bluuebunny/crossref_metadata_2025 huggingface dataset:
A comparative study of imaginary time path integral based methods for quantum dynamics
Authors: Hone Tyler D. , Rossky Peter J. , Voth Gregory A.
Published: April 2006

The recently introduced approximate many-body quantum simulation method, ring polymer molecular dynamics (RPMD), is compared to the centroid molecular dynamics method (CMD). Comparisons of simulation results for liquid para-hydrogen at two state points and liquid ortho-deuterium at one state point are presented. The calculated quantum correlation functions for the two methods are shown to be in good agreement with one another for a large portion of the time spectrum. However, as the quantum mechanical nature of the system increases, RPMD is less accurate in predicting the kinetic energy of the system than is CMD. A simplified and highly efficient algorithm is proposed which largely corrects this deficiency.
A fragment energy assembler method for Hartree-Fock calculations of large molecules
Authors: Li Wei , Fang Tao , Li Shuhua
Published: April 2006

We present a fragment energy assembler approach for approximate Hartree-Fock (HF) calculations of macromolecules. In this method, a macromolecule is divided into small fragments with appropriate size, and then each fragment is capped by its neighboring fragments to form a subsystem. The total energy of the target system is evaluated as the sum of the fragment energies of all fragments, which are available from conventional HF calculations on all subsystems. By applying the method to a broad range of molecules, we demonstrate that the present approach could yield satisfactory HF energies for all studied systems.
A QUICKSTEP-based quantum mechanics/molecular mechanics approach for silica
Authors: Zipoli Federico , Laino Teodoro , Laio Alessandro , Bernasconi Marco , Parrinello Michele
Published: April 2006

Quantum mechanics/molecular mechanics (QM/MM) approaches are currently used to describe several properties of silica-based systems, which are local in nature and require a quantum description of only a small number of atoms around the site of interest, e.g., local chemical reactivity or spectroscopic properties of point defects. We present a QM/MM scheme for silica suitable to be implemented in the general QM/MM framework recently developed for large scale molecular dynamics simulations, within the QUICKSTEP approach to the description of the quantum region. Our scheme has been validated by computing the structural and dynamical properties of an oxygen vacancy in α-quartz, a prototypical defect in silica. We have found that good convergence in the Si–Si bond length and formation energy is achieved by using a quantum cluster of only eight atoms in size. We check the suitability of the method for molecular dynamics and evaluate the Si–Si bond frequency from the velocity-velocity correlation function.
Method to compensate for fluctuations in optical power delivered to a near-field scanning optical microscope
Authors: Schick I. C. , Yarbrough J. M. , Allen C. G. , Collins R. T.
Published: April 2006

Near-field scanning optical microscopy (NSOM) is a scanning probe technique that uses a tapered optical fiber to probe optical characteristics of a surface in registry with topography. Light can either be injected into the sample or collected from the sample via the subwavelength aperture formed at the tip of the probe. While operating in injection mode, variations in the optical power delivered to the probe, and consequently variations in the optical flux through the aperture, place limits on the imaging of spatial variations in optical properties. We present a novel method utilizing bend loss in an optical fiber to correct for variations in the optical flux of the aperture of a NSOM probe.
Three-dimensional endoscopic optical coherence tomography by use of a two-axis microelectromechanical scanning mirror
Authors: Jung Woonggyu , McCormick Daniel T. , Zhang Jun , Wang Lei , Tien Norman C. , Chen Zhongping
Published: April 2006

We present a three-dimensional (3D) endoscopic optical coherence tomography (OCT) system based on a dual-axis scanning microelectromechanical system (MEMS) mirror. The diameter of the MEMS mirror was 1.2mm and both axes were capable of scanning greater than 20° with linearity. The endoscopic MEMS probe was integrated with an OCT system and volume images were obtained at a rate of 3frames∕s by means of two-axis lateral scanning combined with an axial scan. In the initial investigations, 3D OCT images of healthy rabbit trachea as well as images of normal and cancerous regions of hamster cheek pouch tissue were obtained.
Fullerene nanowires on a vicinal gold surface
Authors: Néel N. , Kröger J. , Berndt R.
Published: April 2006

Long and narrow fullerene stripes have been fabricated on a vicinal gold surface by utilizing faceting of Au(433) substrates upon C60 adsorption and subsequent annealing. The observed step bunching is attributed to a lowering of the facet-free energy. This surface morphology is a promising template candidate for subsequent deposition of functional units.
High-power and high-efficiency midwave-infrared interband cascade lasers
Authors: Canedy C. L. , Bewley W. W. , Lindle J. R. , Kim C. S. , Kim M. , Vurgaftman I. , Meyer J. R.
Published: April 2006

A ten-stage interband cascade laser emitting at 3.3–3.6μm exhibits a voltage drop only 4% above the theoretical minimum, and operates to room temperature in pulsed mode. At 78K, a five-stage device mounted epitaxial-side-up with coated facets has a maximum cw wallplug efficiency of 21%, and a second device produces up to 1.1W of cw power.
Nanocrystalline Co-ferrite films with high perpendicular coercivity
Authors: Yin Jianhua , Ding Jun , Liu Binghai , Miao Xiangshui , Chen Jingsheng
Published: April 2006

Co-ferrite films were prepared using pulsed laser deposition at low substrate temperatures in this work. Magnetic properties of these films have been investigated in the function of substrate temperature and film thickness. A perpendicular coercivity as high as 12.5kOe has been achieved in the Co-ferrite film with a thickness of 33nm deposited at 550°C. The high coercivity mechanism is possibly associated with nanocrystalline structure, textured structure, and presence of relatively large residual strain.
Monolithically integrated optical modulator based on polycrystalline Ba0.7Sr0.3TiO3 thin films
Authors: Xu Zhimou , Suzuki Masato , Tanushi Yuichiro , Yokoyama Shin
Published: April 2006

Good-quality polycrystalline Ba0.7Sr0.3TiO3 (BST0.7) thin films were deposited on fused silica substrates and Si substrates having a thick amorphous SiO2 layer at a relatively low temperature of 550°C by spin-coating metal organic solutions. The thin films were highly transparent to light in the ultraviolet to near-infrared wavelength regions. The optical propagation loss for a 5-μm-wide and 300-nm-thick polycrystalline waveguide based on BST0.7 was about 17dB∕cm at a wavelength of 632.8nm. An electro-optic Mach-Zehnder interferometer modulator based on the polycrystalline BST0.7 thin film was monolithically integrated on a Si substrate with standard lithography and wet etching. Optical modulation was successfully demonstrated. The estimated electro-optic coefficient (6.7pm∕V) is the highest reported so far for this kind of film deposited on a fused silica substrate or a Si substrate with an amorphous SiO2 layer.
Element interactions limit soil carbon storage
Authors: van Groenigen Kees-Jan , Six Johan , Hungate Bruce A. , de Graaff Marie-Anne , van Breemen Nico , van Kessel Chris
Published: April 2006

Rising levels of atmospheric CO
2
are thought to increase C sinks in terrestrial ecosystems. The potential of these sinks to mitigate CO
2
emissions, however, may be constrained by nutrients. By using metaanalysis, we found that elevated CO
2
only causes accumulation of soil C when N is added at rates well above typical atmospheric N inputs. Similarly, elevated CO
2
only enhances N
2
fixation, the major natural process providing soil N input, when other nutrients (e.g., phosphorus, molybdenum, and potassium) are added. Hence, soil C sequestration under elevated CO
2
is constrained both directly by N availability and indirectly by nutrients needed to support N
2
fixation.
Vailulu’u Seamount, Samoa: Life and death on an active submarine volcano
Authors: Staudigel Hubert , Hart Stanley R. , Pile Adele , Bailey Bradley E. , Baker Edward T. , Brooke Sandra , Connelly Douglas P. , Haucke Lisa , German Christopher R. , Hudson Ian , Jones Daniel , Koppers Anthony A. P. , Konter Jasper , Lee Ray , Pietsch Theodore W. , Tebo Bradley M. , Templeton Alexis S. , Zierenberg Robert , Young Craig M.
Published: April 2006

Submersible exploration of the Samoan hotspot revealed a new, 300-m-tall, volcanic cone, named Nafanua, in the summit crater of Vailulu’u seamount. Nafanua grew from the 1,000-m-deep crater floor in <4 years and could reach the sea surface within decades. Vents fill Vailulu’u crater with a thick suspension of particulates and apparently toxic fluids that mix with seawater entering from the crater breaches. Low-temperature vents form Fe oxide chimneys in many locations and up to 1-m-thick layers of hydrothermal Fe floc on Nafanua. High-temperature (81°C) hydrothermal vents in the northern moat (945-m water depth) produce acidic fluids (pH 2.7) with rising droplets of (probably) liquid CO2. The Nafanua summit vent area is inhabited by a thriving population of eels (Dysommina rugosa) that feed on midwater shrimp probably concentrated by anticyclonic currents at the volcano summit and rim. The moat and crater floor around the new volcano are littered with dead metazoans that apparently died from exposure to hydrothermal emissions. Acid-tolerant polychaetes (Polynoidae) live in this environment, apparently feeding on bacteria from decaying fish carcasses. Vailulu’u is an unpredictable and very active underwater volcano presenting a potential long-term volcanic hazard. Although eels thrive in hydrothermal vents at the summit of Nafanua, venting elsewhere in the crater causes mass mortality. Paradoxically, the same anticyclonic currents that deliver food to the eels may also concentrate a wide variety of nektonic animals in a death trap of toxic hydrothermal fluids.
A collagenous protective coat enables
Metarhizium anisopliae
to evade insect immune responses
Authors: Wang Chengshu , St. Leger Raymond J.
Published: April 2006

The ubiquitous fungal pathogen
Metarhizium anisopliae
kills a wide range of insects. Host hemocytes can recognize and ingest its conidia, but this capacity is lost on production of hyphal bodies. We show that the unusual ability of hyphal bodies to avoid detection depends on a gene (
Mcl1
) that is expressed within 20 min of the pathogen contacting hemolymph. A mutant disrupted in
Mcl1
is rapidly attacked by hemocytes and shows a corresponding reduction of virulence to
Manduca sexta
.
Mcl1
encodes a three domain protein comprising a hydrophilic, negatively charged N-terminal region with 14 cysteine residues, a central region comprising tandem repeats (GXY) characteristic of collagenous domains, and a C-terminal region that includes a glycosylphosphatidylinositol-dependent cell wall attachment site. Immunofluorescence assay showed that hyphal bodies are covered by the N-terminal domains of MCL1. The collagen domain became antibody accessible after treatment with DTT, suggesting that the N termini are linked by interchain disulfide bonds and are presented on the cell surface by extended collagenous fibers. Studies with staining reagents and hemocyte monolayers showed that MCL1 functions as an antiadhesive protective coat because it masks antigenic structural components of the cell wall such as β-glucans, and because its hydrophilic negatively charged nature makes it unattractive to hemocytes. A survey of 54 fungal genomes revealed that seven other species have proteins with collagenous domains suggesting that MCL1 is a member of a patchily distributed gene family.
Endemic Multidrug-Resistant Pseudomonas aeruginosa in Critically Ill Patients
Authors: Ortega Bryan , Groeneveld A. B. Johan , Schultsz Constance
Published: April 2006

Objective:

To describe the epidemiology of endemic multidrug-resistant Pseudomonas aeruginosa colonizations and infections in critically ill patients.

Design:

Prospective study on bacterial strain typing and retrospective cohort study of charts of patients in the intensive care unit (ICU).

Patients:

Fifty-three patients with P. aeruginosa isolated from clinical cultures in 2001 were selected, divided into those with P. aeruginosa in vitro resistant to at least two classes of antibiotics (multidrug-resistant, n = 18) and those susceptible to all or resistant to only one antibiotic (susceptible, n = 35).

Results:

Risk factors for multidrug-resistant P. aeruginosa included maxillary sinusitis, long-dwelling central venous catheters, prolonged use of certain antibiotics, a high lung injury score, and prolonged mechanical ventilation and duration of stay. The frequency of colonization (approximately 50%) versus infection (ie, ventilator-associated pneumonia) did not differ between the groups. On amplified fragment-length polymorphism analysis, 64% of the multidrug-resistant strains had been potentially transmitted via cross-colonization and 36% had probably originated endogenously. ICU mortality was 22% in the multidrug-resistant group and 23% in the susceptible group, although the duration of mechanical ventilation was longer in the former.

Conclusions:

Patients with sinusitis who stayed in the ICU longer, were ventilated longer because of acute lung injury, received antibiotics for longer durations, and had long-dwelling central venous catheters ran an elevated risk of acquiring multidrug-resistant P. aeruginosa. These patients did not have a higher mortality than patients with susceptible P. aeruginosa. Prevention of the emergence of multidrug-resistant strains requires changes in infection control measures and antibiotic policies in our ICU.
Evaluation of Three Molecular Typing Techniques for Nonfermentative Gram-Negative Bacilli
Authors: Silbert Suzane , Pfaller Michael A. , Hollis Richard J. , Barth Afonso L. , Sader Hélio S.
Published: April 2006

Objective:

To evaluate three different DNA techniques for typing nonfermentative gram-negative bacilli isolated from Latin American hospitals.

Design:

One hundred twenty-six nonfermentative gram-negative bacilli were typed.

Participants:

Pseudomonas aeruginosa (n = 64) and Acinetobacter baumannii (n = 42) samples were obtained from blood cultures of patients admitted to 10 medical centers in Latin America during 1998 and Stenotrophomonas maltophilia (n = 20) samples were obtained from patients admitted to the Hospital São Paulo between 1999 and 2001.

Methods:

All samples were typed using automated ribotyping, PFGE, and ERIC-PCR. The discriminatory power for each technique was calculated using Hunter's generalized formula.

Results:

All strains could be typed by automated ribotyping and ERIC-PCR, but two strains (1.6%) were not typeable by PFGE. All three techniques showed 100% reproducibility. The time to obtain the results was shorter for automated ribotyping and ERIC-PCR compared with PFGE. Likewise, the costs for ERIC-PCR and PFGE were lower than those for automated ribotyping. The interpretation of results was more complicated and more difficult with ERIC-PCR than with both PFGE and automated ribotyping. All techniques presented excellent discriminatory power for P. aeruginosa (0.98). PFGE presented the highest discriminatory power (0.94) for A. baumannii, and both PFGE and ERIC-PCR showed higher discriminatory power (0.90 for both) than automated ribotyping (0.82) for S. maltophilia.

Conclusions:

PFGE showed the highest discriminatory power for typing these nonfermentative gram-negative bacilli. However, automated ribotyping and ERIC-PCR can provide results in a shorter time period with similar discriminatory power.
Molecular Epidemiology of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae Isolated From Environmental and Clinical Specimens in a Cardiac Surgery Intensive Care Unit
Authors: Kac Guillaume , Podglajen Isabelle , Vaupré Sabine , Colardelle Nathalie , Buu-Hoï Annie , Gutmann Laurent
Published: April 2006

Objectives:

To investigate environmental contamination by extended-spectrum beta-lactamase-producing Enterobacteriaceae and to perform a comparative molecular analysis of clinical and environmental strains.

Setting:

A 17-bed cardiac surgery intensive care unit of a 480-bed university teaching hospital.

Methods:

Following an outbreak of extended-spectrum beta-lactamase-producing Enterobacteriaceae, an environmental survey revealed extensive contamination of the environment (particularly faucets, sink drains, and the joints of the countertops) by extended-spectrum beta-lactamase-producing Enterobacteriaceae. Environmental strains were compared with clinical strains by pulsed-field gel electrophoresis and randomly amplified polymorphic DNA.

Results:

A total of 62 environmental strains belonging to 4 species of extended-spectrum beta-lactamase-producing Enterobacteriaceae were analyzed and compared with 43 clinical strains obtained from 34 patients. Comparative molecular analysis revealed 4 identical or closely related patterns (3 from Klebsiella oxytoca and 1 from Enterobacter cloacae) between environmental and clinical strains.

Conclusions:

Moist surfaces may serve as sources of multiply resistant Enterobacteriaceae in the intensive care unit. Identification and disinfection of such sources may therefore be helpful in prevention and control of outbreaks.
Emergence of Resistance in Pseudomonas aeruginosa and Acinetobacter Species After the Use of Antimicrobials for Burned Patients
Authors: Ferreira Andrea C. B. , Gobara Satiko , Costa Silvia F. , Sauaia Nairn , Mamizuka Elsa M. , Van der Heijden Inneke M. , Soares Robson E. , Almeida Gisele D. , Fontana Carlos , Levin Anna S.
Published: April 2006

Objectives:

To evaluate the emergence of resistance of Pseudomonas aeruginosa and Acinetobacter species to imipenem, ciprofloxacin, or both after the use of these drugs and to compare resistant with susceptible isolates by molecular typing.

Design:

Cohort study.

Setting:

Burn intensive care unit (ICU) with 4 beds in a tertiary-care university hospital.

Methods:

During 16 months, surveillance cultures were performed for all patients admitted to the ICU. Demographic information was obtained for each patient. Molecular typing was done by pulsed-field gel electrophoresis using restriction enzymes for 71 isolates of P. aeruginosa and Acinetobacter species.

Results:

Thirty-four patients were admitted and 22 were colonized by susceptible P. aeruginosa or Acinetobacter species before they used the antimicrobials. Nine (41%) of these patients had a resistant isolate after antimicrobial use: 5 had used imipenem alone, 1 had used ciprofloxacin, and 3 had used both drugs. The interval between isolation of the susceptible and resistant isolates ranged from 4 to 25 days, but was 10 or more days for 6 patients. Molecular typing revealed that susceptible and resistant isolates from each patient were different and that although there were no predominant clones among susceptible isolates, there was a predominant clone among resistant isolates of P. aeruginosa and of Acinetobacter.

Conclusions:

Resistance was not due to the acquisition of resistance mechanisms by a previously susceptible strain, but rather to cross-transmission. Although various measures involving antimicrobial use have received great attention, it would seem that practices to prevent cross-transmission are more important in controlling resistance.
Improving Influenza Immunization Rates Among Healthcare Workers Caring for High-Risk Pediatric Patients
Authors: Bryant Kristina A. , Stover Beth , Cain Linda , Levine Gail L. , Siegel Jane , Jarvis William R.
Published: April 2006

Objective:

To assess influenza vaccination rates of healthcare workers (HCWs) in neonatal intensive care units (NICUs), pediatric intensive care units (PICUs), and oncology units in Pediatric Prevention Network (PPN) hospitals.

Participants:

Infection control practitioners and HCWs in NICUs, PICUs, and oncology units.

Methods:

In November 2000, posters, electronic copies of a slide presentation, and an influenza fact sheet were distributed to 32 of 76 PPN hospitals. In January 2001, a survey was distributed to PPN hospital participants to obtain information about the immunization campaigns. On February 7, 2001, a survey of influenza immunization was conducted among HCWs in NICU, PICU, and oncology units at participating hospitals.

Results:

Infection control practitioners from 19 (25%) of the 76 PPN hospitals completed the surveys. The median influenza immunization rate was 43% (range, 12% to 63%), with 7 hospitals exceeding 50%. HCWs (n = 1,123) at 15 PPN hospitals completed a survey; 53% of HCWs reported receiving influenza immunization. Immunization rates varied by work site: 52% in NICUs and PICUs compared with 60% in oncology units. Mobile carts and PPN educational fact cards were associated with higher rates among these subpopulations (P < .001) (361 [63%] of 575 vs 236 [44%] of 541 for mobile carts; 378 [60%] of 633 vs 219 [45%] of 483 for fact cards).

Conclusion:

Despite delayed distribution of influenza vaccine during the 2000–2001 season, immunization rates at 7 hospitals and among HCWs in high-risk units exceeded the National Association of Children's Hospitals and Related Institutions goal of 50%.
Work-Site-Based Influenza Vaccination in Healthcare and Non-Healthcare Settings
Authors: D'Heilly Sarah J. , Nichol Kristin L.
Published: April 2006

Objective:

To better understand work-site–based programs for influenza vaccination.

Design:

Self-administered, mailed questionnaire.

Setting:

Healthcare and non-healthcare companies.

Participants:

Random sample of 2,000 members of the American Association of Occupational Health Nurses.

Results:

The response rate was 55%, and 88% of the respondents were employed by companies sponsoring work-site influenza vaccination. Thirty-two percent of respondents worked for healthcare and healthcare-related services companies. Healthcare companies were more likely to sponsor worksite-based vaccination (94% vs 85%; P < .0001) compared with non-healthcare companies. Healthcare companies were also more likely to encourage vaccination of high-risk employees (70% vs 55%; P < .0001) and cover its cost (86% vs 61%; P < .0001). Multivariate logistic regression was used to determine factors associated with highly successful vaccination. Being a healthcare-related company (OR, 2.1; CI95 1.4–3.2; P < .0001), employers covering the vaccination cost (OR, 3.1; CI95, 1.4–6.6; P = .004), having more experience with work-site vaccination (OR, 1.6; CI95, 1.0–2.4; P = .036), and management encouraging vaccination (OR, 2.6; CI95, 1.4–4.9; P = .002) were associated with highly successful programs.

Conclusions:

Most of the occupational health nurses surveyed work for employers sponsoring work-site vaccination, and 32% were employed by healthcare and related services companies. Healthcare companies were more likely to sponsor worksite–based vaccination and to vaccinate most of their employees; however, only 18% had vaccination rates higher than 50%. Strategies need to be developed to increase vaccination rates so that benefits of vaccination can be realized by employers and employees.
Cockroaches as Potential Vectors of Nosocomial Infections
Authors: Pai Hsiu-Hua , Chen Wei-Chen , Peng Chien-Fang
Published: April 2006

Objective:

To determine the possible role of cockroaches in the epidemiology of nosocomial infections.

Design:

Epidemiologic investigation of bacteria and fungi in cockroaches and evaluation of the antibiotic resistance of the bacteria isolated from the insects.

Setting:

Ninety hospitals in Kaohsiung City and Kaohsiung County in Taiwan.

Methods:

Cockroaches were collected in clinical and nonclinical areas and microorganisms were isolated from their external surface and alimentary tract. The susceptibilities of Staphylococcus aureus, Enterococcus species, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Serratia marcescens, and Proteus species to 17 antibiotics were tested.

Results:

Cockroach infestation was found in 46.7% of the hospitals studied. Two hundred three cockroaches were collected (139 Periplaneta americana and 64 Blattella germanica). Periplaneta americana was found more often in nonclinical areas (64.5%) and B. germanica in clinical areas (78.1%). There was no statistically significant difference between Periplaneta americana (98.6%) and B. germanica (96.9%) regarding overall isolation rate (P > .05). However, 33 species of bacteria and 16 species of fungi were isolated from Periplaneta americana and only 23 and 12, respectively, from B. germanica. Resistance to ampicillin (13.7% to 100%), chloramphenicol (14.3% to 71.4%), tetracycline (14.3% to 73.3%), and trimethoprim-sulfamethoxazole (14.3% to 57.1%) was found in two gram-positive and five gram-negative bacteria.

Conclusion:

Because cockroach infestation occurred in more than 40% of the hospitals and nearly all of the cockroaches harbored bacteria with multidrug resistance and fungi, cockroaches may play a potential role in the epidemiology of nosocomial infections in those hospitals.
Pneumococcal Immunization in Older Adults: Implications for the Long-Term–Care Setting
Authors: Loeb Mark , Stevenson Kurt B. ,   SHEA Long-Term-Care Committee
Published: April 2006

Objectives:

To compare the efficacy of the polysaccharide pneumococcal vaccine in older adults between clinical trial and observational studies and to discuss the implications for long-term–care facilities (LTCFs).

Data Source:

A Medline search (to April 2003).

Study Selection:

All meta-analyses of randomized and quasi-randomized trials of pneumococcal vaccines with placebo or no treatment were sought. All cohort or case–control studies were sought.

Data Synthesis:

Of the 16 individual randomized clinical trials included in the reviews, 8 compared pneumococcal vaccine in individuals 55 years and older individuals. Only one study specifically addressed LTCF residents. Although no significant protective effect of the vaccine in elderly subpopulations was found, on the basis of wide confidence intervals and small subpopulation sample sizes, beneficial effects, particularly for pneumococcal bacteremia, could not be ruled out. Of the individual observational studies, 11 specifically evaluated vaccine efficacy in older adults. Vaccine efficacy was demonstrated in 9 of the 11 studies with no protective effect was shown in 2 studies.

Conclusion:

Although the pooling of clinical trial data does not demonstrate significant efficacy of the pneumococcal polysaccharide vaccine in subgroups of older adults, these subgroup studies lacked power to show significant differences. Observational studies repeatedly demonstrate efficacy in older adults, and the vaccine has been demonstrated to be cost-effective and safe. It is strongly promoted by U.S. and Canadian advisory committees. On the basis of this available evidence, the pneumococcal polysaccharide vaccine should currently be recommended for older adults, especially those who are residents of LTCFs.
Foundations of the Severe Acute Respiratory Syndrome Preparedness and Response Plan for Healthcare Facilities
Authors: Srinivasan Arjun , McDonald Lawrence C. , Jernigan Daniel , Helfand Rita , Ginsheimer Kathleen , Jernigan John , Chiarello Linda , Chinn Raymond , Parashar Umesh , Anderson Larry , Cardo Denise ,   SARS Healthcare Preparedness and Response Plan Team
Published: April 2006

Objective:

To help facilities prepare for potential future cases of severe acute respiratory syndrome (SARS).

Design and Participants:

The Centers for Disease Control and Prevention (CDC), assisted by members of professional societies representing public health, healthcare workers, and healthcare administrators, developed guidance to help facilities both prepare for and respond to cases of SARS.

Interventions:

The recommendations in the CDC document were based on some of the important lessons learned in healthcare settings around the world during the SARS outbreak of 2003, including that (1) a SARS outbreak requires a coordinated and dynamic response by multiple groups; (2) unrecognized cases of SARS-associated coronavirus are a significant source of transmission; (3) restricting access to the healthcare facility can minimize transmission; (4) airborne infection isolation is recommended, but facilities and equipment may not be available; and (5) staffing needs and support will pose a significant challenge.

Conclusions:

Healthcare facilities were at the center of the SARS outbreak of 2003 and played a key role in controlling the epidemic. Recommendations in the CDC's SARS preparedness and response guidance for healthcare facilities will help facilities prepare for possible future outbreaks of SARS.
An Outbreak of Bacteremias Associated With Mycobacterium mucogenicum in a Hospital Water Supply
Authors: Kline Susan , Cameron Sarah , Streifel Andrew , Yakrus Mitchell A. , Kairis Frank , Peacock Keith , Besser John , Cooksey Robert C.
Published: April 2006

Objective:

To investigate and determine the cause of an outbreak of Mycobacterium mucogenicum bacteremias in bone marrow transplant (BMT) and oncology patients.

Design:

Case–control study and culturing of hospital water sources. Isolates were typed using molecular methods.

Setting:

University-affiliated, tertiary-care medical center.

Patients:

Case-patients were adult and pediatric BMT patients or hematopoietic stem cell transplant (BMT) (n = 5) and oncology (n = 1) patients who were diagnosed as having M. mucogenicum bacteremia during the study period of August through November 1998. Two control-patients were selected for each case-patient matched by age, time of hospitalization, inpatient unit, and type of patient (BMT or oncology).

Results:

There were no significant differences between case-patients and control-patients regarding intravenous products received or procedures performed, frequency of bathing, neutropenia, or steroid use. Nontuberculous mycobacteria were isolated from several water sources at the medical center including tap water from sinks and showerheads, the hospital hot water source, and the city water supply to the hospital. Analysis by multilocus enzyme electrophoresis and randomly amplified polymorphic DNA showed a match between one patient's blood isolate and an isolate from shower water from that patient's prior hospital room.

Conclusions:

The cause of the outbreak seemed to be water contamination of central venous catheters (CVCs) during bathing. A recommendation in early 2001 that CVCs be protected from water during bathing was followed by no M. mucogenicum bacteremias during the second half of 2001, only one in 2002, and none at all during 2003.
Screening and Treatment of Latent Tuberculosis Among Healthcare Workers at Low, Moderate, and High Risk for Tuberculosis Exposure: A Cost-Effectiveness Analysis
Authors: Salpeter Shelley R. , Salpeter Edwin E.
Published: April 2006

Objective:

To evaluate cost-effective screening and treatment strategies for healthcare workers (HCWs) at risk for tuberculosis exposure.

Design:

A Markov model was developed to track three hypothetical cohorts of HCWs at low, moderate, and high risk for tuberculosis exposure. For those found to be tuberculin reactors at entry, the choice was for isoniazid treatment or no treatment. For those without tuberculin reactivity, the choice of screening intervals was 6 months, 1 year, 2 years, or 5 years. Outcomes measured were tuberculosis cases, death, life expectancy, and cost. Assumptions were derived from published data and analyses.

Results:

Treatment of initial reactors with isoniazid in all three risk groups was associated with a net savings of $14,800 to $15,700 for each tuberculosis case prevented. For those without evidence of infection at entry, the most cost-effective screening interval was 1 year for high-risk groups, 2 years for moderate-risk groups, and 5 years for low-risk groups, with a net savings $0.20 to $26 per HCW per year. Screening at a more frequent interval was still cost-effective.

Conclusions:

For HCWs found to be tuberculin reactors, treatment of their latent infection is to their benefit and is associated with a net cost-savings. Regular tuberculin screening of HCWs can be cost-effective or result in a net cost-savings. Each institution could use its own skin test surveillance data to create an optimum screening program for its employees. However, for most HCWs, a 1-year screening interval would be a cost-effective and safe choice.
Tuberculosis in Healthcare Workers Caring for a Congenitally Infected Infant
Authors: Mouchet Françoise , Hansen Valérie , Van Herreweghe Inge , Vandenberg Olivier , Van Hesse Régine , Gérard Michèle , Toppet Michèle , Wanlin Maryse , Toppet Véronique , Casimir Georges , Haumont Dominique , Levy Jack
Published: April 2006

Objective:

To assess the extent of nosocomial transmission of tuberculosis among infants, family members, and healthcare workers (HCWs) who were exposed to a 29-week-old premature infant with congenital tuberculosis, diagnosed at 102 days of age.

Design:

A prospective exposure investigation using tuberculin skin test (TST) conversion was conducted. Contacts underwent two skin tests 10 to 12 weeks apart. Clinical examination and chest radiographs were performed to rule out disease. Isoniazid prophylaxis was administered to exposed infants at higher risk.

Setting:

A neonatal intensive care unit in an urban hospital in Brussels, Belgium.

Participants:

Ninety-seven infants, 139 HCWs, and 180 visitors.

Results:

Newly positive TST results occurred in HCWs who had been in close contact with the infant. Six (19%) of 32 primary care nurses and physicians had TST conversions and received treatment. Among the 97 exposed infants, 85 were screened and 34 were identified as at higher risk of infection. Of these, 27 received preventive isoniazid. None of the infants and none of the 93 other infants' family members evaluated were infected.

Conclusions:

Congenital tuberculosis in an infant poses a risk for nosocomial transmission to HCWs. Delayed diagnosis of this rare disease and close proximity are the most important factors related to transmission.
Risk of Tuberculous Infection Among Healthcare Workers in a Tertiary-Care Hospital in Ankara, Turkey
Authors: Keskiner Ramazan , Ergönül Önder , Demiroglu Ziya , Eren Sebnem , Baykam Nurcan , Dokuzoguz Basak
Published: April 2006

Objective:

To determine risk factors for tuberculin skin test (TST) positivity among healthcare workers (HCWs).

Design:

Two-step TST was performed in 2002.

Setting:

Tertiary-care hospital in Ankara, Turkey.

Participants:

A sample of 491 hospital HCWs were included. Information related to demographics, profession, work duration, department, and individual and family history of tuberculosis (TB) was obtained by a structured questionnaire.

Results:

Four hundred eight (83%) had two-step TST positivity. On multivariate analysis, male physicians (relative risk [RR], 1.5; 95% confidence interval [CI95], 1.23–1.69; P = .001), nurses (RR, 1.5; CI95, 1.29–1.66; P = .005), radiology technicians (RR, 1.7; CI95, 1.35–1.73; P = .002), laboratory technicians (RR, 1.6; CI95, 1.3–1.74; P = .007), and male housekeepers (RR, 1.6; CI95, 1.38–1.7; P < .001) had a higher risk than did female physicians. Among laboratory technicians, radiology technicians had the highest TST positivity (85%). HCWs working for less than 1 year (RR, 0.8; CI95, 0.72–0.98; P = .027) had a lower risk of infection. The HCWs having bacille Calmette–Guérin vaccination (RR, 1.12; CI95, 1.08–1.45) had higher TST positivity.

Conclusion:

Male physicians, nurses, and laboratory technicians had increased risk of Mycobacterium tuberculosis infection in this setting, but community exposure likely accounted for most infections.
Periodically Changing Ventilator Circuits Is Not Necessary to Prevent Ventilator-Associated Pneumonia When a Heat and Moisture Exchanger Is Used
Authors: Lorente Leonardo , Lecuona María , Galván Ramón , Ramos María J. , Mora María L. , Sierra Antonio
Published: April 2006

Objective:

To analyze the efficacy of periodically changing ventilator circuits for decreasing the rate of ventilator-associated pneumonia when a heat and moisture exchanger (HME) is used for humidification. The Centers for Disease Control and Prevention recommended not changing the circuits periodically.

Design:

Randomized, controlled trial conducted between April 2001 and August 2002.

Setting:

A 24-bed, medical–surgical intensive care unit in a 650-bed, tertiary-care hospital.

Patients:

All patients requiring mechanical ventilation during more than 72 hours from April 2001 to August 2002.

Interventions:

Patients were randomized into two groups: (1) ventilation with change of ventilator circuits every 48 hours and (2) ventilation with no change of circuits. Throat swabs were taken on admission and twice weekly until discharge to classify pneumonia as endogenous or exogenous.

Results:

Three hundred four patients (143 from group 1 and 161 from group 2) with similar characteristics (age, gender, Acute Physiology and Chronic Health Evaluation II score, diagnostic group, and mortality) were analyzed. There was no significant difference in the rate of pneumonia between the groups (23.1% vs 23.0% and 15.5 vs 14.8 per 1,000 ventilator-days). There was no significant difference in the incidence of exogenous pneumonia per 1,000 days of mechanical ventilation (1.71 vs 1.25). There was no difference in the distribution of microorganisms causing pneumonia.

Conclusions:

Circuit change using an HME for humidification does not decrease pneumonia and represents an unnecessary cost.
An Outbreak of Pseudomonas aeruginosa Pneumonia and Bloodstream Infection Associated With Intermittent Otitis Externa in a Healthcare Worker
Authors: Zawacki Anne , O'Rourke Edward , Potter-Bynoe Gail , Macone Ann , Harbarth Stephan , Goldmann Donald
Published: April 2006

Arstract

Objectives:

To investigate an outbreak of Pseudomonas aeruginosa pneumonia and bloodstream infection among four neonates, determine risk factors for infection, and implement preventive strategies.

Design:

Retrospective case finding; prospective surveillance cultures of patients, personnel, and environmental sites; molecular typing by pulsed-field gel electrophoresis; and a matched case-control study.

Patients and Setting:

Neonates in the level-III neonatal intensive care unit of a tertiary-care pediatric institution.

Interventions:

Cohorting of patients with positive results for P. aeruginosa, work restrictions for staff with positive results, implementation of an alcohol-based hand product, review of infection control policies and procedures, and closure of the unit until completion of the investigation.

Results:

Seven (4%) of 190 environmental cultures and 5 (3%) of 178 cultures of individual healthcare workers' hands grew P. aeruginosa. All four outbreak isolates and one previous bloodstream isolate were genotypically identical, as were the P. aeruginosa isolates from the hands and external auditory canal of a healthcare worker with intermittent otitis externa. Four of 5 case-patients versus 5 of 15 matched control-patients had been cared for by this healthcare worker (P = .05). The healthcare worker was treated and no further cases occurred.

Conclusions:

These findings suggest that a healthcare worker with intermittent otitis externa may have caused this cluster of fatal P. aeruginosa infections, adding the external ear to the list of colonized body sites that may serve as a source of potentially pathogenic organisms.
Booster Effect of Two-Step Tuberculin Skin Testing Among Hospital Employees From Areas With a High Prevalence of Tuberculosis
Authors: Al Mazrou Abdulrahman M.
Published: April 2006

During a baseline survey of TST, 236 nurses underwent a two-step TST. Overall, 29 (12%) showed boosting. All age groups showed boosting; the rate was 9.7% in those younger than 35 years. Subjects older than 45 years were more likely to have a booster effect than younger individuals (29% vs 10.1%).
Patterns of Handwashing Behavior and Visits to Patients on a General Medical Ward of Healthcare Workers
Authors: Raboud Janet , Saskin Refik , Wong Kurt , Moore Christine , Parucha Grace , Bennett Jocelyn , Green Karen , Low Don , Loeb Mark , Simor Andy , McGeer Allison
Published: April 2006

Objective:

To obtain accurate data regarding the handwashing behavior and patterns of visits to patients by healthcare workers (HCWs).

Methods:

All visits by HCWs to selected patient rooms were recorded for 3 days and 2 nights. Additionally, 5 nurses were observed for 1 day each and 2 nurses were observed for 1 night each. Nurses were observed for their entire shifts and all of their activities were recorded.

Setting:

A general medical ward in a tertiary-care hospital.

Participants:

Convenience samples of HCWs and patients.

Results:

Patients were visited every 25 minutes on average. Monitoring rooms and observing nurses resulted in similar rates of patient visits. The highest level of risk was contact with body fluids in 11% of visits and skin in 40% of visits. The overall rate of handwashing was 46%; however, the rate was higher for visits involving contact with body fluids (81%) and skin (61%). Nurses returned immediately to the same patient 45% of the time. The rate of handwashing was higher for the last of a series of visits to a patient's room (53% vs 30%, P < .0001).

Conclusions:

Nurses adjusted their handwashing rates in accordance with the risk level of each visit. Monitoring patient rooms and observing nurses yielded similar estimates of patient visits and proportions of visits involving contact with skin or body fluids. Education programs about hand hygiene may be more effective if patterns of care and levels of risk are incorporated into recommendations.
Alcohol-Based Handrub: Evaluation of Technique and Microbiological Efficacy with International Infection Control Professionals
Authors: Widmer Andreas F. , Dangel Marc
Published: April 2006

Background And Objective:

The Centers for Disease Control and Prevention has published a new guideline on hand hygiene promoting the use of the alcohol-based handrub, but the technique was not addressed. The goal of this study was to evaluate the influence of technique on the efficacy of the alcohol-based handrub.

Participants:

Healthcare workers (HCWs) attending a course in hospital epidemiology.

Methods:

A fluorescent dye was added to a hand antiseptic, and hands were checked under ultraviolet light after antiseptic cleansing. Data regarding the numbers of predefined fluorescent areas on the skin were collected in addition to demographic data such as age, gender, job description, and job experience. Results of the visualization test were compared with the data from microbiological samples before and after the procedure by the hand plate technique.

Results:

Sixty HCWs were tested, 63% of whom had worked in infection control for more than 10 years. Sixty-six percent of all participants still had detectable bacteria after antisepsis. The mean log10 CFU reduction was 2.0 (range, 0–3.85). Twenty-five percent of all HCWs achieved less than 1.1 log10 CFU. Staphylococcus aureus was isolated from 13% (one of them being methicillin resistant) and gram-negative bacilli from 6.7%. After using the alcohol handrub, one subject still remained positive for S. aureus. Years of experience was the single most important factor predicting antimicrobial efficacy.

Conclusions:

Technique is of crucial importance in hand antisepsis. Major deficiencies were detected among even highly trained HCWs. Training should be provided before switching from handwashing to the alcohol handrub.
Ineffectiveness of Handwashing With Lotion Soap to Remove Nosocomial Bacterial Pathogens Persisting on Fingertips: A Major Link in Their Intrahospital Spread
Authors: Bottone Edward J. , Cheng Mark , Hymes Saul
Published: April 2006

The effectiveness of five 30-second handwashes with a non-antiseptic lotion soap to remove nosocomial pathogens (108CFU) applied to fingertips was studied. CFU for all species dropped rapidly after the first handwash; persistence (10 to 15 CFU) was maintained thereafter. Wiping hands with an antiseptic (70% isopropyl or 10% povidone-iodine) sponge removed persisters.
Assessment of a Novel Approach to Evaluate the Outcome of Endoscope Reprocessing
Authors: Sciortino C. V. , Xia Eric L. , Mozee Alberta
Published: April 2006

Objective:

To investigate and evaluate the use of a portable luminometer system for detecting contamination following the reprocessing and high-level disinfection of flexible endoscopes.

Design:

Random sampling of endoscopes spaced at 1- to 2-week intervals following normal use in patients.

Methods:

Portable luminometer system testing of 31 endoscopes undergoing reprocessing, 63 stored endoscopes, and 15 reprocessed endoscopes that underwent in-depth microbiological analysis. For testing with the portable luminometer system, samples were collected by swabbing a 100-cm2 shank surface area and the internal tip end orifice. Standardization of portable luminometer system results was performed in vitro by comparison of serial dilutions of known quantities of microorganisms and blood, tested before and after sterilization by autoclave. Microbiological analysis included Gram stain, culture for aerobic bacteria, and gene probes for Mycobacterium tuberculosis, herpes simplex viruses 1 and 2, and Cytomegalovirus. Trichrome and calcofluor white stains were used to detect parasites and fungi. Legionella was detected by stain with fluorescent-labeled monoclonal antibody.

Setting:

The gastroendoscopy unit of a Veterans Affairs hospital.

Results:

The portable luminometer system was capable of detecting microbial and cellular contamination of flexible endoscopes following high-level disinfection and reprocessing. The sensitivity of the assay was sufficient for detecting low-level contamination.

Conclusions:

The system provided a rapid microbiological outcome monitor for the cleaning and disinfection process. The system was easy to use and relatively accurate.
Burkholderia cepacia Infections Associated With Intrinsically Contaminated Ultrasound Gel: The Role of Microbial Degradation of Parabens
Authors: Hutchinson Jim , Runge Wendy , Mulvey Mike , Norris Gail , Yetman Marion , Valkova Nelly , Villemur Richard , Lepine Francois
Published: April 2006

Objective:

To describe an outbreak of serious nosocomial Burkholderia cepacia infections occurring after transrectal prostate biopsy associated with ultrasound gel intrinsically contaminated with paraben-degrading microorganisms.

Methods:

A retrospective chart review prompted by a blood culture isolate of B, cepacia. Identification of microorganisms in ultrasound gel in two Canadian centers and characterization by pulsed-field gel electrophoresis and assays for paraben degradation.

Setting:

Two Canadian university-affiliated, tertiary-care centers in Newfoundland and Alberta.

Results:

Six serious B. cepacia infections were identified at the two centers. Isolates of B. cepacia recovered from the blood of patients from both centers and the ultrasound gel used during the procedures were identical, confirming intrinsic contamination. Strains of Enterobacter cloacae isolated from ultrasound gel at the two centers were also identical. The ability to degrade parabens was proven for both B. cepacia and E. cloacae strains recovered from the ultrasound gel.

Conclusions:

Ultrasound gel is a potential source of infection. Contamination occurs at the time of manufacture, with organisms that degrade parabens, which are commonly used as stabilizing agents. There are far-reaching implications for the infection control community.