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Dive into the research topics where Andrew Streifel is active.

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Featured researches published by Andrew Streifel.


Infection Control and Hospital Epidemiology | 2004

AN OUTBREAK OF BACTEREMIAS ASSOCIATED WITH MYCOBACTERIUM MUCOGENICUM IN A HOSPITAL WATER SUPPLY

Susan Kline; Sarah Cameron; Andrew Streifel; Mitchell A. Yakrus; Frank Kairis; Keith Peacock; John Besser; Robert C. Cooksey

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 patients blood isolate and an isolate from shower water from that patients 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.


Infection Control and Hospital Epidemiology | 2000

Refinements of environmental assessment during an outbreak investigation of invasive aspergillosis in a leukemia and bone marrow transplant unit.

Chloe L. Thio; Dottie Smith; William G. Merz; Andrew Streifel; Greg Bova; Carole B. Miller; Trish M. Perl

OBJECTIVES To investigate an outbreak of aspergillosis in a leukemia and bone marrow transplant (BMT) unit and to improve environmental assessment strategies to detect Aspergillus. DESIGN Epidemiological investigation and detailed environmental assessment. SETTING A tertiary-care university hospital with a 37-bed leukemia and BMT unit PARTICIPANTS Leukemic or BMT patients with invasive aspergillosis identified through prospective surveillance and confirmed by chart review. INTERVENTIONS We verified the diagnosis of invasive fungal infection by reviewing medical charts of at-risk patients, performing a case-control study to determine risk factors for infection, instituting wet mopping to clean all floors, providing N95 masks to protect patients outside high-efficiency particulate air (HEPA)-filtered areas, altering traffic patterns into the unit, and performing molecular typing of selected Aspergillus flavus isolates. To assess the environment, we verified pressure relationships between the rooms and hallway and between buildings, and we compared the ability of large-volume (1,200 L) and small-volume (160 L) air samplers to detect Aspergillus spores. RESULTS Of 29 potential invasive aspergillosis cases, 21 were confirmed by medical chart review. Risk factors for developing invasive aspergillosis included the length of time since malignancy was diagnosed (odds ratio [OR], 1.0; P=.05) and hospitalization in a patient room located near a stairwell door (OR, 3.7; P=.05). Two of five A. flavus patient isolates were identical to one of the environmental isolates. The pressure in most of the rooms was higher than in the corridors, but the pressure in the oncology unit was negative with respect to the physically adjacent hospital; consequently, the unit acted essentially as a vacuum that siphoned non-HEPA-filtered air from the main hospital. Of the 78 samples obtained with a small-volume air sampler, none grew an Aspergillus species, whereas 10 of 40 cultures obtained with a large-volume air sampler did. CONCLUSIONS During active construction, Aspergillus spores may have entered the oncology unit from the physically adjacent hospital because the air pressure differed. Guidelines that establish the minimum acceptable pressures and specify which pressure relationships to test in healthcare settings are needed. Our data show that large-volume air samples are superior to small-volume samples to assess for Aspergillus in the healthcare environment.


Infection Control and Hospital Epidemiology | 2001

An Evaluation of Hospital Special-Ventilation-Room Pressures

Nancy Rice; Andrew Streifel; Donald Vesley

OBJECTIVE To quantitate the magnitude and consistency of positive (airflow out) and negative (airflow in) hospital special-ventilation-room (SVR) airflow. DESIGN A room-pressure evaluation was conducted during two seasons on a total of 18 rooms: standard rooms, airborne infection isolation rooms, and protective environment rooms. The pressures were measured using a digital pressure gauge-piezoresistive pressure sensor that measured pressure differentials. With doors closed, the rooms were measured a minimum of 30 times each for a cooling season and a heating season. RESULTS The standard rooms showed the least amount of variability in pressure differential, with an average of -0.2 Pa (median, -0.2 Pa), and an interquartile range (IQR) of 0.4 Pa. Airborne infection isolation rooms showed more variability in pressure, with an average of -0.3 Pa (median, -0.2 Pa) and an IQR of 0.5 Pa. Protective environment rooms had the greatest fluctuation in pressure, with an average of 8.3 Pa (median, 7.7 Pa) and an IQR of 8.8 Pa. Dramatic pressure changes were observed during this evaluation, which may have been influenced by room architectural differences (sealed vs unsealed); heating, ventilation, and air-conditioning zone interactions; and stack effect. CONCLUSION The pressure variations noted in this study, which potentially affect containment or exclusion of contaminants, support the need for standardization of pressure requirements for SVRs. To maintain consistent pressure levels, creating an airtight seal and continuous pressure monitoring may be necessary.


Infection Control and Hospital Epidemiology | 1986

Bubbling humidifiers produce microaerosols which can carry bacteria.

Frank S. Rhame; Andrew Streifel; Carter McComb; Mike Boyle

It is widely held that bubbling humidifiers do not produce microaerosols, although prior studies have resulted in conflicting evidence. We have studied this phenomenon in a clean room using an airborne particle counter and samplers for airborne bacteria. At gas flow rates between 10 and 80 L/min, a Cascade 1 humidifier produced between 460 and 999 water droplets/L humidified gas. Total water volume aerosolized was approximately 10(-8) ml/L humidified gas. Seventy-three percent of the particles had diameters between 1 and 5 microns. With the reservoir containing 6.4 X 10(6) P. aeruginosa/ml, it produced between 2 and 9 P. aeruginosa/L humidified gas. Most of the bacteria were in particles of a size likely to be deposited in the lung. This bacterial carry-over was between 20 and 150 times the amount predicted by multiplication of the water volume aerosolized times the concentration of bacteria in the humidifier reservoir. An Air Life humidifier produced fewer particles which were also of a size likely to be deposited in the lung and, when the reservoir contained P. aeruginosa, it aerosolized bacteria. Wick-type humidifiers did not produce detectable aerosol or bacterial carry-over. Although the clinical significance of these findings has not been established, they provide a rationale for the CDC recommendations for procedures designed to keep bubbling humidifier reservoir water uncontaminated.


Environment International | 1989

Control of airborne fungal spores in a university hospital

Andrew Streifel; Donald Vesley; F.S. Rhame; B. Murray

Abstract A new university hospital was designed to maximize the air quality protection of severely compromised patients undergoing transplantation or treatment for malignant disorders. The entire hospital was designed as a sealed building with two filter systems having >95% efficiencies for 1.0 μm particles. Controlled airflow and isolation of the most severely compromised patients were also design features. Air quality monitoring of particles and airborne fungi demonstrate effective control in the patient environment. The results show the areas with the greatest control of personnel and air changes have the lowest airborne concentrations of fungi and the smallest particles. Larger indoor airborne particle ranking indicate highest levels depending on local human activity, air change rates, or filtration efficiency.


Pediatric Infectious Disease Journal | 2014

Rapidly growing mycobacteria among pediatric hematopoietic cell transplant patients traced to the hospital water supply

Pui Ying Iroh Tam; Susan Kline; John E. Wagner; Amanda Guspiel; Andrew Streifel; Ginger Ward; Keith Messinger; Patricia Ferrieri

Background: Rapidly growing mycobacteria (RGM) have a predilection for those with immunocompromised states. We report increased isolation of RGM among pediatric hematopoietic cell transplant patients that was traced to the hospital water supply. Methods: Cases of RGM-positive patients were differentiated based on whether they were community-acquired or nosocomial, colonized or infected based on predefined criteria. Medical records of all RGM-positive patients were reviewed and data extracted. Infection control outbreak measures were instituted and an environmental investigation was conducted. Results: Between July 2011 and April 2012, 16 RGM isolates were identified among 15 hematopoietic cell transplant patients, compared with none in the preceding year. After environmental samples were initially grown on media for heterotrophic counts and further speciated, RGM species were identified in the hospital water supply. Conclusions: This outbreak of RGM was traced to an environmental source and was successfully controlled through institution of infection control measures.


Indoor and Built Environment | 2011

Airborne Infection Isolation Rooms – A Review of Experimental Studies

Marko Hyttinen; Anna Rautio; Pertti Pasanen; Tiina Reponen; G. Scott Earnest; Andrew Streifel; P. Kalliokoski

Ventilation guidelines for airborne infection isolation rooms (AIIRs) are highly variable in different countries indicating lack of actual knowledge about the guidance needed. However, US guidelines for AIIRs are extensive and have been widely adopted outside the US. AIIR performance has also been evaluated in numerous studies. For a long time, the aim has mainly been to evaluate how well the existing AIIRs meet US guidelines. For historical reasons, mixing-type ventilation has been emphasised and attention has been paid to air exchange rates, although the use of auxiliary devices, such as portable room-air cleaners and ultraviolet germicidal irradiation systems, has also been examined. Recently, the scope of the investigations has been widened. The most crucial issue is to minimise the potential for disease transmission and prevent the escape of contaminated air from the AIIR. Airflow direction inside the AIIR is also important and AIIRs minimise air leakage to save energy. On the other hand, it has been observed that efficient containment can be achieved even by using simple and inexpensive construction by considering pressure differential and air flow patterns. Nevertheless, additional research is needed to assist hospitals with improving their preparedness to cope with the threat of pandemics by building and using effective AIIRs.


American Journal of Infection Control | 1995

The effects of circuit and humidifier type on contamination potential during mechanical ventilation: A laboratory study

Ian J. Gilmour; Michael Boyle; Andrew Streifel; R.Carter McComb

BACKGROUND This study was undertaken because of concerns that ventilator humidifiers could be exacerbating the problem of nosocomial pneumonia in patients receiving mechanical ventilation. METHODS Four different brands of humidifiers were used in conjunction with a siemens Servo 900B mechanical ventilator (Siemens Life Support Services, Solna, Sweden). In the first part, the ventilator was operated with humidifiers filled with contaminated water at room temperature. The viability of airborne particles and the effect of flow rates on the number of particles produced were assessed. In the second part, we measured the effect of time and temperature on bacterial survival in humidifier chambers. Because only bubble-through humidifiers were determined to produce infectious particles, the speed with which a contaminated bubble-through humidifier could infect circuit condensate was also determined. Aliquots of chamber water and circuit condensate, as well as air samples and distal circuit swabs, were cultured. RESULTS Humidifiers other than bubble-through humidifiers did not produce aerosols. Particle production by bubble-through humidifiers varied directly with flow rate (R2 = 0.91). Chamber temperatures did not affect chamber colony counts except in bubble-through humidifiers. Although chamber colony counts in bubble-through humidifiers decreased with time, organisms remained viable throughout the study. When bubble-through humidifiers were heated, both condensate and effluent gas became heavily contaminated within minutes of flow initiation. CONCLUSIONS Bubble-through humidifiers produce aerosols that readily contaminate both circuit condensate and effluent gas. Avoiding bubble-through humidifiers should improve patient safety while allowing changes in practice that can result in significant cost savings.


Nephron | 1975

The Bacteriological Quality of Hemodialysis Solution as Related to Several Environmental Factors

James Lauer; Andrew Streifel; Carl M. Kjellstrand; Roger DeRoos

The bacterial concentrations of the municipal water increased by more than 39-fold when subjected to reverse osmosis; then decreased by greater than 200-fold within the reservoir and water supply system of the hemodialysis center. The bacterial concentrations of dialysate solutions in contact with proportioning single-pass artificial kidney machines were as low or lower than the water from the hemodialysis center system (less than 10 CFU/100 ml.). The complete opposite was observed in the recirculating single-pass artificial kidney machines where bacterial concentrations in the dialysate solution reached levels greater than 1.0 X 10(6) CFU/100 ml.


Infection Control and Hospital Epidemiology | 2002

In with the good air

Andrew Streifel

The almost continuous reconstruction of healthcare facilities challenges the safety of patients because of the continual occupancy of hospitals. Traditional safety measures during construction have focused on avoiding hazards such as fire, mineral dust, and chemical aerosols. Since the development of transplant technology and other immunosuppressive therapies, opportunistic pathogens have become more frequent nosocomial pathogens. Immunocompromised patients are often devastated by infections, which can result in death. The removal of existing buildings to make way for new healthcare facilities and the renovation of existing buildings can result in aerosolization of such pathogens. In this issue of Infection Control and Hospital Epidemiology, Srinivasan et al.1 describe the generation of a tremendous dust cloud caused by explosive demolition. Their article provides data verifying that safety measures worked during a massive potential exposure to airborne contaminants. Before this demolition project, Thio et al.2 had described an outbreak of aspergillosis due to deficiencies in building ventilation systems at the same institution. Correcting these deficiencies was paramount to ensuring air quality during this subsequent demolition. In 1983, Streifel et al.3 described an explosive demolition at the University of Minnesota in preparation for renewal of the old hospital. The 1983 protective measures involved ventilation manipulation and building protection for areas housing immunocompromised patients. Srinivasan et al. used ventilation management methods that required continuous operation of ventilation systems so as to ensure building pressure. Except for smoke management, the importance of building depressurization was relatively unknown in 1983. Building depressurization seems to be an undiscovered problem in healthcare facilities and is dependent on continuous air balance considerations for mechanical ventilation. For example, it is easier to add exhaust systems to a building than to increase the supply air. This fact has contributed to the tendency of buildings to become depressurized, making it easier for unfiltered air to enter. Since 1947, hospitals have been required to meet ventilation standards set forth in the Hill Burton Act, which distributed funds to assist in the construction of hospitals. Since then, the ventilation parameters have been developed to provide guidance to enhance the comfort and safety of the occupants of healthcare facilities. Currently, the American Institute of Architects (AIA) provides the design guidelines for construction in healthcare facilities.4 These guidelines address filter efficiency, air exchanges, and pressure management as factors necessary for the control of air quality. They are used by more than 40 states in developing design criteria for construction projects. Since 1996, the construction section of these guidelines has required the incorporation of features that facilitate infection control. Prior to 1996, construction management and design concerns were largely associated with controlling odors and mineral dust and engineering design concepts were associated with temperature and humidity control. The guidelines for construction in healthcare facilities provide a focus on the construction and ventilation management specifications for general and specific hospital mechanical systems. In another article in this issue of Infection Control and Hospital Epidemiology, Hahn et al.5 describe the addition of high-efficiency particulate air (HEPA) filters for preventing aspergillosis. Although HEPA filters are important, their installation is relatively complex and requires extensive engineering design for appropriate control of fungal spores. To install HEPA filters, it is necessary to increase fan size to drive the increase in static pressure due to an increase in filter efficiency. For example, in the outbreak described by Thio et al., the healthcare facility had been using HEPA filters, but the lack of building pressurization circumvented their value by allowing unfiltered air to enter the building through pathways other than the intakes of the air handling system.2 Therefore, it would be prudent for a protective environment (PE) to be pressurized in order to prevent the infiltration of unwanted airborne particles into susceptible patient care areas. The AIA has identified special ventilation (SPV) areas requiring specific pressurization, air exchanges, and filtration for infection control as special ventilation rooms, including airborne infection iso-

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Susan Kline

University of Minnesota

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Anthony R. Sambol

University of Nebraska Medical Center

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