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Song SY, Martiny JHJ, Kreisel A, Andersen BM, Seo J. Visualization of Local Magnetic Moments Emerging from Impurities in Hund's Metal States of FeSe. Phys Rev Lett 2020; 124:117001. [PMID: 32242691 DOI: 10.1103/physrevlett.124.117001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/30/2019] [Accepted: 02/21/2020] [Indexed: 06/11/2023]
Abstract
Understanding the origin of the magnetism of high temperature superconductors is crucial for establishing their unconventional pairing mechanism. Recently, theory predicts that FeSe is close to a magnetic quantum critical point, and thus weak perturbations such as impurities could induce local magnetic moments. To elucidate such quantum instability, we have employed scanning tunneling microscopy and spectroscopy. In particular, we have grown FeSe film on superconducting Pb(111) using molecular beam epitaxy and investigated magnetic excitation caused by impurities in the proximity-induced superconducting gap of FeSe. Our study provides deep insight into the origin of the magnetic ordering of FeSe by showing the way local magnetic moments develop in response to impurities near the magnetic quantum critical point.
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Affiliation(s)
- Sang Yong Song
- Department of Emerging Materials Science, DGIST, 333 Techno-Jungang-daero, Hyeonpung-Eup, Dalseong-Gun, Daegu 42988, Korea
| | - J H J Martiny
- Center for Nanostructured Graphene (CNG), Department of Physics, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - A Kreisel
- Institut für Theoretische Physik, Universität Leipzig, D-04103 Leipzig, Germany
| | - B M Andersen
- Niels Bohr Institute, University of Copenhagen, Lyngbyvej 2, DK-2100 Copenhagen, Denmark
| | - Jungpil Seo
- Department of Emerging Materials Science, DGIST, 333 Techno-Jungang-daero, Hyeonpung-Eup, Dalseong-Gun, Daegu 42988, Korea
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Rømer AT, Scherer DD, Eremin IM, Hirschfeld PJ, Andersen BM. Knight Shift and Leading Superconducting Instability from Spin Fluctuations in Sr_{2}RuO_{4}. Phys Rev Lett 2019; 123:247001. [PMID: 31922834 DOI: 10.1103/physrevlett.123.247001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Indexed: 06/10/2023]
Abstract
Recent nuclear magnetic resonance studies [A. Pustogow et al., Nature 574, 72 (2019)] have challenged the prevalent chiral triplet pairing scenario proposed for Sr_{2}RuO_{4}. To provide guidance from microscopic theory as to which other pair states might be compatible with the new data, we perform a detailed theoretical study of spin fluctuation mediated pairing for this compound. We map out the phase diagram as a function of spin-orbit coupling, interaction parameters, and band structure properties over physically reasonable ranges, comparing when possible with photoemission and inelastic neutron scattering data information. We find that even-parity pseudospin singlet solutions dominate large regions of the phase diagram, but in certain regimes spin-orbit coupling favors a near-nodal odd-parity triplet superconducting state, which is either helical or chiral depending on the proximity of the γ band to the van Hove points. A surprising near degeneracy of the nodal s^{'} and d_{x^{2}-y^{2}} wave solutions leads to the possibility of a near-nodal time-reversal symmetry broken s^{'}+id_{x^{2}-y^{2}} pair state. Predictions for the temperature dependence of the Knight shift for fields in and out of plane are presented for all states.
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Affiliation(s)
- A T Rømer
- Niels Bohr Institute, University of Copenhagen, Vibenhuset, Lyngbyvej 2, DK-2100 Copenhagen, Denmark
- Institut Laue-Langevin, 71 avenue des Martyrs CS 20156, 38042 Grenoble Cedex 9, France
| | - D D Scherer
- Niels Bohr Institute, University of Copenhagen, Vibenhuset, Lyngbyvej 2, DK-2100 Copenhagen, Denmark
| | - I M Eremin
- Institut für Theoretische Physik III, Ruhr-Universität Bochum, D-44801 Bochum, Germany
- National University of Science and Technology MISiS, 119049 Moscow, Russia
| | - P J Hirschfeld
- Department of Physics, University of Florida, Gainesville, Florida 32611, USA
| | - B M Andersen
- Niels Bohr Institute, University of Copenhagen, Vibenhuset, Lyngbyvej 2, DK-2100 Copenhagen, Denmark
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Kostin A, Sprau PO, Kreisel A, Chong YX, Böhmer AE, Canfield PC, Hirschfeld PJ, Andersen BM, Davis JCS. Imaging orbital-selective quasiparticles in the Hund's metal state of FeSe. Nat Mater 2018; 17:869-874. [PMID: 30177690 DOI: 10.1038/s41563-018-0151-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 07/24/2018] [Indexed: 06/08/2023]
Abstract
Strong electronic correlations, emerging from the parent Mott insulator phase, are key to copper-based high-temperature superconductivity. By contrast, the parent phase of an iron-based high-temperature superconductor is never a correlated insulator. However, this distinction may be deceptive because Fe has five actived d orbitals while Cu has only one. In theory, such orbital multiplicity can generate a Hund's metal state, in which alignment of the Fe spins suppresses inter-orbital fluctuations, producing orbitally selective strong correlations. The spectral weights Zm of quasiparticles associated with different Fe orbitals m should then be radically different. Here we use quasiparticle scattering interference resolved by orbital content to explore these predictions in FeSe. Signatures of strong, orbitally selective differences of quasiparticle Zm appear on all detectable bands over a wide energy range. Further, the quasiparticle interference amplitudes reveal that [Formula: see text], consistent with earlier orbital-selective Cooper pairing studies. Thus, orbital-selective strong correlations dominate the parent state of iron-based high-temperature superconductivity in FeSe.
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Affiliation(s)
- A Kostin
- Department of Physics, Cornell University, Ithaca, NY, USA
- CMPMS Department, Brookhaven National Laboratory, Upton, NY, USA
| | - P O Sprau
- Department of Physics, Cornell University, Ithaca, NY, USA
- CMPMS Department, Brookhaven National Laboratory, Upton, NY, USA
| | - A Kreisel
- Institut für Theoretische Physik, Universität Leipzig, Leipzig, Germany
| | - Yi Xue Chong
- Department of Physics, Cornell University, Ithaca, NY, USA
- CMPMS Department, Brookhaven National Laboratory, Upton, NY, USA
| | - A E Böhmer
- Ames Laboratory, U.S. Department of Energy, Ames, IA, USA
- Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - P C Canfield
- Ames Laboratory, U.S. Department of Energy, Ames, IA, USA
- Department of Physics and Astronomy, Iowa State University, Ames, IA, USA
| | - P J Hirschfeld
- Department of Physics, University of Florida, Gainesville, FL, USA
| | - B M Andersen
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - J C Séamus Davis
- Department of Physics, Cornell University, Ithaca, NY, USA.
- CMPMS Department, Brookhaven National Laboratory, Upton, NY, USA.
- School of Physics and Astronomy, University of St. Andrews, Fife, UK.
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Sprau PO, Kostin A, Kreisel A, Böhmer AE, Taufour V, Canfield PC, Mukherjee S, Hirschfeld PJ, Andersen BM, Davis JCS. Discovery of orbital-selective Cooper pairing in FeSe. Science 2018; 357:75-80. [PMID: 28684522 DOI: 10.1126/science.aal1575] [Citation(s) in RCA: 236] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 06/05/2017] [Indexed: 11/02/2022]
Abstract
The superconductor iron selenide (FeSe) is of intense interest owing to its unusual nonmagnetic nematic state and potential for high-temperature superconductivity. But its Cooper pairing mechanism has not been determined. We used Bogoliubov quasiparticle interference imaging to determine the Fermi surface geometry of the electronic bands surrounding the Γ = (0, 0) and X = (π/aFe, 0) points of FeSe and to measure the corresponding superconducting energy gaps. We show that both gaps are extremely anisotropic but nodeless and that they exhibit gap maxima oriented orthogonally in momentum space. Moreover, by implementing a novel technique, we demonstrate that these gaps have opposite sign with respect to each other. This complex gap configuration reveals the existence of orbital-selective Cooper pairing that, in FeSe, is based preferentially on electrons from the d yz orbitals of the iron atoms.
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Affiliation(s)
- P O Sprau
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA.,Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - A Kostin
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA.,Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - A Kreisel
- Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK 2100 Copenhagen, Denmark.,Institut für Theoretische Physik, Universität Leipzig, D-04103 Leipzig, Germany
| | - A E Böhmer
- Ames Laboratory, U.S. Department of Energy, Ames, IA 50011, USA
| | - V Taufour
- Ames Laboratory, U.S. Department of Energy, Ames, IA 50011, USA
| | - P C Canfield
- Ames Laboratory, U.S. Department of Energy, Ames, IA 50011, USA.,Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA
| | - S Mukherjee
- Department of Physics, Binghamton University-State University of New York, Binghamton, NY, USA
| | - P J Hirschfeld
- Department of Physics, University of Florida, Gainesville, FL 32611, USA
| | - B M Andersen
- Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK 2100 Copenhagen, Denmark
| | - J C Séamus Davis
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853, USA. .,Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA.,School of Physics and Astronomy, University of St Andrews, Fife KY16 9SS, Scotland.,Tyndall National Institute, University College Cork, Cork T12R5C, Ireland
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Andersen BM, Bånrud H, Bøe E, Bjordal O, Drangsholt F. Comparison of UV C Light and Chemicals for Disinfection of Surfaces in Hospital Isolation Units. Infect Control Hosp Epidemiol 2016; 27:729-34. [PMID: 16807849 DOI: 10.1086/503643] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Accepted: 01/04/2005] [Indexed: 11/04/2022]
Abstract
Objective.To determine the bactericidal effect on surfaces of ceiling- and wall-mounted UV C (UVC) light (wavelength, 254 nm) in isolation units, compared with standard hospital environmental cleaning and chemical disinfection during final disinfection after patients are treated for infections.Design.Microbial samples were obtained from surfaces in isolation units (patient room, anteroom, and bathroom) before and after irradiation with UVC, chloramine disinfection, and standard hospital environmental cleaning. Samples were tested using standard contact plates.Setting.Four identical, negative air-pressure isolation units (patient room, anteroom, and bathroom) with a defined number of ceiling-and wall-mounted UVC light units. The UVC distribution was monitored in one isolation unit after irradiation for approximately 40 minutes, corresponding to doses ranging from 160 J/m2in a shadowed area to 19,230 J/m2at the mostly highly exposed site (which is high enough to inactivate most bacterial organisms, including spores).Results.UVC disinfection significantly reduced the number of bacteria on surfaces directly or indirectly exposed to UVC to a very low number, as did 5% chloramine disinfection alone (P<.001 for both). Completely shadowed areas in the isolation unit (eg, the bed rail, lockers, and mattresses) still required disinfection by chemicals.Conclusion.Disinfection with UVC light may significantly reduce environmental bacterial contamination and thereby protect the next patient housed in an isolation room. UVC disinfection may not be used alone but is a good addition to chemical disinfection.
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Affiliation(s)
- B M Andersen
- Department of Hospital Infections, Ullevål University Hospital, Oslo, Norway
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Viskadourakis Z, Sunku SS, Mukherjee S, Andersen BM, Ito T, Sasagawa T, Panagopoulos C. Ferroelectricity in underdoped La-based cuprates. Sci Rep 2015; 5:15268. [PMID: 26486276 PMCID: PMC4614081 DOI: 10.1038/srep15268] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 09/03/2015] [Indexed: 12/02/2022] Open
Abstract
Doping a “parent” antiferromagnetic Mott insulator in cuprates leads to short-range electronic correlations and eventually to high-Tc superconductivity. However, the nature of charge correlations in the lightly doped cuprates remains unclear. Understanding the intermediate electronic phase in the phase diagram (between the parent insulator and the high-Tc superconductor) is expected to elucidate the complexity both inside and outside the superconducting dome, and in particular in the underdoped region. One such phase is ferroelectricity whose origin and relation to the properties of high-Tc superconductors is subject of current research. Here we demonstrate that ferroelectricity and the associated magnetoelectric coupling are in fact common in La-214 cuprates namely, La2-xSrxCuO4, La2LixCu1-xO4 and La2CuO4+x. It is proposed that ferroelectricity may result from local CuO6 octahedral distortions, associated with the dopant atoms and clustering of the doped charge carriers, which break spatial inversion symmetry at the local scale whereas magnetoelectric coupling can be tuned through Dzyaloshinskii-Moriya interaction.
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Affiliation(s)
- Z Viskadourakis
- Crete Center for Quantum Complexity and Nanotechnology, University of Crete, Heraklion 71003, Greece.,IESL-FORTH, Vassilika Vouton, Heraklion 71110, Greece
| | - S S Sunku
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
| | - S Mukherjee
- Niels Bohr Institute, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - B M Andersen
- Niels Bohr Institute, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - T Ito
- National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8562, Japan
| | - T Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan
| | - C Panagopoulos
- Crete Center for Quantum Complexity and Nanotechnology, University of Crete, Heraklion 71003, Greece.,Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore.,Department of Physics, University of Crete, Heraklion 71003, Greece
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Kreisel A, Choubey P, Berlijn T, Ku W, Andersen BM, Hirschfeld PJ. Interpretation of scanning tunneling quasiparticle interference and impurity states in cuprates. Phys Rev Lett 2015; 114:217002. [PMID: 26066452 DOI: 10.1103/physrevlett.114.217002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Indexed: 06/04/2023]
Abstract
We apply a recently developed method combining first principles based Wannier functions with solutions to the Bogoliubov-de Gennes equations to the problem of interpreting STM data in cuprate superconductors. We show that the observed images of Zn on the surface of Bi_{2}Sr_{2}CaCu_{2}O_{8} can only be understood by accounting for the tails of the Cu Wannier functions, which include significant weight on apical O sites in neighboring unit cells. This calculation thus puts earlier crude "filter" theories on a microscopic foundation and solves a long-standing puzzle. We then study quasiparticle interference phenomena induced by out-of-plane weak potential scatterers, and show how patterns long observed in cuprates can be understood in terms of the interference of Wannier functions above the surface. Our results show excellent agreement with experiment and enable a better understanding of novel phenomena in the cuprates via STM imaging.
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Affiliation(s)
- A Kreisel
- Department of Physics, University of Florida, Gainesville, Florida 32611, USA
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Peayush Choubey
- Department of Physics, University of Florida, Gainesville, Florida 32611, USA
| | - T Berlijn
- Center for Nanophase Materials Sciences and Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - W Ku
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - B M Andersen
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - P J Hirschfeld
- Department of Physics, University of Florida, Gainesville, Florida 32611, USA
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Atkinson WA, Bazak JD, Andersen BM. Robust nodal d-wave spectrum in simulations of a strongly fluctuating competing order in underdoped cuprate superconductors. Phys Rev Lett 2012; 109:267004. [PMID: 23368606 DOI: 10.1103/physrevlett.109.267004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Indexed: 06/01/2023]
Abstract
We resolve an existing discrepancy between convincing evidence for competing order in underdoped cuprates and spectroscopic data consistent with a homogeneous d-wave superconductor in the very same compounds. Specifically, we show that fluctuations of the competing order generate strongly inhomogeneous states whose spectra are almost indistinguishable from the pure d-wave superconductor. This is in contrast to the commonly studied case of homogeneously coexisting order, which typically generates a reconstructed Fermi surface with closed Fermi pockets. The signatures of the fluctuating competing order can be found mainly in a splitting of the antinodal band, and, for strong magnetic order, in small induced nodal gaps similar to those found in recent experiments on underdoped La(2-x)Sr(x)CuO4.
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Affiliation(s)
- W A Atkinson
- Department of Physics and Astronomy, Trent University, Peterborough, Ontario, Canada K9J 7B8.
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Andersen BM, Flensberg K, Koerting V, Paaske J. Nonequilibrium transport through a spinful quantum dot with superconducting leads. Phys Rev Lett 2011; 107:256802. [PMID: 22243100 DOI: 10.1103/physrevlett.107.256802] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Indexed: 05/31/2023]
Abstract
We study the nonlinear cotunneling current through a spinful quantum dot contacted by two superconducting leads. Applying a general nonequilibrium Green function formalism to an effective Kondo model, we study the rich variation in the IV characteristics with varying asymmetry in the tunnel coupling to source and drain electrodes. The current is found to be carried, respectively, by multiple Andreev reflections in the symmetric limit, and by spin-induced Yu-Shiba-Rusinov bound states in the strongly asymmetric limit. The interplay between these two mechanisms leads to qualitatively different IV characteristics in the crossover regime of intermediate symmetry, consistent with recent experimental observations of negative differential conductance and repositioned conductance peaks in subgap cotunneling spectroscopy.
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Affiliation(s)
- B M Andersen
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
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Hickey MJ, Malone CK, Erickson KL, Gerschenson LE, Lin AH, Inagaki A, Hiraoka K, Kasahara N, Mueller B, Kruse CA, Kong S, Tyler B, Zhou J, Carter BS, Brem H, Junghans RP, Sampath P, Lai RK, Recht LD, Reardon DA, Paleologos N, Groves M, Rosenfeld MR, Davis T, Green J, Heimberger A, Sampson J, Hashimoto N, Tsuboi A, Chiba Y, Kijima N, Oka Y, Kinoshita M, Kagawa N, Fujimoto Y, Sugiyama H, Yoshimine T, Birks SM, Burnet M, Pilkington GJ, Yu JS, Wheeler CJ, Rudnick J, Mazer M, Wang HQ, Nuno MA, Richardson JE, Fan X, Ji J, Chu RM, Bender JG, Hawkins EW, Black KL, Phuphanich S, Pollack IF, Jakacki RI, Butterfield LH, Okada H, Hunt MA, Pluhar GE, Andersen BM, Gallardo JL, Seiler CO, SantaCruz KS, Ohlfest JR, Bauer DF, Lamb LS, Harmon DK, Zheng X, Romeo AK, Gillespie GY, Parker JN, Markert JM, Jacobs VL, Landry RP, De Leo JA, Bromberg JE, Doorduijn J, Baars JW, van Imhoff GW, Enting R, van den Bent MJ, Murphy KA, Bedi J, Epstein A, Ohlfest JR, Olin M, Andersen B, Swier L, Ohlfest J, Litterman AJ, Zellmer DM, Ohlfest JR, Chiocca EA, Aguilar LK, Aguilar-Cordova E, Manzanera AG, Harney KR, Portnow J, Badie B, Lesniak M, Bell S, Ray-Chaudhuri A, Kaur B, Hardcastle J, Cavaliere R, McGregor J, Lo S, Chakarvarti A, Grecula J, Newton H, Trask TW, Baskin DS, New PZ, Zeng J, See AP, Phallen J, Belcaid Z, Durham N, Meyer C, Albesiano E, Pradilla G, Ford E, Hammers H, Tyler B, Brem H, Tran PT, Pardoll D, Drake CG, Lim M, Ghazi A, Ashoori A, Hanley P, Salsman V, Schaffer DR, Grada Z, Kew Y, Powell SZ, Grossman R, Scheurer ME, Leen AM, Rooney CM, Bollard CM, Heslop HE, Gottschalk S, Ahmed N, Hu J, Patil C, Nuno M, Wheeler C, Rudnick J, Phuphanich S, Mazer M, Wang HQ, Chu R, Black K, Yu J, Marabelle A, Kohrt H, Brody J, Luong R, Tse V, Levy R, Li YM, Jun H, Shahryar M, Daniel VA, Walter HA, Thaipisuttikul I, Avila E, Mitchell DA, Archer GE, Friedman HS, Herndon JE, Bigner DD, Sampson JH, Johnson LA, Archer GE, Nair SK, Schmittling R, Reap E, Sampson JH, Mitchell DA, Li YM, Shahryar M, Jun H, Daniel VA, Walter HA, Knisely JP, Kluger H, Flanigan J, Sznol M, Yu JB, Chiang VL, Prins RM, Kim W, Soto H, Lisiero DN, Lisiero DN, Liau LM. IMMUNOTHERAPY. Neuro Oncol 2011; 13:iii34-iii40. [PMCID: PMC3199174 DOI: 10.1093/neuonc/nor151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023] Open
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Fujita M, Kohanbash G, McDonald HA, Delamarre L, Decker SA, Ohlfest JR, Okada H, Okada H, Kalinski P, Ueda R, Hoji A, Kohanbash G, Donegan TE, Mintz AH, Engh JA, Bartlett DL, Brown CK, Zeh H, Holtzman MP, Reinhart TA, Whiteside TL, Butterfield LH, Hamilton RL, Potter DM, Pollack IF, Salazar AM, Lieberman FS, Olin MR, Andersen BM, Grogan PT, Hunt M, Popescu FE, Xiong ZL, Seiler C, Forster CL, SantaCruz KS, Chen W, Blazar BR, Ohlfest JR, Hu J, Wheeler CJ, Phuphanich S, Rudnick J, Nuno M, Serrano N, Dantis J, Richardson J, Mazer M, Wang HQ, Chu R, Black KL, Yu J, Li YM, Vallera DA, Hall WA, Rudnick JD, Wheeler CJ, Phuphanich S, Chu RM, Mazer M, Wang H, Serrano N, Nuno M, Richardson J, Hu J, Black KL, Yu JS, Yang I, Han S, Tihan T, Wrensch M, Parsa AT, Li YM, Vallera DA, Hall WA, Andersen BM, Hunt MA, Gallardo JL, Seiler C, Pluhar GE, Ohlfest JR, Brown CE, Starr R, Martinez C, Bading J, Ressler JA, Badie B, Jensen MC, Glick RP, Ksendzovsky A, Zengou R, Polak P, Simonini V, Lichtor T, Feinstein D, Chow KK, Ahmed N, Salsman VS, Kew Y, Powell S, Grossman R, Heslop HE, Gottschalk S, Barnett FH, Marchetti V, Wang M, Johnson A, Scheppke L, Jacobson R, Nemerow G, Friedlander M, Ahmed N, Salsman V, Kew Y, Leen AM, Bollard CM, Powell S, Grossman R, Rooney C, Heslop HE, Gottschalk S, New PZ, Bollard CM, Salvoldo B, Heslop H. Immunotherapy. Neuro Oncol 2010. [DOI: 10.1093/neuonc/noq116.s5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Andersen BM, Tollefsen T, Seljordslia B, Hochlin K, Syversen G, Jonassen TØ, Rasch M, Sandvik L. Rapid MRSA test in exposed persons: costs and savings in hospitals. J Infect 2010; 60:293-9. [PMID: 20122959 DOI: 10.1016/j.jinf.2010.01.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 01/21/2010] [Accepted: 01/23/2010] [Indexed: 10/19/2022]
Abstract
OBJECTIVE To study a rapid Xpert polymerase chain reaction (PCR) method in detecting methicillin-resistant Staphylococcus aureus (MRSA) in patients and healthcare workers (HCW) exposed to MRSA, and to estimate savings associated to isolation or work restriction. METHODS A test set of four double (one for the growth and one for the rapid test) pre-wet swabs from the nose, throat, hands/wrists and perineum was studied by a growth method and by the Xpert MRSA test. RESULTS The total correspondence between the growth and the rapid test was 92.8%. The overall sensitivity, specificity, positive and negative predictive values were for the Xpert MRSA test: 87%, 99.6%, 68.5% and 99.9%, and for the growth test: 76%, 100%, 100%, and 99.8%, assuming a prevalence of MRSA of 0.01%. Among the MRSA positive persons, the Xpert and growth tests detected MRSA in 44.6% and 40% of nose samples, respectively, 38.2% and 45.5% throat samples, 30.8% and 11.5% hands/wrists samples, 44% and 38% perineum samples, and in 81.8% and 77.3% wound samples, respectively. By combining four anatomical sites, the detection rate increased to 87.5% by both methods. The cost for each Xpert and growth test was euro50 and euro6.25, respectively. The rapid test would save at least euro925 per exposed HCW and euro550 per patient that were MRSA negative. CONCLUSION The MRSA Xpert test is easy to perform, has a high negative predictive value, and may be used to control healthcare workers and patients exposed to MRSA. Sampling from multiple anatomical locations is recommended. Still, more then 10% of MRSA positive cases may not be found.
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Affiliation(s)
- B M Andersen
- Department of Hospital Infections, Oslo University Hospital - Ullevål, Oslo, Norway.
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Andersen BM, Rasch M, Hochlin K, Tollefsen T, Sandvik L. Hospital-acquired infections before and after healthcare reorganization in a tertiary university hospital in Norway. J Public Health (Oxf) 2008; 31:98-104. [DOI: 10.1093/pubmed/fdn113] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Sie I, Thorstad M, Andersen BM. Infection control and meticillin-resistant Staphylococcus aureus in nursing homes in Oslo. J Hosp Infect 2008; 70:235-40. [PMID: 18786745 DOI: 10.1016/j.jhin.2008.06.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 06/06/2008] [Indexed: 10/21/2022]
Abstract
Healthcare workers (HCWs) might be important in reducing healthcare-associated infections but infected or colonised HCWs may still spread pathogenic microbes to others. Norwegian policies for infection control in healthcare environments emphasise infection control programmes for both patients and HCWs. In this study, HCWs from 42 of 55 nursing homes in Oslo participated in an investigation concerning the implementation of infection control programmes during 2006-2007. Three separate questionnaires were used: the first aimed at nursing staff (enrolled nurses and assisting staff); the second for ward sisters; and the third for institution managers. Nearly 70% of the nursing homes had policies for controlling infection and transmission of meticillin-resistant Staphylococcus aureus (MRSA). About 60% of the institutions had policies for tracing MRSA infections. Four of five ward sisters tested patients for MRSA when wounds were not healing, when admitted from hospitals overseas, when patients shared a room with an MRSA-infected patient, or if patients had ever been MRSA positive. Two of five sisters would test patients with chronic urinary tract infection or patients admitted from another hospital. Among nursing staff, one out of five had cared for MRSA-positive patients. Only 4% of the staff had worked in healthcare institutions abroad, and only a few of them had been tested for MRSA. Almost 20% of the responding nursing staff worked at several institutions at the same time.
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Affiliation(s)
- I Sie
- Nursing College, Diakonova University College, Oslo, Norway.
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15
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Sand-Jespersen T, Paaske J, Andersen BM, Grove-Rasmussen K, Jørgensen HI, Aagesen M, Sørensen CB, Lindelof PE, Flensberg K, Nygård J. Kondo-enhanced Andreev tunneling in InAs nanowire quantum dots. Phys Rev Lett 2007; 99:126603. [PMID: 17930535 DOI: 10.1103/physrevlett.99.126603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2007] [Indexed: 05/25/2023]
Abstract
We report measurements of the nonlinear conductance of InAs nanowire quantum dots coupled to superconducting leads. We observe a clear alternation between odd and even occupation of the dot, with subgap peaks at |V(sd)| = Delta/e markedly stronger (weaker) than the quasiparticle tunneling peaks at |V(sd)| = 2Delta/e for odd (even) occupation. We attribute the enhanced Delta peak to an interplay between Kondo correlations and Andreev tunneling in dots with an odd number of spins, and we substantiate this interpretation by a poor man's scaling analysis.
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Affiliation(s)
- T Sand-Jespersen
- Nano-Science Center, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
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16
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Andersen BM, Rasch M, Hochlin K, Jensen FH, Wismar P, Fredriksen JE. Decontamination of rooms, medical equipment and ambulances using an aerosol of hydrogen peroxide disinfectant. J Hosp Infect 2005; 62:149-55. [PMID: 16337307 PMCID: PMC7114946 DOI: 10.1016/j.jhin.2005.07.020] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2004] [Accepted: 07/01/2005] [Indexed: 11/22/2022]
Abstract
A programmable device (Sterinis, Gloster Sante Europe) providing a dry fume of 5% hydrogen peroxide (H2O2) disinfectant was tested for decontamination of rooms, ambulances and different types of medical equipment. Pre-set concentrations were used according to the volumes of the rooms and garages. Three cycles were performed with increasing contact times. Repetitive experiments were performed using Bacillus atrophaeus (formerly Bacillus subtilis) Raven 1162282 spores to control the effect of decontamination; after a sampling plan, spore strips were placed in various positions in rooms, ambulances, and inside and outside the items of medical equipment. Decontamination was effective in 87% of 146 spore tests in closed test rooms and in 100% of 48 tests in a surgical department when using three cycles. One or two cycles had no effect. The sporicidal effect on internal parts of the medical equipment was only 62.3% (220 tests). When the devices were run and ventilated during decontamination, 100% (57/57) of spore strips placed inside were decontaminated. In the ambulances, the penetration of H2O2 into equipment, devices, glove boxes, under mattresses, and the drivers' cabins was 100% (60/60 tests) when using three cycles, but was less effective when using one or two cycles. In conclusion, an H2O2 dry fumigation system, run in three cycles, seemed to have a good sporicidal effect when used in rooms, ambulances, and external and internal parts of ventilated equipment. Further studies need to be performed concerning concentration, contact time and the number of cycles of H2O2. This is especially important for inner parts of medical equipment that cannot be ventilated during the decontamination process.
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Affiliation(s)
- B M Andersen
- Department of Hospital Infection, Ullevål University Hospital, Oslo, Norway.
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17
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Andersen BM, Lindemann R, Bergh K, Nesheim BI, Syversen G, Solheim N, Laugerud F. Spread of methicillin-resistant Staphylococcus aureus in a neonatal intensive unit associated with understaffing, overcrowding and mixing of patients. J Hosp Infect 2002; 50:18-24. [PMID: 11825047 DOI: 10.1053/jhin.2001.1128] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Over the period May-June 1999, an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) was registered in eight newborns in a neonatal intensive care unit (NICU) at the Department of Pediatrics, Ullevål University Hospital (UUH) in Oslo. Seven were infected or colonized with an indistinguishable strain, detected at the NICU, and one patient with a slightly different PFGE type (i.e. a subtype) was registered at the outpatient clinic. The MRSA strains resembled the sensitive, inbred 'Norwegian type' described four years earlier at UUH, showing a relatively low and heterogenic methicillin resistance (MIC 12-96 mg/L), and susceptibility to most other anti-staphylococcal agents. Before and during the outbreak, there was high activity, understaffing, overcrowding and a mix of patients; 42% of the staff were relatively untrained, and up to 62% (during weekends) were extra nursing staff, partly from other Scandinavian countries. All cases were isolated (air and contact isolation), and all other patients and personnel were treated as being exposed to MRSA (isolated from other departments) until the last patient had been identified, disinfection of all rooms was complete, and all screening samples from staff and other patients were negative. The NICU and the delivery suite were closed for one week for disinfection and screening. The outbreak ended after 34 days. Since then, two years later, no further cases have been detected in the NICU or the delivery suite.
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Affiliation(s)
- B M Andersen
- Department of Hospital Infection, Ullevål University Hospital, Oslo, Norway
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18
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Andersen BM, Syversen G. [Methicillin resistant Staphylococcus aureus in Oslo in 2000]. Tidsskr Nor Laegeforen 2001; 121:1844. [PMID: 11464698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
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19
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Andersen BM, Rasch M. Hospital-acquired infections in Norwegian long-term-care institutions. A three-year survey of hospital-acquired infections and antibiotic treatment in nursing/residential homes, including 4500 residents in Oslo. J Hosp Infect 2000; 46:288-96. [PMID: 11170760 DOI: 10.1053/jhin.2000.0840] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Point prevalence studies of hospital-acquired infections among the elderly in 65-70 long-term care facilities (LTCF) were carried out once a year over a three-year period in Oslo city, Norway. They showed an overall rate of 6.5% of hospital-acquired infections among 13 762 residents. The infection rate was approximately the same as in hospitals and twice as high as among hospitalized long-term psychiatric patients. Residents who had received surgical treatment within the previous three months had a high rate of postoperative infections, especially wound infections (14.8%). During the study period, the LTCFs were found to be understaffed and overcrowded. They had few private rooms, a lack of bathrooms and toilets, no isolation facilities and deficient ventilation systems. The economic consequences of hospital-acquired infections in these LTCFs were extra costs in medical and nursing care and antibacterial treatment of 157 500 Nkr/day (22500 USD). There would be a substantial cost-benefit in effective preventive measures against hospital-acquired infections in long-term care institutions.
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Affiliation(s)
- B M Andersen
- Department of Hospital Infection, Ullevål University Hospital, 0407, Oslo, Norway
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20
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Melby KK, Svendby JG, Eggebø T, Holmen LA, Andersen BM, Lind L, Sjøgren E, Kaijser B. Outbreak of Campylobacter infection in a subartic community. Eur J Clin Microbiol Infect Dis 2000; 19:542-4. [PMID: 10968326 DOI: 10.1007/s100960000316] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A presumably waterborne outbreak of Campylobacter jejuni/coli infection in a subarctic community is described. Drinking water supplied to residents was delivered unchlorinated during a 4-week period. No Campylobacter sp. was recovered from the water supply. Three hundred thirty individuals (15% of the 2,200 exposed) became ill. Diarrhoea, abdominal pain, fever, nausea and joint pain occurred in 81%, 30%, 29%, 43% and 21%, respectively. Nine percent reported swelling of joints, and two cases of reactive arthritis occurred. A Campylobacter sp. was isolated from 9 of 33 individuals who became ill and from 1 of 33 healthy controls. All culture-positive individuals, 46% of culture-negative ill persons and 27% of healthy controls were seropositive. All strains recovered had an identical DNA profile.
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Affiliation(s)
- K K Melby
- Department of Microbiology, Ullevaal University Hospital, Oslo, Norway.
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21
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Andersen BM, Haugen H, Rasch M, Heldal Haugen A, Tageson A. Outbreak of scabies in Norwegian nursing homes and home care patients: control and prevention. J Hosp Infect 2000; 45:160-4. [PMID: 10860693 DOI: 10.1053/jhin.1999.0716] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Over a period of five months (October 1998-February 1999), an outbreak of scabies affected 19 persons associated with a nursing home in Oslo, Norway. Scabies was diagnosed in 13 patients; six long-term patients, five short-term patients also cared for at home, and two home care patients associated with the same institution. Six healthcare workers who had assisted with infected patients in their own homes were also diagnosed with scabies. Two separate index cases were found. Both had had pruritus for several months, diagnosed as eczema, and were repeatedly treated at dermatology outpatient clinics before the diagnosis was made. Both index cases were cared for at home and in the nursing home (short-term). Repeated treatments with permethrin were tried before effective treatment with benzyl benzoate. Altogether 370 persons (patients, staff, relatives) were treated. In June-July 1999, scabies was diagnosed in two other nursing homes; six patients or staff, and 156 persons were treated. Patients with scabies were contact isolated and disinfection and cleaning was performed. Simultaneous treatment and washing or disinfection of clothing, bedding and environment of all potentially affected individuals is imperative to control an outbreak of scabies.
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Affiliation(s)
- B M Andersen
- Department of Hospital Infection, Ullevâl University Hospital, Oslo, 0407
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22
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Andersen BM, Ringertz SH, Gullord TP, Hermansen W, Lelek M, Norman BI, Nystad MT, Rød KA, Røed RT, Smidesang IJ, Solheim N, Tandberg S, Halsnes R, Wenche Høystad M. A three-year survey of nosocomial and community-acquired infections, antibiotic treatment and re-hospitalization in a Norwegian health region. J Hosp Infect 2000; 44:214-23. [PMID: 10706805 DOI: 10.1053/jhin.1999.0677] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In Norway, hospital-acquired infections (HAI) were analysed by repeated point prevalence studies (four each year) performed simultaneously at 14 hospitals in a health region (860,000 inhabitants) during the period 1996-1998. The study included 3200 beds and 121,000 discharged patients each year, and was initiated by and co-ordinated from the regional university hospital; Ullevål University Hospital (UHH). An overall prevalence rate of HAI of 6.5% (interhospital variation 1.4-11.7%) was found for the 32,248 patients studied. The rate of HAI was reduced from 7.7% in 1996 to 5. 9% in 1998. Smaller hospitals (<200 beds) generally had lower rates of HAI, community acquired infections (CAI), postoperative infections and use of antibacterial agents, than the large regional hospital (1200 beds). HAI was reduced in non-operated patients from 5.8% in 1996 to 4.4% in 1998 and in operated patients from 13.2% in 1996 to 10.5% in 1998. The risk of developing HAI was twice as high after surgery. From 1996 to 1998 there was a reduction in: urinary tract infections from 2.4% to 1.7%, lower respiratory tract infections from 1.5% to 0.8% and postoperative wound infections from 5.7% to 4.3%, while septicaemia (from 0.5% to 0.4%) remained unchanged. Re-hospitalization because of HAI was registered in 0.6% (interhospital variation 0.3-1.1%) of patients. The CAI rate in hospitals increased from 8.3% in 1996 to 10.8% in 1998. Approximately 16% (variation:14.4-20.6%) of the patients had an infection. The total use of antibacterial agents was 19.2% in 1996, 16.6% in 1997 and 17.8% in 1998 (variation: 14.9-23%).
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Affiliation(s)
- B M Andersen
- Department of Hospital infection, Ullevål University Hospital, Oslo, 0407, Norway
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23
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Andersen BM. [Influenza--preventive measures without effect?]. Tidsskr Nor Laegeforen 2000; 120:383. [PMID: 10827533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
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24
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Andersen BM, Rasch M. [Prevention of nosocomial influenza-like respiratory tract infections in nursing homes]. Tidsskr Nor Laegeforen 1999; 119:1336. [PMID: 10327862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
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25
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Simonsen GS, Andersen BM, Digranes A, Harthug S, Jacobsen T, Lingaas E, Natås OB, Olsvik O, Ringertz SH, Skulberg A, Syversen G, Sundsfjord A. Low faecal carrier rate of vancomycin resistant enterococci in Norwegian hospital patients. Scand J Infect Dis 1999; 30:465-8. [PMID: 10066045 DOI: 10.1080/00365549850161449] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The faecal carrier rate of vancomycin resistant enterococci (VRE) was surveyed among 616 patients in selected departments of 7 Norwegian hospitals. One Enterococcus gallinarum isolate harbouring a vanB2 element was recovered from a child with malignant disease treated with vancomycin and ceftazidime. No vancomycin resistant Enterococcus faecalis or Enterococcus faecium were detected and no VRE isolates of the VanA type were identified. The low level of VRE carriage corresponds to the limited use of glycopeptide antibiotics for human therapeutic purposes in Norway. It indicates a low risk of acquiring VRE infections in Norwegian hospitals.
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Affiliation(s)
- G S Simonsen
- Department of Microbiology, University Hospital of Tromso, Norway
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26
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Andersen BM, Bergh K, Steinbakk M, Syversen G, Magnaes B, Dalen H, Bruun JN. A Norwegian nosocomial outbreak of methicillin-resistant Staphylococcus aureus resistant to fusidic acid and susceptible to other antistaphylococcal agents. J Hosp Infect 1999; 41:123-32. [PMID: 10063474 DOI: 10.1016/s0195-6701(99)90049-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In Norway, infections caused by methicillin resistant Staphylococcus aureus (MRSA) are still uncommon. From December 1993 to January 1997, MRSA was isolated from 22 people in Oslo county; 17 patients and five carriers (healthcare workers). A cluster of ten people (five patients and five healthcare workers) were associated with an outbreak at two hospitals in Oslo. The five patients were all admitted to the same intensive care unit (ICU) at Ullevål University Hospital between May-July 1995 (they were not transferred from abroad) and treated for acute neurological lesions. After surgery, four of them (one died) were transferred to another hospital for rehabilitation and training. The presence of MRSA was discovered in the patients and the five healthcare workers during the 10 months June 1995-March 1996. All cluster strains showed an unusual antibiotic resistance pattern in vitro, with a relatively low degree of methicillin resistance, resistance to fusidic acid, but sensitivity to all other anti-staphylococcal agents. A clonal spread of this fusidic acid resistant MRSA was supported by strain typing using pulsed-field gel electrophoresis (PFGE), which showed that all ten cluster strains belonged to one type or its subtype.
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Affiliation(s)
- B M Andersen
- Department of Hospital Infections, Ullevål University Hospital, Oslo, Norway
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27
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Andersen BM. [Children in day care centers--antibacterial agents instead of good infection control?]. Tidsskr Nor Laegeforen 1999; 119:263. [PMID: 10081362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
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28
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Andersen BM. [Routines ordered by law for testing of potential disease transmission are not sufficient]. Tidsskr Nor Laegeforen 1999; 119:252-3. [PMID: 10081361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Affiliation(s)
- B M Andersen
- Avdeling for sykdomsforebygging hos riskogrupper, Klinikk for forebyggende medisin, Ullevål sykehus, Oslo
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29
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Abstract
Hospital infections were studied among 41,000 patients admitted to a 1,000-bed university hospital in Oslo, Norway. A prevalence rate of 8.5% in 1995 contributed to 14,500 days of extra stay in the hospital. The direct economic consequences of hospital infections was 40 to 50 million Norwegian kroner ($6-$7 million). The extra direct cost per infected patient was 14,300 Norwegian kroner ($2,200). Hospital infections are generating high extra costs and morbidity in countries with good general health care and with few problems with resistant bacteria.
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Affiliation(s)
- B M Andersen
- Clinic of Preventive Medicine, Department of Hospital Infections, Ullevål University Hospital, Oslo, Norway
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30
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Andersen BM, Røed RT, Solheim N, Levy F, Bratteberg A, Kristoffersen K, Moløkken I. [Air quality and microbiologic contamination in operating theatres]. Tidsskr Nor Laegeforen 1998; 118:3148-51. [PMID: 9760859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
The present study concerns the air quality and microbiological contamination in two newly built operating theatres; one with laminar air flow (LAF) equipment for cardio-thoracic operations, and one with conventional ventilation for urological operations. Both theatres had an identical number of air exchanges (17/h), identical microclimatic conditions and they employed the same cleaning procedures. In the LAF-ventilated operating theatre bacterial contamination of the air was effectively reduced to less than 10 colony-forming units (CFU)/m3 in all 125 samples (1 m3 per sample) tested. In most samples, 118/125, the bacterial count was less than 5 CFU/m3, despite the presence of ten persons. The conventionally ventilated theatre reached values up to 120 CFU/m3 during the most active period of the day when approximately seven persons were present. The LAF ventilation reduced both the content of particles in the air and contamination by bacteria on the floor. In both theatres cleaning procedures had only a low impact on CFU in the air and on the floor. The use of diathermia markedly increased the level of small particles in the air, and this may influence the air quality in the operating theatres.
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Affiliation(s)
- B M Andersen
- Avdeling for sykdomsforebygging hos risikogrupper, Ullevål sykehus, Oslo
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31
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Andersen BM, Dalen HE, Steinbakk M, Syversen G, Bruun JN, Magnaes B, Rasch M, Solheim N. [Methicillin resistant yellow staphylococci]. Tidsskr Nor Laegeforen 1998; 118:1182-5. [PMID: 9567693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The incidence of methicillin-resistant Staphylococcus aureus in Norway is extremely low. Isolation of such strains is nearly always associated with import. From December 1993 to January 1997 at the Ullevål University Hospital Department of Medical Microbiology, methicillin-resistant Staphylococcus aureus was isolated from 22 persons in Oslo (17 patients and five healthy carriers). A cluster of ten infected persons was detected (five patients and five carriers (nurses)) who were infected with strains showing an unusual antibiotic resistance pattern. All of the cluster strains except for beta-lactams were resistant to fucidic acid and sensitive to other antistaphylococcal agents. The cluster was associated with two hospitals. The five patients were all admitted to the same intensive care unit during the period May to July 1995. Four of the five patients (one died) were referred to the same department in a long-term care hospital for rehabilitation and training. Problems concerning epidemiological investigation and control are discussed.
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Affiliation(s)
- B M Andersen
- Seksjon for sykehushygiene, Klinikk for forebyggende medisin, Ullevål sykehus, Oslo
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32
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Schlichting E, Andersen BM. [Prevention of infections among surgeons]. Tidsskr Nor Laegeforen 1998; 118:416-8. [PMID: 9499733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Accidental exposure to blood may represent a frightening experience for health care workers because of the risk of developing infectious diseases, such as hepatitis B and C virus and HIV infection. Recommendations for follow-up after occupational exposure to HIV- and hepatitis infected blood are presented. Post-exposure chemoprophylaxis decreases the risk of occupational HIV infection after percutaneous exposure and should be administered within two hours. Studies have shown that most accidents could have been avoided with better working routines during operations.
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Andersen BM, Ree MH, Hermansen W, Ringertz SH, Høystad MW, Lelek M, Normann BI, Gullord TP, Rød KA, Røed R, Solheim N, Tandberg S, Bjørklund U, Hansen KS. [Hospital hygiene--number of hospital infections reduced last year]. Tidsskr Sykepl 1998; 86:52-4. [PMID: 9485952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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34
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Andersen BM, Ree MH, Hermansen W, Ringertz SH, Høystad MW, Lelek M, Normann BI, Naes B, Gullord TP, Rød KA, Røed R, Smidesang IJ, Solheim S, Tandberg S, Osten PE. [Hospital hygiene--hospital infections should be reduced]. Tidsskr Sykepl 1997; 85:53-5. [PMID: 9349038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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35
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Andersen BM. [Infected at work--an occupational hazard in health care]. Tidsskr Nor Laegeforen 1997; 117:2073. [PMID: 9235692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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36
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Hoel T, Andersen BM. [Malaria prophylaxis--correct information is important]. Tidsskr Nor Laegeforen 1997; 117:1001-2. [PMID: 9102992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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37
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Andersen BM, Solheim N, Krüger O, Levy F, Sogn K, Moløkken I. [Floor cleaning methods of patients' room. Effect on bacteria, dirt and particles]. Tidsskr Nor Laegeforen 1997; 117:838-41. [PMID: 9102982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The effect of floor cleaning on bacteria, organic materials and particles in the patients' rooms was studied at Ullevål University Hospital, Oslo, Norway. Four cleaning methods were compared; dust-adhesive (dry), humified, wet mopping, and regular wet washing (RWW) without a mop. The following tests were taken from the floor before and after cleaning: bacterial counts (colony forming units = CFU) and ATP (presence of organic materials), and from the air: CFU/m3 air, and particle counts/m3 air. Humified mopping and dry mopping reduced the bacterial counts from the floor by 75% and 55% respectively (p = 0.005 and p = 0.014, using contact medium). The wet mopping had no statistically significant effect, while the wet washing even increased the CFU on the floor by 35-50% (p = 0.017 with contact medium, and p = 0.028 with petrifilm). The two wet methods were the most effective, however, in removing organic materials from the floor; 65% to 70% reduction (p = 0.051 and p =0.008). The CFU/m3 air was low both before (50-130 CFU/m3) and after (70-110 CFU/m3) cleaning. A slight increase in airborne particles was measured after dry mopping. Combined use of humified mopping and wet mopping is recommended, but is dependent on a well prepared and finished floor surface.
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Affiliation(s)
- B M Andersen
- Seksjon for sykehushygiene, Ullevål sykehus, Oslo
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38
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Andersen BM. [Protection against pneumococcal disease. The vaccine is not the same as the influenza vaccine]. Tidsskr Nor Laegeforen 1997; 117:95. [PMID: 9064824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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39
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Andersen BM. [Nosocomial infections in Ullevål hospital. Occurrence and economic consequences]. Tidsskr Nor Laegeforen 1996; 116:2903-7. [PMID: 8975408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The present study concerns the prevalence, extra days in hospital, and direct extra costs of hospital infections in patients admitted to Ullevål University Hospital; a hospital with 1,000 beds in Oslo, Norway. Extra stay was calculated as mean of four extra days per patient or the extra stay connected with the different types of infection. Cost was determined as cost per day per patient in the different clinical departments, including all supportive services. Cost was also determined from the hospital's DRG-index (Diagnosis-Related Groups). A prevalence rate of 8.5% contributed in 1995 to 14,410 extra days in hospital, corrigated for the type of hospital infection. Calculated using a mean of four extra days per patient the figure was 14,000 extra days. In 1995, the direct economic consequence for the hospital was NOK 40-50 million (6-8 mill. US dollars).
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Affiliation(s)
- B M Andersen
- Seksjon for sykehushygiene Klinikk for forebyggende medisin Ullevål sykehus, Oslo
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40
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Andersen BM. [Misleading advertisment of pneumococcal vaccine!]. Tidsskr Nor Laegeforen 1996; 116:2355. [PMID: 8804221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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41
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Andersen BM. Biochemical profiles and serotypes of nosocomial Enterobacter cloacae strains in Northern Norway: biochemical identification problems with commercial test systems. Infection 1995; 23:339-43. [PMID: 8655203 DOI: 10.1007/bf01713562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
During a period of 2 years, 118 strains of Enterobacter cloacae were collected consecutively in connection with nosocomial infections in Northern Norway; identified by conventional methods and by the API 20E system. The API 20E profile 3305573 predominated and was present in 73 of 118 strains. Among 96 serotyped strains, 73 were serotypable, 20 nontypable and two polyagglutinable. Predominating serotypes were 3 (29 strains), 8 (21 strains) and 23 (nine strains). When the API 20E profiles of the 118 strains were read in the new ATB (automated computer-assisted) 20E data base system, 97 of 118 (82.2%) strains were identified as E. cloacae. The 118 strains were tested in the new ATB Rapid ID 32E and ATB ID 32E (ATB system, bioMérieux, France) systems. Only 69 of 118 (58.5%) strains were identified as E. cloacae in both systems. The ATB Rapid ID 32E identified 97 of 118 strains (82.2%), and the ATB ID 32E only 80 of 118 strains (67.8%). Among 73 serotypable strains, the ATB Rapid ID 32E identified 79.5% as E. cloacae, while the ATB ID 32E identified only 64.4%. Among 40 serotypable strains with API 20E profile 3305573, all 40 were identified as E. cloacae by the ATB Rapid ID 32E, while only 27 (67.5%) by the ATB ID 32E system. Further improvements may increase the value of biochemical identification of E. cloacae in diagnostic work.
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Affiliation(s)
- B M Andersen
- Dept. of Hospital Infections, Clinic for Preventive Medicine, Ullevål University Hospital, Oslo, Norway
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Christensen JB, Andersen BM, Thomassen SM, Johansen O, Lie M. The effects of 'in-use' surgical handwashing on the pre- and postoperative fingertip flora during cardiothoracic and orthopaedic surgery. J Hosp Infect 1995; 30:283-93. [PMID: 7499809 DOI: 10.1016/0195-6701(95)90263-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Two operating teams (25 persons) were followed for two months with fingerprint samples taken preoperatively; before and after 'in-use' surgical handwashing; and immediately postoperatively, with and without surgical gloves. The mean time for handwashing for the cardiothoracic team (CT) was 2 min and for the orthopaedic team (OT) was 3.5 min. A closer observation of 10 persons revealed a great individual variation in washing techniques, in spite of standard guidelines. The CT team performed eight, and the OT team nine sterile operations with an average duration of 3 h and 20 min and 2 h and 40 min, respectively. Surgical handwashing resulted in fingertip sterility in 111/118 (94.1%) cases; in 61/66 (92.4%) samples from the surgeons and in 50/52 (96.2%) samples from the assistants. Postoperative fingerprinting with gloves on showed sterile conditions in 85/91 (93.4%) samples; 57/59 (96.6%) from the surgeons and 28/32 (87.5%) from the assistants. Immediately after removal of the gloves, 43/67 (64.2%) of fingerprint samples from the surgeons and 13/48 (27.1%) from the assistants were still sterile. Coagulase-negative staphylococci (CNS) and Bacillus species predominated in fingerprint samples. Of the 105 CNS strains tested, 11.4% were methicillin resistant. Only five strains of Staphylococcus aureus were isolated; in 4/5 cases from the OT. This study illustrates that in spite of standard guidelines, there is great individual variation in surgical handwashing. However, in most instances, the bacteria are eradicated from the fingertips. Even after surgery for 2-3 h, there may still be a residual effect of the hand disinfecting agent in half of the cases.
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Affiliation(s)
- J B Christensen
- Department of Medical Microbiology, University Hospital, Tromsø, Norway
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Magnus T, Andersen BM. Serotypes and resistance patterns of Streptococcus pneumoniae causing systemic disease in northern Norway. Eur J Clin Microbiol Infect Dis 1995; 14:229-34. [PMID: 7614966 DOI: 10.1007/bf02310362] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
During the period 1985-1990, Streptococcus pneumoniae was isolated form 97 patients with systemic pneumococcal disease in Northern Norway. Systemic disease occurred most frequently in the age groups 0-4 years and > 60 years. An increasing incidence was observed, especially among children less than five years old. Serotypes covered by the 23-valent pneumococcal polysaccharide vaccine were found in 86 of 97 (88.7%) isolates. The vaccine did not cover 16.7% of the systemic isolates from children less than five years old. Reduced sensitivity to penicillin was found in one isolate (1.0%) which was resistant to ampicillin, doxycycline and chloramphenicol. The E-test and the Rosco agar diffusion test differed in sensitivity to penicillin, chloramphenicol, ciprofloxacin and erythromycin. Three serotype 12F strains showed unusual cross-resistance to chloramphenicol and erythromycin.
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Affiliation(s)
- T Magnus
- Department of Medical Microbiology, University Hospital, Tromsø, Norway
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Gauperaa T, Sundsfjord A, Andersen BM. Necrotising fasciitis and ischiorectal abscess. Eur J Surg 1995; 161:211-2. [PMID: 7599302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- T Gauperaa
- Department of Surgery, University Hospital, Tromsø, Norway
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Andersen BM, Weyant RS, Steigerwalt AG, Moss CW, Hollis DG, Weaver RE, Ashford D, Brenner DJ. Characterization of Neisseria elongata subsp. glycolytica isolates obtained from human wound specimens and blood cultures. J Clin Microbiol 1995; 33:76-8. [PMID: 7699070 PMCID: PMC227883 DOI: 10.1128/jcm.33.1.76-78.1995] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Four slightly yellow-pigmented, alpha-hemolytic, gram-negative coccobacilli, three from wound specimens and one from multiple blood cultures of a patient with endocarditis, were identified as Neisseria elongata subsp. glycolytica on the basis of their overall biochemical and genetic similarities to this subspecies. These strains resembled N. elongata in their guanine-plus-cytosine contents (55.6 to 57.1 mol%) and in their overall cellular fatty acid profiles, which are characterized by large amounts of 16:0, 16:1 omega 7c, and 18:1 omega 7c fatty acids. Their identities were confirmed by species-level DNA relatedness (hydroxyapatite method) to the type strains of all three N. elongata subspecies. The biochemical profiles and cultural characteristics of these strains resembled those of the type strain of N. elongata subsp. glycolytica except for the production of a weak yellow growth pigment and alpha-hemolysis on sheep blood agar. They differed from N elongata subsp. elongata by the production of catalase, by the production of alpha-hemolysis on sheep blood agar, and by acid production from D-glucose. They differed from N. elongata subsp. nitroreducens by the production of catalase and an inability to reduce nitrate. These studies suggest a pathogenic potential for N. elongata subsp. glycolytica, usually considered to be a transient colonizer in humans.
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Affiliation(s)
- B M Andersen
- Department of Medical Microbiology, University Hospital of Tromsø, Norway
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Andersen BM, Steigerwalt AG, O'Connor SP, Hollis DG, Weyant RS, Weaver RE, Brenner DJ. Neisseria weaveri sp. nov., formerly CDC group M-5, a gram-negative bacterium associated with dog bite wounds. J Clin Microbiol 1993; 31:2456-66. [PMID: 8408570 PMCID: PMC265778 DOI: 10.1128/jcm.31.9.2456-2466.1993] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
CDC group M-5 is a rod-shaped, gram-negative, nonmotile bacterium associated with dog bite wounds. DNA-DNA relatedness and biochemical and growth characteristics were studied for 54 strains from the collection at the Centers for Disease Control and Prevention. One typical M-5 strain, 8142, was further studied by 16S rRNA sequencing. DNA from 40 of 53 strains showed 82 to 100% relatedness (hydroxyapatite method) to labeled DNA from strain 8142. The guanine-plus-cytosine (G + C) content in 8 of the 41 highly related M-5 strains was 50.5 to 52 mol%. These 41 strains were oxidase and catalase positive, nonfermentative, nitrite positive, nitrate negative, weakly phenylalanine deaminase positive, aerobic, and alpha-hemolytic (sheep blood). DNA from the 13 remaining strains showed only 7 to 46% DNA relatedness to strain 8142. These 13 non-M-5 strains differed from the M-5 strains in G + C content, growth characteristics, and biochemical profiles. DNA from M-5 strain 8142 was most closely related to DNA from groups EF-4b (47%) and EF-4a (45%). 16S rRNA sequence analysis placed M-5 strain 8142 in the Neisseriaceae cluster of the beta-3 subgroup of the class Proteobacteria. It was most homologous (98.4 to 98.8%) to Neisseria animalis, Neisseria flavescens, Neisseria canis, and Neisseria elongata. All data are consistent with M-5 being a new species of Neisseria, for which we propose the name Neisseria weaveri.
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Affiliation(s)
- B M Andersen
- Department of Medical Microbiology, University Hospital of Tromsø, Norway
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Wium ET, Andersen BM, Flaegstad T. [Haemophilus influenzae infections in children]. Tidsskr Nor Laegeforen 1993; 113:329-33. [PMID: 8441980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Haemophilus influenzae may cause serious infections, especially in small children. During the period 1980-90, 45 children with systemic H influenzae infections were admitted to the University Clinic, Tromsø. 17 patients had epiglottitis in the same period, but are not included in this material. One of the four septicemia patients and two of the 35 children with meningitis died, giving an overall lethality of 4.8%. Five of the patients with meningitis experienced neurological sequelae (14% of the patients with meningitis). Two of the systemic isolates of H influenzae were resistant to ampicillin because of beta-lactamase production, but all the isolates were susceptible to chloramphenicol and 3rd generation cephalosporins.
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Affiliation(s)
- E T Wium
- Barneavdelingen, Regionsykehuset i Tromsø
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Schlichting E, Lyberg T, Solberg O, Andersen BM. Endotoxin liberation from Neisseria meningitidis correlates to their ability to induce procoagulant and fibrinolytic factors in human monocytes. Scand J Infect Dis 1993; 25:585-94. [PMID: 8284643 DOI: 10.3109/00365549309008547] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Endotoxin released from different strains of Neisseria meningitidis were studied for their ability to induce procoagulant (tissue factor, TF), fibrinolytic (plasminogen activator, PA) and antifibrinolytic (plasminogen activator inhibitor 2, PAI-2) factors in human monocytes. Two meningococcal strains that liberate endotoxin (E+; 270+ and 840+) and 2 non-liberating (E-; 270- and 840-) strains were used. The endotoxin activity in culture filtrates of these strains was monitored with the Limulus amoebocyte lysate (LAL) test. There was a marked difference between E+ and E- strains in their ability to liberate endotoxin. Suspensions of whole bacteria of all 4 strains induced a significant (14-19-fold) increase in monocyte TF expression when present in concentrations > 10(5) CFU/ml. At lower concentrations (10(4) CFU/ml), E+ strains were clearly more potent stimulators of TF synthesis than E- strains. Culture filtrates of E+ strains were up to 10(4)-fold more potent in inducing TF synthesis than filtrates from E- strains. This marked difference in inducing potency between E+ and E- strains was also observed when monocyte PAI-2 synthesis was examined. The PA expression, on the other hand, was suppressed when monocytes were incubated in the presence of culture filtrates, especially filtrates from the E+ strains. The increased procoagulant and antifibrinolytic activity, together with reduced profibrinolytic activity of monocytes, was closely correlated to the amount of endotoxin measured in the culture filtrates. These changes may contribute substantially to the coagulopathic state seen during systemic meningococcal disease.
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Affiliation(s)
- E Schlichting
- Department of Surgery, Ullevaal University Hospital, Oslo, Norway
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Abstract
Coagulase-negative staphylococci (CNS) of clinical significance, isolated from 131 patients, were investigated during the period 1989-90 in northern Norway. The staphylococci were isolated from blood cultures (68; 51.9%), vascular catheters (6), osteomyelitis foci (13), postoperative and other wounds (15), and urine samples (29). The use of Gram-positive Identification Card (Vitek) and 'Staph-zym' (Rosco) both gave a primarily correct species identification in 95% of the cases. Staphylococcus epidermidis was the predominant species (72.3%). Methicillin-resistance was found in 40 of 131 (30.5%) of all CNS and in 34 of 96 (35.4%) of S. epidermidis. Methicillin-resistant (MR) S. epidermidis strains were usually resistant to gentamicin, tetracycline, chloramphenicol and trimethoprim. MR strains were, however, less resistant to sulphonamides than methicillin-sensitive strains (10 out of 34 vs. 55 out of 62). Methicillin-resistance implied resistance to all beta-lactam antibiotics, including imipenem. Among S. epidermidis, MR isolates increased from 10% in 1987 to 35.4% in 1989-90. All strains were sensitive to vancomycin and rifampicin.
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Affiliation(s)
- K Refsahl
- Department of Medical Microbiology, University Hospital, Tromsø, Norway
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Andersen BM, Dahl LB, Maltau JM. [Streptococci group B and pregnancy. Need for routine check-ups?]. Tidsskr Nor Laegeforen 1992; 112:2866-8. [PMID: 1412328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Group B streptococci are a major cause of perinatal infections and affect 1-5 infants out of every 1,000 live births. Maternal vaginal colonization with these bacteria is common (5-25%), and has been associated with late abortions, foetal growth retardation, early rupture of membranes and premature delivery. Colonization with group B streptococci may be observed in more than 70% of neonates born to mothers with the bacteria in their vaginal tracts at delivery. A high number of bacteria in the maternal urogenital tract during pregnancy may predispose to early-onset disease in neonates. The estimated attack rate in colonized neonates is 1-2%. A high specific IgG antibody concentration in the mother may protect the infant, but probably not before 32 weeks of gestation. Colonized women who are unable to produce such antibodies risk having affected offspring. Neonatal infection with group B streptococci frequently results in death or permanent neurologic morbidity; especially from the early-onset type (case-fatality more than 50%) which is most often vertical transmitted. Four cases with early-onset disease illustrate the severity of perinatal group B streptococcal infections. The severity and outcome of the disease may be moderated by screening for group B streptococci during late pregnancy. This screening must be combined with special attention to irregularities in pregnancy or perinatal complications.
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Affiliation(s)
- B M Andersen
- Mikrobiologisk avdeling, Regionsykehuset i Tromsø
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