和hs-CRP检测。结果:研讨组患儿hs-CRP阳性率90%,对照组hs-CRP阳性率0,两组比较差异有统计学意义(P<0.05)。研讨组患儿WBC阳性率75%,NEC阳性率80%。结论:联合检测白细胞和hs-CRP有助于小儿感染性疾病的早期鉴别诊断。

  16. Bacterial Communities: Interactions to Scale

    Science.gov (United States)

    Stubbendieck, Reed M.; Vargas-Bautista, Carol; Straight, Paul D.

    2016-01-01

    In the environment, bacteria live in complex multispecies communities. These communities span in scale from small, multicellular aggregates to billions or trillions of cells within the gastrointestinal tract of animals. The dynamics of bacterial communities are determined by pairwise interactions that occur between different species in the community. Though interactions occur between a few cells at a time, the outcomes of these interchanges have ramifications that ripple through many orders of magnitude, and ultimately affect the macroscopic world including the health of host organisms. In this review we cover how bacterial competition influences the structures of bacterial communities. We also emphasize methods and insights garnered from culture-dependent pairwise interaction studies, metagenomic analyses, and modeling experiments. Finally, we argue that the integration of multiple approaches will be instrumental to future understanding of the underlying dynamics of bacterial communities. PMID:27551280

  17. Bacterial Communities: Interactions to Scale

    Directory of Open Access Journals (Sweden)

    Reed M. Stubbendieck

    2016-08-01

    Full Text Available In the environment, bacteria live in complex multispecies communities. These communities span in scale from small, multicellular aggregates to billions or trillions of cells within the gastrointestinal tract of animals. The dynamics of bacterial communities are determined by pairwise interactions that occur between different species in the community. Though interactions occur between a few cells at a time, the outcomes of these interchanges have ramifications that ripple through many orders of magnitude, and ultimately affect the macroscopic world including the health of host organisms. In this review we cover how bacterial competition influences the structures of bacterial communities. We also emphasize methods and insights garnered from culture-dependent pairwise interaction studies, metagenomic analyses, and modeling experiments. Finally, we argue that the integration of multiple approaches will be instrumental to future understanding of the underlying dynamics of bacterial communities.

  18. Meningitis bacteriana Bacterial meningitis

    Directory of Open Access Journals (Sweden)

    Ana Teresa Alvarado Guevara

    2006-03-01

    causales son virales lo cual conlleva a las diferentes sub-clasificaciones. También en ciertos casos puede ser ocasionada por hongos, bacterias atípicas, micobacterias y parásitos.In Costa Rica the bacterial meningitis had turn into a high-priority subject in which to monitoring epidemiologist. It had been talked about in the last months, to dice an increase in the attention is published of this subject, due to this phenomenon it becomes necessary to make a revision of topic. Meningitis is an inflammation of leptomeninges and colonization of the subarachnoid cerebrospinal fluid (LCR due to different agents, which produces meningeal symptoms (ex. migraine, neck rigidity, and photophobia and pleocytosis in LCR. De pending on the variables to take into account is possible to group it in different classifications, taking into account the time of evolution are possible to be divided in acute or chronic, to first with few hours or days of beginning of the symptoms, whereas the chronicle also presents a silence course but of the disease of approximately 4 weeks of instauration. There is a difference according to its etiologic agent; they can be infectious and non-infectious. Examples of common non-infectious causes include medications (ex, nonsteroidal anti-inflammatory drugs, and antibiotics and carcinomatosis. A classification exists as well according to the causal agent. The acute bacterial meningitis remarks a bacterial origin of the syndrome, which characterizes by the by an acute onset of meningeal symptoms and neutrophilic pleocytosis. Each one of the bacteriological agents, parasitic or fungus finishes by characterizing the different presentations of the clinical features (ex, meningocóccica meningitis, Cryptococcus meningitis. Finally, there is also the aseptic meningitis, denominated in this form because it’s nonpyogenic cellular response caused by many types of agents. The patients show an acute beginning of symptoms, fever and lymphocytic pleocytosis. After

  19. Bacterial Culture of Neonatal Sepsis

    OpenAIRE

    AH Movahedian; R Moniri; Z Mosayebi

    2006-01-01

    Neonatal bacterial sepsis is one of the major cause of morbidity and mortality in neonates. This retrospective study was performed to determine the incidence of bacterial sepsis with focus on Gram negative organisms in neonates admitted at Beheshti Hospital in Kashan, during a 3-yr period, from September 2002 to September 2005. Blood culture was performed on all neonates with risk factors or signs of suggestive sepsis. Blood samples were cultured using brain heart infusion (BHI) broth accordi...

  20. Mast cells in bacterial infections

    OpenAIRE

    Rönnberg, Elin

    2014-01-01

    Mast cells are implicated in immunity towards bacterial infection, but the molecular mechanisms by which mast cells contribute to the host response are only partially understood. Previous studies have examined how mast cells react to purified bacterial cell wall components, such as peptidoglycan and lipopolysaccharide. To investigate how mast cells react to live bacteria we co-cultured mast cells and the gram-positive bacteria Streptococcus equi (S. equi) and Staphylococcus aureus (S. aureus)...

  1. Bacterial Alkaloids Prevent Amoebal Predation.

    Science.gov (United States)

    Klapper, Martin; Götze, Sebastian; Barnett, Robert; Willing, Karsten; Stallforth, Pierre

    2016-07-25

    Bacterial defense mechanisms have evolved to protect bacteria against predation by nematodes, predatory bacteria, or amoebae. We identified novel bacterial alkaloids (pyreudiones A-D) that protect the producer, Pseudomonas fluorescens HKI0770, against amoebal predation. Isolation, structure elucidation, total synthesis, and a proposed biosynthetic pathway for these structures are presented. The generation of P. fluorescens gene-deletion mutants unable to produce pyreudiones rendered the bacterium edible to a variety of soil-dwelling amoebae. PMID:27294402

  2. Bacterial cellulose/boehmite composites

    International Nuclear Information System (INIS)

    Composites based on bacterial cellulose membranes and boehmite were obtained. SEM results indicate that the bacterial cellulose (BC) membranes are totally covered by boehmite and obtained XRD patterns suggest structural changes due to this boehmite addition. Thermal stability is accessed through TG curves and is dependent on boehmite content. Transparency is high comparing to pure BC as can be seen through UV-vis absorption spectroscopy. (author)

  3. Correlation Between the Clinical Diagnosis of Bacterial Vaginosis and the Results of a Proline Aminopeptidase Assay

    Directory of Open Access Journals (Sweden)

    George H. Nelson

    1994-01-01

    Full Text Available Objective: The object of this study was to develop a simple and inexpensive test for detection of bacterial vaginosis (BV in pregnant patients and to test its accuracy in a clinic population.

  4. Elongation factor P mediates a novel post-transcriptional regulatory pathway critical for bacterial virulence

    DEFF Research Database (Denmark)

    Zou, S Betty; Roy, Hervé; Ibba, Michael;

    2012-01-01

    Bacterial pathogens detect and integrate multiple environmental signals to coordinate appropriate changes in gene expression including the selective expression of virulence factors, changes to metabolism and the activation of stress response systems. Mutations that abolish the ability...

  5. Contamination of healthcare workers' hands with bacterial spores.

    Science.gov (United States)

    Sasahara, Teppei; Ae, Ryusuke; Watanabe, Michiyo; Kimura, Yumiko; Yonekawa, Chikara; Hayashi, Shunji; Morisawa, Yuji

    2016-08-01

    Clostridium species and Bacillus spp. are spore-forming bacteria that cause hospital infections. The spores from these bacteria are transmitted from patient to patient via healthcare workers' hands. Although alcohol-based hand rubbing is an important hand hygiene practice, it is ineffective against bacterial spores. Therefore, healthcare workers should wash their hands with soap when they are contaminated with spores. However, the extent of health care worker hand contamination remains unclear. The aim of this study is to determine the level of bacterial spore contamination on healthcare workers' hands. The hands of 71 healthcare workers were evaluated for bacterial spore contamination. Spores attached to subject's hands were quantitatively examined after 9 working hours. The relationship between bacterial spore contamination and hand hygiene behaviors was also analyzed. Bacterial spores were detected on the hands of 54 subjects (76.1%). The mean number of spores detected was 468.3 CFU/hand (maximum: 3300 CFU/hand). Thirty-seven (52.1%) and 36 (50.7%) subjects were contaminated with Bacillus subtilis and Bacillus cereus, respectively. Nineteen subjects (26.8%) were contaminated with both Bacillus species. Clostridium difficile was detected on only one subject's hands. There was a significant negative correlation between the hand contamination level and the frequency of handwashing (r = -0.44, P contamination level and the elapsed time since last handwashing (r = 0.34, P contaminated with bacterial spores due to insufficient handwashing during daily patient care.

  6. Bacterial migration through punctured surgical gloves under real surgical conditions

    Directory of Open Access Journals (Sweden)

    Heidecke Claus-Dieter

    2010-07-01

    Full Text Available Abstract Background The aim of this study was to confirm recent results from a previous study focussing on the development of a method to measure the bacterial translocation through puncture holes in surgical gloves under real surgical conditions. Methods An established method was applied to detect bacterial migration from the operating site through the punctured glove. Biogel™ double-gloving surgical gloves were used during visceral surgeries over a 6-month period. A modified Gaschen-bag method was used to retrieve organisms from the inner glove, and thus-obtained bacteria were compared with micro-organisms detected by an intra-operative swab. Results In 20 consecutive procedures, 194 gloves (98 outer gloves, 96 inner gloves were examined. The rate of micro-perforations of the outer surgical glove was 10% with a median wearing time of 100 minutes (range: 20-175 minutes. Perforations occurred in 81% on the non-dominant hand, with the index finger most frequently (25% punctured. In six cases, bacterial migration could be demonstrated microbiologically. In 5% (5/98 of outer gloves and in 1% (1/96 of the inner gloves, bacterial migration through micro-perforations was observed. For gloves with detected micro-perforations (n = 10 outer layers, the calculated migration was 50% (n = 5. The minimum wearing time was 62 minutes, with a calculated median wearing time of 71 minutes. Conclusions This study confirms previous results that bacterial migration through unnoticed micro-perforations in surgical gloves does occur under real practical surgical conditions. Undetected perforation of surgical gloves occurs frequently. Bacterial migration from the patient through micro-perforations on the hand of surgeons was confirmed, limiting the protective barrier function of gloves if worn over longer periods.

  7. Comparison of Established Diagnostic Methodologies and a Novel Bacterial smpB Real-Time PCR Assay for Specific Detection of Haemophilus influenzae Isolates Associated with Respiratory Tract Infections.

    Science.gov (United States)

    Reddington, Kate; Schwenk, Stefan; Tuite, Nina; Platt, Gareth; Davar, Danesh; Coughlan, Helena; Personne, Yoann; Gant, Vanya; Enne, Virve I; Zumla, Alimuddin; Barry, Thomas

    2015-09-01

    Haemophilus influenzae is a significant causative agent of respiratory tract infections (RTI) worldwide. The development of a rapid H. influenzae diagnostic assay that would allow for the implementation of infection control measures and also improve antimicrobial stewardship for patients is required. A number of nucleic acid diagnostics approaches that detect H. influenzae in RTIs have been described in the literature; however, there are reported specificity and sensitivity limitations for these assays. In this study, a novel real-time PCR diagnostic assay targeting the smpB gene was designed to detect all serogroups of H. influenzae. The assay was validated using a panel of well-characterized Haemophilus spp. Subsequently, 44 Haemophilus clinical isolates were collected, and 36 isolates were identified as H. influenzae using a gold standard methodology that combined the results of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and a fucK diagnostic assay. Using the novel smpB diagnostic assay, 100% concordance was observed with the gold standard, demonstrating a sensitivity of 100% (95% confidence interval [CI], 90.26% to 100.00%) and a specificity of 100% (95% CI, 63.06% to 100.00%) when used on clinical isolates. To demonstrate the clinical utility of the diagnostic assay presented, a panel of lower RTI samples (n = 98) were blindly tested with the gold standard and smpB diagnostic assays. The results generated were concordant for 94/98 samples tested, demonstrating a sensitivity of 90.91% (95% CI, 78.33% to 97.47%) and a specificity of 100% (95% CI, 93.40% to 100.00%) for the novel smpB assay when used directly on respiratory specimens. PMID:26109443

  8. 动态浊度法定量测定黄芪注射液中细菌内毒素的含量%Detection of Bacterial Endotoxin in Huangqi Injection by the Method of Kinetic Turbidimetric Limulus Test

    Institute of Scientific and Technical Information of China (English)

    卢文斌

    2012-01-01

    OBJECTIVE To detect the quantity of endotoxin in huangqi injection by the method of kinetic turbidimetric limulus test. METHODS The kinetic turbidimetric limulus test was applied to detect the quantity of endotoxin in several samples. The standard endotoxin working curve was set up and the interference test was studied to range the effective concentrations of sample. RESULTS Dilution ratio of Huangqi injection at 1 : 5 show no inference in the test. The endotoxin recovery rate was more than 50% and less than 200%. The endotoxin level in samples could be quantified exactly, and the results were accorded with the results obtained by gel-clot technique assay. CONCLUSION The kinetic turbidimetric limulus test can be used to quantitate the endotoxin level in huangqi injection.%目的 应用动态浊度法尝试验定量测定黄芪注射液中的细菌内毒素含量.方法 通过干扰试验确定样品检测浓度,并建立标准曲线对不同的样品进行细菌内毒素的定量测定.结果 样品用BET水制成1∶5稀释液,对鲎试验检查无干扰,细菌内毒素回收率在50% ~ 200%之间.样品中的内毒素含量可定量测定,检测结果与凝胶法检测的结果有一定的相关性.结论 动态浊度法可用于黄芪注射液中细菌内毒素定量检测.

  9. Bacterial Biosensors for Measuring Availability of Environmental Pollutants

    Directory of Open Access Journals (Sweden)

    Jan Roelof van der Meer

    2008-07-01

    Full Text Available Traditionally, pollution risk assessment is based on the measurement of a pollutant’s total concentration in a sample. The toxicity of a given pollutant in the environment, however, is tightly linked to its bioavailability, which may differ significantly from the total amount. Physico-chemical and biological parameters strongly influence pollutant fate in terms of leaching, sequestration and biodegradation. Bacterial sensorreporters, which consist of living micro-organisms genetically engineered to produce specific output in response to target chemicals, offer an interesting alternative to monitoring approaches. Bacterial sensor-reporters detect bioavailable and/or bioaccessible compound fractions in samples. Currently, a variety of environmental pollutants can be targeted by specific biosensor-reporters. Although most of such strains are still confined to the lab, several recent reports have demonstrated utility of bacterial sensing-reporting in the field, with method detection limits in the nanomolar range. This review illustrates the general design principles for bacterial sensor-reporters, presents an overview of the existing biosensor-reporter strains with emphasis on organic compound detection. A specific focus throughout is on the concepts of bioavailability and bioaccessibility, and how bacteria-based sensing-reporting systems can help to improve our basic understanding of the different processes at work.

  10. Relationship between Intrauterine Bacterial Infection and Early Embryonic Developmental Arrest

    Institute of Scientific and Technical Information of China (English)

    Shao-Fei Yan; Xin-Yan Liu; Yun-Fei Cheng; Zhi-Yi Li; Jie Ou; Wei Wang; Feng-Qin Li

    2016-01-01

    Background:Early embryonic developmental arrest is the most commonly understudied adverse outcome of pregnancy.The relevance of intrauterine infection to spontaneous embryonic death is rarely studied and remains unclear.This study aimed to investigate the relationship between intrauterine bacterial infection and early embryonic developmental arrest.Methods:Embryonic chorion tissue and uterine swabs for bacterial detection were obtained from 33 patients who underwent artificial abortion (control group) and from 45 patients who displayed early embryonic developmental arrest (trial group).Results:Intrauterine bacterial infection was discovered in both groups.The infection rate was 24.44% (11/45) in the early embryonic developmental arrest group and 9.09% (3/33) in the artificial abortion group.Classification analysis revealed that the highest detection rate for Micrococcus luteus in the early embryonic developmental arrest group was 13.33% (6/45),and none was detected in the artificial abortion group.M.luteus infection was significantly different between the groups (P < 0.05 as shown by Fisher's exact test).In addition,no correlation was found between intrauterine bacterial infection and history of early embryonic developmental arrest.Conclusions:M.luteus infection is related to early embryonic developmental arrest and might be one of its causative factors.

  11. Differentiation of bacterial colonies and temporal growth patterns using hyperspectral imaging

    Science.gov (United States)

    Mehrübeoglu, Mehrube; Buck, Gregory W.; Livingston, Daniel W.

    2014-09-01

    Detection and identification of bacteria are important for health and safety. Hyperspectral imaging offers the potential to capture unique spectral patterns and spatial information from bacteria which can then be used to detect and differentiate bacterial species. Here, hyperspectral imaging has been used to characterize different bacterial colonies and investigate their growth over time. Six bacterial species (Pseudomonas fluorescens, Escherichia coli, Serratia marcescens, Salmonella enterica, Staphylococcus aureus, Enterobacter aerogenes) were grown on tryptic soy agar plates. Hyperspectral data were acquired immediately after, 24 hours after, and 96 hours after incubation. Spectral signatures from bacterial colonies demonstrated repeatable measurements for five out of six species. Spatial variations as well as changes in spectral signatures were observed across temporal measurements within and among species at multiple wavelengths due to strengthening or weakening reflectance signals from growing bacterial colonies based on their pigmentation. Between-class differences and within-class similarities were the most prominent in hyperspectral data collected 96 hours after incubation.

  12. Bacterial danger sensing.

    Science.gov (United States)

    LeRoux, Michele; Peterson, S Brook; Mougous, Joseph D

    2015-11-20

    Here we propose that bacteria detect and respond to threats posed by other bacteria via an innate immune-like process that we term danger sensing. We find support for this contention by reexamining existing literature from the perspective that intermicrobial antagonism, not opportunistic pathogenesis, is the major evolutionary force shaping the defensive behaviors of most bacteria. We conclude that many bacteria possess danger sensing pathways composed of a danger signal receptor and corresponding signal transduction mechanism that regulate pathways important for survival in the presence of the perceived competitor.

  13. 细菌16 S核糖体RNA基因检测杰氏棒状杆菌一株%Identification of corynebacterium jeikeium by detection of bacterial 16s ribosomal RNA gene

    Institute of Scientific and Technical Information of China (English)

    崔颖鹏; 黄朱亮

    2015-01-01

    Objective To detect clinical strain by amplifying 16S ribosomal RNA( 16S rRNA) gene with polymerase chain reaction ( PCR) method. Methods 16S rRNA gene was amplifyied by universal primers P1,P2 with polymerase chain reaction,and the polymerase chain reaction products were sequenced to achieve the DNA sequences. Results PCR products were about 1 465bp, and the PCR sequences were blasted in NCBI web to achieve the proper strain name,with the use of this method,the unkown gram⁃positive bacilli strain was identified as corynebacterium jeikeium strain, ATCC25923 was identified as a strain of staphylococcus aureus and negative control was also specific.Conclusion 16S rRNA gene detection can be used as strain identification,and especially for some less common clinical strains.%目的:探讨通过16S核糖体RNA(16S rRNA )基因测序的方法用于临床菌株鉴定。方法以细菌16S rRNA基因为靶序列,采用细菌的通用引物P1、P2进行PCR扩增,同时送到测序公司测序从而达到鉴定。结果待测菌株及ATCC25923阳性对照通过PCR得到的扩增片段为1465bp左右,待测菌株经测序比对鉴定为一株杰氏棒状杆菌,阳性质控ATCC25923鉴定为一株金黄的葡萄球菌,阴性对照未出现任何结果。结论通过PCR检测细菌16srRNA基因可以应用于临床菌株的鉴定,并且适用一些难以鉴定的细菌。

  14. The Human Vaginal Bacterial Biota and Bacterial Vaginosis

    Directory of Open Access Journals (Sweden)

    Sujatha Srinivasan

    2008-01-01

    Full Text Available The bacterial biota of the human vagina can have a profound impact on the health of women and their neonates. Changes in the vaginal microbiota have been associated with several adverse health outcomes including premature birth, pelvic inflammatory disease, and acquisition of HIV infection. Cultivation-independent molecular methods have provided new insights regarding bacterial diversity in this important niche, particularly in women with the common condition bacterial vaginosis (BV. PCR methods have shown that women with BV have complex communities of vaginal bacteria that include many fastidious species, particularly from the phyla Bacteroidetes and Actinobacteria. Healthy women are mostly colonized with lactobacilli such as Lactobacillus crispatus, Lactobacillus jensenii, and Lactobacillus iners, though a variety of other bacteria may be present. The microbiology of BV is heterogeneous. The presence of Gardnerella vaginalis and Atopobium vaginae coating the vaginal epithelium in some subjects with BV suggests that biofilms may contribute to this condition.

  15. Bacterial tactic responses.

    Science.gov (United States)

    Armitage, J P

    1999-01-01

    Many, if not most, bacterial species swim. The synthesis and operation of the flagellum, the most complex organelle of a bacterium, takes a significant percentage of cellular energy, particularly in the nutrient limited environments in which many motile species are found. It is obvious that motility accords cells a survival advantage over non-motile mutants under normal, poorly mixed conditions and is an important determinant in the development of many associations between bacteria and other organisms, whether as pathogens or symbionts and in colonization of niches and the development of biofilms. This survival advantage is the result of sensory control of swimming behaviour. Although too small to sense a gradient along the length of the cell, and unable to swim great distances because of buffetting by Brownian motion and the curvature resulting from a rotating flagellum, bacteria can bias their random swimming direction towards a more favourable environment. The favourable environment will vary from species to species and there is now evidence that in many species this can change depending on the current physiological growth state of the cell. In general, bacteria sense changes in a range of nutrients and toxins, compounds altering electron transport, acceptors or donors into the electron transport chain, pH, temperature and even the magnetic field of the Earth. The sensory signals are balanced, and may be balanced with other sensory pathways such as quorum sensing, to identify the optimum current environment. The central sensory pathway in this process is common to most bacteria and most effectors. The environmental change is sensed by a sensory protein. In most species examined this is a transmembrane protein, sensing the external environment, but there is increasing evidence for additional cytoplasmic receptors in many species. All receptors, whether sensing sugars, amino acids or oxygen, share a cytoplasmic signalling domain that controls the activity of a

  16. Predictive Value of Decoy Receptor 3 in Postoperative Nosocomial Bacterial Meningitis

    Directory of Open Access Journals (Sweden)

    Yong-Juan Liu

    2014-11-01

    Full Text Available Nosocomial bacterial meningitis requires timely treatment, but what is difficult is the prompt and accurate diagnosis of this disease. The aim of this study was to assess the potential role of decoy receptor 3 (DcR3 levels in the differentiation of bacterial meningitis from non-bacterial meningitis. A total of 123 patients were recruited in this study, among them 80 patients being with bacterial meningitis and 43 patients with non-bacterial meningitis. Bacterial meningitis was confirmed by bacterial culture of cerebrospinal fluid (CSF culture and enzyme-linked immunosorbent assay (ELISA was used to detect the level of DcR3 in CSF. CSF levels of DcR3 were statistically significant between patients with bacterial meningitis and those with non-bacterial meningitis (p < 0.001. A total of 48.75% of patients with bacterial meningitis received antibiotic >24 h before CSF sampling, which was much higher than that of non-bacterial meningitis. CSF leucocyte count yielded the highest diagnostic value, with an area under the receiver operating characteristic curve (ROC of 0.928, followed by DcR3. At a critical value of 0.201 ng/mL for DcR3, the sensitivity and specificity were 78.75% and 81.40% respectively. DcR3 in CSF may be a valuable predictor for differentiating patients with bacterial meningitis from those with non-bacterial meningitis. Further studies are needed for the validation of this study.

  17. Chronic Ocular Hypertension after Treated Multifocal Bacterial Keratitis

    Directory of Open Access Journals (Sweden)

    Theodoros Athanassios Papadopoulos

    2013-02-01

    Full Text Available Purpose: To report an unusual case of multifocal bacterial keratitis that despite success-ful treatment caused chronic ocular hypertension. Methods: A 67-year-old woman with unilateral multifocal keratitis and no previous ocular pathology was admitted to our hospital. Corneal scrapings and conjunctival samples were obtained for culture and the patient received intensive therapy with fortified vancomycin and tobramycin eye drops. Results: The cultures demonstrated two strains of Staphylococcus epidermidis, one resistant to ciprofloxacin and both sensitive to vancomycin. Treatment was effective and gradually discontinued after total cessation of the inflammatory activity. During the follow-up period, the patient developed late and persistent ocular hypertension of unknown etiology, in absence of any detectable inflammation or complication, and received permanent antiglaucoma therapy. Conclusion: Differential diagnosis between fungal and bacterial infection is critical in cases of multifocal keratitis. Patients with multifocal bacterial keratitis may need intraocular pressure monitoring, even after complete infection healing.

  18. New Treatments for Bacterial Keratitis

    Directory of Open Access Journals (Sweden)

    Raymond L. M. Wong

    2012-01-01

    Full Text Available Purpose. To review the newer treatments for bacterial keratitis. Data Sources. PubMed literature search up to April 2012. Study Selection. Key words used for literature search: “infectious keratitis”, “microbial keratitis”, “infective keratitis”, “new treatments for infectious keratitis”, “fourth generation fluoroquinolones”, “moxifloxacin”, “gatifloxacin”, “collagen cross-linking”, and “photodynamic therapy”. Data Extraction. Over 2400 articles were retrieved. Large scale studies or publications at more recent dates were selected. Data Synthesis. Broad spectrum antibiotics have been the main stay of treatment for bacterial keratitis but with the emergence of bacterial resistance; there is a need for newer antimicrobial agents and treatment methods. Fourth-generation fluoroquinolones and corneal collagen cross-linking are amongst the new treatments. In vitro studies and prospective clinical trials have shown that fourth-generation fluoroquinolones are better than the older generation fluoroquinolones and are as potent as combined fortified antibiotics against common pathogens that cause bacterial keratitis. Collagen cross-linking was shown to improve healing of infectious corneal ulcer in treatment-resistant cases or as an adjunct to antibiotics treatment. Conclusion. Fourth-generation fluoroquinolones are good alternatives to standard treatment of bacterial keratitis using combined fortified topical antibiotics. Collagen cross-linking may be considered in treatment-resistant infectious keratitis or as an adjunct to antibiotics therapy.

  19. 培养与聚合酶链反应联合进行住院患儿肺炎细菌病原学检测%Bacterial etiology of pneumonia in hospitalized children:combined detection with culture and polymerase chain reaction

    Institute of Scientific and Technical Information of China (English)

    郑跃杰; 邓继岿; 赵瑞珍

    2008-01-01

    目的 探讨细菌培养与病原特异性DNA联合检测住院患儿肺炎细菌病原的应用价值.方法对187例肺炎患儿的深部呼吸道吸引物进行肺炎链球菌、流感嗜血杆菌选择性培养和普通培养,并且对同一标本采用靶序列富集多重PCR(Tem-PCB)扩增结合Luminex液态芯片检测平台进行定量测定,检测肺炎链球菌、流感嗜血杆菌、金黄色葡萄球菌、肺炎克雷伯杆菌、大肠杆菌、嗜肺军团菌、绿脓杆菌、鲍曼不动杆菌等14种病原菌的特异性DNA.结果细菌培养的总检出率为40.1%(75/187,含3例检出2种病原菌),病原菌依次为流感嗜血杆菌17.1%、大肠杆菌8.6%、肺炎克雷伯杆菌6.4%、金黄色葡萄球菌4.8%、肺炎链球菌3.7%、绿脓杆菌1.6%、鲍曼不动杆菌1.1%和阴沟肠杆菌1.1%.以细菌培养或Tem-PCR任一阳性为标准,联合检测的总检出率为78.6%(147/187),病原菌依次为流感嗜血杆菌28.9%、肺炎链球菌19.3%、大肠杆菌8.6%、肺炎克雷伯杆菌6.4%、金黄色葡萄球菌5.9%、鲍曼不动杆菌5.9%、绿脓杆菌2.7%和阴沟肠杆菌1.1%.结论 Tem-PCR能提高流感嗜血杆菌、肺炎链球菌、金黄色葡萄球菌、绿脓杆菌和鲍曼不动杆菌的检出例数.细菌培养与病原特异性DNA联合检测应用能显著提高肺炎病原的检出率,可能更真实地反映肺炎的细菌病原学情况.%Objective Bacterial cultures from respiratory aspirate or sputum have been the conventional diagnostic method for neumonia,but the results of culture was often affected by early extensive rise of antibiotics,sample collection and delivery.The objective of this stuay was to explore application of the combined detection of culture and polymerase chain reaction (PCR) assay in hospitalized children with pneumonia.Methods Totally 187 hospitalized children with pneumonia were enrolled.The age of the patients ranged from 1 month to 10 years,124 were male,63 female;175 of the patients receired

  20. Antibiotic resistance of bacterial biofilms

    DEFF Research Database (Denmark)

    Hoiby, N.; Bjarnsholt, T.; Givskov, M.;

    2010-01-01

    A biofilm is a structured consortium of bacteria embedded in a self-produced polymer matrix consisting of polysaccharide, protein and DNA. Bacterial biofilms cause chronic infections because they show increased tolerance to antibiotics and disinfectant chemicals as well as resisting phagocytosis...... and other components of the body's defence system. The persistence of, for example, staphylococcal infections related to foreign bodies is due to biofilm formation. Likewise, chronic Pseudomonas aeruginosa lung infection in cystic fibrosis patients is caused by biofilm-growing mucoid strains....... Characteristically, gradients of nutrients and oxygen exist from the top to the bottom of biofilms and these gradients are associated with decreased bacterial metabolic activity and increased doubling times of the bacterial cells; it is these more or less dormant cells that are responsible for some of the tolerance...

  1. Phylogenetic organization of bacterial activity.

    Science.gov (United States)

    Morrissey, Ember M; Mau, Rebecca L; Schwartz, Egbert; Caporaso, J Gregory; Dijkstra, Paul; van Gestel, Natasja; Koch, Benjamin J; Liu, Cindy M; Hayer, Michaela; McHugh, Theresa A; Marks, Jane C; Price, Lance B; Hungate, Bruce A

    2016-09-01

    Phylogeny is an ecologically meaningful way to classify plants and animals, as closely related taxa frequently have similar ecological characteristics, functional traits and effects on ecosystem processes. For bacteria, however, phylogeny has been argued to be an unreliable indicator of an organism's ecology owing to evolutionary processes more common to microbes such as gene loss and lateral gene transfer, as well as convergent evolution. Here we use advanced stable isotope probing with (13)C and (18)O to show that evolutionary history has ecological significance for in situ bacterial activity. Phylogenetic organization in the activity of bacteria sets the stage for characterizing the functional attributes of bacterial taxonomic groups. Connecting identity with function in this way will allow scientists to begin building a mechanistic understanding of how bacterial community composition regulates critical ecosystem functions. PMID:26943624

  2. Bacterial Degradation of Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Qing X. Li

    2009-01-01

    Full Text Available Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.

  3. Clinical applications of bacterial glycoproteins.

    Science.gov (United States)

    Fulton, Kelly M; Smith, Jeffrey C; Twine, Susan M

    2016-01-01

    There is an ongoing race between bacterial evolution and medical advances. Pathogens have the advantages of short generation times and horizontal gene transfer that enable rapid adaptation to new host environments and therapeutics that currently outpaces clinical research. Antibiotic resistance, the growing impact of nosocomial infections, cancer-causing bacteria, the risk of zoonosis, and the possibility of biowarfare all emphasize the increasingly urgent need for medical research focussed on bacterial pathogens. Bacterial glycoproteins are promising targets for alternative therapeutic intervention since they are often surface exposed, involved in host-pathogen interactions, required for virulence, and contain distinctive glycan structures. The potential exists to exploit these unique structures to improve clinical prevention, diagnosis, and treatment strategies. Translation of the potential in this field to actual clinical impact is an exciting prospect for fighting infectious diseases. PMID:26971465

  4. 硅壳包被的核壳型量子点荧光纳米颗粒的制备及其细菌计数的应用%Synthesis of Core/Shell Quantum Dots Doped Silica Nanoparticles and Their Application for Detecting Bacterial Count

    Institute of Scientific and Technical Information of China (English)

    傅昕; 张何; 黄可龙

    2012-01-01

    以氧化镉和硬脂酸锌为前驱体,合成了CdSe/ZnS核壳型量子点(QDs).采用反相微乳液技术,在温和条件下实现了硅壳包被的CdSe/ZnS荧光纳米颗粒的成功制备.在戊二醛的交联作用下,以金黄色葡萄球菌(S.aureus)为目标细菌、荧光纳米颗粒为荧光探针,建立了一种高灵敏的、简单快速的细菌计数的方法,并借助荧光显微镜成功地进行成像探测研究.通过考察荧光纳米颗粒与细菌的孵育时间、包入硅壳的核壳量子点质量等多种因素的影响.在最优化条件下,本方法的线性范围为5×102~5×107 CFU/mL;检出限为500 CFU/mL;线性回归方程为Y=494.96749X- 1194.25738(R=0.9960).本方法操作简单,检测时间短,有效克服了传统平板计数方法和基于有机染料的荧光检测方法存在的缺陷,提高了灵敏度.将此法用于6种实际样品的细菌数量测定,检测结果与平板计数方法基本一致,相对标准偏差在3.1%~8.2%之间,结果令人满意.%CdSe/ZnS core/shell quantum dots (QDs) were synthesized with cadmium oxide and zinc stearate as precursors. A reverse-microemulsion technique was used to synthesize CdSe/ZnS quantum dots doped silica nanoparticles modified with amine and phosphonate groups under very mild conditions. A highly sensitive, simple and rapid counting approach for bacteria was established by using fluorescent nanoparticles as a fluorescence label, Staphylococcus aureus (S. aureus) acted as detection target bacteria and glutaraldehyde as the crosslinker. The bacterial cell images were obtained using fluorescence microscopy. The effect of parameters such as reaction time and the amount of CdSe/ZnS in SiO2-coated fluorescent nanoparticles was discussed. Under the optimized conditions, a linear relationship of the fluorescence peak intensity (Y) and the total bacterial count (X) was established in the range of 5×102-107 CFU/mL using the equation F=494. 96749×-1194. 25738(R = 0. 9960). This

  5. 联合检测血清降钙素原、高敏C反应蛋白和全血白细胞在鉴别小儿细菌性和病毒性脑膜炎病中的重大意义%The Great Significance of Combined Detection of Serum Procalcitonin(PCT), High-sensitivity c-reactive Protein(hs - CRP) and White Blood Cells in Whole Blood in the Identification of Children with Bacterial Meningitis and Viral Meningitis

    Institute of Scientific and Technical Information of China (English)

    张保珍

    2016-01-01

    Objective To evaluate the significance of serum procalcitonin(PCT), high-sensitivity c-reactive protein(hs-CRP) and white blood cells in whole blood in identifying children with bacterial meningitis and viral meningitis.Methods To detecte PCT, hs-CRP and whole blood WBC taken from 42 children with bacterial meningitis, 56 children with viral meningitis and 40 healthy controls children.Results ①The level of PCT, hs-CRP and whole blood WBC in children with bacterial meningitis were significantly higher than that in control group. There was significant difference between the two groups(P0.05).②The combined detection of the three indicators in the identification of bacterial meningitis and viral encephalicis in accuracy, sensitivity and specificity was significantly higher than on an individual detection. There was significant difference between the two ways(P0.05).②三项指标联合检测鉴别细菌性和病毒性脑膜炎病在准确度,灵敏度和特异性上明显高于单独检测任一项指标,差异有统计学意义(P<0.05).结论 联合检测血清降钙素原、高敏C反应蛋白和全血白细胞有助于鉴别小儿细菌性和病毒性脑膜炎.

  6. The dynamics in the bacterial chemosensory arrays

    Science.gov (United States)

    Vaknin, Ady

    2014-08-01

    Bacterial chemoreceptors form two-dimensional sensory arrays on the cell membrane. These sensory arrays, which contain thousands of molecules, detect chemical changes in the environment of the bacterial cell and accordingly control its swimming behaviour, allowing these bacteria to track chemical gradients. It was recently demonstrated that stimulus, by ligand binding, alters the physical organization of these arrays, with dynamics that follow an apparent logarithmic time dependence. Such non-exponential dynamics is often observed in glass-like systems in which the internal dynamics slow down exponentially as the system approaches its equilibrium state. In a few of these `glassy' systems it was also demonstrated that after altering the equilibrium state of the system for a certain time tw the ensuing relaxation scales with tw. Here, we examined the relaxation of the receptor arrays in the bacterium E. coli after a perturbation by ligand binding for varying periods of times. We find that changing the time tw, during which the stimulus was present, affects mostly the deviation of the receptor arrays from equilibrium, but the dynamics of the relaxation seem to be independent of tw. A possible interpretation is discussed.

  7. Bacterial respiration of arsenic and selenium

    Science.gov (United States)

    Stolz, J.F.; Oremland, R.S.

    1999-01-01

    Oxyanions of arsenic and selenium can be used in microbial anaerobic respiration as terminal electron acceptors. The detection of arsenate and selenate respiring bacteria in numerous pristine and contaminated environments and their rapid appearance in enrichment culture suggest that they are widespread and metabolically active in nature. Although the bacterial species that have been isolated and characterized are still few in number, they are scattered throughout the bacterial domain and include Gram- positive bacteria, beta, gamma and epsilon Proteobacteria and the sole member of a deeply branching lineage of the bacteria, Chrysiogenes arsenatus. The oxidation of a number of organic substrates (i.e. acetate, lactate, pyruvate, glycerol, ethanol) or hydrogen can be coupled to the reduction of arsenate and selenate, but the actual donor used varies from species to species. Both periplasmic and membrane-associated arsenate and selenate reductases have been characterized. Although the number of subunits and molecular masses differs, they all contain molybdenum. The extent of the environmental impact on the transformation and mobilization of arsenic and selenium by microbial dissimilatory processes is only now being fully appreciated.

  8. Genetic Identification and Risk Factor Analysis of Asymptomatic Bacterial Colonization on Cardiovascular Implantable Electronic Devices

    Science.gov (United States)

    Chu, Xian-Ming; An, Yi; Li, Xue-Bin; Guo, Ji-Hong

    2014-01-01

    Asymptomatic bacterial colonization of cardiovascular implantable electronic devices (CIEDs) is widespread and increases the risk of clinical CIED infection. The aim of the study was to evaluate the incidence of bacterial colonization of generator pockets in patients without signs of infection and to analyze the relationship with clinical infection and risk factors. From June 2011 to December 2012, 78 patients underwent CIED replacement or upgrade. Exclusion criteria included a clinical diagnosis of CIED infection, bacteremia, or infective endocarditis. All patients were examined for evidence of bacterial 16S rDNA on the device and in the surrounding tissues. Infection cases were recorded during follow-up. The bacterial-positive rate was 38.5% (30 cases); the coagulase-negative Staphylococcus detection rate was the highest (9 cases, 11.5%). Positive bacterial DNA results were obtained from pocket tissue in 23.1% of patients (18 cases), and bacterial DNA was detected on the device in 29.5% of patients (23 cases). During follow-up (median 24.6 months), two patients (6.7%, 2/30) became symptomatic with the same species of microorganism, S. aureus and S. epidermidis. Multivariable logistic regression analysis found that the history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency, and renal insufficiency were independent risk factors for asymptomatic bacterial colonization. PMID:25530969

  9. Genetic Identification and Risk Factor Analysis of Asymptomatic Bacterial Colonization on Cardiovascular Implantable Electronic Devices

    Directory of Open Access Journals (Sweden)

    Xian-Ming Chu

    2014-01-01

    Full Text Available Asymptomatic bacterial colonization of cardiovascular implantable electronic devices (CIEDs is widespread and increases the risk of clinical CIED infection. The aim of the study was to evaluate the incidence of bacterial colonization of generator pockets in patients without signs of infection and to analyze the relationship with clinical infection and risk factors. From June 2011 to December 2012, 78 patients underwent CIED replacement or upgrade. Exclusion criteria included a clinical diagnosis of CIED infection, bacteremia, or infective endocarditis. All patients were examined for evidence of bacterial 16S rDNA on the device and in the surrounding tissues. Infection cases were recorded during follow-up. The bacterial-positive rate was 38.5% (30 cases; the coagulase-negative Staphylococcus detection rate was the highest (9 cases, 11.5%. Positive bacterial DNA results were obtained from pocket tissue in 23.1% of patients (18 cases, and bacterial DNA was detected on the device in 29.5% of patients (23 cases. During follow-up (median 24.6 months, two patients (6.7%, 2/30 became symptomatic with the same species of microorganism, S. aureus and S. epidermidis. Multivariable logistic regression analysis found that the history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency, and renal insufficiency were independent risk factors for asymptomatic bacterial colonization.

  10. Moonmilk deposits originate from specific bacterial communities in Altamira Cave (Spain).

    Science.gov (United States)

    Portillo, Maria C; Gonzalez, Juan M

    2011-01-01

    The influence of bacterial communities on the formation of carbonate deposits such as moonmilk was investigated in Altamira Cave (Spain). The study focuses on the relationship between the bacterial communities at moonmilk deposits and those forming white colonizations, which develop sporadically throughout the cave. Using molecular fingerprinting of the metabolically active bacterial communities detected through RNA analyses, the development of white colonizations and moonmilk deposits showed similar bacterial profiles. White colonizations were able to raise the pH as a result of their metabolism (reaching in situ pH values above 8.5), which was proportional to the nutrient supply. Bacterial activity was analyzed by nanorespirometry showing higher metabolic activity from bacterial colonizations than uncolonized areas. Once carbonate deposits were formed, bacterial activity decreased drastically (down to 5.7% of the white colonization activity). This study reports on a specific type of bacterial community leading to moonmilk deposit formation in a cave environment as a result of bacterial metabolism. The consequence of this process is a macroscopic phenomenon of visible carbonate depositions and accumulation in cave environments. PMID:20717660

  11. The physical basis of bacterial quorum communication

    CERN Document Server

    2015-01-01

    This book aims to educate physical scientists and quantitatively-oriented biologists on the application of physical experimentation and analysis, together with appropriate modeling, to understanding and interpreting microbial chemical communication and especially quorum sensing (QS). Quorum sensing describes a chemical communication behavior that is nearly universal among bacteria. Individual cells release a diffusible small molecule (an autoinducer) into their environment. A high concentration of this autoinducer serves as a signal of high population density, triggering new patterns of gene expression throughout the population. However QS is often much more complex than simple census-taking. Many QS bacteria produce and detect multiple autoinducers, which generate quorum signal cross talk with each other and with other bacterial species. QS gene regulatory networks operate in physically complex environments and respond to a range of inputs in addition to autoinducer signals. While many individual QS systems ...

  12. Endophytic bacterial and fungal microbiota in sprouts, roots and stems of rice (Oryza sativa L.).

    Science.gov (United States)

    Wang, Wenfeng; Zhai, Yanyan; Cao, Lixiang; Tan, Hongming; Zhang, Renduo

    2016-01-01

    The objective of this study was to elucidate the endophytic microbiota in rice sprouts, roots, and stems, and their transmission in the plant development. Prior to DNA extraction, roots and stems were treated with 36% formaldehyde and 0.1M NaOH solutions to remove epiphytic bacterial whole 16S rRNA genes. Bacterial and fungal taxa in the sprout, root, and stem samples were analyzed using Illumina-based sequencing of the V3-V4 hyper variable regions of bacterial 16S rRNA genes and the ITS2 regions of fungal rRNA genes, respectively. Results showed that more diverse bacterial OTUs were detected in roots than in stems, while more diverse fungal OTUs were detected in stems than in roots. Compared with the endophytic microbiota in sprouts, the bacterial OTUs increased in roots but decreased in stems, whereas the fungal OTUs in both stems and roots decreased. Sprout-borne bacterial genera Sphingomonas and Pseudomonus, and fungal genera Fusarium, Pestalotiopsis, and Penicillium were detected in stems and roots. The coexistence of these indigenous bacterial and fungal taxa in sprouts, roots, and stems indicated their transmission during the development from sprouts to mature plants. The results from this study should be useful to better understand the plant-microbe interactions and to select suitable microbial taxa for rice production. PMID:27296957

  13. Disease notes - Bacterial root rot

    Science.gov (United States)

    Bacterial root rot initiated by lactic acid bacteria, particularly Leuconostoc, occurs every year in Idaho sugarbeet fields. Hot fall weather seems to make the problem worse. Although Leuconostoc initiates the rot, other bacteria and yeast frequently invade the tissue as well. The acetic acid bac...

  14. Biotechnological applications of bacterial cellulases

    Directory of Open Access Journals (Sweden)

    Esther Menendez

    2015-08-01

    Full Text Available Cellulases have numerous applications in several industries, including biofuel production, food and feed industry, brewing, pulp and paper, textile, laundry, and agriculture.Cellulose-degrading bacteria are widely spread in nature, being isolated from quite different environments. Cellulose degradation is the result of a synergic process between an endoglucanase, an exoglucanase and a,β-glucosidase. Bacterial endoglucanases degrade ß-1,4-glucan linkages of cellulose amorphous zones, meanwhile exoglucanases cleave the remaining oligosaccharide chains, originating cellobiose, which is hydrolyzed by ß-glucanases. Bacterial cellulases (EC 3.2.1.4 are comprised in fourteen Glycosil Hydrolase families. Several advantages, such as higher growth rates and genetic versatility, emphasize the suitability and advantages of bacterial cellulases over other sources for this group of enzymes. This review summarizes the main known cellulolytic bacteria and the best strategies to optimize their cellulase production, focusing on endoglucanases, as well as it reviews the main biotechnological applications of bacterial cellulases in several industries, medicine and agriculture.

  15. Molecular Mechanisms Underlying Bacterial Persisters

    DEFF Research Database (Denmark)

    Maisonneuve, Etienne; Gerdes, Kenn

    2014-01-01

    technological advances in microfluidics and reporter genes have improved this scenario. Here, we summarize recent progress in the field, revealing the ubiquitous bacterial stress alarmone ppGpp as an emerging central regulator of multidrug tolerance and persistence, both in stochastically and environmentally...

  16. Bacterial genome reengineering.

    Science.gov (United States)

    Zhou, Jindan; Rudd, Kenneth E

    2011-01-01

    The web application PrimerPair at ecogene.org generates large sets of paired DNA sequences surrounding- all protein and RNA genes of Escherichia coli K-12. Many DNA fragments, which these primers amplify, can be used to implement a genome reengineering strategy using complementary in vitro cloning and in vivo recombineering. The integration of a primer design tool with a model organism database increases the level of quality control. Computer-assisted design of gene primer pairs relies upon having highly accurate genomic DNA sequence information that exactly matches the DNA of the cells being used in the laboratory to ensure predictable DNA hybridizations. It is equally crucial to have confidence that the predicted start codons define the locations of genes accurately. Annotations in the EcoGene database are queried by PrimerPair to eliminate pseudogenes, IS elements, and other problematic genes before the design process starts. These projects progressively familiarize users with the EcoGene content, scope, and application interfaces that are useful for genome reengineering projects. The first protocol leads to the design of a pair of primer sequences that were used to clone and express a single gene. The N-terminal protein sequence was experimentally verified and the protein was detected in the periplasm. This is followed by instructions to design PCR primer pairs for cloning gene fragments encoding 50 periplasmic proteins without their signal peptides. The design process begins with the user simply designating one pair of forward and reverse primer endpoint positions relative to all start and stop codon positions. The gene name, genomic coordinates, and primer DNA sequences are reported to the user. When making chromosomal deletions, the integrity of the provisional primer design is checked to see whether it will generate any unwanted double deletions with adjacent genes. The bad designs are recalculated and replacement primers are provided alongside the

  17. Cognitive outcome in adults after bacterial meningitis.

    NARCIS (Netherlands)

    Hoogman, M.; Beek, D. van de; Weisfelt, M.; Gans, J. de; Schmand, B.

    2007-01-01

    OBJECTIVE: To evaluate cognitive outcome in adult survivors of bacterial meningitis. METHODS: Data from three prospective multicentre studies were pooled and reanalysed, involving 155 adults surviving bacterial meningitis (79 after pneumococcal and 76 after meningococcal meningitis) and 72 healthy c

  18. Total viable bacterial count using a real time all-fibre spectroscopic system.

    Science.gov (United States)

    Bogomolny, E; Swift, S; Vanholsbeeck, F

    2013-07-21

    Rapid, accurate and sensitive enumeration of bacterial populations in the natural environment is an essential task for many research fields. Widely used standard methods for counting bacteria such as heterotrophic plate count require 1 to 8 days of incubation time for limited accuracy, while more accurate and rapid techniques are often expensive and may require bulky equipment. In the present study, we have developed a computerized optical prototype for bacterial detection. The goal of this research was to estimate the potential of this optical system for Total Viable Bacterial Count in water. For this purpose, we tested water batches with different microbiological content. Bacterial detection was based on fluorescence enhanced by nucleic acid staining. High sensitivity was achieved by a stable diode pumped solid state laser, sensitive CCD spectrometer and in situ excitation and signal collection. The results have shown that the bacterial count from different water origins using our optical setup along with multivariate analysis presents a higher accuracy and a shorter detection time compared to standard methods. For example, in a case where the fluorescence signal is calibrated to the water batch regression line, the relative standard deviation of the optical system enumeration varies between 21 and 36%, while that of the heterotropic plate count counterpart varies between 41 and 59%. In summary, we conclude that the all-fibre optical system may offer the following advantages over conventional methods: near real time examinations, portability, sensitivity, accuracy and ability to detect 10(2) to 10(8) CFU per ml bacterial concentrations.

  19. Juvenile idiopathic arthritis and rheumatoid arthritis: bacterial diversity in temporomandibular joint synovial fluid in comparison with immunological and clinical findings.

    Science.gov (United States)

    Olsen-Bergem, H; Kristoffersen, A K; Bjørnland, T; Reseland, J E; Aas, J A

    2016-03-01

    Temporomandibular joint (TMJ) involvement in juvenile idiopathic arthritis (JIA) occurs in up to 80% of affected children. The purpose of this study was to investigate the presence of bacterial DNA in synovial fluid, and to compare this with clinical and immunological findings in children with JIA, adults with persistent JIA, and adults with rheumatoid arthritis, in order to detect whether bacteria contribute to inflammation in TMJ arthritis. Synovial fluid and skin swab samples were collected from 30 patients (54 TMJs). Bacterial detection was performed using 16S rRNA pyrosequencing. Bacterial DNA was detected in 31 TMJs (57%) in 19 patients (63%). A positive statistically significant correlation was registered between bacterial DNA detected in TMJ synovial fluid and the following factors: total protein concentration in synovial fluid, interleukin 1β, tumour necrosis factor alpha, adrenocorticotropic hormone, and adiponectin, as well as the duration of the general medical disease. Fourteen different bacterial species were detected in synovial fluid. Bacterial DNA in TMJ synovial fluid without contamination was detected in more than 50% of the patients. Studies are needed to evaluate the consequences of this bacterial DNA in synovial fluid with regard to TMJ arthritis. PMID:26554824

  20. Diagnostic Accuracy of Procalcitonin in Bacterial Meningitis Versus Nonbacterial Meningitis

    OpenAIRE

    Wei, Ting-Ting; Hu, Zhi-De; Qin, Bao-Dong; Ma, Ning; Tang, Qing-Qin; Wang, Li-li; ZHOU, Lin; Zhong, Ren-Qian

    2016-01-01

    Abstract Several studies have investigated the diagnostic accuracy of procalcitonin (PCT) levels in blood or cerebrospinal fluid (CSF) in bacterial meningitis (BM), but the results were heterogeneous. The aim of the present study was to ascertain the diagnostic accuracy of PCT as a marker for BM detection. A systematic search of the EMBASE, Scopus, Web of Science, and PubMed databases was performed to identify studies published before December 7, 2015 investigating the diagnostic accuracy of ...

  1. Bacterial community survey of sediments at Naracoorte Caves, Australia

    OpenAIRE

    Ball Andrew S.; Kirby Greg; Bourne Steven; Cao Xiangsheng; Mazaheri Nezhad Fard Ramin; Adetutu Eric M.; Shahsavari Esamaeil; Thorpe Krystal

    2012-01-01

    Bacterial diversity in sediments at UNESCO World Heritage listed Naracoorte Caves was surveyed as part of an investigation carried out in a larger study on assessing microbial communities in caves. Cave selection was based on tourist accessibility; Stick Tomato and Alexandra Cave (> 15000 annual visits) and Strawhaven Cave was used as control (no tourist access). Microbial analysis showed that Bacillus was the most commonly detected microbial genus by culture dependent and independent survey ...

  2. Development of a chemically defined medium for studying foodborne bacterial-fungal interactions

    DEFF Research Database (Denmark)

    Aunsbjerg, Stina Dissing; Honoré, Anders Hans; Vogensen, Finn Kvist;

    2015-01-01

    There is a growing interest for using natural preservatives in the food and dairy industries including the application of bacterial cultures to inhibit fungal spoilage. Several antifungal metabolites from bacteria have been identified, but their relative importance has been difficult to establish...... fermented milk products. Both strong and weak antifungal interactions observed in milk could be reproduced in CDIM. The medium seems suitable for studying antifungal activity of bacterial cultures.......There is a growing interest for using natural preservatives in the food and dairy industries including the application of bacterial cultures to inhibit fungal spoilage. Several antifungal metabolites from bacteria have been identified, but their relative importance has been difficult to establish....... In dynamic systems such as fermented milk products, the complexity of the food matrix affects detection, identification and quantification of antifungal metabolites, and thereby the understanding of the bacterial-fungal interactions. To ease the identification and quantification of bacterial metabolites (as...

  3. Filtration properties of bacterial cellulose membranes

    OpenAIRE

    Lehtonen, Janika

    2015-01-01

    Bacterial cellulose has the same molecular formula as cellulose from plant origin, but it is characterized by several unique properties including high purity, crystallinity and mechanical strength. These properties are dependent on parameters such as the bacterial strain used, the cultivation conditions and post-growth processing. The possibility to achieve bacterial cellulose membranes with different properties by varying these parameters could make bacterial cellulose an interesting materi...

  4. The burden of bacterial vaginosis: women's experience of the physical, emotional, sexual and social impact of living with recurrent bacterial vaginosis.

    Directory of Open Access Journals (Sweden)

    Jade E Bilardi

    Full Text Available BACKGROUND: Bacterial vaginosis is a common vaginal infection, causing an abnormal vaginal discharge and/or odour in up to 50% of sufferers. Recurrence is common following recommended treatment. There are limited data on women's experience of bacterial vaginosis, and the impact on their self-esteem, sexual relationships and quality of life. The aim of this study was to explore the experiences and impact of recurrent bacterial vaginosis on women. METHODS: A social constructionist approach was chosen as the framework for the study. Thirty five women with male and/or female partners participated in semi-structured interviews face-to-face or by telephone about their experience of recurrent bacterial vaginosis. RESULTS: Recurrent bacterial vaginosis impacted on women to varying degrees, with some women reporting it had little impact on their lives but most reporting it had a moderate to severe impact. The degree to which it impacted on women physically, emotionally, sexually and socially often depended on the frequency of episodes and severity of symptoms. Women commonly reported that symptoms of bacterial vaginosis made them feel embarrassed, ashamed, 'dirty' and very concerned others may detect their malodour and abnormal discharge. The biggest impact of recurrent bacterial vaginosis was on women's self-esteem and sex lives, with women regularly avoiding sexual activity, in particular oral sex, as they were too embarrassed and self-conscious of their symptoms to engage in these activities. Women often felt confused about why they were experiencing recurrent bacterial vaginosis and frustrated at their lack of control over recurrence. CONCLUSION: Women's experience of recurrent bacterial vaginosis varied broadly and significantly in this study. Some women reported little impact on their lives but most reported a moderate to severe impact, mainly on their self-esteem and sex life. Further support and acknowledgement of these impacts are required when

  5. Bacterial community diversity in municipal waste landfill sites.

    Science.gov (United States)

    Song, Liyan; Wang, Yangqing; Tang, Wei; Lei, Yu

    2015-09-01

    Little is known about the bacterial diversity of landfills and how environmental factors impact the diversity. In this study, PCR-based 454 pyrosequencing was used to investigate the bacterial communities of ten landfill leachate samples from five landfill sites in China. A total of 137 K useable sequences from the V3-V6 regions of the 16S rRNA gene were retrieved from 205 K reads. These sequences revealed the presence of a large number of operational taxonomic units (OTUs) in the landfills (709-1599 OTUs per sample). The most predominant bacterial representatives in the landfills investigated, regardless of geographic area, included Gammaproteobacteria, Firmicutes, and Bacteroidetes. The phyla Fusobacteria and Tenericutes were also found for the first time to be predominant in the landfills. The phylum Fusobacteria predominated (51.5 and 48.8%) in two semi-arid landfills, and the phylum Tenericutes dominated (30.6%) at one humid, subtropical landfill. Further, a large number of Pseudomonas was detected in most samples, comprising the dominant group and accounting for 40.9 to 92.4% of the total abundance. Principal component analysis (PCA) and cluster analysis based on OTU abundance showed that the abundant taxa separated the bacterial community. Canonical correlation analysis (CCA) suggested that precipitation and landfilling age significantly impact on the bacterial community structure. The bacterial community function (e.g., cellulolytic bacteria, sulfate-reducing bacteria (SRB), sulfate-oxidizing bacteria, and xenobiotic organic compound (XOC)-degrading bacteria) was also diverse, but the pattern is unclear.

  6. 环介导等温扩增技术在检测细菌性肺炎常见致病菌中的应用%Value of loop-mediated isothermal amplification in detection of common pathogens of bacterial pneumonia

    Institute of Scientific and Technical Information of China (English)

    戴然然; 刘嘉琳; 万欢英

    2011-01-01

    Objective To investigate the value of loop-mediated isothermal amplification (LAMP) assay in the etiology diagnosis of bacterial pnuemonia through nucleic acid detection of common pathogens in pneumonia patients by LAMP method. Methods Sputum DNA was extracted from 75 pneumonia patients. DNA was amplified by LAMP. The fluorescence signals of products were detected by real-time PCR. The quantitative results were qualitatively analyzed at different cutoff values, and the data were compared with the results of sputum culture. Results The positive ratio of amplified products with LAMP assay at the cutoff value of 1 × 104 was 68.0% ,and the coincidence rate between LAMP assay and sputum culture was 56.0%. The positive ratio of amplified products with LAMP assay at the cutoff value of 1× 105 was 50.7%, and the coincidence rate between LAMP assay and sputum culture was 58.7%.The positive ratio of amplified products with LAMP assay at the cutoff value of 1 × 106 was 30.7%, and the coincidence rate between LAMP assay and sputum culture was 53.3%. There was no statistical significance on the positive rate between sputum culture and LAMP results at the cutoff value of 1 × 105.The detection rate of parts of bacteria by LAMP assay is higher than that by sputum culture at the cutoff value of 1 × 105 ,especially for the harsh bacteria. Conclusions DNA of common pathogens in sputum of patients with bacterial pneumonia can be easily and quickly amplified by LAMP method to identify pathogenic bacteria types. Compared with sputum culture, the bacterial detection rate is higher by LAMP assay at the cutoff value of 1 × 105. Especially for the harsh bacteria, LAMP method has significant advantages.%目的 应用环介导等温扩增(LAMP)方法对肺炎患者痰液常见致病菌进行核酸检测,研究LAMP方法在细菌性肺炎病原学诊断中的价值.方法 抽提75例肺炎患者痰液细菌DNA,根据肺炎常见8种致病细菌设计引物,应用LAMP技术扩增DNA,实

  7. Distribution of Triplet Separators in Bacterial Genomes

    Institute of Scientific and Technical Information of China (English)

    HU Rui; ZHENG Wei-Mou

    2001-01-01

    Distributions of triplet separator lengths for two bacterial complete genomes are analyzed. The theoretical distributions for the independent random sequence and the first-order Markov chain are derived and compared with the distributions of the bacterial genomes. A prominent double band structure, which does not exist in the theoretical distributions, is observed in the bacterial distributions for most triplets.``

  8. Bacteriophage-encoded shiga toxin gene in atypical bacterial host

    Directory of Open Access Journals (Sweden)

    Casas Veronica

    2011-07-01

    Full Text Available Abstract Background Contamination from fecal bacteria in recreational waters is a major health concern since bacteria capable of causing human disease can be found in animal feces. The Dog Beach area of Ocean Beach in San Diego, California is a beach prone to closures due to high levels of fecal indicator bacteria (FIB. A potential source of these FIB could be the canine feces left behind by owners who do not clean up after their pets. We tested this hypothesis by screening the DNA isolated from canine feces for the bacteriophage-encoded stx gene normally found in the virulent strains of the fecal bacterium Escherichia coli. Results Twenty canine fecal samples were collected, processed for total and bacterial fraction DNA, and screened by PCR for the stx gene. The stx gene was detected in the total and bacterial fraction DNA of one fecal sample. Bacterial isolates were then cultivated from the stx-positive fecal sample. Eighty nine of these canine fecal bacterial isolates were screened by PCR for the stx gene. The stx gene was detected in five of these isolates. Sequencing and phylogenetic analyses of 16S rRNA gene PCR products from the canine fecal bacterial isolates indicated that they were Enterococcus and not E. coli. Conclusions The bacteriophage-encoded stx gene was found in multiple species of bacteria cultivated from canine fecal samples gathered at the shoreline of the Dog Beach area of Ocean Beach in San Diego, California. The canine fecal bacteria carrying the stx gene were not the typical E. coli host and were instead identified through phylogenetic analyses as Enterococcus. This suggests a large degree of horizontal gene transfer of exotoxin genes in recreational waters.

  9. Bacteriophage-Based Pathogen Detection

    Science.gov (United States)

    Ripp, Steven

    Considered the most abundant organism on Earth, at a population approaching 1031, bacteriophage, or phage for short, mediate interactions with myriad bacterial hosts that has for decades been exploited in phage typing schemes for signature identification of clinical, food-borne, and water-borne pathogens. With over 5,000 phage being morphologically characterized and grouped as to susceptible host, there exists an enormous cache of bacterial-specific sensors that has more recently been incorporated into novel bio-recognition assays with heightened sensitivity, specificity, and speed. These assays take many forms, ranging from straightforward visualization of labeled phage as they attach to their specific bacterial hosts to reporter phage that genetically deposit trackable signals within their bacterial hosts to the detection of progeny phage or other uniquely identifiable elements released from infected host cells. A comprehensive review of these and other phage-based detection assays, as directed towards the detection and monitoring of bacterial pathogens, will be provided in this chapter.

  10. Bacterial populations on brewery filling hall surfaces as revealed by next-generation sequencing.

    Science.gov (United States)

    Priha, Outi; Raulio, Mari; Maukonen, Johanna; Vehviläinen, Anna-Kaisa; Storgårds, Erna

    2016-01-01

    Due to the presence of moisture and nutrients, brewery filling line surfaces are susceptible to unwanted microbial attachment. Knowledge of the attaching microbes will aid in designing hygienic control of the process. In this study the bacterial diversity present on brewery filling line surfaces was revealed by next generation sequencing. The two filling lines studied maintained their characteristic bacterial community throughout three sampling times (13-163 days). On the glass bottle line, γ-proteobacteria dominated (35-82% of all OTUs), whereas on the canning line α-, β- and γ-proteobacteria and actinobacteria were most common. The most frequently detected genera were Acinetobacter, Propinobacterium and Pseudomonas. The halophilic genus Halomonas was commonly detected, which might be due to its tolerance to alkaline foam cleaners. This study has revealed a detailed overall picture of the bacterial groups present on filling line surfaces. Further effort should be given to determine the efficacy of washing procedures on different bacterial groups. PMID:27064426

  11. Bacterial chromosome organization and segregation.

    Science.gov (United States)

    Badrinarayanan, Anjana; Le, Tung B K; Laub, Michael T

    2015-01-01

    If fully stretched out, a typical bacterial chromosome would be nearly 1 mm long, approximately 1,000 times the length of a cell. Not only must cells massively compact their genetic material, but they must also organize their DNA in a manner that is compatible with a range of cellular processes, including DNA replication, DNA repair, homologous recombination, and horizontal gene transfer. Recent work, driven in part by technological advances, has begun to reveal the general principles of chromosome organization in bacteria. Here, drawing on studies of many different organisms, we review the emerging picture of how bacterial chromosomes are structured at multiple length scales, highlighting the functions of various DNA-binding proteins and the impact of physical forces. Additionally, we discuss the spatial dynamics of chromosomes, particularly during their segregation to daughter cells. Although there has been tremendous progress, we also highlight gaps that remain in understanding chromosome organization and segregation. PMID:26566111

  12. Bacterial streamers in curved microchannels

    Science.gov (United States)

    Rusconi, Roberto; Lecuyer, Sigolene; Guglielmini, Laura; Stone, Howard

    2009-11-01

    Biofilms, generally identified as microbial communities embedded in a self-produced matrix of extracellular polymeric substances, are involved in a wide variety of health-related problems ranging from implant-associated infections to disease transmissions and dental plaque. The usual picture of these bacterial films is that they grow and develop on surfaces. However, suspended biofilm structures, or streamers, have been found in natural environments (e.g., rivers, acid mines, hydrothermal hot springs) and are always suggested to stem from a turbulent flow. We report the formation of bacterial streamers in curved microfluidic channels. By using confocal laser microscopy we are able to directly image and characterize the spatial and temporal evolution of these filamentous structures. Such streamers, which always connect the inner corners of opposite sides of the channel, are always located in the middle plane. Numerical simulations of the flow provide evidences for an underlying hydrodynamic mechanism behind the formation of the streamers.

  13. Bacterial survival in Martian conditions

    CERN Document Server

    D'Alessandro, Giuseppe Galletta; Giulio Bertoloni; Maurizio

    2010-01-01

    We shortly discuss the observable consequences of the two hypotheses about the origin of life on Earth and Mars: the Lithopanspermia (Mars to Earth or viceversa) and the origin from a unique progenitor, that for Earth is called LUCA (the LUCA hypothesis). To test the possibility that some lifeforms similar to the terrestrial ones may survive on Mars, we designed and built two simulators of Martian environments where to perform experiments with different bacterial strains: LISA and mini-LISA. Our LISA environmental chambers can reproduce the conditions of many Martian locations near the surface trough changes of temperature, pressure, UV fluence and atmospheric composition. Both simulators are open to collaboration with other laboratories interested in performing experiments on many kind of samples (biological, minerals, electronic) in situations similar to that of the red planet. Inside LISA we have studied the survival of several bacterial strains and endospores. We verified that the UV light is the major re...

  14. Collective Functionality through Bacterial Individuality

    Science.gov (United States)

    Ackermann, Martin

    According to the conventional view, the properties of an organism are a product of nature and nurture - of its genes and the environment it lives in. Recent experiments with unicellular organisms have challenged this view: several molecular mechanisms generate phenotypic variation independently of environmental signals, leading to variation in clonal groups. My presentation will focus on the causes and consequences of this microbial individuality. Using examples from bacterial genetic model systems, I will first discuss different molecular and cellular mechanisms that give rise to bacterial individuality. Then, I will discuss the consequences of individuality, and focus on how phenotypic variation in clonal populations of bacteria can promote interactions between individuals, lead to the division of labor, and allow clonal groups of bacteria to cope with environmental uncertainty. Variation between individuals thus provides clonal groups with collective functionality.

  15. Shedding light on biology of bacterial cells.

    Science.gov (United States)

    Schneider, Johannes P; Basler, Marek

    2016-11-01

    To understand basic principles of living organisms one has to know many different properties of all cellular components, their mutual interactions but also their amounts and spatial organization. Live-cell imaging is one possible approach to obtain such data. To get multiple snapshots of a cellular process, the imaging approach has to be gentle enough to not disrupt basic functions of the cell but also have high temporal and spatial resolution to detect and describe the changes. Light microscopy has become a method of choice and since its early development over 300 years ago revolutionized our understanding of living organisms. As most cellular components are indistinguishable from the rest of the cellular contents, the second revolution came from a discovery of specific labelling techniques, such as fusions to fluorescent proteins that allowed specific tracking of a component of interest. Currently, several different tags can be tracked independently and this allows us to simultaneously monitor the dynamics of several cellular components and from the correlation of their dynamics to infer their respective functions. It is, therefore, not surprising that live-cell fluorescence microscopy significantly advanced our understanding of basic cellular processes. Current cameras are fast enough to detect changes with millisecond time resolution and are sensitive enough to detect even a few photons per pixel. Together with constant improvement of properties of fluorescent tags, it is now possible to track single molecules in living cells over an extended period of time with a great temporal resolution. The parallel development of new illumination and detection techniques allowed breaking the diffraction barrier and thus further pushed the resolution limit of light microscopy. In this review, we would like to cover recent advances in live-cell imaging technology relevant to bacterial cells and provide a few examples of research that has been possible due to imaging

  16. Bacterial communication and group behavior

    OpenAIRE

    Greenberg, E. Peter

    2003-01-01

    The existence of species-specific and interspecies bacterial cell-cell communication and group organization was only recently accepted. Researchers are now realizing that the ability of these microbial teams to communicate and form structures, known as biofilms, at key times during the establishment of infection significantly increases their ability to evade both host defenses and antibiotics. This Perspective series discusses the known signaling mechanisms, the roles they play in both chroni...

  17. Bacterial survival in Martian conditions

    OpenAIRE

    Galletta, Giuseppe; Bertoloni, Giulio; D'Alessandro, Maurizio

    2010-01-01

    We shortly discuss the observable consequences of the two hypotheses about the origin of life on Earth and Mars: the Lithopanspermia (Mars to Earth or viceversa) and the origin from a unique progenitor, that for Earth is called LUCA (the LUCA hypothesis). To test the possibility that some lifeforms similar to the terrestrial ones may survive on Mars, we designed and built two simulators of Martian environments where to perform experiments with different bacterial strains: LISA and mini-LISA. ...

  18. Small intestinal bacterial overgrowth syndrome

    Institute of Scientific and Technical Information of China (English)

    Jan; Bures; Jiri; Cyrany; Darina; Kohoutova; Miroslav; Frstl; Stanislav; Rejchrt; Jaroslav; Kvetina; Viktor; Vorisek; Marcela; Kopacova

    2010-01-01

    Human intestinal microbiota create a complex polymi-crobial ecology. This is characterised by its high population density, wide diversity and complexity of interaction. Any dysbalance of this complex intestinal microbiome, both qualitative and quantitative, might have serious health consequence for a macro-organism, including small intestinal bacterial overgrowth syndrome (SIBO).SIBO is defined as an increase in the number and/or alteration in the type of bacteria in the upper gastro-intestinal tract. There...

  19. Population dynamics of bacterial persistence

    OpenAIRE

    Patra, Pintu

    2014-01-01

    The life of microorganisms is characterized by two main tasks, rapid growth under conditions permitting growth and survival under stressful conditions. The environments, in which microorganisms dwell, vary in space and time. The microorganisms innovate diverse strategies to readily adapt to the regularly fluctuating environments. Phenotypic heterogeneity is one such strategy, where an isogenic population splits into subpopulations that respond differently under identical environments. Bacteri...

  20. Immunization by a bacterial aerosol

    OpenAIRE

    Garcia-Contreras, Lucila; Wong, Yun-Ling; Muttil, Pavan; Padilla, Danielle; Sadoff, Jerry; DeRousse, Jessica; Germishuizen, Willem Andreas; Goonesekera, Sunali; Elbert, Katharina; Bloom, Barry R.; Miller, Rich; Fourie, P. Bernard; Hickey, Anthony; Edwards, David

    2008-01-01

    By manufacturing a single-particle system in two particulate forms (i.e., micrometer size and nanometer size), we have designed a bacterial vaccine form that exhibits improved efficacy of immunization. Microstructural properties are adapted to alter dispersive and aerosol properties independently. Dried “nanomicroparticle” vaccines possess two axes of nanoscale dimensions and a third axis of micrometer dimension; the last one permits effective micrometer-like physical dispersion, and the form...

  1. Molecular approaches for bacterial azoreductases

    OpenAIRE

    Montira Leelakriangsak

    2013-01-01

    Azo dyes are the dominant types of synthetic dyes, widely used in textiles, foods, leather, printing, tattooing, cosmetics, and pharmaceutical industries. Many microorganisms are able to decolorize azo dyes, and there is increasing interest in biological waste treatment methods. Bacterial azoreductases can cleave azo linkages (-N=N-) in azo dyes, forming aromatic amines. This review mainly focuses on employing molecular approaches, including gene manipulation and recombinant strains, to study...

  2. Bacterial meningitis by streptococcus agalactiae

    OpenAIRE

    Villarreal-Velásquez Tatiana Paola; Cortés-Daza César Camilo

    2012-01-01

    Introduction: bacterial meningitis is an infectious disease considered a medicalemergency. The timely management has an important impact on the evolution of thedisease. Streptococcus agalactiae, a major causative agent of severe infections innewborns can colonize different tissues, including the central nervous system.Case report: Male patient 47 years old from rural areas, with work activity as amilker of cattle, referred to tertiary care, with disorientation, neck stiffness, and grandmal se...

  3. Bacterial sex in dental plaque

    Directory of Open Access Journals (Sweden)

    Ingar Olsen

    2013-06-01

    Full Text Available Genes are transferred between bacteria in dental plaque by transduction, conjugation, and transformation. Membrane vesicles can also provide a mechanism for horizontal gene transfer. DNA transfer is considered bacterial sex, but the transfer is not parallel to processes that we associate with sex in higher organisms. Several examples of bacterial gene transfer in the oral cavity are given in this review. How frequently this occurs in dental plaque is not clear, but evidence suggests that it affects a number of the major genera present. It has been estimated that new sequences in genomes established through horizontal gene transfer can constitute up to 30% of bacterial genomes. Gene transfer can be both inter- and intrageneric, and it can also affect transient organisms. The transferred DNA can be integrated or recombined in the recipient's chromosome or remain as an extrachromosomal inheritable element. This can make dental plaque a reservoir for antimicrobial resistance genes. The ability to transfer DNA is important for bacteria, making them better adapted to the harsh environment of the human mouth, and promoting their survival, virulence, and pathogenicity.

  4. Cytochemical Differences in Bacterial Glycocalyx

    Science.gov (United States)

    Krautgartner, Wolf Dietrich; Vitkov, Ljubomir; Hannig, Matthias; Pelz, Klaus; Stoiber, Walter

    2005-02-01

    To examine new cytochemical aspects of the bacterial adhesion, a strain 41452/01 of the oral commensal Streptococcus sanguis and a wild strain of Staphylococcus aureus were grown with and without sucrose supplementation for 6 days. Osmiumtetraoxyde (OsO4), uranyl acetate (UA), ruthenium red (RR), cupromeronic blue (CB) staining with critical electrolytic concentrations (CECs), and the tannic acid-metal salt technique (TAMST) were applied for electron microscopy. Cytochemically, only RR-positive fimbriae in S. sanguis were visualized. By contrast, some types of fimbriae staining were observed in S. aureus glycocalyx: RR-positive, OsO4-positive, tannophilic and CB-positive with ceasing point at 0.3 M MgCl2. The CB staining with CEC, used for the first time for visualization of glycoproteins of bacterial glycocalyx, also reveals intacellular CB-positive substances-probably the monomeric molecules, that is, subunits forming the fimbriae via extracellular assembly. Thus, glycosylated components of the biofilm matrix can be reliably related to single cells. The visualization of intracellular components by CB with CEC enables clear distinction between S. aureus and other bacteria, which do not produce CB-positive substances. The small quantities of tannophilic substances found in S. aureus makes the use of TAMST for the same purpose difficult. The present work protocol enables, for the first time, a partial cytochemical differentiation of the bacterial glycocalyx.

  5. Chitosan-based Matrix, Used to Determine the Bacterial Lipopolysaccharide in Air

    Directory of Open Access Journals (Sweden)

    Dmitry M. Frolov

    2013-12-01

    Full Text Available The article describes the technology of chitosan-based matrix creation, and results of the study of its affine properties to bacterial lipopolysaccharide in aerosol dispersion. High degree of deacylation of polymer (over 97%, three-dimensional-porous structure, and multilayer packaging in analytical cartridge were the features of this matrix. Specified air volume, containing aerosol concentration of bacterial lipopolysaccharide, was passed through the glass cylinder with analytical container. The share of captured molecules ranged from 1.0% to 1.5%, demonstrating the efficiency of chitosan matrix. It is suitable for the creation of the devices for bacterial lipopolysaccharide detection in the air, based on the obtained matrix.

  6. Bacterial Communities in Rhizosphere of Maize Studied by T-RFLP

    Directory of Open Access Journals (Sweden)

    Ondreičková Katarína

    2014-12-01

    Full Text Available The terminal restriction fragment length polymorphism munities from different collecting places was evaluated was used to determine the bacterial diversity in rhizo- by principal component analysis. Results showed that sphere of maize (Zea mays L. collected from four sites the most different bacterial community originated from of experimental field plot in two dates of the vegetation marginal part of the experimental field plot collected in season (July and September. The 16S rRNA gene was September was caused probably by combination of the amplified from metagenomic DNA using universal eubac- marginal effect and drought before sampling date in Sep- terial primers and PCR products were digested separately tember. Other rhizosphere samples showed from moderate with three restriction enzymes. Significant differences in to small differences in the structure of the bacterial com- the number of terminal restriction fragments among rhi- munity. Nevertheless, significant differences among all zosphere samples and between sampling dates were not collected bacterial communities were not observed. detected (P < 0.05. Variation within the bacterial communities from different collecting places was evaluated by principal component analysis. Results showed that the most different bacterial community originated from marginal part of the experimental field plot collected in September was caused probably by combination of the marginal effect and drought before sampling date in September. Other rhizosphere samples showed from moderate to small differences in the structure of the bacterial community. Nevertheless, significant differences among all collected bacterial communities were not observed.

  7. Metatranscriptomics reveals overall active bacterial composition in caries lesions

    Directory of Open Access Journals (Sweden)

    Aurea Simón-Soro

    2014-10-01

    Full Text Available Background: Identifying the microbial species in caries lesions is instrumental to determine the etiology of dental caries. However, a significant proportion of bacteria in carious lesions have not been cultured, and the use of molecular methods has been limited to DNA-based approaches, which detect both active and inactive or dead microorganisms. Objective: To identify the RNA-based, metabolically active bacterial composition of caries lesions at different stages of disease progression in order to provide a list of potential etiological agents of tooth decay. Design: Non-cavitated enamel caries lesions (n=15 and dentin caries lesions samples (n=12 were collected from 13 individuals. RNA was extracted and cDNA was constructed, which was used to amplify the 16S rRNA gene. The resulting 780 bp polymerase chain reaction products were pyrosequenced using Titanium-plus chemistry, and the sequences obtained were used to determine the bacterial composition. Results: A mean of 4,900 sequences of the 16S rRNA gene with an average read length of 661 bp was obtained per sample, giving a comprehensive view of the active bacterial communities in caries lesions. Estimates of bacterial diversity indicate that the microbiota of cavities is highly complex, each sample containing between 70 and 400 metabolically active species. The composition of these bacterial consortia varied among individuals and between caries lesions of the same individuals. In addition, enamel and dentin lesions had a different bacterial makeup. Lactobacilli were found almost exclusively in dentin cavities. Streptococci accounted for 40% of the total active community in enamel caries, and 20% in dentin caries. However, Streptococcus mutans represented only 0.02–0.73% of the total bacterial community. Conclusions: The data indicate that the etiology of dental caries is tissue dependent and that the disease has a clear polymicrobial origin. The low proportion of mutans streptococci

  8. Phylogenetic characterization of the heterotrophic bacterial communities inhabiting a marine recirculating aquaculture system

    OpenAIRE

    Michaud, L; Lo Giudice, A; Troussellier, Marc; Smedile, F; Bruni, V.; Blancheton, J. P.

    2009-01-01

    Aims: The aim of the present work was to characterize the heterotrophic bacterial community of a marine recirculating aquaculture system (RAS). Methods and Results: An experimental RAS was sampled for the rearing water (RW) and inside the biofilter. Samples were analysed for bacterial abundances, community structure and composition by using a combination of culture-dependent and -independent techniques. The most represented species detected among biofilter clones was Pseudomonas stutzeri, whi...

  9. Bacterial adhesion and biofilms on surfaces

    Institute of Scientific and Technical Information of China (English)

    Trevor Roger Garrett; Manmohan Bhakoo; Zhibing Zhang

    2008-01-01

    Bacterial adhesion has become a significant problem in industry and in the domicile,and much research has been done for deeper understanding of the processes involved.A generic biological model of bacterial adhesion and population growth called the bacterial biofilm growth cycle,has been described and modified many times.The biofilm growth cycle encompasses bacterial adhesion at all levels,starting with the initial physical attraction of bacteria to a substrate,and ending with the eventual liberation of cell dusters from the biofilm matrix.When describing bacterial adhesion one is simply describing one or more stages of biofilm development,neglecting the fact that the population may not reach maturity.This article provides an overview of bacterial adhesion.cites examples of how bac-terial adhesion affects industry and summarises methods and instrumentation used to improve our understanding of the adhesive prop-erties of bacteria.

  10. Rapid bacterial identification using evanescent-waveguide oligonucleotide microarray classification.

    Science.gov (United States)

    Francois, Patrice; Charbonnier, Yvan; Jacquet, Jean; Utinger, Dominic; Bento, Manuela; Lew, Daniel; Kresbach, Gerhard M; Ehrat, Markus; Schlegel, Werner; Schrenzel, Jacques

    2006-06-01

    Bacterial identification relies primarily on culture-based methodologies and requires 48-72 h to deliver results. We developed and used i) a bioinformatics strategy to select oligonucleotide signature probes, ii) a rapid procedure for RNA labelling and hybridization, iii) an evanescent-waveguide oligoarray with exquisite signal/noise performance, and iv) informatics methods for microarray data analysis. Unique 19-mer signature oligonucleotides were selected in the 5'-end of 16s rDNA genes of human pathogenic bacteria. Oligonucleotides spotted onto a Ta(2)O(5)-coated microarray surface were incubated with chemically labelled total bacterial RNA. Rapid hybridization and stringent washings were performed before scanning and analyzing the slide. In the present paper, the eight most abundant bacterial pathogens representing >54% of positive blood cultures were selected. Hierarchical clustering analysis of hybridization data revealed characteristic patterns, even for closely related species. We then evaluated artificial intelligence-based approaches that outperformed conventional threshold-based identification schemes on cognate probes. At this stage, the complete procedure applied to spiked blood cultures was completed in less than 6 h. In conclusion, when coupled to optimal signal detection strategy, microarrays provide bacterial identification within a few hours post-sampling, allowing targeted antimicrobial prescription. PMID:16216356

  11. Differentiation of regions with atypical oligonucleotide composition in bacterial genomes

    Directory of Open Access Journals (Sweden)

    Reva Oleg N

    2005-10-01

    Full Text Available Abstract Background Complete sequencing of bacterial genomes has become a common technique of present day microbiology. Thereafter, data mining in the complete sequence is an essential step. New in silico methods are needed that rapidly identify the major features of genome organization and facilitate the prediction of the functional class of ORFs. We tested the usefulness of local oligonucleotide usage (OU patterns to recognize and differentiate types of atypical oligonucleotide composition in DNA sequences of bacterial genomes. Results A total of 163 bacterial genomes of eubacteria and archaea published in the NCBI database were analyzed. Local OU patterns exhibit substantial intrachromosomal variation in bacteria. Loci with alternative OU patterns were parts of horizontally acquired gene islands or ancient regions such as genes for ribosomal proteins and RNAs. OU statistical parameters, such as local pattern deviation (D, pattern skew (PS and OU variance (OUV enabled the detection and visualization of gene islands of different functional classes. Conclusion A set of approaches has been designed for the statistical analysis of nucleotide sequences of bacterial genomes. These methods are useful for the visualization and differentiation of regions with atypical oligonucleotide composition prior to or accompanying gene annotation.

  12. A simple and novel modification of comet assay for determination of bacteriophage mediated bacterial cell lysis.

    Science.gov (United States)

    Khairnar, Krishna; Sanmukh, Swapnil; Chandekar, Rajshree; Paunikar, Waman

    2014-07-01

    The comet assay is the widely used method for in vitro toxicity testing which is also an alternative to the use of animal models for in vivo testing. Since, its inception in 1984 by Ostling and Johansson, it is being modified frequently for a wide range of application. In spite of its wide applicability, unfortunately there is no report of its application in bacteriophages research. In this study, a novel application of comet assay for the detection of bacteriophage mediated bacterial cell lysis was described. The conventional methods in bacteriophage research for studying bacterial lysis by bacteriophages are plaque assay method. It is time consuming, laborious and costly. The lytic activity of bacteriophage devours the bacterial cell which results in the release of bacterial genomic material that gets detected by ethidium bromide staining method by the comet assay protocol. The objective of this study was to compare efficacy of comet assay with different assay used to study phage mediated bacterial lysis. The assay was performed on culture isolates (N=80 studies), modified comet assay appear to have relatively higher sensitivity and specificity than other assay. The results of the study showed that the application of comet assay can be an economical, time saving and less laborious alternative to conventional plaque assay for the detection of bacteriophage mediated bacterial cell lysis.

  13. A simple and novel modification of comet assay for determination of bacteriophage mediated bacterial cell lysis.

    Science.gov (United States)

    Khairnar, Krishna; Sanmukh, Swapnil; Chandekar, Rajshree; Paunikar, Waman

    2014-07-01

    The comet assay is the widely used method for in vitro toxicity testing which is also an alternative to the use of animal models for in vivo testing. Since, its inception in 1984 by Ostling and Johansson, it is being modified frequently for a wide range of application. In spite of its wide applicability, unfortunately there is no report of its application in bacteriophages research. In this study, a novel application of comet assay for the detection of bacteriophage mediated bacterial cell lysis was described. The conventional methods in bacteriophage research for studying bacterial lysis by bacteriophages are plaque assay method. It is time consuming, laborious and costly. The lytic activity of bacteriophage devours the bacterial cell which results in the release of bacterial genomic material that gets detected by ethidium bromide staining method by the comet assay protocol. The objective of this study was to compare efficacy of comet assay with different assay used to study phage mediated bacterial lysis. The assay was performed on culture isolates (N=80 studies), modified comet assay appear to have relatively higher sensitivity and specificity than other assay. The results of the study showed that the application of comet assay can be an economical, time saving and less laborious alternative to conventional plaque assay for the detection of bacteriophage mediated bacterial cell lysis. PMID:24681053

  14. Prevalent bacterial species and novel phylotypes in advanced noma lesions.

    Science.gov (United States)

    Paster, B J; Falkler Jr, W A; Enwonwu, C O; Idigbe, E O; Savage, K O; Levanos, V A; Tamer, M A; Ericson, R L; Lau, C N; Dewhirst, F E

    2002-06-01

    The purpose of this study was to determine the bacterial diversity in advanced noma lesions using culture-independent molecular methods. 16S ribosomal DNA bacterial genes from DNA isolated from advanced noma lesions of four Nigerian children were PCR amplified with universally conserved primers and spirochetal selective primers and cloned into Escherichia coli. Partial 16S rRNA sequences of approximately 500 bases from 212 cloned inserts were used initially to determine species identity or closest relatives by comparison with sequences of known species or phylotypes. Nearly complete sequences of approximately 1,500 bases were obtained for most of the potentially novel species. A total of 67 bacterial species or phylotypes were detected, 25 of which have not yet been grown in vitro. Nineteen of the species or phylotypes, including Propionibacterium acnes, Staphylococcus spp., and the opportunistic pathogens Stenotrophomonas maltophilia and Ochrobactrum anthropi were detected in more than one subject. Other known species that were detected included Achromobacter spp., Afipia spp., Brevundimonas diminuta, Capnocytophaga spp., Cardiobacterium sp., Eikenella corrodens, Fusobacterium spp., Gemella haemoylsans, and Neisseria spp. Phylotypes that were unique to noma infections included those in the genera Eubacterium, Flavobacterium, Kocuria, Microbacterium, and Porphyromonas and the related Streptococcus salivarius and genera Sphingomonas and TREPONEMA: Since advanced noma lesions are infections open to the environment, it was not surprising to detect species not commonly associated with the oral cavity, e.g., from soil. Several species previously implicated as putative pathogens of noma, such as spirochetes and Fusobacterium spp., were detected in at least one subject. However, due to the limited number of available noma subjects, it was not possible at this time to associate specific species with the disease.

  15. Detect ground motion effects on the trajectory at ATF2

    CERN Document Server

    Rénier, Yves; Garcia, Rogelio

    2011-01-01

    The Accelerator Test Facility 2 (ATF2) commissioning group aims to demonstrate the feasibility of the Beam Delivery System (BDS) of the next linear colliders (ILC and CLIC) as well as to define and to test the tunning methods. As the design vertical beam sizes of the linear colliders are about few nanometers, the stability of the trajectory as well as the control of the aberrations are very critical. The magnet displacements induced by ground motion are large enough for CLIC to perturb the beam stability above requirements. It is planned to measure the displacement of the magnets and implement a feed-forward correcting the effects on the beam trajectory with correctors (dipoles). This article studies the possibility to detect ground motion effects on the beam trajectory at ATF2. Characteristics of the ground motion at ATF2 are presented, the effects of the magnet displacements on the beam trajectory are simulated and an algorithm predicting the induced trajectory fluctuations is evaluated. After the estimated...

  16. High performance liquid chromatography with immobilized Ru(bpy)32+-KMn04 chemiluminescence detection and its application in metabolism of repaglinide in pig liver microsomes

    Institute of Scientific and Technical Information of China (English)

    Ai Hua Fu; Zhu Jun Zhang; Li Li Chen; Xiao Ming Zhang; Pan Xue

    2011-01-01

    A novel high performance liquid chromatography-chemiluminescence (HPLC-CL) method for investigation of in vitro metabolism of repaglinide in pig liver microsomes with microdialysis sampling technique was developed. The chromatographic separation was performed on a Hypersil BDS-C18 column with an isocratic mobile phase consisting of methanol and 0.01 mol/L KH2PO4 (pH 3.0) (volume ratio 75:25) at a flow rate of 1.0 mL/min. The detection was based on the chemiluminescence reaction of repaglinide with acidic potassium permanganate (KMnO4) and tris (2,2'-bipyridyl)ruthenium(III) (Ru(bpy)33+), which was immobilized on the cationic ion-exchange resin for obtaining high sensitivity and reducing consumption of expensive reagent.

  17. Bacterial Communities Associated with Different Anthurium andraeanum L. Plant Tissues

    Science.gov (United States)

    Sarria-Guzmán, Yohanna; Chávez-Romero, Yosef; Gómez-Acata, Selene; Montes-Molina, Joaquín Adolfo; Morales-Salazar, Eleacin; Dendooven, Luc; Navarro-Noya, Yendi E.

    2016-01-01

    Plant-associated microbes have specific beneficial functions and are considered key drivers for plant health. The bacterial community structure of healthy Anthurium andraeanum L. plants was studied by 16S rRNA gene pyrosequencing associated with different plant parts and the rhizosphere. A limited number of bacterial taxa, i.e., Sinorhizobium, Fimbriimonadales, and Gammaproteobacteria HTCC2089 were enriched in the A. andraeanum rhizosphere. Endophytes were more diverse in the roots than in the shoots, whereas all shoot endophytes were found in the roots. Streptomyces, Flavobacterium succinicans, and Asteroleplasma were only found in the roots, Variovorax paradoxus only in the stem, and Fimbriimonas 97%-OTUs only in the spathe, i.e., considered specialists, while Brevibacillus, Lachnospiraceae, Pseudomonas, and Pseudomonas pseudoalcaligenes were generalist and colonized all plant parts. The anaerobic diazotrophic bacteria Lachnospiraceae, Clostridium sp., and Clostridium bifermentans colonized the shoot system. Phylotypes belonging to Pseudomonas were detected in the rhizosphere and in the substrate (an equiproportional mixture of soil, cow manure, and peat), and dominated the endosphere. Pseudomonas included nine 97%-OTUs with different patterns of distribution and phylogenetic affiliations with different species. P. pseudoalcaligenes and P. putida dominated the shoots, but were also found in the roots and rhizosphere. P. fluorescens was present in all plant parts, while P. resinovorans, P. denitrificans, P. aeruginosa, and P. stutzeri were only detected in the substrate and rhizosphere. The composition of plant-associated bacterial communities is generally considered to be suitable as an indicator of plant health. PMID:27524305

  18. Small intestinal bacterial overgrowth in patients with chronic hepatitis C

    Directory of Open Access Journals (Sweden)

    K. V. Zhdanov

    2011-01-01

    Full Text Available In order to estimate the frequency of detection of bacterial overgrowth syndrome in patients with chronic hepatitis C, find a possible relationship between development dysbiotic changes in the small intestine and over chronic hepatitis C were examined 80 patients (68 males and 12 females. In addition to standard laboratory tests for all patients was performed hydrogen breath test with a load of lactulose and fibrogastroduodenoscopy and hepatic biopsy with subsequent histological examination of biopsy. It was found that bacterial overgrowth syndrome, according to the hydrogen breath test detected 40% of patients with chronic hepatitis C, and the severity of it increases with the progression of the pathological process in the liver tissue. urthermore, in patients with endoscopic signs of catarrhal duodenitis according fibrogastroduodenoscopy, the level of molecular hydrogen when the hydrogen breath test at the appropriate stages of measurement was significantly lower, which may be due to the lack of saccharolytic and / or the predominance of proteolytic flora in the development of bacterial overgrowth syndrome.

  19. Nest Bacterial Environment Affects Microbiome of Hoopoe Eggshells, but Not That of the Uropygial Secretion

    Science.gov (United States)

    Martínez-García, Ángela; Martín-Vivaldi, Manuel; Rodríguez-Ruano, Sonia M.; Peralta-Sánchez, Juan Manuel; Valdivia, Eva; Soler, Juan J.

    2016-01-01

    The study of associations between symbiotic bacterial communities of hosts and those of surrounding environments would help to understand how bacterial assemblages are acquired, and how they are transmitted from one to another location (i.e. symbiotic bacteria acquisition by hosts). Hoopoes (Upupa epops) smear their eggshells with uropygial secretion (oily secretion produced in their uropygial gland) that harbors antibiotic producing bacteria. Trying to elucidate a possible role of nest material and cloaca microbiota in determining the bacterial community of the uropygial gland and the eggshells of hoopoes, we characterized bacterial communities of nest material, cloaca, uropygial gland and eggshells by the ARISA fingerprinting. Further, by adding material with scarce bacteria and antimicrobial properties, we manipulated the bacterial community of nest material and thus tested experimentally its effects on the microbiomes of the uropygial secretion and of the eggshells. The experiment did not influence the microbiome of the uropygial secretion of females, but affected the community established on eggshells. This is the first experimental evidence indicating that nest material influences the bacterial community of the eggshells and, therefore, probability of embryo infection. Some of the bacterial strains detected in the secretion were also in the bacterial communities of the nest material and of cloaca, but their occurrence within nests was not associated, which suggests that bacterial environments of nest material and cloaca are not sources of symbiotic bacteria for the gland. These results do not support a role of nest environments of hoopoes as reservoirs of symbiotic bacteria. We discuss possible scenarios explaining bacterial acquisition by hoopoes that should be further explored. PMID:27409772

  20. Identifying Pathogenicity Islands in Bacterial Pathogenomics Using Computational Approaches

    Directory of Open Access Journals (Sweden)

    Dongsheng Che

    2014-01-01

    Full Text Available High-throughput sequencing technologies have made it possible to study bacteria through analyzing their genome sequences. For instance, comparative genome sequence analyses can reveal the phenomenon such as gene loss, gene gain, or gene exchange in a genome. By analyzing pathogenic bacterial genomes, we can discover that pathogenic genomic regions in many pathogenic bacteria are horizontally transferred from other bacteria, and these regions are also known as pathogenicity islands (PAIs. PAIs have some detectable properties, such as having different genomic signatures than the rest of the host genomes, and containing mobility genes so that they can be integrated into the host genome. In this review, we will discuss various pathogenicity island-associated features and current computational approaches for the identification of PAIs. Existing pathogenicity island databases and related computational resources will also be discussed, so that researchers may find it to be useful for the studies of bacterial evolution and pathogenicity mechanisms.

  1. [Bacterial genomics and metagenomics: clinical applications and medical relevance].

    Science.gov (United States)

    Diene, S M; Bertelli, C; Pillonel, T; Schrenzel, J; Greub, G

    2014-11-12

    New sequencing technologies provide in a short time and at low cost high amount of genomic sequences useful for applications such as: a) development of diagnostic PCRs and/or serological tests; b) detection of virulence factors (virulome) or genes/SNPs associated with resistance to antibiotics (resistome) and c) investigation of transmission and dissemination of bacterial pathogens. Thus, bacterial genomics of medical importance is useful to clinical microbiologists, to infectious diseases specialists as well as to epidemiologists. Determining the microbial composition of a sample by metagenomics is another application of new sequencing technologies, useful to understand the impact of bacteria on various non-infectious diseases such as obesity, asthma, or diabetes. Genomics and metagenomics will likely become a specialized diagnostic analysis.

  2. Periodontal diseases as bacterial infection

    Directory of Open Access Journals (Sweden)

    A. Bascones Martínez

    2005-12-01

    Full Text Available The periodontal disease is conformed by a group of illnesses affecting the gums and dental support structures. They are caused by certain bacteria found in the bacterial plaque. These bacteria are essential to the onset of illness; however, there are predisposing factors in both the host and the microorganisms that will have an effect on the pathogenesis of the illness. Periodontopathogenic bacterial microbiota is needed, but by itself, it is not enough to cause the illness, requiring the presence of a susceptible host. These diseases have been classified as gingivitis, when limited to the gums, and periodontitis, when they spread to deeper tissues. Classification of periodontal disease has varied over the years.The one used in this work was approved at the International Workshop for a Classification of Periodontal Diseases and Conditions, held in 1999. This study is an overview of the different periodontal disease syndromes. Later, the systematic use of antibiotic treatment consisting of amoxicillin, amoxicillinclavulanic acid, and metronidazole as first line coadjuvant treatment of these illnesses will be reviewed.

  3. BACTERIAL DESEASES IN SEA FISH

    Directory of Open Access Journals (Sweden)

    Ivančica Strunjak-Perović

    1997-10-01

    Full Text Available With development of the fish culturing in the sea, the interest in their health also increased. The reason for this are diseases or rather mortality that occur in such controlled cultures and cause great economic losses. By growing large quantities of fish in rather small species, natural conditions are changed, so fish is more sensitive and prone to infection agents (viruses, bacteria, parasites. Besides, a large fish density in the cultural process accelerates spreading if the diseases, but also enables a better perception of them. In wild populations sick specimen very quickly become predator’s prey, witch makes it difficult to note any pathological changes in such fish. There are lots of articles on viral, bacterial and parasitic diseases nowdays, but this work deals exclusively with bacterial deseases that occur in the controlled sea cultures (vibriosis, furunculosis, pastherelosis, nocardiosis, mycobaceriosis, edwardsielosis, yersiniosis, deseases caused by bacteria of genera Flexibacter, Pseudomonas, Aeromonas, Streptococus and bacteria nephryithis. Yet, the knowledge of these deseases vary, depending on wether a fish species is being cultured for a longer period of time or is only being introduced in the controlled culture.

  4. Bioinformatic Comparison of Bacterial Secretomes

    Institute of Scientific and Technical Information of China (English)

    Catharine Song; Aseem Kumar; Mazen Saleh

    2009-01-01

    The rapid increasing number of completed bacterial genomes provides a good op-portunity to compare their proteomes. This study was undertaken to specifically compare and contrast their secretomes-the fraction of the proteome with pre-dicted N-terminal signal sequences, both type Ⅰ and type Ⅱ. A total of 176 theoreti-cal bacterial proteomes were examined using the ExProt program. Compared with the Gram-positives, the Gram-negative bacteria were found, on average, to con-tain a larger number of potential Sec-dependent sequences. In the Gram-negative bacteria but not in the others, there was a positive correlation between proteome size and secretome size, while there was no correlation between secretome size and pathogenicity. Within the Gram-negative bacteria, intracellular pathogens were found to have the smallest secretomes. However, the secretomes of certain bacte-ria did not fit into the observed pattern. Specifically, the secretome of Borrelia burgdoferi has an unusually large number of putative lipoproteins, and the signal peptides of mycoplasmas show closer sequence similarity to those of the Gram-negative bacteria. Our analysis also suggests that even for a theoretical minimal genome of 300 open reading frames, a fraction of this gene pool (up to a maximum of 20%) may code for proteins with Sec-dependent signal sequences.

  5. Bacterial Culture of Neonatal Sepsis

    Directory of Open Access Journals (Sweden)

    AH Movahedian

    2006-08-01

    Full Text Available Neonatal bacterial sepsis is one of the major cause of morbidity and mortality in neonates. This retrospective study was performed to determine the incidence of bacterial sepsis with focus on Gram negative organisms in neonates admitted at Beheshti Hospital in Kashan, during a 3-yr period, from September 2002 to September 2005. Blood culture was performed on all neonates with risk factors or signs of suggestive sepsis. Blood samples were cultured using brain heart infusion (BHI broth according to standard method. From the 1680 neonates 36% had positive blood culture for Pseudomans aeruginosa, 20.7% for Coagulase negative Staphylococci, and 17% for Klebsiella spp. Gram-negative organisms accounted for 72.1% of all positive cultures. The overall mortality rate was 19.8% (22 /111 of whom 63.6% (14 /22 were preterm. Pseudomona aeruginosa and Klebsiella spp. showed a high degree of resistance to commonly used antibiotics (ampicillin, gentamicin as well as third generation cephalosporins. Continued local surveillance studies are urged to monitor emerging antimicrobial resistance and to guide interventions to minimize its occurrence.

  6. Immunization by a bacterial aerosol.

    Science.gov (United States)

    Garcia-Contreras, Lucila; Wong, Yun-Ling; Muttil, Pavan; Padilla, Danielle; Sadoff, Jerry; Derousse, Jessica; Germishuizen, Willem Andreas; Goonesekera, Sunali; Elbert, Katharina; Bloom, Barry R; Miller, Rich; Fourie, P Bernard; Hickey, Anthony; Edwards, David

    2008-03-25

    By manufacturing a single-particle system in two particulate forms (i.e., micrometer size and nanometer size), we have designed a bacterial vaccine form that exhibits improved efficacy of immunization. Microstructural properties are adapted to alter dispersive and aerosol properties independently. Dried "nanomicroparticle" vaccines possess two axes of nanoscale dimensions and a third axis of micrometer dimension; the last one permits effective micrometer-like physical dispersion, and the former provides alignment of the principal nanodimension particle axes with the direction of airflow. Particles formed with this combination of nano- and micrometer-scale dimensions possess a greater ability to aerosolize than particles of standard spherical isotropic shape and of similar geometric diameter. Here, we demonstrate effective application of this biomaterial by using the live attenuated tuberculosis vaccine bacille Calmette-Guérin (BCG). Prepared as a spray-dried nanomicroparticle aerosol, BCG vaccine exhibited high-efficiency delivery and peripheral lung targeting capacity from a low-cost and technically simple delivery system. Aerosol delivery of the BCG nanomicroparticle to normal guinea pigs subsequently challenged with virulent Mycobacterium tuberculosis significantly reduced bacterial burden and lung pathology both relative to untreated animals and to control animals immunized with the standard parenteral BCG. PMID:18344320

  7. Conjunctival sac bacterial flora isolated prior to cataract surgery

    Directory of Open Access Journals (Sweden)

    Suto C

    2012-01-01

    a history of allergic conjunctivitis. Methicillin-resistant coagulase-negative staphylococci showed a significantly higher detection rate in diabetic patients than nondiabetic patients (20.3% versus 7.0%, P < 0.05. The percentage of all isolates resistant to levofloxacin, cefmenoxime, and tobramycin was 14.0%, 15.2%, and 17.9%, respectively, with no significant differences among these drugs.Conclusion: The high bacterial isolation rate in patients >60 years old and the high methicillin-resistant coagulase-negative staphylococci isolation rate in patients with diabetes are important to consider for prevention of perioperative infections.Keywords: endophthalmitis, cataract surgery, conjunctival sac, bacterial flora, diabetes mellitus

  8. Relationship between bacterial infection and evaluation using a laser fluorescence device, DIAGNOdent.

    Science.gov (United States)

    Iwami, Yukiteru; Shimizu, Ayako; Narimatsu, Masahiro; Hayashi, Mikako; Takeshige, Fumio; Ebisu, Shigeyuki

    2004-10-01

    The aim of this in vitro study was to investigate the relationship between bacterial infections in carious dentin when detected by two different methods -- polymerase chain reaction (PCR), and a laser fluorescence device, DIAGNOdent. Dentin was removed every 300 micro m in the direction of the pulp chamber in 10 extracted molars with occlusal dentin caries and 3 extracted sound molars. Dentin surfaces were evaluated using DIAGNOdent, and dentinal tissue samples were removed by using a round bur before and after each removal. Bacterial DNA in the dentinal tissues was detected by PCR, using primers based on the nucleotide sequence of a conserved region of the 16S rDNA, and yielded a PCR product of 466 bp. The rates of bacterial detection increased as the DIAGNOdent values increased. In the 10 specimens, the lowest DIAGNOdent value at which bacteria were detected was 15.6; at DIAGNOdent values below 15.6, no bacteria were detected. The results of a receiver operating characteristic (ROC) curve for the DIAGNOdent values showed that the area under the ROC curve was 0.91. This study clarified the relationship between the DIAGNOdent values of dentin caries and the rates of bacterial detection.

  9. Remodeling bacterial polysaccharides by metabolic pathway engineering

    OpenAIRE

    Yi, Wen; Liu, Xianwei; Li, Yanhong; Li, Jianjun; Xia, Chengfeng; Zhou, Guangyan; Zhang, Wenpeng; Zhao, Wei; Chen, Xi; Wang, Peng George

    2009-01-01

    Introducing structural modifications into biomolecules represents a powerful approach to dissect their functions and roles in biological processes. Bacterial polysaccharides, despite their rich structural information and essential roles in bacterium-host interactions and bacterial virulence, have largely been unexplored for in vivo structural modifications. In this study, we demonstrate the incorporation of a panel of monosaccharide analogs into bacterial polysaccharides in a highly homogenou...

  10. Effect of aerosolization on subsequent bacterial survival.

    OpenAIRE

    Walter, M V; Marthi, B; Fieland, V P; Ganio, L M

    1990-01-01

    To determine whether aerosolization could impair bacterial survival, Pseudomonas syringae and Erwinia herbicola were aerosolized in a greenhouse, the aerosol was sampled at various distances from the site of release by using all-glass impingers, and bacterial survival was followed in the impingers for 6 h. Bacterial survival subsequent to aerosolization of P. syringae and E. herbicola was not impaired 1 m from the site of release. P. syringae aerosolized at 3 to 15 m from the site of release ...

  11. Drag Reduction of Bacterial Cellulose Suspensions

    OpenAIRE

    Ogata, Satoshi; Numakawa, Tetsuya; Kubo, Takuya

    2010-01-01

    Drag reduction due to bacterial cellulose suspensions with small environmental loading was investigated. Experiments were carried out by measuring the pressure drop in pipe flow. It was found that bacterial cellulose suspensions give rise to drag reduction in the turbulent flow range. We observed a maximum drag reduction ratio of 11% and found that it increased with the concentration of the bacterial cellulose suspension. However, the drag reduction effect decreased in the presence of mechani...

  12. Drag Reduction of Bacterial Cellulose Suspensions

    OpenAIRE

    Satoshi Ogata; Tetsuya Numakawa; Takuya Kubo

    2011-01-01

    Drag reduction due to bacterial cellulose suspensions with small environmental loading was investigated. Experiments were carried out by measuring the pressure drop in pipe flow. It was found that bacterial cellulose suspensions give rise to drag reduction in the turbulent flow range. We observed a maximum drag reduction ratio of 11% and found that it increased with the concentration of the bacterial cellulose suspension. However, the drag reduction effect decreased in the presence of mechani...

  13. Endosymbiont dominated bacterial communities in a dwarf spider.

    Directory of Open Access Journals (Sweden)

    Bram Vanthournout

    Full Text Available The microbial community of spiders is little known, with previous studies focussing primarily on the medical importance of spiders as vectors of pathogenic bacteria and on the screening of known cytoplasmic endosymbiont bacteria. These screening studies have been performed by means of specific primers that only amplify a selective set of endosymbionts, hampering the detection of unreported species in spiders. In order to have a more complete overview of the bacterial species that can be present in spiders, we applied a combination of a cloning assay, DGGE profiling and high-throughput sequencing on multiple individuals of the dwarf spider Oedothorax gibbosus. This revealed a co-infection of at least three known (Wolbachia, Rickettsia and Cardinium and the detection of a previously unreported endosymbiont bacterium (Rhabdochlamydia in spiders. 16S rRNA gene sequences of Rhabdochlamydia matched closely with those of Candidatus R. porcellionis, which is currently only reported as a pathogen from a woodlouse and with Candidatus R. crassificans reported from a cockroach. Remarkably, this bacterium appears to present in very high proportions in one of the two populations only, with all investigated females being infected. We also recovered Acinetobacter in high abundance in one individual. In total, more than 99% of approximately 4.5M high-throughput sequencing reads were restricted to these five bacterial species. In contrast to previously reported screening studies of terrestrial arthropods, our results suggest that the bacterial communities in this spider species are dominated by, or even restricted to endosymbiont bacteria. Given the high prevalence of endosymbiont species in spiders, this bacterial community pattern could be widespread in the Araneae order.

  14. Diverse roles of endoplasmic reticulum stress sensors in bacterial infection.

    Science.gov (United States)

    Pillich, Helena; Loose, Maria; Zimmer, Klaus-Peter; Chakraborty, Trinad

    2016-12-01

    Bacterial infection often leads to cellular damage, primarily marked by loss of cellular integrity and cell death. However, in recent years, it is being increasingly recognized that, in individual cells, there are graded responses collectively termed cell-autonomous defense mechanisms that induce cellular processes designed to limit cell damage, enable repair, and eliminate bacteria. Many of these responses are triggered not by detection of a particular bacterial effector or ligand but rather by their effects on key cellular processes and changes in homeostasis induced by microbial effectors when recognized. These in turn lead to a decrease in essential cellular functions such as protein translation or mitochondrial respiration and the induction of innate immune responses that may be specific to the cellular deficit induced. These processes are often associated with specific cell compartments, e.g., the endoplasmic reticulum (ER). Under non-infection conditions, these systems are generally involved in sensing cellular stress and in inducing and orchestrating the subsequent cellular response. Thus, perturbations of ER homeostasis result in accumulation of unfolded proteins which are detected by ER stress sensors in order to restore the normal condition. The ER is also important during bacterial infection, and bacterial effectors that activate the ER stress sensors have been discovered. Increasing evidence now indicate that bacteria have evolved strategies to differentially activate different arms of ER stress sensors resulting in specific host cell response. In this review, we will describe the mechanisms used by bacteria to activate the ER stress sensors and discuss their role during infection. PMID:26883353

  15. Evaluation of PCR based assays for the improvement of proportion estimation of bacterial and viral pathogens in diarrheal surveillance

    Directory of Open Access Journals (Sweden)

    Hongxia eGuan

    2016-03-01

    Full Text Available AbstractDiarrhea can be caused by a variety of bacterial, viral and parasitic organisms. Laboratory diagnosis is essential in the pathogen-specific burden assessment. In the pathogen spectrum monitoring in the diarrheal surveillance, culture methods are commonly used for the bacterial pathogens’ detection whereas nucleic acid based amplification, the non-cultural methods are used for the viral pathogens. Different methodology may cause the inaccurate pathogen spectrum for the bacterial pathogens because of their different culture abilities with the different media, and for the comparison of bacterial vs. viral pathogens. The application of nucleic acid-based methods in the detection of viral and bacterial pathogens will likely increase the number of confirmed positive diagnoses, and will be comparable since all pathogens will be detected based on the same nucleic acid extracts from the same sample. In this study, bacterial pathogens, including diarrheagenic Escherichia coli (DEC, Salmonella spp., Shigella spp., Vibrio parahaemolyticus and V. cholerae, were detected in 334 diarrheal samples by PCR-based methods using nucleic acid extracted from stool samples and associated enrichment cultures. A protocol was established to facilitate the consistent identification of bacterial pathogens in diarrheal patients. Five common enteric viruses were also detected by RT-PCR, including rotavirus, sapovirus, norovirus (I and II, human astrovirus, and enteric adenovirus. Higher positive rates were found for the bacterial pathogens, showing the lower proportion estimation if only using culture methods. This application will improve the quality of bacterial diarrheagenic pathogen survey, providing more accurate information pertaining to the pathogen spectrum associated with finding of food safety problems and disease burden evaluation.

  16. Bacterial antigen detection in cerebrospinal fluid by the latex agglutination test Detecção de antígenos bacterianos no líquido cefalorraquidiano através do teste de aglutinação de latex

    Directory of Open Access Journals (Sweden)

    Ilka Maria Landgraf

    1995-06-01

    Full Text Available Eighty purulent cerebrospinal fluid (CSF samples from patients with clinical evidence of meningitis were studied using the Directigen latex agglutination (LA kit to determine the presence of bacterial antigen in CSF. The results showed a better diagnostic performance of the LA test than bacterioscopy by Gram stain, culture and counterimmunoelectrophoresis (CIE, as far as Neisseria meningitidis groups B and C, and Haemophilus influenzae type b are concerned, and a better performance than bacterioscopy and culture considering Streptococcus pneumoniae. Comparison of the results with those of culture showed that the LA test had the highest sensitivity for the Neisseria meningitidis group C. Comparing the results with those of CIE, the highest levels of sensitivity were detected for N. meningitidis groups B and C. Regarding specificity, fair values were obtained for all organisms tested. The degree of K agreement when the LA test was compared with CIE exhibited better K indices of agreement for N. meningitidis groups B and C.Oitenta amostras purulentas de líquido cefalorraquidiano (LCR de pacientes com evidência clínica de meningite foram estudadas empregando-se Kit Directigen de aglutinação de latex (AL para demonstrar antígeno bacteriano no LCR. Os resultados mostraram que o teste de AL apresentou melhor desempenho diagnóstico do que bacterioscopia através da coloração de Gram, cultura e imunoeletroforese cruzada (IEC em relação à Neisseria meningitidis grupos B e C, e ao Haemophilus influenzae tipo b, e melhor do que coloração de Gram e cultura quando Streptococcus pneumoniae foi avaliado. A comparação dos resultados com os de cultura mostrou o maior nível de sensibilidade considerando-se N. meningitidis grupo C. Quanto à especificidade, os valores foram satisfatórios para todos os microrganismos testados. O grau de concordância K em relação à IEC exibiu melhores índices K de concordância para N. meningitidis grupos B e C.

  17. Bacterial successions in the Broiler Gastrointestinal tract

    DEFF Research Database (Denmark)

    Ranjitkar, Samir; Lawley, Blair; Tannock, Gerald;

    2016-01-01

    of crop, gizzard, ileum and ceca in relation to the feeding strategy and age (8, 15, 22, 25, 29 and 36 days). Of the four dietary treatments, bacterial diversity was analyzed for MBF and CKMS-30 by 454-pyrosequencing of 16S rRNA gene. Since there was no significant influence of diets on bacterial...... diversity, data were pooled for downstream analysis. With increasing age, a clear succession of bacterial communities and an increased bacterial diversity was observed. Lactobacillaceae (mainly Lactobacillus) represented most of the Firmicutes at all ages and in all segments of the gut except the ceca...

  18. Phylogenetic analysis of bacterial community in deep-sea sediment from the western Pacific "warm pool"

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A depth profile of bacterial community structure in one deep-sea sediment core of the western Pacific "warm pool" (WP) was investigated and compared with that in a sediment sample from the eastern Pacific (EP) by phylogenetic analysis of 16S rDNA fragments.Five bacterial 16S rDNA clone libraries were constructed, and t33 clones with different restriction fragment length polymorphism(RFLP) patterns were sequenced. A phylogenetic analysis of these sequences revealed that the bacterial diversity in a sample from the WP was more abundant than that in the EP sample. The bacterial population in the sediment core of WP was composed of eight major lineages of the domain bacteria. Among them the γ-Proteobacteria was the predominant and most diverse group in each section of WP sediment core, followed by the α-Proteobacteria. The genus Colwellia belonging to γ-Proteobacteria was predominant in this sample.The shift of bacterial communities among different sections of the WP sediment core was δ-, ε-Proteobacteria, and Cytopahga-Flexibacteria-Bacteroides (CFB) group. The ratios between them in the bacterial communities all showed inversely proportional to the depth of sediment. The sequences related to sulphate reducing bacteria (SRB) were detected in every section. The bacterial community structure in this sediment core might be related to the environmental characteristics of the surface seawater of the western Pacific WP.

  19. Differences in activity profile of bacterial cultures studied by dynamic speckle patterns

    Science.gov (United States)

    Ramírez-Miquet, E. E.; Otero, I.; Rodríguez, D.; Darias, J. G.; Combarro, A. M.; Contreras, O. R.

    2013-02-01

    We outline the main differences in the activity profile of bacterial cultures studied by dynamic laser speckle (or biospeckle) patterns. The activity is detected in two sorts of culture mediums. The optical setup and the experimental procedure are presented. The experimentally obtained images are processed by the temporal difference method and a qualitative assessment is made with the time history of speckle patterns of the sample. The main differences are studied after changing the culture medium composition. We conclude that the EC medium is suitable to detect the E. coli bacterial presence in early hours and that Mueller Hinton agar delays some additional hours to make possible the assessment of bacteria in time.

  20. The utility of the polymerase chain reaction assay for aetiologic definition of unspecified bacterial meningitis cases

    Directory of Open Access Journals (Sweden)

    Mari Tuyama

    2008-03-01

    Full Text Available Most patients with acute suppurative meningitis are otherwise healthy individuals with regard to immune mechanisms against invasive bacterial disease. This medical emergency is among the most dramatic and potentially ravaging diseases that affect humans, particularly young children. The illness often strikes suddenly, and can either result in death or leave the survivors with significant neurological dysfunctions. The demonstration of a bacterial aetiology is necessary for decisions regarding treatment and prophylaxis. Conventional bacteriological methods frequently fail to identify an agent, as a result of administration of antibiotics or delayed lumbar punctures. We investigated the major aetiologic sources of unspecified bacterial meningitis cases (G00.9, ISCD-10 by polymerase chain reaction (PCR-based identification of Neisseria meningitidis (crgA, Streptococcus pneumoniae (ply and Haemophilus influenzae (bexA in cerebrospinal fluid samples. The multiplex PCR detected N. meningitidis in 92%, S. pneumoniae in 4% and H. influenzae in 1% of the 192 clinical samples assayed; 3% were negative for all three DNA targets. Bacterial DNA detection was found to be a valuable adjunct to enhance bacterial meningitis surveillance when the yield of specimens by culture is reduced. The implementation of PCR assays as a diagnostic procedure in Public Health Laboratories is perceived to be a significant advance in the investigation of bacterial meningitis.

  1. Determination of bacterial activity by use of an evanescent-wave fiber-optic sensor.

    Science.gov (United States)

    John, M Shelly; Kishen, Anil; Sing, Lim Chu; Asundi, Anand

    2002-12-01

    A novel technique based on fiber-optic evanescent-wave spectroscopy is proposed for the detection of bacterial activity in human saliva. The sensor determines th e specific concentration of Streptococcus mutans in saliva, which is a major causative factor in dental caries. In this design, one prepares the fiber-optic bacterial sensor by replacing a portion of the cladding region of a multimode fiber with a dye-encapsulated xerogel, using the solgel technique. The exponential decay of the evanescent wave at the core-cladding interface of a multimode fiber is utilized for the determination of bacterial activity in saliva. The acidogenic profile of Streptococcus mutans is estimated by use of evanescent-waveabsorption spectra at various levels of bacterial activity. PMID:12477126

  2. Determination of bacterial activity by use of an evanescent-wave fiber-optic sensor

    Science.gov (United States)

    John, M. Shelly; Kishen, Anil; Sing, Lim Chu; Asundi, Anand

    2002-12-01

    A novel technique based on fiber-optic evanescent-wave spectroscopy is proposed for the detection of bacterial activity in human saliva. The sensor determines the specific concentration of Streptococcus mutans in saliva, which is a major causative factor in dental caries. In this design, one prepares the fiber-optic bacterial sensor by replacing a portion of the cladding region of a multimode fiber with a dye-encapsulated xerogel, using the solgel technique. The exponential decay of the evanescent wave at the core-cladding interface of a multimode fiber is utilized for the determination of bacterial activity in saliva. The acidogenic profile of Streptococcus mutans is estimated by use of evanescent-wave absorption spectra at various levels of bacterial activity.

  3. One bacterial cell, one complete genome.

    Directory of Open Access Journals (Sweden)

    Tanja Woyke

    Full Text Available While the bulk of the finished microbial genomes sequenced to date are derived from cultured bacterial and archaeal representatives, the vast majority of microorganisms elude current culturing attempts, severely limiting the ability to recover complete or even partial genomes from these environmental species. Single cell genomics is a novel culture-independent approach, which enables access to the genetic material of an individual cell. No single cell genome has to our knowledge been closed and finished to date. Here we report the completed genome from an uncultured single cell of Candidatus Sulcia muelleri DMIN. Digital PCR on single symbiont cells isolated from the bacteriome of the green sharpshooter Draeculacephala minerva bacteriome allowed us to assess that this bacteria is polyploid with genome copies ranging from approximately 200-900 per cell, making it a most suitable target for single cell finishing efforts. For single cell shotgun sequencing, an individual Sulcia cell was isolated and whole genome amplified by multiple displacement amplification (MDA. Sanger-based finishing methods allowed us to close the genome. To verify the correctness of our single cell genome and exclude MDA-derived artifacts, we independently shotgun sequenced and assembled the Sulcia genome from pooled bacteriomes using a metagenomic approach, yielding a nearly identical genome. Four variations we detected appear to be genuine biological differences between the two samples. Comparison of the single cell genome with bacteriome metagenomic sequence data detected two single nucleotide polymorphisms (SNPs, indicating extremely low genetic diversity within a Sulcia population. This study demonstrates the power of single cell genomics to generate a complete, high quality, non-composite reference genome within an environmental sample, which can be used for population genetic analyzes.

  4. One Bacterial Cell, One Complete Genome

    Energy Technology Data Exchange (ETDEWEB)

    Woyke, Tanja; Tighe, Damon; Mavrommatis, Konstantinos; Clum, Alicia; Copeland, Alex; Schackwitz, Wendy; Lapidus, Alla; Wu, Dongying; McCutcheon, John P.; McDonald, Bradon R.; Moran, Nancy A.; Bristow, James; Cheng, Jan-Fang

    2010-04-26

    While the bulk of the finished microbial genomes sequenced to date are derived from cultured bacterial and archaeal representatives, the vast majority of microorganisms elude current culturing attempts, severely limiting the ability to recover complete or even partial genomes from these environmental species. Single cell genomics is a novel culture-independent approach, which enables access to the genetic material of an individual cell. No single cell genome has to our knowledge been closed and finished to date. Here we report the completed genome from an uncultured single cell of Candidatus Sulcia muelleri DMIN. Digital PCR on single symbiont cells isolated from the bacteriome of the green sharpshooter Draeculacephala minerva bacteriome allowed us to assess that this bacteria is polyploid with genome copies ranging from approximately 200?900 per cell, making it a most suitable target for single cell finishing efforts. For single cell shotgun sequencing, an individual Sulcia cell was isolated and whole genome amplified by multiple displacement amplification (MDA). Sanger-based finishing methods allowed us to close the genome. To verify the correctness of our single cell genome and exclude MDA-derived artifacts, we independently shotgun sequenced and assembled the Sulcia genome from pooled bacteriomes using a metagenomic approach, yielding a nearly identical genome. Four variations we detected appear to be genuine biological differences between the two samples. Comparison of the single cell genome with bacteriome metagenomic sequence data detected two single nucleotide polymorphisms (SNPs), indicating extremely low genetic diversity within a Sulcia population. This study demonstrates the power of single cell genomics to generate a complete, high quality, non-composite reference genome within an environmental sample, which can be used for population genetic analyzes.

  5. Effect of heavy metals on bacterial transport

    Science.gov (United States)

    Zhang, H.; Olson, M. S.

    2010-12-01

    Adsorption of metals onto bacteria and soil takes place as stormwater runoff infiltrates into the subsurface. Changes in both bacterial surfaces and soil elemental content have been observed, and may alter the attachment of bacteria to soil surfaces. In this study, scanning electron microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS) analyses were performed on soil samples equilibrated with synthetic stormwater amended with copper, lead and zinc. The results demonstrate the presence of copper and zinc on soil surfaces. To investigate bacterial attachment behavior, sets of batch sorption experiments were conducted on Escherichia Coli (E. coli) under different chemical conditions by varying solution compositions (nutrient solution vs synthetic stormwater). The adsorption data is best described using theoretical linear isotherms. The equilibrium coefficient (Kd) of E. coli is higher in synthetic stormwater than in nutrient solution without heavy metals. The adsorption of heavy metals onto bacterial surfaces significantly decreases their negative surface charge as determined via zeta potential measurements (-17.0±5.96mv for E. coli equilibrated with synthetic stormwater vs -21.6±5.45mv for E. coli equilibrated with nutrient solution), indicating that bacterial attachment may increase due to the attachment of metals onto bacterial surfaces and their subsequent change in surface charge. The attachment efficiency (α) of bacteria was also calculated and compared for both solution chemistries. Bacterial attachment efficiency (α) in synthetic stormwater is 0.997, which is twice as high as that in nutrient solution(α 0.465). The ratio of bacterial diameter : collector diameter suggests minimal soil straining during bacterial transport. Results suggest that the presence of metals in synthetic stormwater leads to an increase in bacterial attachment to soil surfaces. In terms of designing stormwater infiltration basins, the presence of heavy metals seems to

  6. Bioreporter bacteria for landmine detection

    Energy Technology Data Exchange (ETDEWEB)

    Burlage, R.S. [Oak Ridge National Lab., TN (United States); Youngblood, T. [Frisby Technologies, Aiken, SC (United States); Lamothe, D. [American Technologies, Inc., Huntsville, AL (United States). Ordnance/Explosives Environmental Services Div.

    1998-04-01

    Landmines (and other UXO) gradually leak explosive chemicals into the soil at significant concentrations. Bacteria, which have adapted to scavenge low concentrations of nutrients, can detect these explosive chemicals. Uptake of these chemicals results in the triggering of specific bacterial genes. The authors have created genetically recombinant bioreporter bacteria that detect small concentrations of energetic chemicals. These bacteria are genetically engineered to produce a bioluminescent signal when they contact specific explosives. A gene for a brightly fluorescent compound can be substituted for increased sensitivity. By finding the fluorescent bacteria, you find the landmine. Detection might be accomplished using stand-off illumination of the minefield and GPS technology, which would result in greatly reduced risk to the deminers. Bioreporter technology has been proven at the laboratory scale, and will be tested under field conditions in the near future. They have created a bacterial strain that detects sub-micromolar concentrations of o- and p-nitrotoluene. Related bacterial strains were produced using standard laboratory protocols, and bioreporters of dinitrotoluene and trinitrotoluene were produced, screening for activity with the explosive compounds. Response time is dependent on the growth rate of the bacteria. Although frill signal production may require several hours, the bacteria can be applied over vast areas and scanned quickly, producing an equivalent detection speed that is very fast. This technology may be applicable to other needs, such as locating buried explosives at military and ordnance/explosive manufacturing facilities.

  7. Autoproteolytic Activation of Bacterial Toxins

    Directory of Open Access Journals (Sweden)

    Aimee Shen

    2010-05-01

    Full Text Available Protease domains within toxins typically act as the primary effector domain within target cells. By contrast, the primary function of the cysteine protease domain (CPD in Multifunctional Autoprocessing RTX-like (MARTX and Clostridium sp. glucosylating toxin families is to proteolytically cleave the toxin and release its cognate effector domains. The CPD becomes activated upon binding to the eukaryotic-specific small molecule, inositol hexakisphosphate (InsP6, which is found abundantly in the eukaryotic cytosol. This property allows the CPD to spatially and temporally regulate toxin activation, making it a prime candidate for developing anti-toxin therapeutics. In this review, we summarize recent findings related to defining the regulation of toxin function by the CPD and the development of inhibitors to prevent CPD-mediated activation of bacterial toxins.

  8. Bacterial ice crystal controlling proteins.

    Science.gov (United States)

    Lorv, Janet S H; Rose, David R; Glick, Bernard R

    2014-01-01

    Across the world, many ice active bacteria utilize ice crystal controlling proteins for aid in freezing tolerance at subzero temperatures. Ice crystal controlling proteins include both antifreeze and ice nucleation proteins. Antifreeze proteins minimize freezing damage by inhibiting growth of large ice crystals, while ice nucleation proteins induce formation of embryonic ice crystals. Although both protein classes have differing functions, these proteins use the same ice binding mechanisms. Rather than direct binding, it is probable that these protein classes create an ice surface prior to ice crystal surface adsorption. Function is differentiated by molecular size of the protein. This paper reviews the similar and different aspects of bacterial antifreeze and ice nucleation proteins, the role of these proteins in freezing tolerance, prevalence of these proteins in psychrophiles, and current mechanisms of protein-ice interactions. PMID:24579057

  9. Unexpected versatility in bacterial riboswitches.

    Science.gov (United States)

    Mellin, J R; Cossart, Pascale

    2015-03-01

    Bacterial riboswitches are elements present in the 5'-untranslated regions (UTRs) of mRNA molecules that bind to ligands and regulate the expression of downstream genes. Riboswitches typically regulate the expression of protein-coding genes. However, mechanisms of riboswitch-mediated regulation have recently been shown to be more diverse than originally thought, with reports showing that riboswitches can regulate the expression of noncoding RNAs and control the access of proteins, such as transcription termination factor Rho and RNase E, to a nascent RNA. Riboswitches are also increasingly used in biotechnology, with advances in the engineering of synthetic riboswitches and the development of riboswitch-based sensors. In this review we address the emerging roles and mechanisms of riboswitch-mediated regulation in natura and recent progress in the development of riboswitch-based technology. PMID:25708284

  10. Bacterial communities in batch and continuous-flow wetlands treating the herbicide S-metolachlor

    Energy Technology Data Exchange (ETDEWEB)

    Elsayed, O.F. [Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS (France); Génétique Moléculaire, Génomique, Microbiologie (GMGM), UMR 7156 University of Strasbourg/CNRS (France); Maillard, E. [Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS (France); Vuilleumier, S. [Génétique Moléculaire, Génomique, Microbiologie (GMGM), UMR 7156 University of Strasbourg/CNRS (France); Imfeld, G., E-mail: imfeld@unistra.fr [Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS (France)

    2014-11-15

    Knowledge of wetland bacterial communities in the context of pesticide contamination and hydrological regime is scarce. We investigated the bacterial composition in constructed wetlands receiving Mercantor Gold{sup ®} contaminated water (960 g L{sup −1} of the herbicide S-metolachlor, > 80% of the S-enantiomer) operated under continuous-flow or batch modes to evaluate the impact of the hydraulic regime. In the continuous-flow wetland, S-metolachlor mass removal was > 40%, whereas in the batch wetland, almost complete removal of S-metolachlor (93–97%) was observed. Detection of ethanesulfonic and oxanilic acid degradation products further indicated S-metolachlor biodegradation in the two wetlands. The dominant bacterial populations were characterised by terminal restriction fragment length polymorphism (T-RFLP) and 454 pyrosequencing. The bacterial profiles evolved during the first 35 days of the experiment, starting from a composition similar to that of inlet water, with the use of nitrate and to a lesser extent sulphate and manganese as terminal electron acceptors for microbial metabolism. Proteobacteria were the most abundant phylum, with Beta-, Alpha- and Gammaproteobacteria representing 26%, 19% and 17% respectively of total bacterial abundance. Bacterial composition in wetland water changed gradually over time in continuous-flow wetland and more abruptly in the batch wetland. Differences in overall bacterial water structure in the two systems were modest but significant (p = 0.008), and S-metolachlor, nitrate, and total inorganic carbon concentrations correlated with changes in the bacterial profiles. Together, the results highlight that bacterial composition profiles and their dynamics may be used as bioindicators of herbicide exposure and hydraulic disturbances in wetland systems. - Highlights: • We evaluated the bacterial composition in wetlands treating S-metolachlor • Hydraulic regime impacted biogeochemical processes and S-metolachlor removal

  11. Bacterial colonization of colonic crypt mucous gel and disease activity in ulcerative colitis.

    LENUS (Irish Health Repository)

    Rowan, Fiachra

    2012-02-01

    OBJECTIVE: To optimize total bacterial 16S rRNA quantification in microdissected colonic crypts in healthy controls and patients with ulcerative colitis (UC) and to characterize the findings with disease activity. BACKGROUND: Microscopic and molecular techniques have recently converged to allow bacterial enumeration in remote anatomic locations [eg, crypt-associated mucous gel (CAMG)]. The aims of this study were to combine laser capture microdissection (LCM) and 16S rRNA-based quantitative polymerase chain reaction (qPCR) to determine total bacterial copy number in CAMG both in health and in UC and to characterize the findings with disease activity. METHODS: LCM was used to microdissect CAMG from colonic mucosal biopsies from controls (n = 20) and patients with acute (n = 10) or subacute (n = 10) UC. Pan-bacterial 16S rRNA copy number per millimeter square in samples from 6 locations across the large bowel was obtained by qPCR using Desulfovibrio desulfuricans as a reference strain. Copy numbers were correlated with the UC disease activity index (UCDAI) and the simple clinical colitis activity index (SCCAI). RESULTS: Bacterial colonization of CAMG was detectable in all groups. Copy numbers were significantly reduced in acute UC. In subacute colitis, there was a positive correlation between copy number and UCDAI and SCCAI in the ascending, transverse and sigmoid colon. CONCLUSIONS: This study describes a sensitive method of quantitatively assessing bacterial colonization of the colonic CAMG. A positive correlation was found between CAMG bacterial load and subacute disease activity in UC, whereas detectable bacterial load was reduced in acute UC.

  12. Relationship between laser fluorescence and bacterial invasion in arrested dentinal carious lesions.

    Science.gov (United States)

    Iwami, Yukiteru; Yamamoto, Hiroko; Hayashi, Mikako; Ebisu, Shigeyuki

    2011-07-01

    This study investigated the relationship between caries assessment using a laser fluorescence device (DIAGNOdent), and bacterial invasion in arrested carious dentin detected by polymerase chain reaction (PCR). The ten extracted human molars used in this study had black or dark brown, hard occlusal carious lesions, and were found to be only weakly stained or unstained with a caries detector dye of 1% acid red in propylene glycol. In those extracted human molars, dentin was removed in the direction of the pulp chamber at 150-μm intervals. During each removal (104 sections in total), the dentin surface was assessed with DIAGNOdent, and a dentinal tissue sample was taken with a round bur. Bacterial DNA of each tissue sample was examined using PCR and primers based on the nucleotide sequence of a conserved region of bacterial 16S rDNA. Rates of bacterial detection increased as the DIAGNOdent values increased. When the DIAGNOdent values were DIAGNOdent values was 0.87. These results indicate that the DIAGNOdent values of arrested dentinal carious lesion were closely related to the rates of bacterial detection.

  13. Use of Bacteriophages to control bacterial pathogens

    Science.gov (United States)

    Lytic bacteriophages can provide a natural method and an effective alternative to antibiotics to reduce bacterial pathogens in animals, foods, and other environments. Bacteriophages (phages) are viruses which infect bacterial cells and eventually kill them through lysis, and represent the most abun...

  14. Plant Natural Products Targeting Bacterial Virulence Factors.

    Science.gov (United States)

    Silva, Laura Nunes; Zimmer, Karine Rigon; Macedo, Alexandre José; Trentin, Danielle Silva

    2016-08-24

    Decreased antimicrobial efficiency has become a global public health issue. The paucity of new antibacterial drugs is evident, and the arsenal against infectious diseases needs to be improved urgently. The selection of plants as a source of prototype compounds is appropriate, since plant species naturally produce a wide range of secondary metabolites that act as a chemical line of defense against microorganisms in the environment. Although traditional approaches to combat microbial infections remain effective, targeting microbial virulence rather than survival seems to be an exciting strategy, since the modulation of virulence factors might lead to a milder evolutionary pressure for the development of resistance. Additionally, anti-infective chemotherapies may be successfully achieved by combining antivirulence and conventional antimicrobials, extending the lifespan of these drugs. This review presents an updated discussion of natural compounds isolated from plants with chemically characterized structures and activity against the major bacterial virulence factors: quorum sensing, bacterial biofilms, bacterial motility, bacterial toxins, bacterial pigments, bacterial enzymes, and bacterial surfactants. Moreover, a critical analysis of the most promising virulence factors is presented, highlighting their potential as targets to attenuate bacterial virulence. The ongoing progress in the field of antivirulence therapy may therefore help to translate this promising concept into real intervention strategies in clinical areas. PMID:27437994

  15. Bacterial cell division proteins as antibiotic targets

    NARCIS (Netherlands)

    T. den Blaauwen; J.M. Andreu; O. Monasterio

    2014-01-01

    Proteins involved in bacterial cell division often do not have a counterpart in eukaryotic cells and they are essential for the survival of the bacteria. The genetic accessibility of many bacterial species in combination with the Green Fluorescence Protein revolution to study localization of protein

  16. Recent advances in bacterial heme protein biochemistry

    OpenAIRE

    Mayfield, Jeffery A.; Dehner, Carolyn A.; Dubois, Jennifer L.

    2011-01-01

    Recent progress in genetics, fed by the burst in genome sequence data, has led to the identification of a host of novel bacterial heme proteins that are now being characterized in structural and mechanistic terms. The following short review highlights very recent work with bacterial heme proteins involved in the uptake, biosynthesis, degradation, and use of heme in respiration and sensing.

  17. Multiple bacterial species reside in chronic wounds

    DEFF Research Database (Denmark)

    Gjødsbøl, Kristine; Christensen, Jens Jørgen; Karlsmark, Tonny;

    2006-01-01

    The aim of the study was to investigate the bacterial profile of chronic venous leg ulcers and the importance of the profile to ulcer development. Patients with persisting venous leg ulcers were included and followed for 8 weeks. Every second week, ulcer samples were collected and the bacterial s...

  18. Bacterial biofilms: prokaryotic adventures in multicellularity

    DEFF Research Database (Denmark)

    Webb, J.S.; Givskov, Michael Christian; Kjelleberg, S.

    2003-01-01

    The development of bacterial biofilms includes both the initial social behavior of undifferentiated cells, as well as cell death and differentiation in the mature biofilm, and displays several striking similarities with higher organisms. Recent advances in the field provide new insight...... into differentiation and cell death events in bacterial biofilm development and propose that biofilms have an unexpected level of multicellularity....

  19. Barriers to bacterial motility on unsaturated surfaces

    DEFF Research Database (Denmark)

    Dechesne, Arnaud; Smets, Barth F.

    2013-01-01

    and their isogenic mutants unable to express various type of motility we aimed to quantify the physical limits of bacterial motility. Our results demonstrate how hydration controls bacterial motility under unsaturated conditions. They can form the base of improved biodegradation models that include microbial...

  20. Sustainable strategies for treatment of bacterial infections

    DEFF Research Database (Denmark)

    Molin, Søren

    2014-01-01

    not in a foreseeable future develop novel approaches and strategies to combat bacterial infections, many people will be at risk of dying from even trivial infections for which we until recently had highly effective antibiotics. We have for a number of years investigated chronic bacterial lung infections in patients...