Is the combination of UV-C light and bleach less effective than bleach alone for intensive care unit surface disinfection?

Background: Chlorine-based disinfectants, such as bleach, are commonly used for cleaning in healthcare settings to prevent the transmission of nosocomial pathogens. To enhance the efficacy of disinfection, ultraviolet-C (UV-C) light systems have been proposed to supplement standard cleaning procedures. As bleach decomposes in UV light, we hypothesised that the use of UV-C light as an adjunct to manual cleaning with bleach, may decrease the efficacy of disinfection instead. Methods: In the laboratory, stainless steel sheets and plastic keyboards were inoculated with Pseudomonas aeruginosa (∼106 CFU/ml) and subjected to treatment with either UV-C light only, bleach only or a combination of UV-C light and bleach. The residual bioburden (CFU/ml) was quantified through conventional microbiological techniques. Results were compared to non-exposed control surfaces and against each treatment strategy. Results: On tested surfaces, there were statistically significant reductions in P. aeruginosa when surfaces were treated with UV-C light only (>2.5 log10 reduction), bleach only (>5.6 log10 reduction) and a combination of UV-C light and bleach (>6.3 log10 reduction) compared to positive control (P < 0.001, all treatment strategies). No significant differences were observed when surfaces were treated with the addition of UV-C light to bleach compared to treatment with bleach alone. Conclusion: There was no difference in the efficacy of disinfection against P. aeruginosa with the combined treatment strategy of UV-C light and bleach compared to bleach alone under laboratory conditions. Further studies are warranted to elucidate the effectiveness of this technology on other healthcare-associated pathogens.

High-Sensitivity Cardiac Troponin for Risk Assessment in Patients With Chronic Coronary Artery Disease.

BACKGROUND: Cardiac troponin is used for risk stratification of patients with acute coronary syndromes; however, the role of testing in other settings remains unclear. OBJECTIVES: The aim of this study was to evaluate whether cardiac troponin testing could enhance risk stratification in patients with chronic coronary artery disease independent of disease severity and conventional risk measures. METHODS: In a prospective cohort of consecutive patients with symptoms suggestive of stable angina attending for outpatient coronary angiography, high-sensitivity cardiac troponin I was measured before angiography, and clinicians were blinded to the results. The primary outcome was myocardial infarction or cardiovascular death during follow-up. RESULTS: In 4,240 patients (age 66 years [IQR: 59-73 years], 33% female), coronary artery disease was identified in 3,888 (92%) who had 255 (6%) primary outcome events during a median follow-up of 2.4 years (IQR: 1.3-3.6 years). In patients with coronary artery disease, troponin concentrations were 2-fold higher in those with an event compared with those without (6.7 ng/L [IQR: 3.2-14.2 ng/L] vs 3.3 ng/L [IQR: 1.7-6.6 ng/L]; P < 0.001). Troponin concentrations were associated with the primary outcome after adjusting for cardiovascular risk factors and coronary artery disease severity (adjusted HR: 2.3; 95% CI: 1.7-3.0, log10 troponin; P < 0.001). A troponin concentration >10 ng/L identified patients with a 50% increase in the risk of myocardial infarction or cardiovascular death. CONCLUSIONS: In patients with chronic coronary artery disease, cardiac troponin predicts risk of myocardial infarction or cardiovascular death independent of cardiovascular risk factors and disease severity. Further studies are required to evaluate whether routine testing could inform the selection of high-risk patients for treatment intensification. (Myocardial Injury in Patients Referred for Coronary Angiography [MICA]; ISRCTN15620297).