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Sample records for high-level gentamicin-resistant enterococci

  1. In vitro antibacterial activity of seven Indian spices against high level gentamicin resistant strains of enterococci

    PubMed Central

    Bipin, Chapagain; Chitra, Pai (Bhat); Minakshi, Bhattacharjee

    2015-01-01

    Introduction The aim of the study was to explore the in vitro antibacterial activity of seven ethanolic extracts of spices against high level gentamicin resistant (HLGR) enterococci isolated from human clinical samples. Material and methods Two hundred and fifteen enterococcal strains were isolated from clinical samples. High level gentamicin resistance in ethanolic extracts of cumin (Cuminum cyminum), cinnamon (Cinnamomum zeylanicum), ginger (Zingiber officinale), fenugreek (Trigonella foenum-graecum), cloves (Syzygium aromaticum), cardamom (Elettaria cardamomum Maton) and black pepper (Piper nigrum) were prepared using Soxhlet apparatus. The antibacterial effect of the extracts was studied using the well diffusion method. Statistical analysis was carried out by χ2 test using SPSS 17 software. Results Only cinnamon and ginger were found to have activity against all the isolates, whereas cumin and cloves had a variable effect on the strains. Fenugreek, black pepper and cardamom did not show any effect on the isolates. The zone diameter of inhibition obtained for cinnamon, ginger, cloves and cumin was in the range 31–34 mm, 27–30 mm, 25–26 mm and 19–20 mm respectively. Conclusions Cinnamomum zeylanicum and Z. officinale showed the maximum antibacterial activity against the enterococcal isolates followed by S. aromaticum and C. cyminum. The findings of the study show that spices used in the study can contribute to the development of potential antimicrobial agents for inclusion in the anti-enterococcal treatment regimen. PMID:26322099

  2. High-level gentamicin resistance and vancomycin resistance in clinical isolates of enterococci in a tertiary care hospital in eastern Nepal.

    PubMed

    Nepal, H P; Khanal, B; Acharya, A; Gyawali, N; Jha, P K; Paudel, R

    2012-03-01

    High-level gentamicin resistance and vancomycin resistance in enterococci, a family of important opportunistic pathogens, have emerged as a significant clinical problem over recent years. The present study was conducted to determine the high-level gentamicin and vancomycin resistance among the clinical isolates of enterococci. A total of 110 phenotypically identified enterococcal isolates were subjected to determination of high-level gentamicin resistance (by disk diffusion and agar dilution methods) and vancomycin resistance (by agar screening and agar dilution methods). About 36% of the isolates were found to have high-level gentamicin resistance, which indicates that gentamicin no longer remains an appropriate choice for inclusion in combination therapy with cell wall-active agents. Ten percent isolates exhibited resisance to vancomycin during screening. However, agar dilution confirmed that the isolates did not have resistance to vancomycin but had reduced susceptibility to it, which indicates their impending emergence of resistance to vancomycin.

  3. A New High-Level Gentamicin Resistance Gene, aph(2")-Id, in Enterococcus spp.

    PubMed Central

    Tsai, Shane F.; Zervos, Marcus J.; Clewell, Don B.; Donabedian, Susan M.; Sahm, Daniel F.; Chow, Joseph W.

    1998-01-01

    Enterococcus casseliflavus UC73 is a clinical blood isolate with high-level resistance to gentamicin. DNA preparations from UC73 failed to hybridize with intragenic probes for aac(6′)-Ie-aph(2")-Ia and aph(2")-Ic. A 4-kb fragment from UC73 was cloned and found to confer resistance to gentamicin in Escherichia coli DH5α transformants. Nucleotide sequence analysis revealed the presence of a 906-bp open reading frame whose deduced amino acid sequence had a region with homology to the aminoglycoside-modifying enzyme APH(2")-Ic and to the C-terminal domain of the bifunctional enzyme AAC(6′)-APH(2"). The gene is designated aph(2")-Id, and its observed phosphotransferase activity is designated APH(2")-Id. A PCR-generated intragenic probe hybridized to the genomic DNA from 17 of 118 enterococcal clinical isolates (108 with high-level gentamicin resistance) from five hospitals. All 17 were vancomycin-resistant Enterococcus faecium isolates, and pulsed-field typing revealed three distinct clones. The combination of ampicillin plus either amikacin or neomycin exhibited synergistic killing against E. casseliflavus UC73. Screening and interpretation of high-level aminoglycoside resistance in enterococci may need to be modified to include detection of APH(2")-Id. PMID:9593155

  4. Assessment of pheromone response in biofilm forming clinical isolates of high level gentamicin resistant Enterococcus faecalis.

    PubMed

    Jayanthi, S; Ananthasubramanian, M; Appalaraju, B

    2008-01-01

    Twenty five clinical isolates of high level gentamicin resistant Enterococcus faecalis were tested for their biofilm formation and pheromone responsiveness. The biofilm assay was carried out using microtiter plate method. Two isolates out of the 25 (8%) were high biofilm formers and 19 (76%) and four (16%) isolates were moderate and weak biofilm formers respectively. All the isolates responded to pheromones of E. faecalis FA2-2 strain. On addition of pheromone producing E. faecalis FA2-2 strain to these isolates, seven of 19 (37%) moderate biofilm formers developed into high biofilm formers. Similarly one of the 4 (25%) weak biofilm formers developed into high level biofilm former. Twelve (48%) of the 25 isolates were transconjugated by cross streak method using gentamicin as selective marker. This proves that the genetic factor for gentamicin resistance is present in the pheromone responsive plasmid. Among these twelve transaconjugants, seven isolates and one isolate were high biofilm formers on addition of E. faecalis FA2-2 and prior to its addition respectively. Out of the total 25 isolates, eight transconjugants for gentamicin resistance could turn to high biofilm formers on addition of the pheromone producing strain. All the isolates were resistant to more than two antibiotics tested. All the isolates were sensitive to vancomycin. The results indicate the significance of this nosocomial pathogen in biofilm formation and the role of pheromone responding clinical isolates of E. faecalis in spread of multidrug resistance genes.

  5. Evaluation of the Kirby-Bauer disc diffusion test as a screening test for high-level aminoglycoside resistance in enterococci.

    PubMed

    Pfaller, M A; Niles, A C; Murray, P R

    1984-10-01

    The Kirby-Bauer disc diffusion test was evaluated as a test to detect high-level aminoglycoside (streptomycin, kanamycin, tobramycin, and gentamicin) resistance in isolates of enterococci. The authors found that high-level resistance could not be predicted accurately with the diffusion test.

  6. Detection of the esp gene in high-level gentamicin resistant Enterococcus faecalis strains from pet animals in Japan.

    PubMed

    Harada, Tetsuya; Tsuji, Noboru; Otsuki, Koichi; Murase, Toshiyuki

    2005-03-20

    We investigated the prevalence of the esp gene and the susceptibility to gentamicin in Enterococcus faecalis and E. faecium strains obtained from pet animals. Nine of 30 E. faecalis and 2 of 38 E. faecium strains from the pet animals had the esp gene. Three esp-positive E. faecalis strains, which were isolated from two dogs and a cat, showed gentamicin MICs of > or =256 microg/ml and harbored the high-level gentamicin resistance (HLGR) gene, aac(6')-Ie-aph(2'')-Ia. Of the nine esp-positive E. faecalis strains, five, including the three strains with the HLGR gene, were closely related by numerical analysis of PFGE patterns. Longitudinal investigation needs to elucidate whether the HLGR gene was incorporated into a subpopulation of the esp-positive E. faecalis.

  7. Enterococci from Bangkok, Thailand, with high-level resistance to currently available aminoglycosides.

    PubMed Central

    Murray, B E; Tsao, J; Panida, J

    1983-01-01

    Enterococcal endocarditis is usually treated with a combination of a penicillin and an aminoglycoside. Recent reports have documented the emergence of enterococci in France with high-level resistance to gentamicin, tobramycin, and kanamycin and the emergence of strains in Houston, Tex. with high-level resistance to all of these drugs and streptomycin. In this study, we examined strains from a geographic area where newer aminoglycosides have been less commonly used. Of 125 distinct patient isolates, 18 (14%) were resistant to greater than 2,000 micrograms of gentamicin and most other aminoglycosides per ml. Four of these strains transferred gentamicin resistance to a laboratory recipient. One strain, chosen for further study, was resistant to synergism between penicillin and gentamicin, tobramycin, kanamycin, streptomycin, and amikacin and demonstrated the following enzymatic activities: 3'- and 2"-aminoglycoside phosphotransferases, 6'-aminoglycoside acetyltransferase, and adenylylation of streptomycin. Optimal therapy for endocarditis caused by such highly resistant strains is currently unknown. PMID:6614889

  8. High-level aminoglycoside resistant enterococci isolated from swine.

    PubMed Central

    Jackson, C. R.; Fedorka-Cray, P. J.; Barrett, J. B.; Ladely, S. R.

    2005-01-01

    Approximately 42% (187/444) of swine enterococci collected between the years 1999 and 2000 exhibited high-level resistance to gentamicin (MIC > or =500 microg/ml), kanamycin (MIC > or =500 microg/ml), or streptomycin (MIC > or =1000 microg/ml). Eight aminoglycoside resistance genes were detected using PCR, most frequently ant(6)-Ia and aac(6')-Ii from Enterococcus faecium. Twenty-four per cent (45/187) of total high-level aminoglycoside-resistant isolates and 26% (4/15) of isolates resistant to high levels of all three antimicrobials were negative for all genes tested. These data suggest that enterococci isolated from swine contain diverse and possibly unidentified aminoglycoside resistance genes. PMID:15816164

  9. High-level aminoglycoside resistant enterococci isolated from swine.

    PubMed

    Jackson, C R; Fedorka-Cray, P J; Barrett, J B; Ladely, S R

    2005-04-01

    Approximately 42% (187/444) of swine enterococci collected between the years 1999 and 2000 exhibited high-level resistance to gentamicin (MIC > or =500 microg/ml), kanamycin (MIC > or =500 microg/ml), or streptomycin (MIC > or =1000 microg/ml). Eight aminoglycoside resistance genes were detected using PCR, most frequently ant(6)-Ia and aac(6')-Ii from Enterococcus faecium. Twenty-four per cent (45/187) of total high-level aminoglycoside-resistant isolates and 26% (4/15) of isolates resistant to high levels of all three antimicrobials were negative for all genes tested. These data suggest that enterococci isolated from swine contain diverse and possibly unidentified aminoglycoside resistance genes.

  10. OCCURRENCE OF HIGH-LEVEL AMINOGLYCOSIDE RESISTANCE IN ENVIRONMENTAL ISOLATES OF ENTEROCOCCI

    EPA Science Inventory

    High-level resistance fo aminoglycosides was observed in environmental isolates of enterococci. Various aquatic habitats, including agricultural runoff, creeks, rivers, wastewater, and wells, were analyzed. Strains of Enterococcus faecalis, e.faecium, E. gallinarum, and other Ent...

  11. High-level aminoglycoside resistance and virulence characteristics among Enterococci isolated from recreational beaches in Malaysia.

    PubMed

    Dada, Ayokunle Christopher; Ahmad, Asmat; Usup, Gires; Heng, Lee Yook; Hamid, Rahimi

    2013-09-01

    We report the first study on the occurrence of high-level aminoglycoside-resistant (HLAR) Enterococci in coastal bathing waters and beach sand in Malaysia. None of the encountered isolates were resistant to high levels of gentamicin (500 μg/mL). However, high-level resistance to kanamycin (2,000 μg/mL) was observed in 14.2 % of tested isolates, the highest proportions observed being among beach sand isolates. High-level resistance to kanamycin was higher among Enterococcus faecalis and Enterococcus faecium than Enterococcus spp. Chi-square analysis showed no significant association between responses to tested antibiotics and the species allocation or source of isolation of all tested Enterococci. The species classification of encountered Enterococci resistance to vancomycin was highest among Enterococcus spp. (5.89 %) followed by E. faecium (4.785) and least among E. faecalis. A total of 160 isolates were also tested for virulence characteristics. On the whole, caseinase production was profoundly highest (15.01 %) while the least prevalent virulence characteristic observed among tested beach Enterococci was haemolysis of rabbit blood (3.65 %). A strong association was observed between the source of isolation and responses for each of caseinase (C = 0.47, V = 0.53) and slime (C = 0.50, V = 0.58) assays. Analysis of obtained spearman's coefficient showed a strong correlation between caseinase and each of the slime production (p = 0.04), gelatinase (p = 0.0035) and haemolytic activity on horse blood (p = 0.004), respectively. Suggestively, these are the main virulent characteristics of the studied beach Enterococci. Our findings suggest that recreational beaches may contribute to the dissemination of Enterococci with HLAR and virulence characteristics.

  12. Investigation of the reformulated Remel Synergy Quad plate for detection of high-level aminoglycoside and vancomycin resistance among enterococci.

    PubMed

    Free, L; Sahm, D F

    1995-06-01

    We investigated the accuracy of the recently released Remel Synergy Quad plate, a commercially available agar screening method for detecting high-level aminoglycoside and vancomycin resistance among enterococci that is based on the National Committee for Clinical Laboratory Standards recommended guidelines (National Committee for Clinical Laboratory Standards, M7-A3, 1993). The Synergy Quad correctly determined the gentamicin and streptomycin resistance status for > or = 97% of 147 Enterococcus faecalis and Enterococcus faecium isolates tested. Detection of vancomycin resistance also was reliable, as no false susceptibility occurred with 36 vancomycin-resistant E. faecalis and E. faecium strains and false resistance occurred only once with the 47 susceptible strains tested. One strain each of Enterococcus gallinarum and Enterococcus casseliflavus failed to grow on the screen, but because the true nature and significance of resistance in such isolates is unknown the implication of their screen negativity is uncertain. In summary, the Remel Synergy Quad provides a highly accurate and convenient method for susceptibility testing of enterococci against gentamicin, streptomycin, and vancomycin.

  13. Gentamicin resistance among Escherichia coli strains isolated in neonatal sepsis.

    PubMed

    Hasvold, J; Bradford, L; Nelson, C; Harrison, C; Attar, M; Stillwell, T

    2013-01-01

    Neonatal sepsis is a significant cause of morbidity and mortality among term and preterm infants. Ampicillin and gentamicin are standard empiric therapy for early onset sepsis. Four cases of neonatal sepsis secondary to Escherichia coli (E. coli) found to be gentamicin resistant occurred within a five week period in one neonatal intensive care unit (NICU). To determine whether these cases could be tied to a single vector of transmission, and to more broadly evaluate the incidence of gentamicin resistant strains of E. coli in the neonatal population at our institution compared to other centers, we reviewed the charts of the four neonates (Infants A through D) and their mothers. The E. coli isolates were sent for Pulse Field Gel Electrophoresis (PFGE) to evaluate for genetic similarity between strains. We also reviewed all positive E. coli cultures from one NICU over a two year period. Infants A and B had genetically indistinguishable strains which matched that of urine and placental cultures of Infant B's mother. Infant C had a genetically distinct organism. Infant D, the identical twin of Infant C, did not have typing performed. Review of all cultures positive for E. coli at our institution showed a 12.9 percent incidence of gentamicin-resistance. A review of other studies showed that rates of resistance vary considerably by institution. We conclude that gentamicin-resistant E. coli is a relatively uncommon cause of neonatal sepsis, but should remain a consideration in patients who deteriorate despite initiation of empiric antibiotics.

  14. Identification and control of a gentamicin resistant, meticillin susceptible Staphylococcus aureus outbreak on a neonatal unit

    PubMed Central

    Davies, Bethany; Menson, Esse; Klein, John L; Watts, Timothy L; Kearns, Angela M; Pichon, Bruno; Edgeworth, Jonathan D; French, Gary L

    2014-01-01

    We describe the identification and control of an outbreak of gentamicin resistant, meticillin susceptible Staphylococcus aureus (GR-MSSA) on a 36-bed neonatal unit (NNU) in London. Control measures included admission and weekly screening for GR-MSSA, cohorting affected babies, environmental and staff screening, hydrogen peroxide vapour (HPV) for terminal disinfection of cohort rooms, and reinforcement of hand hygiene. Seventeen babies were affected by the outbreak strain over ten months; seven were infected and ten were asymptomatic carriers. The outbreak strain was gentamicin resistant and all isolates were indistinguishable by pulsed-field gel electrophoresis. The outbreak strains spread rapidly and were associated with a high rate of bacteraemia (35% of 17 affected patients had bacteraemia vs. 10% of 284 patients with MSSA prior to the outbreak, p=0.007). None of 113 staff members tested were colonised with GR-MSSA. GR-MSSA was recovered from 11.5% of 87 environmental surfaces in cohort rooms, 7.1% of 28 communal surfaces and 4.1% of 74 surfaces after conventional terminal disinfection. None of 64 surfaces sampled after HPV decontamination yielded GR-MSSA. Recovery of GR-MSSA from two high level sites suggested that the organism could have been transmitted via air. Occasional breakdown in hand hygiene compliance and contaminated environmental surfaces probably contributed to transmission.

  15. Evaluation of a New System, VITEK 2, for Identification and Antimicrobial Susceptibility Testing of Enterococci

    PubMed Central

    Garcia-Garrote, Fernando; Cercenado, Emilia; Bouza, Emilio

    2000-01-01

    We evaluated the new automated VITEK 2 system (bioMérieux) for the identification and antimicrobial susceptibility testing of enterococci. The results obtained with the VITEK 2 system were compared to those obtained by reference methods: standard identification by the scheme of Facklam and Sahm [R. R. Facklam and D. F. Sahm, p. 308–314, in P. R. Murray et al., ed., Manual of Clinical Microbiology, 6th ed., 1995] and with the API 20 STREP system and, for antimicrobial susceptibility testing, broth microdilution and agar dilution methods by the procedures of the National Committee for Clinical Laboratory Standards. The presence of vanA and vanB genes was determined by PCR. A total of 150 clinical isolates were studied, corresponding to 60 Enterococcus faecalis, 55 Enterococcus faecium, 26 Enterococcus gallinarum, 5 Enterococcus avium, 2 Enterococcus durans, and 2 Enterococcus raffinosus isolates. Among those isolates, 131 (87%) were correctly identified to the species level with the VITEK 2 system. Approximately half of the misidentifications were for E. faecium with low-level resistance to vancomycin, identified as E. gallinarum or E. casseliflavus; however, a motility test solved the discrepancies and increased the agreement to 94%. Among the strains studied, 66% were vancomycin resistant (57 VanA, 16 VanB, and 26 VanC strains), 23% were ampicillin resistant (MICs, ≥16 μg/ml), 31% were high-level gentamicin resistant, and 45% were high-level streptomycin resistant. Percentages of agreement for susceptibility and resistance to ampicillin, vancomycin, and teicoplanin and for high-level gentamicin resistance and high-level streptomycin resistance were 93, 95, 97, 97, and 96%, respectively. The accuracy of identification and antimicrobial susceptibility testing of enterococci with the VITEK 2 system, together with the significant reduction in handling time, will have a positive impact on the work flow of the clinical microbiology laboratory. PMID:10834961

  16. Evaluation of a new system, VITEK 2, for identification and antimicrobial susceptibility testing of enterococci.

    PubMed

    Garcia-Garrote, F; Cercenado, E; Bouza, E

    2000-06-01

    We evaluated the new automated VITEK 2 system (bioMérieux) for the identification and antimicrobial susceptibility testing of enterococci. The results obtained with the VITEK 2 system were compared to those obtained by reference methods: standard identification by the scheme of Facklam and Sahm [R. R. Facklam and D. F. Sahm, p. 308-314, in P. R. Murray et al., ed., Manual of Clinical Microbiology, 6th ed., 1995] and with the API 20 STREP system and, for antimicrobial susceptibility testing, broth microdilution and agar dilution methods by the procedures of the National Committee for Clinical Laboratory Standards. The presence of vanA and vanB genes was determined by PCR. A total of 150 clinical isolates were studied, corresponding to 60 Enterococcus faecalis, 55 Enterococcus faecium, 26 Enterococcus gallinarum, 5 Enterococcus avium, 2 Enterococcus durans, and 2 Enterococcus raffinosus isolates. Among those isolates, 131 (87%) were correctly identified to the species level with the VITEK 2 system. Approximately half of the misidentifications were for E. faecium with low-level resistance to vancomycin, identified as E. gallinarum or E. casseliflavus; however, a motility test solved the discrepancies and increased the agreement to 94%. Among the strains studied, 66% were vancomycin resistant (57 VanA, 16 VanB, and 26 VanC strains), 23% were ampicillin resistant (MICs, >/=16 microgram/ml), 31% were high-level gentamicin resistant, and 45% were high-level streptomycin resistant. Percentages of agreement for susceptibility and resistance to ampicillin, vancomycin, and teicoplanin and for high-level gentamicin resistance and high-level streptomycin resistance were 93, 95, 97, 97, and 96%, respectively. The accuracy of identification and antimicrobial susceptibility testing of enterococci with the VITEK 2 system, together with the significant reduction in handling time, will have a positive impact on the work flow of the clinical microbiology laboratory.

  17. Antibiotic resistance and mechanisms implicated in clinical enterococci in a Tunisian hospital.

    PubMed

    Klibi, N; Gharbi, S; Masmoudi, A; Ben Slama, K; Poeta, P; Zarazaga, M; Fendri, C; Boudabous, A; Torres, C

    2006-02-01

    Susceptibility testing for 15 antibiotics was performed in a series of 191 clinical enterococci recovered in a Tunisian Hospital during 2000-2003. Species detected were the following ones (number of isolates): E. faecalis (139), E. faecium (41), E. casseliflavus (5), E. gallinarum (3), E. avium (2) and E. hirae (1). The percentages of antibiotic resistance detected were as follows (E. faecalis/ E. faecium/ other species) : penicillin (0/ 73/ 9%), tetracycline (78/ 44/ 54%), chloramphenicol (52/ 29/ 27%), erythromycin (66/ 100/ 82%), spiramycin (84/ 83/ 64%), pristinamycin (100/ 0/ 73%), trimethoprim-sulfamethoxazole (88/ 78/ 91%), rifampicin (72/ 41/ 0%), vancomycin (0/ 0/ 36%), teicoplanin (0/ 0/ 0%), high-level-resistance for gentamicin (24/ 29/ 45%), streptomycin (34/ 56/ 55%) and kanamycin (41/ 68/ 55%). Increased vancomycin minimum inhibitory concentrations (MICs) were only detected in E. casseliflavus and E. gallinarum isolates (MIC range 8-24 microg/ml). The erm(B), catA, tet(M), aac(6')-aph(2''), aph(3')-IIIa, and ant(6)-Ia genes were detected in 91%, 32%, 86%, 98%, 100%, and 72% of the E. faecium and E. faecalis isolates resistant to erythromycin, chloramphenicol, tetracycline and high-level-resistant to gentamicin, kanamycin and streptomycin, respectively. A total of 20 unrelated pulsed-field-gel-electrophoresis patterns were found in the series of 46 high-level gentamicin-resistant E. faecalis and E. faecium isolates of this study.

  18. Prevalence of Virulence Factors and Drug Resistance in Clinical Isolates of Enterococci: A Study from North India

    PubMed Central

    Banerjee, Tuhina; Anupurba, Shampa

    2015-01-01

    Along with emergence of multidrug resistance, presence of several virulence factors in enterococci is an emerging concept. This study was undertaken to determine the prevalence of various virulence factors phenotypically and genotypically in enterococci and study their association with multidrug resistance. A total of 310 enterococcal isolates were studied, comprising 155 E. faecium and 155 E. faecalis. Antimicrobial susceptibility testing was done by disc diffusion and agar dilution method. Hemolysin, gelatinase, biofilm production, and haemagglutination were detected phenotypically and presence of virulence genes, namely, asa1, gelE, cylA, esp, and hyl, was detected by multiplex PCR. Of the total, 47.41% isolates were high level gentamicin resistant (HLGRE) and 7.09% were vancomycin resistant (VRE). All the virulence traits studied were found in varying proportions, with majority in E. faecalis (p > 0.05). Strong biofilm producers possessed either asa1 or gelE gene. gelE silent gene was detected in 41.37% (12/29). However, increase in resistance was associated with significant decrease in expression or acquisition of virulence genes. Further, acquisition of vancomycin resistance was the significant factor responsible for the loss of virulence traits. Though it is presumed that increased drug resistance correlates with increased virulence, acquisition of vancomycin resistance might be responsible for reduced expression of virulence traits to meet the “biological cost” relating to VRE. PMID:26366302

  19. Epidemiology of gentamicin-resistant, gram-negative bacillary colonization in a spinal cord injury unit.

    PubMed Central

    Shlaes, D M; Currie, C A; Rotter, G; Eanes, M; Floyd, R

    1983-01-01

    A prospective epidemiological survey of a spinal cord injury unit for gentamicin-resistant, gram-negative bacilli was undertaken. The initial survey of the unit suggested a low level of cross-infection involving Pseudomonas aeruginosa and Providencia stuartii. However, a longitudinal study of new admissions revealed that only 13 of 52 nosocomial acquisitions could be considered to be due to cross colonization. Comparison of data on antibiotic use did not suggest selective pressure for resistant endogenous flora. Nosocomial acquisition was directly related to the length of the hospital stay. Antibiotic susceptibility testing of gentamicin-resistant, gram-negative bacilli showed only minor differences between nosocomial isolates and those present during the initial survey. Of the usual antimicrobial agents, amikacin, carbenicillin, and cefoxitin were the most active against all organisms, with the exception of Serratia spp. Of the new beta-lactams, ceftazidime and imipemide (N-formimidoyl thienamycin) were most active. PMID:6619279

  20. Novel Pathways for Ameliorating the Fitness Cost of Gentamicin Resistant Small Colony Variants

    PubMed Central

    Vestergaard, Martin; Paulander, Wilhelm; Leng, Bingfeng; Nielsen, Jesper B.; Westh, Henrik T.; Ingmer, Hanne

    2016-01-01

    Small colony variants (SCVs) of the human pathogen Staphylococcus aureus are associated with persistent infections. Phenotypically, SCVs are characterized by slow growth and they can arise upon interruption of the electron transport chain that consequently reduce membrane potential and thereby limit uptake of aminoglycosides (e.g., gentamicin). In this study, we have examined the pathways by which the fitness cost of SCVs can be ameliorated. Five gentamicin resistant SCVs derived from S. aureus JE2 were independently selected on agar plates supplemented with gentamicin. The SCVs carried mutations in the menaquinone and hemin biosynthesis pathways, which caused a significant reduction in exponential growth rates relative to wild type (WT; 0.59–0.72) and reduced membrane potentials. Fifty independent lineages of the low-fitness, resistant mutants were serially passaged for up to 500 generations with or without sub-lethal concentrations of gentamicin. Amelioration of the fitness cost followed three evolutionary trajectories and was dependent on the initial mutation type (point mutation vs. deletion) and the passage condition (absence or presence of gentamicin). For SCVs evolved in the absence of gentamicin, 12 out of 15 lineages derived from SCVs with point mutations acquired intra-codonic suppressor mutations restoring membrane potential, growth rate, gentamicin susceptibility and colony size to WT levels. For the SCVs carrying deletions, all lineages enhanced fitness independent of membrane potential restoration without alterations in gentamicin resistance levels. By whole genome sequencing, we identified compensatory mutations in genes related to the σB stress response (7 out of 10 lineages). Inactivation of rpoF that encode for the alternative sigma factor SigB (σB) partially restored fitness of SCVs. For all lineages passaged in the presence of gentamicin, fitness compensation via membrane potential restoration was suppressed, however, selected for secondary

  1. Frequency of Resistance to Kanamycin, Tobramycin, Netilmicin, and Amikacin in Gentamicin-Resistant Gram-Negative Bacteria

    PubMed Central

    Seligman, Stephen J.

    1978-01-01

    In vitro evaluation of 66 epidemiologically distinct, gentamicin-resistant, gram-negative isolates from four hospitals revealed that 92% were kanamycin resistant, 44% were netilmicin resistant, 41% were tobramycin resistant, and 6% were amikacin resistant. Combined resistance to gentamicin, tobramycin, and netilmicin occurred in 30% of the strains. Although the resistance percentage to amikacin was the lowest of the three newer agents, two strains were resistant to all of the aminoglycosides tested. PMID:626492

  2. Wild birds as biological indicators of environmental pollution: antimicrobial resistance patterns of Escherichia coli and enterococci isolated from common buzzards (Buteo buteo).

    PubMed

    Radhouani, Hajer; Poeta, Patrícia; Gonçalves, Alexandre; Pacheco, Rui; Sargo, Roberto; Igrejas, Gilberto

    2012-06-01

    A total of 36 Escherichia coli and 31 enterococci isolates were recovered from 42 common buzzard faecal samples. The E. coli isolates showed high levels of resistance to streptomycin and tetracycline. The following resistance genes were detected: bla(TEM) (20 of 22 ampicillin-resistant isolates), tet(A) and/or tet(B) (16 of 27 tetracycline-resistant isolates), aadA1 (eight of 27 streptomycin-resistant isolates), cmlA (three of 15 chloramphenicol-resistant isolates), aac(3)-II with/without aac(3)-IV (all seven gentamicin-resistant isolates) and sul1 and/or sul2 and/or sul3 [all eight sulfamethoxazole/trimethoprim-resistant (SXT) isolates]. intI1 and intI2 genes were detected in four SXT-resistant isolates. The virulence-associated genes fimA (type 1 fimbriae), papC (P fimbriae) and aer (aerobactin) were detected in 61.1, 13.8 and 11.1% of the isolates, respectively. The isolates belonged to phylogroups A (47.2%), B1 (8.3%), B2 (13.9%) and D (30.5%). For the enterococci isolates, Enterococcus faecium was the most prevalent species (48.4%). High levels of tetracycline and erythromycin resistance were found among our isolates (87 and 81%, respectively). Most of the tetracycline-resistant strains carried the tet(M) and/or tet(L) genes. The erm(B) gene was detected in 80% of erythromycin-resistant isolates. The vat(D) and/or vat(E) genes were found in nine of the 17 quinupristin-dalfopristin-resistant isolates. The enterococcal isolates showing high-level resistance for kanamycin, gentamicin and streptomycin contained the aph(3')-IIIa, aac(6')-aph(2″) and ant(6)-Ia genes, respectively. This report reveals that common buzzards seem to represent an important reservoir, or at least a source, of multi-resistant E. coli and enterococci isolates, and consequently may represent a considerable hazard to human and animal health by transmission of these isolates to waterways and other environmental sources via their faecal deposits.

  3. A Cassette Containing Thiostrepton, Gentamicin Resistance Genes, and dif sequences Is Effective in Construction of Recombinant Mycobacteria

    PubMed Central

    Mugweru, Julius; Makafe, Gaelle; Cao, Yuanyuan; Zhang, Yang; Wang, Bangxing; Huang, Shaobo; Njire, Moses; Chhotaray, Chiranjibi; Tan, Yaoju; Li, Xinjie; Liu, Jianxiong; Tan, Shouyong; Deng, Jiaoyu; Zhang, Tianyu

    2017-01-01

    The genetic manipulation of Mycobacterium tuberculosis genome is limited by the availability of selection markers. Spontaneous resistance mutation rate of M. tuberculosis to the widely used kanamycin is relatively high which often leads to some false positive transformants. Due to the few available markers, we have created a cassette containing thiostrepton resistance gene (tsr) for selection in M. tuberculosis and M. bovis BCG, and gentamicin resistance gene (aacC1) for Escherichia coli and M. smegmatis mc2155, flanked with dif sequences recognized by the Xer system of mycobacteria. This cassette adds to the limited available selection markers for mycobacteria. PMID:28392781

  4. Enterococci in the Environment

    PubMed Central

    Byappanahalli, Muruleedhara N.; Nevers, Meredith B.; Korajkic, Asja; Staley, Zachery R.

    2012-01-01

    Summary: Enterococci are common, commensal members of gut communities in mammals and birds, yet they are also opportunistic pathogens that cause millions of human and animal infections annually. Because they are shed in human and animal feces, are readily culturable, and predict human health risks from exposure to polluted recreational waters, they are used as surrogates for waterborne pathogens and as fecal indicator bacteria (FIB) in research and in water quality testing throughout the world. Evidence from several decades of research demonstrates, however, that enterococci may be present in high densities in the absence of obvious fecal sources and that environmental reservoirs of these FIB are important sources and sinks, with the potential to impact water quality. This review focuses on the distribution and microbial ecology of enterococci in environmental (secondary) habitats, including the effect of environmental stressors; an outline of their known and apparent sources, sinks, and fluxes; and an overview of the use of enterococci as FIB. Finally, the significance of emerging methodologies, such as microbial source tracking (MST) and empirical predictive models, as tools in water quality monitoring is addressed. The mounting evidence for widespread extraenteric sources and reservoirs of enterococci demonstrates the versatility of the genus Enterococcus and argues for the necessity of a better understanding of their ecology in natural environments, as well as their roles as opportunistic pathogens and indicators of human pathogens. PMID:23204362

  5. Enterococci in the environment

    USGS Publications Warehouse

    Byappanahalli, Muruleedhara N.; Nevers, Meredith B.; Korajkic, Asja; Staley, Zachery R.; Harwood, Valerie J.

    2012-01-01

    Enterococci are common, commensal members of gut communities in mammals and birds, yet they are also opportunistic pathogens that cause millions of human and animal infections annually. Because they are shed in human and animal feces, are readily culturable, and predict human health risks from exposure to polluted recreational waters, they are used as surrogates for waterborne pathogens and as fecal indicator bacteria (FIB) in research and in water quality testing throughout the world. Evidence from several decades of research demonstrates, however, that enterococci may be present in high densities in the absence of obvious fecal sources and that environmental reservoirs of these FIB are important sources and sinks, with the potential to impact water quality. This review focuses on the distribution and microbial ecology of enterococci in environmental (secondary) habitats, including the effect of environmental stressors; an outline of their known and apparent sources, sinks, and fluxes; and an overview of the use of enterococci as FIB. Finally, the significance of emerging methodologies, such as microbial source tracking (MST) and empirical predictive models, as tools in water quality monitoring is addressed. The mounting evidence for widespread extraenteric sources and reservoirs of enterococci demonstrates the versatility of the genus Enterococcus and argues for the necessity of a better understanding of their ecology in natural environments, as well as their roles as opportunistic pathogens and indicators of human pathogens.

  6. Enterococci in the environment.

    PubMed

    Byappanahalli, Muruleedhara N; Nevers, Meredith B; Korajkic, Asja; Staley, Zachery R; Harwood, Valerie J

    2012-12-01

    Enterococci are common, commensal members of gut communities in mammals and birds, yet they are also opportunistic pathogens that cause millions of human and animal infections annually. Because they are shed in human and animal feces, are readily culturable, and predict human health risks from exposure to polluted recreational waters, they are used as surrogates for waterborne pathogens and as fecal indicator bacteria (FIB) in research and in water quality testing throughout the world. Evidence from several decades of research demonstrates, however, that enterococci may be present in high densities in the absence of obvious fecal sources and that environmental reservoirs of these FIB are important sources and sinks, with the potential to impact water quality. This review focuses on the distribution and microbial ecology of enterococci in environmental (secondary) habitats, including the effect of environmental stressors; an outline of their known and apparent sources, sinks, and fluxes; and an overview of the use of enterococci as FIB. Finally, the significance of emerging methodologies, such as microbial source tracking (MST) and empirical predictive models, as tools in water quality monitoring is addressed. The mounting evidence for widespread extraenteric sources and reservoirs of enterococci demonstrates the versatility of the genus Enterococcus and argues for the necessity of a better understanding of their ecology in natural environments, as well as their roles as opportunistic pathogens and indicators of human pathogens.

  7. Genome Shuffling and Gentamicin-Resistance to Improve ε-Poly-L-Lysine Productivity of Streptomyces albulus W-156.

    PubMed

    Wang, Liang; Chen, Xusheng; Wu, Guangyao; Zeng, Xin; Ren, Xidong; Li, Shu; Tang, Lei; Mao, Zhonggui

    2016-12-01

    Genome shuffling has been a recently effective method for screening the desirable phenotypes of industrial strains. Here, we combined genome shuffling and gentamicin resistance to improve the production of ε-poly-L-lysine in Streptomyces albulus W-156. Five starting mutants with higher ε-poly-L-lysine (ε-PL) productivities were firstly obtained by atmospheric and room temperature plasma (ARTP) mutagenesis. After three rounds of genome shuffling with increasing concentration of gentamicin for selection, S. albulus AG3-28, was finally got with a production of 3.43 g/L in shaking flask. In a 5-L fermenter, AG3-28 exhibited a higher ε-PL productivity (56.5 g/L) than the initial strain W-156 (37.5 g/L). Key enzyme activities in primary and secondary metabolic pathways were analyzed, and the transcription levels of hrdD and pls were determined by quantitative real time-polymerase chain reaction (qRT-PCR). Increase of key enzyme activities and the upregulation of the gene transcriptional levels demonstrated that ε-PL synthetic pathway in AG3-28 was obviously strengthened, which might be responsible for the high productivity. Moreover, hyper-yield strain AG3-28 was found to produce a slightly lower ε-PL polymerization degree than the parent strain. Amplified fragment length polymorphism (AFLP) analysis reflects the genetic diversity among the derivates after genome shuffling.

  8. Enterococci in the Environment

    EPA Science Inventory

    Enterococci are common, commensal members of gut communities in mammals and birds, yet they are also opportunistic pathogens that cause millions of human and animal infections annually. Because they are shed in human and animal feces, are readily culturable, and predict human hea...

  9. Virulence of enterococci.

    PubMed Central

    Jett, B D; Huycke, M M; Gilmore, M S

    1994-01-01

    Enterococci are commensal organisms well suited to survival in intestinal and vaginal tracts and the oral cavity. However, as for most bacteria described as causing human disease, enterococci also possess properties that can be ascribed roles in pathogenesis. The natural ability of enterococci to readily acquire, accumulate, and share extrachromosomal elements encoding virulence traits or antibiotic resistance genes lends advantages to their survival under unusual environmental stresses and in part explains their increasing importance as nosocomial pathogens. This review discusses the current understanding of enterococcal virulence relating to (i) adherence to host tissues, (ii) invasion and abscess formation, (iii) factors potentially relevant to modulation of host inflammatory responses, and (iv) potentially toxic secreted products. Aggregation substance, surface carbohydrates, or fibronectin-binding moieties may facilitate adherence to host tissues. Enterococcus faecalis appears to have the capacity to translocate across intact intestinal mucosa in models of antibiotic-induced superinfection. Extracellular toxins such as cytolysin can induce tissue damage as shown in an endophthalmitis model, increase mortality in combination with aggregation substance in an endocarditis model, and cause systemic toxicity in a murine peritonitis model. Finally, lipoteichoic acid, superoxide production, or pheromones and corresponding peptide inhibitors each may modulate local inflammatory reactions. Images PMID:7834601

  10. [Vancomycin and high-level aminoglycoside resistant Enterococcus carriage and the risk factors related to resistance in hospitalized patients].

    PubMed

    Yildirim, Mustafa; Sencan, Irfan; Ozdemir, Davut; Oksüz, Sükrü; Yilmaz, Zeynep; Sahin, Idris

    2007-04-01

    The aims of this study were to detect the prevalence of fecal vancomycin resistant Enterococcus (VRE) colonization with high-level resistance to aminoglycoside and other antibiotics and, the risk factors related to resistance in hospitalized patients in Düzce Medical Faculty Hospital, Turkey. A total of 105 patients (61 from internal medicine, 44 from surgery clinics; 54.3% female, mean age: 47.2 +/- 24.54 years) were included to the study and a single stool sample was collected from each of the patients. Specimens were cultivated in Enterococcus selective media (BioMerieux, France), and the isolates were identified by conventional microbiological methods together with the API 20 Strep test. Beta-lactamase activities of the isolates were tested with nitrocefin disk, and antibiotic susceptibilities were determined by the disk diffusion method. Enterococcus spp. were isolated from 81 (77%) of the patients' samples and 60.5% were identified as E. faecium, 13.6% as E. faecalis, 11.1% as E. gallinarum, 7.4% as E. durans, 2.5% as E. raffinosus, 2.5% as E. mundtii, 1.2% as E. casseliflavus, and 1.2% as E. avium. High-level streptomycin and gentamicin resistance rates were found in 19.8% and 9.9% of the isolates, respectively. The resistance rates for the other antibiotics were found as follows; 18.5% to ampicillin, 27.2% to penicilin, 34.6% to nitrofurantoin, 65.4% to norfloxacin, and 70.4% to both tetracycline and ciprofloxacin. No vancomycin resistance was detected, and none of the enterococci had beta-lactamase activity. Long hospitalization period, antibiotic usage and experience of intra-abdominal operation were found as the significant risk factors for colonization of the resistant bacteria. Our results demonstrated that there was no fecal VRE carriage in our hospital during the study period, however, it was concluded that the screening tests should be done periodically in order to detect resistant strains as soon as possible.

  11. Vancomycin-Resistant Enterococci

    PubMed Central

    Cetinkaya, Yesim; Falk, Pamela; Mayhall, C. Glen

    2000-01-01

    After they were first identified in the mid-1980s, vancomycin-resistant enterococci (VRE) spread rapidly and became a major problem in many institutions both in Europe and the United States. Since VRE have intrinsic resistance to most of the commonly used antibiotics and the ability to acquire resistance to most of the current available antibiotics, either by mutation or by receipt of foreign genetic material, they have a selective advantage over other microorganisms in the intestinal flora and pose a major therapeutic challenge. The possibility of transfer of vancomycin resistance genes to other gram-positive organisms raises significant concerns about the emergence of vancomycin-resistant Staphylococcus aureus. We review VRE, including their history, mechanisms of resistance, epidemiology, control measures, and treatment. PMID:11023964

  12. Complete Genome Sequences of Multidrug-Resistant Campylobacter jejuni Strain 14980A (Turkey Feces) and Campylobacter coli Strain 14983A (Housefly from a Turkey Farm), Harboring a Novel Gentamicin Resistance Mobile Element

    PubMed Central

    Huynh, Steven; Parker, Craig T.; Niedermeyer, Jeffrey A.; Kathariou, Sophia

    2016-01-01

    Multidrug resistance (MDR) in foodborne pathogens is a major food safety and public health issue. Here we describe whole-genome sequences of two MDR strains of Campylobacter jejuni and Campylobacter coli from turkey feces and a housefly from a turkey farm. Both strains harbor a novel chromosomal gentamicin resistance mobile element. PMID:27795285

  13. Characterisation of Phenotypic and Genotypic Antibiotic Resistance Profile of Enterococci from Cheeses in Turkey

    PubMed Central

    Yipel, Mustafa; Aslantaş, Özkan; Gündoğdu, Aycan

    2016-01-01

    The aim of this study was to determine the prevalence of enterococci in cheese samples and to characterize their antimicrobial resistance profiles as well as the associated resistance genes. A total of 139 enterococci were isolated from 99 cheese samples, the isolates were identified as E. faecalis (61.2%), E. faecium (15.1%), E. gallinarum (12.9%), E. durans (5.0%), E. casseliflavis (2.9%) and E. avium (2.9%). The most frequent antimicrobial resistance observed in enterococci isolates was to lincomycin (88.5%), followed by kanamycin (84.2%), gentamycin (low level, 51.1%), rifampin (46.8%) and tetracycline (33.8%). Among the isolates, the frequencies of high level gentamycin and streptomycin resistant enterococci strains were 2.2% and 5.8%, respectively. Apart from the mentioned antibiotics, low levels of resistance to ciprofloxacin, erythromycin and chloramphenicol were found. Moreover no resistance was observed against penicillin and ampicillin. The antimicrobial resistance genes including tetM, tetL, ermB, cat, aph(3’)-IIIa, ant(6)-Ia and aac(6’)-Ieaph(2”)-Ia were found in enterococci from Turkish cheese samples. In the current study, we provided data for antibiotic resistance and the occurrence of resistance genes among enterococci. Regulatory and quality control programs for milk and other dairy products from farms to retail outlets has to be established and strengthened to monitor trends in antimicrobial resistance among emerging food borne pathogens in Turkey. PMID:27433106

  14. Characterization of Enterococci from Food and Food-Related Settings.

    PubMed

    Soares-Santos, Verónica; Barreto, António Salvador; Semedo-Lemsaddek, Teresa

    2015-07-01

    Enterococcus species are ubiquitous in nature, exist at high levels in food, and can cause severe diseases in humans. Thus, surveillance of enterococci harboring antibiotic resistance and virulence factors in food and food-related environments is needed. In the present study, 89 samples from food and food processing surfaces were collected in a cheese factory, a swine slaughterhouse, and a supermarket, and 132 Enterococcus isolates were recovered. Most isolates were identified as E. faecalis, which is considered the most pathogenic member of this genus. Safety analysis covering antibiotic resistance revealed that all isolates were resistant to sulfamethoxazole-trimethoprim and sensitive to amoxicillin-clavulanate, ampicillin, ciprofloxacin, gentamicin, levofloxacin, linezolid, nitrofurantoin, or teicoplanin. More than half of the isolates were resistant to quinupristin-dalfopristin, tetracycline, and bacitracin, and less than half were resistant to the other antibiotics evaluated. Regarding virulence factors, 52% the isolates were beta-hemolytic, 39% were gelatinase producers, and 45% contained the gelE gene. For the remaining genes evaluated, efaAfs was detected in more than half of the isolates, and agg, esp, and efaAfm were found in less than half of the isolates. The present investigation revealed that food-related enterococci obtained from very different settings have multidrug resistance and virulence factors, highlighting the importance of effective surveillance networks to avoid the spread of putative pathogenic enterococci.

  15. Antimicrobial resistance profiles of dairy and clinical isolates and type strains of enterococci.

    PubMed

    de Fátima Silva Lopes, Maria; Ribeiro, Tânia; Abrantes, Marta; Figueiredo Marques, José Joaquim; Tenreiro, Rogério; Crespo, Maria Teresa Barreto

    2005-08-25

    The susceptibility to 30 antimicrobial agents was determined by the disk diffusion method for a collection of 172 enterococcal strains, including 96 isolates from dairy sources, 50 isolates of human and veterinary origin, and 26 reference strains from 24 different enterococcal species. Results were analysed by hierarchic numerical methods to cluster strains and to group antimicrobials according to similarity profiles. Resistance to 17 of the 30 antimicrobials showed to be correlated, leading to four groups reflecting the mode of action: quinolones (ofloxacin, enrofloxacin, ciprofloxacin and norfloxacin); macrolides (erythromycin, spiramycin), phenicols (cloramphenicol) and tetracyclins (tetracycline, oxytetracyclin); aminoglycosides (gentamicin, kanamycin) and lincosamides (clindamycin); penicillins (amoxicillin, ampicillin, penicillin G, piperacillin) and carbapenems (imipenem). Overall, the genus Enterococcus behaved as resistant to lincomycin, colistin, polimixin B and, with a few exceptions in dairy isolates, to methicillin. In general, all isolates were susceptible to vancomycin, cloramphenicol and fusidic acid. Clusters containing only dairy isolates were susceptible to the majority of antimicrobials tested, as opposed to clusters constituted only by clinical enterococcal isolates. Among the clinical isolates, 62% were highly multiresistant. Low level gentamicin resistance was found to be associated with clinical enterococci. Among dairy isolates, those that clustered with clinical isolates were both resistant to gentamicin and identified as Enterococcus faecalis. Resistance to macrolides, quinolones, penicillins and imipenem was found to be associated also with clinical environments, mainly with multiresistant isolates, contrary to what is generally agreed as a characteristic of the genus. Veterinary clinical isolates were mainly grouped with the multiresistant clinical human isolates. The 26 reference enterococcal strains were distributed in clusters with

  16. Antibiotic resistant enterococci-tales of a drug resistance gene trafficker.

    PubMed

    Werner, Guido; Coque, Teresa M; Franz, Charles M A P; Grohmann, Elisabeth; Hegstad, Kristin; Jensen, Lars; van Schaik, Willem; Weaver, Keith

    2013-08-01

    Enterococci have been recognized as important hospital-acquired pathogens in recent years, and isolates of E. faecalis and E. faecium are the third- to fourth-most prevalent nosocomial pathogen worldwide. Acquired resistances, especially against penicilin/ampicillin, aminoglycosides (high-level) and glycopeptides are therapeutically important and reported in increasing numbers. On the other hand, isolates of E. faecalis and E. faecium are commensals of the intestines of humans, many vertebrate and invertebrate animals and may also constitute an active part of the plant flora. Certain enterococcal isolates are used as starter cultures or supplements in food fermentation and food preservation. Due to their preferred intestinal habitat, their wide occurrence, robustness and ease of cultivation, enterococci are used as indicators for fecal pollution assessing hygiene standards for fresh- and bathing water and they serve as important key indicator bacteria for various veterinary and human resistance surveillance systems. Enterococci are widely prevalent and genetically capable of acquiring, conserving and disseminating genetic traits including resistance determinants among enterococci and related Gram-positive bacteria. In the present review we aimed at summarizing recent advances in the current understanding of the population biology of enterococci, the role mobile genetic elements including plasmids play in shaping the population structure and spreading resistance. We explain how these elements could be classified and discuss mechanisms of plasmid transfer and regulation and the role and cross-talk of enterococcal isolates from food and food animals to humans.

  17. Mechanisms of antibiotic resistance in enterococci

    PubMed Central

    Miller, William R; Munita, Jose M; Arias, Cesar A

    2015-01-01

    Multidrug-resistant (MDR) enterococci are important nosocomial pathogens and a growing clinical challenge. These organisms have developed resistance to virtually all antimicrobials currently used in clinical practice using a diverse number of genetic strategies. Due to this ability to recruit antibiotic resistance determinants, MDR enterococci display a wide repertoire of antibiotic resistance mechanisms including modification of drug targets, inactivation of therapeutic agents, overexpression of efflux pumps and a sophisticated cell envelope adaptive response that promotes survival in the human host and the nosocomial environment. MDR enterococci are well adapted to survive in the gastrointestinal tract and can become the dominant flora under antibiotic pressure, predisposing the severely ill and immunocompromised patient to invasive infections. A thorough understanding of the mechanisms underlying antibiotic resistance in enterococci is the first step for devising strategies to control the spread of these organisms and potentially establish novel therapeutic approaches. PMID:25199988

  18. LIGHT-INDUCED PROCESSES AFFECTING ENTEROCOCCI IN AQUATIC ENVIRONMENTS

    EPA Science Inventory

    Fecal indicator bacteria such as enterococci have been used to assess contamination of freshwater and marine environments by pathogenic microorganisms. Various past studies have shown that sunlight plays an important role in reducing concentrations of culturable enterococci and ...

  19. An Optimized Mouse Thigh Infection Model for Enterococci and Its Impact on Antimicrobial Pharmacodynamics

    PubMed Central

    Rodriguez, Carlos A.; Agudelo, Maria; Gonzalez, Javier M.; Vesga, Omar

    2014-01-01

    Negligible in vivo growth of enterococci and high-level dispersion of data have led to inaccurate estimations of antibiotic pharmacodynamics (PD). Here we improved an in vivo model apt for PD studies by optimizing the in vitro culture conditions for enterococci. The PD of vancomycin (VAN), ampicillin-sulbactam (SAM), and piperacillin-tazobactam (TZP) against enterococci were determined in vivo, comparing the following different conditions of inoculum preparation: aerobiosis, aerobiosis plus mucin, and anaerobiosis plus mucin. Drug exposure was expressed as the ratio of the area under the concentration-time curve for the free, unbound fraction of the drug to the MIC (fAUC/MIC) (VAN) or the time in a 24-h period that the drug concentration for the free, unbound fraction exceeded the MIC under steady-state pharmacokinetic conditions (fT>MIC) (SAM and TZP) and linked to the change in log10 CFU/thigh. Only anaerobiosis plus mucin enhanced the in vivo growth, yielding significant PD parameters with all antibiotics. In conclusion, robust in vivo growth of enterococci was crucial for better determining the PD of tested antibacterial agents, and this was achieved by optimizing the procedure for preparing the inoculum. PMID:25348523

  20. Abundance and characteristics of the recreational water quality indicator bacteria Escherichia coli and enterococci in gull faeces

    USGS Publications Warehouse

    Fogarty, L.R.; Haack, S.K.; Wolcott, M.J.; Whitman, R.L.

    2003-01-01

    Aims: To evaluate the numbers and selected phenotypic and genotypic characteristics of the faecal indicator bacteria Escherichia coli and enterococci in gull faeces at representative Great Lakes swimming beaches in the United States. Methods and Results: E. coli and enterococci were enumerated in gull faeces by membrane filtration. E. coli genotypes (rep-PCR genomic profiles) and E. coli (Vitek?? GNI+) and enterococci (API?? rapid ID 32 Strep and resistance to streptomycin, gentamicin, vancomycin, tetracycline and ampicillin) phenotypes were determined for isolates obtained from gull faeces both early and late in the swimming season. Identical E. coli genotypes were obtained only from single gull faecal samples but most faecal samples yielded more than one genotype (median of eight genotypes for samples with 10 isolates). E. coli isolates from the same site that clustered at ???85% similarity were from the same sampling date and shared phenotypic characteristics, and at this similarity level there was population overlap between the two geographically isolated beach sites. Enterococcus API?? profiles varied with sampling date. Gull enterococci displayed wide variation in antibiotic resistance patterns, and high-level resistance to some antibiotics. Conclusions: Gull faeces could be a major contributor of E. coli (105-109 CFU g-1) and enterococci (104-108 CFU g-1) to Great Lakes recreational waters. E. coli and enterococci in gull faeces are highly variable with respect to their genotypic and phenotypic characteristics and may exhibit temporal or geographic trends in these features. Significance and Impact of the Study: The high degree of variation in genotypic or phenotypic characteristics of E. coli or enterococci populations within gull hosts will require extensive sampling for adequate characterization, and will influence methods that use these characteristics to determine faecal contamination sources for recreational waters.

  1. Synergy between penicillin and gentamicin against enterococci.

    PubMed

    Winstanley, T G; Hastings, J G

    1990-04-01

    The role of active uptake in aminoglycoside activity against penicillin-treated enterococci was studied by viable counts and ATP determinations. Penicillin and gentamicin gave synergistic bactericidal and post-antibiotic effects (PAEs) which were partially reduced by sodium azide, an electron transport inhibitor, and totally blocked in the presence of both sodium azide and EDTA, which chelates divalent cations. EDTA and gentamicin showed marked synergy in both 'killing curve' and PAE experiments. This synergy was completely inhibited by sodium azide. The data indicate that the activity of gentamicin against enterococci that have been damaged by penicillin or EDTA is energy-dependent. This is consistent with present theories of gentamicin uptake via transportation drive by a protonmotive force.

  2. [Vancomycin resistant enterococci in the Netherlands].

    PubMed

    Leavis, H L; Willems, R J; Mascini, E M; Vandenbroucke-Grauls, C M; Bonten, M J

    2004-05-01

    Enterococci (Enterococcus faecalis and Enterococcus faecium) are relatively avirulent enteric bacteria that usually only cause infections in immunocompromised patients. Antimicrobial treatment, however, is hampered as enterococci are intrinsically resistant to many antibiotics. For years, vancomycin was considered the last available antibiotic. Plasmid-mediated resistance against vancomycin among enterococci was first described in the nineteen-eighties and since then incidences of infection caused by vancomycin-resistant enterococci (VRE) have increased dramatically, especially in the United States. In 2000, three outbreaks of VRE occurred in hospitals in the Netherlands and a set of infection-control measures was proposed to limit further transmission. These measures were based on the simultaneous isolation of VRE from multiple patients. All three outbreaks were controlled by these measures and no new outbreaks in Dutch hospitals have been reported since then. Epidemiological studies have shown that hospital outbreaks on three continents were caused by a subpopulation of E. faecium, which is characterized by the presence of a potential virulence gene (variant esp) and resistance to amoxicillin. This 'hospital strain' of E. faecium has probably been prevalent within hospital settings for some time, but only became clinically relevant when it had acquired vancomycin-resistance. Current advice is to implement the set of infection control measures formulated in 2000, only in those patients colonized by amoxicillin-resistant VRE. The potential dangers of VRE were recently underlined by the proven transmission of the vancomycin-resistance gene from VRE to methicillin-resistant Staphylococcus aureus (MRSA) in two patients in the United States. It is in the interest of the patients that prevalence of VRE and MRSA in Dutch hospitals should be kept as low as possible.

  3. Selective isolation of vancomycin-resistant enterococci.

    PubMed Central

    van Horn, K G; Gedris, C A; Rodney, K M

    1996-01-01

    Broth formulations of two media selective for enterococci, Enterococcel, M-Enterococcosel broths were supplemented with 6 micrograms of vancomycin per ml and evaluated for isolation of vancomycin-resistant enterococci (VRE). Each broth was challenged with various concentrations of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and vancomycin-susceptible and vancomycin-resistant enterococci and with 193 perianal specimens obtained from patients at risk in our institution for VRE colonization. Both the Enterococcosel and M-Enterococcus broths with vancomycin detected as few as 1 to 9 CFU of VRE while inhibiting growth of the other organisms tested. Enterococcus faecium organisms (MIC, > 256 micrograms/ml) were recovered from 66 perianal swab cultures in the enterococcosel-vancomycin broth, and VRE were recovered from 62 perianal swab cultures in the M-Enterococcus-vancomycin broth. Enterococcosel-vancomycin broth detected VRE in perianal specimens 48 h earlier than did M-Enterococcus-vancomycin broth. Enterococcosel broth with 6 micrograms of vancomycin per ml can be used for the rapid and selective isolation of VRE from surveillance specimens. PMID:8815109

  4. Diversity among multidrug-resistant enterococci.

    PubMed Central

    Murray, B. E.

    1998-01-01

    Enterococci are associated with both community- and hospital-acquired infections. Even though they do not cause severe systemic inflammatory responses, such as septic shock, enterococci present a therapeutic challenge because of their resistance to a vast array of antimicrobial drugs, including cell-wall active agents, all commercially available aminoglycosides, penicillin and ampicillin, and vancomycin. The combination of the latter two occurs disproportionately in strains resistant to many other antimicrobial drugs. The propensity of enterococci to acquire resistance may relate to their ability to participate in various forms of conjugation, which can result in the spread of genes as part of conjugative transposons, pheromone-responsive plasmids, or broad host-range plasmids. Enterococcal hardiness likely adds to resistance by facilitating survival in the environment (and thus enhancing potential spread from person to person) of a multidrug-resistant clone. The combination of these attributes within the genus Enterococcus suggests that these bacteria and their resistance to antimicrobial drugs will continue to pose a challenge. PMID:9452397

  5. Genome Sequencing Reveals the Environmental Origin of Enterococci and Potential Biomarkers for Water Quality Monitoring

    EPA Science Inventory

    Enterococci are common members of the gut microbiome and frequent causative agents of nosocomial infection. Because of their enteric lifestyle and ease of culturing, enterococci have been used worldwide as indicators of fecal pollution of waters. However, enterococci were recentl...

  6. Vancomycin resistant enterococci: from the hospital effluent to the urban wastewater treatment plant.

    PubMed

    Varela, Ana Rita; Ferro, Giovanna; Vredenburg, Jana; Yanık, Melike; Vieira, Lucas; Rizzo, Luigi; Lameiras, Catarina; Manaia, Célia M

    2013-04-15

    Vancomycin is an important antibiotic to treat serious nosocomial enterococci infections. Human activities, in particular those related with clinical practices performed in hospitals, can potentiate the transfer and selection of clinically-relevant resistant bacteria such as vancomycin resistant enterococci (VRE). Indeed, previous studies demonstrated the occurrence of VRE in urban wastewater treatment plants and related environments (e.g. sewage, rivers). In this study, the occurrence of VRE in a hospital effluent and in the receiving urban wastewater treatment plant was investigated. Vancomycin and ciprofloxacin resistant bacteria occurred in the hospital effluent and in raw municipal inflow at densities of 10(3) to 10(2) CFU mL(-1), being significantly more prevalent in the hospital effluent than in the urban wastewater. Most of the VRE isolated from the hospital effluent belonged to the species Enterococcus faecalis and Enterococcus faecium and presented multidrug-resistance phenotypes to ciprofloxacin, tetracycline, erythromycin, and high-level gentamicin. The same pattern was observed in clinical isolates and in enterococci isolated from the final effluent of the urban wastewater treatment plant. These results show that hospital effluents discharged into urban wastewater treatment plants may be a relevant source of resistance spread to the environment.

  7. OCCURRENCE OF INTRINSIC VANCOMYCIN RESISTANT ENTEROCOCCI IN ANIMAL FECES

    EPA Science Inventory

    A survey was conducted to determine the occurrence of vancomycin resistant enterococci (VRE) in animal and human fecal samples. Fecal samples from 14 animal species and humans were analyzed by quantitative culture for enterococci and VRE. Over 800 VRE isolates were characterize...

  8. Pore Water Transport of Enterococci out of Beach Sediments

    PubMed Central

    Phillips, Matthew C.; Solo-Gabriele, Helena M.; Reniers, Adrianus J. H. M.; Wang, John D.; Kiger, Russell T.; Abdel-Mottaleb, Noha

    2011-01-01

    Enterococci are used to evaluate the safety of beach waters and studies have identified beach sands as a source of these bacteria. In order to study and quantify the release of microbes from beach sediments, flow column systems were built to evaluate flow of pore water out of beach sediments. Results show a peak in enterococci (average of 10% of the total microbes in core) released from the sand core within one pore water volume followed by a marked decline to below detection. These results indicate that few enterococci are easily removed and that factors other than simple pore water flow control the release of the majority of enterococci within beach sediments. A significantly larger quantity and release of enterococci were observed in cores collected after a significant rain event suggesting the influx of fresh water can alter the release pattern as compared to cores with no antecedent rainfall. PMID:21945015

  9. Vancomycin-Resistant Enterococci and Bacterial Community Structure following a Sewage Spill into an Aquatic Environment

    PubMed Central

    Young, Suzanne; Nayak, Bina; Sun, Shan; Badgley, Brian D.; Rohr, Jason R.

    2016-01-01

    ABSTRACT Sewage spills can release antibiotic-resistant bacteria into surface waters, contributing to environmental reservoirs and potentially impacting human health. Vancomycin-resistant enterococci (VRE) are nosocomial pathogens that have been detected in environmental habitats, including soil, water, and beach sands, as well as wildlife feces. However, VRE harboring vanA genes that confer high-level resistance have infrequently been found outside clinical settings in the United States. This study found culturable Enterococcus faecium harboring the vanA gene in water and sediment for up to 3 days after a sewage spill, and the quantitative PCR (qPCR) signal for vanA persisted for an additional week. Culturable levels of enterococci in water exceeded recreational water guidelines for 2 weeks following the spill, declining about five orders of magnitude in sediments and two orders of magnitude in the water column over 6 weeks. Analysis of bacterial taxa via 16S rRNA gene sequencing showed changes in community structure through time following the sewage spill in sediment and water. The spread of opportunistic pathogens harboring high-level vancomycin resistance genes beyond hospitals and into the broader community and associated habitats is a potential threat to public health, requiring further studies that examine the persistence, occurrence, and survival of VRE in different environmental matrices. IMPORTANCE Vancomycin-resistant enterococci (VRE) are harmful bacteria that are resistant to the powerful antibiotic vancomycin, which is used as a last resort against many infections. This study followed the release of VRE in a major sewage spill and their persistence over time. Such events can act as a means of spreading vancomycin-resistant bacteria in the environment, which can eventually impact human health. PMID:27422829

  10. High-level vancomycin resistant Enterococcus faecium related to humans and pigs found in dust from pig breeding facilities.

    PubMed

    Braga, Teresa M; Pomba, Constança; Lopes, M Fátima Silva

    2013-01-25

    Environmental dust from animal breeding facilities was never screened for the presence of enterococci, nor of vancomycin-resistant enterococci (VRE), despite the possibility of being a vehicle of transmission of strains and antibiotic resistance genes between food-producing animals and man. Bio-security measures in pig facilities include disinfection with biocides to avoid the dissemination of opportunistic pathogenic bacteria, namely enterococci and in particular VRE. We thus undertook collection of enterococci and VRE in a representative number of breeding pig facilities in Portugal (n=171) and analyzed their susceptibility to benzalkonium chloride (BC) and chlorhexidine (CHX). A prevalence of 15% of VRE was found, with 6% high-level resistance found, and MIC values for CHX and BC were similar to those commonly found among enterococcal isolates from related environments, 8 μg/ml and 4 μg/ml, respectively. Among the isolated high-level vancomycin resistant Enterococcus faecium carrying the vanA genotype, we found multilocus sequence types closely related to pig and human isolates from European countries and Brazil. These results strongly advise constant surveillance of this environment and its inclusion in future epidemiologic studies on VRE.

  11. Studies on Media for Enumerating Enterococci in Frozen Vegetables.

    PubMed

    Splittstoesser, D F; Wright, R; Hucker, G J

    1961-07-01

    A study was made of the relative sensitivity and specificity of presumptive and confirmatory media for the most probable number enumeration of enterococci in frozen vegetables. Azide dextrose broth yielded the highest numbers of confirmable enterococci and its sensitivity was shown to be comparable to nonselective media. The use of ethyl violet azide broth as a confirmatory medium resulted in a significant number of false positive tests. Growth in broth containing 6.5% sodium chloride incubated at 45 C for 2 days was found to be a more specific confirmatory test for enterococci.

  12. Evaluation of antimicrobial resistance and virulence of enterococci from equipment surfaces, raw materials, and traditional cheeses.

    PubMed

    Gaglio, Raimondo; Couto, Natacha; Marques, Cátia; de Fatima Silva Lopes, Maria; Moschetti, Giancarlo; Pomba, Constança; Settanni, Luca

    2016-11-07

    Forty enterococci isolated along the production chains of three traditional cheeses (PDO Pecorino Siciliano, PDO Vastedda della Valle del Belìce, and Caciocavallo Palermitano) made in Sicily (southern Italy) were studied for the assessment of their antibiotic resistance and virulence by a combined phenotypic/genotypic approach. A total of 31 Enterococcus displayed resistance to at least one or more of the antimicrobials tested. The strains exhibited high percentages of resistance to erythromycin (52.5%), ciprofloxacin (35.0%), quinupristin-dalfopristin (20.0%), tetracycline (17.5%), and high-level streptomycin (5.0%). The presence of tet(M), cat(pC221), and aadE genes for resistance to tetracycline, chloramphenicol, and streptomycin, respectively, was registered in all strains with resistance phenotype. The erm(B) gene was not detected in any erythromycin-resistant strain. The Enterococcus strains were further tested by PCR for the presence of virulence genes, namely, gelE, asa1, efaA, ace, and esp. Twenty strains were positive for all virulence genes tested. Among the enterococci isolated from final cheeses, three strains (representing 33.3% of total cheese strains) were sensible to all antimicrobials tested and did not carry any virulence factor. Although this study confirmed that the majority of dairy enterococci are vectors for the dissemination of antimicrobial resistance and virulence genes, only two strains showed a high resistance to aminoglycosides, commonly administered to combat enterococci responsible for human infections. Furthermore, the presence of the strains E. casseliflavus FMAC163, E. durans FMAC134B, and E. faecium PON94 without risk determinants, found at dominating levels over the Enterococcus populations in the processed products, stimulates further investigations for their future applications in cheese making. All strains devoid of the undesired traits were isolated from stretched cheeses. Thus, this cheese typology represents an

  13. High-Level Radioactive Waste.

    ERIC Educational Resources Information Center

    Hayden, Howard C.

    1995-01-01

    Presents a method to calculate the amount of high-level radioactive waste by taking into consideration the following factors: the fission process that yields the waste, identification of the waste, the energy required to run a 1-GWe plant for one year, and the uranium mass required to produce that energy. Briefly discusses waste disposal and…

  14. RPython high-level synthesis

    NASA Astrophysics Data System (ADS)

    Cieszewski, Radoslaw; Linczuk, Maciej

    2016-09-01

    The development of FPGA technology and the increasing complexity of applications in recent decades have forced compilers to move to higher abstraction levels. Compilers interprets an algorithmic description of a desired behavior written in High-Level Languages (HLLs) and translate it to Hardware Description Languages (HDLs). This paper presents a RPython based High-Level synthesis (HLS) compiler. The compiler get the configuration parameters and map RPython program to VHDL. Then, VHDL code can be used to program FPGA chips. In comparison of other technologies usage, FPGAs have the potential to achieve far greater performance than software as a result of omitting the fetch-decode-execute operations of General Purpose Processors (GPUs), and introduce more parallel computation. This can be exploited by utilizing many resources at the same time. Creating parallel algorithms computed with FPGAs in pure HDL is difficult and time consuming. Implementation time can be greatly reduced with High-Level Synthesis compiler. This article describes design methodologies and tools, implementation and first results of created VHDL backend for RPython compiler.

  15. Prevalence of virulence and resistance to antibiotics in pathogenic enterococci isolated from mastitic cows

    PubMed Central

    WU, Xiaohu; HOU, Shubao; ZHANG, Quanwei; MA, Youji; ZHANG, Yong; KAN, Wei; ZHAO, Xingxu

    2016-01-01

    The prevalence of enterococci was examined in 280 milk samples collected from dairy cattle diagnosed with mastitis in three provinces of western China. Sixty strains of enterococci were isolated, and the species were determined based on their biochemical characters and 16S rRNA sequences. Resistance to seven antibiotic agents, frequency of seven virulence genes and pathogenicity in Kunming mice were tested to evaluate biological risks. The correlation between the number of virulence genes and pathogenicity in Kunming mice was also evaluated. The 60 isolates were allocated to Enterococcus hirae (68.3%), E. faecium (25.0%), E. mundtii (3.3%) and E. durans (3.3%). A total of 83.3% of the isolates were resistant to penicillin, whereas 15.0% were resistant to ampicillin, 15.0% to vancomycin, 6.7% to tetracycline and 25.0% to ciprofloxacin. Moreover, isolates exhibited 50.0% and 21.7% resistance to high levels of gentamycin and streptomycin, respectively. The gene asa1 was detected in all enterococcal isolates, whereas 66.7% of strains harbored three or more virulence factors and 56.7% were asa1-ccf-gelE-positive. In pathogenicity tests, isolates harboring numerous virulence factors did not show greater invasiveness than isolates harboring fewer virulence traits against Kunming mice. In conclusion, the number of virulence factors does not appear to predict the risk of enterococcal infection. Isolates were commonly resistant to penicillin and sporadically to ampicillin and vancomycin. These results suggest that the use of gentamycin, streptomycin and ciprofloxacin against enterococci should be avoided in mastitic cows. Additionally, the results demonstrate that the majority of isolates are sensitive to tetracycline. PMID:27476730

  16. The CMS High Level Trigger

    NASA Astrophysics Data System (ADS)

    Trocino, Daniele

    2014-06-01

    The CMS experiment has been designed with a two-level trigger system: the Level-1 Trigger, implemented in custom-designed electronics, and the High-Level Trigger (HLT), a streamlined version of the CMS offline reconstruction software running on a computer farm. A software trigger system requires a tradeoff between the complexity of the algorithms running with the available computing power, the sustainable output rate, and the selection efficiency. We present the performance of the main triggers used during the 2012 data taking, ranging from simple single-object selections to more complex algorithms combining different objects, and applying analysis-level reconstruction and selection. We discuss the optimisation of the trigger and the specific techniques to cope with the increasing LHC pile-up, reducing its impact on the physics performance.

  17. Virulence factors and bacteriocins in faecal enterococci of wild boars.

    PubMed

    Poeta, Patricia; Igrejas, Gilberto; Costa, Daniela; Sargo, Roberto; Rodrigues, Jorge; Torres, Carmen

    2008-10-01

    The production of antimicrobial, haemolytic and gelatinase activities was tested in 67 enterococci (39 E. faecium, 24 E. hirae, 2 E. faecalis, and 2 Enterococcus spp.), recovered from faecal samples of wild boars. In addition, the presence of genes encoding bacteriocin and virulence factors was also analysed by PCR and sequencing. Production of antimicrobial activity was checked in all enterococci against 9 indicator bacteria and it was detected in 11 E. faecium isolates (16.5%); eight and two of them harboured the genes encoding enterocin A + enterocin B and enterocin L50A/B, respectively. Sixty-seven per cent of our enterococci harboured different combinations of genes of the cyl operon, but none of them contained the complete cyl L(L)L(S)ABM operon, necessary for cytolysin expression. The presence of gel E gene, associated with the fsr ABC locus, was identified in 4 E. faecium and two E. faecalis isolates, exhibiting all of them gelatinase activity. beta -hemolytic activity was not found in our isolates. Both cpd and ace genes, encoding respectively the accessory colonisation factor and pheromone, were detected in two E. faecalis isolates, and the hyl gene, encoding hyalorunidase, in two E. faecium isolates, one of them gelatinase-positive. Genes encoding bacteriocins and virulence factors are widely disseminated among faecal enterococci of wild boars and more studies should be carried out to know the global distribution of these determinants in enterococci of different ecosystems.

  18. Emergence and nosocomial transmission of ampicillin-resistant enterococci.

    PubMed Central

    Boyce, J M; Opal, S M; Potter-Bynoe, G; LaForge, R G; Zervos, M J; Furtado, G; Victor, G; Medeiros, A A

    1992-01-01

    Between 1986 and 1988, the incidence of ampicillin-resistant enterococci increased sevenfold at a university-affiliated hospital. Forty-three patients acquired nosocomial infections with ampicillin-resistant enterococci, most of which were also resistant to mezlocillin, piperacillin, and imipenem. An analysis of plasmid and chromosomal DNAs of isolates revealed that the increase was due to an epidemic of 19 nosocomial infections that yielded closely related strains of Enterococcus faecium and to a significant increase in the incidence of nonepidemic, largely unrelated strains of ampicillin-resistant enterococci. The nonepidemic strains were identified as E. faecium, E. raffinosus, E. durans, and E. gallinarum. A logistic regression analysis revealed that patients with nonepidemic resistant strains were 16 times more likely than controls to have received preceding therapy with imipenem. In our institution, the increase in the incidence of ampicillin-resistant enterococci appears to be due to the selection of various strains of resistant enterococci by the use of imipenem and to the nosocomial transmission of E. faecium and E. raffinosus. Images PMID:1510390

  19. Evaluation of Chromogenic Media in Detection of Vancomycin Resistant Enterococci

    PubMed Central

    S., Vijaya; S.T., Santhya; M.K., Yashaswini; S., Megha

    2014-01-01

    Introduction: Vancomycin resistant Enterococci have become important nosocomial pathogens. So it is necessary to monitor continuously such infections in the hospitals. Materials and Methods: A total of 100 Enterococci isolated from 4489 various clinical samples were speciated and antibiogram was done according to standard laboratory methods. The efficacy of CHROMagarTM VRE (France) and Hicrome VRE (Himedia) in detecting VRE was evaluated using E- test (Himedia). Results: Hicrome VRE and CHROMagarTM VRE showed sensitivity of 100% and specificity of 99% as compared to E-test. Conclusion: In the present study VRE was not isolated. Prudent use of vancomycin and continuous surveillance for VRE will prevent the emergence of vancomycin resistant Enterococci in the locality in future. Identification of VRE by chromogenic media is rapid, easy to perform, cost effective compared to technically demanding, time consuming and costly conventional method. PMID:25584221

  20. Optimizing High Level Waste Disposal

    SciTech Connect

    Dirk Gombert

    2005-09-01

    If society is ever to reap the potential benefits of nuclear energy, technologists must close the fuel-cycle completely. A closed cycle equates to a continued supply of fuel and safe reactors, but also reliable and comprehensive closure of waste issues. High level waste (HLW) disposal in borosilicate glass (BSG) is based on 1970s era evaluations. This host matrix is very adaptable to sequestering a wide variety of radionuclides found in raffinates from spent fuel reprocessing. However, it is now known that the current system is far from optimal for disposal of the diverse HLW streams, and proven alternatives are available to reduce costs by billions of dollars. The basis for HLW disposal should be reassessed to consider extensive waste form and process technology research and development efforts, which have been conducted by the United States Department of Energy (USDOE), international agencies and the private sector. Matching the waste form to the waste chemistry and using currently available technology could increase the waste content in waste forms to 50% or more and double processing rates. Optimization of the HLW disposal system would accelerate HLW disposition and increase repository capacity. This does not necessarily require developing new waste forms, the emphasis should be on qualifying existing matrices to demonstrate protection equal to or better than the baseline glass performance. Also, this proposed effort does not necessarily require developing new technology concepts. The emphasis is on demonstrating existing technology that is clearly better (reliability, productivity, cost) than current technology, and justifying its use in future facilities or retrofitted facilities. Higher waste processing and disposal efficiency can be realized by performing the engineering analyses and trade-studies necessary to select the most efficient methods for processing the full spectrum of wastes across the nuclear complex. This paper will describe technologies being

  1. High Level Aminoglycoside Resistance and Distribution of Aminoglycoside Resistant Genes among Clinical Isolates of Enterococcus Species in Chennai, India

    PubMed Central

    Padmasini, Elango; Padmaraj, R.; Ramesh, S. Srivani

    2014-01-01

    Enterococci are nosocomial pathogen with multiple-drug resistance by intrinsic and extrinsic mechanisms. Aminoglycosides along with cell wall inhibitors are given clinically for treating enterococcal infections. 178 enterococcal isolates were analyzed in this study. E. faecalis is identified to be the predominant Enterococcus species, along with E. faecium, E. avium, E. hirae, E. durans, E. dispar and E. gallinarum. High level aminoglycoside resistance (HLAR) by MIC for gentamicin (GM), streptomycin (SM) and both (GM + SM) antibiotics was found to be 42.7%, 29.8%, and 21.9%, respectively. Detection of aminoglycoside modifying enzyme encoding genes (AME) in enterococci was identified by multiplex PCR for aac(6′)-Ie-aph(2′′)-Ia; aph(2′′)-Ib; aph(2′′)-Ic; aph(2′′)-Id and aph(3′)-IIIa genes. 38.2% isolates carried aac(6′)-Ie-aph(2′′)-Ia gene and 40.4% isolates carried aph(3′)-IIIa gene. aph(2′′)-Ib; aph(2′′)-Ic; aph(2′′)-Id were not detected among our study isolates. aac(6′)-Ie-aph(2′′)-Ia and aph(3′)-IIIa genes were also observed in HLAR E. durans, E. avium, E. hirae, and E. gallinarum isolates. This indicates that high level aminoglycoside resistance genes are widely disseminated among isolates of enterococci from Chennai. PMID:24672306

  2. Vancomycin-resistance transferability from VanA enterococci to Staphylococcus aureus.

    PubMed

    de Niederhäusern, Simona; Bondi, Moreno; Messi, Patrizia; Iseppi, Ramona; Sabia, Carla; Manicardi, Giuliano; Anacarso, Immacolata

    2011-05-01

    In last decade methicillin-resistant Staphylococcus aureus with high level of vancomycin-resistance (VRSA) have been reported and generally the patients with VRSA infection were also infected with a vancomycin-resistant Enterococcus (VRE). Considering that the high level of vancomycin-resistance in VRSA isolates seems to involve the horizontal transfer of Tn1546 transposon containing vanA gene from coinfecting VRE strains, the authors have studied the "in vitro" conjugative transfer of this resistance from VanA enterococci to S. aureus. Out of 25 matings performed combining five vancomycin-resistant enterococci as donors (three Enterococcus faecalis and two Enterococcus faecium), and five S. aureus as recipients, all clinical isolates, two have been successful using E. faecalis as donor. The transfer of vancomycin-resistance was confirmed by vanA gene amplification in both transconjugants and the resistance was expressed at lower levels (MIC 32 μg/ml) in comparison with the respective VRE donors (MIC > 128 μg/ml). The vancomycin-resistance of trasconjugants was maintained even after subsequent overnight passages on MSA plates containing subinhibitory levels of vancomycin. This study shows that the vanA gene transfer can be achieved through techniques "in vitro" without the use of laboratory animals employed, in the only similar experiment previously carried out by other authors, as substrate for the trasconjugant growth. Moreover, in that previous experiment, contrary to this study, the vancomycin resistant S. aureus trasconjugants were selected on erythromycin agar and not by direct vancomycin agar selection.

  3. Development of a rapid, one-step screening method for the isolation of presumptive proteolytic enterococci.

    PubMed

    Graham, Ken; Rea, Rosemary; Simpson, Paul; Stack, Helena

    2017-01-01

    Enterococci show higher proteolytic activities than other lactic acid bacteria and thus have received considerable attention in scientific literature in recent years. Proteolytic enzymes of enterococci have warranted the use of some species as starter, adjuncts or protective cultures and as probiotics, while in some strains they have also been linked with virulence. Consequently, the isolation and identification of proteolytic enterococci is becoming of increasing interest and importance. However, current screening methods for proteolytic enterococci can be time consuming, requiring a two-step procedure which may take up to 96h. This study describes a method, utilising Kanamycin Skim Milk Aesculin Azide (KSMEA) agar, for the isolation of proteolytic enterococci in one-step, thereby significantly reducing screening time. KSMEA combines the selective properties of Kanamycin Aesculin Azide Agar (KAA) with skim milk powder for the detection of proteolytic enterococci. Enterococci produced colonies with a black halo on KSMEA which were accompanied by a zone of clearing in the media when enterococci were proteolytic. KSMEA medium retained the selectivity of KAA, while proteolytic enterococci were easily distinguished from non-proteolytic enterococci when two known strains were propagated on KSMEA. KSMEA also proved effective at isolating and detecting enterococci in raw milk, faeces and soil. Isolates recovered from the screen were confirmed as enterococci using genus-specific primers. Proteolytic enterococci were present in the raw milk sample only and were easily distinguishable from non-proteolytic enterococci and other microorganisms. Therefore, KSMEA provides a rapid, one-step screening method for the isolation of presumptive proteolytic enterococci.

  4. DETECTION OF FECAL ENTEROCOCCI USING A REAL TIME PCR METHOD

    EPA Science Inventory

    In spite of their importance in public health, the detection of fecal enterococci is performed via culturing methods that are time consuming and that are subject to inaccuracies that relate to their culturable status. In order to address these problems, a real time PCR (TaqMan) ...

  5. OCCURRENCE OF VANCOMYCIN RESISTANT ENTEROCOCCI IN ANIMAL FECES

    EPA Science Inventory

    A survey was conducted to determine the occurrence of vancomycin resistant Enterococci (VRE) in animal and human fecal samples. A selective agar mEI, and mEI supplemented with 4 micrograms/ml vancomycin was used in a membrane filtration procedure to determine quantitative levels ...

  6. Molecular characterization of antimicrobial resistance in enterococci and Escherichia coli isolates from European wild rabbit (Oryctolagus cuniculus).

    PubMed

    Silva, Nuno; Igrejas, Gilberto; Figueiredo, Nicholas; Gonçalves, Alexandre; Radhouani, Hajer; Rodrigues, Jorge; Poeta, Patrícia

    2010-09-15

    A total of 44 Escherichia coli and 64 enterococci recovered from 77 intestinal samples of wild European rabbits in Portugal were analyzed for resistance to antimicrobial agents. Resistance in E. coli isolates was observed for ampicillin, tetracycline, sulfamethoxazole/trimethoprim, streptomycin, gentamicin, tobramycin, nalidixic acid, ciprofloxacin and chloramphenicol. None of the E. coli isolates produced extended-spectrum beta-lactamases (ESBLs). The bla(TEM), aadA, aac(3)-II, tet(A) and/or tet(B), and the catA genes were demonstrated in all ampicillin, streptomycin, gentamicin, tetracycline, and chloramphenicol-resistant isolates respectively, and the sul1 and/or sul2 and/or sul3 genes in 4 of 5 sulfamethoxazole/trimethoprim resistant isolates. Of the enterococcal isolates, Enterococcus faecalis was the most prevalent detected species (39 isolates), followed by E. faecium (21 isolates) and E. hirae (4 isolates). More than one-fourth (29.7%) of the isolates were resistant to tetracycline; 20.3% were resistant to erythromycin, 14.1% were resistant to ciprofloxacin and 10.9% were resistant to high-level-kanamycin. Lower level of resistance (<10%) was detected for ampicillin, quinupristin/dalfopristin and high-level-gentamicin, -streptomycin. No vancomycin-resistance was detected in the enterococci isolates. Resistance genes detected included aac(6')-aph(2''), ant(6)-Ia, tet(M) and/or tet(L) in all gentamicin, streptomycin and tetracycline-resistant isolates respectively. The aph(3')-IIIa gene was detected in 6 of 7 kanamycin-resistant isolates, the erm(B) gene in 11 of 13 erythromycin-resistant isolates and the vat(D) gene in the quinupristin/dalfopristin-resistant E. faecium isolate. This survey showed that faecal bacteria such as E. coli and enterococci of wild rabbits could be a reservoir of antimicrobial resistance genes.

  7. Detection of glycopeptide resistance genes in enterococci by multiplex PCR

    PubMed Central

    Bhatt, Puneet; Sahni, A.K.; Praharaj, A.K.; Grover, Naveen; Kumar, Mahadevan; Chaudhari, C.N.; Khajuria, Atul

    2014-01-01

    Background Vancomycin Resistant Enterococci (VRE) are a major cause of nosocomial infections. There are various phenotypic and genotypic methods of detection of glycopeptide resistance in enterococci. This study utilizes multiplex PCR for reliable detection of various glycopeptides resistance genes in VRE. Method This study was conducted to detect and to assess the prevalence of vancomycin resistance among enterococci isolates. From October 2011 to June 2013, a total of 96 non-repetitive isolates of enterococci from various clinical samples were analyzed. VRE were identified by Kirby Bauer disc diffusion method with Clinical and Laboratory Standards Institute (CLSI) guidelines. Minimum inhibitory concentration (MIC) of all isolates for vancomycin and teicoplanin was determined by E-test. Multiplex PCR was carried out for all enterococci isolates using six sets of primers. Results Out of 96 isolates, 14 (14.6%) were found to be resistant to vancomycin by vancomycin E-test method (MIC ≥32 μg/ml). Out of these 14 isolates, 13 were also resistant to teicoplanin (MIC ≥16 μg/ml). VanA gene was detected in all the 14 isolates by Multiplex PCR. One of the PCR amplicons was sent for sequencing and the sequence received was submitted in the GenBank (GenBank accession no. KF181100). Conclusion Prevalence of VRE in this study was 14.6%. Multiplex PCR is a robust, sensitive and specific technique, which can be used for rapid detection of various glycopeptide resistance genes. Rapid identification of patients infected or colonized with VRE is essential for implementation of appropriate control measures to prevent their spread. PMID:25609863

  8. Antimicrobial resistance and virulence genes in enterococci from wild game meat in Spain.

    PubMed

    Guerrero-Ramos, Emilia; Cordero, Jorge; Molina-González, Diana; Poeta, Patrícia; Igrejas, Gilberto; Alonso-Calleja, Carlos; Capita, Rosa

    2016-02-01

    A total of 55 enterococci (45 Enterococcus faecium, 7 Enterococcus faecalis, and three Enterococcus durans) isolated from the meat of wild game animals (roe deer, boar, rabbit, pheasant, and pigeon) in North-Western Spain were tested for susceptibility to 14 antimicrobials by the disc diffusion method. All strains showed a multi-resistant phenotype (resistance to between three and 10 antimicrobials). The strains exhibited high percentages of resistance to erythromycin (89.1%), tetracycline (67.3%), ciprofloxacin (92.7%), nitrofurantoin (67.3%), and quinupristin-dalfopristin (81.8%). The lowest values (9.1%) were observed for high-level resistance to gentamicin, kanamycin, and streptomycin. The average number of resistances per strain was 5.8 for E. faecium isolates, 7.9 for E. faecalis, and 5.7 for E. durans. Genes encoding antimicrobial resistance and virulence were studied by polymerase chain reaction. A total of 15 (57.7%) of the 26 vancomycin-resistant isolates harboured the vanA gene. Other resistance genes detected included vanB, erm(B) and/or erm(C), tet(L) and/or tet(M), acc(6')-aph(2″), and aph(3')-IIIa in strains resistant to vancomycin, erythromycin, tetracycline, gentamicin, and kanamycin, respectively. Specific genes of the Tn5397 transposon were detected in 54.8% of the tet(M)-positive enterococci. Nine virulence factors (gelE, agg, ace, cpd, frs, esp, hyl, efaAfs and efaAfm) were studied. All virulence genes, with the exception of the frs gene, were found to be present in the enterococcal isolates. At least one virulence gene was detected in 20.0% of E. faecium, 71.4% of E. faecalis and 33.3% of E. durans isolates, with ace and cpd being the most frequently detected genes (6 isolates each). This suggests that wild game meat might play a role in the spreading through the food chain of enterococci with antimicrobial resistance and virulence determinants to humans.

  9. Contribution of sand-associated enterococci to dry weather water quality.

    PubMed

    Halliday, Elizabeth; Ralston, David K; Gast, Rebecca J

    2015-01-06

    Culturable enterococci and a suite of environmental variables were collected during a predominantly dry summer at a beach impacted by nonpoint source pollution. These data were used to evaluate sands as a source of enterococci to nearshore waters, and to assess the relationship between environmental factors and dry-weather enterococci abundance. Best-fit multiple linear regressions used environmental variables to explain more than half of the observed variation in enterococci in water and dry sands. Notably, during dry weather the abundance of enterococci in dry sands at the mean high-tide line was significantly positively related to sand moisture content (ranging from <1-4%), and the daily mean ENT in water could be predicted by a linear regression with turbidity alone. Temperature was also positively correlated with ENT abundance in this study, which may indicate an important role of seasonal warming in temperate regions. Inundation by spring tides was the primary rewetting mechanism that sustained culturable enterococci populations in high-tide sands. Tidal forcing modulated the abundance of enterococci in the water, as both turbidity and enterococci were elevated during ebb and flood tides. The probability of samples violating the single-sample maximum was significantly greater when collected during periods with increased tidal range: spring ebb and flood tides. Tidal forcing also affected groundwater mixing zones, mobilizing enterococci from sand to water. These data show that routine monitoring programs using discrete enterococci measurements may be biased by tides and other environmental factors, providing a flawed basis for beach closure decisions.

  10. [In vitro susceptibility of Enterococcus strains to high level aminoglycosides and heavy metals].

    PubMed

    Nakipoğlu, Yaşar; Gümüş, Defne; Sertel Selale, Deniz; Küçüker, Mine Ang

    2009-10-01

    The widespread use of antimicrobial agents in the hospitals and environmental contamination with heavy metals are increasingly related to resistance progression in microorganisms. The aim of this study was to investigate the resistance of enterococci to high level aminoglycosides and some heavy metals [lead (Pb+2), cadmium (Cd+2), mercury (Hg+2), arsenic (As+5)]. A total of 39 Enterococcus strains, isolated from stool and rectal swabs of hospitalized patients were included to the study. Twenty of the strains were resistant to glycopeptides (11 were resistant to vancomycin + teicoplanin and 9 were resistant to only vancomycin). Disk diffusion method was performed to determine the high level resistance to aminoglycosides (gentamicin 120 microg and streptomycin 300 microg), and agar dilution method was used to detect the sensitivities of the strains against different concentrations (0.005-20 mM) of heavy metals. Since there is no specified minimum inhibitory concentration (MIC) breakpoints for heavy metals, resistance criteria described in previous studies were used. Accordingly, enterococci which exhibited MIC > or = 1 mM for lead and cadmium, MIC > or = 0.1 mM for mercury, and MIC > or = 10 mM for arsenic were accepted as resistant. High level aminoglycoside (HLAG) resistance rates were found as 91% (10/11) for vancomycin (V) + teicoplanin (T) resistant and 42% (8/19) for glycopeptide susceptible strains. While all of the isolates were resistant to lead (100%), arsenic (2.6%) and mercury (2.6%) resistance was detected in one isolate for each metal. No cadmium resistance has been detected. In our study, enterococci have exhibited seven different resistance profiles (10 strains were resistant to V + T + HLAG + Pb; 1 was resistant to V + T + Pb; 1 was resistant to V + As + Pb; 1 was resistant to HLAG + Hg + Pb; 8 were resistant to V + Pb; 7 were resistant to HLAG + Pb; 11 were only resistant to Pb). Resistance to antibiotics (aminoglycosides and/or vancomycin and

  11. Vancomycin-resistant enterococci (VRE) in meat and environmental samples.

    PubMed

    Messi, Patrizia; Guerrieri, Elisa; de Niederhäusern, Simona; Sabia, Carla; Bondi, Moreno

    2006-03-15

    We investigated the spread of vancomycin-resistant enterococci (VRE) in strains from meat and environmental samples and the location of glycopeptide-resistance determinants in VanA isolates. VRE and VSE (vancomycin-sensitive enterococci) resistance patterns to six antimicrobials were also evaluated. A total of 59 meat isolates (35%) and 119 environmental isolates (26.5%) were glycopeptide resistant enterococci. In particular, 10.7% meat isolates belonged to the VanA, 8.3% to VanB and 16% to VanC phenotypes. Environmental samples presented 0.7% VanA, 14.5% VanB, and 11.4% VanC strains. Evident differences were not observed among the resistance patterns of VRE and VSE isolates. Neither an important difference was observed comparing the resistance patterns in enterococci from meat and environment. In particular a low incidence of beta-lactamic resistant strains was found, whereas high rates of resistance were observed for streptomycin (85.7% and 92.8%), kanamycin (79.7% and 96%) and gentamycin (85.1% and 91.7%). An intermediate rate of resistant bacteria emerged for erythromycin (35.1% and 10.5%). All VanA isolates independent of origin had more plasmids with different molecular weights. PCR amplification of the 732 bp fragment in plasmids from the VanA strains confirmed affiliation to the vanA gene cluster and the extrachromosomal location of the glycopeptide-resistance determinants. Our study suggests that food and environment play a potential role as reservoirs of resistance determinants, prompting the need to undertake epidemiological and molecular studies to evaluate the mobility of these genes.

  12. Culture media for enterococci and group D-streptococci.

    PubMed

    Reuter, G

    1992-10-01

    Lancefield group D-streptococci are contaminants of various food commodities, especially those of animal origin. They encompass the new genus Enterococcus comprising 13 known species and some species of streptococci which have their habitat in the intestine of animals, e.g. Streptococcus bovis, suis and equinus. The serologically based grouping may no longer constitute the best definition for streptococci from the food chain. Food hygiene monitoring systems using enterococci as indicators need reliable methods for selective cultivation and identification of marker strains. Up to now more than 100 modifications of selective media have been described for isolating streptococci or enterococci from various specimens. The selection of a medium requires either experience or consultation. It depends on the kind of specimen, the method of cultivation (plate count or membrane filter) and whether or not the habitat is heavily contaminated with other organisms. The choice of media is made more difficult as commercial versions of the same culture medium may vary in recipe and/or performance from producer to producer. Therefore, reviewing the literature may help in the choice of medium and confirmation tests. The selectivity and productivity of some commonly used or cited media are reported here, partly based on our own experience: citrate azide tween carbonate agar (CATC), kanamycin aesculin azide agar (KAA) and M-enterococcus agar (ME) including earlier results with aesculin bile azide agar (ABA), and thallous acetate tetrazolium glucose agar (TITG). No medium was completely selective for all group D-streptococci or for all enterococci but some media were highly selective for a single Enterococcus species, e.g., for E. faecalis which serves as indicator of human pollution. Confirmatory tests must be carried out when experience in the evaluation procedure is limited. Selective media for enterococci should be used only after or while checking in parallel their selectivity and

  13. Genetic Basis for Daptomycin Resistance in Enterococci ▿ † ‡

    PubMed Central

    Palmer, Kelli L.; Daniel, Anu; Hardy, Crystal; Silverman, Jared; Gilmore, Michael S.

    2011-01-01

    The emergence of multidrug-resistant enterococci as a leading cause of hospital-acquired infection is an important public health concern. Little is known about the genetic mechanisms by which enterococci adapt to strong selective pressures, including the use of antibiotics. The lipopeptide antibiotic daptomycin is approved to treat Gram-positive bacterial infections, including those caused by enterococci. Since its introduction, resistance to daptomycin by strains of Enterococcus faecalis and Enterococcus faecium has been reported but is still rare. We evolved daptomycin-resistant strains of the multidrug-resistant E. faecalis strain V583. Based on the availability of a fully closed genome sequence for V583, we used whole-genome resequencing to identify the mutations that became fixed over short time scales (∼2 weeks) upon serial passage in the presence of daptomycin. By comparison of the genome sequences of the three adapted strains to that of parental V583, we identified seven candidate daptomycin resistance genes and three different mutational paths to daptomycin resistance in E. faecalis. Mutations in one of the seven candidate genes (EF0631), encoding a putative cardiolipin synthase, were found in each of the adapted E. faecalis V583 strains as well as in daptomycin-resistant E. faecalis and E. faecium clinical isolates. Alleles of EF0631 from daptomycin-resistant strains are dominant in trans and confer daptomycin resistance upon a susceptible host. These results demonstrate a mechanism of enterococcal daptomycin resistance that is genetically distinct from that occurring in staphylococci and indicate that enterococci possessing alternate EF0631 alleles are selected for during daptomycin therapy. However, our analysis of E. faecalis clinical isolates indicates that resistance pathways independent from mutant forms of EF0631 also exist. PMID:21502617

  14. Vancomycin resistant enterococci in farm animals – occurrence and importance

    PubMed Central

    Nilsson, Oskar

    2012-01-01

    The view on enterococci has over the years shifted from harmless commensals to opportunistic but important pathogens mainly causing nosocomial infections. One important part of this development is the emergence of vancomycin resistance enterococci (VRE). The term VRE includes several combinations of bacterial species and resistance genes of which the most clinically important is Enterococcus faecium with vanA type vancomycin resistance. This variant is also the most common VRE among farm animals. The reason for VRE being present among farm animals is selection by extensive use of the vancomycin analog avoparcin for growth promotion. Once the use of avoparcin was discontinued, the prevalence of VRE among farm animals decreased. However, VRE are still present among farm animals and by spread via food products they could potentially have a negative impact on public health. This review is based on the PhD thesis Vancomycin Resistant Enterococci in Swedish Broilers – Emergence, Epidemiology and Elimination and makes a short summary of VRE in humans and food producing animals. The specific situation regarding VRE in Swedish broiler production is also mentioned. PMID:22957131

  15. Evidence for growth of enterococci in municipal oxidation ponds, obtained using antibiotic resistance analysis.

    PubMed

    Moriarty, Elaine; Nourozi, Fariba; Robson, Beth; Wood, David; Gilpin, Brent

    2008-12-01

    The Christchurch wastewater treatment plant uses a series of six oxidation ponds to reduce the bacterial load of treated effluent before it is discharged into the local estuary. To ensure that this discharge does not adversely affect water quality in the receiving environment, local regulations specify maximum levels in the discharge for a number of parameters, including enterococci. Between 2001 and 2006, regulations required fewer than 300 enterococci per 100 ml in summer. During this period, the discharge intermittently exceeded this limit, with unexplained levels of enterococci of up to 180,000/100 ml. Characterization of these enterococci by antibiotic resistance analysis showed that enterococci sampled over 4 months had almost identical resistance profiles. In contrast, enterococci from raw sewage and wildfowl from around the oxidation ponds had a diverse range of antibiotic resistance profiles that could be distinguished from each other and also from those of enterococci from the discharge. The hypothesis of a clonal nature of the enterococci in the discharge was supported by molecular genotype analysis, suggesting that these bacteria may have replicated in the pond environment rather than being reflective of breakthrough in the sewage treatment process or the result of recent wildfowl inputs to the ponds. This study highlights the usefulness of antibiotic resistance analysis in identifying this phenomenon and is the first report of apparent replication of a specific type of enterococci in an oxidation pond environment.

  16. Colonization Rate and Risk Factors of Vancomycin-Resistant Enterococci among Patients Received Hematopoietic Stem Cell Transplantation in Shiraz, Southern Iran

    PubMed Central

    Kaveh, M.; Bazargani, A.; Ramzi, M.; Sedigh Ebrahim-Saraie, H.; Heidari, H.

    2016-01-01

    Background: Infections caused by antimicrobial-resistant bacteria are associated with increased mortality and health care costs. Enterococci have been recognized as a clinically important pathogen in hospitalized patients. Vancomycin-resistant enterococci (VRE) infections cause significant morbidity and mortality among patients undergoing transplantation. Objective: To identify epidemiology of VRE colonization and related risk factors among patients with hematological malignancies after hematopoietic stem cell transplantation (HSCT). Methods: This cross-sectional study was performed on 42 patients who underwent bone-marrow transplantation between July 2013 and March 2014. A stool sample was taken from each patient 3–5 days after transplantation and cultured on appropriate media. Suspected colonies of enterococci were detected to species level by their culture characteristics, biochemical reactions and molecular features. VRE were confirmed via phenotypic and genotypic methods. Results: VRE were detected in 14 (33%) of studied samples. 10 (71%) of the detected VRE isolates were identified as high level vancomycin-resistant E. faecium with minimum inhibitory concentration (MIC) of ≥256 μg/mL of vancomycin; 3 isolates were E. galinarum and 1 was E. casseliflavus with an MIC of 8–16 μg/mL. VanA was dominant phenotype and all VRE isolates with high-level of vancomycin resistance had vanA gene. VRE isolation was mostly observed in patients with acute lymphoblastic leukemia (ALL) than other diseases. Moreover, antibiotic prophylaxis and hospitalization were independent risk factors for acquisition of VRE after transplantation. Conclusion: We found high level of vancomycin-resistance in E. faecium isolates obtained from HSCT patients. The vancomycin-resistant isolates of E. faecium had vanA and/or simultaneously vanB genes. PMID:28078058

  17. Mechanisms of antimicrobial resistance and genetic relatedness among enterococci isolated from dogs and cats in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: In this study, mechanisms of antimicrobial resistance and genetic relatedness among resistant enterococci from dogs and cats in the United States were determined. Methods and Results: Enterococci resistant to chloramphenicol, ciprofloxacin, erythromycin, gentamicin, kanamycin, streptomycin,...

  18. Evaluation of Enterolert for enumeration of enterococci in recreational waters.

    PubMed Central

    Budnick, G E; Howard, R T; Mayo, D R

    1996-01-01

    Enterolert (IDEXX Laboratories Inc., Westbrook, Maine), a semiautomated, most probable number method for enumeration of enterococci, was compared with the standard membrane filter method by parallel testing of 138 marine and freshwater recreational bathing water samples. No statistically significant difference and a strong linear correlation were found between methods. Culturing of 501 Enterolert test wells resulted in false-positive and false-negative rates of 5.1 and 0.4%, respectively. Less time for setup, incubation (24 versus 48 h), and reading of Enterolert permits more efficient monitoring of recreational bathing areas. PMID:8837446

  19. The zoonotic potential of daptomycin non-susceptible enterococci.

    PubMed

    Kelesidis, T

    2015-02-01

    Daptomycin non-susceptible Enterococcus (DNSE) is an emerging clinical problem. Little is known about how de novo DNSE infections develop or the risk factors associated with them. Determining risk factors associated with de novo DNSE infections will aid in understanding the mechanisms of daptomycin non-susceptibility. Humans in contact with animals worldwide are at risk of carriage of multidrug-resistant bacteria. Herein, I review the scientific evidence that supports the hypothesis that transport of daptomycin non-susceptibility genes between animals and humans may be a possible mechanism for development of de novo daptomycin non-susceptibility in enterococci.

  20. FINGERPRINTING OF FECAL ENTEROCOCCI BY MATRIX ASSISTED LASER DESORPTION IONIZATION MASS SPECTROMETRY

    EPA Science Inventory

    The fecal enterococci group has been suggested as an indicator of fecal contamination in freshwater and marine water systems and as a potential target for bacterial source tracking of fecal pollution. While many studies have described the diversity of enterococci in environmenta...

  1. Occurrence of putative pathogenicity islands in enterococci from distinct species and of differing origins.

    PubMed

    Semedo-Lemsaddek, Teresa; Barreto-Crespo, Maria Teresa; Tenreiro, Rogério

    2009-11-01

    Enterococci isolated from ewe's milk and cheese, clinical isolates of human and veterinary origins, and reference strains obtained from culture collections were screened for the occurrence of putative pathogenicity island (PAIs). Results obtained after PCR amplification and hybridization point toward PAI dissemination among enterococci of diverse origins (food/clinical) and species (Enterococcus faecalis/non-E. faecalis).

  2. DETECTION OF INTRINSIC VANCOMYCIN RESISTANT ENTEROCOCCI IN ANIMAL AND HUMAN FECES

    EPA Science Inventory

    A survey was conducted to determine the occurrence of vancomycin resistant enterococci (VRE) in animal and human fecal samples. Fecal samples from 14 animal species and humans were analyzed by quantitative culture for enterococci and VRE. Over 800 VRE isolates were characterize...

  3. A RAPID, SPECIFIC MEMBRANE FILTRATION PROCEDURE FOR ENUMERATION OF ENTEROCOCCI IN RECREATIONAL WATER

    EPA Science Inventory

    A two-step membrane filter (MP) method with mE medium, upon which the membrane must be incubated for 48 h and then transferred to a substrate medium to differentiate enterococci, is recommended by the U.S.Environmental Protection Agency to measure enterococci in fresh and marine ...

  4. A Software Architecture for High Level Applications

    SciTech Connect

    Shen,G.

    2009-05-04

    A modular software platform for high level applications is under development at the National Synchrotron Light Source II project. This platform is based on client-server architecture, and the components of high level applications on this platform will be modular and distributed, and therefore reusable. An online model server is indispensable for model based control. Different accelerator facilities have different requirements for the online simulation. To supply various accelerator simulators, a set of narrow and general application programming interfaces is developed based on Tracy-3 and Elegant. This paper describes the system architecture for the modular high level applications, the design of narrow and general application programming interface for an online model server, and the prototype of online model server.

  5. Performance of Vitek 2 for antimicrobial susceptibility testing of Staphylococcus spp. and Enterococcus spp.

    PubMed

    Bobenchik, April M; Hindler, Janet A; Giltner, Carmen L; Saeki, Sandra; Humphries, Romney M

    2014-02-01

    Vitek 2 (bioMérieux, Inc., Durham, NC) is a widely used commercial antimicrobial susceptibility testing system. We compared MIC results obtained by Vitek 2 to those obtained by the Clinical and Laboratory Standards Institute (CLSI) broth microdilution (BMD) reference method for 134 staphylococcal and 84 enterococcal clinical isolates. Nineteen agents were evaluated, including all those available on Vitek 2 for testing staphylococci and enterococci. The resistance phenotypes tested included methicillin-resistant Staphylococcus aureus (MRSA) (n = 58), S. aureus with inducible clindamycin resistance (ICR) (n = 30), trimethoprim-sulfamethoxazole-resistant MRSA (n = 10), vancomycin-resistant Enterococcus (n = 37), high-level gentamicin-resistant Enterococcus (n = 15), linezolid-resistant Enterococcus (n = 5), and daptomycin-nonsusceptible Enterococcus faecalis (n = 6). For the staphylococci, there was 98.9% categorical agreement (CA). There was one very major error (VME) for gentamicin in a Staphylococcus hominis isolate, six VMEs for inducible clindamycin in S. aureus isolates, and two major errors (ME) for daptomycin in an S. aureus and a Staphylococcus epidermidis isolate. For enterococci, there was 97.3% CA. Two VMEs were observed for daptomycin in isolates of E. faecalis and 2 ME, 1 for high-level gentamicin resistance and 1 for nitrofurantoin, in E. faecium isolates. Overall, there was 98.3% CA and 99% essential agreement for the testing of staphylococci and enterococci by the Vitek 2. With the exception of detecting ICR in S. aureus, Vitek 2 performed reliably for antimicrobial susceptibility testing of staphylococci and enterococci.

  6. Contribution of Sand-Associated Enterococci to Dry Weather Water Quality

    PubMed Central

    2015-01-01

    Culturable enterococci and a suite of environmental variables were collected during a predominantly dry summer at a beach impacted by nonpoint source pollution. These data were used to evaluate sands as a source of enterococci to nearshore waters, and to assess the relationship between environmental factors and dry-weather enterococci abundance. Best-fit multiple linear regressions used environmental variables to explain more than half of the observed variation in enterococci in water and dry sands. Notably, during dry weather the abundance of enterococci in dry sands at the mean high-tide line was significantly positively related to sand moisture content (ranging from <1–4%), and the daily mean ENT in water could be predicted by a linear regression with turbidity alone. Temperature was also positively correlated with ENT abundance in this study, which may indicate an important role of seasonal warming in temperate regions. Inundation by spring tides was the primary rewetting mechanism that sustained culturable enterococci populations in high-tide sands. Tidal forcing modulated the abundance of enterococci in the water, as both turbidity and enterococci were elevated during ebb and flood tides. The probability of samples violating the single-sample maximum was significantly greater when collected during periods with increased tidal range: spring ebb and flood tides. Tidal forcing also affected groundwater mixing zones, mobilizing enterococci from sand to water. These data show that routine monitoring programs using discrete enterococci measurements may be biased by tides and other environmental factors, providing a flawed basis for beach closure decisions. PMID:25479559

  7. Linking non-culturable (qPCR) and culturable enterococci densities with hydrometeorological conditions

    USGS Publications Warehouse

    Byappanahalli, Muruleedhara N.; Whitman, Richard L.; Shively, Dawn A.; Nevers, Meredith B.

    2010-01-01

    Quantitative polymerase chain reaction (qPCR) measurement of enterococci has been proposed as a rapid technique for assessment of beach water quality, but the response of qPCR results to environmental conditions has not been fully explored. Culture-based E. coli and enterococci have been used in empirical predictive models to characterize their responses to environmental conditions and to increase monitoring frequency and efficiency. This approach has been attempted with qPCR results only in few studies. During the summer of 2006, water samples were collected from two southern Lake Michigan beaches and the nearby river outfall (Burns Ditch) and were analyzed for enterococci by culture-based and non-culture-based (i.e., qPCR) methods, as well as culture-based E. coli. Culturable enterococci densities (log CFU/100 ml) for the beaches were significantly correlated with enterococci qPCR cell equivalents (CE) (R = 0.650, P N = 32). Enterococci CE and CFU densities were highest in Burns Ditch relative to the beach sites; however, only CFUs were significantly higher (P R = 0.565, P N = 32). Culturable E. coli and enterococci densities were significantly correlated (R = 0.682, P N = 32). Regression analyses suggested that enterococci CFU could be predicted by lake turbidity, Burns Ditch discharge, and wind direction (adjusted R2 = 0.608); enterococci CE was best predicted by Burns Ditch discharge and log-transformed lake turbidity × wave height (adjusted R2 = 0.40). In summary, our results show that analytically, the qPCR method compares well to the non-culture-based method for measuring enterococci densities in beach water and that both these approaches can be predicted by hydrometeorological conditions. Selected predictors and model results highlight the differences between the environmental responses of the two method endpoints and the potentially high variance in qPCR results

  8. Prevalence, diversity and characterization of enterococci from three coraciiform birds.

    PubMed

    Splichalova, Petra; Svec, Pavel; Ghosh, Anuradha; Zurek, Ludek; Oravcova, Veronika; Radimersky, Tomas; Bohus, Mirko; Literak, Ivan

    2015-05-01

    Coraciiform birds hoopoe (Upupa epops), common kingfisher (Alcedo atthis) and European roller (Coracius garrulus) were examined for enterococci in their cloacae and uropygial glands. The enterococcal isolates were identified at the species level using several genomic and proteomic methods, screened for antibiotic susceptibility and genotyped by pulsed-field gel electrophoresis (PFGE). Clonality of isolates from the common kingfisher was also assessed by multi-locus sequence typing (MLST). Using selective media, putative enterococcal isolates (n = 117) were recovered from 74% (32 out of a total of 43) of the bird samples and 114 isolates were confirmed as enterococci. Overall, among the total of 6 different species detected, Enterococcus faecalis was dominant (59%) in all three bird species. The second most frequently isolated species was Enterococcus casseliflavus (32%). PFGE revealed great diversity of strains from different bird species and anatomic location. Closely related strains were found only from nestlings from the same nest. No genes conferring resistance to vancomycin (vanA, vanB, vanC1 and van C2/C3) or erythromycin (erm A, ermB and mefA/E) were detected. MLST analysis and eBURST clustering revealed that sequence types of E. faecalis from the common kingfisher were identical to those of isolates found previously in water, chickens, and humans.

  9. Modified Lactic Acid Bacteria Detect and Inhibit Multiresistant Enterococci

    PubMed Central

    2015-01-01

    We designed Lactococcus lactis to detect Enterococcus faecalis. Upon detection, L. lactis produce and secrete antienterococcal peptides. The peptides inhibit enterococcal growth and reduce viability of enterococci in the vicinity of L. lactis. The enterococcal sex pheromone cCF10 serves as the signal for detection. Expression vectors derived from pCF10, a cCF10-responsive E. faecalis sex-pheromone conjugative plasmid, were engineered in L. lactis for the detection system. Recombinant host strains were engineered to express genes for three bacteriocins, enterocin A, hiracin JM79 and enterocin P, each with potent antimicrobial activity against E. faecalis. Sensitive detection and specific inhibition occur both in agar and liquid media. The engineered L. lactis also inhibited growth of multidrug-resistant E. faecium strains, when induced by cCF10. The presented vectors and strains can be components of a toolbox for the development of alternative antibiotic technologies targeting enterococci at the site of infection. PMID:24896372

  10. High-Level Application Framework for LCLS

    SciTech Connect

    Chu, P; Chevtsov, S.; Fairley, D.; Larrieu, C.; Rock, J.; Rogind, D.; White, G.; Zalazny, M.; /SLAC

    2008-04-22

    A framework for high level accelerator application software is being developed for the Linac Coherent Light Source (LCLS). The framework is based on plug-in technology developed by an open source project, Eclipse. Many existing functionalities provided by Eclipse are available to high-level applications written within this framework. The framework also contains static data storage configuration and dynamic data connectivity. Because the framework is Eclipse-based, it is highly compatible with any other Eclipse plug-ins. The entire infrastructure of the software framework will be presented. Planned applications and plug-ins based on the framework are also presented.

  11. PAIRWISE BLENDING OF HIGH LEVEL WASTE (HLW)

    SciTech Connect

    CERTA, P.J.

    2006-02-22

    The primary objective of this study is to demonstrate a mission scenario that uses pairwise and incidental blending of high level waste (HLW) to reduce the total mass of HLW glass. Secondary objectives include understanding how recent refinements to the tank waste inventory and solubility assumptions affect the mass of HLW glass and how logistical constraints may affect the efficacy of HLW blending.

  12. High-level radioactive wastes. Supplement 1

    SciTech Connect

    McLaren, L.H.

    1984-09-01

    This bibliography contains information on high-level radioactive wastes included in the Department of Energy's Energy Data Base from August 1982 through December 1983. These citations are to research reports, journal articles, books, patents, theses, and conference papers from worldwide sources. Five indexes, each preceded by a brief description, are provided: Corporate Author, Personal Author, Subject, Contract Number, and Report Number. 1452 citations.

  13. Are clinical laboratories in California accurately reporting vancomycin-resistant enterococci?

    PubMed

    Rosenberg, J; Tenover, F C; Wong, J; Jarvis, W; Vugia, D J

    1997-10-01

    In order to determine whether hospital-based clinical laboratories conducting active surveillance for vancomycin-resistant enterococci in three San Francisco Bay area counties (San Francisco, Alameda, and Contra Costa counties) were accurately reporting vancomycin resistance, five vancomycin-resistant enterococcal strains and one vancomycin-susceptible beta-lactamase-producing enterococcus were sent to 31 of 32 (97%) laboratories conducting surveillance. Each strain was tested by the laboratory's routine antimicrobial susceptibility testing method. An Enterococcus faecium strain with high-level resistance to vancomycin (MIC, 512 microg/ml) was correctly reported as resistant by 100% of laboratories; an E. faecium strain with moderate-level resistance (MIC, 64 microg/ml) was correctly reported as resistant by 91% of laboratories; two Enterococcus faecalis strains with low-level resistance (MICs, 32 microg/ml) were correctly reported as resistant by 97 and 56% of laboratories, respectively. An Enterococcus gallinarum strain with intrinsic low-level resistance (MIC, 8 microg/ml) was correctly reported as intermediate by 50% of laboratories. A beta-lactamase-producing E. faecalis isolate was correctly identified as susceptible to vancomycin by 100% of laboratories and as resistant to penicillin and ampicillin by 68 and 44% of laboratories, respectively; all 23 (74%) laboratories that tested for beta-lactamase recognized that it was a beta-lactamase producer. This survey indicated that for clinically significant enterococcal isolates, laboratories in the San Francisco Bay area have problems in detecting low- to moderate-level but not high-level vancomycin resistance. Increasing accuracy of detection and prompt reporting of these isolates and investigation of cases are the next steps in the battle for control of the spread of vancomycin resistance.

  14. Enterococci as indicator of potential growth of Salmonella in fresh minced meat at retail.

    PubMed

    Hansen, Tina Beck; Nielsen, Niels L; Christensen, Bjarke Bak; Aabo, Søren

    2016-10-01

    The present study had the purpose of demonstrating a positive correlation between enterococci and Salmonella in minced pork and beef. Data from 2001 to 2002 from retail minced pork and beef in Denmark were used and the association between concentration of enterococci and prevalence and concentration of Salmonella was examined. A total of 2187 and 2747 samples of minced pork and beef, respectively, were collected from butcher shops and supermarkets throughout the country. In pork, 2.1% of all samples were positive for Salmonella whereas 1.5% of beef samples were positive. Among samples with ≥100 CFU/g of enterococci, prevalence of Salmonella positive samples was 3.4%, which was significantly higher than 1.2% observed in minced meat with less than 100 CFU/g of enterococci (P < 0.001). A positive association between occurrence of enterococci and presence of Salmonella in retail minced meat was supported as both prevalence and concentration of Salmonella in positive samples increased with increasing concentrations of enterococci in minced meat. From our data, we suggest that minced meat containing more than 500 enterococci per gram is suspected of having been exposed to temperatures allowing growth of Salmonella. This is to our knowledge the first report, which links presence of an indicator to potential growth of Salmonella.

  15. Enterococci as probiotics and their implications in food safety.

    PubMed

    Franz, Charles M A P; Huch, Melanie; Abriouel, Hikmate; Holzapfel, Wilhelm; Gálvez, Antonio

    2011-12-02

    Enterococci belong to the lactic acid bacteria (LAB) and they are of importance in foods due to their involvement in food spoilage and fermentations, as well as their utilisation as probiotics in humans and slaughter animals. However, they are also important nosocomial pathogens that cause bacteraemia, endocarditis and other infections. Some strains are resistant to many antibiotics and possess virulence factors such as adhesins, invasins, pili and haemolysin. The role of enterococci in disease has raised questions on their safety for use in foods or as probiotics. Studies on the incidence of virulence traits among enterococcal strains isolated from food showed that some can harbour virulence traits, but it is also thought that virulence is not the result of the presence of specific virulence determinants alone, but is rather a more intricate process. Specific genetic lineages of hospital-adapted strains have emerged, such as E. faecium clonal complex (CC) 17 and E. faecalis CC2, CC9, CC28 and CC40, which are high risk enterococcal clonal complexes. These are characterised by the presence of antibiotic resistance determinants and/or virulence factors, often located on pathogenicity islands or plasmids. Mobile genetic elements thus are considered to play a major role in the establishment of problematic lineages. Although enterococci occur in high numbers in certain types of fermented cheeses and sausages, they are not deliberately added as starter cultures. Some E. faecium and E. faecalis strains are used as probiotics and are ingested in high numbers, generally in the form of pharmaceutical preparations. Such probiotics are administered to treat diarrhoea, antibiotic-associated diarrhoea or irritable bowel syndrome, to lower cholesterol levels or to improve host immunity. In animals, enterococcal probiotics are mainly used to treat or prevent diarrhoea, for immune stimulation or to improve growth. From a food microbiological point of view, the safety of the

  16. High-Level Waste Melter Study Report

    SciTech Connect

    Perez Jr, Joseph M; Bickford, Dennis F; Day, Delbert E; Kim, Dong-Sang; Lambert, Steven L; Marra, Sharon L; Peeler, David K; Strachan, Denis M; Triplett, Mark B; Vienna, John D; Wittman, Richard S

    2001-07-13

    At the Hanford Site in Richland, Washington, the path to site cleanup involves vitrification of the majority of the wastes that currently reside in large underground tanks. A Joule-heated glass melter is the equipment of choice for vitrifying the high-level fraction of these wastes. Even though this technology has general national and international acceptance, opportunities may exist to improve or change the technology to reduce the enormous cost of accomplishing the mission of site cleanup. Consequently, the U.S. Department of Energy requested the staff of the Tanks Focus Area to review immobilization technologies, waste forms, and modifications to requirements for solidification of the high-level waste fraction at Hanford to determine what aspects could affect cost reductions with reasonable long-term risk. The results of this study are summarized in this report.

  17. Sodium chloride-esculin hydrolysis test for rapid identification of enterococci.

    PubMed

    Qadri, S M; Flournoy, D J; Qadri, S G

    1987-06-01

    The ability of enterococci to cause severe disease in humans and their relative resistance to chemotherapeutic agents make it desirable to rapidly differentiate these organisms from other streptococci. We developed and evaluated a test that within 2 h distinguishes enterococci from other alpha-, beta-, or nonhemolytic streptococci in a buffered solution containing 0.2% esculin and 5% sodium chloride. All 239 strains of enterococci tested gave a positive reaction within 2 h, whereas 95 of 96 isolates of other streptococci remained negative at 4 h.

  18. Prevalence, seasonality, and growth of enterococci in raw and pasteurized milk in Victoria, Australia.

    PubMed

    McAuley, Catherine M; Britz, Margaret L; Gobius, Kari S; Craven, Heather M

    2015-12-01

    This study investigated the prevalence, seasonality, and species variety of enterococci present in raw milk factory silos and pasteurized milk in 3 dairying regions in Victoria, Australia, over a 1-yr period. Additionally, the growth ability of thermoduric enterococci isolated in this study (Enterococcus faecalis, E. faecium, E. hirae, and E. durans) was determined in milk at temperatures likely to occur during storage, transport, and distribution, and before domestic consumption (4 and 7°C). Enterococci were detected in 96% of 211 raw milk samples, with an average count of 2.48 log10 cfu/mL. Counts were significantly lower in winter than summer (average 1.84 log10 cfu/mL) and were different between factories but not regions. Enterococcus faecalis was the most prevalent species isolated from raw milk in every factory, comprising between 61.5 and 83.5% of enterococcal species across each season. Enterococci were detected in lower numbers in pasteurized milk than in raw milk and were below the limit of detection on spread plates (<10 cfu/mL) after factory pasteurization. Residual viable cells were only detected following enrichment using 100-mL samples of milk, with 20.8% of the samples testing positive; this equated to a decrease in the average raw milk enterococci count of >4 log10 cfu/mL following pasteurization. Although E. faecalis predominated in raw milk and E. durans was found in only 2.9% of raw milk samples, E. durans was the most prevalent species detected in pasteurized milk. The detection of enterococci in the pasteurized milk did not correlate with higher enterococci counts in the raw milk. This suggested that the main enterococci populations in raw milk were heat-sensitive and that thermoduric enterococci survived pasteurization in a small numbers of instances. All of the thermoduric enterococci that were assessed for growth at likely refrigeration temperatures were able to grow at both 4 and 7°C in sterile milk, with generation times of 35 to 41h

  19. Action and interaction of penicillin and gentamicin on enterococci.

    PubMed Central

    Soriano, F; Greenwood, D

    1979-01-01

    The action and interaction of benzylpenicillin and gentamicin on Streptococcus faecalis was studied using mainly turbidimetric methods. The minimum antibacterial concentration (MAC) of each antibiotic lay considerably below the conventionally determined minimum inhibitory concentration, and levels of the two agents exceeding the MAC were necessary in order to obtain a synergic interaction. Evidence was obtained that gentamicin interfered with bacterial lysis induced by penicillin, and this suggests that the aminoglycoside is responsible for the bactericidal activity of the combination, the role of the penicillin being solely to facilitate access of the aminoglycoside to its target site. Our findings do not, however, fully support the generally held view that the increased permeability of enterococci to aminoglycosides is due to penicillin-induced cell wall damage. 'Persisters'--cells surviving prolonged exposure to the optimum lethal concentration of penicillin--were not killed by subsequent exposure to gentamicin if the penicillin was removed but were killed if the penicillin remained present. PMID:117025

  20. Phenotypic and Genotypic Characterization of Bacteriocinogenic Enterococci Against Clostridium botulinum.

    PubMed

    Shehata, Awad A; Tarabees, Reda; Basiouni, Shereen; Gamil, Mahmoud; Kamal, Ahmed S; Krüger, Monika

    2016-12-02

    The present study aimed to characterize Enterococcus faecalis (n = -6) and Enterococcus faecium (n = 1) isolated from healthy chickens to find a novel perspective probiotic candidate that antagonize Clostridium botulinum types A, B, D, and E. The isolated enterococci were characterized based on phenotypic properties, PCR, and matrix-assisted laser desorption/ionization time of flight (MALDI-TOF). The virulence determinants including hemolytic activity on blood agar, gelatinase activity, sensitivity to vancomycin, and presence of gelatinase (gelE) and enterococcal surface protein (esp) virulence genes were investigated. Also, the presence of enterocin structural genes enterocin A, enterocin B, enterocin P, enterocin L50A/B, bacteriocin 31, enterocin AS48, enterocin 1071A/1071B, and enterocin 96 were assessed using PCR. Lastly, the antagonistic effect of the selected Enterococcus spp. on the growth of C. botulinum types A, B, D, and E was studied. The obtained results showed that four out of six E. faecalis and one E. faecium proved to be free from the tested virulence markers. All tested enterococci strains exhibited more than one of the tested enterocin. Interestingly, E. faecalis and E. faecium significantly restrained the growth of C. botulinum types A, B, D, and E. In conclusion, although, the data presented showed that bacteriocinogenic Enterococcus strains lacking of virulence determinants could be potentially used as a probiotic candidate against C. botulinum in vitro; however, further investigations are still urgently required to verify the beneficial effects of the tested Enterococcus spp. in vivo.

  1. Virulence factors genes in enterococci isolated from beavers (Castor fiber).

    PubMed

    Lauková, Andrea; Strompfová, Viola; Kandričáková, Anna; Ščerbová, Jana; Semedo-Lemsaddek, Teresa; Miltko, Renata; Belzecki, Grzegorz

    2015-03-01

    Only limited information exists concerning the microbiota in beaver (Castor fiber). This study has been focused on the virulence factors genes detection in enterococci from beavers. In general, animals are not affected by enterococcal infections, but they can be a reservoir of, e.g. pathogenic strains. Moreover, detection of virulence factors genes in enterococci from beavers was never tested before. Free-living beavers (12), male and female (age 4-5 years) were caught in the north-east part of Poland. Sampling of lower gut and faeces was provided according to all ethical rules for animal handling. Samples were treated using a standard microbiological method. Pure bacterial colonies were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) identification system. Virulence factors genes-gelE (gelatinase), agg (aggregation), cylA (cytolysin A), efaAfs (adhesin Enterococcus faecalis), efaAfm (adhesin Enterococcus faecium) and esp (surface protein) were tested by PCR. Moreover, gelatinase and antibiotic phenotypes were tested. Species detected were Enterococcus thailandicus, E. faecium, E. faecalis and Enterococcus durans. In literature, enterococcal species distribution was never reported yet up to now. Strains were mostly sensitive to antibiotics. Vancomycin-resistant E. faecalis EE9Tr1 possess cylA, efaAfs, esp and gelE genes. Strains were aggregation substance genes absent. Adhesin E. faecium (efaAfm) gene was detected in two of three E. faecium strains, but it was present also in E. thailandicus. Esp gene was present in EE9Tr1 and E. durans EDTr92. The most detected were gelE, efaAfm genes; in EF 4Hc1 also gelatinase phenotype was found. Strains with virulence factors genes will be tested for their sensitivity to antimicrobial enterocins.

  2. EAP high-level product architecture

    NASA Astrophysics Data System (ADS)

    Gudlaugsson, T. V.; Mortensen, N. H.; Sarban, R.

    2013-04-01

    EAP technology has the potential to be used in a wide range of applications. This poses the challenge to the EAP component manufacturers to develop components for a wide variety of products. Danfoss Polypower A/S is developing an EAP technology platform, which can form the basis for a variety of EAP technology products while keeping complexity under control. High level product architecture has been developed for the mechanical part of EAP transducers, as the foundation for platform development. A generic description of an EAP transducer forms the core of the high level product architecture. This description breaks down the EAP transducer into organs that perform the functions that may be present in an EAP transducer. A physical instance of an EAP transducer contains a combination of the organs needed to fulfill the task of actuator, sensor, and generation. Alternative principles for each organ allow the function of the EAP transducers to be changed, by basing the EAP transducers on a different combination of organ alternatives. A model providing an overview of the high level product architecture has been developed to support daily development and cooperation across development teams. The platform approach has resulted in the first version of an EAP technology platform, on which multiple EAP products can be based. The contents of the platform have been the result of multi-disciplinary development work at Danfoss PolyPower, as well as collaboration with potential customers and research institutions. Initial results from applying the platform on demonstrator design for potential applications are promising. The scope of the article does not include technical details.

  3. Python based high-level synthesis compiler

    NASA Astrophysics Data System (ADS)

    Cieszewski, Radosław; Pozniak, Krzysztof; Romaniuk, Ryszard

    2014-11-01

    This paper presents a python based High-Level synthesis (HLS) compiler. The compiler interprets an algorithmic description of a desired behavior written in Python and map it to VHDL. FPGA combines many benefits of both software and ASIC implementations. Like software, the mapped circuit is flexible, and can be reconfigured over the lifetime of the system. FPGAs therefore have the potential to achieve far greater performance than software as a result of bypassing the fetch-decode-execute operations of traditional processors, and possibly exploiting a greater level of parallelism. Creating parallel programs implemented in FPGAs is not trivial. This article describes design, implementation and first results of created Python based compiler.

  4. Service Oriented Architecture for High Level Applications

    SciTech Connect

    Chu, Chungming; Chevtsov, Sergei; Wu, Juhao; Shen, Guobao; /Brookhaven

    2012-06-28

    Standalone high level applications often suffer from poor performance and reliability due to lengthy initialization, heavy computation and rapid graphical update. Service-oriented architecture (SOA) is trying to separate the initialization and computation from applications and to distribute such work to various service providers. Heavy computation such as beam tracking will be done periodically on a dedicated server and data will be available to client applications at all time. Industrial standard service architecture can help to improve the performance, reliability and maintainability of the service. Robustness will also be improved by reducing the complexity of individual client applications.

  5. FACTORS INFLUENCING LIGHT-INDUCED MORTALITY OF ENTEROCOCCI IN SEDIMENT SUSPENSIONS

    EPA Science Inventory

    Contamination of recreational waters by pathogenic microorganisms occurs through complex, poorly understood interactions involving variable microbial sources, hydrodynamic transport, arid microbial fate processes. Fecal indicator bacteria such as enterococci have been used to ass...

  6. NEW TARGET AND CONTROL ASSAYS FOR QUANTITATIVE POLYMERASE CHAIN REACTION (QPCR) ANALYSIS OF ENTEROCOCCI IN WATER

    EPA Science Inventory

    Enterococci are frequently monitored in water samples as indicators of fecal pollution. Attention is now shifting from culture based methods for enumerating these organisms to more rapid molecular methods such as QPCR. Accurate quantitative analyses by this method requires highly...

  7. The effect of sodium azide concentration on the recovery of enterococci from water.

    PubMed

    Fricker, C R; Eldred, B J

    2014-06-01

    The ability of Slanetz and Bartley medium to recover chlorine-stressed enterococci has been studied. Results showed that chlorine injury significantly affected the ability of Slanetz and Bartley medium to recover enterococci while lower concentrations of sodium azide in the same basal medium allowed their recovery. However, reducing the concentration of sodium azide considerably reduced the specificity making it unsuitable for use in the routine examination of water. A non-azide-containing medium, Enterolert(®)-DW appeared to be able to recover injured and non-injured enterococci with similar efficiency. The data presented here suggest that further work is required to improve the recovery of chlorine-injured enterococci by Slanetz and Bartley medium.

  8. Differential decay of Enterococci and Escherichia coli originating from two fecal pollution sources

    EPA Science Inventory

    Using in situ subtropical aquatic mesocosms, fecal source (cattle manure versus sewage) was shown to be the most important contributor to differential loss in viability of fecal indicator bacteria (FIB), specifically enterococci in freshwater and Escherichia coli in marine habita...

  9. Thymidylate Limitation Potentiates Cephalosporin Activity toward Enterococci via an Exopolysaccharide-Based Mechanism.

    PubMed

    Hoff, Jessica S; Kristich, Christopher J

    2016-06-17

    Multidrug resistant enterococci are major causes of nosocomial infections. Prior therapy with cephalosporins increases the risk of developing an enterococcal infection due to the intrinsic resistance of enterococci to these antibiotics. While progress has been made toward understanding the genetic and biochemical mechanisms of cephalosporin resistance, available data indicate that as-yet-unidentified resistance factors must exist. Here, we describe results of a screen to identify small molecules capable of sensitizing enterococci to broad-spectrum cephalosporins. We found that both Enterococcus faecalis and Enterococcus faecium were sensitized to broad and expanded-spectrum cephalosporins when thymidylate production was impaired, whether by direct inhibition of thymidylate synthase, or by limiting production of cofactors required for its activity. Cephalosporin potentiation is the result of altered exopolysaccharide production due to reduced dTDP-glucose synthesis. Hence, exopolysaccharide production is a previously undescribed contributor to the intrinsic cephalosporin resistance of enterococci and serves as a new target for antienterococcal therapeutics.

  10. Estimation of Enterococci Input from Bathers and Animals on A Recreational Beach Using Camera Images

    PubMed Central

    D, Wang John; M, Solo-Gabriele Helena; M, Abdelzaher Amir; E, Fleming Lora

    2010-01-01

    Enterococci, are used nationwide as a water quality indicator of marine recreational beaches. Prior research has demonstrated that enterococci inputs to the study beach site (located in Miami, FL) are dominated by non-point sources (including humans and animals). We have estimated their respective source functions by developing a counting methodology for individuals to better understand their non-point source load impacts. The method utilizes camera images of the beach taken at regular time intervals to determine the number of people and animal visitors. The developed method translates raw image counts for weekdays and weekend days into daily and monthly visitation rates. Enterococci source functions were computed from the observed number of unique individuals for average days of each month of the year, and from average load contributions for humans and for animals. Results indicate that dogs represent the larger source of enterococci relative to humans and birds. PMID:20381094

  11. Commissioning of the CMS High Level Trigger

    SciTech Connect

    Agostino, Lorenzo; et al.

    2009-08-01

    The CMS experiment will collect data from the proton-proton collisions delivered by the Large Hadron Collider (LHC) at a centre-of-mass energy up to 14 TeV. The CMS trigger system is designed to cope with unprecedented luminosities and LHC bunch-crossing rates up to 40 MHz. The unique CMS trigger architecture only employs two trigger levels. The Level-1 trigger is implemented using custom electronics, while the High Level Trigger (HLT) is based on software algorithms running on a large cluster of commercial processors, the Event Filter Farm. We present the major functionalities of the CMS High Level Trigger system as of the starting of LHC beams operations in September 2008. The validation of the HLT system in the online environment with Monte Carlo simulated data and its commissioning during cosmic rays data taking campaigns are discussed in detail. We conclude with the description of the HLT operations with the first circulating LHC beams before the incident occurred the 19th September 2008.

  12. High Level Waste Disposal System Optimization

    SciTech Connect

    Dirk Gombert; M. Connolly; J. Roach; W. Holtzscheiter

    2005-02-01

    The high level waste (HLW) disposal system consists of the Yucca Mountain Facility (YMF) and waste product (e.g. glass) generation facilities. Responsibility for management is shared between the U. S. Department of Energy (DOE) Offices of Civilian Radioactive Waste Management (DOE-RW) and Environmental Management (DOE-EM). The DOE-RW license application and the Waste Acceptance System Requirements Document (WASRD), as well as the DOE-EM Waste Acceptance Product Specification for Vitrified High Level Waste Forms (WAPS) govern the overall performance of the system. This basis for HLW disposal should be reassessed to consider waste form and process technology research and development (R&D), which have been conducted by DOE-EM, international agencies (i.e. ANSTO, CEA), and the private sector; as well as the technical bases for including additional waste forms in the final license application. This will yield a more optimized HLW disposal system to accelerate HLW disposition, more efficient utilization of the YMF, and overall system cost reduction.

  13. Molecular characterization of vancomycin-resistant enterococci from hospitalized patients and poultry products in The Netherlands.

    PubMed

    van den Braak, N; van Belkum, A; van Keulen, M; Vliegenthart, J; Verbrugh, H A; Endtz, H P

    1998-07-01

    Vancomycin-resistant enterococci (VRE) pose an emerging health risk, but little is known about the precise epidemiology of the genes coding for vancomycin resistance. To determine whether the bacterial flora of consumer poultry serves as a gene reservoir, the level of contamination of poultry products with VRE was determined. VRE were genotyped by pulsed-field gel electrophoresis (PFGE), and transposon structure mapping was done by PCR. The vanX-vanY intergenic regions of several strains were further analyzed by sequencing. A total of 242 of 305 (79%) poultry products were found to be contaminated with VRE. Of these VRE, 142 (59%) were high-level-vancomycin-resistant Enterococcus faecium strains (VREF). PFGE revealed extensive VREF heterogeneity. Two genotypes were found nationwide on multiple occasions: type A (22 of 142 VREF [15%]) and type B (14 of 142 VREF [10%]). No PFGE-deduced genetic overlap was found when VREF from humans were compared with VREF from poultry. Two vanA transposon types were identified among poultry strains. In 59 of 142 (42%) of the poultry VREF, the size of the intergenic region between vanX and vanY was approximately 1,300 bp. This transposon type was not found in human VREF. In contrast, all human strains and 83 of 142 (58%) of the poultry VREF contained an intergenic region 543 bp in size. Sequencing of this 543-bp intergenic vanX-vanY region demonstrated full sequence conservation. Though preliminary, these data suggest that dissemination of the resistance genes carried on transposable elements may be of greater importance than clonal dissemination of resistant strains. This observation is important for developing strategies to control the spread of glycopeptide resistance.

  14. Umbra's High Level Architecture (HLA) Interface

    SciTech Connect

    GOTTLIEB, ERIC JOSEPH; MCDONALD, MICHAEL J.; OPPEL III, FRED J.

    2002-04-01

    This report describes Umbra's High Level Architecture HLA library. This library serves as an interface to the Defense Simulation and Modeling Office's (DMSO) Run Time Infrastructure Next Generation Version 1.3 (RTI NG1.3) software library and enables Umbra-based models to be federated into HLA environments. The Umbra library was built to enable the modeling of robots for military and security system concept evaluation. A first application provides component technologies that ideally fit the US Army JPSD's Joint Virtual Battlespace (JVB) simulation framework for Objective Force concept analysis. In addition to describing the Umbra HLA library, the report describes general issues of integrating Umbra with RTI code and outlines ways of building models to support particular HLA simulation frameworks like the JVB.

  15. The High Level Data Reduction Library

    NASA Astrophysics Data System (ADS)

    Ballester, P.; Gabasch, A.; Jung, Y.; Modigliani, A.; Taylor, J.; Coccato, L.; Freudling, W.; Neeser, M.; Marchetti, E.

    2015-09-01

    The European Southern Observatory (ESO) provides pipelines to reduce data for most of the instruments at its Very Large telescope (VLT). These pipelines are written as part of the development of VLT instruments, and are used both in the ESO's operational environment and by science users who receive VLT data. All the pipelines are highly specific geared toward instruments. However, experience showed that the independently developed pipelines include significant overlap, duplication and slight variations of similar algorithms. In order to reduce the cost of development, verification and maintenance of ESO pipelines, and at the same time improve the scientific quality of pipelines data products, ESO decided to develop a limited set of versatile high-level scientific functions that are to be used in all future pipelines. The routines are provided by the High-level Data Reduction Library (HDRL). To reach this goal, we first compare several candidate algorithms and verify them during a prototype phase using data sets from several instruments. Once the best algorithm and error model have been chosen, we start a design and implementation phase. The coding of HDRL is done in plain C and using the Common Pipeline Library (CPL) functionality. HDRL adopts consistent function naming conventions and a well defined API to minimise future maintenance costs, implements error propagation, uses pixel quality information, employs OpenMP to take advantage of multi-core processors, and is verified with extensive unit and regression tests. This poster describes the status of the project and the lesson learned during the development of reusable code implementing algorithms of high scientific quality.

  16. Distribution and persistence of Escherichia coli and Enterococci in stream bed and bank sediments from two urban streams in Houston, TX.

    PubMed

    Brinkmeyer, Robin; Amon, Rainer M W; Schwarz, John R; Saxton, Tara; Roberts, Dustin; Harrison, Sarah; Ellis, Nicholas; Fox, Jessica; DiGuardi, Katherine; Hochman, Mona; Duan, Shuiwang; Stein, Ron; Elliott, Catherine

    2015-01-01

    The purpose of this research was to determine if Escherichia coli and enterococci in streambed and bank sediments from two urban bayous, Buffalo Bayou and White Oak Bayou, in Houston, TX, USA are a significant source of the chronically high levels of these bacteria in the overlying water. The watersheds of the bayous lie within highly urbanized areas of Greater Houston and there is primary recreational contact with the public. Extensive sampling of the watersheds was conducted from 2008 to 2010. Both fecal indicator bacteria were found at ≥ 10(4)MPNgdry wt.(-1) concentrations in the upper 1cm of sediment cores with declines by orders of magnitude at 15 and 30 cm sediment horizons and in some cases 60 cm, but, nonetheless, indicating that they can remain viable even at depth. No interannual variation was observed. And, there was no correlation with percent organic matter, however there was moderate correlation (R(2)=0.12; p=0.001) of E. coli with sediment moisture. In sediments, most E. coli and enterococci in Buffalo Bayou (76%) and White Oak Bayou (87.5%) were associated with fine sand grains (60 to 250 μm). In the water column, E. coli was associated, in roughly equal percentages, with particle sizes <10, 10-25, 25-63, and ≥ 63 μm (21.9, 25.6, 30.4, and 32.9%, respectively). Enterococci were mostly attached to particle sizes in the ranges of 10-25μm (36.0%) and 25-63 μm (31.1%) as well as ≥ 63 μm (37.7%) (p=0.0001). Fingerprinting of E. coli isolates from both bayous with Rep-PCR and the BOX A1R primer was used to demonstrate translocation of sediments from the upper to lower watersheds.

  17. Proton Affinity Calculations with High Level Methods.

    PubMed

    Kolboe, Stein

    2014-08-12

    Proton affinities, stretching from small reference compounds, up to the methylbenzenes and naphthalene and anthracene, have been calculated with high accuracy computational methods, viz. W1BD, G4, G3B3, CBS-QB3, and M06-2X. Computed and the currently accepted reference proton affinities are generally in excellent accord, but there are deviations. The literature value for propene appears to be 6-7 kJ/mol too high. Reported proton affinities for the methylbenzenes seem 4-5 kJ/mol too high. G4 and G3 computations generally give results in good accord with the high level W1BD. Proton affinity values computed with the CBS-QB3 scheme are too low, and the error increases with increasing molecule size, reaching nearly 10 kJ/mol for the xylenes. The functional M06-2X fails markedly for some of the small reference compounds, in particular, for CO and ketene, but calculates methylbenzene proton affinities with high accuracy.

  18. HIGH LEVEL RF FOR THE SNS RING.

    SciTech Connect

    ZALTSMAN,A.; BLASKIEWICZ,M.; BRENNAN,J.; BRODOWSKI,J.; METH,M.; SPITZ,R.; SEVERINO,F.

    2002-06-03

    A high level RF system (HLRF) consisting of power amplifiers (PA's) and ferrite loaded cavities is being designed and built by Brookhaven National Laboratory (BNL) for the Spallation Neutron Source (SNS) project. It is a fixed frequency, two harmonic system whose main function is to maintain a gap for the kicker rise time. Three cavities running at the fundamental harmonic (h=l) will provide 40 kV and one cavity at the second harmonic (h=2) will provide 20 kV. Each cavity has two gaps with a design voltage of 10 kV per gap and will be driven by a power amplifier (PA) directly adjacent to it. The PA uses a 600kW tetrode to provide the necessary drive current. The anode of the tetrode is magnetically coupled to the downstream cell of the cavity. Drive to the PA will be provided by a wide band, solid state amplifier located remotely. A dynamic tuning scheme will be implemented to help compensate for the effect of beam loading.

  19. Decontamination of high-level waste canisters

    SciTech Connect

    Nesbitt, J.F.; Slate, S.C.; Fetrow, L.K.

    1980-12-01

    This report presents evaluations of several methods for the in-process decontamination of metallic canisters containing any one of a number of solidified high-level waste (HLW) forms. The use of steam-water, steam, abrasive blasting, electropolishing, liquid honing, vibratory finishing and soaking have been tested or evaluated as potential techniques to decontaminate the outer surfaces of HLW canisters. Either these techniques have been tested or available literature has been examined to assess their applicability to the decontamination of HLW canisters. Electropolishing has been found to be the most thorough method to remove radionuclides and other foreign material that may be deposited on or in the outer surface of a canister during any of the HLW processes. Steam or steam-water spraying techniques may be adequate for some applications but fail to remove all contaminated forms that could be present in some of the HLW processes. Liquid honing and abrasive blasting remove contamination and foreign material very quickly and effectively from small areas and components although these blasting techniques tend to disperse the material removed from the cleaned surfaces. Vibratory finishing is very capable of removing the bulk of contamination and foreign matter from a variety of materials. However, special vibratory finishing equipment would have to be designed and adapted for a remote process. Soaking techniques take long periods of time and may not remove all of the smearable contamination. If soaking involves pickling baths that use corrosive agents, these agents may cause erosion of grain boundaries that results in rough surfaces.

  20. Performance of the CMS High Level Trigger

    NASA Astrophysics Data System (ADS)

    Perrotta, Andrea

    2015-12-01

    The CMS experiment has been designed with a 2-level trigger system. The first level is implemented using custom-designed electronics. The second level is the so-called High Level Trigger (HLT), a streamlined version of the CMS offline reconstruction software running on a computer farm. For Run II of the Large Hadron Collider, the increases in center-of-mass energy and luminosity will raise the event rate to a level challenging for the HLT algorithms. The increase in the number of interactions per bunch crossing, on average 25 in 2012, and expected to be around 40 in Run II, will be an additional complication. We present here the expected performance of the main triggers that will be used during the 2015 data taking campaign, paying particular attention to the new approaches that have been developed to cope with the challenges of the new run. This includes improvements in HLT electron and photon reconstruction as well as better performing muon triggers. We will also present the performance of the improved tracking and vertexing algorithms, discussing their impact on the b-tagging performance as well as on the jet and missing energy reconstruction.

  1. DEFENSE HIGH LEVEL WASTE GLASS DEGRADATION

    SciTech Connect

    W. Ebert

    2001-09-20

    The purpose of this Analysis/Model Report (AMR) is to document the analyses that were done to develop models for radionuclide release from high-level waste (HLW) glass dissolution that can be integrated into performance assessment (PA) calculations conducted to support site recommendation and license application for the Yucca Mountain site. This report was developed in accordance with the ''Technical Work Plan for Waste Form Degradation Process Model Report for SR'' (CRWMS M&O 2000a). It specifically addresses the item, ''Defense High Level Waste Glass Degradation'', of the product technical work plan. The AP-3.15Q Attachment 1 screening criteria determines the importance for its intended use of the HLW glass model derived herein to be in the category ''Other Factors for the Postclosure Safety Case-Waste Form Performance'', and thus indicates that this factor does not contribute significantly to the postclosure safety strategy. Because the release of radionuclides from the glass will depend on the prior dissolution of the glass, the dissolution rate of the glass imposes an upper bound on the radionuclide release rate. The approach taken to provide a bound for the radionuclide release is to develop models that can be used to calculate the dissolution rate of waste glass when contacted by water in the disposal site. The release rate of a particular radionuclide can then be calculated by multiplying the glass dissolution rate by the mass fraction of that radionuclide in the glass and by the surface area of glass contacted by water. The scope includes consideration of the three modes by which water may contact waste glass in the disposal system: contact by humid air, dripping water, and immersion. The models for glass dissolution under these contact modes are all based on the rate expression for aqueous dissolution of borosilicate glasses. The mechanism and rate expression for aqueous dissolution are adequately understood; the analyses in this AMR were conducted to

  2. Biofilm Formation by Drug Resistant Enterococci Isolates Obtained from Chronic Periodontitis Patients

    PubMed Central

    Mehta, Manjula; Sood, Shaveta; Sharma, Jyoti

    2017-01-01

    Introduction Enterococci are an important cause of opportunistic nosocomial infections and several multidrug resistant strains have emerged. The severity of periodontal diseases is managed by reduction in the pathogenic bacteria. There is a need to assess the prevalence and antibiotic susceptibility of enterococci colonizing the periodontal pocket and correlate its biofilm formation ability because oral biofilms provide a protective environment and are a reservoir of bacterial colonization of the gingival crevice. Aim To investigate possible association between antibiotic susceptibility and biofilm formation in enterococci isolates from chronic periodontitis patients. Materials and Methods This retrospective study was conducted at Dr. Harvansh Singh Judge Institute of Dental Sciences and Hospital, Punjab University, Chandigarh from January 2015 to October 2015. Sterile paper points were inserted in the periodontal pocket of 100 subjects and put in a transport media. Forty -six isolates were identified as enterococci. The isolates were further examined for their ability to form biofilm by microtitre plate assay and antimicrobial susceptibility testing was done by disc diffusion method for clinically relevant antibiotics. Results Significant relationship (p<0.001) was found between biofilm production with antibiotic resistance to Vancomycin, Erythromycin, Ciprofloxacin, Tiecoplanin, Amoxycillin and Gentamycin. Conclusion The study demonstrates a high propensity among the isolates of Enterococci to form biofilm and a significant association of biofilm with multiple drug resistance. PMID:28273964

  3. Biofilm Formation, gel and esp Gene Carriage among Recreational Beach Enterococci

    PubMed Central

    Asmat, Ahmad; Dada, Ayokunle Christopher; Gires, Usup

    2014-01-01

    Biofilm production, gel and esp gene carriage was enumerated among forty six vancomycin resistant enterococci (VRE) and vancomycin susceptible enterococci (VSE) beach isolates. A higher proportion (61.54%) of biofilm producers was observed among beach sand as compared to beach water enterococci isolates (30%) indicating that enterococci within the sand column may be more dependent on biofilm production for survival than their beach water counterparts. Correlation analysis revealed strongly negative correlation (r=-0.535, p=0.015) between vancomycin resistance and biofilm formation. Given the observation of high prevalence of biofilm production among beach sand and the concomitant absence of esp gene carriage in any of the isolate, esp gene carriage may not be necessary for the production of biofilms among beach sand isolates. On the whole beach sand and water isolates demonstrated clearly different prevalence levels of vancomycin resistance, biofilm formation, esp and gel gene carriage. Application of these differences may be found useful in beach microbial source tracking studies. Tested starved cells still produced biofilm albeit at lower efficiencies. Non-dividing enterococci in beach sand can survive extended periods of environmental hardship and can resume growth or biofilm production in appropriate conditions thus making them infectious agents with potential health risk to recreational beach users. PMID:25168975

  4. Biofilm formation, gel and esp gene carriage among recreational beach Enterococci.

    PubMed

    Asmat, Ahmad; Dada, Ayokunle Christopher; Gires, Usup

    2014-06-12

    Biofilm production, gel and esp gene carriage was enumerated among forty six vancomycin resistant enterococci (VRE) and vancomycin susceptible enterococci (VSE) beach isolates. A higher proportion (61.54%) of biofilm producers was observed among beach sand as compared to beach water enterococci isolates (30%) indicating that enterococci within the sand column may be more dependent on biofilm production for survival than their beach water counterparts. Correlation analysis revealed strongly negative correlation (r=-0.535, p=0.015) between vancomycin resistance and biofilm formation. Given the observation of high prevalence of biofilm production among beach sand and the concomitant absence of esp gene carriage in any of the isolate, esp gene carriage may not be necessary for the production of biofilms among beach sand isolates. On the whole beach sand and water isolates demonstrated clearly different prevalence levels of vancomycin resistance, biofilm formation, esp and gel gene carriage. Application of these differences may be found useful in beach microbial source tracking studies. Tested starved cells still produced biofilm albeit at lower efficiencies. Non-dividing enterococci in beach sand can survive extended periods of environmental hardship and can resume growth or biofilm production in appropriate conditions thus making them infectious agents with potential health risk to recreational beach users.

  5. A critical evaluation of a flow cytometer used for detecting enterococci in recreational waters.

    PubMed

    King, Dawn N; Brenner, Kristen P; Rodgers, Mark R

    2007-06-01

    The current U. S. Environmental Protection Agency-approved method for enterococci (Method 1600) in recreational water is a membrane filter (MF) method that takes 24 hours to obtain results. If the recreational water is not in compliance with the standard, the risk of exposure to enteric pathogens may occur before the water is identified as hazardous. Because flow cytometry combined with specific fluorescent antibodies has the potential to be used as a rapid detection method for microorganisms, this technology was evaluated as a rapid, same-day method to detect enterococci in bathing beach waters. The flow cytometer chosen for this study was a laser microbial detection system designed to detect labeled antibodies. A comparison of MF counts with flow cytometry counts of enterococci in phosphate buffer and sterile-filtered recreational water showed good agreement between the two methods. However, when flow cytometry was used, the counts were several orders of magnitude higher than the MF counts with no correlation to Enterococcus spike concentrations. The unspiked sample controls frequently had higher counts than the samples spiked with enterococci. Particles within the spiked water samples were probably counted as target cells by the flow cytometer because of autofluorescence or non-specific adsorption of antibody and carryover to subsequent samples. For these reasons, this technology may not be suitable for enterococci detection in recreational waters. Improvements in research and instrument design that will eliminate high background and carryover may make this a viable technology in the

  6. Occurrence, genetic diversity, and persistence of enterococci in a Lake Superior watershed.

    PubMed

    Ran, Qinghong; Badgley, Brian D; Dillon, Nicholas; Dunny, Gary M; Sadowsky, Michael J

    2013-05-01

    In 2012, the U.S. EPA suggested that coastal and Great Lakes states adopt enterococci as an alternative indicator for the monitoring of recreational water quality. Limited information, however, is available about the presence and persistence of enterococci in Lake Superior. In this study, the density, species composition, and persistence of enterococci in sand, sediment, water, and soil samples were examined at two sites in a Lake Superior watershed from May to September over a 2-year period. The genetic diversity of Enterococcus faecalis isolates collected from environmental samples was also studied by using the horizontal, fluorophore-enhanced repetitive PCR DNA fingerprinting technique. Results obtained by most-probable-number analyses indicated that enterococci were present in 149 (94%) of 159 samples and their densities were generally higher in the summer than in the other months examined. The Enterococcus species composition displayed spatial and temporal changes, with the dominant species being E. hirae, E. faecalis, E. faecium, E. mundtii, and E. casseliflavus. DNA fingerprint analyses indicated that the E. faecalis population in the watershed was genetically diverse and changed spatially and temporally. Moreover, some DNA fingerprints reoccurred over multiple sampling events. Taken together, these results suggest that some enterococci are able to persist and grow in the Lake Superior watershed, especially in soil, for a prolonged time after being introduced.

  7. Detection of vancomycin resistances in enterococci within 3 1/2 hours

    NASA Astrophysics Data System (ADS)

    Schröder, U. -Ch.; Beleites, C.; Assmann, C.; Glaser, U.; Hübner, U.; Pfister, W.; Fritzsche, W.; Popp, J.; Neugebauer, U.

    2015-02-01

    Vancomycin resistant enterococci (VRE) constitute a challenging problem in health care institutions worldwide. Novel methods to rapidly identify resistances are highly required to ensure an early start of tailored therapy and to prevent further spread of the bacteria. Here, a spectroscopy-based rapid test is presented that reveals resistances of enterococci towards vancomycin within 3.5 hours. Without any specific knowledge on the strain, VRE can be recognized with high accuracy in two different enterococci species. By means of dielectrophoresis, bacteria are directly captured from dilute suspensions, making sample preparation very easy. Raman spectroscopic analysis of the trapped bacteria over a time span of two hours in absence and presence of antibiotics reveals characteristic differences in the molecular response of sensitive as well as resistant Enterococcus faecalis and Enterococcus faecium. Furthermore, the spectroscopic fingerprints provide an indication on the mechanisms of induced resistance in VRE.

  8. Application of multiplex PCR, pulsed-field gel electrophoresis (PFGE), and BOX-PCR for molecular analysis of enterococci

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of the study was to use band-based molecular methods including BOX-PCR (Polymerase Chain Reaction) and Pulsed-Field Gel Electrophoresis (PFGE) to determine if genetically related enterococci were found among different stores, food types, or years. Enterococci were also characterized f...

  9. Use of a methylene blue azide medium for isolation of enterococci.

    PubMed

    Smith, R F; Bodily, H L

    1967-09-01

    A methylene blue azide medium (MBA), developed by Schaedler, Dubos, and Costello to isolate enterococci from the gastrointestinal tract of animals, was evaluated. This was done by comparing the isolation of enterococci from feces and saliva on the medium. Fifty-two catalase-negative, gram-positive cocci from human feces isolated from MBA were classified as enterococci. All strains grew in S F, 6.5% NaCl, and streptomycin broths, and all fermented mannitol. The isolates were provisionally subdivided into Streptococcus faecalis and S. faecium groups. S. faecalis-like strains fermented glycerol and pyruvate aerobically and produced acid in Snyder's medium (initial pH, 4.8). The S. faecium group fermented raffinose. Among all strains, several tests were variable. These included growth at 45 C, in 0.1% tellurite and in methylene blue milk. Three methods were employed to isolate and identify enterococci from the oral cavity. Direct streaking of MBA with saliva failed to produce any growth on the medium. Two other methods, with the use of various selective broths to promote the recovery of oral enterococci, failed to produce any bacteria capable of growing on MBA. The MBA-isolated fecal strains and oral viridans streptococci were generally indistinguishable on Mitis-Salivarius and K F agars. In experiments with fecal material, no gram-negative bacilli were found among the isolates selected. The MBA medium was judged as a high selectivity-low yield medium, and may provide a means of separating fecal and nonfecal enterococci.

  10. Generation of enterococci bacteria in a coastal saltwater marsh and its impact on surf zone water quality.

    PubMed

    Grant, S B; Sanders, B F; Boehm, A B; Redman, J A; Kim, J H; Mrse, R D; Chu, A K; Gouldin, M; McGee, C D; Gardiner, N A; Jones, B H; Svejkovsky, J; Leipzig, G V; Brown, A

    2001-06-15

    Elevated levels of enterococci bacteria, an indicator of fecal pollution, are routinely detected in the surf zone at Huntington State and City Beaches in southern California. A multidisciplinary study was carried out to identify sources of enterococci bacteria landward of the coastline. We find that enterococci bacteria are present at high concentrations in urban runoff, bird feces, marsh sediments, and on marine vegetation. Surprisingly, urban runoff appears to have relatively little impact on surf zone water quality because of the long time required for this water to travel from its source to the ocean. On the other hand, enterococci bacteria generated in a tidal saltwater marsh located near the beach significantly impact surf zone water quality. This study identifies a potential tradeoff between restoring coastal wetlands and protecting beach water quality and calls into question the use of ocean bathing water standards based on enterococci at locations near coastal wetlands.

  11. Gastrointestinal Colonization with Vancomycin-Resistant Enterococci In Hospitalized and Outpatients

    PubMed Central

    Trajkovska-Dokic, Elena; Kaftandzieva, Ana; Stojkovska, Snezana; Kuzmanovska, Aneta; Panovski, Nikola

    2015-01-01

    BACKGROUND: The incidence of infection and intestinal colonization with vancomycin resistant enterococci (VRE) is increasing in many countries in the last decade. Concerning the difficult antimicrobial treatment of infections caused by VRE, decreasing the incidence and prevalence of these infections is an important factor in VRE-induced morbidity and mortality control. AIM: To determine the prevalence of gastrointestinal colonization with vancomycin resistant enterococci in hospitalized and outpatients, and to determine the genetic base of the vancomycin resistance in VRE isolates. MATERIAL AND METHODS: Seven hundred and eighty stool specimens were investigated for the gastrointestinal carriage of vancomycin-resistant enterococci (VRE). Susceptibility to vancomycin was tested in all isolates by disk-diffusion test and E-test (AB Biodisk, Sweden). Determined vancomycin resistant enterococci were than tested for detection of vanA, vanB and vanC genes by PCR. RESULTS: Vancomycin resistant strains of enterococci were isolated from 46 (16.1 %) of the 285 hospitalized patients and 5 (7.7 %) of the 65 patients living in the community (p < 0.05). The most of the highly resistant enterococci strains to vancomycin (95.2 %), were identified as E. faecium. Minimal inhibitory concentrations (MICs) to vancomycin in all 39 vanA genotypes of E. faecium and two vanA genotypes of E. fecalis were > 256 μg/ml. Three vanB genotypes of E. faecium and one vanB genotype of E. faecalis had MICs of 32 μg/ml. All six vanC genotypes of E. gallinarum had MICs of 8 μg/ml. All vanA genotypes of VRE were highly resistant to vancomycin, with MICs above 256 μg/ml. Three vanB genotypes of VR E. faecium and one VR E. fecalis were resistant, with MICs 32 μg/ml. vanC genotypes of VR E. gallinarum were intermediate resistant to vancomycin with MICs of 8 μg/ml. CONCLUSIONS: The prevalence of vancomycin resistant enterococci in Republic of Macedonia was 2-fold higher in hospitalized than in

  12. Coliforms, Enterococci, Thermodurics, Thermophiles, and Psychrophiles in Untreated Farm Pond Waters

    PubMed Central

    Malaney, G. W.; Weiser, H. H.; Turner, R. O.; Van Horn, Marilyn

    1962-01-01

    Untreated waters from ten farm ponds located in central, north central, southeastern, and southwestern Ohio were examined for numbers of coliforms, enterococci, thermodurics, thermophiles, and psychrophiles. The median population densities per 100 ml water for all ponds were: coliforms, 23; enterococci, 3.6; thermodurics, 6,000; thermophiles, 450; psychrophiles, 1,000. The results indicate that these farm pond waters were only lightly polluted and suggest that farm ponds, properly maintained, are a source of raw water of high bacteriological quality, requiring a minimum of treatment to be made suitable for domestic and livestock purposes. PMID:14468809

  13. Escherichia coli and enterococci at beaches in the Grand Traverse Bay, Lake Michigan: Sources, characteristics, and environmental pathways

    USGS Publications Warehouse

    Haack, S.K.; Fogarty, L.R.; Wright, C.

    2003-01-01

    This study quantified Escherichia coli(EC) and enterococci (ENT) in beach waters and dominant source materials, correlated these with ambient conditions, and determined selected EC genotypes and ENT phenotypes. Bathing-water ENT criteria were exceeded more frequently than EC criteria, providing conflicting interpretations of water quality. Dominant sources of EC and ENT were bird feces (108/d/bird), storm drains (107/d), and river water (1011/d); beach sands, shallow groundwater and detritus were additional sources. Beach-water EC genotypes and ENT phenotypes formed clusters with those from all source types, reflecting diffuse inputs. Some ENT isolates had phenotypes similar to those of human pathogens and/or exhibited high-level resistance to human-use antibiotics. EC and ENT concentrations were influenced by collection time and wind direction. There was a 48-72-h lag between rainfall and elevated EC concentrations at three southern shoreline beaches, but no such lag at western and eastern shoreline beaches, reflecting the influence of beach orientation with respect to cyclic (3-5 d) summer weather patterns. In addition to local contamination sources and processes, conceptual or predictive models of Great Lakes beach water quality should consider regional weather patterns, lake hydrodynamics, and the influence of monitoring method variables (time of day, frequency).

  14. Prevalence and Molecular Epidemiology of Vancomycin-Resistant Enterococci (VRE) Strains Isolated from Animals and Humans in Korea

    PubMed Central

    Song, Joon Young; Hwang, In Sook; Eom, Joong Sik; Cheong, Hee Jin; Bae, Won Ki; Park, Yong Ho

    2005-01-01

    Background To assess the possibility of VRE transmission from animals to humans, we studied the prevalence of vancomycin-resistant enterococci (VRE) in farm animals, raw chicken meat, and healthy people. We then determined the molecular relatedness of VRE isolates between animals and humans in Korea. Methods We aimed to isolate VRE from 150 enterococci specimens of farm animals, 15 raw chicken meat samples, and stools from 200 healthy people. Species differentiation was done with conventional biochemical tests. Vancomycin resistance genotyping was done by polymerase chain reaction (PCR). Using the agar dilution method, antimicrobial susceptibility was tested for 8 antimicrobials and pulsed-field gel electrophoresis (PFGE) was done to evaluate the molecular relatedness of VRE isolates. Results The prevalence of VRE was 14.7% (22/150) in farm animal specimens, 1% (2/200) in healthy people, and 60% (9/15) in raw chicken meat. Of 22 animal VRE isolates, 1 vanA E. faecium, 15 vanC1 E. gallinarum, and 6 vanC2 E. casseliflavus were identified. All of the 9 VRE from raw chicken meat and all of the 20 clinical VRE strains were vanA E. faecium. However, in healthy people, only 2 vanC2 E. casseliflavus were isolated. These showed low-level resistance to vancomycin and susceptibility to teicoplanin. However, 9 VRE strains from raw chicken meat had high-level resistance to vancomycin (MIC50,90: >128 µg/mL), teicoplanin (MIC50,90: >128 µg/mL), ampicillin (MIC50,90: >128 µg/mL), erythromycin (MIC50,90: >128 µg/mL), and tetracycline (MIC50,90: 128/>128 µg/mL). Conclusion This study demonstrated little evidence of VRE colonization in healthy people despite high recovery of VRE among raw chicken meat. It is suggested that there is little evidence of VRE transmission from animals to healthy people. However, we assumed that there exists the possibility of VRE contamination during the processing of chicken meat. PMID:15906954

  15. Immunochemical characterization of polysaccharide antigens from six clinical strains of Enterococci

    PubMed Central

    Hsu, Carolyn T; Ganong, Amanda L; Reinap, Barbara; Mourelatos, Zafiria; Huebner, Johannes; Wang, Julia Y

    2006-01-01

    Background Enterococci have become major nosocomial pathogens due to their intrinsic and acquired resistance to a broad spectrum of antibiotics. Their increasing drug resistance prompts us to search for prominent antigens to develop vaccines against enterococci. Given the success of polysaccharide-based vaccines against various bacterial pathogens, we isolated and characterized the immunochemical properties of polysaccharide antigens from five strains of Enterococcus faecalis and one strain of vancomycin-resistant E. faecium. Results We cultured large batches of each strain, isolated sufficient quantities of polysaccharides, analyzed their chemical structures, and compared their antigenic specificity. Three classes of polysaccharides were isolated from each strain, including a polyglucan, a teichoic acid, and a heteroglycan composed of rhamnose, glucose, galactose, mannosamine, and glucosamine. The polyglucans from all six strains are identical and appear to be dextran. Yields of the teichoic acids were generally low. The most abundant polysaccharides are the heteroglycans. The six heteroglycans are structurally different as evidenced by NMR spectroscopy. They also differ in their antigenic specificities as revealed by competitive ELISA. The heteroglycans are not immunogenic by themselves but conjugation to protein carriers significantly enhanced their ability to induce antibodies. Conclusion The six clinical strains of enterococci express abundant, strain-specific cell-surface heteroglycans. These polysaccharides may provide a molecular basis for serological typing of enterococcal strains and antigens for the development of vaccines against multi-drug resistant enterococci. PMID:16836754

  16. Efficient Inactivation of Multi-Antibiotics Resistant Nosocomial Enterococci by Purified Hiracin Bacteriocin

    PubMed Central

    Hassan, Maryam; Brede, Dag Anders; Diep, Dzung B.; Nes, Ingolf F.; Lotfipour, Farzaneh; Hojabri, Zoya

    2015-01-01

    Purpose: Because of the emergence of multi-antibiotic resistant bacteria, a number of infectious diseases have become a major concern to treat in health care services worldwide. This situation is worsened by the fact that very limited progress has been made in developing new and potent antibiotics in recent years. In this context antimicrobial peptides (AMPs) represent new potential therapeutic compounds with bactericidal or bacteriostatic activity against closely related bacterial strains. Methods: In this study, a collection of enterococci (n=170) from clinical sources were investigated for their potential to inhibit multiresistant nosocomial enterococci from Iranian hospitals. Results: Four isolates produced antimicrobial peptides that inhibited all the antibiotic resistant enterococci. This included three Enterococcus faecium isolates producing combinations of enterocin A, B and L50 AB. The most potent antagonism was produced by E. faecalis HO91. Purification and subsequent characterization by MALDI-TOF MS, Edman degradation and DNA-sequencing revealed that the antimicrobial compound was Hiracin. The purified Hiracin was evaluated for antibacterial activity against 12 multiresistant enterococcal isolates from clinical samples. The results demonstrated that Hiracin is highly effective towards enterococci which were resistant even to antibiotics from four distinct classes. Conclusion: The present research addresses Hiracin as a promising alternative to conventional antibiotics in treatment of multiresistant enterococcal infections. PMID:26504762

  17. Comparison of several laboratory media for presumptive identification of enterococci and group D streptococci.

    PubMed

    Facklam, R R

    1973-08-01

    Bile-esculin (Difco), modified bile-esculin (Difco), selective enterococcus (Pfizer Co.), and eosin-methylene blue agar media were evaluated for accuracy in identifying group D streptococci. The regular and modified bile-esculin media performed equally well, but the selective enterococcus and eosin-methylene blue agars did not accurately differentiate the group D from non-group D streptococci. A modified 6.5% NaCl broth was compared with unmodified 6.5% NaCl broth and Streptococcus faecalis (SF; Difco) broth for accuracy in differentiating enterococci from non-enterococci. The modified and unmodified broths worked equally well in the salt tolerance test, but the lot-to-lot variability of SF broth made this medium unusable as an indicator for enterococci. With all seven media, the number of strains giving positive tests decreased when the tests were incubated at 45 C as compared with 35 C, and the number of strains giving negative tests increased. Thus, the number of false-positive identifications decreased, but the number of false-negative identifications increased. Variability in the susceptibility of group D non-enterococcal streptococci to oxacillin and methicillin sensitivity disks limited the usefulness of these tests for presumptive identification of either enterococci or group D streptococci.

  18. Comparison of enterococci and coliform microorganisms in commercially produced pecan nut meats.

    PubMed

    HYNDMAN, J B

    1963-05-01

    Pecan nut meats in the unbroken shell are sterile for enteric microorganisms. Recovery of coliform microorganisms or enterococci from finished pecan nut meats indicated contact contamination, assuming the tempering procedures to be satisfactory. Results of specific studies, designed toward developing background data on the sanitary significance of enterococci and coliform microorganisms in the production of pecan meats are reported. Unbroken pecan nuts or nut meats from various stages of shelling operations were diluted with a phosphate-buffered diluent. Serial dilutions were inoculated into Lactose Broth and Azide Dextrose Broth. The lactose fermentors were carried through indole, methyl red, Voges-Proskauer, and citrate reactions; the positive Azide Dextrose cultures were confirmed in Ethyl Violet Azide Broth and microscopically. Viable plate counts were obtained. Enterococci were found resistant to many deterrent factors affecting coliforms. Recoveries of enterococci were detected long after pollution had occurred. Little correlation was found between enterococcal recovery and observed insanitary practices in commercial shelling operations. Using the coliaerogenes group and, specifically, Escherichia coli as a sanitation index, microorganisms allowed accurate appraisal of tempering, personnel practices, and contact surface contaminating factors. It is felt this was due, in part, to the more delicate growth characteristics of E. coli. The fact that other pathogenic microorganisms, capable of causing gastrointestinal upsets, are associated with the presence of E. coli introduces a health factor which is important to regulatory agencies concerned with consumer protection.

  19. Evaluation of thallium acetate-citrate medium for isolation of enterococci.

    PubMed

    Bulich, A A; Hartman, P A

    1969-11-01

    Thallous acetate-citrate (TAC) agar, a selective medium for isolating enterococci from frozen foods, was evaluated. Two types of bacteria, micrococci and group N streptococci, were responsible for erroneously high enterococcus counts on TAC agar. Selectivity of the medium was improved by the addition of 0.01% sodium azide.

  20. Genome sequencing reveals the environmental origin of enterococci and potential biomarkers for water quality monitoring.

    PubMed

    Weigand, Michael R; Ashbolt, Nicholas J; Konstantinidis, Konstantinos T; Santo Domingo, Jorge W

    2014-04-01

    Enterococci are common members of the gut microbiome and their ease of culturing has facilitated worldwide use as indicators of fecal pollution of waters. However, enterococci were recently shown to persist in environmental habitats, often in the absence of fecal input, potentially confounding water quality assays. Toward resolving this issue and providing a more complete picture of natural enterococci diversity, 11 isolates of Enterococcus faecalis recovered from freshwater watersheds (environmental) were sequenced and compared to 59 available enteric genomes. Phenotypically and phylogenetically the environmental E. faecalis were indistinguishable from their enteric counterparts. However, distinct environmental- and enteric-associated gene signatures, encoding mostly accessory nutrient utilization pathways, were detected among the variable genes. Specifically, a nickel uptake operon was over-represented in environmental genomes, while genes for utilization of sugars thought to be abundant in the gut such as xylose were over-represented in enteric genomes. The distribution and phylogeny of these identified signatures suggest that ancestors of E. faecalis resided in extra-enteric habitats, challenging the prevailing commensal view of enterococci ecology. Thus, habitat-associated gene content changes faster than core genome phylogeny and may include biomarkers for reliably detecting fecal contaminants for improved microbial water quality monitoring.

  1. Effect of growth promotant usage on enterococci species on a poultry farm.

    PubMed

    Debnam, Antoinette L; Jackson, Charlene R; Avellaneda, Gloria E; Barrett, John B; Hofacre, Charles L

    2005-09-01

    The species population of enterococci isolated from four poultry houses for six grow-outs on one farm was determined. Two houses on the farm were control houses and did not use any antimicrobials, while two other houses on the farm used flavomycin, virginiamycin, and bacitracin during different poultry grow-outs. Litter, chick boxliners, feed, and poultry carcass rinses were obtained from each house and cultured for the presence of enterococci. Nine species of enterococci (Enterococcusfaecalis, E. faecium, E. avium, E. casselifiavus, E. cecorum, E. durans, E. gallinarum, E. hirae, and E. malodoratus) were identified from the study. Enterococcus faecalis was isolated more frequently from chick boxliners (n=176; 92%) and carcass rinses (n=491; 69%), whereas E. faecium was found more frequently in litter (n=361; 77%) and feed (n=67; 64%). Enterococcus faecalis (n=763; 52%) and E. faecium (n=578; 39%) were isolated most often from the farm and houses, regardless of antimicrobial treatment. Fifty-two percent of E. faecalis and 39% of E. faecium were isolated from both control (n=389 and 295, respectively) and treatment (n=374 and 283, respectively) samples. This study indicates that antimicrobial usage on this farm did not alter the resident population of enterococci.

  2. Evaluation of photoreactivation of Escherichia coli and Enterococci after UV disinfection of municipal wastewater.

    PubMed

    Locas, Annie; Demers, Josée; Payment, Pierre

    2008-11-01

    Because chlorine disinfection is not permitted in the province of Quebec, wastewater disinfection by ultraviolet (UV) light has been used for years in wastewater treatment plants. Thermotolerant coliforms discharge criteria are set for each plant and are adjusted by a factor of 1 log to compensate for photoreactivation in UV-disinfected effluents. The current study evaluated levels of Escherichia coli and enterococci photoreactivation from disinfected wastewater under varying temperature, visible light, and type of UV lamps. Escherichia coli photoreactivation increased significantly after exposure to 5600 lx compared with 1600 lx of visible light. This increase was significantly higher in warm water (25 degrees C) than cold water (4 degrees C). The level of photoreactivation of E. coli was also higher after wastewater disinfection by low-pressure UV lamps as opposed to medium-pressure UV lamps. Enterococci, however, were not photoreactivated under any test conditions. This result suggests that enterococci could be a better indicator than thermotolerant coliforms or E. coli. The use of enterococci would also eliminate the requirement to set different discharge criteria based on disinfection type (UV or chemical) and would also provide a better assessment of treatment efficiency for more resistant microorganisms.

  3. Application of a plasmid classification system to determine prevalence of replicon families among multidrug resistant enterococci

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence and transfer of plasmids from commensal bacteria to more pathogenic bacteria may contribute to dissemination of antimicrobial resistance. However, prevalence of plasmids from commensal bacteria in food animals such as the enterococci remains largely unknown. In this study, the prevale...

  4. A CRITICAL EVALUATION OF A FLOW CYTOMETER USED FOR DETECTING ENTEROCOCCI IN RECREATIONAL WATERS

    EPA Science Inventory

    The current U. S. Environmental Protection Agency-approved method for enterococci (Method 1600) in recreational water is a membrane filter (MF) method that takes 24 hours to obtain results. If the recreational water is not in compliance with the standard, the risk of exposure to...

  5. Effect of Environmental Parameters on the qPCR Signal of Enterococci in Tropical Waters

    EPA Science Inventory

    Fecal contamination is the major source of pathogens in recreational waters. The need for quick public notifications has expanded the interest in the use of a rapid, quantitative polymerase chain reaction method (qPCR) to determine enterococci density. However, very little info...

  6. Development of a caseinase assay for PCR independent detection of esp gene carriage among enterococci

    NASA Astrophysics Data System (ADS)

    Dada, Ayokunle Christopher; Asmat, Ahmad; Lee, Yook Heng; Usup, Gires

    2013-11-01

    Currently, there is no known relationship between caseinase and carriage of esp gene. Also, no breakpoints exist for phenotypic assays that are used to infer virulence characteristics among Enterococci. In the present study, caseinase activity was measured by a radial diffusion assay for 113 enterococci isolates. A standard curve with predictive r2 value of 0.939 was produced by dispensing several doubling dilutions of proteinase K into 3% skimmed milk agar wells. Caseinase activity for all tested enterococci was subsequently converted into proteinase K activity, using the obtained chart. Caseinase activity ranged from 1.74 × 10-8 to 4.47 × 10-7ug/ml and 6.37 × 10-8 to 8.82 × 10-8 ug/ml per colony of environmental and clinical enterocococci tested, proportionate to proteinase K activity. Caseinase activity among environmental strains was five-fold higher than was observed among clinical strains. Fishers exact test revealed significant associations between esp gene carriage and caseinase activity (diameter on skimmed milk, z=8 to 13mm) at p<0.1. However, the probability of association was strongest at z=13 mm (p=0.033) suggesting a range of diameter cut-offs that was exclusive to and may be used to predict the presence of environmental enterococci strains harbouring esp gene. Results obtained from sensitivity analysis showed increasing assay sensitivity from cut-off of 9 mm (61.54%) up to 84.62% (13 mm). Specificity of the caseinase assay slightly decreased from 50% to 42.86% as cut-off increased from 9 to 13 mm. The caseinase assay described here potentially proves useful in preliminary PCR independent screening of environmental enterococci isolates for the detection of strains which carry the esp gene known to increase the severity of enterococcal infections.

  7. High-Level Vancomycin-Resistant Staphylococcus aureus Isolates Associated with a Polymicrobial Biofilm▿

    PubMed Central

    Weigel, Linda M.; Donlan, Rodney M.; Shin, Dong Hyeon; Jensen, Bette; Clark, Nancye C.; McDougal, Linda K.; Zhu, Wenming; Musser, Kimberlee A.; Thompson, Jill; Kohlerschmidt, Donna; Dumas, Nellie; Limberger, Ronald J.; Patel, Jean B.

    2007-01-01

    Glycopeptides such as vancomycin are the treatment of choice for infections due to methicillin-resistant Staphylococcus aureus. This study describes the identification of high-level vancomycin-resistant S. aureus (VRSA) isolates in a polymicrobial biofilm within an indwelling nephrostomy tube in a patient in New York. S. aureus, Enterococcus faecalis, Enterococcus faecium, Micrococcus species, Morganella morganii, and Pseudomonas aeruginosa were isolated from the biofilm. For VRSA isolates, vancomycin MICs ranged from 32 to >128 μg/ml. VRSA isolates were also resistant to aminoglycosides, fluoroquinolones, macrolides, penicillin, and tetracycline but remained susceptible to chloramphenicol, linezolid, rifampin, and trimethoprim-sulfamethoxazole. The vanA gene was localized to a plasmid of ∼100 kb in VRSA and E. faecium isolates from the biofilm. Plasmid analysis revealed that the VRSA isolate acquired the 100-kb E. faecium plasmid, which was then maintained without integration into the MRSA plasmid. The tetracycline resistance genes tet(U) and tet(S), not previously detected in S. aureus isolates, were identified in the VRSA isolates. Additional resistance elements in the VRSA isolate included a multiresistance gene cluster, ermB-aadE-sat4-aphA-3, msrA (macrolide efflux), and the bifunctional aminoglycoside resistance gene aac(6′)-aph(2")-Ia. Multiple combinations of resistance genes among the various isolates of staphylococci and enterococci, including vanA, tet(S), and tet(U), illustrate the dynamic nature of gene acquisition and loss within and between bacterial species throughout the course of infection. The potential for interspecies transfer of antimicrobial resistance genes, including resistance to vancomycin, may be enhanced by the microenvironment of a biofilm. PMID:17074796

  8. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false High-level radioactive waste. 227.30...-level radioactive waste. High-level radioactive waste means the aqueous waste resulting from the operation of the first cycle solvent extraction system, or equivalent, and the concentrated waste...

  9. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false High-level radioactive waste. 227.30...-level radioactive waste. High-level radioactive waste means the aqueous waste resulting from the operation of the first cycle solvent extraction system, or equivalent, and the concentrated waste...

  10. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true High-level radioactive waste. 227.30...-level radioactive waste. High-level radioactive waste means the aqueous waste resulting from the operation of the first cycle solvent extraction system, or equivalent, and the concentrated waste...

  11. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false High-level radioactive waste. 227.30...-level radioactive waste. High-level radioactive waste means the aqueous waste resulting from the operation of the first cycle solvent extraction system, or equivalent, and the concentrated waste...

  12. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false High-level radioactive waste. 227.30...-level radioactive waste. High-level radioactive waste means the aqueous waste resulting from the operation of the first cycle solvent extraction system, or equivalent, and the concentrated waste...

  13. Process for solidifying high-level nuclear waste

    DOEpatents

    Ross, Wayne A.

    1978-01-01

    The addition of a small amount of reducing agent to a mixture of a high-level radioactive waste calcine and glass frit before the mixture is melted will produce a more homogeneous glass which is leach-resistant and suitable for long-term storage of high-level radioactive waste products.

  14. 46 CFR 119.530 - Bilge high level alarms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Bilge high level alarms. 119.530 Section 119.530... Bilge and Ballast Systems § 119.530 Bilge high level alarms. (a) Each vessel must be provided with a visual and audible alarm at the operating station to indicate a high water level in each of the...

  15. 46 CFR 182.530 - Bilge high level alarms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Bilge high level alarms. 182.530 Section 182.530... TONS) MACHINERY INSTALLATION Bilge and Ballast Systems § 182.530 Bilge high level alarms. (a) On a... operating station to indicate a high water level in each of the following normally unmanned spaces: (1)...

  16. Potential use of presumptive enterococci and staphylococci as indicators of sanitary condition in plants making hard Italian-type cheese.

    PubMed

    Ingham, S C; Reyes, J C; Schoeller, N P; Lang, M M

    2000-12-01

    Raw milk, pasteurized milk, unripened cheese (1 day old), and partially ripened cheese (3 months) from 42 milk lots at a plant making hard Italian-type cheese were analyzed for presumptive enterococci using kanamycin esculin azide agar pour plates. Fully ripened (> or =10 months) cheeses, derived from other milk lots, were also tested. Numbers of presumptive staphylococci (Baird-Parker agar [B-P]) were determined in the partially and fully ripened cheeses. Presumptive enterococci were ubiquitous in raw milk, usually at levels of 2.1 to 3.0 log CFU/ml. Enterococci were detected in 11 (26%) of 42 pasteurized milk samples. Enterococci and staphylococci were detected in 39 (93%) and 6 (14%) of unripened cheeses and in 33 (80%) and 4 (10%) of partially ripened cheeses, respectively. Only eight and five samples of enterococci-positive unripened and partially ripened cheese, respectively, were made from pasteurized milk in which presumptive enterococci were detected. Of 42 samples of fully ripened cheese, 35 (83%) and 8 (19%), respectively, contained presumptive enterococci and staphylococci. Results suggest either that low numbers of presumptive enterococci survive pasteurization and cheese ripening or that contamination of cheese by enterococci occurs after pasteurization. Biochemical testing confirmed 63% of presumptive enterococci isolates. None of the 20 presumptive staphylococci isolates produced colonies typical of Staphylococcus aureus on B-P agar; the isolates were identified as 1 Staphylococcus epidermidis, 1 Staphylococcus xylosus, 2 Staphylococcus saprophyticus, 1 Staphylococcus warneri, 5 Kocuria spp., and 10 unidentified gram-positive, catalase-positive cocci. Three staphylococci isolates decreased in numbers by more than 3.0 log CFU/ml in 9.9 ml of skim milk heated 30 min in a 62.8 degrees C water bath. This finding suggests that most presumptive staphylococci detected may have been prepasteurization contaminants. Unless specificity of the kanamycin esculin

  17. Linezolid-resistant clinical isolates of enterococci and Staphylococcus cohnii from a multicentre study in China: molecular epidemiology and resistance mechanisms.

    PubMed

    Chen, Hongbin; Wu, Weiyuan; Ni, Ming; Liu, Yingmei; Zhang, Jixia; Xia, Fei; He, Wenqiang; Wang, Qi; Wang, Zhanwei; Cao, Bin; Wang, Hui

    2013-10-01

    Genetic characterisation of linezolid-resistant Gram-positive cocci in a multicentre study in China has not been reported previously. To study the mechanism underlying the resistance of linezolid-resistant isolates, nine Enterococcus faecalis, one Enterococcus faecium and three Staphylococcus cohnii isolates with various levels of resistance were collected from five hospitals across China in 2009-2012. The nine E. faecalis isolates were classified into seven sequence types, indicating that these linezolid-resistant E. faecalis isolates were polyclonal. Enterococci isolates had reduced susceptibility to linezolid (MICs of 4-8 mg/L) and had mutation of ribosomal protein L3, with three also having mutation of L4, but without the multidrug resistance gene cfr or the 23S rRNA mutation G2576T. The three S. cohnii isolates were highly resistant to linezolid (MICs of 64 mg/L to >256 mg/L), harboured the cfr gene and had the 23S rRNA mutation G2576T. Southern blotting indicated that the cfr gene of these three isolates resided on different plasmids (pHK01, pRM01 and pRA01). In plasmid pHK01, IS21-558 and the cfr gene were integrated into transposon Tn558. In plasmids pRM01 and pRA01, the cfr gene was flanked by two copies of an IS256-like insertion sequence, indicating that the transferable form of linezolid resistance is conferred by the cfr gene. In conclusion, the emergence of linezolid-resistant Gram-positive cocci in different regions of China is of concern. The cfr gene and the 23S rRNA mutation contribute to high-level linezolid resistance in S. cohnii, and the L3 and L4 mutations are associated with low-level linezolid resistance in enterococci.

  18. Evidence for occurrence, persistence, and growth potential of Escherichia coli and enterococci in Hawaii’s soil environments

    USGS Publications Warehouse

    Byappanahalli, Muruleedhara N.; Roll, Bruce M.; Fujioka, Roger S.

    2012-01-01

    High densities of Escherichia coli and enterococci are common in freshwaters on Oahu and other Hawaiian Islands. Soil along stream banks has long been suspected as the likely source of these bacteria; however, the extent of their occurrence and distribution in a wide range of soils remained unknown until the current investigation. Soil samples representing the seven major soil associations were collected on the island of Oahu and analyzed for fecal coliforms, E. coli, and enterococci by the most probable number method. Fecal coliforms, E. coli, and enterococci were found in most of the samples analyzed; log mean densities (MPN ± SE g soil−1) were 1.96±0.18, n=61; 1.21±0.17, n=57; and 2.99±0.12, n=62, respectively. Representative, presumptive cultures of E. coli and enterococci collected from the various soils were identified and further speciated using the API scheme; at least six species of Enterococcus, including Enterococcus faecalis and Enterococcus faecium, were identified. In mesocosm studies, E. coli and enterococci increased by 100-fold in 4 days, after mixing sewage-spiked soil (one part) with autoclaved soil (nine parts). E. coli remained metabolically active in the soil and readily responded to nutrients, as evidenced by increased dehydrogenase activity. Collectively, these findings indicate that populations of E. coli and enterococci are part of the natural soil microflora, potentially influencing the quality of nearby water bodies.

  19. Evidence for Occurrence, Persistence, and Growth Potential of Escherichia coli and Enterococci in Hawaii’s Soil Environments

    PubMed Central

    Byappanahalli, Muruleedhara N.; Roll, Bruce M.; Fujioka, Roger S.

    2012-01-01

    High densities of Escherichia coli and enterococci are common in freshwaters on Oahu and other Hawaiian Islands. Soil along stream banks has long been suspected as the likely source of these bacteria; however, the extent of their occurrence and distribution in a wide range of soils remained unknown until the current investigation. Soil samples representing the seven major soil associations were collected on the island of Oahu and analyzed for fecal coliforms, E. coli, and enterococci by the most probable number method. Fecal coliforms, E. coli, and enterococci were found in most of the samples analyzed; log mean densities (MPN ± SE g soil−1) were 1.96±0.18, n=61; 1.21±0.17, n=57; and 2.99±0.12, n=62, respectively. Representative, presumptive cultures of E. coli and enterococci collected from the various soils were identified and further speciated using the API scheme; at least six species of Enterococcus, including Enterococcus faecalis and Enterococcus faecium, were identified. In mesocosm studies, E. coli and enterococci increased by 100-fold in 4 days, after mixing sewage-spiked soil (one part) with autoclaved soil (nine parts). E. coli remained metabolically active in the soil and readily responded to nutrients, as evidenced by increased dehydrogenase activity. Collectively, these findings indicate that populations of E. coli and enterococci are part of the natural soil microflora, potentially influencing the quality of nearby water bodies. PMID:22791049

  20. Routine Molecular Identification of Enterococci by Gene-Specific PCR and 16S Ribosomal DNA Sequencing

    PubMed Central

    Angeletti, Silvia; Lorino, Giulia; Gherardi, Giovanni; Battistoni, Fabrizio; De Cesaris, Marina; Dicuonzo, Giordano

    2001-01-01

    For 279 clinically isolated specimens identified by commercial kits as enterococci, genotypic identification was performed by two multiplex PCRs, one with ddlE. faecalis and ddlE. faecium primers and another with vanC-1 and vanC-2/3 primers, and by 16S ribosomal DNA (rDNA) sequencing. For 253 strains, phenotypic and genotypic results were the same. Multiplex PCR allowed for the identification of 13 discordant results. Six strains were not enterococci and were identified by 16S rDNA sequencing. For 5 discordant and 10 concordant enterococcal strains, 16S rDNA sequencing was needed. Because many supplementary tests are frequently necessary for phenotypic identification, the molecular approach is a good alternative. PMID:11158155

  1. Genotypic Diversity, Antibiotic Resistance and Bacteriocin Production of Enterococci Isolated from Rhizospheres

    PubMed Central

    Klibi, Naouel; Ben Slimen, Naouel; Fhoula, Imen; López, Maria; Ben Slama, Karim; Daffonchio, Daniele; Boudabous, Abdellatif; Torres, Carmen; Ouzari, Hadda

    2012-01-01

    This study aimed to identify and to characterize rhizospheric-derived enterococci. The results showed the prevalence of Enterococcus faecium species (97%) vs. Enterococcus durans (3%). Susceptibility testing for antibiotics showed a low percentage of resistance to erythromycin (3.2%) and tetracycline (11.2%), and intermediate resistance to vancomycin (6.5%). Nevertheless, a high proportion of bacteriocin production was recorded. Furthermore, PCR detection of antibiotic resistance and bacteriocin production-encoding genes was investigated. Pulsed-field gel electrophoresis typing (PFGE) showed a great variability of enterococci in the rhizosphere. Moreover, mutilocus-sequence-typing analysis (MLST) revealed the identification of three new sequence types (STs), which were registered as ST613, ST614 and ST615. PMID:23124764

  2. Selective media for detecting gastrointestinal carriage of vancomycin-resistant enterococci.

    PubMed

    Barton, A L; Doern, G V

    1995-11-01

    Nosocomial infection with vancomycin-resistant enterococci (VRE) has become a significant problem. Effective institution of infection control measures depends on rapid identification of carriage of the organism, especially in asymptomatic individuals. We compared two selective media for use in screening for the presence of VRE and found that an agar medium containing bile esculin azide supplemented with 8 mu g/ml of vancomycin was a useful and cost-effective means for primary screening for asymptomatic gastrointestinal carriage of VRE.

  3. Virulence traits and antibiotic resistance among enterococci isolated from dogs with periodontal disease.

    PubMed

    Oliveira, Manuela; Tavares, Marta; Gomes, Diana; Touret, Tiago; São Braz, Berta; Tavares, Luís; Semedo-Lemsaddek, Teresa

    2016-06-01

    Periodontal disease - PD - is one of the most widespread diseases in dogs, but the role of this odontogenic infection in the dissemination of pathogenic bacteria present in the oral mucosa to other animals or pet owners is understudied. Trying to unveil the putative pathogenicity of enterococci present in the gums of dogs diagnosed with PD, thirty-two animals were investigated during routine visits to a private veterinary clinic. Seventy-one enterococci were recovered and characterized regarding species, genomic variability, virulence traits, antimicrobial resistance and biofilm-forming ability. Isolates were mainly identified as Enterococcus faecalis, with the large majority (95%) being able to produce biofilm. Regarding antibiotic resistance, all dog-enterococci were susceptible to ampicillin, amoxicillin/clavulanate, gentamicin-120, imipenem and vancomycin; while distinct levels of resistance were observed for chloramphenicol (10%), erythromycin (20%), streptomycin-300 (35%) and tetracycline (95%). For virulence traits incidence levels of 35% were observed for β-hemolysis and 25% for cylA, 25% for gelatinase and 35% for gelE; 85% harbor efaAfs and ebpABC; while ace, agg and esp are present respectively in 50, 30 and 10% of the dog-enterococci; efaAfm and acm were detected in all the Enterococcus faecium. Overall, the widespread prevalence of PD in dogs, associated with the close contact between companion animals, other animals and humans, may act as source for the dissemination of opportunistic pathogenic bacteria. Hence, aforementioned data on virulence and resistance features, emphasizes the need for active surveillance measures, such as the diagnose of PD in companion animals during routine visits to the veterinary clinic.

  4. Quantitative assessment of faecal shedding of β-lactam-resistant Escherichia coli and enterococci in dogs.

    PubMed

    Espinosa-Gongora, Carmen; Shah, Syed Qaswar Ali; Jessen, Lisbeth Rem; Bortolaia, Valeria; Langebæk, Rikke; Bjørnvad, Charlotte Reinhard; Guardabassi, Luca

    2015-12-31

    Quantitative data on faecal shedding of antimicrobial resistant bacteria are crucial to assess the risk of transmission from dogs to other animals as well as humans. In this study we investigated prevalence and concentrations of β-lactam-resistant Escherichia coli and enterococci in the faeces of 108 dogs presenting at a veterinary hospital in Denmark. The dogs had not been treated with antimicrobials for 4 weeks prior to the study. Total E. coli and enterococci were quantified by counts on MacConkey and Slanetz-Bartley, respectively. Resistant E. coli and enterococci were counted on the same media containing relevant antibiotic concentrations, followed by species identification using MALDI-TOF. Ampicillin- and cefotaxime-resistant E. coli were detected in 40% and 8% of the dogs, respectively, whereas approximately 15% carried ampicillin-resistant enterococci, mainly Enterococcus faecium. In the faeces of the carriers, the proportion of resistant strains in the total bacterial species population was on average 15% for both ampicillin-resistant E. coli (median faecal load 3.2×10(4)cfu/g) and E. faecium (5.8×10(2) cfu/g), and 4.6% for cefotaxime-resistant E. coli (8.6×10(3) cfu/g). Cefotaxime resistance was associated with the presence of blaCTX-M-1 (n=4), blaCMY-2 (n=4) or multiple mutations in the promoter and coding region of chromosomal ampC (n=1). Altogether the results indicate that the risks of zoonotic transmission of β-lactam-resistant bacteria via human exposure to canine faeces greatly vary amongst individual dogs and are influenced by unidentified factors other than recent antimicrobial use.

  5. [Vancomycin-resistant enterococci - the nature of resistance and risk of transmission from animals to humans].

    PubMed

    Hermanovská, Lýdia; Bardoň, Jan; Čermák, Pavel

    2016-06-01

    Enterococci are part of the normal intestinal flora of humans and animals. Under certain circumstances, they are capable of extraintestinal conversion to opportunistic pathogens. They cause endogenous as well as exogenous community and nosocomial infections. The gastrointestinal tract of mammals provides them with favorable conditions for acquisition and spread of resistance genes, for example to vancomycin (van), from other symbiotic bacteria. Thus, vancomycin-resistant enterococci (VRE) become potential reservoirs and vectors of the van genes. Their occurrence in the population of the Czech Republic was first reported by Kolář et al. in 1997. Some variants of the vanA gene cluster carried on Tn1546 which encode resistance to vancomycin are identical in humans and in animals. It means that animals, especially cattle, poultry and pigs, could be an important reservoir of VRE for humans. Kolář and Bardoň detected VRE in animals in the Czech Republic for the first time in 2000. In Europe, the glycopeptide antibiotic avoparcin, used as a growth stimulator, is responsible for selection of VRE strains in animals. Strains of Enterococcus faecium from animals may offer genes of antimicrobial resistance to other enterococci or they can be directly dangerous to human. This is demonstrated by finding isolates of E. faecalis from human patients and from pigs having very similar profiles of resistance and virulence genes. The goal of the paper was to point out the similarity between isolates of human and animal strains of enterococci resistant to vancomycin, and the possibility of their bilateral transfer between humans and animals.

  6. Occurrence and antimicrobial resistance of enterococci isolated from organic and conventional retail chicken.

    PubMed

    Kilonzo-Nthenge, A; Brown, A; Nahashon, S N; Long, D

    2015-04-01

    Antibiotic-resistant bacteria existing in agricultural environments may be transferred to humans through food consumption or more multifaceted environmental paths of exposure. Notably, enterococcal infections are becoming more challenging to treat as their resistance to antibiotics intensifies. In this study, the prevalence and antibiotic resistance profiles of enterococci in organic and conventional chicken from retail stores were analyzed. Of the total 343 retail chicken samples evaluated, 282 (82.2%) were contaminated with Enterococcus spp. The prevalence was higher in organic chicken (62.5%) than conventional chicken (37.5%). Enterococcus isolates were submitted to susceptibility tests against 12 antimicrobial agents. Among the isolates tested, streptomycin had the highest frequencies of resistance (69.1 and 100%) followed by erythromycin (38.5 and 80.0%), penicillin (14.1 and 88.5%), and kanamycin (11.3 and 76.9%) for organic and conventional isolates, respectively. Chloramphenicol had the lowest frequency (0.0 and 6.6%, respectively). The predominant species in raw chicken was E. faecium (27.3%), followed by E. gallinarum (6.0%), E. casseliflavus (2.1%), and E. durans (1.4%). These species were also found to be resistant to three or more antibiotics. The data indicated that antibiotic-resistant enterococci isolates were found in chicken whether it was organic or conventional. However, enterococci isolates that were resistant to antibiotics were less common in organic chicken (31.0%) when compared with those isolated from conventional chicken (43.6%). The results of this study suggest that raw retail organic and conventional chickens could be a source of antibiotic-resistant enterococci.

  7. Removal kinetic of Escherichia coli and enterococci in a laboratory pilot scale wastewater maturation pond.

    PubMed

    Ouali, A; Jupsin, H; Ghrabi, A; Vasel, J L

    2014-01-01

    During the last 15 years several authors studied the disinfection in waste stabilisation pond (WSP) and several empirical models were developed. There are huge differences between the models describing this process and there is really a need to improve the design of ponds for better disinfection. This paper addresses the Escherichia coli and enterococci disinfection in a laboratory pilot scale maturation pond (1.5 l) with light intensity (0, 12 and 25 W/m(2)) under controlled pH, temperature and dissolved oxygen (DO) conditions. The aim of this study is to improve modelling for a better design of disinfection in maturation ponds (MP) and to identify the key parameters influencing the process. It was found that kinetic coefficients K values for E. coli and enterococci are closely dependent on physicochemical parameters. K values increase with increasing pH, I, T and DO. E. coli disinfection depends closely on the pH and the DO and increases strongly when the pH is above 8.5. The enterococci disinfection depends essentially on DO. Two equations are suggested to calculate the kinetic coefficient K related to the environmental average state variables.

  8. Safety and potential risks of enterococci isolated from traditional fermented capers.

    PubMed

    Pérez-Pulido, R; Abriouel, H; Ben Omar, N; Lucas, R; Martínez-Cañamero, M; Gálvez, A

    2006-12-01

    A collection of 17 enterococci isolates obtained from fermentations of capers (the fruits of Capparis sp.) were investigated for incidence of known virulence determinants, antibiotic resistance and production of biogenic amines. Molecular identification revealed the presence of Enterococcus faecium (nine isolates), Enterococcus faecalis (4), E. avium (3) and Enterococcus casseliflavus/flavescens (1). Alpha-haemolytic activity was detected in two E. avium and one E. faecalis isolates, and beta-haemolytic activity was detected in E. casseliflavus/flavescens. The haemolytic component cylB was detected by PCR amplification in three non-haemolytic isolates and in E. casseliflavus/flavescens. The collagen adhesin ace gene and the endocarditis associated antigen gene efaA(fm) were detected in two isolates each. Genes encoding sex pheromone precursors (cpd, cob, ccf) were detected in E. faecalis and E. casseliflavus/flavescens. Other presumed virulence genes (agg, gelE, cylM, cylA and efaA(fs)) were not detected. All isolates were resistant to rifampicin, erythromycin and ciprofloxacin, and some were also resistant to quinupristin/dalfopristin, tetracycline, levofloxacin, gentamicin and streptomycin. Vancomycin resistance was not detected. Tyrosine decarboxylation was detected in all E. faecium isolates. Given the high resistance of enterococci to environmental conditions, and their implication in opportunistic infections, the incidence of potential virulent enterococci in foods (especially those of a higher risk-like home-made foods) should be carefully studied.

  9. Vancomycin-variable enterococci can give rise to constitutive resistance during antibiotic therapy.

    PubMed

    Thaker, Maulik N; Kalan, Lindsay; Waglechner, Nicholas; Eshaghi, Alireza; Patel, Samir N; Poutanen, Susan; Willey, Barbara; Coburn, Bryan; McGeer, Allison; Low, Donald E; Wright, Gerard D

    2015-03-01

    Vancomycin-resistant enterococci (VRE) are notorious clinical pathogens restricting the use of glycopeptide antibiotics in the clinic setting. Routine surveillance to detect VRE isolated from patients relies on PCR bioassays and chromogenic agar-based test methods. In recent years, we and others have reported the emergence of enterococcal strains harboring a "silent" copy of vancomycin resistance genes that confer a vancomycin-susceptible phenotype (vancomycin-susceptible enterococci [VSE]) and thus escape detection using drug sensitivity screening tests. Alarmingly, these strains are able to convert to a resistance phenotype (VSE→VRE) during antibiotic treatment, severely compromising the success of therapy. Such strains have been termed vancomycin-variable enterococci (VVE). We have investigated the molecular mechanisms leading to the restoration of resistance in VVE isolates through the whole-genome sequencing of resistant isolates, measurement of resistance gene expression, and quantification of the accumulation of drug-resistant peptidoglycan precursors. The results demonstrate that VVE strains can revert to a VRE phenotype through the constitutive expression of the vancomycin resistance cassette. This is accomplished through a variety of changes in the DNA region upstream of the resistance genes that includes both a deletion of a likely transcription inhibitory secondary structure and the introduction of a new unregulated promoter. The VSE→VRE transition of VVE can occur in patients during the course of antibiotic therapy, resulting in treatment failure. These VVE strains therefore pose a new challenge to the current regimen of diagnostic tests used for VRE detection in the clinic setting.

  10. Detection and enumeration of fecal indicator organisms in frozen sea foods. II. Enterococci.

    PubMed

    RAJ, H; WIEBE, W J; LISTON, J

    1961-07-01

    Consistently high recoveries of enterococci as compared to the low numbers of coliforms obtained from the same samples of frozen sea foods are indirect evidence that enterococci are better indicators of contamination in such foods. The use of azide dextrose broth, modified by the incorporation of bromthymol blue, and of ethyl violet azide broth as presumptive and confirmation tests, respectively, were found to be highly specific for the detection and enumeration of enterococci in these samples. Tetrazolium agar medium, when used as a third step after the confirmation test, provides a reliable differentiation of Streplococcus faecalis types from other group D streptococci. A simple procedure is described for further identification of S. faecalis varieties and other enterococcal species. Incidence of biotypes within certain species is noted and relationships of these subgroups to the organisms described by other workers is discussed. The striking resistance of all group D streptococci to dihydrostreptomycin and polymyxin B seems to offer promise for evolving a new selective medium for these organisms.

  11. Comparison of agar-based media for primary isolation of glycopeptide-resistant enterococci.

    PubMed

    Chadwick, P. R.; Brown, D. F. J.; Wilcox, M. H.; Collyns, T. A.; Walpole, E.; Dillon, J.; Smith, R.; Gopal Rao, G.; Oppenheim, B. A.

    1997-01-01

    OBJECTIVE: To compare four vancomycin-containing agar media for the isolation of glycopeptide-resistant enterococci (GRE) from clinical fecal specimens: kanamycin---aesculin---azide (KAA) agar; bile---aesculin---polymixin (BAP) agar; aztreonam---amphotericin blood (CBAA) agar; and neomycin blood (CBN) agar. METHODS: Fecal specimens from 125 patients were inoculated onto each medium. Media were examined for enterococci after incubation for up to 48 h. Enterococci were identified to species level, and glycopeptide phenotypes were determined by measuring minimum inhibitory concentrations of vancomycin and teicoplanin. RESULTS: GRE were isolated from 44/125 samples. Enterococcus faecalis and Enterococcus faecium isolates, expressing glycopeptide resistance of the VanA or VanB phenotypes, were recovered from 27/33 (82%) specimens on BAP medium, 26/33 (79%) on KAA medium, and 21/33 (64%) on CBN and CBAA media. Enterococcus gallinarum and Enterococcus casseliflavus isolates expressing low-level glycopeptide resistance (VanC phenotype) were recovered from 14/15 (93%) specimens on CBAA medium, 7/15 (47%) on KAA and CBN media, and 6/15 (40%) on BAP medium. CONCLUSIONS: The media tested in this study, with the exception of CBN medium, detected at least 75% of patients colonized by GRE. Further development of BAP, CBAA and KAA media is warranted to improve growth and selectivity.

  12. Vancomycin-resistant enterococci: why are they here, and where do they come from?

    PubMed

    Bonten, M J; Willems, R; Weinstein, R A

    2001-12-01

    Vancomcyin-resistant enterococci (VRE) have emerged as nosocomial pathogens in the past 10 years, causing epidemiological controversy. In the USA, colonisation with VRE is endemic in many hospitals and increasingly causes infection, but colonisation is absent in healthy people. In Europe, outbreaks still happen sporadically, usually with few serious infections, but colonisation seems to be endemic in healthy people and farm animals. Vancomycin use has been much higher in the USA, where emergence of ampicillin-resistant enterococci preceded emergence of VRE, making them very susceptible to the selective effects of antibiotics. In Europe, avoparcin, a vancomycin-like glycopeptide, has been widely used in the agricultural industry, explaining the community reservoir in European animals. Avoparcin has not been used in the USA, which is consistent with the absence of colonisation in healthy people. From the European animal reservoir, VRE and resistance genes have spread to healthy human beings and hospitalised patients. However, certain genogroups of enterococci in both continents seem to be more capable of causing hospital outbreaks, perhaps because of the presence of a specific virulence factor, the variant esp gene. By contrast with the evidence of a direct link between European animal and human reservoirs, the origin of American resistance genes remains to be established. Considering the spread of antibiotic-resistant bacteria and resistance genes, the emergence of VRE has emphasised the non-existence of boundaries between hospitals, between people and animals, between countries, and probably between continents.

  13. Antimicrobial resistance and virulence genes in Escherichia coli and enterococci from red foxes (Vulpes vulpes).

    PubMed

    Radhouani, Hajer; Igrejas, Gilberto; Gonçalves, Alexandre; Pacheco, Rui; Monteiro, Ricardo; Sargo, Roberto; Brito, Francisco; Torres, Carmen; Poeta, Patrícia

    2013-10-01

    The aims of the study were to analyse the prevalence of antimicrobial resistance and the mechanisms implicated, as well as the virulence factors, in faecal Escherichia coli and Enterococcus spp. from red foxes. From 52 faecal samples, 22 E. coli (42.3%) and 50 enterococci (96.2%) isolates were recovered (one/sample). A high percentage of E. coli isolates exhibited resistance to streptomycin, tetracycline, trimethoprim-sulfamethoxazole or ampicillin (54-27%), and they harboured the aadA, tet(A) and/or tet(B), sul1 and blaTEM resistance genes, respectively. The E. coli isolates were ascribed to the 4 major phylogroups, D (41% of isolates), A (31.8%), B1 (18.2%) and B2 (9.1%), and carried the fimA (63.3%) or aer (13.6%) virulence genes. Among enterococcal isolates, Enterococcus faecium was the most prevalent species (50%). A high percentage of enterococcal isolates showed tetracycline resistance (88%) harbouring different combinations of tet(M) and tet(L) genes. The erm(B) or the aph(3')-IIIa gene were identified in most of our erythromycin- or kanamycin-resistant enterococci, respectively. This report suggests the role of red foxes from rural areas in the cycle of transmission and spread of antimicrobial-resistant E. coli and enterococci into the environment, representing a reservoir of these antimicrobial-resistant microorganisms.

  14. Decarboxylation activity of enterococci isolated from rabbit meat and staphylococci isolated from trout intestines.

    PubMed

    Pleva, Pavel; Buňková, Leona; Lauková, Andrea; Lorencová, Eva; Kubáň, Vlastimil; Buňka, František

    2012-10-12

    The aim of the study was to explore production of seven biogenic amines (phenylethylamine, histamine, cadaverine, tyramine, putrescine, spermine and/or spermidine) by selected staphylococci and enterococci. Thirty three enterococcal strains isolated from rabbit meat (Oryctolagus cuniculus f. domesticus) and 21 staphylococcal strains isolated from intestinal content of trout (Salmo trutta morpha fario) were tested. Production of biogenic amines was evaluated after cultivation of the tested microorganisms in the de Man, Rogosa and Sharpe Broth (enterococci) or in the Brain Heart Infusion Broth (staphylococci). Both the above cultivation media were enriched with selected amino acids (histidine, tyrosine, arginine, ornithine and lysine; 2g/L each) serving as precursors of biogenic amines. After cultivation, levels of the monitored biogenic amines in broths were analysed by a high performance liquid chromatography equipped with a UV/VIS DAD detector. Among 21 staphylococci, 18 strains produced tyramine or cadaverine, 13 strains formed putrescine or phenylethylamine and only one strain generated histamine. Two staphylococcal strains produced cadaverine levels above 1000 mg/L. Among 33 enterococcal strains, 27 formed cadaverine, 18 strains produced tyramine, 10 strains generated phenylethylamine, and 2 strains gave putrescine. Most of the tyramine producing enterococci generated more than 1000 mg/L of this biogenic amine. Production of spermine or spermidine by the studied strains was not proved.

  15. Reference commercial high-level waste glass and canister definition.

    SciTech Connect

    Slate, S.C.; Ross, W.A.; Partain, W.L.

    1981-09-01

    This report presents technical data and performance characteristics of a high-level waste glass and canister intended for use in the design of a complete waste encapsulation package suitable for disposal in a geologic repository. The borosilicate glass contained in the stainless steel canister represents the probable type of high-level waste product that will be produced in a commercial nuclear-fuel reprocessing plant. Development history is summarized for high-level liquid waste compositions, waste glass composition and characteristics, and canister design. The decay histories of the fission products and actinides (plus daughters) calculated by the ORIGEN-II code are presented.

  16. A risk modelling approach for setting microbiological limits using enterococci as indicator for growth potential of Salmonella in pork.

    PubMed

    Bollerslev, Anne Mette; Nauta, Maarten; Hansen, Tina Beck; Aabo, Søren

    2017-01-02

    Microbiological limits are widely used in food processing as an aid to reduce the exposure to hazardous microorganisms for the consumers. However, in pork, the prevalence and concentrations of Salmonella are generally low and microbiological limits are not considered an efficient tool to support hygiene interventions. The objective of the present study was to develop an approach which could make it possible to define potential risk-based microbiological limits for an indicator, enterococci, in order to evaluate the risk from potential growth of Salmonella. A positive correlation between the concentration of enterococci and the prevalence and concentration of Salmonella was shown for 6640 pork samples taken at Danish cutting plants and retail butchers. The samples were collected in five different studies in 2001, 2002, 2010, 2011 and 2013. The observations that both Salmonella and enterococci are carried in the intestinal tract, contaminate pork by the same mechanisms and share similar growth characteristics (lag phase and maximum specific growth rate) at temperatures around 5-10°C, suggest a potential of enterococci to be used as an indicator of potential growth of Salmonella in pork. Elevated temperatures during processing will lead to growth of both enterococci and, if present, also Salmonella. By combining the correlation between enterococci and Salmonella with risk modelling, it is possible to predict the risk of salmonellosis based on the level of enterococci. The risk model used for this purpose includes the dose-response relationship for Salmonella and a reduction factor to account for preparation of the fresh pork. By use of the risk model, it was estimated that the majority of salmonellosis cases, caused by the consumption of pork in Denmark, is caused by the small fraction of pork products that has enterococci concentrations above 5logCFU/g. This illustrates that our approach can be used to evaluate the potential effect of different microbiological

  17. Neptunium estimation in dissolver and high-level-waste solutions

    SciTech Connect

    Pathak, P.N.; Prabhu, D.R.; Kanekar, A.S.; Manchanda, V.K.

    2008-07-01

    This papers deals with the optimization of the experimental conditions for the estimation of {sup 237}Np in spent-fuel dissolver/high-level waste solutions using thenoyltrifluoroacetone as the extractant. (authors)

  18. Holism and High Level Wellness in the Treatment of Alcoholism.

    ERIC Educational Resources Information Center

    Bartha, Robert; Davis, Tom

    1982-01-01

    Discusses how a holistic and wellness philosophy is a viable alternative in the treatment of alcoholism. Describes five major dimensions of high-level wellness: nutritional awareness, physical fitness, stress management, environmental sensitivity, and self-responsibility. (RC)

  19. High-Level Waste System Process Interface Description

    SciTech Connect

    d'Entremont, P.D.

    1999-01-14

    The High-Level Waste System is a set of six different processes interconnected by pipelines. These processes function as one large treatment plant that receives, stores, and treats high-level wastes from various generators at SRS and converts them into forms suitable for final disposal. The three major forms are borosilicate glass, which will be eventually disposed of in a Federal Repository, Saltstone to be buried on site, and treated water effluent that is released to the environment.

  20. Comparative Study of Bacteremias Caused by Enterococcus spp. with and without High-Level Resistance to Gentamicin

    PubMed Central

    Caballero-Granado, Francisco Javier; Cisneros, J. M.; Luque, R.; Torres-Tortosa, M.; Gamboa, F.; Díez, F.; Villanueva, J. L.; Pérez-Cano, R.; Pasquau, J.; Merino, D.; Menchero, A.; Mora, D.; López-Ruz, M. A.; Vergara, A.; Infecciosas, for the Grupo Andaluz Para El Estudio De Las Enfermedades

    1998-01-01

    A prospective, multicenter study was carried out over a period of 10 months. All patients with clinically significant bacteremia caused by Enterococcus spp. were included. The epidemiological, microbiological, clinical, and prognostic features and the relationship of these features to the presence of high-level resistance to gentamicin (HLRG) were studied. Ninety-three patients with enterococcal bacteremia were included, and 31 of these cases were caused by HLRG (33%). The multivariate analysis selected chronic renal failure, intensive care unit stay, previous use of antimicrobial agents, and Enterococcus faecalis species as the independent risk factors that influenced the development of HLRG. The strains with HLRG showed lower levels of susceptibility to penicillin and ciprofloxacin. Clinical features (except for chronic renal failure) were similar in both groups of patients. HLRG did not influence the prognosis for patients with enterococcal bacteremia in terms of either the crude mortality rate (29% for patients with bacteremia caused by enterococci with HLRG and 28% for patients not infected with strains with HLRG) or the hospital stay after the acquisition of enterococcal bacteremia. Hemodynamic compromise, inappropriate antimicrobial therapy, and mechanical ventilation were revealed in the multivariate analysis to be the independent risk factors for mortality. Prolonged hospitalization was associated with the nosocomial acquisition of bacteremia and polymicrobial infections. PMID:9466769

  1. Antibiotic-Resistant Enterococci and Fecal Indicators in Surface Water and Groundwater Impacted by a Concentrated Swine Feeding Operation

    PubMed Central

    Sapkota, Amy R.; Curriero, Frank C.; Gibson, Kristen E.; Schwab, Kellogg J.

    2007-01-01

    Background The nontherapeutic use of antibiotics in swine feed can select for antibiotic resistance in swine enteric bacteria. Leaking swine waste storage pits and the land-application of swine manure can result in the dispersion of resistant bacteria to water sources. However, there are few data comparing levels of resistant bacteria in swine manure–impacted water sources versus unaffected sources. Objectives The goal of this study was to analyze surface water and groundwater situated up and down gradient from a swine facility for antibiotic-resistant enterococci and other fecal indicators. Methods Surface water and groundwater samples (n = 28) were collected up and down gradient from a swine facility from 2002 to 2004. Fecal indicators were isolated by membrane filtration, and enterococci (n = 200) were tested for susceptibility to erythromycin, tetracycline, clindamycin, virginiamycin, and vancomycin. Results Median concentrations of enterococci, fecal coliforms, and Escherichia coli were 4- to 33-fold higher in down-gradient versus up-gradient surface water and groundwater. We observed higher minimal inhibitory concentrations for four antibiotics in enterococci isolated from down-gradient versus up-gradient surface water and groundwater. Elevated percentages of erythromycin- (p = 0.02) and tetracycline-resistant (p = 0.06) enterococci were detected in down-gradient surface waters, and higher percentages of tetracycline- (p = 0.07) and clindamycin-resistant (p < 0.001) enterococci were detected in down-gradient groundwater. Conclusions We detected elevated levels of fecal indicators and antibiotic-resistant enterococci in water sources situated down gradient from a swine facility compared with up-gradient sources. These findings provide additional evidence that water contaminated with swine manure could contribute to the spread of antibiotic resistance. PMID:17637920

  2. Effect of in-feed administration and withdrawal of tylosin phosphate on antibiotic resistance in enterococci isolated from feedlot steers

    PubMed Central

    Beukers, Alicia G.; Zaheer, Rahat; Cook, Shaun R.; Stanford, Kim; Chaves, Alexandre V.; Ward, Michael P.; McAllister, Tim A.

    2015-01-01

    Tylosin phosphate is a macrolide commonly administered to cattle in North America for the control of liver abscesses. This study investigated the effect of in-feed administration of tylosin phosphate to cattle at subtherapeutic levels and its subsequent withdrawal on macrolide resistance using enterococci as an indicator bacterium. Fecal samples were collected from steers that received no antibiotics and steers administered tylosin phosphate (11 ppm) in-feed for 197 days and withdrawn 28 days before slaughter. Enterococcus species isolated from fecal samples were identified through sequencing the groES-EL intergenic spacer region and subject to antimicrobial susceptibility testing, identification of resistance determinants and pulsed-field gel electrophoresis profiling. Tylosin increased (P < 0.05) the proportion of eryR and tylR enterococci within the population. Just prior to its removal, the proportion of eryR and tylR resistant enterococci began decreasing and continued to decrease after tylosin was withdrawn from the diet until there was no difference (P > 0.05) between treatments on d 225. This suggests that antibiotic withdrawal prior to slaughter contributes to a reduction in the proportion of macrolide resistant enterococci entering the food chain. Among the 504 enterococci isolates characterized, Enterococcus hirae was found to predominate (n = 431), followed by Enterococcus villorum (n = 32), Enterococcus faecium (n = 21), Enterococcus durans (n = 7), Enterococcus casseliflavus (n = 4), Enterococcus mundtii (n = 4), Enterococcus gallinarum (n = 3), Enterococcus faecalis (n = 1), and Enterococcus thailandicus (n = 1). The diversity of enterococci was greater in steers at arrival than at exit from the feedlot. Erythromycin resistant isolates harbored the erm(B) and/or msrC gene. Similar PFGE profiles of eryR E. hirae pre- and post-antibiotic treatment suggest that increased abundance of eryR enterococci after administration of tylosin phosphate reflects

  3. Effect of in-feed administration and withdrawal of tylosin phosphate on antibiotic resistance in enterococci isolated from feedlot steers.

    PubMed

    Beukers, Alicia G; Zaheer, Rahat; Cook, Shaun R; Stanford, Kim; Chaves, Alexandre V; Ward, Michael P; McAllister, Tim A

    2015-01-01

    Tylosin phosphate is a macrolide commonly administered to cattle in North America for the control of liver abscesses. This study investigated the effect of in-feed administration of tylosin phosphate to cattle at subtherapeutic levels and its subsequent withdrawal on macrolide resistance using enterococci as an indicator bacterium. Fecal samples were collected from steers that received no antibiotics and steers administered tylosin phosphate (11 ppm) in-feed for 197 days and withdrawn 28 days before slaughter. Enterococcus species isolated from fecal samples were identified through sequencing the groES-EL intergenic spacer region and subject to antimicrobial susceptibility testing, identification of resistance determinants and pulsed-field gel electrophoresis profiling. Tylosin increased (P < 0.05) the proportion of ery(R) and tyl(R) enterococci within the population. Just prior to its removal, the proportion of ery(R) and tyl(R) resistant enterococci began decreasing and continued to decrease after tylosin was withdrawn from the diet until there was no difference (P > 0.05) between treatments on d 225. This suggests that antibiotic withdrawal prior to slaughter contributes to a reduction in the proportion of macrolide resistant enterococci entering the food chain. Among the 504 enterococci isolates characterized, Enterococcus hirae was found to predominate (n = 431), followed by Enterococcus villorum (n = 32), Enterococcus faecium (n = 21), Enterococcus durans (n = 7), Enterococcus casseliflavus (n = 4), Enterococcus mundtii (n = 4), Enterococcus gallinarum (n = 3), Enterococcus faecalis (n = 1), and Enterococcus thailandicus (n = 1). The diversity of enterococci was greater in steers at arrival than at exit from the feedlot. Erythromycin resistant isolates harbored the erm(B) and/or msrC gene. Similar PFGE profiles of ery(R) E. hirae pre- and post-antibiotic treatment suggest that increased abundance of ery(R) enterococci after administration of tylosin phosphate

  4. Antibiotics and heavy metals resistance and other biological characters in enterococci isolated from surface water of Monte Cotugno Lake (Italy).

    PubMed

    De Niederhäusern, Simona; Bondi, Moreno; Anacarso, Immacolata; Iseppi, Ramona; Sabia, Carla; Bitonte, Fabiano; Messi, Patrizia

    2013-01-01

    Considering the limited knowledge about the biological characters in enterococci isolated from surface waters, we investigated antibiotic and heavy-metal resistance, bacteriocin production, and some important virulence traits of 165 enterococci collected in water samples from Monte Cotugno Lake, the largest artificial basin built with earth in Europe. The species distribution of isolates was as follows: Enterococcus faecium (80%), Enterococcus faecalis (12.7%), Enterococcus casseliflavus (3%), Enterococcus mundtii (1.8%), Enterococcus hirae (1.8%), Enterococcus durans (0.6%). All enterococci showed heavy metal resistance toward Cu, Ni, Pb and Zn, were susceptible to Ag and Hg, and at the same time exhibited in large percentage (83.7%) resistance to one or more of the antibiotics tested. Relatively to virulence factor genes, 50.9% enterococci were positive for gelatinase (gelE), 10.9% for aggregation substance (agg), 12.7% and 66.6% for the cell wall adhesins (efaAfs and efaAfm), respectively. No amplicons were detected after PCR for cytolysin production (cylA, cylB and cylM) and enterococcal surface protein (esp) genes. Bacteriocin production was found in most of the isolates. Given that the waters of the Monte Cotugno Lake are used for different purposes, among which farming and recreational activities, they can contribute to spread enterococci endowed with virulence factors, and antibiotics and heavy metals resistance to humans.

  5. An overview of very high level software design methods

    NASA Technical Reports Server (NTRS)

    Asdjodi, Maryam; Hooper, James W.

    1988-01-01

    Very High Level design methods emphasize automatic transfer of requirements to formal design specifications, and/or may concentrate on automatic transformation of formal design specifications that include some semantic information of the system into machine executable form. Very high level design methods range from general domain independent methods to approaches implementable for specific applications or domains. Applying AI techniques, abstract programming methods, domain heuristics, software engineering tools, library-based programming and other methods different approaches for higher level software design are being developed. Though one finds that a given approach does not always fall exactly in any specific class, this paper provides a classification for very high level design methods including examples for each class. These methods are analyzed and compared based on their basic approaches, strengths and feasibility for future expansion toward automatic development of software systems.

  6. High Level Waste (HLW) Feed Process Control Strategy

    SciTech Connect

    STAEHR, T.W.

    2000-06-14

    The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system.

  7. High level radioactive waste management facility design criteria

    SciTech Connect

    Sheikh, N.A.; Salaymeh, S.R.

    1993-10-01

    This paper discusses the engineering systems for the structural design of the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). At the DWPF, high level radioactive liquids will be mixed with glass particles and heated in a melter. This molten glass will then be poured into stainless steel canisters where it will harden. This process will transform the high level waste into a more stable, manageable substance. This paper discuss the structural design requirements for this unique one of a kind facility. A special emphasis will be concentrated on the design criteria pertaining to earthquake, wind and tornado, and flooding.

  8. Final report on cermet high-level waste forms

    SciTech Connect

    Kobisk, E.H.; Quinby, T.C.; Aaron, W.S.

    1981-08-01

    Cermets are being developed as an alternate method for the fixation of defense and commercial high level radioactive waste in a terminal disposal form. Following initial feasibility assessments of this waste form, consisting of ceramic particles dispersed in an iron-nickel base alloy, significantly improved processing methods were developed. The characterization of cermets has continued through property determinations on samples prepared by various methods from a variety of simulated and actual high-level wastes. This report describes the status of development of the cermet waste form as it has evolved since 1977. 6 tables, 18 figures.

  9. High-Level Event Recognition in Unconstrained Videos

    DTIC Science & Technology

    2013-01-01

    for polyphonic music. J Acoust Soc Am 122( 2 ):881–891 6. Aytar Y, ShahM, Luo J (2008) Utilizing semantic word similarity measures for video retrieval...Int J Multimed Info Retr (2013) 2 :73–101 DOI 10.1007/s13735-012-0024- 2 TRENDS AND SURVEYS High-level event recognition in unconstrained videos Yu...mob”). Techniques for recognizing such high-level events are essential for many practical applications such as Web video search, consumer video

  10. Emergence of Vancomycin-resistant Enterococci at a Teaching Hospital, Saudi Arabia

    PubMed Central

    Alotaibi, Fawzia E; Bukhari, Elham E

    2017-01-01

    Background: Vancomycin-resistant enterococci (VRE) are a major and emerging hospital-acquired pathogen associated with high mortality, particularly among the critically ill and Intensive Care Units (ICUs) patients. This study aimed to determine the prevalence and demographic and clinical characteristics of VRE among patients admitted to a university hospital in Riyadh, Saudi Arabia. Methods: A study was conducted during the period from September 2014 to November 2015 at King Khalid University Hospital, a tertiary care hospital in Riyadh, Saudi Arabia, including in-patients with VRE infection. Data were collected using laboratory results and the medical records of admitted patients and were analyzed using SPSS version 19.0 statistical software. Results: In a one-year period, 231 enterococci were isolated from blood, urine, exudates, sputum, stool, and body fluid. There were 191 (82.7%) vancomycin-sensitive enterococci (VSE) and 40 (17.3%) isolates were VRE. The Enterococcus species included E. faecalis 168 (72.7%), E. faecium, 53 (22.8%) E. gallinarum 5 (2.2%), and E. avium 5 (2.2%). VRE were more significant from blood specimens (P < 0.0001) while VSE were significantly more predominant from urine specimens (P < 0.0001). VRE were more commonly isolated from patients in ICUs and oncology unit (P = 0.0151 and P < 0.001, respectively) while VSE were more predominant in the medical and surgical areas (P = 0.0178 and P = 0.0178, respectively). Conclusions: This study highlights the high prevalence of VRE in the hospital and the association of enterococcal infections with high-risk areas and oncology units, which warrant more studies looking for better management of these infections. PMID:28139519

  11. Ecology of Antibiotic Resistance Genes: Characterization of Enterococci from Houseflies Collected in Food Settings†

    PubMed Central

    Macovei, Lilia; Zurek, Ludek

    2006-01-01

    In this project, enterococci from the digestive tracts of 260 houseflies (Musca domestica L.) collected from five restaurants were characterized. Houseflies frequently (97% of the flies were positive) carried enterococci (mean, 3.1 × 103 CFU/fly). Using multiplex PCR, 205 of 355 randomly selected enterococcal isolates were identified and characterized. The majority of these isolates were Enterococcus faecalis (88.2%); in addition, 6.8% were E. faecium, and 4.9% were E. casseliflavus. E. faecalis isolates were phenotypically resistant to tetracycline (66.3%), erythromycin (23.8%), streptomycin (11.6%), ciprofloxacin (9.9%), and kanamycin (8.3%). Tetracycline resistance in E. faecalis was encoded by tet(M) (65.8%), tet(O) (1.7%), and tet(W) (0.8%). The majority (78.3%) of the erythromycin-resistant E. faecalis isolates carried erm(B). The conjugative transposon Tn916 and members of the Tn916/Tn1545 family were detected in 30.2% and 34.6% of the identified isolates, respectively. E. faecalis carried virulence genes, including a gelatinase gene (gelE; 70.7%), an aggregation substance gene (asa1; 33.2%), an enterococcus surface protein gene (esp; 8.8%), and a cytolysin gene (cylA; 8.8%). Phenotypic assays showed that 91.4% of the isolates with the gelE gene were gelatinolytic and that 46.7% of the isolates with the asa1 gene aggregated. All isolates with the cylA gene were hemolytic on human blood. This study showed that houseflies in food-handling and -serving facilities carry antibiotic-resistant and potentially virulent enterococci that have the capacity for horizontal transfer of antibiotic resistance genes to other bacteria. PMID:16751512

  12. Speciation and antimicrobial resistance of Enterococci isolated from recreational beaches in Malaysia.

    PubMed

    Dada, Ayokunle Christopher; Ahmad, Asmat; Usup, Gires; Heng, Lee Yook

    2013-02-01

    We report the first study on the occurrence of antibiotic-resistant enterococci in coastal bathing waters in Malaysia. One hundred and sixty-five enterococci isolates recovered from two popular recreational beaches in Malaysia were speciated and screened for antibiotic resistance to a total of eight antibiotics. Prevalence of Enterococcus faecalis and Enterococcus faecium was highest in both beaches. E. faecalis/E. faecium ratio was 0.384:1 and 0.375:1, respectively, for isolates from Port Dickson (PD) and Bagan Lalang (BL). Analysis of Fisher's exact test showed that association of prevalence of E. faecalis and E. faecium with considered locations was not statistically significant (p < 0.05). Chi-square test revealed significant differences (χ(2) = 82.630, df = 20, p < 0.001) in the frequency of occurrence of enterococci isolates from the considered sites. Resistance was highest to nalidixic acid (94.84 %) and least for chloramphenicol (8.38 %). One-way ANOVA using Tukey-Kramer multiple comparison test showed that resistance to ampicillin was higher in PD beach isolates than BL isolates and the difference was extremely statistically significant (p < 0.0001). Frequency of occurrence of multiple antibiotic resistance (MAR) isolates were higher for PD beach water (64.29 %) as compared to BL beach water (13.51 %), while MAR indices ranged between 0.198 and 0.48. The results suggest that samples from Port Dickson may contain MAR bacteria and that this could be due to high-risk faecal contamination from sewage discharge pipes that drain into the sea water.

  13. Identification and prevalence of tetracycline resistance in enterococci isolated from poultry in Ilishan, Ogun State, Nigeria

    PubMed Central

    Ayeni, Funmilola A.; Odumosu, Bamidele Tolulope; Oluseyi, Adekola E.; Ruppitsch, Werner

    2016-01-01

    Background: Tetracycline is one of the most frequently used antibiotics in Nigeria both for human and animal infections because of its cheapness and ready availability. The use of tetracycline in animal husbandry could lead to horizontal transfer of tet genes from poultry to human through the gut microbiota, especially enterococci. Therefore, this study is designed to identify different enterococcal species from poultry feces in selected farms in Ilishan, Ogun State, Nigeria, determine the prevalence of tetracycline resistance/genes and presence of IS256 in enterococcal strains. Materials and Methods: Enterococci strains were isolated from 100 fresh chicken fecal samples collected from seven local poultry farms in Ilishan, Ogun State, Nigeria. The strains were identified by partial sequencing of 16S rRNA genes. Antibiotic susceptibility of the isolates to vancomycin, erythromycin, tetracycline, gentamicin, amoxycillin/claulanate, and of loxacin were performed by disc diffusion method. Detection of tet, erm, and van genes and IS256 insertion element were done by polymerase chain reaction amplification. Results: Sixty enterococci spp. were identified comprising of Enterococcus faecalis 33 (55%), Enterococcus casseliflavus 21 (35%), and Enterococcus gallinarium 6 (10%). All the isolates were resistant to erythromycin (100%), followed by tetracycline (81.67%), amoxicillin/clavulanic acid (73.33%), ofloxacin (68.33%), vancomycin (65%), and gentamicin (20%). None of the enterococcal spp. harbored the van and erm genes while tet(M) was detected among 23% isolates and is distributed mostly among E. casseliflavus. IS256 elements were detected only in 33% of E. casseliflavus that were also positive for tet(M) gene. Conclusion: This study provides evidence that tetracycline resistance gene is present in the studied poultry farms in Ilishan, Ogun State, Nigeria and underscores the need for strict regulation on tetracycline usage in poultry farming in the studied location and

  14. Temporal Variabilities in Genetic Patterns and Antibiotic Resistance Profiles of Enterococci Isolated from Human Feces

    PubMed Central

    Nishiyama, Masateru; Shimauchi, Hidetaka; Suzuki, Yoshihiro

    2016-01-01

    Temporal variabilities in the genetic patterns and antibiotic resistance profiles of enterococci were monitored over a 7-month period. Enterococcus faecalis isolates (103 strains) collected from feces showed only one genetic pattern and antibiotic resistance profile within 0 d and 30 d. In contrast, after 60 d and 90 d, the genetic patterns and antibiotic resistance profiles of all E. faecalis isolates (8 strains) clearly differed within 30 d. These results indicate that the genetic patterns and antibiotic resistance profiles of E. faecalis in human feces changed to completely dissimilar patterns between 1 and 2 months. PMID:27265342

  15. Comparison of Five Chromogenic Media for Recovery of Vancomycin-Resistant Enterococci from Fecal Samples

    PubMed Central

    Suwantarat, Nuntra; Roberts, Ava; Prestridge, Jamie; Seeley, Renee; Speser, Sharon; Harmon, Christopher; Zhang, Chi; Henciak, Susan; Stamper, Paul D.; Ross, Tracy

    2014-01-01

    Five chromogenic agars, evaluated using 400 stool specimens, were found to be superior in sensitivity (range, 89.9 to 93.9%) to bile esculin azide agar with vancomycin (BEAV) agar (84.8%) for detecting vancomycin-resistant enterococci (VRE), and the results were available 24 to 48 h sooner. The time to detection, need for supplemental testing, color distinction, and breakthrough of non-VRE organisms vary among the chromogenic media tested and may factor into the decision to use a particular medium. PMID:25143571

  16. Comparison of five chromogenic media for recovery of vancomycin-resistant enterococci from fecal samples.

    PubMed

    Suwantarat, Nuntra; Roberts, Ava; Prestridge, Jamie; Seeley, Renee; Speser, Sharon; Harmon, Christopher; Zhang, Chi; Henciak, Susan; Stamper, Paul D; Ross, Tracy; Carroll, Karen C

    2014-11-01

    Five chromogenic agars, evaluated using 400 stool specimens, were found to be superior in sensitivity (range, 89.9 to 93.9%) to bile esculin azide agar with vancomycin (BEAV) agar (84.8%) for detecting vancomycin-resistant enterococci (VRE), and the results were available 24 to 48 h sooner. The time to detection, need for supplemental testing, color distinction, and breakthrough of non-VRE organisms vary among the chromogenic media tested and may factor into the decision to use a particular medium.

  17. Vancomycin-resistant enterococci. The 'superbug' scourge that's coming your way.

    PubMed

    Hagman, H M; Strausbaugh, L J

    1996-05-01

    Strains of vancomycin-resistant enterococci (VRE) have emerged and spread widely throughout the United States during the last few years. Multiply-resistant strains of Enterococcus faecium are especially troublesome because they are often resistant to all commercially available antimicrobial agents. At present, VRE infections occur most often in hospitalized patients with severe underlying disease who have undergone invasive procedures and received prolonged courses of broad-spectrum antimicrobial therapy. Because therapeutic options are limited, prevention of spread from patients with known cases to other vulnerable patients is essential.

  18. Different Genetic Supports for the tet(S) Gene in Enterococci

    PubMed Central

    Freitas, Ana R.; Silveira, Eduarda; Baquero, Fernando; Peixe, Luísa; Roberts, Adam P.; Coque, Teresa M.

    2012-01-01

    The diversity of tet(S) genetic contexts of 13 enterococci from human, animal, and environmental samples from different geographical areas is reported. The tet(S) gene was linked to either CTn6000 variants of chromosomal location or composite platforms flanked by IS1216 located on plasmids (∼40 to 115 kb). The comparative analysis of all tet(S) genetic elements available in the GenBank databases suggests that CTn6000 might be the origin of a variety of tet(S)-carrying platforms that were mobilized to different plasmids. PMID:22908170

  19. High-Level Overview of Data Needs for RE Analysis

    SciTech Connect

    Lopez, Anthony

    2016-12-22

    This presentation provides a high level overview of analysis topics and associated data needs. Types of renewable energy analysis are grouped into two buckets: First, analysis for renewable energy potential, and second, analysis for other goals. Data requirements are similar but and they build upon one another.

  20. High-level manpower movement and Japan's foreign aid.

    PubMed

    Furuya, K

    1992-01-01

    "Japan's technical assistance programs to Asian countries are summarized. Movements of high-level manpower accompanying direct foreign investments by private enterprise are also reviewed. Proposals for increased human resources development include education and training of foreigners in Japan as well as the training of Japanese aid experts and the development of networks for information exchange."

  1. Typewriter Modifications for Persons Who Are High-Level Quadriplegics.

    ERIC Educational Resources Information Center

    O'Reagan, James R.; And Others

    Standard, common electric typewriters are not completely suited to the needs of a high-level quadriplegic typing with a mouthstick. Experiences show that for complete control of a typewriter a mouthstick user needs the combined features of one-button correction, electric forward and reverse indexing, and easy character viewing. To modify a…

  2. Structuring Peer Interaction To Promote High-Level Cognitive Processing.

    ERIC Educational Resources Information Center

    King, Alison

    2002-01-01

    Examines the kind of peer learning that demands high-level cognitive processing, discussing how peer interaction influences cognitive processes (structuring peer interaction and using guided reciprocal peer questioning); how to promote cognitive processing (knowledge construction and integration and socio- cognitive conflict); metacognition; and…

  3. A comparison of high-level waste form characteristics

    SciTech Connect

    Salmon, R.; Notz, K.J.

    1991-01-01

    There are currently about 1055 million curies of high-level waste with a thermal output of about 2950 kilowatts (KW) at four sites in the United States: West Valley Demonstration Project (WVDP), Savannah River Site (SRS), Hanford Site (HANF), and Idaho National Engineering Laboratory (INEL). These quantities are expected to increase to about 1200 million curies and 3570 kw by the end of year 2020. Under the Nuclear Waste Policy Act, this high-level waste must ultimately be disposed of in a geologic repository. Accordingly, canisters of high-level waste immobilized in borosilicate glass or glass-ceramic mixtures are to be produced at the four sites and stored there until a repository becomes available. Data on the estimated production schedules and on the physical, chemical, and radiological characteristics of the canisters of immobilized high-level waste have been collected in OCRWM's Waste Characteristics Data Base, including recent updates an revisions. Comparisons of some of these data for the four sites are presented in this report. 14 refs., 3 tabs.

  4. THE XAL INFRASTRUCTURE FOR HIGH LEVEL CONTROL ROOM APPLICATIONS

    SciTech Connect

    Shishlo, Andrei P; Allen, Christopher K; Chu, Paul; Galambos, John D; Pelaia II, Tom

    2009-01-01

    XAL is a Java programming framework for building high-level control applications related to accelerator physics. The structure, details of implementation, and interaction between components, auxiliary XAL packages, and the latest modifications are discussed. A general overview of XAL applications created for the SNS project is presented.

  5. Effect of pH and Human Serum on the Susceptibility of Group D Streptococci (Enterococci) to Ampicillin In Vitro

    PubMed Central

    Gilbert, D. N.; Eubanks, N.

    1975-01-01

    The in vitro susceptibility of group D streptococci (enterococci) to ampicillin was studied comparing the results obtained in Mueller-Hinton broth (MHB) with those obtained in normal human serum (NHS). The rate of enterococcal killing was consistently faster in NHS than in MHB at equivalent ampicillin concentrations. Whereas an increasing media pH appeared to decrease the susceptibility of enterococci to ampicillin by determinations of the minimum bactericidal concentration (MBC) of ampicillin, an opposite increase in susceptibility was observed when the rate of bactericidal activity was studied. This difference may be explainable by the instability of ampicillin at higher pH values. In both MHB and NHS a paradoxical decrease in the rate and extent of enterococcal killing occurred as the ampicillin concentration was increased above the minimally effective concentration. These results demonstrate the inadequacies of the MBC test system and the need for standardizing test media used for determining the susceptibility of enterococci to ampicillin. PMID:238465

  6. Transport and persistence of tylosin-resistant enterococci, erm genes, and tylosin in soil and drainage water from fields receiving swine manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land application of manure from tylosin-treated swine introduces tylosin-resistant enterococci, erm genes, which confer resistance to tylosin, and tylosin. This study documents the occurrence and transport of tylosin-resistant enterococci, erm genes, and tylosin in tile-drained chisel plow and no-ti...

  7. A comparison of BOX-PCR and pulsed-field gel electrophoresis to determine genetic relatedness of enterococci from different environments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: The genetic relatedness of enterococci from poultry litter to enterococci from nearby surface water and groundwater in the Lower Fraser Valley regions of British Columbia, Canada was determined. Methods and Results: BOX-PCR and Pulsed-Field Gel Electrophoresis (PFGE) were used to subtype en...

  8. High-Level Waste Vitrification Facility Feasibility Study

    SciTech Connect

    D. A. Lopez

    1999-08-01

    A ''Settlement Agreement'' between the Department of Energy and the State of Idaho mandates that all radioactive high-level waste now stored at the Idaho Nuclear Technology and Engineering Center will be treated so that it is ready to be moved out of Idaho for disposal by a compliance date of 2035. This report investigates vitrification treatment of the high-level waste in a High-Level Waste Vitrification Facility based on the assumption that no more New Waste Calcining Facility campaigns will be conducted after June 2000. Under this option, the sodium-bearing waste remaining in the Idaho Nuclear Technology and Engineering Center Tank Farm, and newly generated liquid waste produced between now and the start of 2013, will be processed using a different option, such as a Cesium Ion Exchange Facility. The cesium-saturated waste from this other option will be sent to the Calcine Solids Storage Facilities to be mixed with existing calcine. The calcine and cesium-saturated waste will be processed in the High-Level Waste Vitrification Facility by the end of calendar year 2035. In addition, the High-Level Waste Vitrification Facility will process all newly-generated liquid waste produced between 2013 and the end of 2035. Vitrification of this waste is an acceptable treatment method for complying with the Settlement Agreement. This method involves vitrifying the waste and pouring it into stainless-steel canisters that will be ready for shipment out of Idaho to a disposal facility by 2035. These canisters will be stored at the Idaho National Engineering and Environmental Laboratory until they are sent to a national geologic repository. The operating period for vitrification treatment will be from the end of 2015 through 2035.

  9. Occurrence of Escherichia coli and enterococci in Cladophora (Chlorophyta) in nearshore water and beach sand of Lake Michigan

    USGS Publications Warehouse

    Whitman, Richard L.; Shively, Dawn A.; Pawlik, Heather; Nevers, Meredith; Byappanahalli, Muruleedhara N.

    2003-01-01

    Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density ofEscherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (± standard errors) of 5.3 (± 4.8) and 4.8 (± 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P< 0.001, R2 = 0.73, n = 17) but not in northern beaches (P = 0.892, n = 16). BothE. coli and enterococci survived for over 6 months in sun-dried Cladophora mats stored at 4°C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches.

  10. Occurrence of Escherichia coli and enterococci in Cladophora (Clorophyta) in nearshore water and beach sand of Lake Michigan

    USGS Publications Warehouse

    Whitman, Richard L.; Shively, Dawn A.; Pawlik, Heather; Nevers, Meredith B.; Byappanahalli, Muruleedhara N.

    2003-01-01

    Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density of Escherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (± standard errors) of 5.3 (± 4.8) and 4.8 (± 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P R2 = 0.73, n = 17) but not in northern beaches (P = 0.892, n = 16). Both E. coli and enterococci survived for over 6 months in sun-dried Cladophora mats stored at 4°C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches.

  11. Growth and survival of Escherichia coli and enterococci populations in the macro-alga Cladophora (Chlorophyta)

    USGS Publications Warehouse

    Byappanahalli, M.N.; Shively, D.A.; Nevers, M.B.; Sadowsky, M.J.; Whitman, R.L.

    2003-01-01

    The macro-alga Cladophora glomerata is found in streams and lakes worldwide. High concentrations of Escherichia coli and enterococci have been reported in Cladophora along the Lake Michigan shore. The objective of this study was to determine if Cladophora supported growth of these indicator bacteria. Algal leachate readily supported in vitro multiplication of E. coli and enterococci, suggesting that leachates contain necessary growth-promoting substances. Growth was directly related to the concentration of algal leachate. E. coli survived for over 6 months in dried Cladophora stored at 4°C; residual E. coli grew after mat rehydration, reaching a carrying capacity of 8 log CFU g-1 in 48 h. Results of this study also show that the E. coli strains associated with Cladophora are highly related; in most instances they are genetically different from each other, suggesting that the relationship between E. coli and Cladophora may be casual. These findings indicate that Cladophora provides a suitable environment for indicator bacteria to persist for extended periods and to grow under natural conditions.

  12. Quantification of vancomycin-resistant enterococci and corresponding resistance genes in a sewage treatment plant.

    PubMed

    Furukawa, Takashi; Hashimoto, Reina; Mekata, Tohru

    2015-01-01

    This study aimed to analyze vancomycin-resistant enterococci (VRE) and their resistance genes, vanA and vanB, to examine their presence in sewage treatment systems. Water samples were collected from primary sedimentation tank inlet, aeration tank, final sedimentation tank overflow outlet, and disinfection tank. Enterococcal strains were determined their vancomycin susceptibility by the minimum inhibitory concentration (MIC) test. Vancomycin-resistance genes (vanA and vanB) were quantified by real-time PCR. The sewage treatment process indeed decreased the number of most enterococci contained in the entering sewage, with a removal rate of ≥ 5 log. The MIC test showed that two enterococcal strains resistant to a high concentration of vancomycin (>128 μg mL(-1)). However, most of the enterococcal strains exhibited sensitivity to vancomycin, indicating that VRE were virtually absent in the sewage treatment systems. On the other hand, vancomycin-resistance genes were detected in all the sewage samples, including those collected from the chlorination disinfection tank. The highest copy numbers of vanA (1.5 × 10(3) copies mL(-1)) and vanB (1.0 × 10(3) copies mL(-1)) were detected from the water sample of effluent water and chlorinated water, respectively. Therefore, antibiotic resistance genes remain in the sewage treatment plant and might discharged into water environments such as rivers and coastal areas.

  13. Relationship of human-associated microbial source tracking markers with Enterococci in Gulf of Mexico waters.

    PubMed

    Gordon, Katrina V; Brownell, Miriam; Wang, Shiao Y; Lepo, Joe Eugene; Mott, Joanna; Nathaniel, Rajkumar; Kilgen, Marilyn; Hellein, Kristen N; Kennedy, Elizabeth; Harwood, Valerie J

    2013-03-01

    Human and ecosystem health can be damaged by fecal contamination of recreational waters. Microbial source tracking (MST) can be used to specifically detect domestic sewage containing human waste, thereby informing both risk assessment and remediation strategies. Previously, an inter-laboratory collaboration developed standardized PCR methods for a bacterial, an archaeal, and a viral indicator of human sewage. Here we present results for two subsequent years of field testing in fresh and salt water by five laboratories across the U.S. Gulf Coast (two in Florida and one each in Mississippi, Louisiana and Texas) using common standard operating procedures (SOPs) developed previously. Culturable enterococci were enumerated by membrane filtration, and PCR was used to detect three MST markers targeting domestic sewage: human-associated Bacteroides (HF183), Methanobrevibacter smithii and human polyomaviruses BK and JC (HPyVs). Detection of sewage markers in surface waters was significantly associated with higher enterococci levels and with exceedance of the recreational water quality standard in four or three regions, respectively. Sewage markers were frequently co-detected in single samples, e.g., M. smithii and HF183 were co-detected in 81% of Louisiana samples, and HPyVs and M. smithii were co-detected in over 40% of southwest Florida and Mississippi samples. This study demonstrates the robustness and inter-laboratory transferability of these three markers for the detection of pollution from domestic sewage in the waters impacting the Gulf of Mexico over a coastal range of over 1000 miles.

  14. Antimicrobial resistance in Campylobacter spp., Escherichia coli and enterococci associated with pigs in Australia.

    PubMed

    Hart, W S; Heuzenroeder, M W; Barton, M D

    2004-06-01

    The major influences on the amplification and spread of antibiotic-resistant bacteria are the therapeutic use of antibiotics in human medicine and their use in livestock for therapy, prophylaxis and growth promotion. The use of veterinary antibiotics has many benefits to the livestock industries ensuring animal health and welfare, but use at subtherapeutic levels also exerts great selective pressure on emergence of resistant bacteria. The possible effect on human health is a problem of current debate. This study involved sampling pig carcasses, pig meat and assessing the level of resistance in zoonotic enteric bacteria of concern to human health. In South Australian pigs, thermophilic Campylobacter species showed widespread resistance (60-100%) to tylosin, erythromycin, lincomycin, ampicillin and tetracycline. No resistance was seen to ciprofloxacin. The enterococci demonstrated little resistance (0-30%) to vancomycin or virginiamycin, but the overall results from the antibiotic sensitivity testing of the enterococci have demonstrated how widespread their resistance has become. Escherichia coli strains showed widespread resistance to tetracycline and moderately common resistance (30-60%) to ampicillin and sulphadiazine. Resistance to more than one antibiotic was common. Pigs from New South Wales were also sampled and differences in resistance patterns were noted, perhaps reflecting different antibiotic use regimens in that state.

  15. Enterococci from Tolminc cheese: population structure, antibiotic susceptibility and incidence of virulence determinants.

    PubMed

    Canzek Majhenic, Andreja; Rogelj, Irena; Perko, Bogdan

    2005-07-15

    Microbiological analysis of ripened artisanal Tolminc cheese revealed the presence of an enterococcal population in numbers of up to 10(6) per g. All colonies, isolated from the citrate azide tween carbonate (CATC) enterococcal selective medium were Gram positive and coccal-shaped and were analysed with PhenePlate FS system. This system discriminated 10 PhP clusters among the 90 enterococcal isolates. From each cluster the most representative isolate for that particular type was selected for further study. The 10 representative enterococci were catalase negative and grew in the presence of NaCl (2%, 4% and 6.5%) and bile salts (0.06%). Genus specific primers confirmed all 10 enterococcal representatives as Enterococcus members, while species specific primers determined them further as strains of Enterococcus faecalis species. PCR for vanA and vanB genes detection, respectively, amplified no PCR products. The absence of van genes was confirmed with both disc and E-test, as isolates were susceptible to vancomycin according to the National Committee for Clinical Laboratory Standards (NCCLS). The results of disc tests with other antimicrobial agents (ampicillin, vancomycin, kanamycin, penicillin, erythromycin, neomycin, chloramphenicol, clindamycin, rifampin) did not differ much among the tested enterococci: they were all very resistant to clindamycin only. The incidence of enterococcus virulence determinants was as expected: all of the 10 E. faecalis strains tested possessed multiple determinants (between 7 and 11).

  16. Multi-laboratory survey of qPCR enterococci analysis method performance

    EPA Pesticide Factsheets

    Quantitative polymerase chain reaction (qPCR) has become a frequently used technique for quantifying enterococci in recreational surface waters, but there are several methodological options. Here we evaluated how three method permutations, type of mastermix, sample extract dilution and use of controls in results calculation, affect method reliability among multiple laboratories with respect to sample interference. Multiple samples from each of 22 sites representing an array of habitat types were analyzed using EPA Method 1611 and 1609 reagents with full strength and five-fold diluted extracts. The presence of interference was assessed three ways: using sample processing and PCR amplifications controls; consistency of results across extract dilutions; and relative recovery of target genes from spiked enterococci in water sample compared to control matrices with acceptable recovery defined as 50 to 200%. Method 1609, which is based on an environmental mastermix, was found to be superior to Method 1611, which is based on a universal mastermix. Method 1611 had over a 40% control assay failure rate with undiluted extracts and a 6% failure rate with diluted extracts. Method 1609 failed in only 11% and 3% of undiluted and diluted extracts analyses. Use of sample processing control assay results in the delta-delta Ct method for calculating relative target gene recoveries increased the number of acceptable recovery results. Delta-delta tended to bias recoveries fr

  17. Antibiotic resistance and adhesion properties of oral Enterococci associated to dental caries

    PubMed Central

    2011-01-01

    Background Enterococci are increasingly associated with opportunistic infections in Humans but the role of the oral cavity as a reservoir for this species is unclear. This study aimed to explore the carriage rate of Enterococci in the oral cavity of Tunisian children and their antimicrobial susceptibility to a broad range of antibiotics together with their adherence ability to abiotic and biotic surfaces. Results In this study, 17 E. faecalis (27.5%) and 4 E. faecium (6.5%) were detected. The identified strains showed resistance to commonly used antibiotics. Among the 17 isolated E. faecalis, 12 strains (71%) were slime producers and 5 strains were non-producers. Among the 4 E. faecium, 2 strains were slime producers. All the tested strains were able to adhere to at least one of the two tested cell lines. Our result showed that 11 E. faecalis and 2 E. faecium strains adhered strongly to Hep-2 as well as to A549 cells. Conclusions Drugs resistance and strong biofilm production abilities together with a high phenotypic adhesion to host cells are important equipment in E. faecalis and E. faecium which lead to their oral cavity colonization and focal infections. PMID:21714920

  18. Chemical trapping of vancomycin: a potential strategy for preventing selection of vancomycin-resistant Enterococci.

    PubMed

    Horwitz, Ehud; Tal-Gan, Yftah; Temper, Violetta; Shapiro, Mervyn; Gilon, Chaim; Hoffman, Amnon

    2012-04-01

    Emergence of antimicrobial resistance is among the most worrisome issues in public health worldwide. Vancomycin resistance is rapidly spreading, resulting in increased morbidity, mortality, and healthcare-associated costs. Multiple strategies are required to preserve the effectiveness of this essential antibiotic. It has been recently shown that biliary excretion of vancomycin following parenteral administration results in significant fecal concentrations of vancomycin that may lead to selection of vancomycin-resistant strains within the colon. In this study we present a novel strategy for preventing this undesired effect and its consequences, using chemical trapping of vancomycin by a tripeptide analog that mimics the natural bacterial vancomycin binding-site. Initially, we demonstrated that a tripeptide analog can neutralize vancomycin activity against Enterococci at a molar excess of 28. In the second phase, two chemical modifications, designed to attach the tripeptide to vancomycin covalently, were explored. Attachment of a 4-flurosulfonyl-benzoic acid (FSBA) moiety to the parent tripeptide resulted in vancomycin neutralization at a molar ratio of less than 4:1. Finally it was shown that the FSBA-bound tripeptide analog can prevent in-vitro selection of vancomycin-resistant Enterococci (VRE) from a mixed vancomycin susceptible/resistant population following exposure to vancomycin. These findings demonstrate the ability of the proposed strategy to prevent selection of VRE. The present proof-of-concept study provides the basis for further development of the proposed strategy. Further, this strategy may be implemented for combating resistance to other antimicrobials.

  19. Synergistic effect of [10]-gingerol and aminoglycosides against vancomycin-resistant enterococci (VRE).

    PubMed

    Nagoshi, Chihiro; Shiota, Sumiko; Kuroda, Teruo; Hatano, Tsutomu; Yoshida, Takashi; Kariyama, Reiko; Tsuchiya, Tomofusa

    2006-03-01

    An extract from ginger (root of Zingiber officinale) reduced the minimum inhibitory concentrations (MICs) of aminoglycosides in vancomycin-resistant enterococci (VRE). The effective compound was isolated and identified as [10]-gingerol. In the presence of [10]-gingerol at 1/10 concentration of its own MIC, the MIC of arbekacin was lowered by 1/32 to 1/16. [10]-Gingerol also reduced the MICs of other aminoglycosides, and of bacitracin and polymixin B, but not of other antimicrobial agents tested. Because [10]-gingerol reduced the MICs of several aminoglycosides both in strains possessing or lacking aminoglycoside-modification enzymes, it seems that the effect of [10]-gingerol is not related to these enzymes, which mainly confer bacterial resistance against aminoglycosides. It seemed that a detergent-like effect of [10]-gingerol potentiated the antimicrobial activity of the aminoglycosides. In fact, some detergents such as sodium dodecyl sulfate (SDS) and Triton X-100 reduced the MICs of aminoglycosides, bacitracin and polymixin B in VRE. Since the intrinsic resistance to aminoglycosides in enterococci is due to low level of entry of the drugs into the cells, increase in the membrane permeability caused by [10]-gingerol will enhance the influx of aminoglycosides into enterococcal cells.

  20. Characterization of fecal vancomycin-resistant enterococci with acquired and intrinsic resistance mechanisms in wild animals, Spain.

    PubMed

    Lozano, Carmen; Gonzalez-Barrio, David; Camacho, Maria Cruz; Lima-Barbero, Jose Francisco; de la Puente, Javier; Höfle, Ursula; Torres, Carmen

    2016-11-01

    The objectives were to evaluate the presence of vancomycin-resistant enterococci with acquired (VRE-a) and intrinsic (VRE-i) resistance mechanisms in fecal samples from different wild animals, and analyze their phenotypes and genotypes of antimicrobial resistance. A total of 348 cloacal/rectal samples from red-legged partridges (127), white storks (81), red kites (59), and wild boars (81) (June 2014/February 2015) were inoculated in Slanetz-Bartley agar supplemented with vancomycin (4 μg/mL). We investigated the susceptibility to 12 antimicrobials and the presence of 19 antimicrobial resistance and five virulence genes. In addition, we performed multilocus sequence typing, detection of IS16 and studied Tn1546 structure. One VRE-a isolate was identified in one wild boar. This isolate was identified as Enterococcus faecium, harbored vanA gene included into Tn1546 (truncated with IS1542/IS1216), and belonged to the new ST993. This isolate contained the erm(A), erm(B), tet(M), dfrG, and dfrK genes. Neither element IS16 nor the studied virulence genes were detected. Ninety-six VRE-i isolates were identified (89 Enterococcus gallinarum and seven Enterococcus casseliflavus), with the following prevalence: red kites (71.2 %), white storks (46.9 %), red-legged partridges (7.9 %), and wild boars (4.9 %). Most E. gallinarum isolates showed resistance to tetracycline (66.3 %) and/or erythromycin (46.1 %). High-level resistance to aminoglycosides was present among our VRE-i isolates: kanamycin (22.9 %), streptomycin (11.5 %), and gentamicin (9.4 %). In general, VRE-i isolates of red kites showed higher rates of resistance for non-glycopeptide agents than those of other animal species. The dissemination of acquired resistance mechanisms in natural environments could have implications in the global spread of resistance with public health implications.

  1. Multipurpose optimization models for high level waste vitrification

    SciTech Connect

    Hoza, M.

    1994-08-01

    Optimal Waste Loading (OWL) models have been developed as multipurpose tools for high-level waste studies for the Tank Waste Remediation Program at Hanford. Using nonlinear programming techniques, these models maximize the waste loading of the vitrified waste and optimize the glass formers composition such that the glass produced has the appropriate properties within the melter, and the resultant vitrified waste form meets the requirements for disposal. The OWL model can be used for a single waste stream or for blended streams. The models can determine optimal continuous blends or optimal discrete blends of a number of different wastes. The OWL models have been used to identify the most restrictive constraints, to evaluate prospective waste pretreatment methods, to formulate and evaluate blending strategies, and to determine the impacts of variability in the wastes. The OWL models will be used to aid in the design of frits and the maximize the waste in the glass for High-Level Waste (HLW) vitrification.

  2. RETENTION OF SULFATE IN HIGH LEVEL RADIOACTIVE WASTE GLASS

    SciTech Connect

    Fox, K.

    2010-09-07

    High level radioactive wastes are being vitrified at the Savannah River Site for long term disposal. Many of the wastes contain sulfate at concentrations that can be difficult to retain in borosilicate glass. This study involves efforts to optimize the composition of a glass frit for combination with the waste to improve sulfate retention while meeting other process and product performance constraints. The fabrication and characterization of several series of simulated waste glasses are described. The experiments are detailed chronologically, to provide insight into part of the engineering studies used in developing frit compositions for an operating high level waste vitrification facility. The results lead to the recommendation of a specific frit composition and a concentration limit for sulfate in the glass for the next batch of sludge to be processed at Savannah River.

  3. Management of data quality of high level waste characterization

    SciTech Connect

    Winters, W.I., Westinghouse Hanford

    1996-06-12

    Over the past 10 years, the Hanford Site has been transitioning from nuclear materials production to Site cleanup operations. High-level waste characterization at the Hanford Site provides data to support present waste processing operations, tank safety programs, and future waste disposal programs. Quality elements in the high-level waste characterization program will be presented by following a sample through the data quality objective, sampling, laboratory analysis and data review process. Transition from production to cleanup has resulted in changes in quality systems and program; the changes, as well as other issues in these quality programs, will be described. Laboratory assessment through quality control and performance evaluation programs will be described, and data assessments in the laboratory and final reporting in the tank characterization reports will be discussed.

  4. Life Extension of Aging High Level Waste (HLW) Tanks

    SciTech Connect

    BRYSON, D.

    2002-02-04

    The Double Shell Tanks (DSTs) play a critical role in the Hanford High-Level Waste Treatment Complex, and therefore activities are underway to protect and better understand these tanks. The DST Life Extension Program is focused on both tank life extension and on evaluation of tank integrity. Tank life extension activities focus on understanding tank failure modes and have produced key chemistry and operations controls to minimize tank corrosion and extend useful tank life. Tank integrity program activities have developed and applied key technologies to evaluate the condition of the tank structure and predict useful tank life. Program results to date indicate that DST useful life can be extended well beyond the original design life and allow the existing tanks to fill a critical function within the Hanford High-Level Waste Treatment Complex. In addition the tank life may now be more reliably predicted, facilitating improved planning for the use and possible future replacement of these tanks.

  5. Long-term high-level waste technology

    NASA Astrophysics Data System (ADS)

    Cornman, W. R.

    1980-07-01

    This series of reports summarizes research and development studies on the immobilization of high level wastes from the chemical reprocessing of nuclear reactor fuels. Immobilization of the wastes (defense and commercial) consists of placing them in a high integrity form with a very low potential for radionuclide release. Immobilization of commercial wastes is being considered on a contingency basis in the event that reprocessing is resumed. The basic plan for meeting the goal of immobilization of the DOE high level wastes is: (1) to develop technology to support a realistic choice of waste form alternatives for each of the three DOE sites; (2) to develop product and processing technology with sufficient scaleup to provide design data for full scale facilities; and (3) to construct and operate the facilities.

  6. Mixing Processes in High-Level Waste Tanks - Final Report

    SciTech Connect

    Peterson, P.F.

    1999-05-24

    The mixing processes in large, complex enclosures using one-dimensional differential equations, with transport in free and wall jets is modeled using standard integral techniques. With this goal in mind, we have constructed a simple, computationally efficient numerical tool, the Berkeley Mechanistic Mixing Model, which can be used to predict the transient evolution of fuel and oxygen concentrations in DOE high-level waste tanks following loss of ventilation, and validate the model against a series of experiments.

  7. Hierarchical High Level Information Fusion (H2LIFT)

    DTIC Science & Technology

    2008-09-15

    National Strategy for Maritime Security‖, 2005. 11. J. Morgan and B. Wimmer, ― Enhancing Awareness in the Maritime Domain‖, CHIPS Magazine, 14-15, 2005...Intelligence, vol. 18, no. 3, pp. 475–496, 2004. 30. K. Sambhoos, et al., ― Enhancements to high level data fusion using graph matching and state space search...range and bearing calculations over long distances. Loran -C and GPS navigation receivers use ellipsoidal earth models to compute position and waypoint

  8. Automatic rule generation for high-level vision

    NASA Technical Reports Server (NTRS)

    Rhee, Frank Chung-Hoon; Krishnapuram, Raghu

    1992-01-01

    Many high-level vision systems use rule-based approaches to solving problems such as autonomous navigation and image understanding. The rules are usually elaborated by experts. However, this procedure may be rather tedious. In this paper, we propose a method to generate such rules automatically from training data. The proposed method is also capable of filtering out irrelevant features and criteria from the rules.

  9. Trustworthy System Development Through High-Level Synthesis

    DTIC Science & Technology

    2014-09-01

    processor manufacturers have embraced the high-level synthesis ( HLS ) design philosophy. HLS offers the potential to explore the design space of electronic...circuits and systems more efficiently than traditional methods. In this thesis, we investigate the ap- plication of HLS to hardware-oriented security and...level synthesis ( HLS ) design phi- losophy. HLS offers the potential to explore the design space of electronic circuits and systems more efficiently than

  10. Case for retrievable high-level nuclear waste disposal

    USGS Publications Warehouse

    Roseboom, Eugene H.

    1994-01-01

    Plans for the nation's first high-level nuclear waste repository have called for permanently closing and sealing the repository soon after it is filled. However, the hydrologic environment of the proposed site at Yucca Mountain, Nevada, should allow the repository to be kept open and the waste retrievable indefinitely. This would allow direct monitoring of the repository and maintain the options for future generations to improve upon the disposal methods or use the uranium in the spent fuel as an energy resource.

  11. The tracking of high level waste shipments-TRANSCOM system

    SciTech Connect

    Johnson, P.E.; Joy, D.S.; Pope, R.B.

    1995-12-31

    The TRANSCOM (transportation tracking and communication) system is the U.S. Department of Energy`s (DOE`s) real-time system for tracking shipments of spent fuel, high-level wastes, and other high-visibility shipments of radioactive material. The TRANSCOM system has been operational since 1988. The system was used during FY1993 to track almost 100 shipments within the US.DOE complex, and it is accessed weekly by 10 to 20 users.

  12. Handbook of high-level radioactive waste transportation

    SciTech Connect

    Sattler, L.R.

    1992-10-01

    The High-Level Radioactive Waste Transportation Handbook serves as a reference to which state officials and members of the general public may turn for information on radioactive waste transportation and on the federal government`s system for transporting this waste under the Civilian Radioactive Waste Management Program. The Handbook condenses and updates information contained in the Midwestern High-Level Radioactive Waste Transportation Primer. It is intended primarily to assist legislators who, in the future, may be called upon to enact legislation pertaining to the transportation of radioactive waste through their jurisdictions. The Handbook is divided into two sections. The first section places the federal government`s program for transporting radioactive waste in context. It provides background information on nuclear waste production in the United States and traces the emergence of federal policy for disposing of radioactive waste. The second section covers the history of radioactive waste transportation; summarizes major pieces of legislation pertaining to the transportation of radioactive waste; and provides an overview of the radioactive waste transportation program developed by the US Department of Energy (DOE). To supplement this information, a summary of pertinent federal and state legislation and a glossary of terms are included as appendices, as is a list of publications produced by the Midwestern Office of The Council of State Governments (CSG-MW) as part of the Midwestern High-Level Radioactive Waste Transportation Project.

  13. Materials Science of High-Level Nuclear Waste Immobilization

    SciTech Connect

    Weber, William J.; Navrotsky, Alexandra; Stefanovsky, S. V.; Vance, E. R.; Vernaz, Etienne Y.

    2009-01-09

    With the increasing demand for the development of more nuclear power comes the responsibility to address the technical challenges of immobilizing high-level nuclear wastes in stable solid forms for interim storage or disposition in geologic repositories. The immobilization of high-level nuclear wastes has been an active area of research and development for over 50 years. Borosilicate glasses and complex ceramic composites have been developed to meet many technical challenges and current needs, although regulatory issues, which vary widely from country to country, have yet to be resolved. Cooperative international programs to develop advanced proliferation-resistant nuclear technologies to close the nuclear fuel cycle and increase the efficiency of nuclear energy production might create new separation waste streams that could demand new concepts and materials for nuclear waste immobilization. This article reviews the current state-of-the-art understanding regarding the materials science of glasses and ceramics for the immobilization of high-level nuclear waste and excess nuclear materials and discusses approaches to address new waste streams.

  14. High level cognitive information processing in neural networks

    NASA Technical Reports Server (NTRS)

    Barnden, John A.; Fields, Christopher A.

    1992-01-01

    Two related research efforts were addressed: (1) high-level connectionist cognitive modeling; and (2) local neural circuit modeling. The goals of the first effort were to develop connectionist models of high-level cognitive processes such as problem solving or natural language understanding, and to understand the computational requirements of such models. The goals of the second effort were to develop biologically-realistic model of local neural circuits, and to understand the computational behavior of such models. In keeping with the nature of NASA's Innovative Research Program, all the work conducted under the grant was highly innovative. For instance, the following ideas, all summarized, are contributions to the study of connectionist/neural networks: (1) the temporal-winner-take-all, relative-position encoding, and pattern-similarity association techniques; (2) the importation of logical combinators into connection; (3) the use of analogy-based reasoning as a bridge across the gap between the traditional symbolic paradigm and the connectionist paradigm; and (4) the application of connectionism to the domain of belief representation/reasoning. The work on local neural circuit modeling also departs significantly from the work of related researchers. In particular, its concentration on low-level neural phenomena that could support high-level cognitive processing is unusual within the area of biological local circuit modeling, and also serves to expand the horizons of the artificial neural net field.

  15. Analysis of Enterococci and Bacteriodales Fecal Indicator Bacteria in a Lake Michigan Tributary by Real-Time Quantitative PCR

    EPA Science Inventory

    The Salt Creek watershed in northwest Indiana drains into Lake Michigan near several heavily used recreational beaches. This study aimed to investigate the levels of fecal indicator bacteria, enterococci and Bacteroidales, in Salt Creek using real-time quantitative PCR (qPCR) an...

  16. Prevalence of antimicrobial resistance in faecal enterococci from vet-visiting pets and assessment of risk factors.

    PubMed

    Leite-Martins, L; Mahú, M I; Costa, A L; Bessa, L J; Vaz-Pires, P; Loureiro, L; Niza-Ribeiro, J; de Matos, A J F; Martins da Costa, P

    2015-06-27

    The objective of this study was to determine the prevalence of antimicrobial resistance (AMR) exhibited by enterococci isolated from faeces of pets and its underlying risk factors. From September 2009 to May 2012, rectal swabs were collected from 74 dogs and 17 cats, selected from the population of animals visiting the Veterinary Hospital of University of Porto, UPVet, through a systematic random procedure. Animal owners answered a questionnaire about the risk factors that could influence the presence of AMR in faecal enterococci. Enterococci isolation, identification and antimicrobial (AM) susceptibility testing were performed. Data analyses of multilevel, univariable and multivariable generalised linear mixed models were conducted. From all enterococci isolated (n=315), 61 per cent were considered multidrug-resistant, whereas only 9.2 per cent were susceptible to all AMs tested. Highest resistance was found to tetracycline (67.0 per cent), rifampicin (60.3 per cent), azithromycin (58.4 per cent), quinupristin/dalfopristin (54.0 per cent) and erythromycin (53.0 per cent). Previous fluoroquinolone treatments and coprophagic habits were the features more consistently associated with the presence of AMR for three (chloramphenicol, ciprofloxacin and azithromycin) and seven (tetracycline, rifampicin, gentamicin, chloramphenicol, ciprofloxacin, erythromycin and azithromycin), respectively, out of nine AMs assessed. Evaluating risk factors that determine the presence of drug-resistant bacteria in pets, a possible source of resistance determinants to human beings, is crucial for the selection of appropriate treatment guidelines by veterinary practitioners.

  17. COMPARISON OF MENTEROCOCCUS AGAR AND THE U.S. ENVIRONMENTAL PROTECTION AGENCY-RECOMENDED ENTEROCOCCI METHODS, ME AND MEI AGAR

    EPA Science Inventory

    To maintain waters that are "fishable and swimmable", mandated by the Clean Water Act, the U.S. Environmental Protection Agency (EPA) is developing a list of approved methods for use in enumerating enterococci and E. coli in ambient waters. As part of this effort, we compared mEn...

  18. Diversity and antibiotic susceptibility of autochthonous dairy enterococci isolates: are they safe candidates for autochthonous starter cultures?

    PubMed Central

    Terzić-Vidojević, Amarela; Veljović, Katarina; Begović, Jelena; Filipić, Brankica; Popović, Dušanka; Tolinački, Maja; Miljković, Marija; Kojić, Milan; Golić, Nataša

    2015-01-01

    Enterococci represent the most controversial group of dairy bacteria. They are found to be the main constituent of many traditional Mediterranean dairy products and contribute to their characteristic taste and flavor. On the other hand, during the last 50 years antibiotic-resistant enterococci have emerged as leading causes of nosocomial infections worldwide. The aim of this study was to determine the diversity, technological properties, antibiotic susceptibility and virulence traits of 636 enterococci previously isolated from 55 artisan dairy products from 12 locations in the Western Balkan countries (WBC) of Serbia, Croatia and Bosnia and Herzegovina. All strains were identified both by microbiological and molecular methods. The predominant species was Enterococcus durans, followed by Enterococcus faecalis and Enterococcus faecium. Over 44% of the isolates were resistant to ciprofloxacin and erythromycin, while 26.2% of the isolates were multi-resistant to three or more antibiotics belonging to different families. 185 isolates (29.1%) were susceptible to all 13 of the antibiotics tested. The antibiotic-susceptible isolates were further tested for possible virulence genes and the production of biogenic amines. Finally, five enterococci isolates were found to be antibiotic susceptible with good technological characteristics and without virulence traits or the ability to produce biogenic amines, making them possible candidates for biotechnological application as starter cultures in the dairy industry. PMID:26441888

  19. Rapid detection of Escherichia coli and enterococci in recreational water using an immunomagnetic separation/adenosine triphosphate technique

    USGS Publications Warehouse

    Bushon, R.N.; Brady, A.M.; Likirdopulos, C.A.; Cireddu, J.V.

    2009-01-01

    Aims: The aim of this study was to examine a rapid method for detecting Escherichia coli and enterococci in recreational water. Methods and Results: Water samples were assayed for E. coli and enterococci by traditional and immunomagnetic separation/adenosine triphosphate (IMS/ATP) methods. Three sample treatments were evaluated for the IMS/ATP method: double filtration, single filtration, and direct analysis. Pearson's correlation analysis showed strong, significant, linear relations between IMS/ATP and traditional methods for all sample treatments; strongest linear correlations were with the direct analysis (r = 0.62 and 0.77 for E. coli and enterococci, respectively). Additionally, simple linear regression was used to estimate bacteria concentrations as a function of IMS/ATP results. The correct classification of water-quality criteria was 67% for E. coli and 80% for enterococci. Conclusions: The IMS/ATP method is a viable alternative to traditional methods for faecal-indicator bacteria. Significance and Impact of the Study: The IMS/ATP method addresses critical public health needs for the rapid detection of faecal-indicator contamination and has potential for satisfying US legislative mandates requiring methods to detect bathing water contamination in 2 h or less. Moreover, IMS/ATP equipment is considerably less costly and more portable than that for molecular methods, making the method suitable for field applications. ?? 2009 The Authors.

  20. Development of a High Level Waste Tank Inspection System

    SciTech Connect

    Appel, D.K.; Loibl, M.W.; Meese, D.C.

    1995-03-21

    The Westinghouse Savannah River Technology Center was requested by it`s sister site, West Valley Nuclear Service (WVNS), to develop a remote inspection system to gather wall thickness readings of their High Level Waste Tanks. WVNS management chose to take a proactive approach to gain current information on two tanks t hat had been in service since the early 70`s. The tanks contain high level waste, are buried underground, and have only two access ports to an annular space between the tank and the secondary concrete vault. A specialized remote system was proposed to provide both a visual surveillance and ultrasonic thickness measurements of the tank walls. A magnetic wheeled crawler was the basis for the remote delivery system integrated with an off-the-shelf Ultrasonic Data Acquisition System. A development program was initiated for Savannah River Technology Center (SRTC) to design, fabricate, and test a remote system based on the Crawler. The system was completed and involved three crawlers to perform the needed tasks, an Ultrasonic Crawler, a Camera Crawler, and a Surface Prep Crawler. The crawlers were computer controlled so that their operation could be done remotely and their position on the wall could be tracked. The Ultrasonic Crawler controls were interfaced with ABB Amdata`s I-PC, Ultrasonic Data Acquisition System so that thickness mapping of the wall could be obtained. A second system was requested by Westinghouse Savannah River Company (WSRC), to perform just ultrasonic mapping on their similar Waste Storage Tanks; however, the system needed to be interfaced with the P-scan Ultrasonic Data Acquisition System. Both remote inspection systems were completed 9/94. Qualifications tests were conducted by WVNS prior to implementation on the actual tank and tank development was achieved 10/94. The second inspection system was deployed at WSRC 11/94 with success, and the system is now in continuous service inspecting the remaining high level waste tanks at WSRC.

  1. High-level waste management technology program plan

    SciTech Connect

    Harmon, H.D.

    1995-01-01

    The purpose of this plan is to document the integrated technology program plan for the Savannah River Site (SRS) High-Level Waste (HLW) Management System. The mission of the SRS HLW System is to receive and store SRS high-level wastes in a see and environmentally sound, and to convert these wastes into forms suitable for final disposal. These final disposal forms are borosilicate glass to be sent to the Federal Repository, Saltstone grout to be disposed of on site, and treated waste water to be released to the environment via a permitted outfall. Thus, the technology development activities described herein are those activities required to enable successful accomplishment of this mission. The technology program is based on specific needs of the SRS HLW System and organized following the systems engineering level 3 functions. Technology needs for each level 3 function are listed as reference, enhancements, and alternatives. Finally, FY-95 funding, deliverables, and schedules are s in Chapter IV with details on the specific tasks that are funded in FY-95 provided in Appendix A. The information in this report represents the vision of activities as defined at the beginning of the fiscal year. Depending on emergent issues, funding changes, and other factors, programs and milestones may be adjusted during the fiscal year. The FY-95 SRS HLW technology program strongly emphasizes startup support for the Defense Waste Processing Facility and In-Tank Precipitation. Closure of technical issues associated with these operations has been given highest priority. Consequently, efforts on longer term enhancements and alternatives are receiving minimal funding. However, High-Level Waste Management is committed to participation in the national Radioactive Waste Tank Remediation Technology Focus Area. 4 refs., 5 figs., 9 tabs.

  2. Defense High Level Waste Disposal Container System Description Document

    SciTech Connect

    N. E. Pettit

    2001-07-13

    The Defense High Level Waste Disposal Container System supports the confinement and isolation of waste within the Engineered Barrier System of the Monitored Geologic Repository (MGR). Disposal containers are loaded and sealed in the surface waste handling facilities, transferred to the underground through the accesses using a rail mounted transporter, and emplaced in emplacement drifts. The defense high level waste (HLW) disposal container provides long-term confinement of the commercial HLW and defense HLW (including immobilized plutonium waste forms [IPWF]) placed within disposable canisters, and withstands the loading, transfer, emplacement, and retrieval loads and environments. US Department of Energy (DOE)-owned spent nuclear fuel (SNF) in disposable canisters may also be placed in a defense HLW disposal container along with commercial HLW waste forms, which is known as co-disposal. The Defense High Level Waste Disposal Container System provides containment of waste for a designated period of time, and limits radionuclide release. The disposal container/waste package maintains the waste in a designated configuration, withstands maximum handling and rockfall loads, limits the individual canister temperatures after emplacement, resists corrosion in the expected handling and repository environments, and provides containment of waste in the event of an accident. Defense HLW disposal containers for HLW disposal will hold up to five HLW canisters. Defense HLW disposal containers for co-disposal will hold up to five HLW canisters arranged in a ring and one DOE SNF canister inserted in the center and/or one or more DOE SNF canisters displacing a HLW canister in the ring. Defense HLW disposal containers also will hold two Multi-Canister Overpacks (MCOs) and two HLW canisters in one disposal container. The disposal container will include outer and inner cylinders, outer and inner cylinder lids, and may include a canister guide. An exterior label will provide a means by

  3. Efficacy of hand disinfectants against vancomycin-resistant enterococci in vitro.

    PubMed

    Kampf, G; Höfer, M; Wendt, C

    1999-06-01

    Vancomycin-resistant enterococci (VRE) may be spread within a hospital via the contaminated hands of the healthcare worker. Effective hand disinfectants are necessary to break chains of transmission. We determined the bactericidal activity of 1-propanol, chlorhexidine digluconate (0.5 and 4%). Sterillium (45% 2-propanol, 30% 1-propanol and 0.2% mecetronium etilsulphate), Skinsept F (70% 2-propanol, 0.5% chlorhexidine digluconate and 0.45% hydrogen peroxide) and Hibisol (70% 2-propanol and 0.5% chlorhexidine gluconate) against 11 clonally distinct enterococcal isolates in a quantitative suspension test. Four isolates were vancomycin susceptible, four were vanA and the remainder vanB positive. Eight isolates were identified as Enterococcus faecium, two as Enterococcus faecalis and one as Enterococcus gallinarum. The investigator was blinded to the species and the genotype. Four parallel experiments were carried out for each isolate, each preparation, each dilution and each reaction time. 1-Propanol (60%), Sterillium, Skinsept F and Hibisol were all highly bactericidal after 15 and 30 s against VRE and vancomycin-susceptible enterococci (VSE) with reduction factors (RF) > 6.4, even in dilution of 50% (v/v). No significant difference was observed between vanA isolates, vanB isolates and VSE. Chlorhexidine digluconate (0.5% and 4%) was found to be less bactericidal after 30, 60 and 300 sec (RF < or = 2.5). The vanB genotype isolates were found to be significantly more susceptible to chlorhexidine (0.5%) than the vanA isolates (60 sec; one-way ANOVA model; P = 0.05). After 300 sec the vanB genotype isolates were found to be significantly more susceptible to chlorhexidine (0.5%) than the other two genotype isolates (P = 0.016). The vanA isolates were found to be significantly more susceptible to chlorhexidine (4%) than the vanB isolates (300 s; P = 0.024). E. faecium was found to be less susceptible to chlorhexidine than E. faecalis at all concentrations and reaction

  4. High-level neutron coincidence counter maintenance manual

    SciTech Connect

    Swansen, J.; Collinsworth, P.

    1983-05-01

    High-level neutron coincidence counter operational (field) calibration and usage is well known. This manual makes explicit basic (shop) check-out, calibration, and testing of new units and is a guide for repair of failed in-service units. Operational criteria for the major electronic functions are detailed, as are adjustments and calibration procedures, and recurrent mechanical/electromechanical problems are addressed. Some system tests are included for quality assurance. Data on nonstandard large-scale integrated (circuit) components and a schematic set are also included.

  5. Market Designs for High Levels of Variable Generation: Preprint

    SciTech Connect

    Milligan, M.; Holttinen, H.; Kiviluoma, J.; Orths, A.; Lynch, M.; Soder, L.

    2014-10-01

    Variable renewable generation is increasing in penetration in modern power systems, leading to higher variability in the supply and price of electricity as well as lower average spot prices. This raises new challenges, particularly in ensuring sufficient capacity and flexibility from conventional technologies. Because the fixed costs and lifetimes of electricity generation investments are significant, designing markets and regulations that ensure the efficient integration of renewable generation is a significant challenge. This papers reviews the state of play of market designs for high levels of variable generation in the United States and Europe and considers new developments in both regions.

  6. Modern Alchemy: Solidifying high-level nuclear waste

    SciTech Connect

    Newton, C.C.

    1997-07-01

    The U.S. Department of Energy is putting a modern version of alchemy to work to produce an answer to a decades-old problem. It is taking place at the Savannah River Site (SRS) in Aiken, South Carolina and at the West Valley Demonstration Project (WVDP) near Buffalo, New York. At both locations, contractor Westinghouse Electric Corporation is applying technology that is turning liquid high-level radioactive waste (HLW) into a stabilized, durable glass for safer and easier management. The process is called vitrification. SRS and WVDP are now operating the nation`s first full-scale HLW vitrification plants.

  7. Corrosion and failure processes in high-level waste tanks

    SciTech Connect

    Mahidhara, R.K.; Elleman, T.S.; Murty, K.L.

    1992-11-01

    A large amount of radioactive waste has been stored safely at the Savannah River and Hanford sites over the past 46 years. The aim of this report is to review the experimental corrosion studies at Savannah River and Hanford with the intention of identifying the types and rates of corrosion encountered and indicate how these data contribute to tank failure predictions. The compositions of the High-Level Wastes, mild steels used in the construction of the waste tanks and degradation-modes particularly stress corrosion cracking and pitting are discussed. Current concerns at the Hanford Site are highlighted.

  8. High-level wastes: DOE names three sites for characterization

    SciTech Connect

    1986-07-01

    DOE announced in May 1986 that there will be there site characterization studies made to determine suitability for a high-level radioactive waste repository. The studies will include several test drillings to the proposed disposal depths. Yucca Mountain, Nevada; Deaf Smith Country, Texas, and Hanford, Washington were identified as the study sites, and further studies for a second repository site in the East were postponed. The affected states all filed suits in federal circuit courts because they were given no advance warning of the announcement of their selection or the decision to suspend work on a second repository. Criticisms of the selection process include the narrowing or DOE options.

  9. Burning high-level TRU waste in fusion fission reactors

    NASA Astrophysics Data System (ADS)

    Shen, Yaosong

    2016-09-01

    Recently, the concept of actinide burning instead of a once-through fuel cycle for disposing spent nuclear fuel seems to get much more attention. A new method of burning high-level transuranic (TRU) waste combined with Thorium-Uranium (Th-U) fuel in the subcritical reactors driven by external fusion neutron sources is proposed in this paper. The thorium-based TRU fuel burns all of the long-lived actinides via a hard neutron spectrum while outputting power. A one-dimensional model of the reactor concept was built by means of the ONESN_BURN code with new data libraries. The numerical results included actinide radioactivity, biological hazard potential, and much higher burnup rate of high-level transuranic waste. The comparison of the fusion-fission reactor with the thermal reactor shows that the harder neutron spectrum is more efficient than the soft. The Th-U cycle produces less TRU, less radiotoxicity and fewer long-lived actinides. The Th-U cycle provides breeding of 233U with a long operation time (>20 years), hence significantly reducing the reactivity swing while improving safety and burnup.

  10. Learning high-level features for chord recognition using Autoencoder

    NASA Astrophysics Data System (ADS)

    Phongthongloa, Vilailukkana; Kamonsantiroj, Suwatchai; Pipanmaekaporn, Luepol

    2016-07-01

    Chord transcription is valuable to do by itself. It is known that the manual transcription of chords is very tiresome, time-consuming. It requires, moreover, musical knowledge. Automatic chord recognition has recently attracted a number of researches in the Music Information Retrieval field. It has known that a pitch class profile (PCP) is the commonly signal representation of musical harmonic analysis. However, the PCP may contain additional non-harmonic noise such as harmonic overtones and transient noise. The problem of non-harmonic might be generating the sound energy in term of frequency more than the actual notes of the respective chord. Autoencoder neural network may be trained to learn a mapping from low level feature to one or more higher-level representation. These high-level representations can explain dependencies of the inputs and reduce the effect of non-harmonic noise. Then these improve features are fed into neural network classifier. The proposed high-level musical features show 80.90% of accuracy. The experimental results have shown that the proposed approach can achieve better performance in comparison with other based method.

  11. High level language-based robotic control system

    NASA Technical Reports Server (NTRS)

    Rodriguez, Guillermo (Inventor); Kreutz, Kenneth K. (Inventor); Jain, Abhinandan (Inventor)

    1996-01-01

    This invention is a robot control system based on a high level language implementing a spatial operator algebra. There are two high level languages included within the system. At the highest level, applications programs can be written in a robot-oriented applications language including broad operators such as MOVE and GRASP. The robot-oriented applications language statements are translated into statements in the spatial operator algebra language. Programming can also take place using the spatial operator algebra language. The statements in the spatial operator algebra language from either source are then translated into machine language statements for execution by a digital control computer. The system also includes the capability of executing the control code sequences in a simulation mode before actual execution to assure proper action at execution time. The robot's environment is checked as part of the process and dynamic reconfiguration is also possible. The languages and system allow the programming and control of multiple arms and the use of inward/outward spatial recursions in which every computational step can be related to a transformation from one point in the mechanical robot to another point to name two major advantages.

  12. High level language-based robotic control system

    NASA Technical Reports Server (NTRS)

    Rodriguez, Guillermo (Inventor); Kruetz, Kenneth K. (Inventor); Jain, Abhinandan (Inventor)

    1994-01-01

    This invention is a robot control system based on a high level language implementing a spatial operator algebra. There are two high level languages included within the system. At the highest level, applications programs can be written in a robot-oriented applications language including broad operators such as MOVE and GRASP. The robot-oriented applications language statements are translated into statements in the spatial operator algebra language. Programming can also take place using the spatial operator algebra language. The statements in the spatial operator algebra language from either source are then translated into machine language statements for execution by a digital control computer. The system also includes the capability of executing the control code sequences in a simulation mode before actual execution to assure proper action at execution time. The robot's environment is checked as part of the process and dynamic reconfiguration is also possible. The languages and system allow the programming and control of multiple arms and the use of inward/outward spatial recursions in which every computational step can be related to a transformation from one point in the mechanical robot to another point to name two major advantages.

  13. Local acceptance of a high-level nuclear waste repository.

    PubMed

    Sjöberg, Lennart

    2004-06-01

    The siting of nuclear waste facilities has been very difficult in all countries. Recent experience in Sweden indicates, however, that it may be possible, under certain circumstances, to gain local support for the siting of a high-level nuclear waste (HLNW) repository. The article reports on a study of attitudes and risk perceptions of people living in four municipalities in Sweden where HLNW siting was being intensely discussed at the political level, in media, and among the public. Data showed a relatively high level of consensus on acceptability of at least further investigation of the issue; in two cases local councils have since voted in favor of a go-ahead, and in one case only a very small majority defeated the issue. Models of policy attitudes showed that these were related to attitude to nuclear power, attributes of the perceived HLNW risk, and trust. Factors responsible for acceptance are discussed at several levels. One is the attitude to nuclear power, which is becoming more positive, probably because no viable alternatives are in sight. Other factors have to do with the extensive information programs conducted in these municipalities, and with the logical nature of the conclusion that they would be good candidates for hosting the national HLNW repository.

  14. VITRIFICATION OF HIGH LEVEL WASTE AT THE SAVANNAH RIVER SITE

    SciTech Connect

    Fox, K.; Peeler, D.

    2009-06-17

    The objective of this study was to experimentally measure the properties and performance of a series of glasses with compositions that could represent high level waste Sludge Batch 5 (SB5) as vitrified at the Savannah River Site Defense Waste Processing Facility. These data were used to guide frit optimization efforts as the SB5 composition was finalized. Glass compositions for this study were developed by combining a series of SB5 composition projections with a group of candidate frits. The study glasses were fabricated using depleted uranium and their chemical compositions, crystalline contents and chemical durabilities were characterized. Trevorite was the only crystalline phase that was identified in a few of the study glasses after slow cooling, and is not of concern as spinels have been shown to have little impact on the durability of high level waste glasses. Chemical durability was quantified using the Product Consistency Test (PCT). All of the glasses had very acceptable durability performance. The results of this study indicate that a frit composition can be identified that will provide a processable and durable glass when combined with SB5.

  15. High level radioactive waste glass production and product description

    SciTech Connect

    Sproull, J.F.; Marra, S.L.; Jantzen, C.M.

    1993-12-01

    This report examines borosilicate glass as a means of immobilizing high-level radioactive wastes. Borosilicate glass will encapsulate most of the defense and some of the commercial HLW in the US. The resulting waste forms must meet the requirements of the WA-SRD and the WAPS, which include a short term PCT durability test. The waste form producer must report the composition(s) of the borosilicate waste glass(es) produced but can choose the composition(s) to meet site-specific requirements. Although the waste form composition is the primary determinant of durability, the redox state of the glass; the existence, content, and composition of crystals; and the presence of glass-in-glass phase separation can affect durability. The waste glass should be formulated to avoid phase separation regions. The ultimate result of this effort will be a waste form which is much more stable and potentially less mobile than the liquid high level radioactive waste is currently.

  16. Spent fuel and high-level radioactive waste transportation report

    SciTech Connect

    Not Available

    1989-11-01

    This publication is intended to provide its readers with an introduction to the issues surrounding the subject of transportation of spent nuclear fuel and high-level radioactive waste, especially as those issues impact the southern region of the United States. It was originally issued by the Southern States Energy Board (SSEB) in July 1987 as the Spent Nuclear Fuel and High-Level Radioactive Waste Transportation Primer, a document patterned on work performed by the Western Interstate Energy Board and designed as a ``comprehensive overview of the issues.`` This work differs from that earlier effort in that it is designed for the educated layman with little or no background in nuclear waste issues. In addition, this document is not a comprehensive examination of nuclear waste issues but should instead serve as a general introduction to the subject. Owing to changes in the nuclear waste management system, program activities by the US Department of Energy and other federal agencies and developing technologies, much of this information is dated quickly. While this report uses the most recent data available, readers should keep in mind that some of the material is subject to rapid change. SSEB plans periodic updates in the future to account for changes in the program. Replacement pages sew be supplied to all parties in receipt of this publication provided they remain on the SSEB mailing list.

  17. How to achieve high-level expression of microbial enzymes

    PubMed Central

    Liu, Long; Yang, Haiquan; Shin, Hyun-dong; Chen, Rachel R.; Li, Jianghua; Du, Guocheng; Chen, Jian

    2013-01-01

    Microbial enzymes have been used in a large number of fields, such as chemical, agricultural and biopharmaceutical industries. The enzyme production rate and yield are the main factors to consider when choosing the appropriate expression system for the production of recombinant proteins. Recombinant enzymes have been expressed in bacteria (e.g., Escherichia coli, Bacillus and lactic acid bacteria), filamentous fungi (e.g., Aspergillus) and yeasts (e.g., Pichia pastoris). The favorable and very advantageous characteristics of these species have resulted in an increasing number of biotechnological applications. Bacterial hosts (e.g., E. coli) can be used to quickly and easily overexpress recombinant enzymes; however, bacterial systems cannot express very large proteins and proteins that require post-translational modifications. The main bacterial expression hosts, with the exception of lactic acid bacteria and filamentous fungi, can produce several toxins which are not compatible with the expression of recombinant enzymes in food and drugs. However, due to the multiplicity of the physiological impacts arising from high-level expression of genes encoding the enzymes and expression hosts, the goal of overproduction can hardly be achieved, and therefore, the yield of recombinant enzymes is limited. In this review, the recent strategies used for the high-level expression of microbial enzymes in the hosts mentioned above are summarized and the prospects are also discussed. We hope this review will contribute to the development of the enzyme-related research field. PMID:23686280

  18. Spent fuel and high-level radioactive waste transportation report

    SciTech Connect

    Not Available

    1990-11-01

    This publication is intended to provide its readers with an introduction to the issues surrounding the subject of transportation of spent nuclear fuel and high-level radioactive waste, especially as those issues impact the southern region of the United States. It was originally issued by the Southern States Energy Board (SSEB) in July 1987 as the Spent Nuclear Fuel and High-Level Radioactive Waste Transportation Primer, a document patterned on work performed by the Western Interstate Energy Board and designed as a ``comprehensive overview of the issues.`` This work differs from that earlier effort in that it is designed for the educated layman with little or no background in nuclear waste issues. In addition, this document is not a comprehensive examination of nuclear waste issues but should instead serve as a general introduction to the subject. Owing to changes in the nuclear waste management system, program activities by the US Department of Energy and other federal agencies and developing technologies, much of this information is dated quickly. While this report uses the most recent data available, readers should keep in mind that some of the material is subject to rapid change. SSEB plans periodic updates in the future to account for changes in the program. Replacement pages will be supplied to all parties in receipt of this publication provided they remain on the SSEB mailing list.

  19. FLUIDIZED BED STEAM REFORMING ENABLING ORGANIC HIGH LEVEL WASTE DISPOSAL

    SciTech Connect

    Williams, M

    2008-05-09

    Waste streams planned for generation by the Global Nuclear Energy Partnership (GNEP) and existing radioactive High Level Waste (HLW) streams containing organic compounds such as the Tank 48H waste stream at Savannah River Site have completed simulant and radioactive testing, respectfully, by Savannah River National Laboratory (SRNL). GNEP waste streams will include up to 53 wt% organic compounds and nitrates up to 56 wt%. Decomposition of high nitrate streams requires reducing conditions, e.g. provided by organic additives such as sugar or coal, to reduce NOX in the off-gas to N2 to meet Clean Air Act (CAA) standards during processing. Thus, organics will be present during the waste form stabilization process regardless of the GNEP processes utilized and exists in some of the high level radioactive waste tanks at Savannah River Site and Hanford Tank Farms, e.g. organics in the feed or organics used for nitrate destruction. Waste streams containing high organic concentrations cannot be stabilized with the existing HLW Best Developed Available Technology (BDAT) which is HLW vitrification (HLVIT) unless the organics are removed by pretreatment. The alternative waste stabilization pretreatment process of Fluidized Bed Steam Reforming (FBSR) operates at moderate temperatures (650-750 C) compared to vitrification (1150-1300 C). The FBSR process has been demonstrated on GNEP simulated waste and radioactive waste containing high organics from Tank 48H to convert organics to CAA compliant gases, create no secondary liquid waste streams and create a stable mineral waste form.

  20. Space augmentation of military high-level waste disposal

    NASA Technical Reports Server (NTRS)

    English, T.; Lees, L.; Divita, E.

    1979-01-01

    Space disposal of selected components of military high-level waste (HLW) is considered. This disposal option offers the promise of eliminating the long-lived radionuclides in military HLW from the earth. A space mission which meets the dual requirements of long-term orbital stability and a maximum of one space shuttle launch per week over a period of 20-40 years, is a heliocentric orbit about halfway between the orbits of earth and Venus. Space disposal of high-level radioactive waste is characterized by long-term predictability and short-term uncertainties which must be reduced to acceptably low levels. For example, failure of either the Orbit Transfer Vehicle after leaving low earth orbit, or the storable propellant stage failure at perihelion would leave the nuclear waste package in an unplanned and potentially unstable orbit. Since potential earth reencounter and subsequent burn-up in the earth's atmosphere is unacceptable, a deep space rendezvous, docking, and retrieval capability must be developed.

  1. Status of high-level waste processing at West Valley

    SciTech Connect

    Howell, A.J.; Baker, M.N. )

    1991-11-01

    The US Department of Energy is charged with the solidification of high-level liquid waste remaining from nuclear fuel reprocessing activities that were conducted at West Valley, New York, between 1966 and 1972. The 2.27 million liters (600,000 gal) of waste in an underground storage tank has separated into a sludge layer, {approximately}10% of the original volume, and a liquid layer. Prior to the high-level waste (HLW) vitrification, volume reduction of the waste is necessary. Sine May 1988, West Valley has successfully processed >1.59 million liters (420,000 gal) of HLW. Processing to date has involved the removal of {sup 139}Cs from the HLW effluent by ion exchange, evaporation to concentrate the effluent to a predetermined salt concentration, and finally cementation. This process has removed {approximately}80% of the {sup 137}Cs from the HLW liquid phase. Modifications are currently being made to begin the second phase of the HLW processing at West Valley. The second phase of HLW processing will include the removal of plutonium as well as cesium from the HLW sludge. This paper describes the progress made to date and the modifications being made to the process and to the feed stream to begin the second phase of HLW processing.

  2. Permitting plan for the high-level waste interim storage

    SciTech Connect

    Deffenbaugh, M.L.

    1997-04-23

    This document addresses the environmental permitting requirements for the transportation and interim storage of solidified high-level waste (HLW) produced during Phase 1 of the Hanford Site privatization effort. Solidified HLW consists of canisters containing vitrified HLW (glass) and containers that hold cesium separated during low-level waste pretreatment. The glass canisters and cesium containers will be transported to the Canister Storage Building (CSB) in a U.S. Department of Energy (DOE)-provided transportation cask via diesel-powered tractor trailer. Tri-Party Agreement (TPA) Milestone M-90 establishes a new major milestone, and associated interim milestones and target dates, governing acquisition and/or modification of facilities necessary for: (1) interim storage of Tank Waste Remediation Systems (TWRS) immobilized HLW (IHLW) and other canistered high-level waste forms; and (2) interim storage and disposal of TWRS immobilized low-activity tank waste (ILAW). An environmental requirements checklist and narrative was developed to identify the permitting path forward for the HLW interim storage (HLWIS) project (See Appendix B). This permitting plan will follow the permitting logic developed in that checklist.

  3. In Vitro Activity of Ampicillin or Vancomycin Combined with Gentamicin or Streptomycin Against Enterococci

    PubMed Central

    Harwick, Herbert J.; Kalmanson, George M.; Guze, Lucien B.

    1973-01-01

    Minimum inhibitory and bactericidal concentrations of four antibiotics and their combinations were determined for 38 strains of enterococci by a microtitration tube dilution technique. The drugs were ampicillin, vancomycin, gentamicin, and streptomycin; the combinations were ampicillin-gentamicin, ampicillin-streptomycin, vancomycin-gentamicin, and vancomycin-streptomycin. At achievable serum concentrations, ampicillin alone killed 60% of strains, whereas combination with streptomycin increased this to 90% and with gentamicin to 100%. Vancomycin alone showed striking inhibitory activity, but very poor bactericidal activity at achievable concentrations. Combination with one of the aminoglycosides increased the bactericidal activity substantially. When combined with ampicillin, gentamicin was both more active and showed synergistic bactericidal activity significantly more often (P < 0.01) than streptomycin. PMID:4791300

  4. Detection of clinically relevant genotypes of vancomycin-resistant enterococci in nosocomial surveillance specimens by PCR.

    PubMed

    Jayaratne, P; Rutherford, C

    1999-06-01

    This study evaluated a PCR method for the rapid detection of clinically significant genotypes of vancomycin-resistant enterococci (VRE) in nosocomial surveillance specimens. Detection of the vanA and vanB genes by multiplex PCR using 657 specimens that showed presumptive growth of VRE on bile esculin azide agar containing 6 mg of vancomycin/liter was compared to the conventional method. The diagnostic values for the PCR compared to the phenotypic method were as follows: 99.8% specificity, 95.4% sensitivity, 98.8% positive predictive value, and 99.3% negative predictive value. The average cost per test for PCR is $8.26, compared to $9.45 for the phenotypic method. The average turnaround time for detecting a VRE is 48 h for PCR, compared to 96 h for the conventional method.

  5. COMPARISON OF DIRECT PLATING MEDIA FOR THE ISOLATION AND ENUMERATION OF ENTEROCOCCI IN CERTAIN FROZEN FOODS.

    PubMed

    BURKWALL, M K; HARTMAN, P A

    1964-01-01

    A total of 15 agar media were examined for their yield, selectivity, readability, and simplicity of preparation and use. A thallium medium of Barnes was selected as the better of the high yield-fair selectivity type of medium and an azide-citrate medium of Reinbold appeared to be the better of the low yield-high selectivity type of medium. Sodium carbonate (optimal concentration, 0.20%) was found to increase recovery substantially when added to certain media, especially in the presence of 0.05% Tween 80. When these two ingredients were incorporated into a medium modified after Slanetz and Bartley, the resultant medium was superior to other media for the isolation and enumeration of enterococci in certain frozen foods, such as peas and hamburger, by the direct plating method.

  6. Molecular typing, pathogenicity factor genes and antimicrobial susceptibility of vancomycin resistant enterococci in Belgrade, Serbia.

    PubMed

    Jovanović, Milica; Milošević, Branko; Tošić, Tanja; Stevanović, Goran; Mioljević, Vesna; Inđić, Nikola; Velebit, Branko; Zervos, Marcus

    2015-06-01

    In this study the distribution of species and antimicrobial resistance among vancomycin resistant enterococci (VRE) recovered from clinical specimens obtained from five hospitals in Belgrade was analyzed. Strains were further characterized by pulsed-field gel electrophoresis (PFGE). Polymerase chain reaction (PCR) was used to investigate the presence of vanA and vanB genes and pathogenicity factor genes. Identification of 194 VRE isolates revealed 154 Enterococcus faecium, 21 Enterococcus faecalis, 10 Enterococcus raffinosus and 9 Enterococcus gallinarum. This study revealed existence of 8 major clones of VRE. PCR determined vanA gene to be present in all of the VRE studied. Esp and hyl genes were present in 29.22% and 27.92% of E. faecium, respectively, and in 76.19% and 0 of E. faecalis, respectively. Esp and hyl genes were not found more frequently in members of predominant clones of E. faecium than in single isolates; nor was their presence connected to invasiveness.

  7. Vancomycin-resistant enterococci outside the health-care setting: prevalence, sources, and public health implications.

    PubMed Central

    McDonald, L. C.; Kuehnert, M. J.; Tenover, F. C.; Jarvis, W. R.

    1997-01-01

    Although nosocomial acquisition and subsequent colonization of vancomycin-resistant enterococci (VRE), an emerging international threat to public health, has been emphasized in the United States, colonization among nonhospitalized persons has been infrequently documented. In contrast, in Europe, colonization appears to occur frequently in persons outside the health-care setting. An important factor associated with VRE in the community in Europe has been avoparcin, a glycopeptide antimicrobial drug used for years in many European nations at subtherapeutic doses as a growth promoter in food-producing animals. In Europe, evidence suggests that foodborne VRE may cause human colonization. Although avoparcin has never been approved for use in the United States, undetected community VRE transmission may be occurring at low levels. Further studies of community transmission of VRE in the United States are urgently needed. If transmission with VRE from unrecognized community sources can be identified and controlled, increased incidence of colonization and infection among hospitalized patients may be prevented. PMID:9284375

  8. [Vancomycin-resistant enterococci in pediatric hematology: don't panic!].

    PubMed

    Barbé, G; Ploton, C; Pondarré, C; Bertrand, Y; Souillet, G; Philippe, N

    1998-06-01

    Do immunocompromised children, carrying vancomycin-resistant enterococci (VRE) need to be treated? For 3 years, 230 children with chemotherapy and/or bone-marrow transplantation (BMT) received amikacin for gut decontamination and rinsed their mouth with solutions including vancomycin or not, according to the duration and severity of neutropenia. Some patients were isolated, others were at home with ambulatory treatment. The first-line antibio-therapy was piperacillin-amikacin-vancomycin in the chemotherapy unit, imipenem-vancomycin in the BMT unit. Once-a-week, the laboratory used to check the efficiency of decontamination procedures and look for emerging resistant bacteria. Four patients were identified as VRE carriers in their gut flora. The fecal carriage was long-lasting in a single patient, for whom attempts of eradication failed. No patient underwent VRE bacteremia. From our experience, it seems reasonable to neglect enterococcal eradication, provided that hygienic measures are strictly applied.

  9. Clonal Diversity in Multi Drug Resistant (MDR) Enterococci Isolated from Fecal Normal Flora.

    PubMed

    Hasannejad Bibalan, Meysam; Eshaghi, Morteza; Sadeghi, Javad; Asadian, Mahla; Narimani, Tahmineh; Talebi, Malihe

    2015-01-01

    Enterococci are Gram positive and catalase- negative cocci that are found in the gastrointestinal tract of mammals and birds, and are readily isolated from soil, surface and waters. The aim of this study was to discriminate between Enterococcus isolates based on repetitive element sequence based -PCR (Rep-PCR) with the BOXA2R primer and their antibiotics profile. Enterococci isolates were obtained from 180 fecal samples. The isolates were identified by biochemical reaction and specific identification was confirmed by PCR with species specific primers. All isolates were subjected to Rep typing and antimicrobial susceptibility tests. Rep-PCR analysis of 180 isolates revealed 93 REP types with forty-five single types (ST1 to ST45) and forty-eight common types (CT1 to 48). Antibiotic susceptibility tests exhibited that 53 (29.4%), 43 (23.8%), 11 (6.1%) and 9 (5%) were resistant to erythromycin, tetracycline, gentamicin and ciprofloxacin respectively but among the isolates, sixteen were multi drug resistant (MDR). These MDR isolates showed 11 Rep types with seven single types and four common types. In addition, 81.2% of MDR isolates were from male subjects and the average age of these persons was more than fifty years. This study showed that 56.2% of MDR isolates were homogeneous with 95 % similarity, and high rate of resistance to tetracycline and erythromycin (81.2%) were observed in these isolates. The concern about these normal flora isolates are the pathogenic potential of these bacteria through the horizontal transfer of antibiotic resistance and virulence genes.

  10. Clonal Diversity in Multi Drug Resistant (MDR) Enterococci Isolated from Fecal Normal Flora

    PubMed Central

    Hasannejad Bibalan, Meysam; Eshaghi, Morteza; Sadeghi, Javad; Asadian, Mahla; Narimani, Tahmineh; Talebi, Malihe

    2015-01-01

    Enterococci are Gram positive and catalase- negative cocci that are found in the gastrointestinal tract of mammals and birds, and are readily isolated from soil, surface and waters. The aim of this study was to discriminate between Enterococcus isolates based on repetitive element sequence based –PCR (Rep-PCR) with the BOXA2R primer and their antibiotics profile. Enterococci isolates were obtained from 180 fecal samples. The isolates were identified by biochemical reaction and specific identification was confirmed by PCR with species specific primers. All isolates were subjected to Rep typing and antimicrobial susceptibility tests. Rep-PCR analysis of 180 isolates revealed 93 REP types with forty-five single types (ST1 to ST45) and forty-eight common types (CT1 to 48). Antibiotic susceptibility tests exhibited that 53 (29.4%), 43 (23.8%), 11 (6.1%) and 9 (5%) were resistant to erythromycin, tetracycline, gentamicin and ciprofloxacin respectively but among the isolates, sixteen were multi drug resistant (MDR). These MDR isolates showed 11 Rep types with seven single types and four common types. In addition, 81.2% of MDR isolates were from male subjects and the average age of these persons was more than fifty years. This study showed that 56.2% of MDR isolates were homogeneous with 95 % similarity, and high rate of resistance to tetracycline and erythromycin (81.2%) were observed in these isolates. The concern about these normal flora isolates are the pathogenic potential of these bacteria through the horizontal transfer of antibiotic resistance and virulence genes. PMID:27014649

  11. Human health risks associated with antimicrobial-resistant enterococci and Staphylococcus aureus on poultry meat.

    PubMed

    Bortolaia, V; Espinosa-Gongora, C; Guardabassi, L

    2016-02-01

    Enterococci and staphylococci are frequent contaminants on poultry meat. Enterococcus faecalis, Enterococcus faecium and Staphylococcus aureus are also well-known aetiological agents of a wide variety of infections resulting in major healthcare costs. This review provides an overview of the human health risks associated with the occurrence of these opportunistic human pathogens on poultry meat with particular focus on the risk of food-borne transmission of antimicrobial resistance. In the absence of conclusive evidence of transmission, this risk was inferred using data from scientific articles and national reports on prevalence, bacterial load, antimicrobial resistance and clonal distribution of these three species on poultry meat. The risks associated with ingestion of antimicrobial-resistant enterococci of poultry origin comprise horizontal transfer of resistance genes and transmission of multidrug-resistant E. faecalis lineages such as sequence type ST16. Enterococcus faecium lineages occurring in poultry meat products are distantly related to those causing hospital-acquired infections but may act as donors of quinupristin/dalfopristin resistance and other resistance determinants of clinical interest to the human gut microbiota. Ingestion of poultry meat contaminated with S. aureus may lead to food poisoning. However, antimicrobial resistance in the toxin-producing strains does not have clinical implications because food poisoning is not managed by antimicrobial therapy. Recently methicillin-resistant S. aureus of livestock origin has been reported on poultry meat. In theory handling or ingestion of contaminated meat is a potential risk factor for colonization by methicillin-resistant S. aureus. However, this risk is presently regarded as negligible by public health authorities.

  12. Inducible expression eliminates the fitness cost of vancomycin resistance in enterococci.

    PubMed

    Foucault, Marie-Laure; Depardieu, Florence; Courvalin, Patrice; Grillot-Courvalin, Catherine

    2010-09-28

    Inducible vancomycin resistance in enterococci is due to a sophisticated mechanism that combines synthesis of cell wall peptidoglycan precursors with low affinity for glycopeptides and elimination of the normal target precursors. Although this dual mechanism, which involves seven genes organized in two operons, is predicted to have a high fitness cost, resistant enterococci have disseminated worldwide. We have evaluated the biological cost of VanB-type resistance due to acquisition of conjugative transposon Tn1549 in Enterococcus faecium and Enterococcus faecalis. Because fitness was dependent on the integration site of Tn1549, an isogenic set of E. faecalis was constructed to determine the cost of inducible or constitutive expression of resistance or of carriage of Tn1549. A luciferase gene was inserted in the integrase gene of the transposon to allow differential quantification of the strains in cocultures and in the digestive tract of gnotobiotic mice. Both in vitro and in vivo, carriage of inactivated or inducible Tn1549 had no cost for the host in the absence of induction by vancomycin. In contrast, induced or constitutively resistant strains not only had reduced fitness but were severely impaired in colonization ability and dissemination among mice. These data indicate that tight regulation of resistance expression drastically reduces the biological cost associated with vancomycin resistance in Enterococcus spp. and accounts for the widespread dissemination of these strains. Our findings are in agreement with the observation that regulation of expression is common in horizontally acquired resistance and represents an efficient evolutionary pathway for resistance determinants to become selectively neutral.

  13. Detection of antibiotic resistant enterococci and Escherichia coli in free range Iberian Lynx (Lynx pardinus).

    PubMed

    Gonçalves, Alexandre; Igrejas, Gilberto; Radhouani, Hajer; Santos, Tiago; Monteiro, Ricardo; Pacheco, Rui; Alcaide, Eva; Zorrilla, Irene; Serra, Rodrigo; Torres, Carmen; Poeta, Patrícia

    2013-07-01

    Thirty fecal samples from wild specimens of Iberian lynx were collected and analyzed for Enterococcus spp. (27 isolates) and Escherichia coli (18 isolates) recovery. The 45 isolates obtained were tested for antimicrobial resistance, molecular mechanisms of resistance, and presence of virulence genes. Among the enterococci, Enterococcus faecium and Enterococcus hirae were the most prevalent species (11 isolates each), followed by Enterococcus faecalis (5 isolates). High percentages of resistance to tetracycline and erythromycin (33% and 30%, respectively) were detected among enterococcal isolates. The tet(M) and/or tet(L), erm(B), aac(6')-Ie-aph(2″)-Ia, ant(6)-Ia, or aph(3')-IIIa genes were detected among resistant enterococci. Virulence genes were detected in one E. faecalis isolate (cpd, cylB, and cylL) and one E. hirae isolate (cylL). High percentages of resistance were detected in E. coli isolates to tetracycline (33%), streptomycin (28%), nalidixic acid (28%), and sulfamethoxazole-trimethoprim (SXT, 22%). Additionally, the blaTEM, tet(A), aadA, cmlA, and different combinations of sul genes were detected among most ampicillin, tetracycline, streptomycin, chloramphenicol and SXT-resistant isolates, respectively. Two isolates contained a class 1 integron with the gene cassette arrays dfrA1 + aadA1 and dfrA12 + aadA2. The E. coli isolates were ascribed to phylo-groups A (n=5); B1 (n=4); B2 (n=6), and D (n=3), with the virulence gene fimA present in all E. coli isolates. This study found resistance genes in wild specimens of Iberian lynx. Thus, it is important to notice that multiresistant bacteria have reached species as rare and completely non-synanthropic as the Iberian lynx. Furthermore, the susceptibility of this endangered species to bacterial infection may be affected by the presence of these virulence and resistance genes.

  14. Mechanism of copper surface toxicity in vancomycin-resistant enterococci following wet or dry surface contact.

    PubMed

    Warnes, S L; Keevil, C W

    2011-09-01

    Contaminated touch surfaces have been implicated in the spread of hospital-acquired infections, and the use of biocidal surfaces could help to reduce this cross-contamination. In a previous study we reported the death of aqueous inocula of pathogenic Enterococcus faecalis or Enterococcus faecium isolates, simulating fomite surface contamination, in 1 h on copper alloys, compared to survival for months on stainless steel. In our current study we observed an even faster kill of over a 6-log reduction of viable enterococci in less than 10 min on copper alloys with a "dry" inoculum equivalent to touch contamination. We investigated the effect of copper(I) and copper(II) chelation and the quenching of reactive oxygen species on cell viability assessed by culture and their effects on genomic DNA, membrane potential, and respiration in situ on metal surfaces. We propose that copper surface toxicity for enterococci involves the direct or indirect action of released copper ionic species and the generation of superoxide, resulting in arrested respiration and DNA breakdown as the first stages of cell death. The generation of hydroxyl radicals by the Fenton reaction does not appear to be the dominant instrument of DNA damage. The bacterial membrane potential is unaffected in the early stages of wet and dry surface contact, suggesting that the membrane is not compromised until after cell death. These results also highlight the importance of correct surface cleaning protocols to perpetuate copper ion release and prevent the chelation of ions by contaminants, which could reduce the efficacy of the surface.

  15. Biocidal Efficacy of Copper Alloys against Pathogenic Enterococci Involves Degradation of Genomic and Plasmid DNAs ▿

    PubMed Central

    Warnes, S. L.; Green, S. M.; Michels, H. T.; Keevil, C. W.

    2010-01-01

    The increasing incidence of nosocomial infections caused by glycopeptide-resistant enterococci is a global concern. Enterococcal species are also difficult to eradicate with existing cleaning regimens; they can survive for long periods on surfaces, thus contributing to cases of reinfection and spread of antibiotic-resistant strains. We have investigated the potential use of copper alloys as bactericidal surfaces. Clinical isolates of vancomycin-resistant Enterococcus faecalis and Enterococcus faecium were inoculated onto copper alloy and stainless steel surfaces. Samples were assessed for the presence of viable cells by conventional culture, detection of actively respiring cells, and assessment of cell membrane integrity. Both species survived for up to several weeks on stainless steel. However, no viable cells were detected on any alloys following exposure for 1 h at an inoculum concentration of ≤104 CFU/cm2. Analysis of genomic and plasmid DNA from bacterial cells recovered from metal surfaces indicates substantial disintegration of the DNA following exposure to copper surfaces that is not evident in cells recovered from stainless steel. The DNA fragmentation is so extensive, and coupled with the rapid cell death which occurs on copper surfaces, that it suggests that mutation is less likely to occur. It is therefore highly unlikely that genetic information can be transferred to receptive organisms recontaminating the same area. A combination of effective cleaning regimens and contact surfaces containing copper could be useful not only to prevent the spread of viable pathogenic enterococci but also to mitigate against the occurrence of potential resistance to copper, biocides, or antibiotics and the spread of genetic determinants of resistance to other species. PMID:20581191

  16. High-Level Language Production in Parkinson's Disease: A Review

    PubMed Central

    Altmann, Lori J. P.; Troche, Michelle S.

    2011-01-01

    This paper discusses impairments of high-level, complex language production in Parkinson's disease (PD), defined as sentence and discourse production, and situates these impairments within the framework of current psycholinguistic theories of language production. The paper comprises three major sections, an overview of the effects of PD on the brain and cognition, a review of the literature on language production in PD, and a discussion of the stages of the language production process that are impaired in PD. Overall, the literature converges on a few common characteristics of language production in PD: reduced information content, impaired grammaticality, disrupted fluency, and reduced syntactic complexity. Many studies also document the strong impact of differences in cognitive ability on language production. Based on the data, PD affects all stages of language production including conceptualization and functional and positional processing. Furthermore, impairments at all stages appear to be exacerbated by impairments in cognitive abilities. PMID:21860777

  17. A high-level language for rule-based modelling.

    PubMed

    Pedersen, Michael; Phillips, Andrew; Plotkin, Gordon D

    2015-01-01

    Rule-based languages such as Kappa excel in their support for handling the combinatorial complexities prevalent in many biological systems, including signalling pathways. But Kappa provides little structure for organising rules, and large models can therefore be hard to read and maintain. This paper introduces a high-level, modular extension of Kappa called LBS-κ. We demonstrate the constructs of the language through examples and three case studies: a chemotaxis switch ring, a MAPK cascade, and an insulin signalling pathway. We then provide a formal definition of LBS-κ through an abstract syntax and a translation to plain Kappa. The translation is implemented in a compiler tool which is available as a web application. We finally demonstrate how to increase the expressivity of LBS-κ through embedded scripts in a general-purpose programming language, a technique which we view as generally applicable to other domain specific languages.

  18. Midwestern High-Level Radioactive Waste Transportation Project

    SciTech Connect

    Dantoin, T.S.

    1990-12-01

    For more than half a century, the Council of State Governments has served as a common ground for the states of the nation. The Council is a nonprofit, state-supported and -directed service organization that provides research and resources, identifies trends, supplies answers and creates a network for legislative, executive and judicial branch representatives. This List of Available Resources was prepared with the support of the US Department of Energy, Cooperative Agreement No. DE-FC02-89CH10402. However, any opinions, findings, conclusions, or recommendations expressed herein are those of the author(s) and do not necessarily reflect the views of DOE. The purpose of the agreement, and reports issued pursuant to it, is to identify and analyze regional issues pertaining to the transportation of high-level radioactive waste and to inform Midwestern state officials with respect to technical issues and regulatory concerns related to waste transportation.

  19. The SEISMED High Level Security Policy for Health Care.

    PubMed

    Katsikas, S K

    1996-01-01

    The proliferation of the use of automated Health Information Systems in the everyday practice of health professionals has brought a number of issues related to the security of health information to a critical point. The preservation of security of health-related information can only be achieved through a concerted approach, comprising legal, organisational, technical and educational actions. These classes of actions constitute a complete "security framework", a key aspect of which is the set of rules, laws and regulations that govern the usage of information within a Health Care Establishment. This set is commonly referred to as "Security Policy". In this paper, the SEISMED High Level Security Policy for Health Care Establishments is presented.

  20. High Level Waste System Impacts from Acid Dissolution of Sludge

    SciTech Connect

    KETUSKY, EDWARD

    2006-04-20

    This research evaluates the ability of OLI{copyright} equilibrium based software to forecast Savannah River Site High Level Waste system impacts from oxalic acid dissolution of Tank 1-15 sludge heels. Without further laboratory and field testing, only the use of oxalic acid can be considered plausible to support sludge heel dissolution on multiple tanks. Using OLI{copyright} and available test results, a dissolution model is constructed and validated. Material and energy balances, coupled with the model, identify potential safety concerns. Overpressurization and overheating are shown to be unlikely. Corrosion induced hydrogen could, however, overwhelm the tank ventilation. While pH adjustment can restore the minimal hydrogen generation, resultant precipitates will notably increase the sludge volume. OLI{copyright} is used to develop a flowsheet such that additional sludge vitrification canisters and other negative system impacts are minimized. Sensitivity analyses are used to assess the processability impacts from variations in the sludge/quantities of acids.

  1. High-level theoretical rovibrational spectroscopy of HCS+ isotopologues

    NASA Astrophysics Data System (ADS)

    Schröder, B.; Sebald, P.

    2016-12-01

    In this work the rovibrational spectrum of the HCS+ molecular cation is revisited through high-level electronic structure and variational rovibrational calculations. A local potential energy function is built from explicitly correlated coupled-cluster results, incorporating corrections for core-valence, scalar relativistic and higher-order excitation effects. The computed spectroscopic parameters, based on variational calculations with Watson's isomorphic Hamiltonian for linear molecules lead to a nearly perfect agreement with experimentally reported values (Rosenbaum et al., 1989). Furthermore, the documented Fermi resonance within the (0,00, 1) / (0,20, 0) and (1,00, 1) / (1,20, 0) pairs of states is clarified. Based on a newly developed electric dipole moment function transition dipole moments of fundamental transitions are predicted for the most important isotopologues.

  2. High-level tetracycline resistant Neisseria gonorrhoeae isolated in Portugal.

    PubMed

    Ferreira, E; Louro, D; Gomes, J P; Catry, M A; Pato, M V

    1997-05-01

    The first high-level tetracycline resistance (MIC > or = 16 mg/l) isolates of Neisseria gonorrhoeae (TRNG) were reported in 1990 from patients attending a Sexual Transmitted Disease (STD) Center in Lisbon. The TRNG prevalence was 4% in 1991, 5.3% in 1992 and 10,8% in 1994, exploding to 52.2% in 1995. The tet M determinant was evaluated by PCR. The digests of PCRP using HpaII produced the restriction pattern 2 for all the strains, except one (pattern 3). 78.3% of the TRNG strains were beta-lactamase producers and the 4.5 MDa penicillinase plasmid was the dominant (83%), 90% and 93.3% of the TRNG strains belonged to the auxotype NR and to the serogroup IA, respectively. The IA-8/NR class represented 58.3% of the TRNG isolates, suggesting a clonal spreading.

  3. High level radioactive waste vitrification process equipment component testing

    SciTech Connect

    Siemens, D.H.; Heath, W.O.; Larson, D.E.; Craig, S.N.; Berger, D.N.; Goles, R.W.

    1985-04-01

    Remote operability and maintainability of vitrification equipment were assessed under shielded-cell conditions. The equipment tested will be applied to immobilize high-level and transuranic liquid waste slurries that resulted from plutonium production for defense weapons. Equipment tested included: a turntable for handling waste canisters under the melter; a removable discharge cone in the melter overflow section; a thermocouple jumper that extends into a shielded cell; remote instrument and electrical connectors; remote, mechanical, and heat transfer aspects of the melter glass overflow section; a reamer to clean out plugged nozzles in the melter top; a closed circuit camera to view the melter interior; and a device to retrieve samples of the glass product. A test was also conducted to evaluate liquid metals for use in a liquid metal sealing system.

  4. Quasimonomorphic mononucleotide repeats for high-level microsatellite instability analysis.

    PubMed

    Buhard, Olivier; Suraweera, Nirosha; Lectard, Aude; Duval, Alex; Hamelin, Richard

    2004-01-01

    Microsatellite instability (MSI) analysis is becoming more and more important to detect sporadic primary tumors of the MSI phenotype as well as in helping to determine Hereditary Non-Polyposis Colorectal Cancer (HNPCC) cases. After some years of conflicting data due to the absence of consensus markers for the MSI phenotype, a meeting held in Bethesda to clarify the situation proposed a set of 5 microsatellites (2 mononucleotide repeats and 3 dinucleotide repeats) to determine MSI tumors. A second Bethesda consensus meeting was held at the end of 2002. It was discussed here that the 1998 microsatellite panel could underestimate high-level MSI tumors and overestimate low-level MSI tumors. Amongst the suggested changes was the exclusive use of mononucleotide repeats in place of dinucleotide repeats. We have already proposed a pentaplex MSI screening test comprising 5 quasimonomorphic mononucleotide repeats. This article compares the advantages of mono or dinucleotide repeats in determining microsatellite instability.

  5. Quasimonomorphic Mononucleotide Repeats for High-Level Microsatellite Instability Analysis

    PubMed Central

    Buhard, Olivier; Suraweera, Nirosha; Lectard, Aude; Duval, Alex; Hamelin, Richard

    2004-01-01

    Microsatellite instability (MSI) analysis is becoming more and more important to detect sporadic primary tumors of the MSI phenotype as well as in helping to determine Hereditary Non-Polyposis Colorectal Cancer (HNPCC) cases. After some years of conflicting data due to the absence of consensus markers for the MSI phenotype, a meeting held in Bethesda to clarify the situation proposed a set of 5 microsatellites (2 mononucleotide repeats and 3 dinucleotide repeats) to determine MSI tumors. A second Bethesda consensus meeting was held at the end of 2002. It was discussed here that the 1998 microsatellite panel could underestimate high-level MSI tumors and overestimate low-level MSI tumors. Amongst the suggested changes was the exclusive use of mononucleotide repeats in place of dinucleotide repeats. We have already proposed a pentaplex MSI screening test comprising 5 quasimonomorphic mononucleotide repeats. This article compares the advantages of mono or dinucleotide repeats in determining microsatellite instability. PMID:15528790

  6. Socioeconomic studies of high-level nuclear waste disposal.

    PubMed Central

    White, G F; Bronzini, M S; Colglazier, E W; Dohrenwend, B; Erikson, K; Hansen, R; Kneese, A V; Moore, R; Page, E B; Rappaport, R A

    1994-01-01

    The socioeconomic investigations of possible impacts of the proposed repository for high-level nuclear waste at Yucca Mountain, Nevada, have been unprecedented in several respects. They bear on the public decision that sooner or later will be made as to where and how to dispose permanently of the waste presently at military weapons installations and that continues to accumulate at nuclear power stations. No final decision has yet been made. There is no clear precedent from other countries. The organization of state and federal studies is unique. The state studies involve more disciplines than any previous efforts. They have been carried out in parallel to federal studies and have pioneered in defining some problems and appropriate research methods. A recent annotated bibliography provides interested scientists with a compact guide to the 178 published reports, as well as to relevant journal articles and related documents. PMID:7971963

  7. SIMULANT DEVELOPMENT FOR SAVANNAH RIVER SITE HIGH LEVEL WASTE

    SciTech Connect

    Stone, M; Russell Eibling, R; David Koopman, D; Dan Lambert, D; Paul Burket, P

    2007-09-04

    The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste (HLW) for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides (primarily iron, aluminum, magnesium, manganese, and uranium) and soluble sodium salts (carbonate, hydroxide, nitrite, nitrate, and sulfate). The HLW is processed in large batches through DWPF; DWPF has recently completed processing Sludge Batch 3 (SB3) and is currently processing Sludge Batch 4 (SB4). The composition of metal species in SB4 is shown in Table 1 as a function of the ratio of a metal to iron. Simulants remove radioactive species and renormalize the remaining species. Supernate composition is shown in Table 2.

  8. Exceptionally high levels of multiple mating in an army ant

    NASA Astrophysics Data System (ADS)

    Denny, A. Jay; Franks, Nigel R.; Powell, Scott; Edwards, Keith J.

    Most species of social insects have singly mated queens, although there are notable exceptions. Competing hypotheses have been proposed to explain the evolution of high levels of multiple mating, but this issue is far from resolved. Here we use microsatellites to investigate mating frequency in the army ant Eciton burchellii and show that queens mate with an exceptionally large number of males, eclipsing all but one other social insect species for which data are available. In addition we present evidence that suggests that mating is serial, continuing throughout the lifetime of the queen. This is the first demonstration of serial mating among social hymenoptera. We propose that high paternity within colonies is most likely to have evolved to increase genetic diversity and to counter high pathogen and parasite loads.

  9. Review of High Level Waste Tanks Ultrasonic Inspection Data

    SciTech Connect

    Wiersma, B

    2006-03-09

    A review of the data collected during ultrasonic inspection of the Type I high level waste tanks has been completed. The data was analyzed for relevance to the possibility of vapor space corrosion and liquid/air interface corrosion. The review of the Type I tank UT inspection data has confirmed that the vapor space general corrosion is not an unusually aggressive phenomena and correlates well with predicted corrosion rates for steel exposed to bulk solution. The corrosion rates are seen to decrease with time as expected. The review of the temperature data did not reveal any obvious correlations between high temperatures and the occurrences of leaks. The complex nature of temperature-humidity interaction, particularly with respect to vapor corrosion requires further understanding to infer any correlation. The review of the waste level data also did not reveal any obvious correlations.

  10. Reinforcement learning for high-level fuzzy Petri nets.

    PubMed

    Shen, V L

    2003-01-01

    The author has developed a reinforcement learning algorithm for the high-level fuzzy Petri net (HLFPN) models in order to perform structure and parameter learning simultaneously. In addition to the HLFPN itself, the difference and similarity among a variety of subclasses concerning Petri nets are also discussed. As compared with the fuzzy adaptive learning control network (FALCON), the HLFPN model preserves the advantages that: 1) it offers more flexible learning capability because it is able to model both IF-THEN and IF-THEN-ELSE rules; 2) it allows multiple heterogeneous outputs to be drawn if they exist; 3) it offers a more compact data structure for fuzzy production rules so as to save information storage; and 4) it is able to learn faster due to its structural reduction. Finally, main results are presented in the form of seven propositions and supported by some experiments.

  11. ALICE: Project Overview and High Level Science Products

    NASA Astrophysics Data System (ADS)

    Soummer, Remi; Choquet, Elodie; Pueyo, Laurent; Brendan Hagan, J.; Gofas-Salas, Elena; Rajan, Abhijith; Perrin, Marshall D.; Chen, Christine; Debes, John H.; Golimowski, David A.; Hines, Dean C.; Schneider, Glenn; N'Diaye, Mamadou; Mawet, Dimitri; Marois, Christian; Barman, Travis

    2015-01-01

    We report on the status of the ALICE project (Archival Legacy Investigation of Circumstellar Environments), which consists in a consistent reanalysis of the entire HST-NICMOS coronagraphic archive. Over the last two years, we have developed a sophisticated pipeline able to handle the data of the 400 stars of the archive. This pipeline builds on the Karhunen-Loeve Image Projection (KLIP) algorithm, and was completed in the fall of 2014. We discuss the first processing and analysis results of the overall reduction campaign. As we will deliver high-level science products to the STScI MAST archive, we are defining a new standard format for high-contrast science products, which will be compatible with every new high-contrast imaging instrument (GPI, SPHERE, P1640, CHARIS, etc.) and used by the JWST coronagraphs. We present here the specifications of this standard.

  12. High-level waste tank farm set point document

    SciTech Connect

    Anthony, J.A. III

    1995-01-15

    Setpoints for nuclear safety-related instrumentation are required for actions determined by the design authorization basis. Minimum requirements need to be established for assuring that setpoints are established and held within specified limits. This document establishes the controlling methodology for changing setpoints of all classifications. The instrumentation under consideration involve the transfer, storage, and volume reduction of radioactive liquid waste in the F- and H-Area High-Level Radioactive Waste Tank Farms. The setpoint document will encompass the PROCESS AREA listed in the Safety Analysis Report (SAR) (DPSTSA-200-10 Sup 18) which includes the diversion box HDB-8 facility. In addition to the PROCESS AREAS listed in the SAR, Building 299-H and the Effluent Transfer Facility (ETF) are also included in the scope.

  13. High Level Information Fusion (HLIF) with nested fusion loops

    NASA Astrophysics Data System (ADS)

    Woodley, Robert; Gosnell, Michael; Fischer, Amber

    2013-05-01

    Situation modeling and threat prediction require higher levels of data fusion in order to provide actionable information. Beyond the sensor data and sources the analyst has access to, the use of out-sourced and re-sourced data is becoming common. Through the years, some common frameworks have emerged for dealing with information fusion—perhaps the most ubiquitous being the JDL Data Fusion Group and their initial 4-level data fusion model. Since these initial developments, numerous models of information fusion have emerged, hoping to better capture the human-centric process of data analyses within a machine-centric framework. 21st Century Systems, Inc. has developed Fusion with Uncertainty Reasoning using Nested Assessment Characterizer Elements (FURNACE) to address challenges of high level information fusion and handle bias, ambiguity, and uncertainty (BAU) for Situation Modeling, Threat Modeling, and Threat Prediction. It combines JDL fusion levels with nested fusion loops and state-of-the-art data reasoning. Initial research has shown that FURNACE is able to reduce BAU and improve the fusion process by allowing high level information fusion (HLIF) to affect lower levels without the double counting of information or other biasing issues. The initial FURNACE project was focused on the underlying algorithms to produce a fusion system able to handle BAU and repurposed data in a cohesive manner. FURNACE supports analyst's efforts to develop situation models, threat models, and threat predictions to increase situational awareness of the battlespace. FURNACE will not only revolutionize the military intelligence realm, but also benefit the larger homeland defense, law enforcement, and business intelligence markets.

  14. High-level waste melter alternatives assessment report

    SciTech Connect

    Calmus, R.B.

    1995-02-01

    This document describes the Tank Waste Remediation System (TWRS) High-Level Waste (HLW) Program`s (hereafter referred to as HLW Program) Melter Candidate Assessment Activity performed in fiscal year (FY) 1994. The mission of the TWRS Program is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and encapsulated strontium and cesium isotopic sources) in an environmentally sound, safe, and cost-effective manner. The goal of the HLW Program is to immobilize the HLW fraction of pretreated tank waste into a vitrified product suitable for interim onsite storage and eventual offsite disposal at a geologic repository. Preparation of the encapsulated strontium and cesium isotopic sources for final disposal is also included in the HLW Program. As a result of trade studies performed in 1992 and 1993, processes planned for pretreatment of tank wastes were modified substantially because of increasing estimates of the quantity of high-level and transuranic tank waste remaining after pretreatment. This resulted in substantial increases in needed vitrification plant capacity compared to the capacity of original Hanford Waste Vitrification Plant (HWVP). The required capacity has not been finalized, but is expected to be four to eight times that of the HWVP design. The increased capacity requirements for the HLW vitrification plant`s melter prompted the assessment of candidate high-capacity HLW melter technologies to determine the most viable candidates and the required development and testing (D and T) focus required to select the Hanford Site HLW vitrification plant melter system. An assessment process was developed in early 1994. This document describes the assessment team, roles of team members, the phased assessment process and results, resulting recommendations, and the implementation strategy.

  15. High-level waste program integration within the DOE complex

    SciTech Connect

    Valentine, J.H.; Davis, N.R.; Malone, K.; Schaus, P.S.

    1998-03-01

    Eleven major Department of Energy (DOE) site contractors were chartered by the Assistant Secretary to use a systems engineering approach to develop and evaluate technically defensible cost savings opportunities across the complex. Known as the complex-wide Environmental Management Integration (EMI), this process evaluated all the major DOE waste streams including high level waste (HLW). Across the DOE complex, this waste stream has the highest life cycle cost and is scheduled to take until at least 2035 before all HLW is processed for disposal. Technical contract experts from the four DOE sites that manage high level waste participated in the integration analysis: Hanford, Savannah River Site (SRS), Idaho National Engineering and Environmental Laboratory (INEEL), and West Valley Demonstration Project (WVDP). In addition, subject matter experts from the Yucca Mountain Project and the Tanks Focus Area participated in the analysis. Also, departmental representatives from the US Department of Energy Headquarters (DOE-HQ) monitored the analysis and results. Workouts were held throughout the year to develop recommendations to achieve a complex-wide integrated program. From this effort, the HLW Environmental Management (EM) Team identified a set of programmatic and technical opportunities that could result in potential cost savings and avoidance in excess of $18 billion and an accelerated completion of the HLW mission by seven years. The cost savings, schedule improvements, and volume reduction are attributed to a multifaceted HLW treatment disposal strategy which involves waste pretreatment, standardized waste matrices, risk-based retrieval, early development and deployment of a shipping system for glass canisters, and reasonable, low cost tank closure.

  16. Process Relationships for Evaluating the Role of Light-induced Inactivation of Enterococci at Selected Beaches and Nearby Tributaries of the Great Lakes

    EPA Science Inventory

    One approach to predictive modeling of biological contamination of recreational waters and drinking water sources involves applying process-based models that consider microbial sources, hydrodynamic transport, and microbial fate. Fecal indicator bacteria such as enterococci have ...

  17. Defense High Level Waste Disposal Container System Description

    SciTech Connect

    2000-10-12

    The Defense High Level Waste Disposal Container System supports the confinement and isolation of waste within the Engineered Barrier System of the Monitored Geologic Repository (MGR). Disposal containers are loaded and sealed in the surface waste handling facilities, transferred to the underground through the accesses using a rail mounted transporter, and emplaced in emplacement drifts. The defense high level waste (HLW) disposal container provides long-term confinement of the commercial HLW and defense HLW (including immobilized plutonium waste forms (IPWF)) placed within disposable canisters, and withstands the loading, transfer, emplacement, and retrieval loads and environments. U.S. Department of Energy (DOE)-owned spent nuclear fuel (SNF) in disposable canisters may also be placed in a defense HLW disposal container along with commercial HLW waste forms, which is known as 'co-disposal'. The Defense High Level Waste Disposal Container System provides containment of waste for a designated period of time, and limits radionuclide release. The disposal container/waste package maintains the waste in a designated configuration, withstands maximum handling and rockfall loads, limits the individual canister temperatures after emplacement, resists corrosion in the expected handling and repository environments, and provides containment of waste in the event of an accident. Defense HLW disposal containers for HLW disposal will hold up to five HLW canisters. Defense HLW disposal containers for co-disposal will hold up to five HLW canisters arranged in a ring and one DOE SNF canister in the ring. Defense HLW disposal containers also will hold two Multi-Canister Overpacks (MCOs) and two HLW canisters in one disposal container. The disposal container will include outer and inner cylinders, outer and inner cylinder lids, and may include a canister guide. An exterior label will provide a means by which to identify the disposal container and its contents. Different materials

  18. Spent nuclear fuel project high-level information management plan

    SciTech Connect

    Main, G.C.

    1996-09-13

    This document presents the results of the Spent Nuclear Fuel Project (SNFP) Information Management Planning Project (IMPP), a short-term project that identified information management (IM) issues and opportunities within the SNFP and outlined a high-level plan to address them. This high-level plan for the SNMFP IM focuses on specific examples from within the SNFP. The plan`s recommendations can be characterized in several ways. Some recommendations address specific challenges that the SNFP faces. Others form the basis for making smooth transitions in several important IM areas. Still others identify areas where further study and planning are indicated. The team`s knowledge of developments in the IM industry and at the Hanford Site were crucial in deciding where to recommend that the SNFP act and where they should wait for Site plans to be made. Because of the fast pace of the SNFP and demands on SNFP staff, input and interaction were primarily between the IMPP team and members of the SNFP Information Management Steering Committee (IMSC). Key input to the IMPP came from a workshop where IMSC members and their delegates developed a set of draft IM principles. These principles, described in Section 2, became the foundation for the recommendations found in the transition plan outlined in Section 5. Availability of SNFP staff was limited, so project documents were used as a basis for much of the work. The team, realizing that the status of the project and the environment are continually changing, tried to keep abreast of major developments since those documents were generated. To the extent possible, the information contained in this document is current as of the end of fiscal year (FY) 1995. Programs and organizations on the Hanford Site as a whole are trying to maximize their return on IM investments. They are coordinating IM activities and trying to leverage existing capabilities. However, the SNFP cannot just rely on Sitewide activities to meet its IM requirements

  19. Interventions for Individuals With High Levels of Needle Fear

    PubMed Central

    Noel, Melanie; Taddio, Anna; Antony, Martin M.; Asmundson, Gordon J.G.; Riddell, Rebecca Pillai; Chambers, Christine T.; Shah, Vibhuti

    2015-01-01

    Background: This systematic review evaluated the effectiveness of exposure-based psychological and physical interventions for the management of high levels of needle fear and/or phobia and fainting in children and adults. Design/Methods: A systematic review identified relevant randomized and quasi-randomized controlled trials of children, adults, or both with high levels of needle fear, including phobia (if not available, then populations with other specific phobias were included). Critically important outcomes were self-reported fear specific to the feared situation and stimulus (psychological interventions) or fainting (applied muscle tension). Data were pooled using standardized mean difference (SMD) or relative risk with 95% confidence intervals. Results: The systematic review included 11 trials. In vivo exposure-based therapy for children 7 years and above showed benefit on specific fear (n=234; SMD: −1.71 [95% CI: −2.72, −0.7]). In vivo exposure-based therapy with adults reduced fear of needles posttreatment (n=20; SMD: −1.09 [−2.04, −0.14]) but not at 1-year follow-up (n=20; SMD: −0.28 [−1.16, 0.6]). Compared with single session, a benefit was observed for multiple sessions of exposure-based therapy posttreatment (n=93; SMD: −0.66 [−1.08, −0.24]) but not after 1 year (n=83; SMD: −0.37 [−0.87, 0.13]). Non in vivo e.g., imaginal exposure-based therapy in children reduced specific fear posttreatment (n=41; SMD: −0.88 [−1.7, −0.05]) and at 3 months (n=24; SMD: −0.89 [−1.73, −0.04]). Non in vivo exposure-based therapy for adults showed benefit on specific fear (n=68; SMD: −0.62 [−1.11, −0.14]) but not procedural fear (n=17; SMD: 0.18 [−0.87, 1.23]). Applied tension showed benefit on fainting posttreatment (n=20; SMD: −1.16 [−2.12, −0.19]) and after 1 year (n=20; SMD: −0.97 [−1.91, −0.03]) compared with exposure alone. Conclusions: Exposure-based psychological interventions and applied muscle tension show

  20. CEMENTITIOUS GROUT FOR CLOSING SRS HIGH LEVEL WASTE TANKS - #12315

    SciTech Connect

    Langton, C.; Burns, H.; Stefanko, D.

    2012-01-10

    In 1997, the first two United States Department of Energy (US DOE) high level waste tanks (Tanks 17-F and 20-F: Type IV, single shell tanks) were taken out of service (permanently closed) at the Savannah River Site (SRS). In 2012, the DOE plans to remove from service two additional Savannah River Site (SRS) Type IV high-level waste tanks, Tanks 18-F and 19-F. These tanks were constructed in the late 1950's and received low-heat waste and do not contain cooling coils. Operational closure of Tanks 18-F and 19-F is intended to be consistent with the applicable requirements of the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and will be performed in accordance with South Carolina Department of Health and Environmental Control (SCDHEC). The closure will physically stabilize two 4.92E+04 cubic meter (1.3 E+06 gallon) carbon steel tanks and isolate and stabilize any residual contaminants left in the tanks. The closure will also fill, physically stabilize and isolate ancillary equipment abandoned in the tanks. A Performance Assessment (PA) has been developed to assess the long-term fate and transport of residual contamination in the environment resulting from the operational closure of the F-Area Tank Farm (FTF) waste tanks. Next generation flowable, zero-bleed cementitious grouts were designed, tested, and specified for closing Tanks 18-F and 19-F and for filling the abandoned equipment. Fill requirements were developed for both the tank and equipment grouts. All grout formulations were required to be alkaline with a pH of 12.4 and chemically reduction potential (Eh) of -200 to -400 to stabilize selected potential contaminants of concern. This was achieved by including Portland cement and Grade 100 slag in the mixes, respectively. Ingredients and proportions of cementitious reagents were selected and adjusted, respectively, to support the mass placement strategy developed by closure

  1. Defense High-Level Waste Leaching Mechanisms Program. Final report

    SciTech Connect

    Mendel, J.E.

    1984-08-01

    The Defense High-Level Waste Leaching Mechanisms Program brought six major US laboratories together for three years of cooperative research. The participants reached a consensus that solubility of the leached glass species, particularly solubility in the altered surface layer, is the dominant factor controlling the leaching behavior of defense waste glass in a system in which the flow of leachant is constrained, as it will be in a deep geologic repository. Also, once the surface of waste glass is contacted by ground water, the kinetics of establishing solubility control are relatively rapid. The concentrations of leached species reach saturation, or steady-state concentrations, within a few months to a year at 70 to 90/sup 0/C. Thus, reaction kinetics, which were the main subject of earlier leaching mechanisms studies, are now shown to assume much less importance. The dominance of solubility means that the leach rate is, in fact, directly proportional to ground water flow rate. Doubling the flow rate doubles the effective leach rate. This relationship is expected to obtain in most, if not all, repository situations.

  2. High-Level Performance Modeling of SAR Systems

    NASA Technical Reports Server (NTRS)

    Chen, Curtis

    2006-01-01

    SAUSAGE (Still Another Utility for SAR Analysis that s General and Extensible) is a computer program for modeling (see figure) the performance of synthetic- aperture radar (SAR) or interferometric synthetic-aperture radar (InSAR or IFSAR) systems. The user is assumed to be familiar with the basic principles of SAR imaging and interferometry. Given design parameters (e.g., altitude, power, and bandwidth) that characterize a radar system, the software predicts various performance metrics (e.g., signal-to-noise ratio and resolution). SAUSAGE is intended to be a general software tool for quick, high-level evaluation of radar designs; it is not meant to capture all the subtleties, nuances, and particulars of specific systems. SAUSAGE was written to facilitate the exploration of engineering tradeoffs within the multidimensional space of design parameters. Typically, this space is examined through an iterative process of adjusting the values of the design parameters and examining the effects of the adjustments on the overall performance of the system at each iteration. The software is designed to be modular and extensible to enable consideration of a variety of operating modes and antenna beam patterns, including, for example, strip-map and spotlight SAR acquisitions, polarimetry, burst modes, and squinted geometries.

  3. Wind resource quality affected by high levels of renewables

    DOE PAGES

    Diakov, Victor

    2015-06-17

    For solar photovoltaic (PV) and wind resources, the capacity factor is an important parameter describing the quality of the resource. As the share of variable renewable resources (such as PV and wind) on the electric system is increasing, so does curtailment (and the fraction of time when it cannot be avoided). At high levels of renewable generation, curtailments effectively change the practical measure of resource quality from capacity factor to the incremental capacity factor. The latter accounts only for generation during hours of no curtailment and is directly connected with the marginal capital cost of renewable generators for a givenmore » level of renewable generation during the year. The Western U.S. wind generation is analyzed hourly for a system with 75% of annual generation from wind, and it is found that the value for the system of resources with equal capacity factors can vary by a factor of 2, which highlights the importance of using the incremental capacity factor instead. Finally, the effect is expected to be more pronounced in smaller geographic areas (or when transmission limitations imposed) and less pronounced at lower levels of renewable energy in the system with less curtailment.« less

  4. Wind resource quality affected by high levels of renewables

    SciTech Connect

    Diakov, Victor

    2015-06-17

    For solar photovoltaic (PV) and wind resources, the capacity factor is an important parameter describing the quality of the resource. As the share of variable renewable resources (such as PV and wind) on the electric system is increasing, so does curtailment (and the fraction of time when it cannot be avoided). At high levels of renewable generation, curtailments effectively change the practical measure of resource quality from capacity factor to the incremental capacity factor. The latter accounts only for generation during hours of no curtailment and is directly connected with the marginal capital cost of renewable generators for a given level of renewable generation during the year. The Western U.S. wind generation is analyzed hourly for a system with 75% of annual generation from wind, and it is found that the value for the system of resources with equal capacity factors can vary by a factor of 2, which highlights the importance of using the incremental capacity factor instead. Finally, the effect is expected to be more pronounced in smaller geographic areas (or when transmission limitations imposed) and less pronounced at lower levels of renewable energy in the system with less curtailment.

  5. Vestibular contributions to high-level sensorimotor functions.

    PubMed

    Medendorp, W Pieter; Selen, Luc J P

    2017-02-02

    The vestibular system, which detects motion and orientation of the head in space, is known to be important in controlling gaze to stabilize vision, to ensure postural stability and to provide our sense of self-motion. While the brain's computations underlying these functions are extensively studied, the role of the vestibular system in higher level sensorimotor functions is less clear. This review covers new research on the vestibular influence on perceptual judgments, motor decisions, and the ability to learn multiple motor actions. Guided by concepts such as optimization, inference, estimation and control, we focus on how the brain determines causal relationships between memorized and visual representations in the updating of visual space, and how vestibular, visual and efferent motor information are integrated in the estimation of body motion. We also discuss evidence that these computations involve multiple coordinate representations, some of which can be probed in parietal cortex using neuronal oscillations derived from EEG. In addition, we describe work on decision making during self-motion, showing a clear modulation of bottom-up acceleration signals on decisions in the saccadic system. Finally, we consider the importance of vestibular signals as contextual cues in motor learning and recall. Taken together, these results emphasize the impact of vestibular information on high-level sensorimotor functions, and identify future directions for theoretical, behavioral, and neurophysiological investigations.

  6. Control of high level radioactive waste-glass melters

    SciTech Connect

    Bickford, D.F.; Choi, A.S.

    1991-01-01

    Slurry Fed Melters (SFM) are being developed in the United States, Europe and Japan for the conversion of high-level radioactive waste to borosilicate glass for permanent disposal. The high transition metal, noble metal, nitrate, organic, and sulfate contents of these wastes lead to unique melter redox control requirements. Pilot waste-glass melter operations have indicated the possibility of nickel sulfide or noble-metal fission-product accumulation on melter floors, which can lead to distortion of electric heating patterns, and decrease melter life. Sulfide formation is prevented by control of the redox chemistry of the melter feed. The redox state of waste-glass melters is determined by balance between the reducing potential of organic compounds in the feed, and the oxidizing potential of gases above the melt, and nitrates and polyvalent elements in the waste. Semiquantitative models predicting limitations of organic content have been developed based on crucible testing. Computerized thermodynamic computations are being developed to predict the sequence and products of redox reactions and is assessing process variations. Continuous melter test results have been compared to improved computer staged-thermodynamic-models of redox behavior. Feed chemistry control to prevent sulfide and moderate noble metal accumulations are discussed. 17 refs., 3 figs.

  7. Potential for erosion corrosion of SRS high level waste tanks

    SciTech Connect

    Zapp, P.E.

    1994-01-01

    SRS high-level radioactive waste tanks will not experience erosion corrosion to any significant degree during slurry pump operations. Erosion corrosion in carbon steel structures at reported pump discharge velocities is dominated by electrochemical (corrosion) processes. Interruption of those processes, as by the addition of corrosion inhibitors, sharply reduces the rate of metal loss from erosion corrosion. The well-inhibited SRS waste tanks have a near-zero general corrosion rate, and therefore will be essentially immune to erosion corrosion. The experimental data on carbon steel erosion corrosion most relevant to SRS operations was obtained at the Hanford Site on simulated Purex waste. A metal loss rate of 2.4 mils per year was measured at a temperature of 102 C and a slurry velocity comparable to calculated SRS slurry velocities on ground specimens of the same carbon steel used in SRS waste tanks. Based on these data and the much lower expected temperatures, the metal loss rate of SRS tanks under waste removal and processing conditions should be insignificant, i.e. less than 1 mil per year.

  8. Metrics associated with NIH funding: a high-level view

    PubMed Central

    Jordan, Paul

    2011-01-01

    Objective To introduce the availability of grant-to-article linkage data associated with National Institutes of Health (NIH) grants and to perform a high-level analysis of the publication outputs and impacts associated with those grants. Design Articles were linked to the grants they acknowledge using the grant acknowledgment strings in PubMed using a parsing and matching process as embodied in the NIH Scientific Publication Information Retrieval & Evaluation System system. Additional data from PubMed and citation counts from Scopus were added to the linkage data. The data comprise 2 572 576 records from 1980 to 2009. Results The data show that synergies between NIH institutes are increasing over time; 29% of current articles acknowledge grants from multiple institutes. The median time lag to publication for a new grant is 3 years. Each grant contributes to approximately 1.7 articles per year, averaged over all grant types. Articles acknowledging US Public Health Service (PHS, which includes NIH) funding are cited twice as much as US-authored articles acknowledging no funding source. Articles acknowledging both PHS funding and a non-US government funding source receive on average 40% more citations that those acknowledging PHS funding sources alone. Conclusion The US PHS is effective at funding research with a higher-than-average impact. The data are amenable to further and much more detailed analysis. PMID:21527408

  9. Hemipelvectomy: high-level amputation surgery and prosthetic rehabilitation.

    PubMed

    Houdek, Matthew T; Kralovec, Michael E; Andrews, Karen L

    2014-07-01

    The hemipelvectomy, most commonly performed for pelvic tumor resection, is one of the most technically demanding and invasive surgical procedures performed today. Adequate soft tissue coverage and wound complications after hemipelvectomy are important considerations. Rehabilitation after hemipelvectomy is optimally managed by a multidisciplinary integrated team. Understanding the functional outcomes for this population assists the rehabilitation team to counsel patients, plan goals, and determine discharge needs. The most important rehabilitation goal is the optimal restoration of the patient's functional independence. Factors such as age, sex, etiology, level of amputation, and general health play important roles in determining prosthetic use. The three main criteria for successful prosthetic rehabilitation of patients with high-level amputation are comfort, function, and cosmesis. Recent advances in hip and knee joints have contributed to increased function. Prosthetic use after hemipelvectomy improves balance and decreases the need for a gait aid. Using a prosthesis helps maintain muscle strength and tone, cardiovascular health, and functional mobility. With new advances in prosthetic components, patients are choosing to use their prostheses for primary mobility.

  10. ATW system impact on high-level waste

    SciTech Connect

    Arthur, E.D.

    1992-12-01

    This report discusses the Accelerator Transmutation of Waste (ATW) concept which aims at destruction of key long-lived radionuclides in high-level nuclear waste (HLW), both fission products and actinides. This focus makes it different from most other transmutation concepts which concentrate primarily on actinide burning. The ATW system uses an accelerator-driven, sub-critical assembly to create an intense thermal neutron environment for radionuclide transmutation. This feature allows rapid transmutation under low-inventory system conditions, which in turn, has a direct impact on the size of chemical separations and materials handling components of the system. Inventories in ATW are factors of eight to thirty times smaller than reactor systems of equivalent thermal power. Chemical separations systems are relatively small in scale and can be optimized to achieve high decontamination factors and minimized waste streams. The low-inventory feature also directly impacts material amounts remaining in the system at its end of life. In addition to its low-inventory operation, the accelerator-driven neutron source features of ATW are key to providing a sufficient level of neutrons to allow transmutation of long-lived fission products.

  11. High-level fluorescence labeling of gram-positive pathogens.

    PubMed

    Aymanns, Simone; Mauerer, Stefanie; van Zandbergen, Ger; Wolz, Christiane; Spellerberg, Barbara

    2011-01-01

    Fluorescence labeling of bacterial pathogens has a broad range of interesting applications including the observation of living bacteria within host cells. We constructed a novel vector based on the E. coli streptococcal shuttle plasmid pAT28 that can propagate in numerous bacterial species from different genera. The plasmid harbors a promoterless copy of the green fluorescent variant gene egfp under the control of the CAMP-factor gene (cfb) promoter of Streptococcus agalactiae and was designated pBSU101. Upon transfer of the plasmid into streptococci, the bacteria show a distinct and easily detectable fluorescence using a standard fluorescence microscope and quantification by FACS-analysis demonstrated values that were 10-50 times increased over the respective controls. To assess the suitability of the construct for high efficiency fluorescence labeling in different gram-positive pathogens, numerous species were transformed. We successfully labeled Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus dysgalactiae subsp. equisimilis, Enterococcus faecalis, Enterococcus faecium, Streptococcus mutans, Streptococcus anginosus and Staphylococcus aureus strains utilizing the EGFP reporter plasmid pBSU101. In all of these species the presence of the cfb promoter construct resulted in high-level EGFP expression that could be further increased by growing the streptococcal and enterococcal cultures under high oxygen conditions through continuous aeration.

  12. High Level Waste Feed Certification in Hanford Double Shell Tanks

    SciTech Connect

    Thien, Micheal G.; Wells, Beric E.; Adamson, Duane J.

    2010-03-01

    The ability to effectively mix, sample, certify, and deliver consistent batches of High Level Waste (HLW) feed from the Hanford Double Shell Tanks (DST) to the Waste Treatment and Immobilization Plant (WTP) presents a significant mission risk with potential to impact mission length and the quantity of HLW glass produced. DOE’s River Protection Project (RPP) mission modeling and WTP facility modeling assume that individual 3785 cubic meter (1 million gallon) HLW feed tanks are homogenously mixed, representatively sampled, and consistently delivered to the WTP. It has been demonstrated that homogenous mixing of HLW sludge in Hanford DSTs is not likely achievable with the baseline design thereby causing representative sampling and consistent feed delivery to be more difficult. Inconsistent feed to the WTP could cause additional batch to batch operational adjustments that reduces operating efficiency and has the potential to increase the overall mission length. The Hanford mixing and sampling demonstration program will identify DST mixing performance capability, will evaluate representative sampling techniques, and will estimate feed batch consistency. An evaluation of demonstration program results will identify potential mission improvement considerations that will help ensure successful mission completion. This paper will discuss the history, progress, and future activities that will define and mitigate the mission risk.

  13. Identification of areas with high levels of untreated dental caries.

    PubMed

    Ellwood, R P; O'Mullane, D M

    1996-02-01

    In order to examine the geographical variation of dental health within 10 county districts in North Wales, 3538 children were examined. The associations between three demographic indicators, based on the 1981 OPCS census, and dental health outcomes were assessed for electoral wards within the county districts. The Townsend and Jarman indices were the first two indicators employed and the third was based on a mathematical model representing the variation in the mean number of untreated decayed surfaces per person for the wards. This model was developed using the children examined in the five most westerly county districts. Using the data derived from the five most easterly county districts, the three indicators were assessed. All three showed strong correlations (r > or = 0.88) with dental health. These results indicate that measures of dental health based on large administrative units may obscure variation within them. It is concluded that geographical methods of this type may be useful for targeting dental resources at small areas with high levels of need.

  14. Why consider subseabed disposal of high-level nuclear waste

    SciTech Connect

    Heath, G. R.; Hollister, C. D.; Anderson, D. R.; Leinen, M.

    1980-01-01

    Large areas of the deep seabed warrant assessment as potential disposal sites for high-level radioactive waste because: (1) they are far from seismically and tectonically active lithospheric plate boundaries; (2) they are far from active or young volcanos; (3) they contain thick layers of very uniform fine-grained clays; (4) they are devoid of natural resources likely to be exploited in the forseeable future; (5) the geologic and oceanographic processes governing the deposition of sediments in such areas are well understood, and are remarkably insensitive to past oceanographic and climatic changes; and (6) sedmentary records of tens of millions of years of slow, uninterrupted deposition of fine grained clay support predictions of the future stability of such sites. Data accumulated to date on the permeability, ion-retardation properties, and mechanical strength of pelagic clay sediments indicate that they can act as a primary barrier to the escape of buried nuclides. Work in progress should determine within the current decade whether subseabed disposal is environmentally acceptable and technically feasible, as well as address the legal, political and social issues raised by this new concept.

  15. Pupil responses to high-level image content.

    PubMed

    Naber, Marnix; Nakayama, Ken

    2013-05-17

    The link between arousal and pupil dilation is well studied, but it is less known that other cognitive processes can trigger pupil responses. Here we present evidence that pupil responses can be induced by high-level scene processing, independent of changes in low-level features or arousal. In Experiment 1, we recorded changes in pupil diameter of observers while they viewed a variety of natural scenes with or without a sun that were presented either upright or inverted. Image inversion had the strongest effect on the pupil responses. The pupil constricted more to the onset of upright images as compared to inverted images. Furthermore, the amplitudes of pupil constrictions to viewing images containing a sun were larger relative to control images. In Experiment 2, we presented cartoon versions of upright and inverted pictures that included either a sun or a moon. The image backgrounds were kept identical across conditions. Similar to Experiment 1, upright images triggered pupil constrictions with larger amplitudes than inverted images and images of the sun evoked greater pupil contraction than images of the moon. We suggest that the modulations of pupil responses were due to higher-level interpretations of image content.

  16. Ultrafilter Conditions for High Level Waste Sludge Processing

    SciTech Connect

    Geeting, John GH; Hallen, Richard T.; Peterson, Reid A.

    2006-08-28

    An evaluation of the optimal filtration conditions was performed based on test data obtained from filtration of a High Level Waste Sludge sample from the Hanford tank farms. This evaluation was performed using the anticipated configuration for the Waste Treatment Plant at the Hanford site. Testing was performed to identify the optimal pressure drop and cross flow velocity for filtration at both high and low solids loading. However, this analysis indicates that the actual filtration rate achieved is relatively insensitive to these conditions under anticipated operating conditions. The maximum filter flux was obtained by adjusting the system control valve pressure from 400 to 650 kPa while the filter feed concentration increased from 5 to 20 wt%. However, operating the system with a constant control valve pressure drop of 500 kPa resulted in a less than 1% reduction in the average filter flux. Also note that allowing the control valve pressure to swing as much as +/- 20% resulted in less than a 5% decrease in filter flux.

  17. High-level simulation of JWST event-driven operations

    NASA Astrophysics Data System (ADS)

    Henry, R.; Kinzel, W.

    2012-09-01

    The James Webb Space Telescope (JWST) has an event-driven architecture: an onboard Observation Plan Executive (OPE) executes an Observation Plan (OP) consisting of a sequence of observing units (visits). During normal operations, ground action to update the OP is only expected to be necessary about once a week. This architecture is designed to tolerate uncertainty in visit duration, and occasional visit failures due to inability to acquire guide stars, without creating gaps in the observing timeline. The operations concept is complicated by the need for occasional scheduling of timecritical science and engineering visits that cannot tolerate much slippage without inducing gaps, and also by onboard momentum management. A prototype Python tool called the JWST Observation Plan Execution Simulator (JOPES) has recently been developed to simulate OP execution at a high level and analyze the response of the Observatory and OPE to both nominal and contingency scenarios. Incorporating both deterministic and stochastic behavior, JOPES has potential to be a powerful tool for several purposes: requirements analysis, system verification, systems engineering studies, and test data generation. It has already been successfully applied to a study of overhead estimation bias: whether to use conservative or average-case estimates for timing components that are inherently uncertain, such as those involving guide-star acquisition. JOPES is being enhanced to support interfaces to the operational Proposal Planning Subsystem (PPS) now being developed, with the objective of "closing the loop" between testing and simulation by feeding simulated event logs back into the PPS.

  18. The GRAVITY instrument software/high-level software

    NASA Astrophysics Data System (ADS)

    Burtscher, Leonard; Wieprecht, Ekkehard; Ott, Thomas; Kok, Yitping; Yazici, Senol; Anugu, Narsireddy; Dembet, Roderick; Fedou, Pierre; Lacour, Sylvestre; Ott, Jürgen; Paumard, Thibaut; Lapeyrere, Vincent; Kervella, Pierre; Abuter, Roberto; Pozna, Eszter; Eisenhauer, Frank; Blind, Nicolas; Genzel, Reinhard; Gillessen, Stefan; Hans, Oliver; Haug, Marcus; Haussmann, Frank; Kellner, Stefan; Lippa, Magdalena; Pfuhl, Oliver; Sturm, Eckhard; Weber, Johannes; Amorim, Antonio; Brandner, Wolfgang; Rousselet-Perraut, Karine; Perrin, Guy S.; Straubmeier, Christian; Schöller, Markus

    2014-07-01

    GRAVITY is the four-beam, near-infrared, AO-assisted, fringe tracking, astrometric and imaging instrument for the Very Large Telescope Interferometer (VLTI). It is requiring the development of one of the most complex instrument software systems ever built for an ESO instrument. Apart from its many interfaces and interdependencies, one of the most challenging aspects is the overall performance and stability of this complex system. The three infrared detectors and the fast reflective memory network (RMN) recorder contribute a total data rate of up to 20 MiB/s accumulating to a maximum of 250 GiB of data per night. The detectors, the two instrument Local Control Units (LCUs) as well as the five LCUs running applications under TAC (Tools for Advanced Control) architecture, are interconnected with fast Ethernet, RMN fibers and dedicated fiber connections as well as signals for the time synchronization. Here we give a simplified overview of all subsystems of GRAVITY and their interfaces and discuss two examples of high-level applications during observations: the acquisition procedure and the gathering and merging of data to the final FITS file.

  19. The LHCb Data Acquisition and High Level Trigger Processing Architecture

    NASA Astrophysics Data System (ADS)

    Frank, M.; Gaspar, C.; Jost, B.; Neufeld, N.

    2015-12-01

    The LHCb experiment at the LHC accelerator at CERN collects collisions of particle bunches at 40 MHz. After a first level of hardware trigger with an output rate of 1 MHz, the physically interesting collisions are selected by running dedicated trigger algorithms in the High Level Trigger (HLT) computing farm. This farm consists of up to roughly 25000 CPU cores in roughly 1750 physical nodes each equipped with up to 4 TB local storage space. This work describes the LHCb online system with an emphasis on the developments implemented during the current long shutdown (LS1). We will elaborate the architecture to treble the available CPU power of the HLT farm and the technicalities to determine and verify precise calibration and alignment constants which are fed to the HLT event selection procedure. We will describe how the constants are fed into a two stage HLT event selection facility using extensively the local disk buffering capabilities on the worker nodes. With the installed disk buffers, the CPU resources can be used during periods of up to ten days without beams. These periods in the past accounted to more than 70% of the total time.

  20. Prevalence of Vancomycin-Resistant Enterococci in Fecal Samples from Hospitalized Patients and Nonhospitalized Controls in a Cattle-Rearing Area of France

    PubMed Central

    Gambarotto, Karine; Ploy, Marie-Cécile; Turlure, Pascal; Grélaud, Carole; Martin, Christian; Bordessoule, Dominique; Denis, Francois

    2000-01-01

    Vancomycin-resistant enterococci (VRE) have emerged as nosocomial pathogens over the last decade, but little is known about their epidemiology. We report on the prevalence of VRE fecal colonization on the basis of a prospective study among patients hospitalized in a hematology intensive care unit and among nonhospitalized subjects living in the local community. A total of 243 rectal swabs from hematology patients and 169 stool samples from the control group were inoculated onto bile-esculin agar plates with and without 6 mg of vancomycin per liter and into an enrichment bile-esculin broth supplemented with 4 mg of vancomycin per liter. A total of 37% of the hospitalized patients and 11.8% of the subjects from the community were found to be VRE carriers. A total of 65 VRE strains were isolated: 12 (18.5%) E. faecium, 46 (70.7%) E. gallinarum, and 7 (10.8%) E. casseliflavus strains. No E. faecalis strains were detected. All the E. faecium strains were of the vanA genotype. Molecular typing by pulsed-field gel electrophoresis revealed a different pattern for each vanA VRE strain that originated from an individual subject. To our knowledge, this is the first study to be carried out in a cattle-rearing region of France. It reports a higher VRE prevalence than that reported in previous European or U.S. studies. A partial explanation is the use of an enrichment broth step which enabled detection of strains which would otherwise have been missed, but the fact that subjects and patients were recruited from a predominantly agricultural area where vancomycin-related antibiotics have recently been used in animal husbandry could also contribute to the high levels of VRE in patients and subjects alike. PMID:10655356

  1. Historical Associations of Molecular Measurements of Escherichia coli and Enterococci to Anthropogenic Activities and Climate Variables in Freshwater Sediment Cores.

    PubMed

    Brooks, Yolanda M; Baustian, Melissa M; Baskaran, Mark; Ostrom, Nathaniel E; Rose, Joan B

    2016-07-05

    This study investigated the long-term associations of anthropogenic (sedimentary P, C, and N concentrations, and human population in the watershed), and climatic variables (air temperature, and river discharge) with Escherichia coli uidA and enterococci 23S rRNA concentrations in sediment cores from Anchor Bay (AB) in Lake St. Clair, and near the mouth of the Clinton River (CR), Michigan. Calendar year was estimated from vertical abundances of (137)Cs. The AB and CR cores spanned c.1760-2012 and c.1895-2012, respectively. There were steady state concentrations of enterococci in AB during c.1760-c.1860 and c.1910-c.2003 at ∼0.1 × 10(5) and ∼2.0 × 10(5) cell equivalents (CE) per g-dry wt, respectively. Enterococci concentrations in CR increased toward present day, and ranged from ∼0.03 × 10(5) to 9.9 × 10(5) CE/g-dry wt. The E. coli concentrations in CR and AB increased toward present day, and ranged from 0.14 × 10(7) to 1.7 × 10(7) CE/g-dry wt, and 1.8 × 10(6) to 8.5 × 10(6) CE/g-dry wt, respectively. Enterococci was associated with population and river discharge, while E. coli was associated with population, air temperature, and N and C concentrations (p < 0.05). Sediments retain records of the abundance of fecal indicator bacteria, and offer a way to evaluate responses to increased population, nutrient loading, and environmental policies.

  2. Enhancing the Anti-Enterococci Activity of Different Antibiotics by Combining With Metal Oxide Nanoparticles

    PubMed Central

    Iram, Saira; Akbar Khan, Jawad; Aman, Nargis; Nadhman, Akhtar; Zulfiqar, Zikra; Arfat Yameen, Muhammad

    2016-01-01

    Background Enterococci have emerged as more virulent and multidrug-resistant in community and hospital settings. The emergence of vancomycin resistant enterococci (VRE) in hospitals has posed a serious threat to public health. The widespread use of antibiotics to treat VRE infections has resulted in the development of resistant forms of these organisms. Objectives Present study deals with the efficacy of antibiotic-nanoparticle combination against clinical isolates of VRE. This study has effectively evaluated the anti-enterococcal activity of metallic nanoparticles and their combination with antibiotics with the aim to search for new biocidal combinations. Materials and Methods Initially, the isolates were identified by various biochemical tests and also by PCR, targeting ddl, vanA and vanB genes. Antibiotic susceptibility testing was carried out by disc diffusion method. Minimum inhibitory concentration (MIC) of both antibiotics and metal nanoparticles against VRE was done using broth dilution method. On the basis of MICs, a combination of both antibiotics and nanoparticles was used by physical mixing of antibiotics and different concentrations of nanoparticles. Results The MIC of metal nanoparticles were found in the range of 0.31 - 30 mM. The combination of both antibiotics and nanoparticles has effectively reduced the MICs of ciprofloxacin from 16 - 256 μg/mL to 2 - 16 μg/mL, erythromycin 1024 - 2048 μg/mL to 128 - 512 μg/mL, methicillin 32 - 256 μg/mL to 8 - 64 μg/mL and vancomycin 2 - 512 μg/mL to 0.5 - 64 μg/mL. Conclusions Among the nanoparticles, ZnO was found as a potent metallic nanoparticle which effectively reduced the MIC upon combination with the antibiotics. The combination exhibited enhanced bactericidal activity against multidrug resistant clinical strains of VRE with dose dependency. Further extensive study on this aspect can prove their beneficial clinical use against resistant pathogens to combat increasing resistance to antibiotics

  3. Impacts of Stormwater Management Measures on E. coli and Enterococci Populations in Stormwater Effluent

    NASA Astrophysics Data System (ADS)

    Wildey, R. A.; Ballestero, T. P.; Roseen, R. M.; Houle, J.

    2005-05-01

    In our efforts to improve the quality of runoff entering our streams and waterways, stormwater management measures (or BMPs) are being implemented at a rapid pace. Usually designed to treat one or more specific types of contamination or loading, these measures may have unintended consequences that are not well understood. One issue that has not been fully explored is the potential effect these systems have on microbial contamination of the treated runoff. This study evaluates 11 types of treatment systems and their impact on E. coli and Enterococci contamination. Recent research has demonstrated that near-shore sediment may act as a continuous source of bacterial loading in the overlying waters, rather than bacterial loading being solely a temporal, storm-driven phenomenon. Similarly, stormwater management measures that utilize a soil media for filtration or incorporate a sediment sump may also provide conditions conducive to the incubation of fecal coliforms that can then be released into the environment during runoff events. Following with EPA regulatory guidelines for receiving waters, E. coli and Enterococci are used as surrogates for the presence of other potential disease-causing pathogens typically associated with mammalian and avian enteric bacteria. The stormwater management measures being investigated include: subsurface infiltration, surface sand filter, standard detention pond, bioretention area, hydrodynamic separation, subsurface gravel wetland, street sweeping, and vegetated swale. An adjacent porous parking area and a standard asphalt lot that drains to a tree filter are similarly monitored. Influent is supplied by runoff generated by a 9-acre commuter parking lot at the University of New Hampshire in Durham, NH. This influent is distributed equally to the different treatment devices that operate in parallel. Water quality parameters (DO, pH, specific conductivity, temperature) and flow are continuously monitored upstream from the distribution

  4. Qualification of Innovative High Level Waste Pipeline Unplugging Technologies

    SciTech Connect

    McDaniel, D.; Gokaltun, S.; Varona, J.; Awwad, A.; Roelant, D.; Srivastava, R.

    2008-07-01

    In the past, some of the pipelines have plugged during high level waste (HLW) transfers resulting in schedule delays and increased costs. Furthermore, pipeline plugging has been cited by the 'best and brightest' technical review as one of the major issues that can result in unplanned outages at the Waste Treatment Plant causing inconsistent operation. As the DOE moves toward a more active high level waste retrieval, the site engineers will be faced with increasing cross-site pipeline waste slurry transfers that will result in increased probability of a pipeline getting plugged. Hence, availability of a pipeline unplugging tool/technology is crucial to ensure smooth operation of the waste transfers and in ensuring tank farm cleanup milestones are met. FIU had earlier tested and evaluated various unplugging technologies through an industry call. Based on mockup testing, two technologies were identified that could withstand the rigors of operation in a radioactive environment and with the ability to handle sharp 90 elbows. We present results of the second phase of detailed testing and evaluation of pipeline unplugging technologies and the objective is to qualify these pipeline unplugging technologies for subsequent deployment at a DOE facility. The current phase of testing and qualification comprises of a heavily instrumented 3-inch diameter (full-scale) pipeline facilitating extensive data acquisition for design optimization and performance evaluation, as it applies to three types of plugs atypical of the DOE HLW waste. Furthermore, the data from testing at three different lengths of pipe in conjunction with the physics of the process will assist in modeling the unplugging phenomenon that will then be used to scale-up process parameters and system variables for longer and site typical pipe lengths, which can extend as much as up to 19,000 ft. Detailed information resulting from the testing will provide the DOE end-user with sufficient data and understanding of the

  5. Cultivation of vancomycin-resistant enterococci and methicillin-resistant staphylococci from input and output samples of German biogas plants.

    PubMed

    Glaeser, Stefanie P; Sowinsky, Olivia; Brunner, Jana S; Dott, Wolfgang; Kämpfer, Peter

    2016-03-01

    Vancomycin-resistant enterococci (VRE) and methicillin-resistant staphylococci (MRS) were detected in two mesophilic German biogas plants (BGPs) using selective pre-enrichment methods combined with cultivation on CHROMagar media and antibiotic resistance gene screening. Genetic fingerprinting and 16S rRNA gene sequencing showed the presence of enterococci isolated by the VRE selective cultivation (67 isolates) in input and output samples of BGPs. In contrast, MRS (44 isolates) were detected in input, but in none of the output samples. Enterococcus isolates showed highest 16S rRNA gene sequence similarity (>99.8%) to E. lemanii, E. casseliflavus/E. gallinarium or E. devriesei/E. pseudoavium/E. viikkiensis and carried vanA, vanB and/or vanC1 genes. Enterococcus faecium and E. faecalis VRE were not detected, but isolates closely related to those species (>99.9% 16S rRNA gene sequence similarity) were detected by the MRS selective cultivation methods. Staphylococcus isolates shared highest 16S rRNA gene sequence similarity (>99.9%) with S. haemolyticus, S. lentus and S. sciuri and carried mecA genes. Methicillin-resistant S. aureus (MRSA) were not detected. In summary, manure from livestock husbandry contained both, VRE and MRS. VRE were also detected in output samples, indicating that enterococci with vancomycin resistance genes could be release into the environment by the application of BGP output material as biofertilizers.

  6. The Emergence of Linezolid Resistance among Enterococci in Intestinal Microbiota of Treated Patients Is Unrelated to Individual Pharmacokinetic Characteristics

    PubMed Central

    Nguyen, T. T.; Defrance, G.; Massias, L.; Alavoine, L.; Lefort, A; Noel, V.; Senneville, E.; Doucet-Populaire, F.; Mentré, F.; Andremont, A.; Duval, X.

    2014-01-01

    Linezolid is an antimicrobial agent for the treatment of multiresistant Gram-positive infections. We assessed the impact of linezolid on the microbiota and the emergence of resistance and investigated its relationship with plasma pharmacokinetics of the antibiotic. Twenty-eight patients were treated for the first time with linezolid administered orally (n = 17) or parenterally (n = 11) at 600 mg twice a day. Linezolid plasma pharmacokinetic analysis was performed on day 7. Colonization by fecal enterococci, pharyngeal streptococci, and nasal staphylococci were assessed using selective media with or without supplemental linezolid. The resistance to linezolid was characterized. The treatment led to a decrease of enterococci, staphylococci, and streptococci in the fecal (P = 0.03), nasal, and pharyngeal (P < 0.01) microbiotas. The appearance of resistant strains was observed only in enterococci from the fecal microbiota between the 7th and 21st days of treatment in four patients (14.3%). The resistance was mainly due for the first time to the mutation G2447T in the 23S rRNA gene. No pharmacokinetic parameters were significantly different between the patients, regardless of the appearance of resistance. The emergence of linezolid resistance during treatment was observed only in the intestinal microbiota and unrelated to pharmacokinetic parameters. However, colonization by Gram-positive bacteria was reduced as a result of treatment in all microbiotas. PMID:24566182

  7. Molecular characterization of antibiotic resistance in enterococci recovered from seagulls (Larus cachinnans) representing an environmental health problem.

    PubMed

    Radhouani, Hajer; Igrejas, Gilberto; Pinto, Luís; Gonçalves, Alexandre; Coelho, Céline; Rodrigues, Jorge; Poeta, Patrícia

    2011-08-01

    Antimicrobial resistance and the mechanisms implicated were studied in 54 enterococci recovered from 57 seagull fecal samples. Almost 78% of the recovered enterococci showed resistance against one or more antibiotics and these isolates were identified to the species level. E. faecium was the most prevalent species (52.4%). High percentages of erythromycin and tetracycline resistances were found among our isolates (95.2%), and lower percentages were identified to other antibiotics. Most of the tetracycline-resistant strains carried the tet(M) and/or tet(L) genes. Genes associated with Tn916/Tn1545 and/or Tn5397 transposons were detected in 45% of tetracycline-resistant isolates. The erm(B) gene was detected in 65% of erythromycin-resistant isolates. The vat(D) and vat(E) genes were present in 5.9% and 11.8% of quinupristin/dalfopristin-resistant isolates, respectively. The ant(6)-Ia gene was identified in 57.1% of streptomycin-resistant isolates. All nine kanamycin-resistant isolates carried the aph(3)'-IIIa gene. The cat(A) gene was found in two chloramphenicol-resistant isolates. Seagulls should be considered a risk species for spreading in the environment antimicrobial resistant enterococci and can serve as a sentinel for antibiotic pressure from the surrounding farm and urban setting.

  8. VanA-type vancomycin-resistant enterococci in equine and swine rectal swabs and in human clinical samples.

    PubMed

    de Niederhäusern, Simona; Sabia, Carla; Messi, Patrizia; Guerrieri, Elisa; Manicardi, Giuliano; Bondi, Moreno

    2007-09-01

    Vancomycin-resistant enterococci (VRE) in healthy people and in food-producing animals seems to be quite common in Europe. The existence of this community reservoir of VRE has been associated with the massive use of avoparcin in animal husbandry. Eight years after the avoparcin ban in Europe, we investigated the incidence of VanA enterococci, their resistance patterns, and the mobility of their glycopeptide-resistance determinants in a sampling of animal rectal swabs and clinical specimens. A total of 259 enterococci isolated from equine, swine, and clinical samples were subcultured on KF-streptococcus agar (Difco Laboratories, Detroit, MI) supplemented with vancomycin and teicoplanin; 7 (6.7%), 10 (16%), and 8 (8.6%) respectively were found to be glycopeptides resistant (VanA phenotype). Slight differences in antimicrobial resistance patterns resulted among VRE recovered from the different sources. Polymerase chain reaction amplification demonstrated the presence of the vanA gene cluster and its extrachromosomal location in VRE plasmid DNA. VanA resistance was transferred in 7 out of 25 mating experiments, 4 with clinical, 2 with swine, and only 1 with equine donors. The conjugative plasmids of animal strains showed a high homology in the restriction profiles, unlike plasmids of clinical microrganisms. Our observations confirmed the possible horizontal transfer of VanA plasmids across different strains and, consequently, the diffusion of the vancomycin-resistance determinants.

  9. Effect of mesophilic lactobacilli and enterococci adjunct cultures on the final characteristics of a microfiltered milk Swiss-type cheese.

    PubMed

    Bouton, Yvette; Buchin, Solange; Duboz, Gabriel; Pochet, Sylvie; Beuvier, Eric

    2009-04-01

    The effect of four associations of adjunct cultures composed of mesophilic lactobacilli and enterococci, either solely or combined, on the microbiological, biochemical and sensory characteristics of Swiss-type cheese made using microfiltered cows' milk and supplemented with propionibacteria was studied. The global pattern of growth was similar to that generally observed in raw milk cheese and interactions between microflora were highlighted during ripening. Enterococci, which negatively affected the survival of streptococci starters, seemed to play a limited role in the formation of volatile compounds, probably due to their low levels throughout ripening. On the contrary, mesophilic lactobacilli, which affected the evolution of propionibacteria, enterococci and L. delbrueckii subsp. lactis starter counts, modified free amino acid content, production of volatile compounds and organoleptic properties of mature cheese. This population appeared to be of major importance in the formation of cheese flavor as it was positively related to numerous potential flavor compounds such as alcohols and their corresponding esters, acetaldehyde and 4-methyl-4-heptanone. The original mesophilic lactobacilli present in milk could play an important role in the sensorial diversity of raw milk Swiss-type cheeses such as Comte.

  10. High Levels of Molecular Chlorine found in the Arctic Atmosphere

    NASA Astrophysics Data System (ADS)

    Liao, J.; Huey, L. G.; Liu, Z.; Tanner, D.; Cantrell, C. A.; Orlando, J. J.; Flocke, F. M.; Shepson, P. B.; Weinheimer, A. J.; Hall, S. R.; Beine, H.; Wang, Y.; Ingall, E. D.; Thompson, C. R.; Hornbrook, R. S.; Apel, E. C.; Fried, A.; Mauldin, L.; Smith, J. N.; Staebler, R. M.; Neuman, J. A.; Nowak, J. B.

    2014-12-01

    Chlorine radicals are a strong atmospheric oxidant, particularly in polar regions where levels of hydroxyl radicals can be quite low. In the atmosphere, chlorine radicals expedite the degradation of methane and tropospheric ozone and the oxidation of mercury to more toxic forms. Here, we present direct measurements of molecular chlorine levels in the Arctic marine boundary layer in Barrow, Alaska, collected in the spring of 2009 over a six-week period using chemical ionization mass spectrometry. We detected high levels of molecular chlorine of up to 400 pptv. Concentrations peaked in the early morning and late afternoon and fell to near-zero levels at night. Average daytime molecular chlorine levels were correlated with ozone concentrations, suggesting that sunlight and ozone are required for molecular chlorine formation. Using a time-dependent box model, we estimated that the chlorine radicals produced from the photolysis of molecular chlorine on average oxidized more methane than hydroxyl radicals and enhanced the abundance of short-lived peroxy radicals. Elevated hydroperoxyl radical levels, in turn, promoted the formation of hypobromous acid, which catalyzed mercury oxidation and the breakdown of tropospheric ozone. Therefore, we propose that molecular chlorine exerts a significant effect on the atmospheric chemistry in the Arctic. While the formation mechanisms of molecular chlorine are not yet understood, the main potential sources of chlorine include snowpack, sea salt, and sea ice. There is recent evidence of molecular halogen (Br2 and Cl2) formation in the Arctic snowpack. The coverage and composition of the snow may control halogen chemistry in the Arctic. Changes of sea ice and snow cover in the changing climate may affect air-snow-ice interaction and have a significant impact on the levels of radicals, ozone, mercury and methane in the Arctic troposphere.

  11. Engineering neural systems for high-level problem solving.

    PubMed

    Sylvester, Jared; Reggia, James

    2016-07-01

    There is a long-standing, sometimes contentious debate in AI concerning the relative merits of a symbolic, top-down approach vs. a neural, bottom-up approach to engineering intelligent machine behaviors. While neurocomputational methods excel at lower-level cognitive tasks (incremental learning for pattern classification, low-level sensorimotor control, fault tolerance and processing of noisy data, etc.), they are largely non-competitive with top-down symbolic methods for tasks involving high-level cognitive problem solving (goal-directed reasoning, metacognition, planning, etc.). Here we take a step towards addressing this limitation by developing a purely neural framework named galis. Our goal in this work is to integrate top-down (non-symbolic) control of a neural network system with more traditional bottom-up neural computations. galis is based on attractor networks that can be "programmed" with temporal sequences of hand-crafted instructions that control problem solving by gating the activity retention of, communication between, and learning done by other neural networks. We demonstrate the effectiveness of this approach by showing that it can be applied successfully to solve sequential card matching problems, using both human performance and a top-down symbolic algorithm as experimental controls. Solving this kind of problem makes use of top-down attention control and the binding together of visual features in ways that are easy for symbolic AI systems but not for neural networks to achieve. Our model can not only be instructed on how to solve card matching problems successfully, but its performance also qualitatively (and sometimes quantitatively) matches the performance of both human subjects that we had perform the same task and the top-down symbolic algorithm that we used as an experimental control. We conclude that the core principles underlying the galis framework provide a promising approach to engineering purely neurocomputational systems for problem

  12. Review of high-level waste form properties. [146 bibliographies

    SciTech Connect

    Rusin, J.M.

    1980-12-01

    This report is a review of waste form options for the immobilization of high-level-liquid wastes from the nuclear fuel cycle. This review covers the status of international research and development on waste forms as of May 1979. Although the emphasis in this report is on waste form properties, process parameters are discussed where they may affect final waste form properties. A summary table is provided listing properties of various nuclear waste form options. It is concluded that proposed waste forms have properties falling within a relatively narrow range. In regard to crystalline versus glass waste forms, the conclusion is that either glass of crystalline materials can be shown to have some advantage when a single property is considered; however, at this date no single waste form offers optimum properties over the entire range of characteristics investigated. A long-term effort has been applied to the development of glass and calcine waste forms. Several additional waste forms have enough promise to warrant continued research and development to bring their state of development up to that of glass and calcine. Synthetic minerals, the multibarrier approach with coated particles in a metal matrix, and high pressure-high temperature ceramics offer potential advantages and need further study. Although this report discusses waste form properties, the total waste management system should be considered in the final selection of a waste form option. Canister design, canister materials, overpacks, engineered barriers, and repository characteristics, as well as the waste form, affect the overall performance of a waste management system. These parameters were not considered in this comparison.

  13. High-level waste issues and resolutions document

    SciTech Connect

    Not Available

    1994-05-01

    The High-Level Waste (HLW) Issues and Resolutions Document recognizes US Department of Energy (DOE) complex-wide HLW issues and offers potential corrective actions for resolving these issues. Westinghouse Management and Operations (M&O) Contractors are effectively managing HLW for the Department of Energy at four sites: Idaho National Engineering Laboratory (INEL), Savannah River Site (SRS), West Valley Demonstration Project (WVDP), and Hanford Reservation. Each site is at varying stages of processing HLW into a more manageable form. This HLW Issues and Resolutions Document identifies five primary issues that must be resolved in order to reach the long-term objective of HLW repository disposal. As the current M&O contractor at DOE`s most difficult waste problem sites, Westinghouse recognizes that they have the responsibility to help solve some of the complexes` HLW problems in a cost effective manner by encouraging the M&Os to work together by sharing expertise, eliminating duplicate efforts, and sharing best practices. Pending an action plan, Westinghouse M&Os will take the initiative on those corrective actions identified as the responsibility of an M&O. This document captures issues important to the management of HLW. The proposed resolutions contained within this document set the framework for the M&Os and DOE work cooperatively to develop an action plan to solve some of the major complex-wide problems. Dialogue will continue between the M&Os, DOE, and other regulatory agencies to work jointly toward the goal of storing, treating, and immobilizing HLW for disposal in an environmentally sound, safe, and cost effective manner.

  14. Stability of High-Level Radioactive Waste Forms

    SciTech Connect

    Besmann, T.M.

    2001-06-22

    High-level waste (HLW) glass compositions, processing schemes, limits on waste content, and corrosion/dissolution release models are dependent on an accurate knowledge of melting temperatures and thermochemical values. Unfortunately, existing models for predicting these temperatures are empirically-based, depending on extrapolations of experimental information. In addition, present models of leaching behavior of glass waste forms use simplistic assumptions or experimentally measured values obtained under non-realistic conditions. There is thus a critical need for both more accurate and more widely applicable models for HLW glass behavior, which this project addressed. Significant progress was made in this project on modeling HLW glass. Borosilicate glass was accurately represented along with the additional important components that contain iron, lithium, potassium, magnesium, and calcium. The formation of crystalline inclusions in the glass, an issue in Hanford HLW formulations, was modeled and shown to be predictive. Thus the results of this work have already demonstrated practical benefits with the ability to map compositional regions where crystalline material forms, and therefore avoid that detrimental effect. With regard to a fundamental understanding, added insights on the behavior of the components of glass have been obtained, including the potential formation of molecular clusters. The EMSP project had very significant effects beyond the confines of Environmental Management. The models developed for glass have been used to solve a very costly problem in the corrosion of refractories for glass production. The effort resulted in another laboratory, Sandia National Laboratories-Livermore, to become conversant in the techniques and to apply those through a DOE Office of Industrial Technologies project joint with PPG Industries. The glass industry as a whole is now cognizant of these capabilities, and there is a Glass Manufacturer's Research Institute proposal

  15. PLUTONIUM/HIGH-LEVEL VITRIFIED WASTE BDBE DOSE CALCULATION

    SciTech Connect

    D.C. Richardson

    2003-03-19

    In accordance with the Nuclear Waste Policy Amendments Act of 1987, Yucca Mountain was designated as the site to be investigated as a potential repository for the disposal of high-level radioactive waste. The Yucca Mountain site is an undeveloped area located on the southwestern edge of the Nevada Test Site (NTS), about 100 miles northwest of Las Vegas. The site currently lacks rail service or an existing right-of-way. If the Yucca Mountain site is found suitable for the repository, rail service is desirable to the Office of Civilian Waste Management (OCRWM) Program because of the potential of rail transportation to reduce costs and to reduce the number of shipments relative to highway transportation. A Preliminary Rail Access Study evaluated 13 potential rail spur options. Alternative routes within the major options were also developed. Each of these options was then evaluated for potential land use conflicts and access to regional rail carriers. Three potential routes having few land use conflicts and having access to regional carriers were recommended for further investigation. Figure 1-1 shows these three routes. The Jean route is estimated to be about 120 miles long, the Carlin route to be about 365 miles long, and Caliente route to be about 365 miles long. The remaining ten routes continue to be monitored and should any of the present conflicts change, a re-evaluation of that route will be made. Complete details of the evaluation of the 13 routes can be found in the previous study. The DOE has not identified any preferred route and recognizes that the transportation issues need a full and open treatment under the National Environmental Policy Act. The issue of transportation will be included in public hearings to support development of the Environmental Impact Statement (EIS) proceedings for either the Monitored Retrievable Storage Facility or the Yucca Mountain Project or both.

  16. Radiative Lifetimes for High Levels of Neutral Fe

    NASA Astrophysics Data System (ADS)

    Lawler, James E.; Den Hartog, E.; Guzman, A.

    2013-01-01

    New radiative lifetime measurements for ~ 50 high lying levels of Fe I are reported. Laboratory astrophysics faces a challenge to provide basic spectroscopic data, especially reliable atomic transition probabilities, in the IR region for abundance studies. The availability of HgCdTe (HAWAII) detector arrays has opened IR spectral regions for extensive new spectroscopic studies. The SDSS III APOGEE project in the H-Band is an important example which will penetrate the dust obscuring the Galactic bulge. APOGEE will survey elemental abundances of 100,000 red giant stars in the bulge, bar, disk, and halo of the Milky Way. Many stellar spectra in the H-Band are, as expected, dominated by transitions of Fe I. Most of these IR transitions connect high levels of Fe. Our program has started an effort to meet this challenge with new radiative lifetime measurements on high lying levels of Fe I using time resolved laser induced fluorescence (TRLIF). The TRLIF method is typically accurate to 5% and is efficient. Our goal is to combine these accurate, absolute radiative lifetimes with emission branching fractions [1] to determine log(gf) values of the highest quality for Fe I lines in the UV, visible, and IR. This method was used very successfully by O’Brian et al. [2] on lower levels of Fe I. This method is still the best available for all but very simple spectra for which ab-initio theory is more accurate. Supported by NSF grant AST-0907732. [1] Branching fractions are being measured by M. Ruffoni and J. C. Pickering at Imperial College London. [2] O'Brian, T. R., Wickliffe, M. E., Lawler, J. E., Whaling, W., & Brault, J. W. 1991, J. Opt. Soc. Am. B 8, 1185

  17. High-level disinfection of gastrointestinal endoscope reprocessing.

    PubMed

    Chiu, King-Wah; Lu, Lung-Sheng; Chiou, Shue-Shian

    2015-02-20

    High level disinfection (HLD) of the gastrointestinal (GI) endoscope is not simply a slogan, but rather is a form of experimental monitoring-based medicine. By definition, GI endoscopy is a semicritical medical device. Hence, such medical devices require major quality assurance for disinfection. And because many of these items are temperature sensitive, low-temperature chemical methods, such as liquid chemical germicide, must be used rather than steam sterilization. In summarizing guidelines for infection prevention and control for GI endoscopy, there are three important steps that must be highlighted: manual washing, HLD with automated endoscope reprocessor, and drying. Strict adherence to current guidelines is required because compared to any other medical device, the GI endoscope is associated with more outbreaks linked to inadequate cleaning or disinfecting during HLD. Both experimental evaluation on the surveillance bacterial cultures and in-use clinical results have shown that, the monitoring of the stringent processes to prevent and control infection is an essential component of the broader strategy to ensure the delivery of safe endoscopy services, because endoscope reprocessing is a multistep procedure involving numerous factors that can interfere with its efficacy. Based on our years of experience in the surveillance of culture monitoring of endoscopic reprocessing, we aim in this study to carefully describe what details require attention in the GI endoscopy disinfection and to share our experience so that patients can be provided with high quality and safe medical practices. Quality management encompasses all aspects of pre- and post-procedural care including the efficiency of the endoscopy unit and reprocessing area, as well as the endoscopic procedure itself.

  18. Activity profile of high-level Australian lacrosse players.

    PubMed

    Polley, Chris S; Cormack, Stuart J; Gabbett, Tim J; Polglaze, Ted

    2015-01-01

    Despite lacrosse being one of the fastest growing team sports in the world, there is a paucity of information detailing the activity profile of high-level players. Microtechnology systems (global positioning systems and accelerometers) provide the opportunity to obtain detailed information on the activity profile in lacrosse. Therefore, this study aimed to analyze the activity profile of lacrosse match-play using microtechnology. Activity profile variables assessed relative to minutes of playing time included relative distance (meter per minute), distance spent standing (0-0.1 m·min), walking (0.2-1.7 m·min), jogging (1.8-3.2 m·min), running (3.3-5.6 m·min), sprinting (≥5.7 m·min), number of high, moderate, low accelerations and decelerations, and player load (PL per minute), calculated as the square root of the sum of the squared instantaneous rate of change in acceleration in 3 vectors (medio-lateral, anterior-posterior, and vertical). Activity was recorded from 14 lacrosse players over 4 matches during a national tournament. Players were separated into positions of attack, midfield, or defense. Differences (effect size [ES] ± 90% confidence interval) between positions and periods of play were considered likely positive when there was ≥75% likelihood of the difference exceeding an ES threshold of 0.2. Midfielders had likely covered higher (mean ± SD) meters per minute (100 ± 11) compared with attackers (87 ± 14; ES = 0.89 ± 1.04) and defenders (79 ± 14; ES = 1.54 ± 0.94) and more moderate and high accelerations and decelerations. Almost all variables across positions were reduced in quarter 4 compared with quarter 1. Coaches should accommodate for positional differences when preparing lacrosse players for competition.

  19. Deep borehole disposal of high-level radioactive waste.

    SciTech Connect

    Stein, Joshua S.; Freeze, Geoffrey A.; Brady, Patrick Vane; Swift, Peter N.; Rechard, Robert Paul; Arnold, Bill Walter; Kanney, Joseph F.; Bauer, Stephen J.

    2009-07-01

    Preliminary evaluation of deep borehole disposal of high-level radioactive waste and spent nuclear fuel indicates the potential for excellent long-term safety performance at costs competitive with mined repositories. Significant fluid flow through basement rock is prevented, in part, by low permeabilities, poorly connected transport pathways, and overburden self-sealing. Deep fluids also resist vertical movement because they are density stratified. Thermal hydrologic calculations estimate the thermal pulse from emplaced waste to be small (less than 20 C at 10 meters from the borehole, for less than a few hundred years), and to result in maximum total vertical fluid movement of {approx}100 m. Reducing conditions will sharply limit solubilities of most dose-critical radionuclides at depth, and high ionic strengths of deep fluids will prevent colloidal transport. For the bounding analysis of this report, waste is envisioned to be emplaced as fuel assemblies stacked inside drill casing that are lowered, and emplaced using off-the-shelf oilfield and geothermal drilling techniques, into the lower 1-2 km portion of a vertical borehole {approx}45 cm in diameter and 3-5 km deep, followed by borehole sealing. Deep borehole disposal of radioactive waste in the United States would require modifications to the Nuclear Waste Policy Act and to applicable regulatory standards for long-term performance set by the US Environmental Protection Agency (40 CFR part 191) and US Nuclear Regulatory Commission (10 CFR part 60). The performance analysis described here is based on the assumption that long-term standards for deep borehole disposal would be identical in the key regards to those prescribed for existing repositories (40 CFR part 197 and 10 CFR part 63).

  20. Comparative study of bacteremias caused by Enterococcus spp. with and without high-level resistance to gentamicin. The Grupo Andaluz para el estudio de las Enfermedades Infecciosas.

    PubMed

    Caballero-Granado, F J; Cisneros, J M; Luque, R; Torres-Tortosa, M; Gamboa, F; Díez, F; Villanueva, J L; Pérez-Cano, R; Pasquau, J; Merino, D; Menchero, A; Mora, D; López-Ruz, M A; Vergara, A

    1998-02-01

    A prospective, multicenter study was carried out over a period of 10 months. All patients with clinically significant bacteremia caused by Enterococcus spp. were included. The epidemiological, microbiological, clinical, and prognostic features and the relationship of these features to the presence of high-level resistance to gentamicin (HLRG) were studied. Ninety-three patients with enterococcal bacteremia were included, and 31 of these cases were caused by HLRG (33%). The multivariate analysis selected chronic renal failure, intensive care unit stay, previous use of antimicrobial agents, and Enterococcus faecalis species as the independent risk factors that influenced the development of HLRG. The strains with HLRG showed lower levels of susceptibility to penicillin and ciprofloxacin. Clinical features (except for chronic renal failure) were similar in both groups of patients. HLRG did not influence the prognosis for patients with enterococcal bacteremia in terms of either the crude mortality rate (29% for patients with bacteremia caused by enterococci with HLRG and 28% for patients not infected with strains with HLRG) or the hospital stay after the acquisition of enterococcal bacteremia. Hemodynamic compromise, inappropriate antimicrobial therapy, and mechanical ventilation were revealed in the multivariate analysis to be the independent risk factors for mortality. Prolonged hospitalization was associated with the nosocomial acquisition of bacteremia and polymicrobial infections.

  1. JET MIXING ANALYSIS FOR SRS HIGH-LEVEL WASTE RECOVERY

    SciTech Connect

    Lee, S.

    2011-07-05

    The process of recovering the waste in storage tanks at the Savannah River Site (SRS) typically requires mixing the contents of the tank to ensure uniformity of the discharge stream. Mixing is accomplished with one to four slurry pumps located within the tank liquid. The slurry pump may be fixed in position or they may rotate depending on the specific mixing requirements. The high-level waste in Tank 48 contains insoluble solids in the form of potassium tetraphenyl borate compounds (KTPB), monosodium titanate (MST), and sludge. Tank 48 is equipped with 4 slurry pumps, which are intended to suspend the insoluble solids prior to transfer of the waste to the Fluidized Bed Steam Reformer (FBSR) process. The FBSR process is being designed for a normal feed of 3.05 wt% insoluble solids. A chemical characterization study has shown the insoluble solids concentration is approximately 3.05 wt% when well-mixed. The project is requesting a Computational Fluid Dynamics (CFD) mixing study from SRNL to determine the solids behavior with 2, 3, and 4 slurry pumps in operation and an estimate of the insoluble solids concentration at the suction of the transfer pump to the FBSR process. The impact of cooling coils is not considered in the current work. The work consists of two principal objectives by taking a CFD approach: (1) To estimate insoluble solids concentration transferred from Tank 48 to the Waste Feed Tank in the FBSR process and (2) To assess the impact of different combinations of four slurry pumps on insoluble solids suspension and mixing in Tank 48. For this work, several different combinations of a maximum of four pumps are considered to determine the resulting flow patterns and local flow velocities which are thought to be associated with sludge particle mixing. Two different elevations of pump nozzles are used for an assessment of the flow patterns on the tank mixing. Pump design and operating parameters used for the analysis are summarized in Table 1. The baseline

  2. Correlation between Infective Factors and Antibiotic Resistance in Enterococci Clinical Isolates in West of Iran

    PubMed Central

    Nasaj, Mona; Mousavi, Seyed Masoud

    2017-01-01

    The present study was done to scrutinize the possible relation between infective genes and antimicrobial resistance in Enterococcus faecalis and Enterococcus faecium. Considering the fact that the presence of recognized infective determinants among clinical isolates may promote the emergence of infections and persistence of Enterococci in hospital settings, which can lead to an increase in antimicrobial resistance. 175 E. faecalis and 67 E. faecium isolated from clinical specimens were used. The isolates were identified, and then antibiotic susceptibility testing was performed. The MIC of vancomycin and teicoplanin were determined by broth microdilution method. The presence of infective genes esp, hyl and asa1 was scrutinized using PCR. Of the 280 enterococcal isolates, 175 (62.5%) isolates were identified as E. faecalis, 67 (24%) as E. faecium and 38 (13.5%) as Enterococcus spp. The results of the antibiotic susceptibility testing showed resistance rates of 5% and 73% to vancomycin and teicoplanin in E. faecalis and E. faecium isolates, respectively. The statistical analysis showed that the esp infective gene has significant associations with ciprofloxacin, erythromycin and tetracycline in E. faecium and with chloramphenicol in E. faecalis strains; the hyl with teicoplanin and vancomycin in E. faecium strains; and also asa1 with vancomycin in E. faecium and with ampicillin and chloramphenicol in E. faecalis strains. Regarding the relationships between virulence genes and antibiotic resistance in strains of E. faecalis and E. faecium, detection of infective factors associated with invasive diseases has become a major issue of concern. PMID:28184339

  3. Infrequent occurrence of vancomycin-resistant enterococci in poultry from Malaysian wet markets.

    PubMed

    Ong, C H S; Asaad, M; Lim, K C; Ngeow, Y F

    2002-12-01

    Fifty samples of chicken, duck and geese faeces were obtained from 13 wet markets in Kuala Lumpur to study the prevalence of vancomycin-resistant enterococci (VRE) among local market poultry. Biotyping of colonies grown on azide agar incubated at 45 degrees C yielded E. pseudoavium, E. faecalis, E. faecium and E. gallinarum from chicken faeces and E. malodoratus, E. faecalis, E. faecium, E. gallinarum, E. hirae/dispar, and E. durans from goose and duck faeces. On agar containing 6 mg/ l of vancomycin, one strain of E. flavescens was identified, giving a VRE detection rate of 2.0%. This isolate had a vancomycin M.I.C. of 8 mg/l as determined by the Etest, and the van C-3 gene that was identified by PCR followed by sequence analysis. The prevalence of VRE among poultry sold in local markets appears to be low, and may reflect the infrequent use of antimicrobials in our poultry farms. Nevertheless, the possibility of human acquisition of microbes via the food chain cautions against the use of antimicrobials in animal husbandry that may encourage the emergence and spread of multi-drug resistant organisms like the VRE among animal microbial flora.

  4. Molecular Analysis of Vancomycin-Resistant Enterococci Isolated from Regional Hospitals in Trinidad and Tobago

    PubMed Central

    Akpaka, Patrick E.; Kissoon, Shivnarine; Jayaratne, Padman

    2016-01-01

    Geographic spread of vancomycin-resistant enterococci (VRE) clones in cities, countries, or even continents has been identified by molecular techniques. This study aimed at characterizing virulent genes and determining genetic relatedness of 45 VRE isolates from Trinidad and Tobago using molecular tools, including polymerase chain reaction, pulsed-field gel electrophoresis (PFGE), and Random Amplification Polymorphic DNA (RAPD). The majority (84%) of the isolates were Enterococcus faecium possessing vanA gene while the rest (16%) were Enterococcus faecalis possessing vanB. The esp gene was found in all 45 VRE isolates while hyl genes were found only in E. faecium species. The E. faecium species expressed five distinct PFGE patterns. The predominant clones with similar or common patterns belonged to clones one and three, and each had 11 (29%) of the VRE isolates. Plasmid content was identified in representative isolates from each clonal group. By contrast, the E. faecalis species had one PFGE pattern suggesting the presence of an occult and limited clonal spread. The emergence of VRE in the country seems to be related to intra/interhospital dissemination of an epidemic clone carrying the vanA element. Therefore, infection control measures will be warranted to prevent any potential outbreak and spread of VRE in the country. PMID:27299153

  5. Temporal trends and risk factors for healthcare-associated vancomycin-resistant enterococci in adults

    PubMed Central

    Monteserin, N.; Larson, E.

    2016-01-01

    SUMMARY Background Published data regarding temporal trends in vancomycin-resistant enterococci (VRE) prevalence within specific regions or healthcare systems are scarce. Aim To characterize temporal trends and risk factors for healthcare-associated infections caused by VRE. Methods The study included all adult discharges occurring from 2006 to 2014 with an enterococcal infection from three hospitals in a large academic healthcare system. Bivariate analyses were used to identify statistically significant factors associated with vancomycin-susceptible or -resistant infection. Statistically significant variables were included in a final logistic regression model. Trends assessed whether the proportion of enterococcal infections resistant to vancomycin changed over time. Findings The sample included 10,186 adults with first-time healthcare-associated enterococcal infection. Significant risk factors (P ≤ 0.05) for VRE in the final logistic regression model included: tertiary 1 hospital, intensive care unit length of stay, higher Charlson Comorbidity Index, previous immunosuppressive or chemotherapeutic medications, previous hospitalization, renal failure, malignancy, longer length of stay prior to infection, taking an antibiotic prior to infection, being female, and having an infection in winter or spring. Between 2006 and 2014, the rate of resistance varied from 37.1 to 42.9% but there were no significant differences in the proportion resistant to vancomycin over time (P = 0.36). Conclusion Research targeted at risk factors is important to decrease the amount of VRE infections. PMID:27645212

  6. Utility of a focused vancomycin-resistant enterococci screening protocol to identify colonization in hospitalized children.

    PubMed

    Weddle, Gina; Jackson, Mary Anne; Selvarangan, Rangaraj

    2012-11-01

    Screening for vancomycin-resistant enterococci (VRE) is controversial, and disagreement exists on policy implementation. This study investigated the likelihood of a positive test using 1, 2, or 3 rectal screenings for VRE colonization. In this descriptive study of positive VRE screening cultures, a total of 1211 VRE screens identified 41 positive results. The mean age of these positive patients was 5.7 years. Thirty-nine of the 41 had a chronic illness, and only 2 were healthy. Diagnoses included pulmonary disease in 11 patients and chronic gastrointestinal abnormality in 7. Six patients had been born preterm, and 12 had been treated in a neonatal intensive care unit within the previous 6 months. Thirty-six of the 41 positive results were identified on the first screen. The likelihood of subsequently having a positive screen after a negative screen was 0.43% (95% confidence interval, 0.15%-1.02%). The cost of cultures plus isolation was $50,000 for the study period. Our data show that the likelihood of detecting a positive VRE culture after an initial negative was low, particularly in otherwise healthy children.

  7. Transport of enterococci and F+ coliphage through the saturated zone of the beach aquifer.

    PubMed

    de Sieyes, Nicholas R; Russell, Todd L; Brown, Kendra I; Mohanty, Sanjay K; Boehm, Alexandria B

    2016-02-01

    Coastal groundwater has been implicated as a source of microbial pollution to recreational beaches. However, there is little work investigating the transport of fecal microbes through beach aquifers where waters of variable salinity are present. In this study, the potential for fecal indicator organisms enterococci (ENT) and F+ coliphage to be transported through marine beach aquifers was investigated. Native sediment and groundwaters were collected from the fresh and saline sections of the subterranean estuary at three beaches along the California coast where coastal communities utilize septic systems for wastewater treatment. Groundwaters were seeded with sewage and removal of F+ coliphage and ENT by the sediments during saturated flow was tested in laboratory column experiments. Removal varied significantly between beach and organism. F+ coliphage was removed to a greater extent than ENT, and removal was greater in saline sediments and groundwater than fresh. At one of the three beaches, a field experiment was conducted to investigate the attenuation of F+ coliphage and ENT down gradient of a septic leach field. ENT were detected up to 24 m from the leach field. The column study and field observations together suggest ENT can be mobile within native aquifer sediments and groundwater under certain conditions.

  8. Vancomycin-resistant enterococci from nosocomial, community, and animal sources in the United States.

    PubMed Central

    Coque, T M; Tomayko, J F; Ricke, S C; Okhyusen, P C; Murray, B E

    1996-01-01

    The presence of vancomycin-resistant enterococci (VRE) was looked for in fecal samples from 104 healthy volunteers (3 with hospital exposure), 100 selected hospitalized patients, and various environmental sources (44 commercial chickens, 5 farm-raised chickens, 3 turkeys, and 2 chicken farm lagoon slurries). Five probiotic preparations were also studied. No VRE with vanA or vanB genes were isolated from the healthy volunteers without hospital exposure, environmental sources, or probiotic preparations. VRE with vanB were found in the stools of 16% of the high-risk hospitalized patients and in one volunteer with hospital contact. All VRE examined could be classified into one of two clones by pulsed-field gel electrophoresis. VRE from 11 of the colonized patients were quantified and ranged from 10(3) to 10(6) CFU/g of stool. This study, in contrast to findings in Europe, failed to find evidence of VanA- or VanB-type VRE in the community or environmental sources in Houston, Texas, and suggests that these settings are not a likely source of VRE in hospitals in this geographic area. PMID:8913473

  9. A survey of the enterococci isolated from an artisanal Italian goat's cheese (semicotto caprino).

    PubMed

    Suzzi, G; Caruso, M; Gardini, F; Lombardi, A; Vannini, L; Guerzoni, M E; Andrighetto, C; Lanorte, M T

    2000-08-01

    Enterococci were isolated from semicotto caprino cheese, a traditional cheese produced in Southern Italy: they were a significant part of the microbial population of this cheese, confirming the importance of the presence of these micro-organisms during cheese-making and ripening. They were also identified and studied for their phenotypic and genotypic characteristics: Enterococcus faecalis and Ent. faecium were the most frequently isolated species, followed by Ent. durans, Ent. hirae and Ent. gallinarum. None of the isolates showed lipolytic activity, whereas they were characterized by a relevant proteolytic activity as well as an antagonistic activity towards Listeria innocua. One strain of Ent. gallinarum showed a low-level resistance to vancomycin, while six out of the 79 Ent. faecalis strains possessed beta-haemolysis reaction. The highest acidifying potential in skim milk was obtained by Ent. faecalis isolates. Thirty enterococcal strains representative of the different species at different ripening times were analysed by means of RAPD-PCR, and revealed species-specific profiles for all the considered species.

  10. Cementitious Grout for Closing SRS High Level Waste Tanks - 12315

    SciTech Connect

    Langton, C.A.; Stefanko, D.B.; Burns, H.H.; Waymer, J.; Mhyre, W.B.; Herbert, J.E.; Jolly, J.C. Jr.

    2012-07-01

    In 1997, the first two United States Department of Energy (US DOE) high level waste tanks (Tanks 17-F and 20-F: Type IV, single shell tanks) were taken out of service (permanently closed) at the Savannah River Site (SRS). In 2012, the DOE plans to remove from service two additional Savannah River Site (SRS) Type IV high-level waste tanks, Tanks 18-F and 19-F. These tanks were constructed in the late 1950's and received low-heat waste and do not contain cooling coils. Operational closure of Tanks 18-F and 19-F is intended to be consistent with the applicable requirements of the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and will be performed in accordance with South Carolina Department of Health and Environmental Control (SCDHEC). The closure will physically stabilize two 4.92E+04 cubic meter (1.3 E+06 gallon) carbon steel tanks and isolate and stabilize any residual contaminants left in the tanks. Ancillary equipment abandoned in the tanks will also be filled to the extent practical. A Performance Assessment (PA) has been developed to assess the long-term fate and transport of residual contamination in the environment resulting from the operational closure of the F-Area Tank Farm (FTF) waste tanks. Next generation flowable, zero-bleed cementitious grouts were designed, tested, and specified for closing Tanks 18-F and 19-F and for filling the abandoned equipment. Fill requirements were developed for both the tank and equipment grouts. All grout formulations were required to be alkaline with a pH of 12.4 and to be chemically reducing with a reduction potential (Eh) of -200 to -400. Grouts with this chemistry stabilize potential contaminants of concern. This was achieved by including Portland cement and Grade 100 slag in the mixes, respectively. Ingredients and proportions of cementitious reagents were selected and adjusted to support the mass placement strategy developed by

  11. Frequency of VanA, VanB and VanH variants amongst vancomycin-resistant enterococci isolated from patients in central region of Iran

    PubMed Central

    Rezvani, Jaafar; Nasr, Reza; T. Shamsabadi, Fatemeh; Akbari Eidgahi, Mohammad Reza

    2016-01-01

    Aim: The aim of this study was to investigate the VRE frequency and the rate of each gene in isolated enterococci from patients with intestinal infection in the central region of Iran. Background: Enterococci infections are a public health growing concern due to the glycopeptide antibiotics resistance especially vancomycin. Genes, vanA, B, and H contribute to the influence of vancomycin-resistant enterococci (VRE). Patients and methods: This study was conducted from January to July 2014 in Shahrood university hospital. Enterococci isolation and its antibacterial susceptibility were performed by culturing in Aesculin Azide agar and Kirby-Bauer method, respectively. Vancomycin-resistant genes were screened through conventional PCR, and subsequently sequenced. Results: Among 265 specimens, 100 isolates revealed enterococci, in which E. faecalis (91%) and E. faecium (9%). The isolated enterococci were resistant to vancomycin (6%) and chloramphenicol (21%), whereas their large proportions (94% to 100%) were multi-drug resistant. All VRE isolates belonged to E. faecalis, conversely, the E. faecium were susceptible to the same antibiotic. Both vanA and vanH genes were identified in all VRE isolates, although, no vanB gene was indicated. Homology analysis of sequenced amplicons verified the full length compatibility to the worldwide reported genes. Conclusion: The present study revealed VR E. faecalis in gastroenteritis patients and resistance factor for vanA and vanH genes are coordinated. Since enterococci isolates were all multidrug resistance, increase in VR E. faecalis vanA / vanH in this area could be expected. PMID:27895857

  12. Advanced High-Level Waste Glass Research and Development Plan

    SciTech Connect

    Peeler, David K.; Vienna, John D.; Schweiger, Michael J.; Fox, Kevin M.

    2015-07-01

    The U.S. Department of Energy Office of River Protection (ORP) has implemented an integrated program to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product quality requirements. The integrated ORP program is focused on providing a technical, science-based foundation from which key decisions can be made regarding the successful operation of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) facilities. The fundamental data stemming from this program will support development of advanced glass formulations, key process control models, and tactical processing strategies to ensure safe and successful operations for both the low-activity waste (LAW) and high-level waste (HLW) vitrification facilities with an appreciation toward reducing overall mission life. The purpose of this advanced HLW glass research and development plan is to identify the near-, mid-, and longer-term research and development activities required to develop and validate advanced HLW glasses and their associated models to support facility operations at WTP, including both direct feed and full pretreatment flowsheets. This plan also integrates technical support of facility operations and waste qualification activities to show the interdependence of these activities with the advanced waste glass (AWG) program to support the full WTP mission. Figure ES-1 shows these key ORP programmatic activities and their interfaces with both WTP facility operations and qualification needs. The plan is a living document that will be updated to reflect key advancements and mission strategy changes. The research outlined here is motivated by the potential for substantial economic benefits (e.g., significant increases in waste throughput and reductions in glass volumes) that will be realized when advancements in glass formulation continue and models supporting facility operations are implemented. Developing and applying advanced

  13. Development of Crystal-Tolerant High-Level Waste Glasses

    SciTech Connect

    Matyas, Josef; Vienna, John D.; Schaible, Micah J.; Rodriguez, Carmen P.; Crum, Jarrod V.; Arrigoni, Alyssa L.; Tate, Rachel M.

    2010-12-17

    Twenty five glasses were formulated. They were batched from HLW AZ-101 simulant or raw chemicals and melted and tested with a series of tests to elucidate the effect of spinel-forming components (Ni, Fe, Cr, Mn, and Zn), Al, and noble metals (Rh2O3 and RuO2) on the accumulation rate of spinel crystals in the glass discharge riser of the high-level waste (HLW) melter. In addition, the processing properties of glasses, such as the viscosity and TL, were measured as a function of temperature and composition. Furthermore, the settling of spinel crystals in transparent low-viscosity fluids was studied at room temperature to access the shape factor and hindered settling coefficient of spinel crystals in the Stokes equation. The experimental results suggest that Ni is the most troublesome component of all the studied spinel-forming components producing settling layers of up to 10.5 mm in just 20 days in Ni-rich glasses if noble metals or a higher concentration of Fe was not introduced in the glass. The layer of this thickness can potentially plug the bottom of the riser, preventing glass from being discharged from the melter. The noble metals, Fe, and Al were the components that significantly slowed down or stopped the accumulation of spinel at the bottom. Particles of Rh2O3 and RuO2, hematite and nepheline, acted as nucleation sites significantly increasing the number of crystals and therefore decreasing the average crystal size. The settling rate of ≤10-μm crystal size around the settling velocity of crystals was too low to produce thick layers. The experimental data for the thickness of settled layers in the glasses prepared from AZ-101 simulant were used to build a linear empirical model that can predict crystal accumulation in the riser of the melter as a function of concentration of spinel-forming components in glass. The developed model predicts the thicknesses of accumulated layers quite well, R2 = 0.985, and can be become an efficient tool for the formulation

  14. Corrosion issues in high-level nuclear waste containers

    NASA Astrophysics Data System (ADS)

    Asl, Samin Sharifi

    In this dissertation different aspects of corrosion and electrochemistry of copper, candidate canister material in Scandinavian high-level nuclear waste disposal program, including the thermodynamics and kinetics of the reactions that are predicted to occur in the practical system have been studied. A comprehensive thermodynamic study of copper in contact with granitic groundwater of the type and composition that is expected in the Forsmark repository in Sweden has been performed. Our primary objective was to ascertain whether copper would exist in the thermodynamically immune state in the repository, in which case corrosion could not occur and the issue of corrosion in the assessment of the storage technology would be moot. In spite of the fact that metallic copper has been found to exist for geological times in granitic geological formations, copper is well-known to be activated from the immune state to corrode by specific species that may exist in the environment. The principal activator of copper is known to be sulfur in its various forms, including sulfide (H2S, HS-, S2-), polysulfide (H2Sx, HSx -, Sx 2-), poly sulfur thiosulfate ( SxO3 2-), and polythionates (SxO6 2-). A comprehensive study of this aspect of copper chemistry has never been reported, and yet an understanding of this issue is vital for assessing whether copper is a suitable material for fabricating canisters for the disposal of HLNW. Our study identifies and explores those species that activate copper; these species include sulfur-containing entities as well as other, non-sulfur species that may be present in the repository. The effects of temperature, solution pH, and hydrogen pressure on the kinetics of the hydrogen electrode reaction (HER) on copper in borate buffer solution have been studied by means of steady-state polarization measurements, including electrochemical impedance spectroscopy (EIS). In order to obtain electrokinetic parameters, such as the exchange current density and the

  15. Occurrence of antibiotic resistance genes and mobile genetic elements in enterococci and genomic DNA during anaerobic digestion of pharmaceutical waste sludge with different pretreatments.

    PubMed

    Tong, Juan; Lu, XueTing; Zhang, JunYa; Sui, Qianwen; Wang, Rui; Chen, Meixue; Wei, Yuansong

    2017-03-22

    Pharmaceutical waste sludge harbors large amounts of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs), and it is necessary to study the reduction of ARGs and MGEs during sludge treatment. Therefore, the antibiotic resistance phenotypes and genotypes of enterococci, and the ARGs and MGEs in genomic DNA were investigated during anaerobic digestion (AD) with microwave (MW), thermal hydrolysis (TH) and ozone pretreatment. Results showed that sludge pretreatment increased the occurrence of the resistance phenotypes and genotypes of enterococci. During AD, the resistance of enterococci to macrolides decreased, except for in the MW-pretreated sludge. Horizontal gene transfer and co-occurrence of ermB and tetM in enterococci resulted in increased tetracycline resistance of enterococci throughout the sludge treatment. MGEs such as intI1, ISCR1 and Tn916/1545 had a significant effect on the distribution of ARGs. AD with pretreatment, especially TH pretreatment, resulted in greater ARGs and MGEs reduction and improved methane production.

  16. Development of predictive models for determining enterococci levels at Gulf Coast beaches.

    PubMed

    Zhang, Zaihong; Deng, Zhiqiang; Rusch, Kelly A

    2012-02-01

    The US EPA BEACH Act requires beach managers to issue swimming advisories when water quality standards are exceeded. While a number of methods/models have been proposed to meet the BEACH Act requirement, no systematic comparisons of different methods against the same data series are available in terms of relative performance of existing methods. This study presents and compares three models for nowcasting and forecasting enterococci levels at Gulf Coast beaches in Louisiana, USA. One was developed using the artificial neural network (ANN) in MATLAB Toolbox and the other two were based on the US EPA Virtual Beach (VB) Program. A total of 944 sets of environmental and bacteriological data were utilized. The data were collected and analyzed weekly during the swimming season (May-October) at six sites of the Holly Beach by Louisiana Beach Monitoring Program in the six year period of May 2005-October 2010. The ANN model includes 15 readily available environmental variables such as salinity, water temperature, wind speed and direction, tide level and type, weather type, and various combinations of antecedent rainfalls. The ANN model was trained, validated, and tested using 308, 103, and 103 data sets (collected in 2007, 2008, and 2009) with an average linear correlation coefficient (LCC) of 0.857 and a Root Mean Square Error (RMSE) of 0.336. The two VB models, including a linear transformation-based model and a nonlinear transformation-based model, were constructed using the same data sets. The linear VB model with 6 input variables achieved an LCC of 0.230 and an RMSE of 1.302 while the nonlinear VB model with 5 input variables produced an LCC of 0.337 and an RMSE of 1.205. In order to assess the predictive performance of the ANN and VB models, hindcasting was conducted using a total of 430 sets of independent environmental and bacteriological data collected at six Holly Beach sites in 2005, 2006, and 2010. The hindcasting results show that the ANN model is capable of

  17. Biochemical Characterization of Cardiolipin Synthase Mutations Associated with Daptomycin Resistance in Enterococci

    PubMed Central

    Davlieva, Milya; Zhang, Wanna; Arias, Cesar A.

    2013-01-01

    Daptomycin (DAP) resistance in enterococci has been linked to mutations in genes that alter the cell envelope stress response (CESR) (liaFSR) and changes in enzymes that directly affect phospholipid homeostasis, and these changes may alter membrane composition, such as that of cardiolipin synthase (Cls). While Cls substitutions are observed in response to DAP therapy, the effect of these mutations on Cls activity remains obscure. We have expressed, purified, and characterized Cls enzymes from both Enterococcus faecium S447 (residues 52 to 482; Cls447a) and Enterococcus faecalis S613 (residues 53 to 483; Cls613a) as well as Cls variants harboring a single-amino-acid change derived from DAP-resistant isolates of E. faecium. E. faecium Cls447a and E. faecalis Cls613a are tightly associated with the membrane and copurify with their substrate, phosphatidylglycerol (PG), and product, cardiolipin (CL). The amount of PG that copurifies with Cls is in molar excess to protein, suggesting that the enzyme localizes to PG-rich membrane regions. Both Cls447aH215R and Cls447aR218Q showed an increase in Vmax (μM CL/min/μM protein) from 0.16 ± 0.01 to 0.26 ± 0.02 and 0.26 ± 0.04, respectively, indicating that mutations associated with adaptation to DAP increase Cls activity. Modeling of Cls447a to Streptomyces sp. phospholipase D indicates that the adaptive mutations Cls447aH215R and Cls447aR218Q are proximal to the phospholipase domain 1 (PLD1) active site and near the putative nucleophile H217. As mutations to Cls are part of a larger genomic adaptation process, increased Cls activity is likely to be highly epistatic with other changes to facilitate DAP resistance. PMID:23114777

  18. Synergy of Penicillin-Netilmicin Combinations Against Enterococci Including Strains Highly Resistant to Streptomycin or Kanamycin

    PubMed Central

    Sanders, Christine C.

    1977-01-01

    The in vitro activity of combinations of penicillin and netilimicin was determined against 20 clinical isolates of enterococci and compared with that obtained in simultaneous tests with penicillin/sisomicin, penicillin/streptomycin, and penicillin/kanamycin. Synergy between the two drugs in each combination was determined by the use of quantitative kill curves and was defined as a killing by the combination at least 100-fold greater than that produced by the most effective drug alone. Penicillin/netilmicin and penicillin/sisomicin combinations were found to be synergistic against the majority of isolates tested, including strains resistant to penicillin/streptomycin or penicillin/kanamycin combinations. This synergy with penicillin could be demonstrated at a concentration of ≤7 μg/ml for either netilmicin or sisomicin. Studies on the kinetics of killing produced by these combinations showed the rate and extent of killing to be directly dependent upon the organism's relative susceptibility to the aminoglycoside alone and the aminoglycoside concentration in the combination. Results also indicated that the interaction between penicillin and netilmicin was true synergy; i.e., rapid and complete killing was produced by combinations containing each drug at concentrations insufficient to produce any killing alone, and the killing observed could not be produced by either drug alone at a concentration equivalent to the total drug concentration in the combination. The potential clinical application of this synergistic interaction should be investigated further, especially in view of recent reports showing netilmicin to be considerably less toxic than gentamicin in experimental animals. PMID:242509

  19. Molecular Diversity and Evolutionary Relationships of Tn1546-Like Elements in Enterococci from Humans and Animals

    PubMed Central

    Willems, Rob J. L.; Top, Janetta; van den Braak, Nicole; van Belkum, Alex; Mevius, Dik J.; Hendriks, Giel; van Santen-Verheuvel, Marga; van Embden, Jan D. A.

    1999-01-01

    We report on a detailed study on the molecular diversity and evolutionary relationships of Tn1546-like elements in vancomycin-resistant enterococci (VRE) from humans and animals. Restriction fragment length polymorphism (RFLP) analysis of the VanA transposon of 97 VRE revealed seven different Tn1546 types. Subsequent sequencing of the complete VanA transposons of 13 VRE isolates representing the seven RFLP types followed by sequencing of the identified polymorphic regions in 84 other VanA transposons resulted in the identification of 22 different Tn1546 derivatives. Differences between the Tn1546 types included point mutations in orf1, vanS, vanA, vanX, and vanY. Moreover, insertions of an IS1216V-IS3-like element in orf1, of IS1251 in the vanS-vanH intergenic region, and of IS1216V in the vanX-vanY intergenic region were found. The presence of insertion sequence elements was often associated with deletions in Tn1546. Identical Tn1546 types were found among isolates from humans and farm animals in The Netherlands, suggesting the sharing of a common vancomycin resistance gene pool. Application of the genetic analysis of Tn1546 to VRE isolates causing infections in hospitals in Oxford, United Kingdom, and Chicago, Ill., suggested the possibility of the horizontal transmission of the vancomycin resistance transposon. The genetic diversity in Tn1546 combined with epidemiological data suggest that the DNA polymorphism among Tn1546 variants can successfully be exploited for the tracing of the routes of transmission of vancomycin resistance genes. PMID:10049255

  20. Intra-abdominal Infections: The Role of Anaerobes, Enterococci, Fungi, and Multidrug-Resistant Organisms

    PubMed Central

    Marcus, Gil; Levy, Samuel; Salhab, Ghaleb; Mengesha, Bethlehem; Tzuman, Oran; Shur, Shira; Burke, Erica; Mayeda, Rebecca Cruz; Cochavi, Lior; Perluk, Idan; Zaidenstein, Ronit; Lazarovitch, Tsilia; Dadon, Mor

    2016-01-01

    Background. Intra-abdominal infections (IAI) constitute a common reason for hospitalization. However, there is lack of standardization in empiric management of (1) anaerobes, (2) enterococci, (3) fungi, and (4) multidrug-resistant organisms (MDRO). The recommendation is to institute empiric coverage for some of these organisms in “high-risk community-acquired” or in “healthcare-associated” infections (HCAI), but exact definitions are not provided. Methods. Epidemiological study of IAI was conducted at Assaf Harofeh Medical Center (May–November 2013). Logistic and Cox regressions were used to analyze predictors and outcomes of IAI, respectively. The performances of established HCAI definitions to predict MDRO-IAI upon admission were calculated by receiver operating characteristic (ROC) curve analyses. Results. After reviewing 8219 discharge notes, 253 consecutive patients were enrolled (43 [17%] children). There were 116 patients with appendicitis, 93 biliary infections, and 17 with diverticulitis. Cultures were obtained from 88 patients (35%), and 44 of them (50%) yielded a microbiologically confirmed IAI: 9% fungal, 11% enterococcal, 25% anaerobic, and 34% MDRO. Eighty percent of MDRO-IAIs were present upon admission, but the area under the ROC curve of predicting MDRO-IAI upon admission by the commonly used HCAI definitions were low (0.73 and 0.69). Independent predictors for MDRO-IAI were advanced age and active malignancy. Conclusions. Multidrug-resistant organism-IAIs are common, and empiric broad-spectrum coverage is important among elderly patients with active malignancy, even if the infection onset was outside the hospital setting, regardless of current HCAI definitions. Outcomes analyses suggest that empiric regimens should routinely contain antianaerobes (except for biliary IAI); however, empiric antienterococcal or antifungals regimens are seldom needed. PMID:28018930

  1. Global Emergence and Dissemination of Enterococci as Nosocomial Pathogens: Attack of the Clones?

    PubMed Central

    Guzman Prieto, Ana M.; van Schaik, Willem; Rogers, Malbert R. C.; Coque, Teresa M.; Baquero, Fernando; Corander, Jukka; Willems, Rob J. L.

    2016-01-01

    Enterococci are Gram-positive bacteria that are found in plants, soil and as commensals of the gastrointestinal tract of humans, mammals, and insects. Despite their commensal nature, they have also become globally important nosocomial pathogens. Within the genus Enterococcus, Enterococcus faecium, and Enterococcus faecalis are clinically most relevant. In this review, we will discuss how E. faecium and E. faecalis have evolved to become a globally disseminated nosocomial pathogen. E. faecium has a defined sub-population that is associated with hospitalized patients and is rarely encountered in community settings. These hospital-associated clones are characterized by the acquisition of adaptive genetic elements, including genes involved in metabolism, biofilm formation, and antibiotic resistance. In contrast to E. faecium, clones of E. faecalis isolated from hospitalized patients, including strains causing clinical infections, are not exclusively found in hospitals but are also present in healthy individuals and animals. This observation suggests that the division between commensals and hospital-adapted lineages is less clear for E. faecalis than for E. faecium. In addition, genes that are reported to be associated with virulence of E. faecalis are often not unique to clinical isolates, but are also found in strains that originate from commensal niches. As a reflection of more ancient association of E. faecalis with different hosts, these determinants Thus, they may not represent genuine virulence genes but may act as host-adaptive functions that are useful in a variety of intestinal environments. The scope of the review is to summarize recent trends in the emergence of antibiotic resistance and explore recent developments in the molecular epidemiology, population structure and mechanisms of adaptation of E. faecium and E. faecalis. PMID:27303380

  2. Global Emergence and Dissemination of Enterococci as Nosocomial Pathogens: Attack of the Clones?

    PubMed

    Guzman Prieto, Ana M; van Schaik, Willem; Rogers, Malbert R C; Coque, Teresa M; Baquero, Fernando; Corander, Jukka; Willems, Rob J L

    2016-01-01

    Enterococci are Gram-positive bacteria that are found in plants, soil and as commensals of the gastrointestinal tract of humans, mammals, and insects. Despite their commensal nature, they have also become globally important nosocomial pathogens. Within the genus Enterococcus, Enterococcus faecium, and Enterococcus faecalis are clinically most relevant. In this review, we will discuss how E. faecium and E. faecalis have evolved to become a globally disseminated nosocomial pathogen. E. faecium has a defined sub-population that is associated with hospitalized patients and is rarely encountered in community settings. These hospital-associated clones are characterized by the acquisition of adaptive genetic elements, including genes involved in metabolism, biofilm formation, and antibiotic resistance. In contrast to E. faecium, clones of E. faecalis isolated from hospitalized patients, including strains causing clinical infections, are not exclusively found in hospitals but are also present in healthy individuals and animals. This observation suggests that the division between commensals and hospital-adapted lineages is less clear for E. faecalis than for E. faecium. In addition, genes that are reported to be associated with virulence of E. faecalis are often not unique to clinical isolates, but are also found in strains that originate from commensal niches. As a reflection of more ancient association of E. faecalis with different hosts, these determinants Thus, they may not represent genuine virulence genes but may act as host-adaptive functions that are useful in a variety of intestinal environments. The scope of the review is to summarize recent trends in the emergence of antibiotic resistance and explore recent developments in the molecular epidemiology, population structure and mechanisms of adaptation of E. faecium and E. faecalis.

  3. Heterogeneity of macrolide-lincosamide-streptogramin B resistance phenotypes in enterococci.

    PubMed

    Min, Yu-Hong; Jeong, Jae-Hee; Choi, Yun-Jeong; Yun, Hee-Jeong; Lee, Kyungwon; Shim, Mi-Ja; Kwak, Jin-Hwan; Choi, Eung-Chil

    2003-11-01

    We determined the macrolide resistance phenotypes of 241 clinical isolates of erythromycin-resistant enterococci (MICs, > or = 1 microg/ml), including 147 Enterococcus faecalis strains and 94 Enterococcus faecium strains, collected from a hospital in Seoul, Korea, between 1999 and 2000. By the erythromycin (40 micro g)-josamycin (100 microg) double-disk test, 93 strains were assigned to the constitutive macrolide, lincosamide, and streptogramin B (MLS(B)) resistance (cMLS(B)) phenotype, and the remaining 148 strains were assigned to the inducible MLS(B) resistance (iMLS(B)) phenotype. Of the strains with the iMLS(B) phenotype, 36 exhibited a reversibly inducible MLS(B) (riMLS(B)) phenotype, i.e., blunting of the erythromycin zone of inhibition, which indicates that the 16-membered-ring macrolide josamycin is a more effective inducer than the 14-membered-ring macrolide erythromycin. Sequence analysis of the regulatory regions of the erm(B) genes from all of the strains exhibiting the riMLS(B) phenotype revealed not only erm(Bv) [where v represents variant; previously erm(AMR)] (n = 13), as reported previously, but also three kinds of erm(B) variants, which were designated erm(Bv1) (n = 17), erm(Bv2) (n = 3), and erm(Bv3) (n = 3), respectively. In lacZ reporter gene assays of these variants, the 16-membered-ring macrolide tylosin had stronger inducibility than erythromycin at > or = 0.1 microg/ml. These findings highlight the versatility of erm(B) in induction specificity.

  4. Cost evaluation of a DSN high level real-time language

    NASA Technical Reports Server (NTRS)

    Mckenzie, M.

    1977-01-01

    The hypothesis that the implementation of a DSN High Level Real Time Language will reduce real time software expenditures is explored. The High Level Real Time Language is found to be both affordable and cost-effective.

  5. High-level waste program progress report, April 1, 1980-June 30, 1980

    SciTech Connect

    1980-08-01

    The highlights of this report are on: waste management analysis for nuclear fuel cycles; fixation of waste in concrete; study of ceramic and cermet waste forms; alternative high-level waste forms development; and high-level waste container development.

  6. Multiple-Antibiotic Resistance of Enterococcus spp. Isolated from Commercial Poultry Production Environments

    PubMed Central

    Hayes, Joshua R.; English, Linda L.; Carr, Lewis E.; Wagner, David D.; Joseph, Sam W.

    2004-01-01

    The potential impact of food animals in the production environment on the bacterial population as a result of antimicrobial drug use for growth enhancement continues to be a cause for concern. Enterococci from 82 farms within a poultry production region on the eastern seaboard were isolated to establish a baseline of susceptibility profiles for a number of antimicrobials used in production as well as clinical environments. Of the 541 isolates recovered, Enterococcus faecalis (53%) and E. faecium (31%) were the predominant species, while multiresistant antimicrobial phenotypes were observed among all species. The prevalence of resistance among isolates of E. faecalis was comparatively higher among lincosamide, macrolide, and tetracycline antimicrobials, while isolates of E. faecium were observed to be more frequently resistant to fluoroquinolones and penicillins. Notably, 63% of the E. faecium isolates were resistant to the streptogramin quinupristin-dalfopristin, while high-level gentamicin resistance was observed only among the E. faecalis population, of which 7% of the isolates were resistant. The primary observations are that enterococci can be frequently isolated from the poultry production environment and can be multiresistant to antimicrobials used in human medicine. The high frequency with which resistant enterococci are isolated from this environment suggests that these organisms might be useful as sentinels to monitor the development of resistance resulting from the usage of antimicrobial agents in animal production. PMID:15466544

  7. 21 CFR 880.6885 - Liquid chemical sterilants/high level disinfectants.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Liquid chemical sterilants/high level... and Personal Use Miscellaneous Devices § 880.6885 Liquid chemical sterilants/high level disinfectants. (a) Identification. A liquid chemical sterilant/high level disinfectant is a germicide that...

  8. 21 CFR 880.6885 - Liquid chemical sterilants/high level disinfectants.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Liquid chemical sterilants/high level... and Personal Use Miscellaneous Devices § 880.6885 Liquid chemical sterilants/high level disinfectants. (a) Identification. A liquid chemical sterilant/high level disinfectant is a germicide that...

  9. 21 CFR 880.6885 - Liquid chemical sterilants/high level disinfectants.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Liquid chemical sterilants/high level... and Personal Use Miscellaneous Devices § 880.6885 Liquid chemical sterilants/high level disinfectants. (a) Identification. A liquid chemical sterilant/high level disinfectant is a germicide that...

  10. 21 CFR 880.6885 - Liquid chemical sterilants/high level disinfectants.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Liquid chemical sterilants/high level... and Personal Use Miscellaneous Devices § 880.6885 Liquid chemical sterilants/high level disinfectants. (a) Identification. A liquid chemical sterilant/high level disinfectant is a germicide that...

  11. 21 CFR 880.6885 - Liquid chemical sterilants/high level disinfectants.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Liquid chemical sterilants/high level... and Personal Use Miscellaneous Devices § 880.6885 Liquid chemical sterilants/high level disinfectants. (a) Identification. A liquid chemical sterilant/high level disinfectant is a germicide that...

  12. 40 CFR 1065.725 - High-level ethanol-gasoline blends.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false High-level ethanol-gasoline blends... Calibration Standards § 1065.725 High-level ethanol-gasoline blends. For testing vehicles capable of operating on a high-level ethanol-gasoline blend, create a test fuel as follows: (a) Add ethanol to an E10...

  13. Influence of different medium components on the in vitro activity of the growth-promoting antibiotic flavomycin against enterococci.

    PubMed

    Butaye, P; Devriese, L A; Haesebrouck, F

    2000-11-01

    The growth-promoting antibiotic flavomycin (also called bambermycin, flavophospholipol and moenomycin) has a complex spectrum of activity against enterococci, with some species being naturally resistant and others susceptible. In this study, proteins added to Mueller-Hinton II medium had a strong deleterious effect on the activity of flavomycin, glucose had no effect and starch decreased the activity of flavomycin. The fatty substances Tween 80 and tributyrin increased the activity of flavomycin for several enterococcal species. Slight differences in the composition of the susceptibility test medium affected the MIC results obtained, indicating that strict standardization of the test medium is necessary.

  14. Infections due to gentamicin-resistant Staphylococcus aureus strain in a nursery for neonatal infants.

    PubMed Central

    Vogel, L; Nathan, C; Sweeney, H M; Kabins, S A; Cohen, S

    1978-01-01

    An apparently homogeneous strain of Staphylococcus aureus resistant to gentamicin (Gmr), kanamycin, tobramycin, and sisomicin, but susceptible to amikacin and netilmicin, caused multiple infections in neonatal infants in a special care nursery. Nasal cultures revealed a high rate of carriage of the Gmr staphylococcus in infants without clinical infection. Segregating patients according to a modified cohort system and use of careful aseptic techniques led to apparent elimination of the Gmr strain. The resistance to aminoglycosides in this strain was mediated by an aminoglycoside 6'-N-acetyltransferase and a gentamicin phosphotransferase. Genetic determinants for these enzymes were borne on a circular covalently closed plasmid of approximately 11 megadaltons. These resistance determinants closely resemble those found in isolates of S. aureus that have caused nosocomial infections in patients in Europe. PMID:263886

  15. Occurrence of airborne vancomycin- and gentamicin-resistant bacteria in various hospital wards in Isfahan, Iran

    PubMed Central

    Mirhoseini, Seyed Hamed; Nikaeen, Mahnaz; Khanahmad, Hossein; Hassanzadeh, Akbar

    2016-01-01

    Background: Airborne transmission of pathogenic resistant bacteria is well recognized as an important route for the acquisition of a wide range of nosocomial infections in hospitals. The aim of this study was to determine the prevalence of airborne vancomycin and gentamicin (VM and GM) resistant bacteria in different wards of four educational hospitals. Materials and Methods: A total of 64 air samples were collected from operating theater (OT), Intensive Care Unit (ICU), surgery ward, and internal medicine ward of four educational hospitals in Isfahan, Iran. Airborne culturable bacteria were collected using all glass impingers. Samples were analyzed for the detection of VM- and GM-resistant bacteria. Results: The average level of bacteria ranged from 99 to 1079 CFU/m3. The highest level of airborne bacteria was observed in hospital 4 (628 CFU/m3) and the highest average concentration of GM- and VM-resistant airborne bacteria were found in hospital 3 (22 CFU/m3). The mean concentration of airborne bacteria was the lowest in OT wards and GM- and VM-resistant airborne bacteria were not detected in this ward of hospitals. The highest prevalence of antibiotic-resistant airborne bacteria was observed in ICU ward. There was a statistically significant difference for the prevalence of VM-resistant bacteria between hospital wards (P = 0.012). Conclusion: Our finding showed that the relatively high prevalence of VM- and GM-resistant airborne bacteria in ICUs could be a great concern from the point of view of patients' health. These results confirm the necessity of application of effective control measures which significantly decrease the exposure of high-risk patients to potentially airborne nosocomial infections. PMID:27656612

  16. Effects of In-Feed Copper, Chlortetracycline, and Tylosin on the Prevalence of Transferable Copper Resistance Gene, tcrB, Among Fecal Enterococci of Weaned Piglets.

    PubMed

    Amachawadi, Raghavendra G; Scott, H Morgan; Vinasco, Javier; Tokach, Mike D; Dritz, Steve S; Nelssen, Jim L; Nagaraja, Tiruvoor G

    2015-08-01

    Heavy metals, such as copper, are increasingly supplemented in swine diets as an alternative to antibiotics to promote growth. Enterococci, a common gut commensal, acquire plasmid-borne, transferable copper resistance (tcrB) gene-mediated resistance to copper. The plasmid also carried resistance genes to tetracyclines and macrolides. The potential genetic link between copper and antibiotic resistance suggests that copper supplementation may exert a selection pressure for antimicrobial resistance. Therefore, a longitudinal study was conducted to investigate the effects of in-feed copper, chlortetracycline, and tylosin alone or in combination on the selection and co-selection of antimicrobial-resistant enterococci. The study included 240 weaned piglets assigned randomly to 6 dietary treatment groups: control, copper, chlortetracycline, tylosin, copper and chlortetracycline, and copper and tylosin. Feces were collected before (day 0), during (days 7, 14, 21), and after (days 28 and 35) initiating treatment, and enterococcal isolates were obtained from each fecal sample and tested for genotypic and phenotypic resistance to copper and antibiotics. A total of 2592 enterococcal isolates were tested for tcrB by polymerase chain reaction. The overall prevalence of tcrB-positive enterococci was 14.3% (372/2592). Among the tcrB-positive isolates, 331 were Enterococcus faecium and 41 were E. faecalis. All tcrB-positive isolates contained both erm(B) and tet(M) genes. The median minimum inhibitory concentration of copper for tcrB-negative and tcrB-positive enterococci was 6 and 18 mM, respectively. The majority of isolates (95/100) were resistant to multiple antibiotics. In conclusion, supplementing copper or antibiotics alone did not increase copper-resistant enterococci; however, supplementing antibiotics with copper increased the prevalence of the tcrB gene among fecal enterococci of piglets.

  17. Mortality in Kittens Is Associated with a Shift in Ileum Mucosa-Associated Enterococci from Enterococcus hirae to Biofilm-Forming Enterococcus faecalis and Adherent Escherichia coli

    PubMed Central

    Ghosh, Anuradha; Borst, Luke; Stauffer, Stephen H.; Suyemoto, Mitsu; Moisan, Peter; Zurek, Ludek

    2013-01-01

    Approximately 15% of foster kittens die before 8 weeks of age, with most of these kittens demonstrating clinical signs or postmortem evidence of enteritis. While a specific cause of enteritis is not determined in most cases, these kittens are often empirically administered probiotics that contain enterococci. The enterococci are members of the commensal intestinal microbiota but also can function as opportunistic pathogens. Given the complicated role of enterococci in health and disease, it would be valuable to better understand what constitutes a “healthy” enterococcal community in these kittens and how this microbiota is impacted by severe illness. In this study, we characterized the ileum mucosa-associated enterococcal community of 50 apparently healthy and 50 terminally ill foster kittens. In healthy kittens, Enterococcus hirae was the most common species of ileum mucosa-associated enterococci and was often observed to adhere extensively to the small intestinal epithelium. These E. hirae isolates generally lacked virulence traits. In contrast, non-E. hirae enterococci, notably Enterococcus faecalis, were more commonly isolated from the ileum mucosa of kittens with terminal illness. Isolates of E. faecalis had numerous virulence traits and multiple antimicrobial resistances. Moreover, the attachment of Escherichia coli to the intestinal epithelium was significantly associated with terminal illness and was not observed in any kitten with adherent E. hirae. These findings identify a significant difference in the species of enterococci cultured from the ileum mucosa of kittens with terminal illness compared to the species cultured from healthy kittens. In contrast to prior case studies that associated enteroadherent E. hirae with diarrhea in young animals, these controlled studies identified E. hirae as more often isolated from healthy kittens and adherence of E. hirae as more common and extensive in healthy kittens than in sick kittens. PMID:23966487

  18. Mortality in kittens is associated with a shift in ileum mucosa-associated enterococci from Enterococcus hirae to biofilm-forming Enterococcus faecalis and adherent Escherichia coli.

    PubMed

    Ghosh, Anuradha; Borst, Luke; Stauffer, Stephen H; Suyemoto, Mitsu; Moisan, Peter; Zurek, Ludek; Gookin, Jody L

    2013-11-01

    Approximately 15% of foster kittens die before 8 weeks of age, with most of these kittens demonstrating clinical signs or postmortem evidence of enteritis. While a specific cause of enteritis is not determined in most cases, these kittens are often empirically administered probiotics that contain enterococci. The enterococci are members of the commensal intestinal microbiota but also can function as opportunistic pathogens. Given the complicated role of enterococci in health and disease, it would be valuable to better understand what constitutes a "healthy" enterococcal community in these kittens and how this microbiota is impacted by severe illness. In this study, we characterized the ileum mucosa-associated enterococcal community of 50 apparently healthy and 50 terminally ill foster kittens. In healthy kittens, Enterococcus hirae was the most common species of ileum mucosa-associated enterococci and was often observed to adhere extensively to the small intestinal epithelium. These E. hirae isolates generally lacked virulence traits. In contrast, non-E. hirae enterococci, notably Enterococcus faecalis, were more commonly isolated from the ileum mucosa of kittens with terminal illness. Isolates of E. faecalis had numerous virulence traits and multiple antimicrobial resistances. Moreover, the attachment of Escherichia coli to the intestinal epithelium was significantly associated with terminal illness and was not observed in any kitten with adherent E. hirae. These findings identify a significant difference in the species of enterococci cultured from the ileum mucosa of kittens with terminal illness compared to the species cultured from healthy kittens. In contrast to prior case studies that associated enteroadherent E. hirae with diarrhea in young animals, these controlled studies identified E. hirae as more often isolated from healthy kittens and adherence of E. hirae as more common and extensive in healthy kittens than in sick kittens.

  19. Transport and persistence of tylosin-resistant enterococci, genes, and tylosin in soil and drainage water from fields receiving Swine manure.

    PubMed

    Garder, Jason L; Moorman, Thomas B; Soupir, Michelle L

    2014-07-01

    Land application of manure from tylosin-treated swine introduces tylosin, tylosin-resistant enterococci, and erythromycin resistant rRNA methylase () genes, which confer resistance to tylosin. This study documents the persistence and transport of tylosin-resistant enterococci, genes, and tylosin in tile-drained chisel plow and no-till agricultural fields treated with liquid swine manure in alternating years. Between 70 and 100% of the enterococci in manure were resistant to tylosin and B concentrations exceeded 10 copies g manure, while the mean F concentrations exceeded 10 copies g manure (T was not detected). The mean concentration of tylosin was 73 ng g manure. Soil collected from the manure injection band closely following application contained >10 copies g soil of both B and F in 2010 and >10 copies g soil after the 2011 application compared to 3 × 10 to 3 × 10 copies g soil in the no-manure control plots. Gene abundances declined over the subsequent 2-yr period to levels similar to those in the no-manure controls. Concentrations of enterococci in tile water were low, while tylosin-resistant enterococci were rarely detected. In approximately 75% of tile water samples, B was detected, and F was detected in 30% of tile water samples, but levels of these genes were not elevated due to manure application, and no difference was found between tillage practices. These results show that tylosin usage increased the short-term occurrence of tylosin-resistant enterococci, genes, and tylosin in soils but had minimal effect on tile drainage water quality in years of average to below average precipitation.

  20. Rapid characterization schemes for surveillance isolates of vancomycin-resistant enterococci.

    PubMed

    Sahm, D F; Free, L; Smith, C; Eveland, M; Mundy, L M

    1997-08-01

    Surveillance cultures for vancomycin-resistant enterococci (VRE) and subsequent characterization of the isolates can be extremely burdensome and difficult. Therefore, efficient and reliable schemes for the characterization of surveillance isolates are needed. In this study, a commercial agar (bile esculin azide agar with 6 microg of vancomycin per ml [BEAA]; Remel, Lenexa, Kans.) was used in the initial screening step to establish relatively rapid (i.e., in < or = 24 h from the time of isolation) phenotype-based and PCR-based schemes for the detection and characterization of VRE. The phenotype-based scheme included Gram staining of growth on BEAA and subculture of cocci on sheep blood agar plates for vancomycin disk diffusion and pyrazinamidase (PYR) testing. For the PCR scheme, inocula for van gene detection were taken directly from the BEAA plates. The phenotypic approach was applied to 378 surveillance cultures that yielded growth on BEAA. Gram staining quickly eliminated gram-positive bacilli from further testing, and a negative PYR test classified 25 additional isolates as probable pediococci. A positive PYR test reliably identified 121 single-patient VRE isolates that included 83 Enterococcus faecium, 33 E. gallinarum, and 5 E. casseliflavus strains. The vancomycin inhibition zone size clearly distinguished VanA and VanB strains from VanC strains within 24 h of BEAA isolation. All VanA and VanB strains failed to produce zones of >6 mm, while only one VanC strain produced a zone of < 15 mm. Challenging this phenotypic scheme with 47 stock VRE isolates produced similar findings. In direct PCR analyses, false-negative vanA and vanB results occurred with 12% of the specimens. Many of the false-negative reactions also failed to produce an internal control product, which underscores the need for including control primers when a PCR scheme is used. In summary, the phenotype- and the PCR-based schemes provide efficient methods for characterizing VRE within 24 h of

  1. Quantitative detection and identification of tyramine-producing enterococci and lactobacilli in cheese by multiplex qPCR.

    PubMed

    Ladero, Victor; Fernández, María; Cuesta, Isabel; Alvarez, Miguel A

    2010-10-01

    Tyramine is the most abundant biogenic amine in fermented dairy products, in which it is produced through the microbial enzymatic decarboxylation of tyrosine. This activity has been detected in a variety of lactic acid bacteria mainly belonging to the genera Enterococcus and Lactobacillus. This paper describes a culture-independent qPCR method, based on the specific amplification of the tdc gene, for the detection, quantification and identification of bacteria with the ability to produce tyramine. This method was found to be specific and to show a wide dynamic range, thus allowing the quantification of these tdc+ bacterial groups among the complex microbiota of cheese. tdc qPCR was used to follow the development of tdc+ microbiota during the manufacture of a blue-veined cheese (Cabrales) made from raw milk. In this type of cheese, tdc+ enterococci seem to be responsible for the high concentrations of tyramine detected. The method was also used to identify and quantify tdc+ enterococci and lactobacilli in 18 commercially available cheeses. Different types and numbers of these microorganisms were found. Their relationships with the concentration of tyramine and technological factors are discussed.

  2. Fecal carriage of vancomycin-resistant enterococci in hospitalized patients and those living in the community in The Netherlands.

    PubMed Central

    Endtz, H P; van den Braak, N; van Belkum, A; Kluytmans, J A; Koeleman, J G; Spanjaard, L; Voss, A; Weersink, A J; Vandenbroucke-Grauls, C M; Buiting, A G; van Duin, A; Verbrugh, H A

    1997-01-01

    In order to determine the prevalence of vancomycin-resistant enterococci (VRE) in The Netherlands, 624 hospitalized patients from intensive care units or hemato-oncology wards in nine hospitals and 200 patients living in the community were screened for VRE colonization. Enterococci were found in 49% of the hospitalized patients and in 80% of the patients living in the community. Of these strains, 43 and 32%, respectively, were Enterococcus faecium. VRE were isolated from 12 of 624 (2%) and 4 of 200 (2%) hospitalized patients and patients living in the community, respectively. PCR analysis of these 16 strains and 11 additional clinical VRE isolates from one of the participating hospitals revealed 24 vanA gene-containing, 1 vanB gene-containing, and 2 vanC1 gene-containing strains. All strains were cross-resistant to avoparcin but were sensitive to the novel glycopeptide antibiotic LY333328. Genotyping of the strains by arbitrarily primed PCR and pulsed-field gel electrophoresis revealed a high degree of genetic heterogeneity. This underscores a lack of hospital-driven endemicity of VRE clones. It is suggested that the VRE in hospitalized patients have originated from unknown sources in the community. PMID:9399488

  3. In vitro activity of daptomycin in combination with β-lactams, gentamicin, rifampin, and tigecycline against daptomycin-nonsusceptible enterococci.

    PubMed

    Hindler, Janet A; Wong-Beringer, Annie; Charlton, Carmen L; Miller, Shelley A; Kelesidis, Theodoros; Carvalho, Marissa; Sakoulas, George; Nonejuie, Poochit; Pogliano, Joseph; Nizet, Victor; Humphries, Romney

    2015-07-01

    Enterococci that are nonsusceptible (NS; MIC > 4 μg/ml) to daptomycin are an emerging clinical concern. The synergistic combination of daptomycin plus beta-lactams has been shown to be effective against vancomycin-resistant Enterococcus (VRE) species in vitro. This study systematically evaluated by in vitro time-kill studies the effect of daptomycin in combination with ampicillin, cefazolin, ceftriaxone, ceftaroline, ertapenem, gentamicin, tigecycline, and rifampin, for a collection of 9 daptomycin-NS enterococci that exhibited a broad range of MICs and different resistance-conferring mutations. We found that ampicillin plus daptomycin yielded the most consistent synergy but did so only for isolates with mutations to the liaFSR system. Daptomycin binding was found to be enhanced by ampicillin in a representative isolate with such mutations but not for an isolate with mutation to the yycFGHIJ system. In contrast, ampicillin enhanced the killing of the LL-37 human antimicrobial peptide against daptomycin-NS E. faecium with either the liaFSR or yycFGHIJ mutation. Antagonism was noted only for rifampin and tigecycline and only for 2 or 3 isolates. These data add support to the growing body of evidence indicating that therapy combining daptomycin and ampicillin may be helpful in eradicating refractory VRE infections.

  4. Vancomycin resistant enterococci (VRE) still persist in slaughtered poultry in hungary 8 years after the ban on avoparcin.

    PubMed

    Ghidán, A; Dobay, Orsolya; Kaszanyitzky, Eva J; Samu, Péterné; Amyes, S G B; Nagy, K; Rozgonyi, F

    2008-12-01

    In this report we examined the glycopeptide susceptibility of enterococci, isolated in 2005, from slaughtered animals, within the confines of Hungarian Antibiotic Resistance Monitoring System. We determined the presence of the van genes as well as their genetic relatedness in enterococci from poultry. Enterococcus sp. strains (n=175) were collected from intestinal samples of slaughtered poultry in 2005. The origin of the samples was registered at county level. After screening the strains with 30 mg vancomycin disc 19 (86%) intermediate resistant and 4 (3%) fully resistant strains were found. The distribution of minimum inhibitory concentration (MIC)-values among 23 enterococcus strains which were intermediate or resistant to vancomycin were 0.25 mg/L (4.4%), 2 mg/L (8.6%), 4 mg/L (8.6%), 8 mg/L (61%), 16 mg/L (8.6%) and 256 mg/L (8.6%). The MICs of teicoplanin were 0.25 mg/L (4.3%), 1 (8.6%), 4 mg/L (78.3%), 16 mg/L (4.3%) and 256 mg/L (4.3%). The two most vancomycin-resistant strains were vanA carriers (1 E. faecalis and 1 E. faeciuum). The farms that produced these strains can be reservoirs of VRE and the affected farms should change the technology of disinfection and breeding in order to prevent the emergence of high numbers of human VRE isolates in Hungary.

  5. Modeling the transport and inactivation of E. coli and enterococci in the near-shore region of Lake Michigan

    USGS Publications Warehouse

    Liu, L.; Phanikumar, M.S.; Molloy, S.L.; Whitman, R.L.; Shively, D.A.; Nevers, M.B.; Schwab, D.J.; Rose, J.B.

    2006-01-01

    To investigate the transport and fate of fecal pollution at Great Lakes beaches and the health risks associated with swimming, the near-shore waters of Lake Michigan and two tributaries discharging into it were examined for bacterial indicators of human fecal pollution. The enterococcus human fecal pollution marker, which targets a putative virulence factorthe enterococcal surface protein (esp) in Enterococcus faecium, was detected in 2/28 samples (7%) in the tributaries draining into Lake Michigan and in 6/30 samples (20%) in Lake Michigan beaches. This was indicative of human fecal pollution being transported in the tributaries and occurrence at Lake Michigan beaches. To understand the relative importance of different processes influencing pollution transport and inactivation, a finite-element model of surf-zone hydrodynamics (coupled with models for temperature, E. coli and enterococci) was used. Enterococci appear to survive longer than E. coli, which was described using an overall first-order inactivation coefficient in the range 0.5−2.0 per day. Our analysis suggests that the majority of fecal indicator bacteria variation can be explained based on loadings from the tributaries. Sunlight is a major contributor to inactivation in the surf-zone and the formulation based on sunlight, temperature and sedimentation is preferred over the first-order inactivation formulation.

  6. Phenylthiazole Antibacterial Agents Targeting Cell Wall Synthesis Exhibit Potent Activity in Vitro and in Vivo against Vancomycin-Resistant Enterococci.

    PubMed

    Mohammad, Haroon; Younis, Waleed; Chen, Lu; Peters, Christine E; Pogliano, Joe; Pogliano, Kit; Cooper, Bruce; Zhang, Jianan; Mayhoub, Abdelrahman; Oldfield, Eric; Cushman, Mark; Seleem, Mohamed N

    2017-03-23

    The emergence of antibiotic-resistant bacterial species, such as vancomycin-resistant enterococci (VRE), necessitates the development of new antimicrobials. Here, we investigate the spectrum of antibacterial activity of three phenylthiazole-substituted aminoguanidines. These compounds possess potent activity against VRE, inhibiting growth of clinical isolates at concentrations as low as 0.5 μg/mL. The compounds exerted a rapid bactericidal effect, targeting cell wall synthesis. Transposon mutagenesis suggested three possible targets: YubA, YubB (undecaprenyl diphosphate phosphatase (UPPP)), and YubD. Both UPPP as well as undecaprenyl diphosphate synthase were inhibited by compound 1. YubA and YubD are annotated as transporters and may also be targets because 1 collapsed the proton motive force in membrane vesicles. Using Caenorhabditis elegans, we demonstrate that two compounds (1, 3, at 20 μg/mL) retain potent activity in vivo, significantly reducing the burden of VRE in infected worms. Taken altogether, the results indicate that compounds 1 and 3 warrant further investigation as novel antibacterial agents against drug-resistant enterococci.

  7. Relationship and variation of qPCR and culturable enterococci estimates in ambient surface waters are predictable

    USGS Publications Warehouse

    Whitman, Richard L.; Ge, Zhongfu; Nevers, Meredith B.; Boehm, Alexandria B.; Chern, Eunice C.; Haugland, Richard A.; Lukasik, Ashley M.; Molina, Marirosa; Przybyla-Kelly, Kasia; Shively, Dawn A.; White, Emily M.; Zepp, Richard G.; Byappanahalli, Muruleedhara N.

    2010-01-01

    The quantitative polymerase chain reaction (qPCR) method provides rapid estimates of fecal indicator bacteria densities that have been indicated to be useful in the assessment of water quality. Primarily because this method provides faster results than standard culture-based methods, the U.S. Environmental Protection Agency is currently considering its use as a basis for revised ambient water quality criteria. In anticipation of this possibility, we sought to examine the relationship between qPCR-based and culture-based estimates of enterococci in surface waters. Using data from several research groups, we compared enterococci estimates by the two methods in water samples collected from 37 sites across the United States. A consistent linear pattern in the relationship between cell equivalents (CCE), based on the qPCR method, and colony-forming units (CFU), based on the traditional culturable method, was significant (P 10CFU > 2.0/100 mL) while uncertainty increases at lower CFU values. It was further noted that the relative error in replicated qPCR estimates was generally higher than that in replicated culture counts even at relatively high target levels, suggesting a greater need for replicated analyses in the qPCR method to reduce relative error. Further studies evaluating the relationship between culture and qPCR should take into account analytical uncertainty as well as potential differences in results of these methods that may arise from sample variability, different sources of pollution, and environmental factors.

  8. 23S rRNA gene-based enterococci community signatures in Lake Pontchartrain, Louisiana, USA, following urban runoff inputs after Hurricane Katrina.

    PubMed

    Bae, Hee-Sung; Hou, Aixin

    2013-02-01

    Little is known about the impacts of fecal polluted urban runoff inputs on the structure of enterococci communities in estuarine waters. This study employed a 23S rRNA gene-based polymerase chain reaction (PCR) assay with newly designed genus-specific primers, Ent127F-Ent907R, to determine the possible impacts of Hurricane Katrina floodwaters via the 17th Street Canal discharge on the community structure of enterococci in Lake Pontchartrain. A total of 94 phylotypes were identified through the restriction fragment length polymorphism (RFLP) screening of 494 clones while only 8 phylotypes occurred among 88 cultivated isolates. Sequence analyses of representative phylotypes and their temporal and spatial distribution in the lake and the canal indicated the Katrina floodwater input introduced a large portion of Enterococcus flavescens, Enterococcus casseliflavus, and Enterococcus dispar into the lake; typical fecal groups Enterococcus faecium, Enterococcus durans, Enterococcus hirae, and Enterococcus mundtii were detected primarily in the floodwater-impacted waters. This study provides a global picture of enterococci in estuarine waters impacted by Hurricane Katrina-derived urban runoff. It also demonstrates the culture-independent PCR approach using 23S rRNA gene as a molecular marker could be a good alternative in ecological studies of enterococci in natural environments to overcome the limitation of conventional cultivation methods.

  9. Evaluation of Commercial Cell Preparations as Sources of Calibration Standards for Real-Time qPCR Analysis of Enterococci in Recreational Waters

    EPA Science Inventory

    In response to the Beach Act, the U.S. EPA has developed a quantitative PCR (qPCR) method for enterococci that meets requirements for rapid, risk-based water quality assessments of recreational waters. Widespread implementation of this method will require that different laborator...

  10. Standardization of enterococci density estimates by EPA qPCR methods and comparison of beach action value exceedances in river waters with culture methods

    EPA Science Inventory

    The U.S.EPA has published recommendations for calibrator cell equivalent (CCE) densities of enterococci in recreational waters determined by a qPCR method in its 2012 Recreational Water Quality Criteria (RWQC). The CCE quantification unit stems from the calibration model used to ...

  11. Loss of Antibiotic Tolerance in Sod-Deficient Mutants Is Dependent on the Energy Source and Arginine Catabolism in Enterococci

    PubMed Central

    Ladjouzi, Rabia; Bizzini, Alain; van Schaik, Willem; Zhang, Xinglin; Rincé, Alain; Benachour, Abdellah

    2015-01-01

    ABSTRACT Enterococci are naturally tolerant to typically bactericidal cell wall-active antibiotics, meaning that their growth is inhibited but they are not killed even when exposed to a high concentration of the drug. The molecular reasons for this extraordinary tolerance are still incompletely understood. Previous work showed that resistance to killing collapsed specifically in mutants affected in superoxide dismutase (Sod) activity, arguing that bactericidal antibiotic treatment led to induction of a superoxide burst. In the present work, we show that loss of antibiotic tolerance in ΔsodA mutants of pathogenic enterococci is dependent on the energy source present during antibiotic treatment. Hexoses induce greater killing than the pentose ribose, and no killing was observed with glycerol as the energy source. These results point to glycolytic reactions as crucial for antibiotic-mediated killing of ΔsodA mutants. A transposon mutant library was constructed in Enterococcus faecalis ΔsodA mutants and screened for restored tolerance of vancomycin. Partially restored tolerance was observed in mutants with transposon integrations into intergenic regions upstream of regulators implicated in arginine catabolism. In these mutants, the arginine deiminase operon was highly upregulated. A model for the action of cell wall-active antibiotics in tolerant and nontolerant bacteria is proposed. IMPORTANCE Antibiotic tolerance is a serious clinical concern, since tolerant bacteria have considerably increased abilities to resist killing by bactericidal drugs. Using enterococci as models for highly antibiotic-tolerant pathogens, we showed that tolerance of these bacteria is linked to their superoxide dismutase (Sod), arguing that bactericidal antibiotics induce generation of reactive oxygen species inside cells. Wild-type strains are tolerant because they detoxify these deleterious molecules by the activity of Sod, whereas Sod-deficient strains are killed. This study showed that

  12. Distribution of aminoglycoside resistance genes in recent clinical isolates of Enterococcus faecalis, Enterococcus faecium and Enterococcus avium.

    PubMed Central

    Kobayashi, N.; Alam, M.; Nishimoto, Y.; Urasawa, S.; Uehara, N.; Watanabe, N.

    2001-01-01

    Aminoglycoside modifying enzymes (AMEs) are major factors which confer aminoglycoside resistance on bacteria. Distribution of genes encoding seven AMEs was investigated by multiplex PCR for 279 recent clinical isolates of enterococci derived from a university hospital in Japan. The aac(6')-aph(2"), which is related to high level gentamicin resistance, was detected at higher frequency in Enterococcus faecalis (42.5%) than in Enterococcus faecium (4.3%). Almost half of E. faecalis and E. faecium isolates possessed ant(6)-Ia and aph(3')-IIIa. The profile of AME gene(s) detected most frequently in individual strains of E. faecalis was aac(6')aph(2") + ant(6)-Ia + aph(3')-IIIa, and isolates with this profile showed high level resistance to both gentamicin and streptomycin. In contrast, AME gene profiles of aac(6')-Ii+ ant(6)-Ia+aph(3')-IIIa, followed by aac(6')-Ii alone, were predominant in E. faecium. Only one AME gene profile of ant(6)-Ia+aph(3')-IIIa was found in Enterococcus avium. The ant(4')-Ia and ant(9)-Ia, which have been known to be distributed mostly among Staphylococcus aureus strains, were detected in a few enterococcal strains. An AME gene aph(2")-Ic was not detected in any isolates of the three enterococcal species. These findings indicated a variety of distribution profiles of AME genes among enterococci in our study site. PMID:11349969

  13. Occurrence and growth characteristics of Escherichia coli and enterococci within the accumulated fluid of the northern pitcher plant (Sarracenia purpurea L.).

    PubMed

    Whitman, Richard L; Byers, Stacey E; Shively, Dawn A; Ferguson, Donna M; Byappanahalli, Muruleedhara

    2005-12-01

    Sarracenia purpurea L., a carnivorous bog plant (also known as the pitcher plant), represents an excellent model of a well-defined, self-contained ecosystem; the individual pitchers of the plant serve as a microhabitat for a variety of micro- and macro-organisms. Previously, fecal indicator bacteria (Escherichia coli and enterococci) were shown as incidental contaminants in pitcher fluid; however, whether their occurrence in pitcher fluid is incidental or common has not been established. The purpose of this study was to investigate the occurrence, distribution, and growth potential of E. coli and enterococci in pitcher plant fluid from a protected bog in northwest Indiana. Escherichia coli and enterococci were recovered in pitcher fluids (n=43 plants), with mean densities (log CFU mL-1) of 1.28+/-0.23 and 1.97+/-0.27, respectively. In vitro experiments showed that E. coli growth in fluid not containing insects or indigenous organisms was directly proportional to the fluid concentration (growth was 10-fold in 24 h in 100% fluid); however, in the presence of other indigenous organisms, E. coli and enterococci were only sustained for 5 days at 26 degrees C. Pulsed-field gel electrophoresis (PFGE) analysis showed that the plant Enterococcus faecalis isolates were genetically distinct from the human isolates; identical PFGE patterns were observed among plant isolates that fell into one of six clonal groups. These findings suggest that (i) E. coli and enterococci occurrence in pitcher plants is rather common in the bog studied, although their originating source is unclear, and (ii) the pitcher fluid contains adequate nutrients, especially carbon and energy sources, to promote the growth of indicator bacteria; however, under natural conditions, the biotic factors (e.g., competition for nutrients) may restrict their growth.

  14. Occurrence and growth characteristics of Escherichia coli and enterococci within the accumulated fluid of the northern pitcher plant (Sarracenia purpurea L.)

    USGS Publications Warehouse

    Whitman, Richard L.; Byers, Stacey E.; Shively, Dawn A.; Ferguson, Donna M.; Byappanahalli, Muruleedhara N.

    2005-01-01

    Sarracenia purpurea L., a carnivorous bog plant (also known as the pitcher plant), represents an excellent model of a well-defined, self-contained ecosystem; the individual pitchers of the plant serve as a microhabitat for a variety of micro- and macro-organisms. Previously, fecal indicator bacteria (Escherichia coli and enterococci) were shown as incidental contaminants in pitcher fluid; however, whether their occurrence in pitcher fluid is incidental or common has not been established. The purpose of this study was to investigate the occurrence, distribution, and growth potential of E. coli and enterococci in pitcher plant fluid from a protected bog in northwest Indiana. Escherichia coli and enterococci were recovered in pitcher fluids (n = 43 plants), with mean densities (log CFU mL-1) of 1.28 ± 0.23 and 1.97 ± 0.27, respectively. In vitro experiments showed that E. coli growth in fluid not containing insects or indigenous organisms was directly proportional to the fluid concentration (growth was 10-fold in 24 h in 100% fluid); however, in the presence of other indigenous organisms, E. coli and enterococci were only sustained for 5 days at 26 °C. Pulsed-field gel electrophoresis (PFGE) analysis showed that the plant Enterococcus faecalis isolates were genetically distinct from the human isolates; identical PFGE patterns were observed among plant isolates that fell into one of six clonal groups. These findings suggest that (i) E. coli and enterococci occurrence in pitcher plants is rather common in the bog studied, although their originating source is unclear, and (ii) the pitcher fluid contains adequate nutrients, especially carbon and energy sources, to promote the growth of indicator bacteria; however, under natural conditions, the biotic factors (e.g., competition for nutrients) may restrict their growth.

  15. Alternatives Generation and Analysis for Heat Removal from High Level Waste Tanks

    SciTech Connect

    WILLIS, W.L.

    2000-06-15

    This document addresses the preferred combination of design and operational configurations to provide heat removal from high-level waste tanks during Phase 1 waste feed delivery to prevent the waste temperature from exceeding tank safety requirement limits. An interim decision for the preferred method to remove the heat from the high-level waste tanks during waste feed delivery operations is presented herein.

  16. Hi-LAB: A New Measure of Aptitude for High-Level Language Proficiency

    ERIC Educational Resources Information Center

    Linck, Jared A.; Hughes, Meredith M.; Campbell, Susan G.; Silbert, Noah H.; Tare, Medha; Jackson, Scott R.; Smith, Benjamin K.; Bunting, Michael F.; Doughty, Catherine J.

    2013-01-01

    Few adult second language (L2) learners successfully attain high-level proficiency. Although decades of research on beginning to intermediate stages of L2 learning have identified a number of predictors of the rate of acquisition, little research has examined factors relevant to predicting very high levels of L2 proficiency. The current study,…

  17. Inspection and evaluation of Nuclear Fuel Services high-level waste storage system, program plan

    NASA Astrophysics Data System (ADS)

    1980-01-01

    Information concerning the condition of the high-level waste tanks at the Western New York State Nuclear Service center near West Valley, New York is presented. This information is to be used in evaluating the safety of continued storage and in the development of alternatives for final disposition of the high-level waste.

  18. 78 FR 14840 - U.S.-EU High Level Regulatory Cooperation Forum-Stakeholder Session

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-07

    ... BUDGET U.S.-EU High Level Regulatory Cooperation Forum--Stakeholder Session AGENCY: Office of Management... will hold a public meeting of the U.S.-EU High Level Regulatory Cooperation Forum (the ``Forum'') in...-cooperation-forum . Oral Presentations: Any persons wishing to present an oral statement at the public...

  19. 78 FR 70281 - United States-Mexico High Level Economic Dialogue

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-25

    ... United States-Mexico High Level Economic Dialogue AGENCY: International Trade Administration, Commerce... Register notice on the United States-Mexico High Level Economic Dialogue. DATES: The agency must receive... largest export market and third largest overall trading partner. The United States, in turn, is...

  20. High level language for measurement complex control based on the computer E-100I

    NASA Technical Reports Server (NTRS)

    Zubkov, B. V.

    1980-01-01

    A high level language was designed to control the process of conducting an experiment using the computer "Elektrinika-1001". Program examples are given to control the measuring and actuating devices. The procedure of including these programs in the suggested high level language is described.

  1. Characteristics Data Base: Programmer's guide to the High-Level Waste Data Base

    SciTech Connect

    Jones, K.E. ); Salmon, R. )

    1990-08-01

    The High-Level Waste Data Base is a menu-driven PC data base developed as part of OCRWM's technical data base on the characteristics of potential repository wastes, which also includes spent fuel and other materials. This programmer's guide completes the documentation for the High-Level Waste Data Base, the user's guide having been published previously. 3 figs.

  2. Susceptibility of Glycopeptide-Resistant Enterococci to Linezolid, Quinupristin/dalfopristin, Tigecycline and Daptomycin in a Tertiary Greek Hospital

    PubMed Central

    Dimopoulou, Dimitra; Mantadakis, Elpis

    2014-01-01

    We investigated the antibiotic susceptibility of glycopeptide-resistant enterococci (GRE). Seventy consecutive GRE were tested. Sixty-two isolates were identified as Enterococcus faecium (88.6%), and 8 (11.4%) as Enterococcus faecalis. All strains were susceptible to linezolid and daptomycin, while 17.1% (12/70) and 11.4% (8/70) were resistant to quinupristin/dalfopristin (QD) and tigecycline, respectively. All E. faecalis isolates were resistant to QD, while 4 of 62 (6.5%) E. faecium isolates were resistant to QD. All E. faecalis isolates were susceptible to tigecycline, while 14.5% (9/62) E. faecium isolates were resistant. Continued surveillance of GRE antibiotic susceptibilities is important for combating these multi-resistant nosocomial pathogens. PMID:25566405

  3. Evaluation of BBL CHROMagar VanRE for detection of vancomycin-resistant Enterococci in rectal swab specimens.

    PubMed

    Stamper, Paul D; Shulder, Stephanie; Bekalo, Pearl; Manandhar, Deepika; Ross, Tracy L; Speser, Sharon; Kingery, Julie; Carroll, Karen C

    2010-11-01

    A study was performed on 517 surveillance rectal swabs to evaluate a selective and differential chromogenic medium, the BBL CHROMagar VanRE (CVRE), which enables recovery and identification of VanA- and VanB-containing Enterococcus faecium (ENFM) and Enterococcus faecalis (ENFS) isolates. Compared to BBL Enterococcosel agar, a bile-esculin-azide-vancomycin (BEAV) agar, the initial overall sensitivity, specificity, and positive and negative predictive values of CVRE for the detection of vancomycin-resistant ENFM and ENFS were 99.1% and 94.8% and 84.2% and 99.7%, respectively. Among our patient population, more vancomycin-resistant enterococci (VRE) were recovered with CVRE than BEAV.

  4. Limitations of vitek GPS-418 cards in exact detection of vancomycin-resistant enterococci with the vanB genotype.

    PubMed

    Okabe, T; Oana, K; Kawakami, Y; Yamaguchi, M; Takahashi, Y; Okimura, Y; Honda, T; Katsuyama, T

    2000-06-01

    The susceptibilities of 20 strains of vancomycin-resistant enterococci (VRE) with the vanB genotype obtained by using Vitek GPS-418 cards were compared with those obtained by the broth dilution method of the National Committee for Clinical Laboratory Standards (NCCLS) (approved standard M7-A4) and with those obtained by the agar screen method using bile esculin azide agar containing 6 microgram of vancomycin per ml. Although both the broth dilution and agar screen methods disclosed no discordance, Vitek GPS-418 cards yielded a very major error compared with the results obtained by the reference broth dilution method of the NCCLS. Vitek GPS-418 cards were therefore found to have considerable room for improvement for the accurate detection of vanB VRE strains.

  5. Evaluation of BBL CHROMagar VanRE for Detection of Vancomycin-Resistant Enterococci in Rectal Swab Specimens▿

    PubMed Central

    Stamper, Paul D.; Shulder, Stephanie; Bekalo, Pearl; Manandhar, Deepika; Ross, Tracy L.; Speser, Sharon; Kingery, Julie; Carroll, Karen C.

    2010-01-01

    A study was performed on 517 surveillance rectal swabs to evaluate a selective and differential chromogenic medium, the BBL CHROMagar VanRE (CVRE), which enables recovery and identification of VanA- and VanB-containing Enterococcus faecium (ENFM) and Enterococcus faecalis (ENFS) isolates. Compared to BBL Enterococcosel agar, a bile-esculin-azide-vancomycin (BEAV) agar, the initial overall sensitivity, specificity, and positive and negative predictive values of CVRE for the detection of vancomycin-resistant ENFM and ENFS were 99.1% and 94.8% and 84.2% and 99.7%, respectively. Among our patient population, more vancomycin-resistant enterococci (VRE) were recovered with CVRE than BEAV. PMID:20739492

  6. Perceptual learning of parametric face categories leads to the integration of high-level class-based information but not to high-level pop-out.

    PubMed

    Kietzmann, Tim C; König, Peter

    2010-11-24

    To date, the relative contribution of the different levels of the visual hierarchy during perceptual decisions remains unclear. Typical models of visual processing, with the reverse hierarchy theory (RHT) as a prominent example, strongly emphasize the role of higher levels and interpret lower levels as sequence of simple feature detectors. Here, we investigate this issue based on two analyses. Using a novel combination of perceptual learning based on two classes of parametric faces and a subsequent odd-one-out paradigm, we first test a vital prediction of RHT: high-level pop-out. With this experimental approach, we overcome the low-level confounds of previous studies while still introducing distinct high-level representations. Contrary to previous findings, our analyses show that there is no high-level pop-out, despite very early, near-perfect classification accuracy and extensive training of our subjects. Second, we explore the underlying form of category representation during subsequent stages of perceptual training. This is accomplished by including class-external and class-internal target-distractor combinations. Whereas the subjects' responses during the first sessions are best explained instance-based and dependent on low-level metric differences, later patterns exhibit the inclusion of high-level, class-based information that is independent of target-stimulus similarity. Finally, we show that the utilized level of information is highly task-dependent.

  7. Mechanism of Copper Surface Toxicity in Vancomycin-Resistant Enterococci following Wet or Dry Surface Contact ▿

    PubMed Central

    Warnes, S. L.; Keevil, C. W.

    2011-01-01

    Contaminated touch surfaces have been implicated in the spread of hospital-acquired infections, and the use of biocidal surfaces could help to reduce this cross-contamination. In a previous study we reported the death of aqueous inocula of pathogenic Enterococcus faecalis or Enterococcus faecium isolates, simulating fomite surface contamination, in 1 h on copper alloys, compared to survival for months on stainless steel. In our current study we observed an even faster kill of over a 6-log reduction of viable enterococci in less than 10 min on copper alloys with a “dry” inoculum equivalent to touch contamination. We investigated the effect of copper(I) and copper(II) chelation and the quenching of reactive oxygen species on cell viability assessed by culture and their effects on genomic DNA, membrane potential, and respiration in situ on metal surfaces. We propose that copper surface toxicity for enterococci involves the direct or indirect action of released copper ionic species and the generation of superoxide, resulting in arrested respiration and DNA breakdown as the first stages of cell death. The generation of hydroxyl radicals by the Fenton reaction does not appear to be the dominant instrument of DNA damage. The bacterial membrane potential is unaffected in the early stages of wet and dry surface contact, suggesting that the membrane is not compromised until after cell death. These results also highlight the importance of correct surface cleaning protocols to perpetuate copper ion release and prevent the chelation of ions by contaminants, which could reduce the efficacy of the surface. PMID:21742916

  8. A Silenced vanA Gene Cluster on a Transferable Plasmid Caused an Outbreak of Vancomycin-Variable Enterococci

    PubMed Central

    Sivertsen, Audun; Pedersen, Torunn; Larssen, Kjersti Wik; Bergh, Kåre; Rønning, Torunn Gresdal; Radtke, Andreas

    2016-01-01

    We report an outbreak of vancomycin-variable vanA+ enterococci (VVE) able to escape phenotypic detection by current guidelines and demonstrate the molecular mechanisms for in vivo switching into vancomycin resistance and horizontal spread of the vanA cluster. Forty-eight vanA+ Enterococcus faecium isolates and one Enterococcus faecalis isolate were analyzed for clonality with pulsed-field gel electrophoresis (PFGE), and their vanA gene cluster compositions were assessed by PCR and whole-genome sequencing of six isolates. The susceptible VVE strains were cultivated in brain heart infusion broth containing vancomycin at 8 μg/ml for in vitro development of resistant VVE. The transcription profiles of susceptible VVE and their resistant revertants were assessed using quantitative reverse transcription-PCR. Plasmid content was analyzed with S1 nuclease PFGE and hybridizations. Conjugative transfer of vanA was assessed by filter mating. The only genetic difference between the vanA clusters of susceptible and resistant VVE was an ISL3-family element upstream of vanHAX, which silenced vanHAX gene transcription in susceptible VVE. Furthermore, the VVE had an insertion of IS1542 between orf2 and vanR that attenuated the expression of vanHAX. Growth of susceptible VVE occurred after 24 to 72 h of exposure to vancomycin due to excision of the ISL3-family element. The vanA gene cluster was located on a transferable broad-host-range plasmid also detected in outbreak isolates with different pulsotypes, including one E. faecalis isolate. Horizontally transferable silenced vanA able to escape detection and revert into resistance during vancomycin therapy represents a new challenge in the clinic. Genotypic testing of invasive vancomycin-susceptible enterococci by vanA-PCR is advised. PMID:27139479

  9. Depth-Dependent Survival of Escherichia coli and Enterococci in Soil after Manure Application and Simulated Rainfall

    PubMed Central

    Pachepsky, Y. A.; Hill, R. L.; Shelton, D. R.

    2015-01-01

    Once released, manure-borne bacteria can enter runoff via interaction with the thin mixing layer near the soil surface. The objectives of this work were to document temporal changes in profile distributions of manure-borne Escherichia coli and enterococci in the near-surface soil layers after simulated rainfalls and to examine differences in survival of the two fecal indicator bacteria. Rainfall simulations were performed in triplicate on soil-filled boxes with grass cover and solid manure application for 1 h with rainfall depths of 30, 60, and 90 mm. Soil samples were collected weekly from depth ranges of 0 to 1, 1 to 2, 2 to 5, and 5 to 10 cm for 1 month. Rainfall intensity was found to have a significant impact on the initial concentrations of fecal indicator bacteria in the soil. While total numbers of enterococci rapidly declined over time, E. coli populations experienced initial growth with concentration increases of 4, 10, and 25 times the initial levels at rainfall treatment depths of 30, 60, and 90 mm, respectively. E. coli populations grew to the approximately the same level in all treatments. The 0- to 1-cm layer contained more indicator bacteria than the layers beneath it, and survival of indicator bacteria was better in this layer, with decimation times between 12 and 18 days after the first week of growth. The proportion of bacteria in the 0- to 1-cm layer grew with time as the total number of bacteria in the 0- to 10-cm layer declined. The results of this work indicate the need to revisit the bacterial survival patterns that are assumed in water quality models. PMID:25956764

  10. Ontological Problem-Solving Framework for Assigning Sensor Systems and Algorithms to High-Level Missions

    PubMed Central

    Qualls, Joseph; Russomanno, David J.

    2011-01-01

    The lack of knowledge models to represent sensor systems, algorithms, and missions makes opportunistically discovering a synthesis of systems and algorithms that can satisfy high-level mission specifications impractical. A novel ontological problem-solving framework has been designed that leverages knowledge models describing sensors, algorithms, and high-level missions to facilitate automated inference of assigning systems to subtasks that may satisfy a given mission specification. To demonstrate the efficacy of the ontological problem-solving architecture, a family of persistence surveillance sensor systems and algorithms has been instantiated in a prototype environment to demonstrate the assignment of systems to subtasks of high-level missions. PMID:22164081

  11. Retrieved waste properties and high-level waste critical component ratios for privatization waste feed delivery

    SciTech Connect

    Peters, B.B.

    1998-03-04

    The purpose for this document is to provide the basis for the retrieved waste properties and high-level waste critical component ratios specified in the System Specification for the Double-Shell Tank System.

  12. Evaluation of high-level clouds in cloud resolving model simulations with ARM and KWAJEX observations

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Muhlbauer, Andreas; Ackerman, Thomas

    2015-12-01

    In this study, we evaluate high-level clouds in a cloud resolving model during two convective cases, ARM9707 and KWAJEX. The simulated joint histograms of cloud occurrence and radar reflectivity compare well with cloud radar and satellite observations when using a two-moment microphysics scheme. However, simulations performed with a single moment microphysical scheme exhibit low biases of approximately 20 dB. During convective events, two-moment microphysical overestimate the amount of high-level cloud and one-moment microphysics precipitate too readily and underestimate the amount and height of high-level cloud. For ARM9707, persistent large positive biases in high-level cloud are found, which are not sensitive to changes in ice particle fall velocity and ice nuclei number concentration in the two-moment microphysics. These biases are caused by biases in large-scale forcing and maintained by the periodic lateral boundary conditions. The combined effects include significant biases in high-level cloud amount, radiation, and high sensitivity of cloud amount to nudging time scale in both convective cases. The high sensitivity of high-level cloud amount to the thermodynamic nudging time scale suggests that thermodynamic nudging can be a powerful "tuning" parameter for the simulated cloud and radiation but should be applied with caution. The role of the periodic lateral boundary conditions in reinforcing the biases in cloud and radiation suggests that reducing the uncertainty in the large-scale forcing in high levels is important for similar convective cases and has far reaching implications for simulating high-level clouds in super-parameterized global climate models such as the multiscale modeling framework.

  13. Development of high-level streptomycin resistance affected by a plasmid in lactic streptococci.

    PubMed

    Sinha, R P

    1986-08-01

    Some lactose-negative (Lac-) mutants of Streptococcus lactis C2 and ML3 exhibited development of very high level streptomycin resistance after incubation with subinhibitory concentrations of the drug for 18 to 22 h. These drug-resistant mutants showed no loss of resistance even after 6 months of subculturing in broth without any drug. The parental Lac+ strains did not show mutation to high-level streptomycin resistance. The Lac+ characteristic of the parental strain was conjugally transferred to Lac- derivatives of C2 and ML3, showing the ability to mutate to high-level resistance. When transconjugants were analyzed for this characteristic, they showed both mutable and nonmutable Lac+ types. The results suggested that genetic information for mutation to high-level streptomycin resistance in lactic streptococci resides on the chromosome, and its expression is affected by a plasmid. The plasmid profiles of strains C2, ML3, C2 Lac-, ML3 Lac-, and two kinds of transconjugants confirmed the presence of a plasmid of approximately 5.5 megadaltons in strains showing no mutation to high-level streptomycin resistance, while strains missing such a plasmid exhibited high-level streptomycin resistance after incubation with subinhibitory concentrations of the drug.

  14. [Current aspects of the fecal flora of the newborn without antibiotherapy during the first 7 days of life: Enterobacteriaceae, enterococci, staphylococci].

    PubMed

    Borderon, J C; Lionnet, C; Rondeau, C; Suc, A L; Laugier, J; Gold, F

    1996-05-01

    Last years, il became obvious that the colonization pattern described in 1976-1978 was no more valid: early colonization by Enterobacteriaceae at the 2-3 rd day of life in all newborns, with constant presence of antibioresistant strainseven in non treated newborns. To establish the new pattern of colonization, the same quantitative method of dilution and culture on selective media was used daily from day 1 to day 7 (5 days only for M). The number of Enterobacteriaceae, enterococci and staphylococci was determined in the stools of 10 newborns in the Maternity unit (= M) (term 40 weeks +/- 1, birth weight 3,356 g +/- 383), 10 in the Premature nursery (= P) (term 34.9 weeks +/- 1, birth weight 2,457 g +/- 676), and 14 in the Neonatal intensive care unit (= R) (term 35.2 weeks +/- 3.8, birth weight 2,457 g +/- 763). The results establish that colonization by Enterobacteriaceae is no more constant at D3. It could be demonstrated only in 8/10 M, 1/10 P, and 6/14 R (statistically different - p < 0.01 - between M and P). At D5, 9/10 M, 5/10 P, 10/14 R, and at D7, 6/10 P and 10/14 R were colonized. Resistant Enterobacteriaceae (Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae) could be found in only 3/10 M, 4/10 P and 6/14 R. Enterococci could be found in 1 newborn M, 2 P and 7 newborns R. Staphylococci appeared earlier: all newborns M, P and R were colonized at D2, 4 and 5 respectively. These bacteria were coagulase negative, associated with Staphylococcus aureus in 3 P. Our hypothesis is that late colonization with Enterobacteriaceae and enterococci is due to the improvement of hygiene procedures and due to the decontaminating effect of antibiotics in other treated newborns (Enterobacteriaceae by 3 rd generation cephalosporin and enterococci by pharyngeal vancomycin).

  15. Evaluation of the host-specificity and prevalence of enterococci surface protein (esp) marker in sewage and its application for sourcing human fecal pollution.

    PubMed

    Ahmed, W; Stewart, J; Powell, D; Gardner, T

    2008-01-01

    The suitability of the enterococci surface protein (esp) marker to detect human fecal pollution was evaluated by testing 197 fecal samples from 13 host groups in Southeast Queensland, Australia. Overall, this marker was detected in 90.5% of sewage and septic system samples and could not be detected in any fecal samples from 12 animal host groups. The sensitivity of the esp primer to detect the human-specific esp marker in sewage and septic samples was 100 and 67%, respectively. The overall specificity of this marker to distinguish between human and animal fecal pollution was 100%. Its prevalence in sewage was also determined by testing samples from the raw sewage, secondary effluent, and treated effluent of a sewage treatment plant (STP) over five consecutive days. Of the 15 samples tested, 12 (80%) were found to be positive for this marker. In contrast, it was not found in three samples from the treated effluent and these samples did not contain any culturable enterococci. The PCR limit of detection of this marker in freshwater samples was up to dilution 1 x 10(-4) and the number of culturable enterococci at this dilution was 4.8 x 10(1) +/- 7.0 x 10 degrees colony forming unit (CFU). The utility of this marker was evaluated by testing water samples from three non-sewered catchments in Pine Rivers in Southeast Queensland. Of the 13 samples tested, eight were positive for this marker with the number of enterococci ranging between 1.8 x 10(3) to 8.5 x 10(3) CFU per 100 mL of water. Based on the results, it can be concluded that the esp marker appears to be sewage specific and could be used as a reliable marker to detect human fecal pollution in surface waters in Southeast Queensland, Australia.

  16. Resident Cats in Small Animal Veterinary Hospitals Carry Multi-Drug Resistant Enterococci and are Likely Involved in Cross-Contamination of the Hospital Environment

    PubMed Central

    Ghosh, Anuradha; KuKanich, Kate; Brown, Caitlin E.; Zurek, Ludek

    2012-01-01

    In the USA, small animal veterinary hospitals (SAVHs) commonly keep resident cats living permanently as pets within their facilities. Previously, multi-drug resistant (MDR) enterococci were found as a contaminant of multiple surfaces within such veterinary hospitals, and nosocomial infections are a concern. The objectives of this study were to determine whether resident cats carry MDR enterococci and to compare the feline isolates genotypically to those obtained from SAVH surfaces in a previous study. Enterococcal strains (n = 180) were isolated from the feces of six healthy resident cats from different SAVHs. The concentration of enterococci ranged from 1.1 × 105 to 6.0 × 108 CFU g−1 of feces, and the population comprised Enterococcus hirae (38.3 ± 18.6%), E. faecium (35.0 ± 14.3%), E. faecalis (23.9 ± 11.0%), and E. avium (2.8 ± 2.2%). Testing of phenotypic resistance to 14 antimicrobial agents revealed multi-drug resistance (≥3 antimicrobials) in 48.9% of all enterococcal isolates with most frequent resistance to tetracycline (75.0%), erythromycin (50.0%), and rifampicin (36.1%). Vancomycin resistant E. faecalis (3.9%) with vanB not horizontally transferable in in vitro conjugation assays were detected from one cat. Genotyping with pulsed-field gel electrophoresis demonstrated a host-specific clonal population of MDR E. faecalis and E. faecium. Importantly, several feline isolates were genotypically identical or closely related to isolates from surfaces of cage door, thermometer, and stethoscope of the corresponding SAVHs. These data demonstrate that healthy resident cats at SAVHs carry MDR enterococci and likely contribute to contamination of the SAVH environment. Proper disposal and handling of fecal material and restricted movement of resident cats within the ward are recommended. PMID:22363334

  17. Diversity of Tn1546 and Its Role in the Dissemination of Vancomycin-Resistant Enterococci in Portugal▿

    PubMed Central

    Novais, Carla; Freitas, Ana R.; Sousa, João C.; Baquero, Fernando; Coque, Teresa M.; Peixe, Luísa V.

    2008-01-01

    We characterized the molecular diversity of vanA vancomycin-resistant enterococci (VRE; 176 isolates/87 pulsed-field gel electrophoresis types) from different sources and cities in Portugal (1996 to 2004): (i) food animals (FA; n = 38 isolates out of 31 samples), hospitalized humans (HH; n = 101/101), healthy human volunteers (HV; n = 7/4), and environmental sources (n = 30/10). Some strains were isolated from different hosts and persistently recovered for years. Twenty-four Tn1546 variants were identified, all located on plasmids (30 to 250 kb). Some Tn1546 variants were associated with specific sources such as FA (3 types), HH (11 types), or HV (1 type), while others were recovered from isolates of different origins (8 types). Polymorphisms in the central vanRSHA region of Tn1546 were scarcely detected, while alterations upstream of vanR and downstream of vanA were frequently identified involving mutations (vanS and vanX), deletions (vanY), insertions (IS1216V, ISEf1, and IS19; sequences with or without homology with others available in GenBank databases), and different genetic rearrangements. Most Tn1546 variants contained IS1216V (14 types) or ISEf1 (6 types). IS1216V was found alone or associated with an IS3-like element at different orientations and positions in Tn1546 from human, animal, and environmental samples. ISEf1 was located within vanX-vanY region at nucleotide 9044 of Tn1546 variants mostly associated with clinical isolates, suggesting a common genetic platform. IS19 was observed within the vanX-vanY region in one Tn1546 variant from poultry. Recent spread of VRE in Portugal reflects a complex epidemiology involving both clonal spread and plasmid dissemination containing a variety of Tn1546 types. Apparent Tn1546 heterogeneity among enterococci from human, animal, and environmental sources might reflect frequent genetic exchange events and evolution of particular widely disseminated genetic elements. PMID:18180362

  18. Cloning of the bile salt hydrolase (bsh) gene from Enterococcus faecium FAIR-E 345 and chromosomal location of bsh genes in food enterococci.

    PubMed

    Wijaya, Agus; Hermann, Anette; Abriouel, Hikmate; Specht, Ingrid; Yousif, Nuha M K; Holzapfel, Wilhelm H; Franz, Charles M A P

    2004-12-01

    Enterococcus faecium strain FAIR-E 345 isolated from food was shown to possess bile salt hydrolase (Bsh) activity in a plate screening assay and by high-performance liquid chromatography analysis. The bsh gene was cloned and sequenced. DNA sequence analysis revealed that it encoded a protein of 324 amino acids, with pI 4.877. A bsh gene probe was prepared from the cloned bsh gene and was used for probing plasmid and total genomic DNA of Bsh-positive enterococci isolated from food to determine the genomic location of their bsh genes. This probe was able to detect the bsh gene among total genomic DNA preparations but not from plasmid preparations of 10 plasmid-bearing Enterococcus strains. However, the probe could detect the bsh gene from total genomic DNA preparations of 12 Enterococcus strains that did not contain detectable plasmid DNA. In no cases did the probe hybridize with plasmid DNA preparations, suggesting that the bsh gene among enterococci is probably generally chromosomally encoded. This presumptive chromosomal location of bsh genes among food enterococci suggests that transfer of this trait by conjugative plasmids is unlikely.

  19. Analysis of enterococci using portable testing equipment for developing countries--variance of Azide NutriDisk medium under variable time and temperature.

    PubMed

    Godfrey, S; Watkins, J; Toop, K; Francis, C

    2006-01-01

    This report compares the enterococci count on samples obtained with Azide NutriDisk (AND) (sterile, dehydrated culture medium) and Slanetz and Bartley (SB) medium when exposed to a variable in incubation time and temperature. Three experiments were performed to examine the recovery of enterococci on AND and SB media using membrane filtration with respect to: (a) incubation time; (b) incubation temperature; and (c) a combination of the two. Presumptive counts were observed at 37, 41, 46 and 47 degrees C and at 20, 24, 28 and 48 h. These were compared to AWWA standard method 9230 C (44 degrees C, 44 h). Samples were confirmed using Kanamycin Aesculin Azide (KAA) agar. Friedman's ANOVA and Students t-test analysis indicated higher enumeration of enterococci when grown on AND (p = 0.45) than SB (p = < 0.001) at all temperatures with a survival threshold at 47 degrees C. Significant results for AND medium were noted at 20 h (p = 0.021), 24 h (p = 0.278) and 28 h (p = 0.543). The study concluded that the accuracy of the AND medium at a greater time and temperature range provided flexibility in incubator technology making it an appropriate alternative to SB medium for monitoring drinking water using field testing kits in developing countries.

  20. Exogenous endophthalmitis caused by Enterococcus casseliflavus: A case report and discussion regarding treatment of intraocular infection with vancomycin-resistant enterococci.

    PubMed

    Berenger, Byron M; Kulkarni, Shobhana; Hinz, Brad J; Md, Sarah E Forgie

    2015-01-01

    Endophthalmitis caused by enterococci is rare, and cases involving vancomycin-resistant enterococci are even more so. Due to the poor bioavailability of many antibiotics in the vitreous chamber, special considerations are required when choosing antibiotics to treat these infections. The authors report the first case of exogenous endophthalmitis caused by Enterococcus casseliflavus via the unique mechanism of high-velocity water stream trauma from a toy water gun. A previously healthy four-year old boy presented with endophthalmitis of the left eye after injury from a water gun. Empirical treatment for endophthalmitis was started on presentation to the ophthalmologist. After the identification of the pathogen and a review of the literature, the antibiotic regimen was changed to include intravitreal ampicillin and amikacin with systemic linezolid. Endophthalmitis caused by E casseliflavus and other vancomycin-resistant enterococci are challenging to treat. Rapid identification of vancomycin-resistant enterococcal endophthalmitis is important to guide appropriate antibiotic therapy. Systemic linezolid achieves excellent intravitreal concentrations, and should be used in combination with intravitreal and topical antibiotics.

  1. High-Level Clonal FGFR Amplification and Response to FGFR Inhibition in a Translational Clinical Trial

    PubMed Central

    Babina, Irina S.; Herrera-Abreu, Maria Teresa; Tarazona, Noelia; Peckitt, Clare; Kilgour, Elaine; Smith, Neil R.; Geh, Catherine; Rooney, Claire; Cutts, Ros; Campbell, James; Ning, Jian; Fenwick, Kerry; Swain, Amanda; Brown, Gina; Chua, Sue; Thomas, Anne; Johnston, Stephen R.D.; Ajaz, Mazhar; Sumpter, Katherine; Gillbanks, Angela; Watkins, David; Chau, Ian; Popat, Sanjay; Cunningham, David; Turner, Nicholas C.

    2017-01-01

    FGFR1 and FGFR2 are amplified in many tumor types, yet what determines response to FGFR inhibition in amplified cancers is unknown. In a translational clinical trial, we show that gastric cancers with high-level clonal FGFR2 amplification have a high response rate to the selective FGFR inhibitor AZD4547, whereas cancers with subclonal or low-level amplification did not respond. Using cell lines and patient-derived xenograft models, we show that high-level FGFR2 amplification initiates a distinct oncogene addiction phenotype, characterized by FGFR2-mediated transactivation of alternative receptor kinases, bringing PI3K/mTOR signaling under FGFR control. Signaling in low-level FGFR1-amplified cancers is more restricted to MAPK signaling, limiting sensitivity to FGFR inhibition. Finally, we show that circulating tumor DNA screening can identify high-level clonally amplified cancers. Our data provide a mechanistic understanding of the distinct pattern of oncogene addiction seen in highly amplified cancers and demonstrate the importance of clonality in predicting response to targeted therapy. Significance Robust single-agent response to FGFR inhibition is seen only in high-level FGFR-amplified cancers, with copy-number level dictating response to FGFR inhibition in vitro, in vivo, and in the clinic. High-level amplification of FGFR2 is relatively rare in gastric and breast cancers, and we show that screening for amplification in circulating tumor DNA may present a viable strategy to screen patients. PMID:27179038

  2. The audit of the Replacement High Level Waste Evaporator at the Savannah River Site

    SciTech Connect

    1995-06-26

    The Savannah River Site (Site), owned by the Departmen Energy (Department) and managed by Westinghouse Savannah River Company (Westinghouse), recently changed its primary mission from producing nuclear materials to environmental restoration and waste management. A major focus in the Site`s mission is the storage, treatment, stabilization, and disposal of high level radioactive waste materials. To accomplish this mission, the Site will integrate its high level waste treatment facilities into a High Level Waste System (System), which will process the radioactive waste material in six distinct batches. An integral part of the System is the Replacement High Level Waste Evaporator (Replacement Evaporator) which will evaporate water added to the high level waste during processing, thereby minimizing the volume of the waste stream. Currently, the System has the evaporator and tank farm capacity to accommodate the processing of the first batch of radioactive waste, which is scheduled to begin in March 1996. However, the system will need the Replacement Evaporator to accommodate the volume of water and solvent added during processing of the second batch of radioactive waste scheduled to begin processing in 2004.

  3. Factors related to high-level mobility in male servicemembers with traumatic lower-limb loss.

    PubMed

    Gaunaurd, Ignacio A; Roach, Kathryn E; Raya, Michele A; Hooper, Rebecca; Linberg, Alison A; Laferrier, Justin Z; Campbell, Stuart M; Scoville, Charles; Gailey, Robert S

    2013-01-01

    The purpose of this study was to examine the possible relationship between factors modifiable by rehabilitation interventions (rehabilitation factors), other factors related to lower-limb loss (other factors), and high-level mobility as measured by the Comprehensive High-Level Activity Mobility Predictor (CHAMP) in servicemembers (SMs) with traumatic lower-limb loss. One-hundred eighteen male SMs with either unilateral transtibial amputation (TTA), unilateral transfemoral amputation (TFA), or bilateral lower-limb amputation (BLLA) participated. Stepwise regression analysis was used to develop separate regression models of factors predicting CHAMP score. Regression models containing both rehabilitation factors and other factors explained 81% (TTA), 36% (TFA), and 91% (BLLA) of the variance in CHAMP score. Rehabilitation factors such as lower-limb strength and dynamic balance were found to be significantly related to CHAMP score and can be enhanced with the appropriate intervention. Further, the findings support the importance of salvaging the knee joint and its effect on high-level mobility capabilities. Lastly, the J-shaped energy storage and return feet were found to improve high-level mobility for SMs with TTA. These results could help guide rehabilitation and aid in developing appropriate interventions to assist in maximizing high-level mobility capabilities for SMs with traumatic lower-limb loss.

  4. Extending Automatic Parallelization to Optimize High-Level Abstractions for Multicore

    SciTech Connect

    Liao, C; Quinlan, D J; Willcock, J J; Panas, T

    2008-12-12

    Automatic introduction of OpenMP for sequential applications has attracted significant attention recently because of the proliferation of multicore processors and the simplicity of using OpenMP to express parallelism for shared-memory systems. However, most previous research has only focused on C and Fortran applications operating on primitive data types. C++ applications using high-level abstractions, such as STL containers and complex user-defined types, are largely ignored due to the lack of research compilers that are readily able to recognize high-level object-oriented abstractions and leverage their associated semantics. In this paper, we automatically parallelize C++ applications using ROSE, a multiple-language source-to-source compiler infrastructure which preserves the high-level abstractions and gives us access to their semantics. Several representative parallelization candidate kernels are used to explore semantic-aware parallelization strategies for high-level abstractions, combined with extended compiler analyses. Those kernels include an array-base computation loop, a loop with task-level parallelism, and a domain-specific tree traversal. Our work extends the applicability of automatic parallelization to modern applications using high-level abstractions and exposes more opportunities to take advantage of multicore processors.

  5. PBP 4 Mediates High-Level Resistance to New-Generation Cephalosporins in Staphylococcus aureus

    PubMed Central

    Chan, Liana C.; Gilbert, Aubre; Basuino, Li; da Costa, Thaina M.; Hamilton, Stephanie M.; dos Santos, Katia R.; Chambers, Henry F.

    2016-01-01

    Staphylococcus aureus is an important cause of both hospital- and community-associated methicillin-resistant S. aureus (MRSA) infections worldwide. β-Lactam antibiotics are the drugs of choice to treat S. aureus infections, but resistance to these and other antibiotics make treatment problematic. High-level β-lactam resistance of S. aureus has always been attributed to the horizontally acquired penicillin binding protein 2a (PBP 2a) encoded by the mecA gene. Here, we show that S. aureus can also express high-level resistance to β-lactams, including new-generation broad-spectrum cephalosporins that are active against methicillin-resistant strains, through an uncanonical core genome-encoded penicillin binding protein, PBP 4, a nonessential enzyme previously considered not to be important for staphylococcal β-lactam resistance. Our results show that PBP 4 can mediate high-level resistance to β-lactams. PMID:27067335

  6. Heat transfer analysis of the geologic disposal of spent fuel and high level waste storage canisters

    NASA Astrophysics Data System (ADS)

    Allen, G. K.

    1980-08-01

    Near-field temperatures resulting from the storage of high-level waste canisters and spent unreprocessed fuel assembly canisters in geologic formations were determined. Preliminary design of the repository was modeled for a heat transfer computer code, HEATING5, which used the finite difference method to evaluate transient heat transfer. The heat transfer system was evaluated with several two and three dimensional models which transfer heat by a combination of conduction, natural convention, and radiation. Physical properties of the materials in the model were based upon experimental values for the various geologic formations. The effects of canister spacing, fuel age, and use of an overpack were studied for the analysis of the spent fuel canisters; salt, granite, and basalt were considered as the storage media. The effects of canister diameter and use of an overpack were studied for the analysis of the high-level waste canisters; salt was considered as the only storage media for high-level waste canisters.

  7. High-level waste processing at the Savannah River Site: An update

    SciTech Connect

    Marra, J.E.; Bennett, W.M.; Elder, H.H.; Lee, E.D.; Marra, S.L.; Rutland, P.L.

    1997-09-01

    The Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) in Aiken, SC mg began immobilizing high-level radioactive waste in borosilicate glass in 1996. Currently, the radioactive glass is being produced as a ``sludge-only`` composition by combining washed high-level waste sludge with glass frit. The glass is poured in stainless steel canisters which will eventually be disposed of in a permanent, geological repository. To date, DWPF has produced about 100 canisters of vitrified waste. Future processing operations will, be based on a ``coupled`` feed of washed high-level waste sludge, precipitated cesium, and glass frit. This paper provides an update of the processing activities completed to date, operational/flowsheet problems encountered, and programs underway to increase production rates.

  8. Predictors of High Level of Hostility among Homeless Men on Parole.

    PubMed

    Nyamathi, Adeline; Salem, Benissa; Farabee, David; Hall, Elizabeth; Zhang, Sheldon; Khalilifard, Farinaz; Faucette, Mark; Leake, Barbara

    2014-02-01

    High levels of hostility present a formidable challenge among homeless ex-offenders. This cross-sectional study assessed correlates of high levels of hostility using baseline data collected on recently-released male parolees (N=472; age 18-60) participating in a randomized trial focused on prevention of illicit drug use and recidivism. Predictors of high levels of hostility included greater depressive symptomatology, lower self-esteem, having a mother who was treated for alcohol/drugs, belonging to a gang, more tangible support, having used methamphetamine and having a history of cognitive difficulties. These findings highlight the need to understand predictors of hostility among recently released homeless men and how these predictors may relate to recidivism. Research implications are discussed as these findings will shape future nurse-led harm reduction and community-based interventions.

  9. Determination of total cyanide in Hanford Site high-level wastes

    SciTech Connect

    Winters, W.I.; Pool, K.H.

    1994-05-01

    Nickel ferrocyanide compounds (Na{sub 2-x}Cs{sub x}NiFe (CN){sub 6}) were produced in a scavenging process to remove {sup 137}Cs from Hanford Site single-shell tank waste supernates. Methods for determining total cyanide in Hanford Site high-level wastes are needed for the evaluation of potential exothermic reactions between cyanide and oxidizers such as nitrate and for safe storage, processing, and management of the wastes in compliance with regulatory requirements. Hanford Site laboratory experience in determining cyanide in high-level wastes is summarized. Modifications were made to standard cyanide methods to permit improved handling of high-level waste samples and to eliminate interferences found in Hanford Site waste matrices. Interferences and associated procedure modifications caused by high nitrates/nitrite concentrations, insoluble nickel ferrocyanides, and organic complexants are described.

  10. Enterococci in river Ganga surface waters: Propensity of species distribution, dissemination of antimicrobial-resistance and virulence-markers among species along landscape

    PubMed Central

    2009-01-01

    Background Surface waters quality has declined in developing countries due to rapid industrialization and population growth. The microbiological quality of river Ganga, a life-sustaining surface water resource for large population of northern India, is adversely affected by several point and non-point sources of pollution. Further, untreated surface waters are consumed for drinking and various household tasks in India making the public vulnerable to water-borne diseases and outbreaks. Enterococci, the 'indicator' of water quality, correlates best with the incidence of gastrointestinal diseases as well as prevalence of other pathogenic microorganisms. Therefore, this study aims to determine the distribution of species diversity, dissemination of antimicrobial-resistance and virulence-markers in enterococci with respect to rural-urban landscape along river Ganga in northern India. Results Enterococci density (χ2: 1900, df: 1; p < 0.0001) increased from up-to-down gradient sites in the landscape. Species diversity exhibit significant (χ2: 100.4, df: 20; p < 0.0001) and progressive distribution of E. faecalis, E. faecium, E. durans and E. hirae down the gradient. Statistically discernible (p: 0.0156 – < 0.0001) background pool of resistance and virulence was observed among different Enterococcus spp. recovered from five sites in the up-to-down gradient landscape. A significant correlation was observed in the distribution of multiple-antimicrobial-resistance (viz., erythromycin-rifampicin-gentamicin-methicillin and vancomycin-gentamicin-streptomycin; rs: 0.9747; p: 0.0083) and multiple-virulence-markers (viz., gelE+esp+; rs: 0.9747; p: 0.0083; gelE+efaA+; rs: 0.8944; p: 0.0417) among different Enterococcus spp. Conclusion Our observations show prevalence of multiple-antimicrobial-resistance as well as multiple-virulence traits among different Enterococcus spp. The observed high background pool of resistance and virulence in enterococci in river waters of populous

  11. Is the production of the biogenic amines tyramine and putrescine a species-level trait in enterococci?

    PubMed

    Ladero, Victor; Fernández, María; Calles-Enríquez, Marina; Sánchez-Llana, Esther; Cañedo, Elena; Martín, M Cruz; Alvarez, Miguel A

    2012-05-01

    Biogenic amines (BA) are toxic nitrogenous compounds that can be accumulated in foods via the microbial decarboxylation of certain amino acids. Lactic acid bacteria (LAB) strains belonging to different species and genera have been described as BA producers and are mainly responsible for their synthesis in fermented foods. It is generally accepted that the capacity to produced BAs is strain-dependent. However, the large number of enterococci identified as BA producers suggests that the aminogenic trait may be a species-level characteristic. Enterococcus faecalis, Enterococcus faecium and Enterococcus durans strains of different origin were analysed to determine their capacity to produce tyramine and putrescine. The presence of the genes responsible for this and the identity of their flanking regions were checked by PCR. The results suggest that tyramine biosynthesis is a species-level characteristic in E. faecalis, E. faecium and E. durans. Putrescine synthesis was found to be a species-level trait of E. faecalis, with production occurring via the agmatine deamination pathway. Some E. faecium strains of human origin also produced putrescine; this trait was probably acquired via horizontal gene transfer.

  12. Culture methods impact recovery of antibiotic-resistant Enterococci including Enterococcus cecorum from pre- and postharvest chicken.

    PubMed

    Suyemoto, M M; Barnes, H J; Borst, L B

    2017-03-01

    Pathogenic strains of Enterococcus cecorum (EC) expressing multidrug resistance have emerged. In National Antimicrobial Resistance Monitoring System (NARMS) data, EC is rarely recovered from chickens. Two NARMS methodologies (FDA and USDA) were compared with standard culture (SC) techniques for recovery of EC. NARMS methods failed to detect EC in 58 caecal samples, 20 chicken breast or six whole broiler samples. EC was recovered from 1 of 38 (2·6%) and 2 of 38 (5·2%) preharvest spinal lesions (USDA and FDA method, respectively). In contrast, using the SC method, EC was recovered from 44 of 53 (83%) caecal samples, all 38 (100%) spinal lesions, 14 of 20 (70%) chicken breast samples, and all three spinal lesions identified in whole carcasses. Compared with other Enterococcus spp., EC isolates had a higher prevalence of resistance to macrolides. The NARMS methods significantly affected recovery of enterococcal species other than EC. When the postharvest FDA method was applied to preharvest caecal samples, isolates of Enterococcus faecium were preferentially recovered. All 11 E. faecium isolates were multidrug resistant, including resistance to penicillin, daptomycin and linezolid. These findings confirm that current methodologies may not accurately identify the amount and range of antimicrobial resistance of enterococci from chicken sources.

  13. Effect of subtherapeutic vs. therapeutic administration of macrolides on antimicrobial resistance in Mannheimia haemolytica and enterococci isolated from beef cattle

    PubMed Central

    Zaheer, Rahat; Cook, Shaun R.; Klima, Cassidy L.; Stanford, Kim; Alexander, Trevor; Topp, Edward; Read, Ron R.; McAllister, Tim A.

    2013-01-01

    Macrolides are the first-line treatment against bovine respiratory disease (BRD), and are also used to treat infections in humans. The macrolide, tylosin phosphate, is often included in the diet of cattle as a preventative for liver abscesses in many regions of the world outside of Europe. This study investigated the effects of administering macrolides to beef cattle either systemically through a single subcutaneous injection (therapeutic) or continuously in-feed (subtherapeutic), on the prevalence and antimicrobial resistance of Mannheimia haemolytica and Enterococcus spp. isolated from the nasopharynx and faeces, respectively. Nasopharyngeal and faecal samples were collected weekly over 28 days from untreated beef steers and from steers injected once with tilmicosin or tulathromycin or continuously fed tylosin phosphate at dosages recommended by manufacturers. Tilmicosin and tulathromycin were effective in lowering (P < 0.05) the prevalence of M. haemolytica, whereas subtherapeutic tylosin had no effect. M. haemolytica isolated from control- and macrolide-treated animals were susceptible to macrolides as well as to other antibiotics. Major bacteria co-isolated with M. haemolytica from the nasopharynx included Pasteurella multocida, Staphylococcus spp., Acinetobacter spp., Escherichia coli and Bacillus spp. With the exception of M. haemolytica and P. multocida, erythromycin resistance was frequently found in other isolated species. Both methods of macrolide administration increased (P < 0.05) the proportion of erythromycin resistant enterococci within the population, which was comprised almost exclusively of Enterococcus hirae. Injectable macrolides impacted both respiratory and enteric microbes, whereas orally administered macrolides only influenced enteric bacteria. PMID:23750157

  14. Low Vancomycin MICs and Fecal Densities Reduce the Sensitivity of Screening Methods for Vancomycin Resistance in Enterococci

    PubMed Central

    Perry, Peta; Pryce, Todd; Boehm, John; Kay, Ian; Flexman, James; Coombs, Geoffrey W.; Ingram, Paul R.

    2014-01-01

    Active surveillance is part of a multifaceted approach used to prevent the spread of vancomycin-resistant enterococci (VRE). The impact of fecal density, the vancomycin MIC of the isolate, and the vancomycin concentration in liquid medium on test performance are uncertain. Using fecal specimens spiked with a collection of 18 VRE (predominantly vanB) with a wide vancomycin MIC range, we compared the performances of commercial chromogenic agars (CHROMagar VRE, chromID VRE, Brilliance VRE, and VRE Select) and 1 liquid medium (Enterococcosel enrichment broth) for VRE detection. The specificity of solid media was excellent; however, the sensitivity at 48 h varied from 78 to 94%. Screening using liquid medium was less sensitive than screening with solid media, particularly as the vancomycin content increased. Sensitivity declined (i) as the fecal VRE density decreased, (ii) when the media were assessed at 24 h (versus 48 h), and (iii) for isolates with a low vancomycin MIC (sensitivity, 25 to 75% versus 100% for isolates with vancomycin MIC of <16 mg/liter versus >32 mg/liter on solid medium using 106 CFU/ml of feces). Depending on local epidemiology and in particular VRE vancomycin MICs, the sensitivity of culture-based methods for VRE screening of stool or rectal specimens may be suboptimal, potentially facilitating secondary transmission. PMID:24871216

  15. Changes in antimicrobial resistance among faecal enterococci isolated from growing broilers prophylactically medicated with three commercial antimicrobials.

    PubMed

    Costa, Paulo Martins da; Bica, Alexandra; Vaz-Pires, Paulo; Bernardo, Fernando

    2010-01-01

    A controlled environment poultry house (1600m(2)) was divided into two separated compartments. Three hundred twenty chick containers (each containing 100 chicks) were randomly allocated to each compartment. Antimicrobial products were provided (via drinking water) to one broiler group in three different growth phases for prophylactic purposes: lincomycin associated with spectinomycin from day 1 to day 3, trimethoprim associated with sulfamethoxazole from day 19 to day 21, and tylosin from day 26 to day 28. Feed and faecal samples from both groups were obtained on days 0, 4, 9, 14, 18, 22, 25, 29 and 33. One sample of the drinking water and samples from the broiler house environment were obtained one day before bird placement. A maximum of 16 enterococci isolated from Kanamycin Aesculin Azide Agar were tested for resistance using the disk diffusion method. A high prevalence of resistance to drugs such as tetracycline, erythromycin and nitrofurantoin was detected in enterococcal isolates from medicated and unmedicated flocks. Resistance occurrence in the non-medicated group revealed a shift in resistance profiles with the gradual change of the initial strains, isolated from the day-old chicks' cloacal swabs, by others displaying a different phenotype. Resistance phenotypes obtained from faecal strains were correlated with those isolated from the farm environment and feeds.

  16. Absence of vancomycin-resistant enterococci among highly ESBL-positive crows (Corvus splendens) foraging on hospital waste in Bangladesh

    PubMed Central

    Hasan, Badrul; Järhult, Josef D.

    2015-01-01

    Background Vancomycin-resistant enterococci (VRE) have emerged as a growing problem in hospitals; however, domesticated animals, poultry, and wild birds are acting as potential reservoirs. There is a knowledge gap in the Epidemiology of VRE from Bangladesh. Methods To study the prevalence of VRE and the mechanisms of resistance implicated among wild birds, 238 fecal samples were collected in 2010 from house crows (Corvus splendens) foraging on hospital waste in Bangladesh. Fecal samples were screened by analyzing color change in broth and screening for vanA and vanB resistant genes by PCR. Results Neither vanA nor vanB genes were detected from the fecal samples. The house crow does not seem to constitute a reservoir for VRE. Conclusion The zero prevalence is an indication that foraging on hospital waste does not constitute a major risk of VRE carriage in house crows and this is the first study to focus on the prevalence of VRE from wild birds in Bangladesh. PMID:26679560

  17. A variable DNA recognition site organization establishes the LiaR-mediated cell envelope stress response of enterococci to daptomycin

    PubMed Central

    Davlieva, Milya; Shi, Yiwen; Leonard, Paul G.; Johnson, Troy A.; Zianni, Michael R.; Arias, Cesar A.; Ladbury, John E.; Shamoo, Yousif

    2015-01-01

    LiaR is a ‘master regulator’ of the cell envelope stress response in enterococci and many other Gram-positive organisms. Mutations to liaR can lead to antibiotic resistance to a variety of antibiotics including the cyclic lipopeptide daptomycin. LiaR is phosphorylated in response to membrane stress to regulate downstream target operons. Using DNA footprinting of the regions upstream of the liaXYZ and liaFSR operons we show that LiaR binds an extended stretch of DNA that extends beyond the proposed canonical consensus sequence suggesting a more complex level of regulatory control of target operons. We go on to determine the biochemical and structural basis for increased resistance to daptomycin by the adaptive mutation to LiaR (D191N) first identified from the pathogen Enterococcus faecalis S613. LiaRD191N increases oligomerization of LiaR to form a constitutively activated tetramer that has high affinity for DNA even in the absence of phosphorylation leading to increased resistance. Crystal structures of the LiaR DNA binding domain complexed to the putative consensus sequence as well as an adjoining secondary sequence show that upon binding, LiaR induces DNA bending that is consistent with increased recruitment of RNA polymerase to the transcription start site and upregulation of target operons. PMID:25897118

  18. Enterococcus ureilyticus sp. nov. and Enterococcus rotai sp. nov., two urease-producing enterococci from the environment.

    PubMed

    Sedláček, Ivo; Holochová, Pavla; Mašlaňová, Ivana; Kosina, Marcel; Spröer, Cathrin; Bryndová, Hana; Vandamme, Peter; Rudolf, Ivo; Hubálek, Zdenek; Švec, Pavel

    2013-02-01

    A set of 25 urease-producing, yellow-pigmented enterococci was isolated from environmental sources. Phenotypic classification divided the isolates into two phena. Both phena were characterized using 16S rRNA gene sequence analysis, DNA base composition, rep-PCR fingerprinting and automated ribotyping. The obtained data distinguished the isolates from all members of the genus Enterococcus with validly published names and placed them in the Enterococcus faecalis species group. DNA-DNA hybridization experiments, pheS and rpoA sequencing and whole-cell protein electrophoresis provided conclusive evidence for the classification of each phenon as a novel species of the genus Enterococcus, for which the names Enterococcus ureilyticus sp. nov. (type strain CCM 4629(T)  = LMG 26676(T)  = CCUG 48799(T)), inhabiting water and plants, and Enterococcus rotai sp. nov. (type strain CCM 4630(T)  = LMG 26678(T)  = CCUG 61593(T)), inhabiting water, insects (mosquitoes) and plants, are proposed.

  19. Vancomycin resistant enterococci in urine cultures: Antibiotic susceptibility trends over a decade at a tertiary hospital in the United Kingdom

    PubMed Central

    Toner, Liam; Papa, Nathan; Aliyu, Sani H.; Dev, Harveer; Al-Hayek, Samih

    2016-01-01

    Purpose Enterococci are a common cause of urinary tract infection and vancomycin-resistant strains are more difficult to treat. The purpose of this surveillance program was to assess the prevalence of and determine the risk factors for vancomycin resistance in adults among urinary isolates of Enterococcus sp. and to detail the antibiotic susceptibility profile, which can be used to guide empirical treatment. Materials and Methods From 2005 to 2014 we retrospectively reviewed 5,528 positive Enterococcus sp. urine cultures recorded in a computerized laboratory results database at a tertiary teaching hospital in Cambridge, United Kingdom. Results Of these cultures, 542 (9.8%) were vancomycin resistant. No longitudinal trend was observed in the proportion of vancomycin-resistant strains over the course of the study. We observed emerging resistance to nitrofurantoin with rates climbing from near zero to 40%. Ampicillin resistance fluctuated between 50% and 90%. Low resistance was observed for linezolid and quinupristin/dalfopristin. Female sex and inpatient status were identified as risk factors for vancomycin resistance. Conclusions The incidence of vancomycin resistance among urinary isolates was stable over the last decade. Although resistance to nitrofurantoin has increased, it still serves as an appropriate first choice in uncomplicated urinary tract infection caused by vancomycin-resistant Enterococcus sp. PMID:26981595

  20. A variable DNA recognition site organization establishes the LiaR-mediated cell envelope stress response of enterococci to daptomycin

    DOE PAGES

    Davlieva, Milya; Shi, Yiwen; Leonard, Paul G.; ...

    2015-04-19

    LiaR is a ‘master regulator’ of the cell envelope stress response in enterococci and many other Gram-positive organisms. Mutations to liaR can lead to antibiotic resistance to a variety of antibiotics including the cyclic lipopeptide daptomycin. LiaR is phosphorylated in response to membrane stress to regulate downstream target operons. Using DNA footprinting of the regions upstream of the liaXYZ and liaFSR operons we show that LiaR binds an extended stretch of DNA that extends beyond the proposed canonical consensus sequence suggesting a more complex level of regulatory control of target operons. We go on to determine the biochemical and structuralmore » basis for increased resistance to daptomycin by the adaptive mutation to LiaR (D191N) first identified from the pathogen Enterococcus faecalis S613. LiaRD191N increases oligomerization of LiaR to form a constitutively activated tetramer that has high affinity for DNA even in the absence of phosphorylation leading to increased resistance. The crystal structures of the LiaR DNA binding domain complexed to the putative consensus sequence as well as an adjoining secondary sequence show that upon binding, LiaR induces DNA bending that is consistent with increased recruitment of RNA polymerase to the transcription start site and upregulation of target operons.« less

  1. A variable DNA recognition site organization establishes the LiaR-mediated cell envelope stress response of enterococci to daptomycin

    SciTech Connect

    Davlieva, Milya; Shi, Yiwen; Leonard, Paul G.; Johnson, Troy A.; Zianni, Michael R.; Arias, Cesar A.; Ladbury, John E.; Shamoo, Yousif

    2015-04-19

    LiaR is a ‘master regulator’ of the cell envelope stress response in enterococci and many other Gram-positive organisms. Mutations to liaR can lead to antibiotic resistance to a variety of antibiotics including the cyclic lipopeptide daptomycin. LiaR is phosphorylated in response to membrane stress to regulate downstream target operons. Using DNA footprinting of the regions upstream of the liaXYZ and liaFSR operons we show that LiaR binds an extended stretch of DNA that extends beyond the proposed canonical consensus sequence suggesting a more complex level of regulatory control of target operons. We go on to determine the biochemical and structural basis for increased resistance to daptomycin by the adaptive mutation to LiaR (D191N) first identified from the pathogen Enterococcus faecalis S613. LiaRD191N increases oligomerization of LiaR to form a constitutively activated tetramer that has high affinity for DNA even in the absence of phosphorylation leading to increased resistance. The crystal structures of the LiaR DNA binding domain complexed to the putative consensus sequence as well as an adjoining secondary sequence show that upon binding, LiaR induces DNA bending that is consistent with increased recruitment of RNA polymerase to the transcription start site and upregulation of target operons.

  2. Adhesion to medical device materials and biofilm formation capability of some species of enterococci in different physiological states.

    PubMed

    Lleo, Mar; Bonato, Barbara; Tafi, Maria Carla; Caburlotto, Greta; Benedetti, Dennis; Canepari, Pietro

    2007-09-01

    Enterococci may survive in adverse environments including the human body where bacteriocins, antibiotics, iron-limitation and immune response represent stressing conditions for bacteria that cause division block. In those conditions, bacteria present in the human body would hardly be in an exponentially growing phase but would mostly be in physiological states such as starvation or the viable but nonculturable (VBNC) state. The possibility that the starved and VBNC bacteria can maintain their ability to adhere to living and inanimate substrates is the first mandatory step for them potentially to cause an infection process. In this study it is shown that starved and stationary enterococcal cells are able to form biofilms on plastic material albeit with reduced efficiency as compared to growing cells. Moreover, although VBNC enterococcal forms are not capable of forming biofilms, Enterococcus faecalis and other enterococcal species of medical interest maintain their ability to synthesize the polymeric matrix for a limited period of time under adverse environmental conditions. The data presented, together with those regarding the maintenance of the division recovery potential already proved in nonculturable bacteria, further support the possibility for the VBNC and other nondividing bacterial forms to have a role as infectious agents and to constitute a risk to human health.

  3. Talc-silicon glass-ceramic waste forms for immobilization of high- level calcined waste

    SciTech Connect

    Vinjamuri, K.

    1993-06-01

    Talc-silicon glass-ceramic waste forms are being evaluated as candidates for immobilization of the high level calcined waste stored onsite at the Idaho Chemical Processing Plant. These glass-ceramic waste forms were prepared by hot isostatically pressing a mixture of simulated nonradioactive high level calcined waste, talc, silicon and aluminum metal additives. The waste forms were characterized for density, chemical durability, and glass and crystalline phase compositions. The results indicate improved density and chemical durability as the silicon content is increased.

  4. The radiation characteristics of the transport packages with vitrified high-level waste

    SciTech Connect

    Bogatov, S. A.; Mitenkova, E. F. Novikov, N. V.

    2015-12-15

    The calculation method of neutron yield in the (α, n) reaction for a homogeneous material of arbitrary composition is represented. It is shown that the use of the ORIGEN 2 code excluding the real elemental composition of vitrified high-level waste leads to significant underestimation of the neutron yield in the (α, n) reaction. For vitrified high-level waste and spent nuclear fuel from VVER, the neutron fluxes are analyzed. The thickness of the protective materials for a transfer cask and a shipping cask with vitrified highlevel waste are estimated.

  5. Impact of transporting defense high-level waste to a geologic repository

    SciTech Connect

    Joy, D.S.; Shappert, L.B.; Boyle, J.W.

    1984-08-01

    This transportation study assumes that defense high-level waste is stored in three locations (the Savannah River, Hanford, and Idaho Falls plants) and may be disposed of in (1) a commercial repository or (2) a defense-only repository, either of which could be located at one of the five candidate sites; also documented is a preliminary analysis of the costs and risks of transporting defense high-level waste from the three storage sites to the five potential candidate repository sites. 17 references, 4 figures, 27 tables.

  6. Tank waste remediation system phase I high-level waste feed processability assessment report

    SciTech Connect

    Lambert, S.L.; Stegen, G.E., Westinghouse Hanford

    1996-08-01

    This report evaluates the effects of feed composition on the Phase I high-level waste immobilization process and interim storage facility requirements for the high-level waste glass.Several different Phase I staging (retrieval, blending, and pretreatment) scenarios were used to generate example feed compositions for glass formulations, testing, and glass sensitivity analysis. Glass models and data form laboratory glass studies were used to estimate achievable waste loading and corresponding glass volumes for various Phase I feeds. Key issues related to feed process ability, feed composition, uncertainty, and immobilization process technology are identified for future consideration in other tank waste disposal program activities.

  7. Performance of different types of hearing protectors undergoing high-level impulse noise.

    PubMed

    Buck, Karl

    2009-01-01

    The paper describes the problems that may occur when hearing protectors, usually designed for industrial noise environments, are used for high-level impulse (weapon) noise. The military impulse noise environment is described, as are the different types of passive and active hearing protectors and the measurement procedures. The different mechanisms that may alter the effectiveness of the hearing protectors as well as their global efficiency when submitted to high-level impulse noise are presented. The paper also discusses how the performance values accessible to the user may be used in different damage risk criteria for continuous and impulse noise.

  8. The radiation characteristics of the transport packages with vitrified high-level waste

    NASA Astrophysics Data System (ADS)

    Bogatov, S. A.; Mitenkova, E. F.; Novikov, N. V.

    2015-12-01

    The calculation method of neutron yield in the (α, n) reaction for a homogeneous material of arbitrary composition is represented. It is shown that the use of the ORIGEN 2 code excluding the real elemental composition of vitrified high-level waste leads to significant underestimation of the neutron yield in the (α, n) reaction. For vitrified high-level waste and spent nuclear fuel from VVER, the neutron fluxes are analyzed. The thickness of the protective materials for a transfer cask and a shipping cask with vitrified highlevel waste are estimated.

  9. Solvent extraction in the treatment of acidic high-level liquid waste : where do we stand?

    SciTech Connect

    Horwitz, E. P.; Schulz, W. W.

    1998-06-18

    During the last 15 years, a number of solvent extraction/recovery processes have been developed for the removal of the transuranic elements, {sup 90}Sr and {sup 137}Cs from acidic high-level liquid waste. These processes are based on the use of a variety of both acidic and neutral extractants. This chapter will present an overview and analysis of the various extractants and flowsheets developed to treat acidic high-level liquid waste streams. The advantages and disadvantages of each extractant along with comparisons of the individual systems are discussed.

  10. Community Acquired Enterococcal Urinary Tract Infections and Antibiotic Resistance Profile in North India

    PubMed Central

    Goel, Varun; Kumar, Dinesh; Kumar, Rajendra; Mathur, Purva; Singh, Sarman

    2016-01-01

    Background: Urinary tract infections (UTIs) remain a major problem both in hospitalized and outdoor patients. Multidrug-resistant enterococci are emerging as a major nosocomial pathogen with increasing frequency. However, the incidence of community-acquired enterococcal infections and species prevalent in India is not thoroughly investigated. Objectives: This study aims to estimate the burden of community-acquired UTIs seen at a tertiary care hospital and to identify the Enterococcus species isolated from these patients. The study also aims to determine the antibiotic susceptibility pattern with reference to high-level aminoglycosides and vancomycin. Materials and Methods: Semi-quantitative cultures from a total of 22,810 urine samples obtained from patients seen at various Outpatient Departments were analyzed. From them 115 nonduplicate isolates of enterococci were obtained as significant pure growth (>105 cfu/ml) and speciated. Antibiotic susceptibility was performed by Kirby–Bauer disc diffusion method. Vancomycin resistance screening was performed by the vancomycin screen agar method recommended by Clinical and Laboratory Standards Institute and confirmed by determination of minimum inhibitory concentration by agar dilution method. Results: Of 115 enterococcal isolates, 61 were identified as Enterococcus faecalis, 42 as Enterococcus faecium, 3 each as Enterococcus dispar, and Enterococcus pseudoavium. High-level gentamicin resistance (HLGR) was higher in E. faecium (47.6%) than E. faecalis (32.7%) and HLSR also showed the same pattern with 47.6% and 27.9% resistance, respectively. Vancomycin resistant enterococci accounted for 11.3% of the isolates, and out of them 53.8% were E. faecium by agar dilution method. Conclusion: High rate of resistance to antibiotics of penicillin group and aminoglycosides was observed in our tertiary care hospital even in community acquired UTIs. Hence, there is an urgent need for more rational and restricted use of antimicrobials

  11. Increasing Prevalence of Aminoglycoside-Resistant Enterococcus faecalis Isolates Due to the aac(6’)-aph(2”) Gene: A Therapeutic Problem in Kermanshah, Iran

    PubMed Central

    Khani, Mitra; Fatollahzade, Mahdie; Pajavand, Hamid; Bakhtiari, Somaye; Abiri, Ramin

    2016-01-01

    Background: Enterococci are important pathogens in nosocomial infections. Various types of antibiotics, such as aminoglycosides, are used for treatment of these infections. Enterococci can acquire resistant traits, which can lead to therapeutic problems with aminoglycosides. Objectives: This study was designed to identify the prevalence of, and to compare, the aac(6’)-aph(2”) and aph(3)-IIIa genes and their antimicrobial resistance patterns among Enterococcus faecalis and E. faecium isolates from patients at Imam Reza hospital in Kermanshah in 2011 - 2012. Patients and Methods: One hundred thirty-eight clinical specimens collected from different wards of Imam Reza hospital were identified to the species level by biochemical tests. Antimicrobial susceptibility tests against kanamycin, teicoplanin, streptomycin, imipenem, ciprofloxacin, and ampicillin were performed by the disk diffusion method. The minimum inhibitory concentrations of gentamicin, streptomycin, kanamycin, and amikacin were evaluated with the microbroth dilution method. The aminoglycoside resistance genes aac(6’)-aph(2”) and aph(3”)-IIIa were analyzed with multiplex PCR. Results: The prevalence of isolates was 33 (24.1%) for E. faecium and 63 (46%) for E. faecalis. Eighty-nine percent of the isolates were high-level gentamicin resistant (HLGR), and 32.8% of E. faecium isolates and 67.2% of E. faecalis isolates carried aac(6’)-aph(2”). The prevalence of aph(3”)-IIIa among the E. faecalis and E. faecium isolates was 22.7% and 77.3%, respectively. Conclusions: Remarkably increased incidence of aac(6’)-aph(2”) among HLGR isolates explains the relationship between this gene and the high level of resistance to aminoglycosides. As the resistant gene among enterococci can be transferred, the use of new-generation antibiotics is necessary. PMID:27217920

  12. A HIGH-LEVEL CALCULATION OF THE PROTON AFFINITY OF DIBORANE

    EPA Science Inventory

    The experimental proton affinity of diborane (B2H6) is based on an unstable species, B2H,+, 4 which has been observed only at low temperatures. The present work calculates the proton 5 affinity of diborane using the Gaussian-3 method and other high-level compound ab initio 6 met...

  13. Experiential Learning and Its Role in Training and Improved Practice in High Level Sports Officiating

    ERIC Educational Resources Information Center

    Grover, Kenda S.

    2014-01-01

    This qualitative study investigated how high level sports officials engage in experiential learning to improve their practice. Adult learning occurs in formal, nonformal and informal environments, and in some cases it is difficult to differentiate between these settings. In the case of cycling officials, learning begins in a nonformal environment…

  14. The Evolution of Power System Planning with High Levels of Variable Renewable Generation

    SciTech Connect

    Katz, Jessica; Milligan, Michael

    2016-09-01

    Greening the Grid provides technical assistance to energy system planners, regulators, and grid operators to overcome challenges associated with integrating variable renewable energy into the grid. This document, part of the Greening the Grid introduces the evolution of power system planning with high levels of variable renewable generation.

  15. A SIMPLE CELLULAR AUTOMATON MODEL FOR HIGH-LEVEL VEGETATION DYNAMICS

    EPA Science Inventory

    We have produced a simple two-dimensional (ground-plan) cellular automata model of vegetation dynamics specifically to investigate high-level community processes. The model is probabilistic, with individual plant behavior determined by physiologically-based rules derived from a w...

  16. Is It Really Possible to Test All Educationally Significant Achievements with High Levels of Reliability?

    ERIC Educational Resources Information Center

    Davis, Andrew

    2015-01-01

    PISA claims that it can extend its reach from its current core subjects of Reading, Science, Maths and problem-solving. Yet given the requirement for high levels of reliability for PISA, especially in the light of its current high stakes character, proposed widening of its subject coverage cannot embrace some important aspects of the social and…

  17. Student Motivations as Predictors of High-Level Cognitions in Project-Based Classrooms

    ERIC Educational Resources Information Center

    Stolk, Jonathan; Harari, Janie

    2014-01-01

    It is well established that active learning helps students engage in high-level thinking strategies and develop improved cognitive skills. Motivation and self-regulated learning research, however, illustrates that cognitive engagement is an effortful process that is related to students' valuing of the learning tasks, adoption of internalized goal…

  18. Antecedent and Concurrent Psychosocial Skills That Support High Levels of Achievement within Talent Domains

    ERIC Educational Resources Information Center

    Olszewski-Kubilius, Paula; Subotnik, Rena F.; Worrell, Frank C.

    2015-01-01

    Motivation and emotional regulation are important for the sustained focused study and practice required for high levels of achievement and creative productivity in adulthood. Using the talent development model proposed by the authors as a framework, the authors discuss several important psychosocial skills based on the psychological research…

  19. A Systematic Review of Research on Questioning as a High-Level Cognitive Strategy

    ERIC Educational Resources Information Center

    Davoudi, Mohammad; Sadeghi, Narges Amel

    2015-01-01

    Given the significance of questioning as a high-level cognitive strategy in language teaching and learning in the literature on TEFL as well as in education in general, this study sought to make a systematic review of research studies conducted in the span of the last three decades on the issue of questioning across different disciplines with a…

  20. HTML::GMap-A High Level Perl Wrapper Around the Google Maps(TM) API

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have developed HTML::GMap, a generic, high-level Perl wrapper, to easily build web-based geographic map displays on top of the Google MapsTM Mapping Service. Using HTML::GMap, we built custom display tools to present the molecular diversity data generated by the National Science Foundation-suppor...

  1. Coping with naturally high levels of soil salinity and boron in the westside of central California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Westside of central California, over 200,000 ha exhibit naturally high levels of salinity and boron (B). The Coast Ranges of the west central California evolved from complex folding and faulting of sedimentary and igneous rocks of Mesozoic and Tertiary age. Cretaceous and Tertiary marine sedi...

  2. Driving Objectives and High-level Requirements for KP-Lab Technologies

    ERIC Educational Resources Information Center

    Lakkala, Minna; Paavola, Sami; Toikka, Seppo; Bauters, Merja; Markannen, Hannu; de Groot, Reuma; Ben Ami, Zvi; Baurens, Benoit; Jadin, Tanja; Richter, Christoph; Zoserl, Eva; Batatia, Hadj; Paralic, Jan; Babic, Frantisek; Damsa, Crina; Sins, Patrick; Moen, Anne; Norenes, Svein Olav; Bugnon, Alexandra; Karlgren, Klas; Kotzinons, Dimitris

    2008-01-01

    One of the central goals of the KP-Lab project is to co-design pedagogical methods and technologies for knowledge creation and practice transformation in an integrative and reciprocal manner. In order to facilitate this process user tasks, driving objectives and high-level requirements have been introduced as conceptual tools to mediate between…

  3. Effects of Crowding and Attention on High-Levels of Motion Processing and Motion Adaptation

    PubMed Central

    Pavan, Andrea; Greenlee, Mark W.

    2015-01-01

    The motion after-effect (MAE) persists in crowding conditions, i.e., when the adaptation direction cannot be reliably perceived. The MAE originating from complex moving patterns spreads into non-adapted sectors of a multi-sector adapting display (i.e., phantom MAE). In the present study we used global rotating patterns to measure the strength of the conventional and phantom MAEs in crowded and non-crowded conditions, and when attention was directed to the adapting stimulus and when it was diverted away from the adapting stimulus. The results show that: (i) the phantom MAE is weaker than the conventional MAE, for both non-crowded and crowded conditions, and when attention was focused on the adapting stimulus and when it was diverted from it, (ii) conventional and phantom MAEs in the crowded condition are weaker than in the non-crowded condition. Analysis conducted to assess the effect of crowding on high-level of motion adaptation suggests that crowding is likely to affect the awareness of the adapting stimulus rather than degrading its sensory representation, (iii) for high-level of motion processing the attentional manipulation does not affect the strength of either conventional or phantom MAEs, neither in the non-crowded nor in the crowded conditions. These results suggest that high-level MAEs do not depend on attention and that at high-level of motion adaptation the effects of crowding are not modulated by attention. PMID:25615577

  4. High Level Manpower and Technological Change in the Steel Industry: Implications for Corporate Manpower Planning.

    ERIC Educational Resources Information Center

    Hiestand, Dale L.

    The purpose of this study was to examine the role that high level manpower plays in the establishment of new technologies at the plant and industry level. The steel industry was selected as an appropriate industry to approach these questions due to: its considerable technological changes; its straightforward, easier-to-understand technology; its…

  5. A Simple Gauss-Newton Procedure for Covariance Structure Analysis with High-Level Computer Languages.

    ERIC Educational Resources Information Center

    Cudeck, Robert; And Others

    1993-01-01

    An implementation of the Gauss-Newton algorithm for the analysis of covariance structure that is specifically adapted for high-level computer languages is reviewed. This simple method for estimating structural equation models is useful for a variety of standard models, as is illustrated. (SLD)

  6. The Role of High Level Play as a Predictor Social Functioning in Autism

    ERIC Educational Resources Information Center

    Manning, Margaret M.; Wainwright, Laurel D.

    2010-01-01

    Play and social abilities of a group of children diagnosed with high functioning autism were compared to a second group diagnosed with a variety of developmental language disorders (DLD). The children with autism engaged in fewer acts of high level play. The children with autism also had significantly lower social functioning than the DLD group…

  7. Plastid-expressed 5-enolpyruvylshikimate-3-phosphate synthase genes provide high level glyphosate tolerance in tobacco.

    PubMed

    Ye, G N; Hajdukiewicz, P T; Broyles, D; Rodriguez, D; Xu, C W; Nehra, N; Staub, J M

    2001-02-01

    Plastid transformation (transplastomic) technology has several potential advantages for biotechnological applications including the use of unmodified prokaryotic genes for engineering, potential high-level gene expression and gene containment due to maternal inheritance in most crop plants. However, the efficacy of a plastid-encoded trait may change depending on plastid number and tissue type. We report a feasibility study in tobacco plastids to achieve high-level herbicide resistance in both vegetative tissues and reproductive organs. We chose to test glyphosate resistance via over-expression in plastids of tolerant forms of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Immunological, enzymatic and whole-plant assays were used to prove the efficacy of three different prokaryotic (Achromobacter, Agrobacterium and Bacillus) EPSPS genes. Using the Agrobacterium strain CP4 EPSPS as a model we identified translational control sequences that direct a 10,000-fold range of protein accumulation (to >10% total soluble protein in leaves). Plastid-expressed EPSPS could provide very high levels of glyphosate resistance, although levels of resistance in vegetative and reproductive tissues differed depending on EPSPS accumulation levels, and correlated to the plastid abundance in these tissues. Paradoxically, higher levels of plastid-expressed EPSPS protein accumulation were apparently required for efficacy than from a similar nuclear-encoded gene. Nevertheless, the demonstration of high-level glyphosate tolerance in vegetative and reproductive organs using transplastomic technology provides a necessary step for transfer of this technology to other crop species.

  8. Structural integrity and potential failure modes of hanford high-level waste tanks

    SciTech Connect

    Han, F.C.

    1996-09-30

    Structural Integrity of the Hanford High-Level Waste Tanks were evaluated based on the existing Design and Analysis Documents. All tank structures were found adequate for the normal operating and seismic loads. Potential failure modes of the tanks were assessed by engineering interpretation and extrapolation of the existing engineering documents.

  9. Chemical evolution of a high-level magma system: the Black Mountain volcanic center, southern Nevada

    SciTech Connect

    Vogel, T.A.; Noble, D.C.; Younker, L.W.

    1983-09-01

    A comprehensive study of stratigraphically controlled samples of both lavas and ash-flow tuffs from the Black Mountain volcanic center enables us to evaluate magmatic processes. The results of this study are used to: (1) determine how this high-level magma system developed; (2) compare this system with other similar systems; and (3) correlate ash-flow sheets using their chemical characteristics.

  10. Interaction Networks: Generating High Level Hints Based on Network Community Clustering

    ERIC Educational Resources Information Center

    Eagle, Michael; Johnson, Matthew; Barnes, Tiffany

    2012-01-01

    We introduce a novel data structure, the Interaction Network, for representing interaction-data from open problem solving environment tutors. We show how using network community detecting techniques are used to identify sub-goals in problems in a logic tutor. We then use those community structures to generate high level hints between sub-goals.…

  11. High-level waste-form-product performance evaluation. [Leaching; waste loading; mechanical stability

    SciTech Connect

    Bernadzikowski, T A; Allender, J S; Stone, J A; Gordon, D E; Gould, Jr, T H; Westberry, III, C F

    1982-01-01

    Seven candidate waste forms were evaluated for immobilization and geologic disposal of high-level radioactive wastes. The waste forms were compared on the basis of leach resistance, mechanical stability, and waste loading. All forms performed well at leaching temperatures of 40, 90, and 150/sup 0/C. Ceramic forms ranked highest, followed by glasses, a metal matrix form, and concrete. 11 tables.

  12. 75 FR 61228 - Board Meeting: Technical Lessons Gained From High-Level Nuclear Waste Disposal Efforts

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-04

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR WASTE TECHNICAL REVIEW BOARD Board Meeting: Technical Lessons Gained From High-Level Nuclear Waste Disposal Efforts Pursuant to its authority under section 5051 of Public Law 100-203, Nuclear Waste Policy Amendments Act...

  13. Conceptual design report for immobilized high-level waste interim storage facility (Phase 1)

    SciTech Connect

    Burgard, K.C.

    1998-06-02

    The Hanford Site Canister Storage Building (CSB Bldg. 212H) will be utilized to interim store Phase 1 HLW products. Project W-464, Immobilized High-Level Waste Interim Storage, will procure an onsite transportation system and retrofit the CSB to accommodate the Phase 1 HLW products. The Conceptual Design Report establishes the Project W-464 technical and cost basis.

  14. Semantic-Aware Automatic Parallelization of Modern Applications Using High-Level Abstractions

    SciTech Connect

    Liao, C; Quinlan, D J; Willcock, J J; Panas, T

    2009-12-21

    Automatic introduction of OpenMP for sequential applications has attracted significant attention recently because of the proliferation of multicore processors and the simplicity of using OpenMP to express parallelism for shared-memory systems. However, most previous research has only focused on C and Fortran applications operating on primitive data types. Modern applications using high-level abstractions, such as C++ STL containers and complex user-defined class types, are largely ignored due to the lack of research compilers that are readily able to recognize high-level object-oriented abstractions and leverage their associated semantics. In this paper, we use a source-to-source compiler infrastructure, ROSE, to explore compiler techniques to recognize high-level abstractions and to exploit their semantics for automatic parallelization. Several representative parallelization candidate kernels are used to study semantic-aware parallelization strategies for high-level abstractions, combined with extended compiler analyses. Preliminary results have shown that semantics of abstractions can help extend the applicability of automatic parallelization to modern applications and expose more opportunities to take advantage of multicore processors.

  15. Advanced Inverter Functions to Support High Levels of Distributed Solar: Policy and Regulatory Considerations (Brochure)

    SciTech Connect

    Not Available

    2014-11-01

    This paper explains how advanced inverter functions (sometimes called 'smart inverters') contribute to the integration of high levels of solar PV generation onto the electrical grid and covers the contributions of advanced functions to maintaining grid stability. Policy and regulatory considerations associated with the deployment of advanced inverter functions are also introduced.

  16. Using High Level Upperclass Undergraduates as TAs in Large Lower Division EFL Classes

    ERIC Educational Resources Information Center

    Shi, Yeli

    2010-01-01

    The purpose of this paper is to offer a feasible way to show that the problem of large EFL courses for lower division can be solved by the use of high level upperclass undergraduates as teaching assistants in and out of class. The use of UTAs fragments the large class into seemingly small classes with view to stimulating interest and effective…

  17. 77 FR 1778 - U.S.-EU High Level Working Group on Jobs and Growth

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-11

    ... TRADE REPRESENTATIVE U.S.-EU High Level Working Group on Jobs and Growth AGENCY: Office of the United... Working Group on Jobs and Growth, led by U.S. Trade Representative Ron Kirk and EU Trade Commissioner... and investment to support mutually beneficial job creation, economic growth, and...

  18. Multilocus Phylogenetics Show High Levels of Endemic Fusaria Inhabiting Sardinian Soils (Tyrrhenian Islands)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Mediterranean island of Sardinia is well known for high levels of vascular plant diversity and endemism, but little is known about its microbial diversity. Under the hypothesis that Fusarium species would show similar patterns, we estimated variability in Fusarium species composition among ten ...

  19. Design of equipment used for high-level waste vitrification at the West Valley Demonstration Project

    SciTech Connect

    Vance, R.F.; Brill, B.A.; Carl, D.E.

    1997-06-01

    The equipment as designed, started, and operated for high-level radioactive waste vitrification at the West Valley Demonstration Project in western New York State is described. Equipment for the processes of melter feed make-up, vitrification, canister handling, and off-gas treatment are included. For each item of equipment the functional requirements, process description, and hardware descriptions are presented.

  20. Insect cell transformation vectors that support high level expression and promoter assessment in insect cell culture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A somatic transformation vector, pDP9, was constructed that provides a simplified means of producing permanently transformed cultured insect cells that support high levels of protein expression of foreign genes. The pDP9 plasmid vector incorporates DNA sequences from the Junonia coenia densovirus th...

  1. Chem I Supplement. Chemistry Related to Isolation of High-Level Nuclear Waste.

    ERIC Educational Resources Information Center

    Hoffman, Darleane C.; Choppin, Gregory R.

    1986-01-01

    Discusses some of the problems associated with the safe disposal of high-level nuclear wastes. Describes several waste disposal plans developed by various nations. Outlines the multiple-barrier concept of isolation in deep geological questions associated with the implementation of such a method. (TW)

  2. Conceptual design report for immobilized high-level waste interim storage facility (Phase 1)

    SciTech Connect

    Burgard, K.C.

    1998-04-09

    The Hanford Site Canister Storage Building (CSB Bldg. 212H) will be utilized to interim store Phase 1 HLW products. Project W-464, Immobilized High-Level Waste Interim Storage, will procure an onsite transportation system and retrofit the CSB to accommodate the Phase 1 HLW products. The Conceptual Design Report establishes the Project W-464 technical and cost basis.

  3. Optimization of waste loading in high-level glass in the presence of uncertainty

    SciTech Connect

    Hoza, M.; Fann, G.I.; Hopkins, D.F.

    1995-02-01

    Hanford high-level liquid waste will be converted into a glass form for long-term storage. The glass must meet certain constraints on its composition and properties in order to have desired properties for processing (e.g., electrical conductivity, viscosity, and liquidus temperature) and acceptable durability for long-term storage. The Optimal Waste Loading (OWL) models, based on rigorous mathematical optimization techniques, have been developed to minimize the number of glass logs required and determine glass-former compositions that will produce a glass meeting all relevant constraints. There is considerable uncertainty in many of the models and data relevant to the formulation of high-level glass. In this paper, we discuss how we handle uncertainty in the glass property models and in the high-level waste composition to the vitrification process. Glass property constraints used in optimization are inequalities that relate glass property models obtained by regression analysis of experimental data to numerical limits on property values. Therefore, these constraints are subject to uncertainty. The sampling distributions of the regression models are used to describe the uncertainties associated with the constraints. The optimization then accounts for these uncertainties by requiring the constraints to be satisfied within specified confidence limits. The uncertainty in waste composition is handled using stochastic optimization. Given means and standard deviations of component masses in the high-level waste stream, distributions of possible values for each component are generated. A series of optimization runs is performed; the distribution of each waste component is sampled for each run. The resultant distribution of solutions is then statistically summarized. The ability of OWL models to handle these forms of uncertainty make them very useful tools in designing and evaluating high-level waste glasses formulations.

  4. Lead-iron phosphate glass as a containment medium for the disposal of high-level nuclear wastes

    DOEpatents

    Boatner, L.A.; Sales, B.C.

    1984-04-11

    Disclosed are lead-iron phosphate glasses containing a high level of Fe/sub 2/O/sub 3/ for use as a storage medium for high-level radioactive nuclear waste. By combining lead-iron phosphate glass with various types of simulated high-level nuclear waste

  5. Identification of Enterococcus faecium and Enterococcus faecalis as vanC-type Vancomycin-Resistant Enterococci (VRE) from sewage and river water in the provincial city of Miyazaki, Japan.

    PubMed

    Nishiyama, Masateru; Iguchi, Atsushi; Suzuki, Yoshihiro

    2015-01-01

    As a first step for assessing the risk to human health posed by vancomycin-resistant enterococci (VRE) in the aquatic environment, we screened sewage and urban river water samples from Miyazaki, Japan for VRE. Because vancomycin-resistant organisms are not as prevalent in sewage and river water as vancomycin-susceptible organisms, the samples were screened by minimum inhibitory concentration test using the vancomycin-supplemented membrane-Enterococcus indoxyl-β-d-glucoside (mEI) agar. The isolates, presumed to be enterococci, were identified using 16S rRNA sequencing analysis. The percentages of VRE isolates screened using 4 μg mL(-1) vancomycin-supplemented mEI agar from sewage and urban river water samples were 12% and 24%, respectively. The vancomycin-resistant genes vanC1 and vanC2/3 were detected in the isolates from both samples by PCR analysis. All enterococci isolates containing vanC1, which is a specific gene for vanC-type of VRE, were identified as Enterococcus casseliflavus/gallinarum. Further, 92% enterococci isolates containing vanC2/3 were identified as E. casseliflavus/gallinarum, the remaining isolates containing vanC2/3 were E. faecium (4%) and E. faecalis (4%). Thereafter, the distribution of E. faecium and E. faecalis, which are the major types of enterococci in humans containing vanC2/3, was observed in the water samples collected.

  6. Temporal Processing Capacity in High-Level Visual Cortex Is Domain Specific

    PubMed Central

    Weiner, Kevin S.; Grill-Spector, Kalanit

    2015-01-01

    Prevailing hierarchical models propose that temporal processing capacity—the amount of information that a brain region processes in a unit time—decreases at higher stages in the ventral stream regardless of domain. However, it is unknown if temporal processing capacities are domain general or domain specific in human high-level visual cortex. Using a novel fMRI paradigm, we measured temporal capacities of functional regions in high-level visual cortex. Contrary to hierarchical models, our data reveal domain-specific processing capacities as follows: (1) regions processing information from different domains have differential temporal capacities within each stage of the visual hierarchy and (2) domain-specific regions display the same temporal capacity regardless of their position in the processing hierarchy. In general, character-selective regions have the lowest capacity, face- and place-selective regions have an intermediate capacity, and body-selective regions have the highest capacity. Notably, domain-specific temporal processing capacities are not apparent in V1 and have perceptual implications. Behavioral testing revealed that the encoding capacity of body images is higher than that of characters, faces, and places, and there is a correspondence between peak encoding rates and cortical capacities for characters and bodies. The present evidence supports a model in which the natural statistics of temporal information in the visual world may affect domain-specific temporal processing and encoding capacities. These findings suggest that the functional organization of high-level visual cortex may be constrained by temporal characteristics of stimuli in the natural world, and this temporal capacity is a characteristic of domain-specific networks in high-level visual cortex. SIGNIFICANCE STATEMENT Visual stimuli bombard us at different rates every day. For example, words and scenes are typically stationary and vary at slow rates. In contrast, bodies are dynamic

  7. Temporal Processing Capacity in High-Level Visual Cortex Is Domain Specific.

    PubMed

    Stigliani, Anthony; Weiner, Kevin S; Grill-Spector, Kalanit

    2015-09-09

    Prevailing hierarchical models propose that temporal processing capacity--the amount of information that a brain region processes in a unit time--decreases at higher stages in the ventral stream regardless of domain. However, it is unknown if temporal processing capacities are domain general or domain specific in human high-level visual cortex. Using a novel fMRI paradigm, we measured temporal capacities of functional regions in high-level visual cortex. Contrary to hierarchical models, our data reveal domain-specific processing capacities as follows: (1) regions processing information from different domains have differential temporal capacities within each stage of the visual hierarchy and (2) domain-specific regions display the same temporal capacity regardless of their position in the processing hierarchy. In general, character-selective regions have the lowest capacity, face- and place-selective regions have an intermediate capacity, and body-selective regions have the highest capacity. Notably, domain-specific temporal processing capacities are not apparent in V1 and have perceptual implications. Behavioral testing revealed that the encoding capacity of body images is higher than that of characters, faces, and places, and there is a correspondence between peak encoding rates and cortical capacities for characters and bodies. The present evidence supports a model in which the natural statistics of temporal information in the visual world may affect domain-specific temporal processing and encoding capacities. These findings suggest that the functional organization of high-level visual cortex may be constrained by temporal characteristics of stimuli in the natural world, and this temporal capacity is a characteristic of domain-specific networks in high-level visual cortex. Significance statement: Visual stimuli bombard us at different rates every day. For example, words and scenes are typically stationary and vary at slow rates. In contrast, bodies are dynamic

  8. Vancomycin-resistant enterococci in intensive-care hospital settings: Transmission dynamics, persistence, and the impact of infection control programs

    PubMed Central

    Austin, Daren J.; Bonten, Marc J. M.; Weinstein, Robert A.; Slaughter, Sarah; Anderson, Roy M.

    1999-01-01

    Vancomycin-resistant enterococci (VRE) recently have emerged as a nosocomial pathogen especially in intensive-care units (ICUs) worldwide. Transmission via the hands of health-care workers is an important determinant of spread and persistence in a VRE-endemic ICU. We describe the transmission of nosocomial pathogens by using a micro-epidemiological framework based on the transmission dynamics of vector-borne diseases. By using the concept of a basic reproductive number, R0, defined as the average number of secondary cases generated by one primary case, we show quantitatively how infection control measures such as hand washing, cohorting, and antibiotic restriction affect nosocomial cross-transmission. By using detailed molecular epidemiological surveillance and compliance monitoring, we found that the estimated basic reproductive number for VRE during a study at the Cook County Hospital, Chicago, was approximately 3–4 without infection control and 0.7 when infection control measures were included. The impact of infection control was to reduce the prevalence from a predicted 79% to an observed 36%. Hand washing and staff cohorting are the most powerful control measures although their efficacy depends on the magnitude of R0. Under the circumstances tested, endemicity of VRE was stabilized despite infection control measures, by the constant introduction of colonized patients. Multiple stochastic simulations of the model revealed excellent agreement with observed pattern. In conjunction with detailed microbiological surveillance, a mathematical framework provides a precise template to describe the colonization dynamics of VRE in ICUs and impact of infection control measures. Our analyses suggest that compliance for hand washing significantly in excess of reported levels, or the cohorting of nursing staff, are needed to prevent nosocomial transmission of VRE in endemic settings. PMID:10359812

  9. Observations and modeling of enterococci release and transport in the inter-tidal zone of a subtropical recreational beach

    NASA Astrophysics Data System (ADS)

    Feng, Z.; Reniers, A. J.

    2010-12-01

    Data from an intensive 10-day field effort of hourly sampled enterococci (ENT) concentrations in the inter-tidal zone of subtropical Hobie Beach (Miami) showed large variability (by three orders of magnitude) in ENT levels, both in the water and the sand, on any given day. The ENT to the site comes from non-point sources (not related to an outfall). Spectral analysis of observed log-scale ENT levels reveal two predominant peaks centered at 1.03 and 1.98 cycles per day (CPD), which are close to diurnal cycle of solar radiation and semidiurnal cycle of local tides (M2), respectively. In addition significant variation is found in ENT levels at other time scales, which may be related to other factors, such as rainfall, runoff and ground water flow, stirring of sediment by waves, inherent spatial variability of ENT in the sand, as well as human and animal shedding. To get a better understanding of how these environmental factors and hydrodynamic conditions affect the ENT variations at a non-point source beach, the release and transport of ENT in the inter-tidal zone was simulated with a numerical model. To that end, XBeach, a coastal morphodynamic model, was extended with the physical processes of wave-induced release of ENT from sand, the entrainment of ENT by ground water flow and biological inactivation by solar radiation. Model-data comparisons for the 10-day sampling period were used to discriminate between the different processes responsible for the uptake and transport of ENT in the inter-tidal zone.

  10. Fosfomycin Enhances the Activity of Daptomycin against Vancomycin-Resistant Enterococci in an In Vitro Pharmacokinetic-Pharmacodynamic Model

    PubMed Central

    Hall Snyder, Ashley D.; Werth, Brian J.; Nonejuie, Poochit; McRoberts, John P.; Pogliano, Joe; Sakoulas, George; Yim, Juwon; Singh, Nivedita

    2016-01-01

    Daptomycin (DAP) is being used more frequently to treat infections caused by vancomycin-resistant enterococcus (VRE). DAP tends to be less active against enterococci than staphylococci and may require high doses or combination therapy to be bactericidal. Fosfomycin (FOF) has activity against VRE and has demonstrated synergistic bactericidal activity with DAP in vitro. The objective of this study was to evaluate the activity of DAP alone and in combination with FOF against VRE in an in vitro pharmacokinetic/pharmacodynamic (PK/PD) model. The activity of DAP at 8 and 12 mg/kg of body weight/day (DAP 8 and DAP 12, respectively) and FOF of 40 mg/kg intravenously every 8 h, alone and in combination, were evaluated against 2 vancomycin-resistant Enterococcus faecium strains (8019 and 5938) and 2 vancomycin-resistant E. faecalis strains (V583 and R7302) in an in vitro PK/PD model over 72 h. Cell surface charge in the presence and absence of FOF was evaluated by zeta potential analysis. Daptomycin-boron-dipyrromethene (bodipy) binding was assessed by fluorescence microscopy. The addition of FOF to DAP 8 and DAP 12 resulted in significantly increased killing over DAP alone at 72 h for 8019, V583, and R7302 (P < 0.05). Therapeutic enhancement was observed with DAP 12 plus FOF against 8019, V583, and R7302. Cell surface charge became more negative after exposure to FOF by ∼2 to 8mV in all 4 strains. Daptomycin-bodipy binding increased by 2.6 times in the presence of fosfomycin (P < 0.0001). The combination of DAP plus FOF may provide improved killing against VRE (including DAP-resistant strains) through modulation of cell surface charge. Further studies to clarify the role of intravenous FOF are warranted. PMID:27431211

  11. Detection and characterization of vancomycin-resistant enterococci in farm animals and raw meat products in Italy.

    PubMed

    Del Grosso, M; Caprioli, A; Chinzari, P; Fontana, M C; Pezzotti, G; Manfrin, A; Giannatale, E D; Goffredo, E; Pantosti, A

    2000-01-01

    The emergence of vancomycin-resistant enterococci (VRE) in Europe has been ascribed to the long-time use of the glycopeptide antibiotic avoparcin as feed additive in food animals, until its ban in 1997 in EU. The pres- ence of VRE in food of animal origin is believed to represent a potential risk for the consumer. We studied the fecal carriage of VRE in broiler chickens and slaughter pigs in Italy before the avoparcin ban and eval- uated the impact of avoparcin withdrawal on the presence of VRE in raw meat products. Broilers and pigs were both found to be frequently colonized by VRE, as 36% and 24.6% of the flocks or the herds, respec- tively, were positive. Molecular typing of VRE strains by PFGE showed that animals housed in different pens within the same farm were colonized by clonally related strains. After the avoparcin ban, a decrease in the rate of VRE contamination in meat products was observed. Such a decrease was statistically significant in poultry (from 18.8% to 9.6%) but not in pork products (from 9.7% to 6.9%). The majority of VRE from all sources carried the vanA resistance gene and included Enterococcus faecium, E. faecalis, E. hirae, E. durans, and E. gallinarum. None of the strains carried the vanB gene, whereas constitutively resistant vanC-positive strains were frequently found. Our results show that avoparcin withdrawal has been successful in reducing VRE contamination in meat products. However, this measure needs to be complemented by a prudent use of glycopeptide antibiotics in human medicine.

  12. West Valley demonstration project: alternative processes for solidifying the high-level wastes

    SciTech Connect

    Holton, L.K.; Larson, D.E.; Partain, W.L.; Treat, R.L.

    1981-10-01

    In 1980, the US Department of Energy (DOE) established the West Valley Solidification Project as the result of legislation passed by the US Congress. The purpose of this project was to carry out a high level nuclear waste management demonstration project at the Western New York Nuclear Service Center in West Valley, New York. The DOE authorized the Pacific Northwest Laboratory (PNL), which is operated by Battelle Memorial Institute, to assess alternative processes for treatment and solidification of the WNYNSC high-level wastes. The Process Alternatives Study is the suject of this report. Two pretreatment approaches and several waste form processes were selected for evaluation in this study. The two waste treatment approaches were the salt/sludge separation process and the combined waste process. Both terminal and interim waste form processes were studied.

  13. Perspective on demonstrations of compliance for high-level waste disposal

    SciTech Connect

    Kocher, D.C.; Smith, E.D.; O'Kelly, G.D.; Sjoreen, A.L.

    1984-03-15

    This paper discusses a perspective which we have developed on the problem of demonstrating compliance of high-level waste repositories with system performance standards. Our viewpoint arises from two primary concerns - first, that the US Environmental Protection Agency's proposed environmental standard for high-level waste disposal appears to require demonstrations of compliance which are incompatible with scientific knowledge, and, second, that the federal agencies involved in the licensing process may not appreciate fully the extent of unquantifiable and uresolvable uncertainty in repository performance-assessment models. We propose a general approach to demonstrations of compliance which we feel is compatible with the kinds of technical information that will be available for judging repository performance. Our approach emphasizes the importance of investigation alternative conceptual models and lines of reasoning in evaluating repository performance and the importance of subjective scientific judgment in the desision-making process. 24 references, 1 figure.

  14. Human factors programs for high-level radioactive waste handling systems

    SciTech Connect

    Pond, D.J.

    1992-04-01

    Human Factors is the discipline concerned with the acquisition of knowledge about human capabilities and limitations, and the application of such knowledge to the design of systems. This paper discusses the range of human factors issues relevant to high-level radioactive waste (HLRW) management systems and, based on examples from other organizations, presents mechanisms through which to assure application of such expertise in the safe, efficient, and effective management and disposal of high-level waste. Additionally, specific attention is directed toward consideration of who might be classified as a human factors specialist, why human factors expertise is critical to the success of the HLRW management system, and determining when human factors specialists should become involved in the design and development process.

  15. Southern routes for high-level radioactive waste: Agencies, contacts, and designations

    SciTech Connect

    Not Available

    1991-05-01

    The Southern Routes for High-Level Radioactive Waste: Agencies, Contacts and Designations is a compendium of sixteen southern states' routing programs for the transportation of high-level radioactive materials. The report identifies the state-designated routing agencies as defined under 49 Code of Federal Regulations (CFR) Part 171 and provides a reference to the source and scope of the agencies' rulemaking authority. Additionally, the state agency and contact designated by the state's governor to receive advance notification and shipment routing information under 10 CFR Parts 71 and 73 are also listed. This report also examines alternative route designations made by southern states and the lessons that were learned from the designation process.

  16. Southern routes for high-level radioactive waste: Agencies, contacts, and designations

    SciTech Connect

    Not Available

    1991-05-01

    The Southern Routes for High-Level Radioactive Waste: Agencies, Contacts and Designations is a compendium of sixteen southern states` routing programs for the transportation of high-level radioactive materials. The report identifies the state-designated routing agencies as defined under 49 Code of Federal Regulations (CFR) Part 171 and provides a reference to the source and scope of the agencies` rulemaking authority. Additionally, the state agency and contact designated by the state`s governor to receive advance notification and shipment routing information under 10 CFR Parts 71 and 73 are also listed. This report also examines alternative route designations made by southern states and the lessons that were learned from the designation process.

  17. Unusually high levels of n-6 polyunsaturated fatty acids in whale sharks and reef manta rays.

    PubMed

    Couturier, L I E; Rohner, C A; Richardson, A J; Pierce, S J; Marshall, A D; Jaine, F R A; Townsend, K A; Bennett, M B; Weeks, S J; Nichols, P D

    2013-10-01

    Fatty acid (FA) signature analysis has been increasingly used to assess dietary preferences and trophodynamics in marine animals. We investigated FA signatures of connective tissue of the whale shark Rhincodon typus and muscle tissue of the reef manta ray Manta alfredi. We found high levels of n-6 polyunsaturated fatty acids (PUFA), dominated by arachidonic acid (20:4n-6; 12-17 % of total FA), and comparatively lower levels of the essential n-3 PUFA-eicosapentaenoic acid (20:5n-3; ~1 %) and docosahexaenoic acid (22:6n-3; 3-10 %). Whale sharks and reef manta rays are regularly observed feeding on surface aggregations of coastal crustacean zooplankton during the day, which generally have FA profiles dominated by n-3 PUFA. The high levels of n-6 PUFA in both giant elasmobranchs raise new questions about the origin of their main food source.

  18. Using the high-level based program interface to facilitate the large scale scientific computing.

    PubMed

    Shang, Yizi; Shang, Ling; Gao, Chuanchang; Lu, Guiming; Ye, Yuntao; Jia, Dongdong

    2014-01-01

    This paper is to make further research on facilitating the large-scale scientific computing on the grid and the desktop grid platform. The related issues include the programming method, the overhead of the high-level program interface based middleware, and the data anticipate migration. The block based Gauss Jordan algorithm as a real example of large-scale scientific computing is used to evaluate those issues presented above. The results show that the high-level based program interface makes the complex scientific applications on large-scale scientific platform easier, though a little overhead is unavoidable. Also, the data anticipation migration mechanism can improve the efficiency of the platform which needs to process big data based scientific applications.

  19. Using the High-Level Based Program Interface to Facilitate the Large Scale Scientific Computing

    PubMed Central

    Shang, Yizi; Shang, Ling; Gao, Chuanchang; Lu, Guiming; Ye, Yuntao; Jia, Dongdong

    2014-01-01

    This paper is to make further research on facilitating the large-scale scientific computing on the grid and the desktop grid platform. The related issues include the programming method, the overhead of the high-level program interface based middleware, and the data anticipate migration. The block based Gauss Jordan algorithm as a real example of large-scale scientific computing is used to evaluate those issues presented above. The results show that the high-level based program interface makes the complex scientific applications on large-scale scientific platform easier, though a little overhead is unavoidable. Also, the data anticipation migration mechanism can improve the efficiency of the platform which needs to process big data based scientific applications. PMID:24574931

  20. Decision Plan for West Valley High-Level Waste Tank Lay-Up

    SciTech Connect

    Elmore, Monte R.; Henderson, Colin

    2002-06-21

    Documents completion of Milestone A.3-1, "Issue Decision Plan for WVDP Tank Lay-Up," in Technical Task Plan RL30WT21A, "Post-Retrieval and Pre-Closure HLW Tank Lay-Up." This task is a collaborative effort among, Pacific Northwest National Laboratory, Jacobs Engineering Group Inc., and West Valley Nuclear Services. Thi primary objective of the overall task is to develop and evaluate conceptual strategies for preclosure lay-up of the two large high-level waste storage tanks at the West Valley Demonstration Project. Functions and requirments for tank lay-up were developed and previously documented in "Functions and Requirements for WVDP Lay-Up". These functions nad requirments served as the basis for cristeria to evaluate potential aly-up options documented in "West Valey High-Level Waste Tank Lay-Up Strategies".