Hubert H. Attaway

Copper Surfaces Reduce the Rate of Healthcare-Acquired Infections in the Intensive Care Unit

OBJECTIVE. Healthcare-acquired infections (HAIs) cause substantial patient morbidity and mortality. Items in the environment harbor microorganisms that may contribute to HAIs. Reduction in surface bioburden may be an effective strategy to reduce HAIs. The inherent biocidal properties of copper surfaces offer a theoretical advantage to conventional cleaning, as the effect is continuous rather than episodic. We sought to determine whether placement of copper alloy-surfaced objects in an intensive care unit (ICU) reduced the risk of HAI. DESIGN. Intention-to-treat randomized control trial between July 12, 2010, and June 14, 2011. SETTINg. The ICUs of 3 hospitals. PATIENTS. Patients presenting for admission to the ICU. METHODS. Patients were randomly placed in available rooms with or without copper alloy surfaces, and the rates of incident HAI and/or colonization with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) in each type of room were compared. RESULTS. The rate of HAI and/or MRSA or VRE colonization in ICU rooms with copper alloy surfaces was significantly lower than that in standard ICU rooms (0.071 vs 0.123; P = .020). For HAI only, the rate was reduced from 0.081 to 0.034 (P = .013). CONCLUSIONs. Patients cared for in ICU rooms with copper alloy surfaces had a significantly lower rate of incident HAI and/or colonization with MRSA or VRE than did patients treated in standard rooms. Additional studies are needed to determine the clinical effect of copper alloy surfaces in additional patient populations and settings.

Copper Continuously Limits the Concentration of Bacteria Resident on Bed Rails within the Intensive Care Unit

Cleaning is an effective way to lower the bacterial burden (BB) on surfaces and minimize the infection risk to patients. However, BB can quickly return. Copper, when used to surface hospital bed rails, was found to consistently limit surface BB before and after cleaning through its continuous antimicrobial activity.

Intrinsic bacterial burden associated with intensive care unit hospital beds: Effects of disinfection on population recovery and mitigation of potential infection risk

BACKGROUND Commonly touched items are likely reservoirs from which patients, health care workers, and visitors may encounter and transfer microbes. A quantitative assessment was conducted of the risk represented by the intrinsic bacterial burden associated with bed rails in a medical intensive care unit (MICU), and how disinfection might mitigate this risk. METHODS Bacteria present on the rails from 36 patient beds in the MICU were sampled immediately before cleaning and at 0.5, 2.5, 4.5, and 6.5 hours after cleaning. Beds were sanitized with either a bottled disinfectant (BD; CaviCide) or an automated bulk-diluted disinfectant (ABDD; Virex II 256). RESULTS The majority of bacteria recovered from the bed rails in the MICU were staphylococci, but not methicillin-resistant Staphylococcus aureus. Vancomycin-resistant enterococci were recovered from 3 beds. Bottled disinfectant reduced the average bacterial burden on the rails by 99%. However, the burden rebounded to 30% of that found before disinfection by 6.5 hours after disinfection. ABDD reduced the burden by an average of 45%, but levels rebounded within 2.5 hours. The effectiveness of both disinfectants was reflected in median reductions to burden of 98% for BD and 95% for ABDD. CONCLUSIONS Cleaning with hospital-approved disinfectants reduced the intrinsic bacterial burden on bed rail surfaces by up to 99%, although the population, principally staphylococci, rebounded quickly to predisinfection levels.

Tandem biodegradation of BTEX components by two Pseudomonas sp.

A co-culture of two Pseudomonas putida isolates was enriched from sediment on a mixture of benzene, toluene, ethylbenzene, m-xylene, p-xylene, and o-xylene. The co-culture readily degraded each of the compounds present. Benzene, toluene, and ethylbenzene were used as growth substrates by one isolate, while toluene, m-xylene, and p-xylene were used as growth substrates by the other. Neither isolate could grow on o-xylene, but it was removed in the presence of the other compounds presumably by co-metabolism. The findings presented here support other reports in which constructed communities were effectively used to degrade blends of between two and four of the components of BTEX. However, here the co-culture of two P. putida isolates effectively degraded a complete BTEX stream containing all six of the components.

Evaluation of the Antimicrobial Properties of Copper Surfaces in an Outpatient Infectious Disease Practice

Disease Practice Author(s): Seema Rai, Bruce E. Hirsch, Hubert H. Attaway, Richard Nadan, S. Fairey, J. Hardy, G. Miller, Donna Armellino, Wilton R. Moran, Peter Sharpe, Adam Estelle, J. H. Michel, Harold T. Michels, Michael G. Schmidt Reviewed work(s): Source: Infection Control and Hospital Epidemiology, Vol. 33, No. 2 (February 2012), pp. 200201 Published by: The University of Chicago Press on behalf of The Society for Healthcare Epidemiology of America Stable URL: http://www.jstor.org/stable/10.1086/663701 . Accessed: 12/01/2012 12:27

Mitochondrial uncoupling protein-2 deficiency protects steatotic mouse hepatocytes from hypoxia/reoxygenation

Steatotic livers are sensitive to ischemic events and associated ATP depletion. Hepatocellular necrosis following these events may result from mitochondrial uncoupling protein-2 (UCP2) expression. To test this hypothesis, we developed a model of in vitro steatosis using primary hepatocytes from wild-type (WT) and UCP2 knockout (KO) mice and subjected them to hypoxia/reoxygenation (H/R). Using cultured hepatocytes treated with emulsified fatty acids for 24 h, generating a steatotic phenotype (i.e., microvesicular and broad-spectrum fatty acid accumulation), we found that the phenotype of the WT and UCP2 KO were the same; however, cellular viability was increased in the steatotic KO hepatocytes following 4 h of hypoxia and 24 h of reoxygenation; Hepatocellular ATP levels decreased during hypoxia and recovered after reoxygenation in the control and UCP2 KO steatotic hepatocytes but not in the WT steatotic hepatocytes; mitochondrial membrane potential in WT and UCP2 KO steatotic groups was less than control groups but higher than UCP2 KO hepatocytes. Following reoxygenation, lipid peroxidation, as measured by thiobarbituric acid reactive substances, increased in all groups but to a greater extent in the steatotic hepatocytes, regardless of UCP2 expression. These results demonstrate that UCP2 sensitizes steatotic hepatocytes to H/R through mitochondrial depolarization and ATP depletion but not lipid peroxidation.

Patient environment microbial burden reduction: A pilot study comparison of 2 terminal cleaning methods

Effective cleaning of the patient environment has been advocated to reduce the risk for nosocomial infection. This pilot study compared 2 terminal cleaning methods, a traditional method in which a disinfectant was applied with a wetted cloth and an alternative method in which the disinfectant was applied using the PureMist system (PureCart Systems, Green Bay, WI). There was no difference in effectiveness, with a mean relative reduction of microbial burden of 84% for the traditional method versus 88% for the PureMist method.

Antimicrobial copper alloys decreased bacteria on stethoscope surfaces

HighlightsStethoscopes may transmit bacteria among patients and health care workers.Stethoscope surfaces fabricated with antimicrobial copper alloys harbored significantly fewer bacteria.Of the antimicrobial copper alloys surfaces sampled, 66.3% were free of microbes; 22.4% of control surfaces met this mark. Graphical abstractStethoscope surfaces fabricated with AMCu were consistently found to harbor fewer bacteria: the collective mean concentration for all surfaces measured was 11.7 versus 127.1 ACC/cm2 (P < .00001).Absence of bacteria from the AMCu surfaces (66.3%) was significantly higher (P < .00001) than the control surfaces measured (22.4%). Values are associated with stethoscopes from pediatric arm of the trial. ACC, aerobic colony count; Al, aluminum; AMCu, antimicrobial copper alloy; PVC, polyvinyl chloride; SS, stainless steel. Figure. No Caption available. Background: Stethoscopes may serve as vehicles for transmission of bacteria among patients. The aim of this study was to assess the efficacy of antimicrobial copper surfaces to reduce the bacterial concentration associated with stethoscope surfaces. Methods: A structured prospective trial involving 21 health care providers was conducted at a pediatric emergency division (ED) (n = 14) and an adult medical intensive care unit located in tertiary care facilities (n = 7). Four surfaces common to a stethoscope and a facsimile instrument fabricated from U.S. Environmental Protection Agency–registered antimicrobial copper alloys (AMCus) were assessed for total aerobic colony counts (ACCs), methicillin‐resistant Staphylococcus aureus, gram‐negative bacteria, and vancomycin‐resistant enterococci for 90 days. Results: The mean ACCs collectively recovered from all stethoscope surfaces fabricated from the AMCus were found to carry significantly lower concentrations of bacteria (pediatric ED, 11.7 vs 127.1 colony forming units [CFU]/cm2, P < .00001) than their control equivalents. This observation was independent of health care provider or infection control practices. Absence of recovery of bacteria from the AMCu surfaces (66.3%) was significantly higher (P < .00001) than the control surfaces (22.4%). The urethane rim common to the stethoscopes was the most heavily burdened surface; mean concentrations exceeded the health care–associated infection acquisition concentration (5 CFU/cm2) by at least 25×, supporting that the stethoscope warrants consideration in plans mitigating microbial cross‐transmission during patient care. Conclusions: Stethoscope surfaces fabricated with AMCus were consistently found to harbor fewer bacteria.

Experimental tests of copper components in ventilation systems for microbial control

Colonization of HVAC systems by microbes may lead to release of hazardous bioaerosols containing allergens, irritants, odorants, or infectious agents to indoor air, possibly adversely affecting system performance. Unlike the many common materials used in HVAC systems, copper and copper alloys have been shown in laboratory investigations to kill bacteria and fungi on contact after several hours. This study tested coppers antimicrobial properties in comparison with aluminum in full-scale, carefully controlled air-conditioning systems, four with copper heat exchanger assemblies and four with aluminum assemblies, at identical airflow rates, temperatures, humidity, and input microbe levels. Fungal and bacterial loads on copper surfaces in heat exchangers were lower than on aluminum surfaces by factors of 3500 and more than 500, respectively, over a 4-month period. No statistically significant difference in the release of airborne microbes was detected between copper and aluminum heat exchangers. The moderate conditions employed in this study, while still within the range commonly found in HVAC systems, possibly prevented the high microbial loading on aluminum heat exchanger surfaces from translating into significant differences in airborne concentrations between copper and aluminum systems.