bluuebunny/crossref_metadata_2025 huggingface dataset:
Decadal cyclicity of regional mid‐Holocene precipitation: Evidence from Dominican coral proxies
Authors: Greer Lisa , Swart Peter K.
Published: June 2006

The stable carbon (δ13C) and oxygen (δ18O) isotopic compositions of four Holocene specimens of Montastraea sp. and Siderastrea sp. coral skeletons from the Dominican Republic were analyzed to examine decadal‐scale fluctuations in regional precipitation. The specimens range in length from 47 to 197 years individually and range in age from ∼7.2 to 5.2 kyr. Oscillations in the δ13C and δ18O of coral skeletons from the Holocene Enriquillo Valley occur with a seemingly consistent frequency of 15–20 years. For one coral (∼6 ka) this decadal to multidecadal mode of variability is statistically significant. The decadal to multidecadal mode of stable isotopic variability may represent cyclic fluctuations in mid‐Holocene migration of the Intertropical Convergence Zone (ITCZ) or in the hydrogeology of the region as governed by fluctuations in the passage of tropical storms and hurricanes. Regional temperature is believed to act as only a secondary control on the δ18O values of these corals. However, ITCZ migration and/or oscillations in storm frequency at this site may ultimately reflect decadal‐scale patterns in greater tropical North Atlantic sea surface temperatures. The length and resolution of climate variability represented in this study indicate a persistent decadal to multidecadal mode of Atlantic climate fluctuation throughout the mid‐Holocene that is indistinguishable from observed historical climate.
Ice sheet action versus reaction: Distinguishing between Heinrich events and Dansgaard‐Oeschger cycles in the North Atlantic
Authors: Marshall Shawn J. , Koutnik Michelle R.
Published: June 2006

Glaciers and ice sheets play an active role in the climate system and the global hydrological cycle. The stability of continental ice sheets must be better understood for assessments of future sea level rise and to uncover the causes of millennial‐scale climate variability that characterized the last glacial period. Ice‐rafted debris (IRD) in the midlatitude oceans and subpolar seas tells of widespread calving of icebergs from the Northern Hemisphere ice sheets during the last glacial period, but the climatic implications of this IRD are unclear. Does the sediment record indicate repeated dynamical collapse of the ice sheets, with ice sheets actively forcing the climate system? Alternatively, were ice sheet margins simply advancing and retreating in response to climate vacillations? On the basis of simulations of iceberg delivery to the ocean during the last glacial cycle we argue that the marine record exemplifies both of these phenomena. Heinrich events were clearly episodes of internal dynamical instability of the Laurentide Ice Sheet, while millennial‐scale IRD is more simply interpreted as a response of the circum‐Atlantic ice sheets to Dansgaard‐Oeschger climate cycles. Ice sheets in different coastal regions respond differently to climate fluctuations, but overall iceberg fluxes increase in cold periods, peaking within a few centuries of climatic cooling. Regions with relatively warm, wet climates (Scandinavia, western North America, and Svalbard) are the most sensitive to millennial climate variability, with rapid response times and large millennial variability in iceberg fluxes.
Near 5‐day nonisostatic response of the Atlantic Ocean to atmospheric surface pressure deduced from sub‐surface and bottom pressure measurements
Authors: Park Jae‐Hun , Watts D. Randolph
Published: June 2006

Nonisostatic ocean responses to atmospheric pressure have been observed in tropical regions of the Pacific and Atlantic Oceans at periods near 5 days. Barotropic ocean model simulations coupled to atmospheric forcing predicted that this nonisostatic ocean response is driven not regionally but globally by the Rossby‐Haurwitz wave. To date little observational evidence has been provided to support the model simulations, especially at extratropical latitudes. Here we present the basin‐scale nature of the nonisostatic response in the Atlantic Ocean near 5‐day periods using four historical long‐term (≥1.5 year) sub‐surface and bottom pressure measurements spanning from 16°S to 37°N. Joint analysis of them together with global‐gridded atmospheric pressure reveals a basin‐scale nonisostatic sea level fluctuation in the North and tropical Atlantic Oceans near 5‐day periods with almost uniform phase. It also confirms that the driving force for this near 5‐day fluctuation is the westward propagating Rossby‐Haurwitz wave.
Investigating the impact of remotely sensed precipitation and hydrologic model uncertainties on the ensemble streamflow forecasting
Authors: Moradkhani Hamid , Hsu K. , Hong Y. , Sorooshian S.
Published: June 2006

In the past few years sequential data assimilation (SDA) methods have emerged as the best possible method at hand to properly treat all sources of error in hydrological modeling. However, very few studies have actually implemented SDA methods using realistic input error models for precipitation. In this study we use particle filtering as a SDA method to propagate input errors through a conceptual hydrologic model and quantify the state, parameter and streamflow uncertainties. Recent progress in satellite‐based precipitation observation techniques offers an attractive option for considering spatiotemporal variation of precipitation. Therefore, we use the PERSIANN‐CCS precipitation product to propagate input errors through our hydrologic model. Some uncertainty scenarios are set up to incorporate and investigate the impact of the individual uncertainty sources from precipitation, parameters and also combined error sources on the hydrologic response. Also probabilistic measures are used to quantify the quality of ensemble prediction.
Theoretical and Experimental Optimization of Laser Speckle Contrast Imaging for High Specificity to Brain Microcirculation
Authors: Wang Zheng , Hughes Sarah , Dayasundara Sudath , Menon Ravi S
Published: June 2006

The functional spatial resolution in most of hemodynamics-based functional neuroimaging techniques is limited by the fineness of hemodynamic control with the active vascular beds likely at submillimeter resolution. This study was designed to visualize changes of cerebral blood flow (CBF) at submillimeter spatial scale on the prolonged isoflurane-anesthetized rats model by using laser speckle contrast imaging (LSCI) technique. Recently, this old method has attracted an increasing interest in studies of brain activities under normal and pathophysiologic conditions. However, some paramount assumptions behind this imaging technique have been kept ignored in this field since 1981 firstly proposed by Fercher and Briers. Most recently, these assumptions are claimed as serious mistakes that made LSCI fail to reproducibly and correctly measure blood flow speed. In our study, these issues are also re-examined theoretically and re-evaluated experimentally based on the results from the classical carbon dioxide challenge model. The detailed distribution of CBF responses to the stimulation induced by different levels of carbon dioxide pressure was obtained with tens of micron spatial resolution. The relative CBF images over the exposed cortical area acquired by LSCI were also compared with laser-Doppler measurements. Our results show that these assumptions would not produce any significant errors on investigating changes of blood flow and also achieve high specificity to assess cerebral microcirculation, as would facilitate its broad application in functional imaging field.
Abnormal Metabolic Network Activity in Parkinson'S Disease: Test—Retest Reproducibility
Authors: Ma Yilong , Tang Chengke , Spetsieris Phoebe G , Dhawan Vijay , Eidelberg David
Published: June 2006

Parkinson's disease (PD) is associated with an abnormal pattern of regional brain function. The expression of this PD-related covariance pattern (PDRP) has been used to assess disease progression and the response to treatment. In this study, we validated the PDRP network as a measure of parkinsonism by prospectively computing its expression (PDRP scores) in 15O-water (H215O) and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) scans from PD patients and healthy volunteers. The reliability of this measure was also assessed within subjects using a test—retest design in mildly affected and advanced PD patients scanned at baseline and during treatment with levodopa or deep brain stimulation (DBS). We found that PDRP expression was significantly elevated in PD patients ( P<0.001) relative to controls in a prospective analysis of brain scans obtained with either H215O or FDG PET. A significant correlation ( R2=0.61; P<0.001) was evident between PDRP scores computed from H215O and FDG images in PD subjects scanned with both tracers. Test—retest reproducibility was very high (intraclass correlation coefficient (ICC)>0.92) for PDRP scores measured both within PET session and between sessions separated by up to 2 months. This high reproducibility was observed in both early stage and advanced PD patients scanned at baseline and during treatment. The within-subject variability of this measure was less than 10% for both unmedicated and treated conditions. These findings suggest that the PDRP network is a reproducible and stable descriptor of regional functional abnormalities in parkinsonism. The quantification of PDRP expression in PD patients can serve as a potential biomarker in PET intervention studies for this disorder.
Reduced Cerebral Blood Flow but Elevated Cerebral Glucose Metabolic Rate in Erythropoietin Overexpressing Transgenic Mice with Excessive Erythrocytosis
Authors: Frietsch Thomas , Maurer Martin H , Vogel Johannes , Gassmann Max , Kuschinsky Wolfgang , Waschke Klaus F
Published: June 2006

To examine the impact of excessive erythrocytosis on local cerebral blood flow (CBF) and cerebral glucose metabolic rate (CMRglc), we made use of our constitutively erythropoietin (Epo)-overexpressing transgenic mouse line (tg-6) that reach a mean hematocrit of 0.87. Compared with wild-type (wt) control siblings, CBF decreased by 44% in tg-6 mice, while upon hemodilution (tg-6-HD) to a physiologic hematocrit (e.g., 0.44) tg-6-HD mice returned the CBF to wt levels. Cerebral blood flow was determined in another transgenic mouse line that overexpresses human Epo in the brain only (tg-21): CBF increased by 17% compared with wt controls. However, oxygen delivery was similar in all four mouse groups tested (wt, tg-6, tg-6-HD and tg-21). Mean CMRglc was higher in tg-6 (+72%), tg-6-HD mice (+43%) and tg-21 (+22%) than in wt mice. Local CMRglc was higher in all 40 brain regions in tg-6 but only in 15 and 8 regions in tg-6-HD and tg-21 mice. These results show that prolonged increases in hematocrit did not alter cerebral oxygen delivery at a decreased CBF and increased CMRglc. Hemodilution suggests that high blood viscosity is a cause of the decrease in CBF and partly of the increase in CMRglc. Cerebral glucose metabolic rate may also be increased by a direct effect of Epo in the brain (tg-21 mice).
Control Devolution as Information Infrastructure Design Strategy: A Case Study of a Content Service Platform for Mobile Phones in Norway
Authors: Nielsen Petter , Aanestad Margunn
Published: June 2006

This paper depicts the results of an empirical case study on how two Norwegian telecommunications operators developed a business sector information infrastructure for the provision of mobile content services. Focusing on the context of this technology's development, and the strategic issues behind its design, implementation and operation, control devolution as a design strategy is explored. This analysis draws on insights presented by Claudio Ciborra's in his study of the change from alignment to loose coupling in the Swiss multinational Hoffmann-La Roche. This paper illustrates how control is played out on different levels, and balanced against autonomy. The theoretical implications of this paper highlight how the differences and transformations between information systems and information infrastructures are conceptualised, with the development of the latter better understood in light of a balance between control and autonomy. Consequently, it is suggested that control devolution as a design approach should be based on a deep understanding of the existing control/autonomy balance as well as the distribution of resources, risks and the ability and willingness to innovate.
The C2H2 zinc-finger protein SYD-9 is a putative posttranscriptional regulator for synaptic transmission
Authors: Wang Ying , Gracheva Elena O. , Richmond Janet , Kawano Taizo , Couto Jillian M. , Calarco John A. , Vijayaratnam Vijhee , Jin Yishi , Zhen Mei
Published: June 2006

Communication between neurons is largely achieved through chemical synapses, where neurotransmitters are released from synaptic vesicles at presynaptic terminals to activate postsynaptic cells. Exo- and endocytosis are coordinated to replenish the synaptic vesicle pool for sustained neuronal activity. We identified
syd-9
(syd, synapse defective), a gene that encodes multiple C2H2 zinc-finger domain-containing proteins specifically required for synaptic function in
Caenorhabditis elegans
.
syd-9
loss-of-function mutants exhibit locomotory defects, a diffuse distribution of synaptic proteins, and decreased synaptic transmission with unaffected neurodevelopment.
syd-9
mutants share phenotypic and ultrastructural characteristics with mutants that lack synaptic proteins that are required for endocytosis.
syd-9
mutants also display genetic interactions with these endocytotic mutants, suggesting that SYD-9 regulates endocytosis. SYD-9 proteins are enriched in the nuclei of both neuron and muscle cells, but their neuronal expression plays a major role in locomotion. SYD-9 isoforms display a speckle-like expression pattern that is typical of RNA-binding proteins that regulate premRNA splicing. Furthermore,
syd-9
functions in parallel with
unc-75
(unc, uncoordinated), the
C. elegans
homologue of the CELF/BrunoL family protein that regulates mRNA alternative splicing and processing, and is also required specifically for synaptic transmission. We propose that neuronal SYD-9 proteins are previously uncharacterized and specific posttranscriptional regulators of synaptic vesicle endocytosis.
Primary processes underlying the photostability of isolated DNA bases: Adenine
Authors: Satzger Helmut , Townsend Dave , Zgierski Marek Z. , Patchkovskii Serguei , Ullrich Susanne , Stolow Albert
Published: June 2006

The UV chromophores in DNA are the nucleic bases themselves, and it is their photophysics and photochemistry that govern the intrinsic photostability of DNA. Because stability is related to the conversion of dangerous electronic to less-dangerous vibrational energy, we study ultrafast electronic relaxation processes in the DNA base adenine. We excite adenine, isolated in a molecular beam, to its ππ* state and follow its relaxation dynamics using femtosecond time-resolved photoelectron spectroscopy. To discern which processes are important on which timescales, we compare adenine with 9-methyl adenine. Methylation blocks the site of the much-discussed πσ* state that had been thought, until now, minor. Time-resolved photoelectron spectroscopy reveals that, although adenine and 9-methyl adenine show almost identical timescales for the processes involved, the decay pathways are quite different. Importantly, we confirm that in adenine at 267-nm excitation, the πσ* state plays a major role. We discuss these results in the context of recent experimental and theoretical studies on adenine, proposing a model that accounts for all known results, and consider the relationship between these studies and electron-induced damage in DNA.
Variants in the SP110 gene are associated with genetic susceptibility to tuberculosis in West Africa
Authors: Tosh Kerrie , Campbell Sarah J. , Fielding Katherine , Sillah Jackson , Bah Boubacar , Gustafson Per , Manneh Kebba , Lisse Ida , Sirugo Giorgio , Bennett Steve , Aaby Peter , McAdam Keith P. W. J. , Bah-Sow Oumou , Lienhardt Christian , Kramnik Igor , Hill Adrian V. S.
Published: June 2006

The
sst1
locus has been identified in a mouse model to control resistance and susceptibility of
Mycobacterium tuberculosis
infection. Subsequent studies have now identified
Ipr1
(intracellular pathogen resistance 1) to be the gene responsible.
Ipr1
is encoded within the
sst1
locus and is expressed in the tuberculosis lung lesions and macrophages of
sst1
-resistant, but not
sst1
-susceptible mice. We have therefore examined the closest human homologue of
Ipr1
, SP110, for its ability to control susceptibility to
M. tuberculosis
infection in humans. In a study of families from The Gambia we have identified three polymorphisms that are associated with disease. On examination of additional families from Guinea-Bissau and the Republic of Guinea, two of these associations were independently replicated. These variants are in strong linkage disequilibrium with each other and lie within a 31-kb block of low haplotypic diversity, suggesting that a polymorphism within this region has a role in genetic susceptibility to tuberculosis in humans.
The magnitude of bias in a cross-sectional study on lifestyle factors in relation to Type 2 diabetes
Authors: Agardh Emilie E. , Ahlbom Anders , Andersson Tomas , Östenson Claes-Göran
Published: June 2006

Aim: In cross-sectional studies it may be difficult to ascertain the temporal order of exposure and disease, which may have consequences for causal inference. The authors aimed to illustrate the possible magnitude of this potential bias using data from a cross-sectional study on coffee consumption and work stress in relation to type 2 diabetes. Methods: By a series of computer simulations the authors examined to what extent the observed negative association between type 2 diabetes and high coffee consumption and positive association between type 2 diabetes and high work stress could be due to reverse causality, by assuming that cases changed their exposures in response to development of the disease. Results: If the negative association between coffee and type 2 diabetes was a consequence of reversed causality, 30—40% of the cases would have to decrease their coffee consumption from≥5 cups of coffee per day to 3—4 cups per day and from 3—4 cups per day to≤2 cups of coffee per day. Moreover, approximately 60% of the cases would have to increase their work stress from low to medium work stress and from medium to high work stress, in order to produce the positive association with diabetes that was observed. Conclusion: Even if the type 2 diabetic patients to some extent may have changed their exposure in response to disease development, it seems unlikely that the associations observed between type 2 diabetes, coffee consumption, and work stress are due to this bias.
Antibiotic-Stewardship Practices at Top Academic Centers Throughout the United States and at Hospitals Throughout Massachusetts
Authors: Barlam Tamar F. , DiVall Margarita
Published: June 2006

Objective.

Improvements in antibiotic prescribing to reduce bacterial resistance and control hospital costs is a growing priority, but the way to accomplish this is poorly defined. Our goal was to determine whether certain antibiotic stewardship interventions were universally instituted and accepted at top US academic centers and to document what interventions, if any, are used at both teaching and community hospitals within a geographic area.

Design.

Two surveys were conducted. In survey 1, detailed phone interviews were performed with the directors of antibiotic stewardship programs at 22 academic medical centers that are considered among the best for overall medical care in the United States or as leaders in antibiotic stewardship programs. In survey 2, teaching and community hospitals throughout Massachusetts were surveyed to ascertain what antibiotic oversight program components were present.

Results.

In survey 1, each of the 22 participating hospitals had instituted interventions to improve antibiotic prescribing, but none of the interventions were universally accepted as essential or effective. In survey 2, of 97 surveys that were mailed to prospective participants, a total of 54 surveys from 19 teaching hospitals and 35 community hospitals were returned. Ninety-five percent of the teaching hospitals had a restricted formulary, compared with 49% of the community hospitals, and 89% of teaching hospitals had an antibiotic approval process, compared with 29% of community hospitals.

Conclusion.

There was great variability among the approaches to the oversight of antibiotic prescribing at major academic hospitals. Antibiotic management interventions were lacking in more than half of the Massachusetts community hospitals surveyed. More research is needed to define the best antibiotic stewardship interventions for different hospital settings.
Comparison of UV C Light and Chemicals for Disinfection of Surfaces in Hospital Isolation Units
Authors: Andersen B. M. , Bånrud H. , Bøe E. , Bjordal O. , Drangsholt F.
Published: June 2006

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.
Correlation Between Legionella Contamination in Water and Surrounding Air
Authors: Crimi Paolo , Macrina Gianni , Grieco Antonio , Tinteri Carola , Copello Laura , Rebora Daniela , Galli Angelo , Rizzetto Rolando
Published: June 2006

We evaluated Legionella pneumophila contamination of water and surrounding air in a burn care department equipped with bathtubs. In water, the bacterium always aerosolized, but in surrounding air, it diluted itself to such a point that it became undetectable at 1 m or more from the source of emission, which indicated that patients were at low risk of inhaling a dangerous quantity of the microbe.
Pseudomonas aeruginosaSepsis in Stem Cell Transplantation Patients
Authors: Fanci Rosa , Pecile Patrizia , Casalone Enrico , Mengoni Alessio , Tamburini Elena , Guidi Stefano , Cecconi Daniela , Bosi Alberto , Nicoletti Pierluigi , Mastromei Giorgio
Published: June 2006

We report the epidemiological investigation of an outbreak ofPseudomonas aeruginosainfection in 6 patients who shared, during different periods, the same 2 rooms of a bone marrow transplantation unit. Phenotypic and molecular analysis of isolates from patients and from the environment strongly suggested a single, environmental source of infection.
3-Methyl-4-Chlorophenol for Prion Decontamination of Medical Devices
Authors: Riemer Constanze , Bamme Theresa , Mok Simon Wing Fai , Baier Michael
Published: June 2006

Disinfectants containing 3-methyl-4-chlorophenol were tested for their capacity to inactivate the infectious agent of scrapie. Coincubation of brain homogenates prepared from terminally ill scrapie-infected hamsters with the disinfectants rendered the prion protein PrPSc sensitive to proteinase K digestion. Inoculation of hamsters with disinfectant-treated samples indicated a reduction in infectivity levels to below the limit of detection.
Patterns in the Offering of Hepatitis B Prophylaxis by US Emergency Department Physicians
Authors: Merchant Roland C. , Keshavarz Reza
Published: June 2006

US emergency department physicians surveyed were more likely to offer hepatitis B prophylaxis to patients after unknown hepatitis B status needlestick injuries than sexual exposures, especially consensual sex. There was no difference in willingness to offer prophylaxis with respect to patient occupation or age or with respect to ED physicians' demographic and professional characteristics.
Polymerase Chain Reaction Identification of Coagulase-Negative Staphylococci and of Strain Diversity and Spread of Staphylococcus epidermidis in a Major Medical Center in Lebanon
Authors: Abdallah Inaya M. , Araj George E , Matar Ghassan M. , Abdelnour George , Uwaydah Marwan , Abdelnoor Alexander M.
Published: June 2006

A 2-step polymerase chain reaction (PCR) assay and random amplification of polymorphic DNA (RAPD) analysis, respectively, were assessed to identify coagulase-negative staphylococci organisms to the species level and to determine the strain diversity and spread of Staphylococcus epidermidis, the most frequently isolated species, in a medical center in Beirut, Lebanon. Our data indicated that PCR was faster and was more efficient in identifying S. epidermidis isolates than is conventional biochemical testing. RAPD analysis have shown that S. epidermidis strains were scattered across the different clinical services, demonstrating various clusters of infection in the medical center.
The Importance of Addressing Multidrug Resistance and Not Assuming Single-Drug Resistance in Case-Control Studies
Authors: D'Agata Erika M. C. , Cataldo Maria Adriana , Cauda Roberto , Tacconelli Evelina
Published: June 2006

Background.

Case-control studies analyzing antibiotic exposure as a risk factor for antimicrobial resistance usually assume single-drug resistance in the bacteria under study, even though resistance to multiple antimicrobials may be present. Since antibiotic selection pressures differ depending on the susceptibility profile of the antimicrobial-resistant bacteria, an accurate assessment of whether exposure to an individual antimicrobial is a risk factor for the emergence of resistance should distinguish between single-drug–resistant and multidrug-resistant bacteria.

Objective.

To determine whether the exposures to individual antibiotics that were identified as independent risk factors in case-control studies differed depending on whether single-drug–resistant or multidrug-resistant bacteria were evaluated.

Design.

Two retrospective case-control studies were performed with data on patients harboringPseudomonas aeruginosastrains resistant only to ciprofloxacin (CRPA) and patients harboringP. aeruginosastrains resistant to ciprofloxacin and other antibiotics (multidrug-resistantP. aeruginosa[MDR-PA]). These 2 groups were compared with patients not harboringP. aeruginosa.

Setting.

Two tertiary care hospitals.

Results.

A total of 41 patients harboring CRPA and 151 patients harboring MDR-PA were identified and matched to 192 control subjects. By conditional logistic regression, independent risk factors associated with presence of CRPA were nonambulatory status (OR, 5.6 [95% confidence interval {CI}, 1.4-23];P= .02) and prior ciprofloxacin exposure (OR, 5.0 [95% CI, 1.2-21];P= .03). Independent risk factors for presence of MDR-PA were a Charlson score greater than 2 (OR, 3.3 [95% CI 1.8-6.0];P<.001) and exposure to quinolones (OR, 2.8 [95% CI, 1.2-5.0];P= .001), third- and fourth-generation cephalosporins (OR, 3.5 [95% CI, 1.7-7.1];P<.001), imipenem (OR, 3.8 [95% CI, 1.2-12.1];P= .02), and/or aminoglycosides (OR, 2.3 [95% CI, 1.04-5.1];P= .04).

Conclusion.

There were substantial differences in exposure to individual antimicrobials between patients harboring CRPA and patients harboring MDR-PA. Future case-control studies addressing risk factors for single-drug–resistant bacteria should consider the complete susceptibility profile of the bacteria under investigation.
Inaccurate Communications in Telephone Calls to an Antimicrobial Stewardship Program
Authors: Linkin Darren R. , Paris Sarah , Fishman Neil O. , Metlay Joshua P. , Lautenbach Ebbing
Published: June 2006

Background.

Antimicrobial stewardship programs (ASPs) decrease unnecessary antimicrobial use, decrease antimicrobial resistance, and improve patient outcomes. The effectiveness of a prior approval system—that is, the requirement that approval be obtained from ASP practitioners before certain antimicrobials can be used—depends on the accuracy of the patient data communicated from the primary service.

Objectives.

To determine the incidence of inaccurate communication of patient data during ASP interactions, describe examples of inaccurate communications, and identify risk factors for inaccurate communication.

Design.

We used a retrospective cohort design. We evaluated the communicated patient data for clinically important inaccuracies, using the patients' medical records as the gold standard.

Setting.

A tertiary care medical center that has a prior approval system for restricted antimicrobials.

Patients.

Inpatients discussed in telephone ASP interactions.

Intervention.

Observational study.

Results.

Of telephone calls requesting prior approval from ASP practitioners, 39% (95% confidence interval [CI], 31%-48%) contained an inaccuracy in at least 1 type of patient data (eg, current antimicrobial therapy); the incidence varied widely between data types. Examples of inaccuracies are given to demonstrate their clinical relevance. In multivariable analysis, inaccurate communications were more common for telephone calls from surgical services (versus calls from nonsurgical services: odds ratio, 2.1 [95% CI, 1.1-3.9]) and for calls received by Infectious Diseases fellows (versus pharmacists: odds ratio, 2.0 [95% CI, 1.1-3.8]).

Conclusions.

A high proportion of ASP calls requesting prior approval included patient data inaccuracies, which have the potential to affect the prescribing of antimicrobials. Although risk factors were identified, these communication errors were common across the different types of ASP interactions. Inaccurate communications may compromise the utility of ASPs that use a prior approval system for optimizing antimicrobial use.
Acquisition of Multidrug-Resistant Organisms Among Hospital Patients Hospitalized in Beds Adjacent to Critically Ill Patients
Authors: Cohen Matan J. , Anshelevich Olga , Raveh David , Broide Ellen , Rudensky Bernard , Yinnon Amos M.
Published: June 2006

Objective.

To assess whether patients hospitalized in beds physically adjacent to critically ill patients are at increased risk to acquire multidrug-resistant pathogens.

Design.

Cohort study.

Setting.

Shaare Zedek Medical Center, a 550-bed medical referral center.

Patients.

From April to September 2004, we enrolled consecutive newly admitted patients who were hospitalized in beds adjacent to either mechanically ventilated patients or patients designated as “do not resuscitate” (DNR). For each of these patients, we also enrolled a control patient who was not hospitalized in a bed adjacent to a critically ill patient. We collected specimens from the anterior nares, the oral cavity, and the perianal zone at the time of admission and subsequently at 3-day intervals until discharge or death. Specimens were cultured on selective media to detect growth of antibiotic-resistant pathogens, includingAcinetobacter baumannii, methicillin-resistantStaphylococcus aureus(MRSA), extended-spectrum β lactamase (ESBL)–producing Enterobacteriaceae, and vancomycin-resistant enterococci (VRE).

Results.

We enrolled 46 neighbor-control pairs. Among neighbors and controls, respectively, the incidence rates for isolation ofA. baumanniiwas 8.3 and 4 isolations per 100 patient-days (relative risk [RR], 2.1 [95% confidence interval {CI}, 0.8-5.2];P= .12), the incidence rates for MRSA were 1.4 and 2.6 isolations per 100 patient-days (RR, 0.6 [95% CI, 0.1-2.3];P= .45), the incidence rates for ESBL-producing Enterobacteriaceae were 10.5 and 9 isolations per 100 patient-days (RR, 1.2 [95% CI, 0.6-2.4];P= .84), the incidence rates for VRE were 4.3 and 4.8 isolations per 100 patient-days (RR, 0.9 [95% CI, 0.3-2.4];P= 1), and the composite incidence rate was 21.7 and 16.2 isolations per 100 patient-days (RR, 1.3 [95% CI, 0.8-2.3];P= 0.3).

Conclusions.

In this pilot study, we did not detect an increased incidence rate of isolation of multidrug-resistant pathogens among patients hospitalized in beds adjacent to critically ill patients. Further studies with larger samples should be conducted in order to generate valid data and provide patients, physicians, and policy makers with a sufficient knowledge base from which decisions can be made.
A Web-Based Course on Infection Control for Physicians in Training An Educational Intervention
Authors: Fakih Mohamad G. , Enayet Iram , Minnick Steven , Saravolatz Louis D.
Published: June 2006

Objective.

To evaluate the effectiveness of a Web-based course on infection control accessed by physicians in training.

Design.

Educational intervention.

Setting.

A 607-bed urban teaching hospital.

Participants.

A total of 55 physicians in training beginning their first postgraduate year (the iPGYl group) and 59 physicians completing their first, second, or third postgraduate year (the oPGY group).

Intervention.

Individuals in the iPGYl group took a Web-based course on infection control practices.

Measurements.

Persons in the iPGYl group who took the Web-based course completed an evaluation test consisting of 15 multiple-choice questions (total possible score, 15 points). The same test was given to persons in the oPGY group, who did not take the Web-based course. We compared scores of the Web-based test taken by subjects in the iPGYl group immediately after the course with scores of the test they took 3 months after the course and with test scores of subjects in the oPGY group.

Results.

The mean score (±SD) for subjects in the iPGYl group who took the Web-based course was 10.6 ± 2.2, compared with 8.0 ± 2.5 for subjects in the oPGY group (P<.001). The mean score (±SD) for subjects in the iPGYl group 3 months after completing the course decreased to 8.0 ± 2.4 (P< .001 by the paired f test). For the oPGY group, significant differences were found between the scores (±SD) for subjects in the internal medicine (9.9 ± 2.3), emergency medicine (8.4 ± 1.7), pediatrics (7.0 ± 1.7), and family medicine (5.8 ± 1.6) residency programs (P< .001); there were no significant differences in scores according to the year of residency.

Conclusions.

Web-based infection control courses are an attractive teaching tool for physicians in training and need to be considered for teaching infection control. The evaluation of information retention will help identify physicians in training who require further training.
A Multicenter Intervention to Prevent Catheter-Associated Bloodstream Infections
Authors: Warren David K. , Cosgrove Sara E. , Diekema Daniel J. , Zuccotti Gianna , Climo Michael W. , Bolon Maureen K. , Tokars Jerome I. , Noskin Gary A. , Wong Edward S. , Sepkowitz Kent A. , Herwaldt Loreen A. , Perl Trish M. , Solomon Steven L. , Fraser Victoria J.
Published: June 2006

Background.

Education-based interventions can reduce the incidence of catheter-associated bloodstream infection. The generalizability of findings from single-center studies is limited.

Objective.

To assess the effect of a multicenter intervention to prevent catheter-associated bloodstream infections.

Design.

An observational study with a planned intervention.

Setting.

Twelve intensive care units and 1 bone marrow transplantation unit at 6 academic medical centers.

Patients.

Patients admitted during the study period.

Intervention.

Updates of written policies, distribution of a 9-page self-study module with accompanying pretest and posttest, didactic lectures, and incorporation into practice of evidence-based guidelines regarding central venous catheter (CVC) insertion and care.

Measurements.

Standard data collection tools and definitions were used to measure the process of care (ie, the proportion of non-tunneled catheters inserted into the femoral vein and the condition of the CVC insertion site dressing for both tunneled and nontunneled catheters) and the incidence of catheter-associated bloodstream infection.

Results.

Between the preintervention period and the postintervention period, the percentage of CVCs inserted into the femoral vein decreased from 12.9% to 9.4% (relative ratio, 0.73; 95% confidence interval [CI], 0.61-0.88); the total proportion of catheter insertion site dressings properly dated increased from 26.6% to 34.4% (relative ratio, 1.29; 95% CI, 1.17-1.42), and the overall rate of catheter-associated bloodstream infections decreased from 11.2 to 8.9 infections per 1,000 catheter-days (relative rate, 0.79; 95% CI, 0.67-0.93). The effect of the intervention varied among individual units.

Conclusions.

An education-based intervention that uses evidence-based practices can be successfully implemented in a diverse group of medical and surgical units and reduce catheter-associated bloodstream infection rates.
AcinetobacterSkin Colonization of US Army Soldiers
Authors: Griffith Matthew E. , Ceremuga Julia M. , Ellis Michael W. , Guymon Charles H. , Hospenthal Duane R. , Murray Clinton K.
Published: June 2006

Objective.

To evaluate whether skin colonization withAcinetobacter calcoaceticus-baumanniicomplex exists in a population of healthy, nondeployed US Army soldiers and, if present, how it might relate to the infections seen in current war casualties.

Design.

We sampled various skin sites of soldiers to test for the presence ofA. calcoaceticus-baumanniicomplex and to establish the prevalence of colonization. We then used ribotyping and antimicrobial susceptibility profiles to compare the isolates we recovered withA. calcoaceticus-baumanniicomplex isolates from injured soldiers.

Setting.

Fort Sam Houston, Texas.

Participants.

A population of healthy, nondeployed US Army soldiers in training.

Results.

A total of 17% of healthy soldiers were found to harborA. calcoaceticus-baumanniicomplex. However, the strains differed from those recovered from injured soldiers.

Conclusions.

Skin carriage ofA. calcoaceticus-baumanniicomplex exists among soldiers before deployment. However, the difference in the strains isolated from healthy soldiers, compared with the strains from injured soldiers, makes it difficult to identify skin colonization as the source of infection.
Control of an Outbreak of Multidrug-ResistantAcinetobacter baumannii-calcoaceticusColonization and Infection in an Intensive Care Unit (ICU) Without Closing the ICU or Placing Patients in Isolation
Authors: Wilks Mark , Wilson Anne , Warwick Simon , Price Elizabeth , Kennedy Daniel , Ely Andrew , Millar Michael R.
Published: June 2006

Objective.

To describe the control of multidrug-resistantAcinetobacter baumannii-calcoaceticus(MDRABC) colonization and infection in an intensive care unit (ICU).

Setting.

An 18-bed ICU in a large tertiary care teaching hospital in London.

Interventions.

After recognition of the outbreak, a range of infection control measures were introduced over several months that were primarily aimed at reducing environmental contamination with the outbreak strain. Strategies included use of a closed tracheal suction system for all patients receiving mechanical ventilation, use of nebulized colistin for patients with evidence of mild to moderate ventilator-associated pneumonia, improved availability of alcohol for hand decontamination, and clearer designation of responsibilities and strategies for cleaning equipment and the environment in the proximity of patients colonized or infected with MDRABC.

Results.

The outbreak lasted from June 2001 through November 2002 and involved 136 new cases of MDRABC infection or colonization. The number of newly diagnosed cases per month reached a maximum of 15 in February 2002, and the number of new cases slowly decreased over the next 9 months.

Conclusion.

This outbreak was controlled by emphasizing the control of environmental reservoirs and did not require recourse to ward closure or placement of affected patients in isolation.
Emergence of Carbapenem Resistance inAcinetobacter baumanniiRecovered From Blood Cultures in Australia
Authors: Peleg Anton Y. , Franklin Clare , Bell Jan M. , Spelman Denis W.
Published: June 2006

We describe the first emergence of carbapenem-resistantAcinetobacter baumanniiin Australia. NinetyA. baumanniiisolates recovered from cultures of blood specimens from 69 patients were analyzed. Overall, 58 isolates (64%) were resistant to meropenem. The χ2test for linear trend revealed that emergence of carbapenem resistance was statistically significant during the 32-month study period. Selected isolates were of the same clonal type, and no genes encoding carbapenemases were identified.
Retrospective Analysis of Multidrug-ResistantAcinetobacter baumanniiStrains Isolated During a 4-Year Period in a University Hospital
Authors: Fillaux Judith , Dubouix Anne , Conil Jean-Marie , Laguerre Jacky , Marty Nicole
Published: June 2006

Objective.

To describe the epidemiology ofAcinetobacter baumanniiinfection during 2000-2003 and to determine whether the multidrug-resistant strains were already present in our Toulouse hospital before the 2003 French national outbreak.

Design.

Descriptive molecular and clinical epidemiologic study ofA. baumanniiisolates using a combination of antibiotyping and pulsed-field gel electrophoresis (PFGE).

Setting.

A 1,000-bed university hospital in Toulouse, France.

Methods.

All clinical samples that had tested positive forA. baumanniibetween January 1, 2000, and December 31, 2003, were collected. Multidrug-resistant isolates ofA. baumanniiwere then submitted to PFGE, and clinical characteristics of the source patients were noted.

Results.

A total of 1,277A. baumanniisamples were identified, 791 of which had not been previously identified; 148 were positive for multidrug-resistant strains. These strains were more likely to have been isolated in the intensive care unit (ICU) than were susceptible strains (P<.001; relative hazard, 3.77). The positive clinical samples were of various types (eg, nonprotected respiratory samples [43%] and blood [5%]), but no difference in type of source was seen between resistant and susceptible strains. A simultaneous analysis of pulsotypes and antibiotypes proved that the outbreak in the ICU in 2003 could be linked to an initially endemic clone that had been isolated in 2001. Furthermore, a second clone responsible for an extended-spectrum β-lactamase phenotype was sporadically present in our institution. Although the strains isolated in the burn unit were also genetically related one to another, the specific responsible clone only appeared in 2003.

Conclusion.

Several multidrug-resistant clones can coexist endemically for several years and can be detected during an outbreak by close survey of epidemic sources.
Random Coefficient Models for Time-Series—Cross-Section Data: Monte Carlo Experiments
Authors: Beck Nathaniel , Katz Jonathan N.
Published: June 2006

This article considers random coefficient models (RCMs) for time-series—cross-section data. These models allow for unit to unit variation in the model parameters. The heart of the article compares the finite sample properties of the fully pooled estimator, the unit by unit (unpooled) estimator, and the (maximum likelihood) RCM estimator. The maximum likelihood estimator RCM performs well, even where the data were generated so that the RCM would be problematic. In an appendix, we show that the most common feasible generalized least squares estimator of the RCM models is always inferior to the maximum likelihood estimator, and in smaller samples dramatically so.
Intraoperative Tidal Volume as a Risk Factor for Respiratory Failure after Pneumonectomy
Authors: Fernández-Pérez Evans R. , Keegan Mark T. , Brown Daniel R. , Hubmayr Rolf D. , Gajic Ognjen
Published: June 2006

Background

Respiratory failure is a leading cause of postoperative morbidity and mortality in patients undergoing pneumonectomy. The authors hypothesized that intraoperative mechanical ventilation with large tidal volumes (VTs) would be associated with increased risk of postpneumonectomy respiratory failure.

Methods

Patients undergoing elective pneumonectomy at the authors' institution from January 1999 to January 2003 were studied. The authors collected data on demographics, relevant comorbidities, neoadjuvant therapy, pulmonary function tests, site and type of operation, duration of surgery, intraoperative ventilator settings, and intraoperative fluid administration. The primary outcome measure was postoperative respiratory failure, defined as the need for continuation of mechanical ventilation for greater than 48 h postoperatively or the need for reinstitution of mechanical ventilation after extubation.

Results

Of 170 pneumonectomy patients who met inclusion criteria, 30 (18%) developed postoperative respiratory failure. Causes of postoperative respiratory failure were acute lung injury in 50% (n = 15), cardiogenic pulmonary edema in 17% (n = 5), pneumonia in 23% (n = 7), bronchopleural fistula in 7% (n = 2), and pulmonary thromboembolism in 3% (n = 1). Patients who developed respiratory failure were ventilated with larger intraoperative VT than those who did not (median, 8.3 vs. 6.7 ml/kg predicted body weight; P < 0.001). In a multivariate regression analysis, larger intraoperative VT (odds ratio, 1.56 for each ml/kg increase; 95% confidence interval, 1.12-2.23) was associated with development of postoperative respiratory failure. The interaction between larger VT and fluid administration was also statistically significant (odds ratio, 1.36; 95% confidence interval, 1.05-1.97).

Conclusion

Mechanical ventilation with large intraoperative VT is associated with increased risk of postpneumonectomy respiratory failure.