bluuebunny/crossref_metadata_2025 huggingface dataset:
Pseudo-Outbreak of Multidrug-ResistantMycobacterium tuberculosisAssociated With Presumed Laboratory Processing Contamination
Authors: Bearman Gonzalo , Vaamonde Carlos , Larone Davise , Drusin Lewis , Zuccotti Gianna
Published: February 2006

An investigation prompted by six positive cultures for multidrug-resistantMycobacterium tuberculosisduring a 7-week period found that an unusual resistance pattern, temporal proximity of laboratory processing, and identical DNA fingerprints supported the theory of cross-contamination. Laboratory processing procedures included specimen batching and multi-use vials of buffer solution. Processing procedures were changed and no additional cases of suspected cross-contamination have been observed. '(Infect Control Hosp Epidemiol 2002;23:622).
Isoniazid-Resistant Cavitary Tuberculosis in a Physician Following Isoniazid Prophylaxis
Authors: Karchmer Tobi B. , Phipps John D. , Giannetta Eve T. , Farr Barry M.
Published: February 2006

Single-drug prophylaxis is recommended after tuberculin skin test conversion, but not when there is active disease on chest radiograph because resistance develops frequently. Isoniazid-resistant tuberculosis developed in a physician receiving prophylaxis despite “faint left upper lobe soft tissue density” on chest radiograph. Ignoring active disease on chest x-ray renders this strategy counterproductive and cost ineffective. '(Infect Control Hosp Epidemiol 2002;23:622-625).
Factors Influencing Decisions Regarding Influenza Vaccination and Treatment: A Survey of Healthcare Workers
Authors: Steiner MaryAnn , Vermeulen Lee C. , Mullahy John , Hayney Mary S.
Published: February 2006

Surveys conducted in our healthcare facility evaluated factors associated with acceptance of influenza vaccination and opinions regarding influenza prevention and treatment and willingness to pay. Avoiding lost work and low risk were primary reasons for vaccine recipients and non-recipients, respectively. One-third of vaccine recipients would refuse vaccination if asked to pay at least $10.
Nosocomial Influenza at a Canadian Pediatric Hospital From 1995 to 1999: Opportunities for Prevention
Authors: Slinger Robert , Dennis Peggy
Published: February 2006

Nineteen cases of nosocomial influenza occurred at a pediatric hospital during a 5-year period. Only one of the nine children with chronic health conditions had been immunized. Length of stay was prolonged for seven children, with three intensive care unit admissions. We have now implemented strategies to decrease nosocomial influenza infection. (Infect Control Hosp Epidemiol 2002;23:627-629).
The Role ofClostridium difficileand Viruses as Causes of Nosocomial Diarrhea in Children
Authors: Langley Joanne M. , LeBlanc John C. , Hanakowski Martha , Goloubeva Olga
Published: February 2006

Objective:

We report surveillance of nosocomial diarrhea in children at our institution during the past decade and note different epidemiology of diarrhea due to viruses andClostridium difficile.

Design:

A prospective cohort study.

Setting:

A university-affiliated pediatric hospital with 180 beds serving an urban area and providing referral care for the Maritime Provinces of Canada.

Participants:

Children younger than 18 years.

Methods:

Surveillance was conducted from 1991 to 1999 using personal contact with personnel and review of microbiology and medical records. Nosocomial diarrhea was defined as loose stools occurring more than 48 hours after admission, with at least two loose stools in 12 hours and no likely non-infectious cause.

Results:

Nosocomial diarrhea was the third most common nosocomial infection (217 of 1,466; 15%), after bloodstream and respiratory infections, with from 0.5 to 1 episode per 1,000 patient-days. Of 217 nosocomial diarrhea episodes, 122 (56%) had identified pathogens:C. difficile(39 of 122; 32%), rotavirus (38 of 122; 31%), adenovirus (36 of 122; 30%), and other viral (9 of 122; 7%). The median age was 1.3 years (range, 11 days to 17.9 years), 0.80 year for children with viral diarrhea, 3.9 years for children withC. difficile, and 1.5 years for children with diarrhea without a causative organism identified (P< .0001). Most children with nosocomial diarrhea were incontinent (diapered) at the time of their first episode (138 of 185; 75%), but preexisting incontinence was more common in those with viral diarrhea (93%) compared with those with no organism identified (71%) or those withC. difficile-associated diarrhea (CDAD) (49%) (P< .0001).

Conclusions:

C. difficileis the single most common cause of nosocomial diarrhea in our tertiary-care center, although all viral pathogens account for 69% of cases. Diapered status appears to be a risk factor for CDAD in children, and CDAD occurs more often in older children than viral nosocomial diarrhea. Further characterization of risk factors for, and morbidity associated with, nosocomial CDAD in children is warranted.
An Outbreak ofSalmonellaSerotype Saintpaul in a Children's Hospital
Authors: Bornemann Rena , Zerr Danielle M. , Heath Joan , Koehler Jane , Grandjean Marcus , Pallipamu Ravi , Duchin Jeff
Published: February 2006

Objectives:

To describe a nosocomial outbreak ofSalmonellaserotype Saintpaul gastroenteritis and to explore risk factors for infection.

Design:

Case-control study.

Setting:

A 208-bed, university-affiliated children's hospital.

Participants:

Patients hospitalized at Children's Hospital and Regional Medical Center, Seattle, Washington, during February 2001 who had stool specimens obtained for culture at least 24 hours after admission. Case-patients (n = 11) were patients with an indistinguishable strain ofSalmonellaSaintpaul cultured from their stool. Control-patients (n = 41) were patients hospitalized for problems other than gastroenteritis whose stool cultures were negative forSalmonella.

Methods:

Risk factors were evaluated using the chisquare test or Fisher's exact test. Continuous variables were compared using the Mann–Whitney U test. A multivariable analysis was performed using logistic regression. The predictor of interest was the receipt of enteral feeding formula mixed by the hospital.

Results:

Case-patients were more likely than control-patients to have received formula mixed by the hospital (OR, 4.2; 95% confidence interval, 1.04 to 17.16). Other variables evaluated were not significant predictors ofSalmonellaSaintpaul infection.

Conclusions:

Formula mixed by the hospital appears to have been the source of thisSalmonellaoutbreak. Strict sanitation measures must be ensured in formula preparation and delivery, and bacterial pathogens should be included in the differential diagnosis for nosocomial gastroenteritis.
Epidemiology of Methicillin-SusceptibleStaphylococcus Aureusin the Neonatal Intensive Care Unit
Authors: Graham Philip L. , Morel Anne-Sophie , Zhou Juyan , Wu Fann , Della-Latta Phyllis , Rubenstein David , Saiman Lisa
Published: February 2006

Objective:

When the incidence of methicillin-susceptibleStaphylococcus aureus(MSSA) infection or colonization increased in our neonatal intensive care unit (NICU), we sought to further our understanding of the relationship among colonization with MSSA, endemic infection, and clonal spread.

Design:

A retrospective cohort study was used to determine risk factors for acquisition of a predominant clone of MSSA (clone “B”).

Setting:

A 45-bed, university-affiliated, level III-IV NICU.

Patients:

Infants hospitalized in the NICU from October 1999 to September 2000.

Interventions:

Infection control strategies included surveillance cultures of infants, cohorting infected or colonized infants, contact precautions, universal glove use, mupirocin treatment of the anterior nares of all infants in the NICU, and a hexachlorophene bath for infants weighing 1,500 g or more.

Results:

During the 1-year study period, three periods of increased incidence of MSSA colonization or infection, ranging from 6.4 to 13.5 cases per 1,000 patient-days per month, were observed. Molecular typing using pulsed-field gel electrophoresis demonstrated two predominant clones, clone “B” and clone “G,” corresponding to two periods of increased incidence. Multivariate analysis demonstrated that length of stay (OR, 1.035; 95% confidence interval [CI95], 1.008 to 1.062;P= .010) (increased risk per day) and the use of H2-blockers (OR, 20.44; CI95, 2.48 to 168.26;P= .005) were risk factors for either colonization or infection with clone “B,” and that the use of peripheral catheters was protective (OR, 0.06; CI95, 0.01 to 0.43;P= .005).

Conclusions:

Control of MSSA represents unique challenges as colonization is expected, endemic infections are tolerated, and surveillance efforts generally focus on multidrug-resistant pathogens. Future studies should address cost-effective surveillance strategies for endemic infections.
Effectiveness of Pharmacy Policies Designed to Limit Inappropriate Vancomycin Use: A Population-Based Assessment
Authors: Thomas Ann R. , Cieslak Paul R. , Strausbaugh Larry J. , Fleming David W.
Published: February 2006

Objective:

In Oregon in 1994, a population-based study of 66 nonpsychiatric hospitals indicated that 40% of vancomycin orders were inappropriate according to Centers for Disease Control and Prevention guidelines. We repeated the study to determine whether vancomycin use had been affected by pharmacy policies implemented following the 1994 study.

Methods:

We surveyed pharmacists in nonpsychiatric hospitals in Oregon regarding vancomycin use policies in their hospitals. Using pharmacy records, we identified and abstracted the charts of all patients in Oregon hospitals receiving vancomycin during a 3-week period to determine appropriate use of vancomycin.

Results:

Thirteen (20%) of 64 hospitals had implemented a vancomycin restriction policy since 1994; none of the remaining hospitals in the study had a policy. In 1999, hospitals with vancomycin restriction policies had substantially decreased rates of inappropriate vancomycin use compared with hospitals without such policies (1.0 vs 1.8 orders per 1,000 patient-days; P = .01). Compared with 1994 baseline rates of inappropriate use, hospitals that adopted policies experienced a decrease (from 1.5 orders per 1,000 patient-days in 1994 to 1.0 in 1999; P= .13), whereas hospitals without policies experienced a statistically significant increase (from 0.9 orders per 1,000 patient-days in 1994 to 1.8 in 1999; P =
.001). Restriction policies were most effective at reducing rates of inappropriate use for treatment of confirmed gram-positive infections and prophylaxis.

Conclusion:

Vancomycin restriction policies were associated with a decrease in inappropriate therapeutic and prophylactic vancomycin use, but had no effect on inappropriate empiric use. Hospitals considering limits regarding inappropriate use should consider implementation of institution-based vancomycin restriction policies as part of an overall strategy.
Chlorhexidine Resistance in Antibiotic-Resistant Bacteria Isolated From the Surfaces of Dispensers of Soap Containing Chlorhexidine
Authors: Brooks Steven E. , Walczak Mary A. , Hameed Rizwanullah , Coonan Patrick
Published: February 2006

Bacterial contamination with pan-resistant Acinetobacter and Klebsiella, multidrug-resistant Pseudomonas, and methicillin-resistant Staphylococcus aureus (MRSA) was noted on the surfaces of dispensers of hand soap with 2% chlorhexidine. Gram-negative isolates could multiply in the presence of 1% chlorhexidine. In contrast, MRSA was inhibited in vitro by chlorhexidine at concentrations as low as 0.0019%.
Surveillance of Hemodialysis-Associated Primary Bloodstream Infections: The Experience of Ten Hospital-Based Centers
Authors: Dopirak Margaret , Hill Connie , Oleksiw Marylee , Dumigan Diane , Arvai Jean , English Ellen , Carusillo Evelyn , Malo-Schlegel Susan , Richo Jeana , Traficanti Karen , Welch Bobbie , Cooper Brian
Published: February 2006

Objective:

To determine baseline rates of primary bloodstream infection (BSI) among a large pool of patients receiving hemodialysis using standardized surveillance tools and methodology.

Design:

Prospective, descriptive analysis of primary BSI rates.

Setting:

Ten hospital-based hemodialysis centers in Connecticut.

Patients:

All patients receiving long-term hemodialysis in the participating facilities.

Results:

A total of 158 BSIs occurred during 142,525 dialysis sessions within a 12-month study period. Of the BSIs, 15.2% occurred in patients with fistula or graft access and 84.8% in patients with central venous catheter access (P< .001). Rates per 100 patient-years in centers ranged from 0 to 30.8, with a mean of 16.6. Rates per 1,000 dialysis sessions ranged from 0 to 2.1, with a mean of 1.1. Coagulase-negative staphylococci andStaphylococcus aureus(including methicillin-resistantS. aureus) accounted for 61% andKlebsiellaorEnterobacterspecies for 14.6% of infections. Of the patients, 63.3% received vancomycin, 24.7% received cefazolin, and 41.7% received aminoglycosides. Rates declined in the second 6 months of the study from 1.4 to 0.8 infections per 1,000 dialysis sessions (P< .001).

Conclusions:

Primary BSI rates varied widely among participating centers and declined during the study period. BSIs were strongly associated with central venous catheter access. Further studies are needed to determine the reasons for variance in rates between centers and among various types of hemodialysis access.
An Outbreak of Bloodstream Infections in an Outpatient Hemodialysis Center
Authors: Price Connie S. , Hacek Donna , Noskin Gary A. , Peterson Lance R.
Published: February 2006

Objectives:

Investigate and control an increase in bloodstream infections (BSIs) in an outpatient hemodialysis center.

Patients and Design:

A retrospective cohort study was conducted for patients receiving dialysis at the center from February 2000 to April 2001. A case–control study compared microbiological data for all BSIs that occurred during the study period with those for BSIs that occurred during a baseline period Qanuary 1999 to January 2000). BSI rates before and after a 1-month intervention (May 2001) were assessed. A case was defined as a new BSI during the study period.

Results:

The outbreak was polymicrobial, with approximately 30 species. The baseline BSI rate was 0.7 per 100 patient-months. From February 2000 to April 2001, the BSI rate increased to 4.2 per 100 patient-months. Overall, 75% of the BSIs were associated with central venous catheters (CVCs), but CVC use did not fully explain the increase in BSIs. In January 2000, when the center changed ownership, prepackaged CVC dressing kits and biweekly infection control monitoring were discontinued. Beginning in May 2001, staff were educated on CVC care, chlorhexidine replaced povidone-iodine for cutaneous antisepsis, gauze replaced transparent dressings, antimicrobial ointments containing polyethylene glycol at CVC exit sites were discontinued, and patients with CVCs were educated on cutaneous hygiene. After the intervention period, by October 2001, rates decreased to less than 1 BSI per 100 patient-months.

Conclusions:

Proper cutaneous antisepsis and access site care is crucial in preventing BSIs in patients receiving hemodialysis. Infection control programs, staff and patient education, and use of optimal antisepsis agents or prepackaged kits are useful toward this end.
Weekly Transparent Dressing Changes Linked to Increased Bacteremia Rates
Authors: Curchoe Ruth M. , Powers Jeanette , El-Daher Nayef
Published: February 2006

Background:

In 2000, the rate of primary bloodstream infections (BSIs) was double that in 1999 for intensive care unit (ICU) patients with triple lumen catheters, pulmonary artery catheters, or both. In December 1999, changes in products and practices related to site care were implemented as a cost-saving initiative.

Objective:

To determine the factors contributing to an increase of BSIs after cost-saving measures for site care had been introduced.

Design:

Epidemiologic study involving prospective identification of infection.

Setting:

A community teaching hospital.

Participants:

Patients in a 20-bed, medical-surgical ICU identified as having triple lumen catheters, pulmonary artery catheters, or both and a primary BSI during 2000 and 2001.

Methods:

Alcohol swab sticks were reintroduced and the frequency of transparent dressing changes and site care was increased. Inservice presentations were conducted on aseptic technique and posters were placed reviewing site care protocol for physicians and nurses.

Results:

The incidence of primary BSIs decreased significantly (P = .003) during a 3-month intervention and this decrease was sustained through the following 12 months.

Conclusions:

Prolonging the interval between the change of transparent dressings from 3 times weekly to once weekly and switching from alcohol swab sticks to pads was associated with an increase in BSIs, which was controlled after returning to the original policy (Infect Control Hosp Epidemiol 2002;23:730-732)
SerratiaBacteremia in a Large University Hospital: Trends in Antibiotic Resistance During 10 Years and Implications for Antibiotic Use
Authors: Choi Sang-Ho , Kim Yang Soo , Chung Jin-Won , Kim Tae Hyong , Choo Eun Ju , Kim Mi-Na , Kim Baek-Nam , Kim Nam Joong , Woo Jun Hee , Ryu Jiso
Published: February 2006

Objective:

To identify antibiotic resistance trends and risk factors for resistance ofSerratiaspecies to third-generation cephalosporins.

Design:

Retrospective survey of medical records.

Setting:

A 2,200-bed, tertiary-care hospital.

Patients:

One hundred twenty-two patients withSerratiabacteremia between January 1991 and June 2001.

Methods:

Infectious disease physicians collected data from medical records regarding patient demographics, underlying disease or condition, portal of entry, microorganism, antibiogram, complications, antibiotics received, and outcome.

Results:

Among 122Serratiaisolates, 117 (95.9%) wereSerratiamarcescens and 110 (90.2%) were of nosocomial origin. During the study period, the 122 isolates showed a high rate of resistance to third-generation cephalosporins (45.9%) and extended-spectrum penicillins (56.6%). The resistance rate to ciprofloxacin was 32.0%. The resistance rate to third-generation cephalosporins increased from 31.7% for 1991 to 1995 to 54.9% for 1996 to 1998 and 50.0% for 1999 to 2001. In the multivariate analysis, prior use of a second-generation cephalosporin (adjusted odds ratio [OR], 5.90; 95% confidence interval [CI95], 1.41 to 24.6;P= .015) or a third-generation cephalosporin (OR, 3.26; CI95, 1.20 to 8.87;P= .020) was a strong independent risk factor for resistance to third-generation cephalosporins. The overall case-fatality rate was 25.4% (Serratiabacteremia-related case-fatality rate, 13.1%).

Conclusion:

Prior use of a second- or third-generation cephalosporin was the most important risk factor for bacteremia withSerratiaresistant to third-generation cephalosporins, suggesting the need for antibiotic control. The potential role of patient-to-patient spread could not be fully evaluated in this retrospective study.
Prevention of Bloodstream Infections With Central Venous Catheters Treated With Anti-Infective Agents Depends on Catheter Type and Insertion Time: Evidence From a Meta-Analysis
Authors: Walder Bernhard , Pittet Didier , Tramèr Martin R.
Published: February 2006

Objective:

To test the evidence that the risk of infection related to central venous catheters (CVCs) is decreased by anti-infective coating or cuffing.

Design:

Systematic review of randomized, controlled trials comparing anti-infective with inactive (control) CVCs.

Interventions:

Average insertion times were taken as a measurement of the length of insertion. Dichotomous data were combined using a fixed effect model and expressed as odds ratio (OR) with 95% confidence interval (CI95).

Results:

Two trials on antibiotic coating (343 CVCs) had an average insertion time of 6 days; the risk of BSI decreased from 5.1% with control to 0% with anti-infective catheters. There were no trials with longer average insertion times. In three trials on silver collagen cuffs (422 CVCs), the average insertion time ranged from 5 to 8.2 days (median, 7 days); the risk of BSI was 5.6% with control and 3.2% with anti-infective catheters. In another trial on silver collagen cuffs (101 CVCs), the average insertion time was 38 days; the risk of BSI was 3.7% with control and 4.3% with anti-infective catheters. In five trials on chlorhexidine-silver sulfadiazine coating (1,269 CVCs), the average insertion time ranged from 5.2 to 7.5 days (median, 6 days); the risk of BSI decreased from 4.1% with control to 1.9% with anti-infective catheters. In five additional trials on chlorhexidine–silver sulfadiazine coating (1,544 CVCs), the average insertion time ranged from 7.8 to 20 days (median, 12 days); the risk of BSI was 4.5% with control and 4.2% with anti-infective catheters.

Conclusions:

Antibiotic and chlorhexidine–silver sulfadiazine coatings are anti-infective for short (approximately 1 week) insertion times. For longer insertion times, there are no data on antibiotic coating, and there is evidence of lack of effect for chlorhexidine-silver sulfadiazine coating. For silver-impregnated collagen cuffs, there is evidence of lack of effect for both short- and long-term insertion.
Central Venous Catheter–Related Infection: A Prospective, Observational Study to Assess the Incidence Rate at a Teaching Hospital in Argentina
Authors: Bantar Carlos , Bustos José Luis , Vesco Eduardo , Morera Graciana ,   The Residence of Internal Program
Published: February 2006

One hundred fifty-one central venous catheters (CVCs) were observed for development of infection. The infection rate was higher for CVCs with a duration of less than 6 days than for those with a longer duration. Our data suggest that scheduled replacement of CVCs is not necessary.
Molecular Epidemiology of Methicillin–ResistantStaphylococcus Aureusin a Veterans Administration Medical Center
Authors: Herwaldt Loreen A. , Pottinger Jean M. , Coffman Stacy , Tjaden Jean
Published: February 2006

Objectives:

To determine whether patients who were colonized or infected with methicillin-resistantStaphylococcus aureus(MRSA) persistently carried the same strain and to identify the extent of strain variation within a population of patients.

Design:

Molecular typing by pulsed-field gel electrophoresis (PFGE) of stored MRSA isolates.

Setting:

A Veterans Administration Medical Center with 288 hospital, 45 intermediate-care, and 75 extended-care beds.

Isolates:

Between January 1991 and March 1993, 91 patients had MRSA identified in routine cultures. One hundred isolates from 57 patients (63%) were available for typing.

Results:

Before 1988, only occasional MRSA isolates were identified. By 1993, 50% ofS. aureusisolates from unique patients were resistant to methicillin. PFGE identified 7 MRSA strains, 3 of which were identified in specimens from 1 patient each. The most common strains were SD4 (20 patients), SD1 (12 patients), SD2 (12 patients), and SD5a (5 patients). Twenty patients had 2 or more isolates obtained at least 1 week apart (mean, 30.7 weeks; range, 1 to 102 weeks). Of these patients, 12 were colonized or infected with only one strain (mean time observed, 25.1 weeks; range, 1 to 82 weeks). Eight patients had at least 2 different strains (mean time observed, 39 weeks; range, 2 to 102 weeks).

Conclusion:

Numerous MRSA strains circulated in tiiis endemic setting; 40% of patients observed over time were colonized or infected witii more than one strain. Molecular typing was an essential tool for evaluating the epidemiology of MRSA in this setting.
Routine Screening for Methicillin-ResistantStaphylococcus AureusAmong Patients Newly Admitted to an Acute Rehabilitation Unit
Authors: Manian Farrin A. , Senkel Diane , Zack Jeanne , Meyer Lynn
Published: February 2006

Background:

Following an outbreak of methicillin-resistantStaphylococcus aureus(MRSA) infection in our acute rehabilitation unit in 1987, all patients except in-house transfers (because of their low prevalence of MRSA colonization) underwent MRSA screening cultures on admission.

Objectives:

To better characterize the current profile of patients with positive MRSA screening cultures at the time of admission to our acute rehabilitation unit, and to determine the relative yield of nares, perianal, and wound screening cultures in this population.

Methods:

Prospective chart review with ongoing active surveillance for infections associated with the acute rehabilitation unit.

Results:

The rate of MRSA isolation from one or more body sites increased significantly from 5% (1987–1988) to 12% (1999–2000) (P= .0009) for newly admitted patients and from 0% to 7% (P< .0001) for in-house transfers. A negative nares culture was highly predictive (98%) of a negative perianal culture. Prior history of MRSA infection or colonization and transfer from outside sources were independently associated with positive MRSA screening cultures.

Conclusion:

The rate of MRSA isolation from screening cultures of newly admitted patients, including in-house transfers, has increased significantly during the past decade in our acute rehabilitation unit. When paired with nares cultures, perianal cultures were of limited value in this patient population.
The Ability of Hospital Ventilation Systems to FilterAspergillusand Other Fungi Following a Building Implosion
Authors: Srinivasan Arjun , Beck Christopher , Buckley Timothy , Geyh Allison , Bova Greg , Merz William , Perl Trish M.
Published: February 2006

Objectives:

To assess the ability of hospital air handling systems to filterAspergillus, other fungi, and particles following the implosion of an adjacent building; to measure the quantity and persistence of airborne fungi and particles at varying distances during a building implosion; and to determine whether manipulating air systems based on the movement of the dust cloud would be an effective strategy for managing the impact of the implosion.

Design:

Air sampling study.

Setting:

A 976-bed teaching hospital in Baltimore, Maryland.

Methods:

Single-stage impactors and particle counters were placed at outdoor sites 100, 200, and 400 m from the implosion and in five locations in the hospital: two oncology floors, the human immunodeficiency virus unit, the cardiac surgical intensive care unit, and the ophthalmology unit. Air handling systems would operate normally unless the cloud approached the hospital.

Results:

Wind carried the bulk of the cloud away from the hospital.Aspergilluscounts rose more than tenfold at outdoor locations up to 200 m from the implosion, but did not increase at 400 m. Total fungal counts rose more than sixfold at 100 and 200 m and twofold at 400 m. Similar toAspergillus, particle counts rose several-fold following the implosion at 100 and 200 m, but did not rise at 400 m. No increases in any fungi or particles were measured at indoor locations.

Conclusion:

Reacting to the movement of the cloud was effective, because normal operation of the hospital air handling systems was able to accommodate the modest increase inAspergillus, other fungi, and particles generated by the implosion.Aspergillusmeasurements were paralleled by particle counts.
Efficacy of High-Efficiency Particulate Air Filtration in Preventing Aspergillosis in Immunocompromised Patients With Hematologic Malignancies
Authors: Hahn Theresa , Cummings K. Michael , Michalek Arthur M. , Lipman Brian J. , Segal Brahm H. , McCarthy Philip L.
Published: February 2006

Objectives:

To describe and investigate the cause of an outbreak of 10 cases of nosocomial invasive infection withAspergillus flavusin a hematologic oncology patient care unit.

Design:

A retrospective cohort study.

Setting:

The hematologic oncology unit of a comprehensive cancer center.

Patients:

Ninety-one patients admitted to the hematologic oncology service between January 1 and December 31,1992, for 4 or more consecutive days were included in the study.

Results:

Ten (18%) of 55 patients admitted from July to December 1992 were diagnosed as having invasive aspergillosis compared with 0 (0%) of 36 patients admitted from January to June 1992 to the same patient care units. Patient characteristics, mortality rate, autopsy rate, and admitting location did not change significantly during the course of the year to result in a sudden increase in the number of aspergillosis cases. The source of the outbreak was the high counts ofAspergillusconidia determined from air sampling in the non–bone marrow transplant wing during the outbreak. After high-efficiency particulate air (HEPA) filters were installed as an infection control measure, there were only two additional cases of nosocomial aspergillosis in the 2 years following the outbreak.

Conclusions:

This outbreak occurred among hematologic oncology patients with prolonged granulocytopenia housed in an environment with neither HEPA filters nor laminar air flow units. Our data demonstrate that in the setting of an outbreak of aspergillosis, HEPA filters are protective for highly immunocompromised patients with hematologic malignancies and are effective at controlling outbreaks due to air contamination withAspergillusconidia.
Epidemiology, Molecular Mycology, and Environmental Sources ofFusariumInfection in Patients with Cancer
Authors: Raad Issam , Tarrand Jeffrey , Hanna Hend , Albitar Maher , Janssen Erle , Boktour Maha , Bodey Gerald , Mardani Masoud , Hachem Ray , Kontoyiannis Dimitrios , Whimbey Estella , Rolston Kenneth
Published: February 2006

Objective:

To investigate the epidemiology and environmental sources of Fusarium infections in patients with cancer.

Design:

Retrospective case-control study conducted following surveillance environmental cultures and DNA analysis of isolated organisms.

Setting:

A tertiary-care, university cancer center.

Methods:

In 1996 and 1997, environmental cultures were performed on air samples and water systems. A retrospective chart review was performed for 70 patients with cancer identified with fusariosis between 1987 and 1997. Patients with fusariosis were compared with 49 uninfected control patients who occupied hospital rooms with positive environmental cultures for Fusarium. With the use of random amplification of polymorphic DNA organisms isolated from infected patients were compared with environmental organisms.

Results:

Most of the patients with Fusarium (40, 57%) were infected on or within 3 days of admission, indicating community rather than nosocomial acquisition. Patients were comparable in terms of underlying immunocompromised status to 49 uninfected control patients. However, the duration from admission to infection in the patients with fusariosis tended to be shorter than the duration from admission to discharge in the exposed control patients (P= .06). Water cultured from the hospital tanks and from sinks and water fountains was negative for Fusarium. With the use of polymerase chain reaction, environmental isolates did not match clinical ones. Quantitative air sampling showed that the quantitative outdoor Fusarium levels were eightfold higher than the indoor levels. During the rainy summer season, outdoor air concentrations of Fusarium were at their highest, coinciding with the peak incidence of fusariosis at our center.

Conclusion:

The most likely source of fusariosis was the external environment rather than nosocomial sources, such as water.
Molecular Epidemiology of Methicillin-ResistantStaphylococcus aureusin Nursing Homes: A Cross-Sectional Study
Authors: Hoefnagels-Schuermans Annette , Niclaes Luc , Buntinx Frank , Suetens Carl , Jans Beatrice , Verhaegen Jan , Eldere Johan Van
Published: February 2006

A cross-sectional study of methicillin-resistantStaphylococcus aureuscarriage in 2,857 nursing home residents showed an overall prevalence of 4.9%. The three clones identified by genetic analysis were identical to those in the acute care facilities; only their relative prevalence differed. Clone 2 took epidemic proportions in five of these nursing homes.
Thioredoxin-mediated Negative Autoregulation of Peroxisome Proliferator-activated Receptor α Transcriptional Activity
Authors: Liu Guang-Hui , Qu Jing , Shen Xun
Published: February 2006

PPARα, a member of the nuclear receptor superfamily, and thioredoxin, a critical redox-regulator in cells, were found to form a negative feedback loop, which autoregulates transcriptional activity of PPARα. Thioredoxin was identified as a target gene of PPARα. Activation of PPARα leads to increase of thioredoxin expression as well as its translocation from cytoplasm to nucleus, whereas ectopic overexpression of thioredoxin in the nucleus dramatically inhibited both constitutive and ligand-dependent PPARα activation. As PPARα-target genes, the expression of muscle carnitine palmitoyltransferase I, medium chain acyl CoA dehydrogenase, and apolipoprotein A-I were significantly down-regulated by nucleus-targeted thioredoxin at transcriptional or protein level. The suppression of PPARα transcriptional activity by Trx could be enhanced by overexpression of thioredoxin reductase or knockdown of thioredoxin-interacting protein, but abrogated by mutating the redox-active sites of thioredoxin. Mammalian one-hybrid assays showed that thioredoxin inhibited PPARα activity by modulating its AF-1 transactivation domain. It was also demonstrated by electrophoretic mobility-shift assay that thioredoxin inhibited the binding of PPARα to the PPAR-response element. Together, it is speculated that the reported negative-feedback loop may be essential for maintaining the homeostasis of PPARα activity.
Bacterial nucleoid dynamics: oxidative stress response in Staphylococcus aureus
Authors: Morikawa Kazuya , Ohniwa Ryosuke L. , Kim Joongbaek , Maruyama Atsushi , Ohta Toshiko , Takeyasu Kunio
Published: February 2006

A single‐molecule‐imaging technique, atomic force microscopy (AFM) was applied to the analyses of the genome architecture of Staphylococcus aureus. The staphylococcal cells on a cover glass were subjected to a mild lysis procedure that had maintained the fundamental structural units in Escherichia coli. The nucleoids were found to consist of fibrous structures with diameters of 80 and 40 nm. This feature was shared with the E. coli nucleoid. However, whereas the E. coli nucleoid dynamically changed its structure to a highly compacted one towards the stationary phase, the S. aureus nucleoid never underwent such a tight compaction under a normal growth condition. Bioinformatic analysis suggested that this was attributable to the lack of IHF that regulate the expression of a nucleoid protein, Dps, required for nucleoid compaction in E. coli. On the other hand, under oxidative conditions, MrgA (a staphylococcal Dps homolog) was over‐expressed and a drastic compaction of the nucleoid was detected. A knock‐out mutant of the gene encoding the transcription factor (perR) constitutively expressed mrgA, and its nucleoid was compacted without the oxidative stresses. The regulatory mechanisms of Dps/MrgA expression and their biological significance were postulated in relation to the nucleoid compaction.
5′‐Adenosinephosphosulphate reductase (CysH) protects Mycobacterium tuberculosis against free radicals during chronic infection phase in mice
Authors: Senaratne Ryan H. , De Silva A. Dharshan , Williams Spencer J. , Mougous Joseph D. , Reader J. Rachel , Zhang Tianjiao , Chan Stephen , Sidders Ben , Lee Dong H. , Chan John , Bertozzi Carolyn R. , Riley Lee W.
Published: February 2006

A major obstacle to tuberculosis (TB) control is the problem of chronic TB infection (CTBI). Here we report that 5′‐adenosinephosphosulphate reductase (CysH), an enzyme essential for the production of reduced‐sulphur‐containing metabolites, is critical for Mycobacterium tuberculosis (Mtb) survival in chronic infection phase in mice. Disruption of cysH rendered Mtb auxotrophic for cysteine and methionine, and attenuated virulence in BALB/c and C57BL/6 immunocompetent mice. The mutant and wild‐type Mtb replicated similarly during the acute phase of infection, but the mutant showed reduced viability during the persistent phase of the infection. The cysH mutant caused disease and death after 4–7 weeks of infection in four different groups of mice – Rag1–/–, NOS2–/–, gp91phox–/– NOS2–/– and gp91phox–/– mice given aminoguanidine [to suppress the effects of nitric oxide synthase 2 (NOS2)]– indicating minimal metabolic effect on the cysH mutant survival in these mice. The cysH mutant was also susceptible to peroxynitrite and hydrogen peroxide in vitro. These results show that CysH is important for Mtb protection during the chronic infection phase, and that resistance to nitrosative and oxidative stress may be the mechanism of this protection. Thus, this metabolic gene of an intracellular pathogen could have a secondary role in protection against the host immune response. Finally the lack of an endogenous human orthologue of cysH and its possible role in defence against adaptive immunity renders CysH an attractive enzyme for further studies as a target for therapeutics active against CTBI.
Poly(A)‐polymerase I links transcription with mRNA degradation via σS proteolysis
Authors: Santos Jorge M. , Freire Patrick , Mesquita Francisco S. , Mika Franziska , Hengge Regine , Arraiano Cecília M.
Published: February 2006

Bacteria rapidly adapt to changes in growth conditions through control of transcription and specific mRNA degradation. Interplay of both mechanisms must exist in order to achieve fine‐tuned regulation of gene expression. Transcription of the Escherichia coli bolA gene is mediated by the RpoS/σS transcription factor in response to environmental signals. In this report it is shown that the mechanisms of bolA1p mRNA transcription and degradation are tightly connected at the onset of stationary phase and in response to sudden carbon starvation. In stationary phase, bolA1p mRNA levels were reduced 2.5‐fold in a poly(A)‐polymerase I (PAPI) mutant, explained by the significant threefold reduction in σS protein levels in the same strain. Furthermore, fusions with the rpoS gene, analysis of the stability of σS and the levels of RssB indicate that the absence of PAPI enhances RssB‐mediated σS proteolysis specifically in starved cells. The fact that PAPI induces higher cellular levels of a global regulator is a novel finding of wide biological significance. PAPI could work as a linker between transcription and mRNA degradation with the ultimate goal of adapting and surviving to growth‐limiting conditions.
Drastic reduction in the virulence of Streptococcus pneumoniae expressing type 2 capsular polysaccharide but lacking choline residues in the cell wall
Authors: Kharat Arun S. , Tomasz Alexander
Published: February 2006

The role of capsular polysaccharides and several virulence‐related proteins in the pathogenic potential of Streptococcus pneumoniae has been studied extensively. Much less information is available about the role of the pneumococcal cell wall in virulence. In this communication we describe an experimental system that has allowed us to test – in a global way – the role of choline, a structural component of the pneumococcal cell wall, in virulence. We constructed double mutants of S. pneumoniae which have lost the auxotrophic requirement for choline and which were also blocked from utilizing choline from the growth medium. Such a double mutant expressing type 2 capsule but completely lacking choline residues from its cell wall grew well both in vitro and also in the blood of infected mice, but showed striking reduction of virulence approaching that of a capsule‐free strain in several models of pneumococcal disease including the capacity to attach and invade a human nasopharyngeal cell line; nasal colonization and intraperitoneal and intravenous inoculation in the mouse. The findings allow one to separate the choline requirement of S. pneumoniae into two sharply defined classes: the need for choline in growth and replication which can be effectively bypassed and the need for choline in pneumococcal virulence that appears to be irreplaceable. The double mutant should be a useful experimental tool to dissect the mechanism of choline requirement in various stages of pneumococcal virulence.
The role of replication initiation control in promoting survival of replication fork damage
Authors: Sutera Vincent A. , Lovett Susan T.
Published: February 2006

Dam methylase mutants were recovered in a screen for mutants sensitive to UV irradiation or mild inhibition of replication elongation. Dam's role in tolerance of DNA damage is to provide binding sites for SeqA, because seqA mutants showed similar sensitivity that was genetically epistatic to dam. The sensitivity of seqA mutants to UV irradiation and to the replication inhibitors hydroxyurea (HU) and azidothymidine (AZT) was suppressed by alleles of dnaA that reduce the efficiency of replication initiation. These results suggest that for survival of replication fork damage, SeqA's repression of replication initiation is more important than its effects on nucleoid organization. Convergence of forks upon DNA damage is a likely explanation for seqA mutant sensitivity, because its poor survival of UV was suppressed by reducing secondary initiation through minimal medium growth. Surprisingly, growth in minimal medium reduced the ability of seqA+ strains to form colonies in the presence of low levels of AZT. Double dnaA seqA mutants exhibited plating efficiencies much superior to wild‐type strains during chronic low‐level AZT exposure in minimal medium. This suggests that mild inhibition of replication fork progression may actively restrain initiation such that seqA+ strains fail to recover initiation capacity after sustained conditions of replication arrest.
Freeze/thaw‐induced embolism depends on nadir temperature: the heterogeneous hydration hypothesis
Authors: BALL M. C. , CANNY M. J. , HUANG C. X. , EGERTON J. J. G. , WOLFE J.
Published: February 2006

Freeze/thaw‐induced embolism was studied in leaves of field‐grown snow gum (Eucalyptus pauciflora) subject to frequent morning frosts. Juvenile trees were grown in buried pots, brought to the laboratory at different stages of acclimation and subjected to simulated frost‐freezes (at 2 °C h−1) to nadir temperatures of −3 or − 6 °C, which snow gums commonly experience. Frost‐frozen and subsequently thawed leaves were cryo‐fixed to preserve the distribution of water and were then examined by cryo‐scanning electron microscopy. No embolisms were found in leaves frozen to −3 °C and thawed. In contrast, 34% of vessels were embolized in thawed leaves that had been frozen to −6 °C. This difference was seen also in the extent of extracellular ice blocks in the mid‐vein expansion zones in leaves frozen to −3 and −6 °C, which occupied 3 and 14% of the mid‐vein area, respectively. While the proportion of embolism depended on nadir temperature, it was independent of season (and hence of acclimation state). From the observation that increased embolism at lower nadir temperature was related to the freeze‐induced redistribution of water, we hypothesize that the dehydration of cell walls and cells caused by the redistribution exerts sufficient tension on xylem water to induce cavitation on thawing.
Interactions between the effects of atmospheric CO2 content and P nutrition on photosynthesis in white lupin (Lupinus albus L.)
Authors: CAMPBELL CATHERINE D. , SAGE ROWAN F.
Published: February 2006

Phosphorus (P) is a major factor limiting the response of carbon acquisition of plants and ecosystems to increasing atmospheric CO2 content. An important consideration, however, is the effect of P deficiency at the low atmospheric CO2 content common in recent geological history, because plants adapted to these conditions may also be limited in their ability to respond to further increases in CO2 content. To ascertain the effects of low P on various components of photosynthesis, white lupin (Lupinus albus L.) was grown hydroponically at 200, 400 and 750 µmol mol−1 CO2, under sufficient and deficient P supply (250 and 0.69 µm P, respectively). Increasing growth CO2 content increased photosynthesis only under sufficient growth P. Ribulose 1,5‐biphosphate carboxylase/oxygenase (Rubisco) content and activation state were not reduced to the same degree as the net CO2 assimilation rate (A), and the in vivo rate of electron transport was sufficient to support photosynthesis in all cases. The rate of triose phosphate use did not appear limiting either, because all the treatments continued to respond positively to a drop in oxygen levels. We conclude that, at ambient and elevated CO2 content, photosynthesis in low‐P plants appears limited by the rate of ribulose biphosphate (RuBP) regeneration, probably through inhibition of the Calvin cycle. This failure of P‐deficient plants to respond to rising CO2 content above 200 µmol mol−1 indicates that P status already imposes a widespread restriction in plant responses to increases in CO2 content from the pre‐industrial level to current values.
Clinical guidelines to diagnose smear‐negative pulmonary tuberculosis in Pakistan, a country with low‐HIV prevalence
Authors: Siddiqi Kamran , Walley J. , Khan M. A. , Shah K. , Safdar N.
Published: February 2006

Objectives  To develop and validate clinical guidelines for diagnosis of smear‐negative pulmonary tuberculosis (TB) in developing countries with low‐HIV prevalence.

Methods  We developed diagnostic guidelines for smear‐negative TB. Clinical diagnoses based on these guidelines were compared with sputum culture, chest X‐rays and reports of an expert panel.

Results  The guidelines achieved a sensitivity of 0.59 [confidence interval (CI) 0.46–0.66] and a specificity of 0.86 (CI 0.84–0.88) in diagnosing smear‐negative TB. A total of 6.8% of patients who initially improved after a course of antibiotics were later confirmed to have TB. Clinicians detected an abnormal chest X‐ray in 92% (CI 88–96%) and radiological signs of pulmonary TB in 98% (CI 94–100%) of cases.

Conclusions  Our experience highlights a number of dilemmas faced in developing, testing and implementing diagnostic guidelines in poorly resourced conditions. Using radiological criteria for TB and appropriate training can help in improving the diagnostic skills of primary care clinicians working in low‐HIV settings with access to X‐ray facilities. But a significant number of apparently smear‐negative TB cases may in fact be smear positive and TB programmes should focus on improving the quality of direct acid‐fast bacilli microscopy. The value of an antibiotic trial is questionable due to the relatively large number of false negatives generated by this approach.
The spectrum of hypoxaemia in children admitted to hospital in The Gambia, West Africa
Authors: Junge Sonja , Palmer Ayo , Greenwood Brian M. , Kim Mulholland E. , Weber Martin W.
Published: February 2006

Objective  Hypoxia predicts mortality in children with acute lower respiratory infections (ALRIs). We investigated the prevalence and predictive value of hypoxia in ALRI and other acute infectious diseases.

Methods  We studied the spectrum of hypoxaemia in 4047 children admitted to a tertiary hospital in The Gambia. Oxygen saturation was measured shortly after admission. Severe hypoxaemia was defined as an oxygen saturation below 90%.

Results  5.8% of all admissions had severe hypoxaemia. Prevalence of hypoxaemia varied between disease groups: it was 11.7% in ALRI cases, 16.5% in neonates; 2.9% in malaria cases overall but 6.5% in cerebral malaria patients; and 2.7% in children with meningitis. Hypoxaemia predicted a poor outcome; the odds ratio for death among paediatric admissions overall was 7.45 [95% confidence intervals (CI) 5.40–10.29]. Surprisingly, it was lowest for children with ALRI [OR 3.53 (95% CI 1.13–10.59)], and higher for those with malaria 9.90 [95% CI 4.39–22.35].

Conclusion  Hypoxaemia is common among Gambian children admitted to hospital and it is often associated with a poor outcome. A similar situation is likely in many other developing countries. Thus, equipment for measuring oxygen saturation, and facilities and equipment for effective oxygen delivery need to be made available in developing countries.