Biomedical subjects

William Merz

Publications and source records attributed to William Merz.

5 recordsLinked to original sources

PubMed2003

An outbreak of Pseudomonas aeruginosa infections associated with flexible bronchoscopes.

BACKGROUND: Endoscopes, including bronchoscopes, are the medical devices most frequently associated with outbreaks of nosocomial infections. We investigated an outbreak of Pseudomonas aeruginosa infections after bronchoscopic procedures. METHODS: Microbiologic results were reviewed to determine the rates of recovery of P. aeruginosa from bronchoalveolar-lavage specimens. Environmental samples from endoscopes and the endoscopy suite were cultured. Medical records were reviewed to identify infections in the 14 days after a bronchoscopy. RESULTS: The rate of recovery of P. aeruginosa from bronchoalveolar-lavage specimens obtained with use of endoscopy-suite bronchoscopes increased from 10.4 percent at base line to 31.0 percent during the outbreak (relative risk, 2.97; 95 percent confidence interval, 2.28 to 3.90). Cultures of samples from three bronchoscopes grew P. aeruginosa, whereas cultures of samples from the environment, instrument-cleaning machines, and gastrointestinal endoscopes did not. The three bronchoscopes had been part of a nationwide recall. A total of 414 patients underwent bronchoscopy during the outbreak, and there were 48 respiratory tract and bloodstream infections among 39 of these patients (9.4 percent). In 32 infections (66.7 percent), P. aeruginosa was confirmed as a potentially causative organism. Exposure to a potentially contaminated bronchoscope may have had a role in the death of three patients. The rate of recovery of P. aeruginosa returned to base line after the instruments were removed from service. CONCLUSIONS: This large outbreak of P. aeruginosa infections related to bronchoscopy was apparently caused by a loose biopsy-port cap in the bronchoscopes. Instrument safety and surveillance methods for bronchoscopy must be improved, and better recall procedures are needed for medical devices.

Academic Medical Centers↗

PubMed2003

A 17-month evaluation of a chlorine dioxide water treatment system to control Legionella species in a hospital water supply.

OBJECTIVE: To assess the safety and efficacy of a chlorine dioxide water treatment system in controlling Legionella in a hospital water supply. DESIGN: For 17 months following installation of the system, we performed regular water cultures throughout the building, assessed chlorine dioxide and chlorite levels, and monitored metal corrosion. RESULTS: Sites that grew Legionella species decreased from 41% at baseline to 4% (P = .001). L. anisa was the only species recovered and it was found in samples of both hot and cold water. Levels of chlorine dioxide and chlorite were below Environmental Protection Agency (EPA) limits for these chemicals in potable water. Further, enhanced carbon filtration effectively removed the chemicals, even at chlorine dioxide levels of more than twice what was used to treat the water. After 9 months, corrosion of copper test strips exposed to the chlorine dioxide was not higher than that of control strips. During the evaluation period, there were no cases of nosocomial Legionella in the building with the system, whereas there was one case in another building. CONCLUSIONS: Our results indicate that operation of a chlorine dioxide system effectively removed Legionella species from a hospital water supply. Furthermore, we found that the system was safe, as levels of chlorine dioxide and chlorite were below EPA limits. The system did not appear to cause increased corrosion of copper pipes. Our results indicate that chlorine dioxide may hold promise as a solution to the problem of Legionella contamination of hospital water supplies.

Academic Medical Centers↗

PubMed2002

Enteral fluconazole is well absorbed in critically ill surgical patients.

BACKGROUND: Enteral fluconazole, a triazole antifungal agent with an excellent oral bioavailability, has not been widely studied in critically ill surgical patients. METHODS: During a randomized placebo-controlled trial of enteral fluconazole (N = 130) versus placebo (N = 130) for the prevention of fungal infections in critically ill surgical patients, trough fluconazole levels were measured after the loading dose and 3 times weekly during intensive care unit stay. Minimum inhibitory concentrations (MICs) for fluconazole were measured on all infecting Candida isolates. RESULTS: Four hundred sixty-seven serum samples were assayed for fluconazole levels in 121 patients. The most common infecting fungal species was Candida albicans, isolated in 14 of 31 infections (45%). Other infecting species were C glabrata, C tropicalis, and C parapsilosis. Mean fluconazole levels were above the highest MIC for C albicans and C parapsilosis in all but 5 patients (4%). Mean fluconazole levels were below the median MIC for C glabrata in 93 of 121 patients (77%). No significant relationship was seen between fluconazole levels and risk for fungal infection. CONCLUSIONS: Serum fluconazole levels are above the MIC of most yeast species found in these patients. These levels may not be above the MIC of C glabrata, the second most common Candida isolate causing infection in this study.

Absorption↗

PubMed2002

A prospective study to determine whether cover gowns in addition to gloves decrease nosocomial transmission of vancomycin-resistant enterococci in an intensive care unit.

BACKGROUND: Vancomycin-resistant enterococci (VRE) remain a significant nosocomial pathogen. Current guidelines of the Hospital Infection Control Practices Advisory Committee (HICPAC) of the Centers for Disease Control and Prevention (CDC) recommend the use of gowns and gloves for some interactions with VRE-infected or -colonized patients to prevent nosocomial transmission of VRE. OBJECTIVE: To assess the effect of disposable cover gowns on preventing nosocomial transmission of VRE. DESIGN AND SETTING: Prospective study in a 16-bed medical intensive care unit of a university teaching hospital. PATIENTS: All patients who were at risk to acquire VRE, were admitted to the intensive care unit from August 1998 to January 1999, and had at least two perirectal cultures were included in the analysis of VRE acquisition. INTERVENTION: VRE isolation precautions were changed from gowns and gloves to gloves alone. MAIN OUTCOME risk factors for VRE acquisition. RESULTS: The VRE acquisition rate was 1.80 cases per 100 days at risk in the gown and gloves period compared with 3.78 in the gloves only period (P = .04). In a proportional hazards model adjusted for length of stay, gloves only precautions with a hazard ratio of 2.5 (P = .02; 95% confidence interval, 1.2 to 5.3) were the only independent risk factor for VRE acquisition. CONCLUSION: Our data lend support to current HICPAC recommendations for the use of cover gowns to decrease nosocomial transmission of VRE.

Baltimore↗

PubMed2002

The ability of hospital ventilation systems to filter Aspergillus and other fungi following a building implosion.

OBJECTIVES: To assess the ability of hospital air handling systems to filter Aspergillus, 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. Aspergillus counts 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 to Aspergillus, 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 in Aspergillus, other fungi, and particles generated by the implosion. Aspergillus measurements were paralleled by particle counts.

Air Conditioning↗