Persistence of nosocomial bacteria on 2 biocidal fabrics based on silver under conditions of high relative humidity.

BACKGROUND: The survival of pathogenic microorganism on fabrics in the health care environment has a important role in nosocomial infections. The use of biocidal fabrics and surfaces could reduce the prevalence of the microorganisms in the hospital environment. METHODS: In this study, the persistence of nosocomial bacteria on 2 fabrics containing biocidal fibers (BF) in the long term following desiccation and subsequent storage was examined at 40% and 90% relative humidity (RH). RESULTS: Very few strains survived more than 7 days at 40% RH on fabrics containing 67% BF, and only strains of Acinetobacter baumanii and Pseudomonas aeruginosa survived on fabric containing 100% BF. None of the strains tested survived 14 days on the 2 fabrics, 67% or 100% BF, under these environmental conditions. In contrast, at higher RH (∼90%), most of the strains tested showed prolonged survival on both fabrics, and all strains of Klebsiella pneumoniae, Enterobacter aerogenes, and A baumannii survived for more than 14 days; however, in a Petri dish, most of the microorganisms tested showed a higher survival even at 28 days. The gram-positive cocci and A baumannii were the most persistent bacteria on the Petri dish. CONCLUSIONS: This study emphasizes the effect of RH on the survival of nosocomial bacteria on 2 commercially available fabrics containing biocide. Evidence of the clinical efficacy of these BF-containing fabrics is lacking.

Extravirgin olive oil consumption reduces risk of atrial fibrillation: the PREDIMED (Prevención con Dieta Mediterránea) trial.

BACKGROUND: The PREDIMED (Prevención con Dieta Mediterránea) randomized primary prevention trial showed that a Mediterranean diet enriched with either extravirgin olive oil or mixed nuts reduces the incidence of stroke, myocardial infarction, and cardiovascular mortality. We assessed the effect of these diets on the incidence of atrial fibrillation in the PREDIMED trial. METHODS AND RESULTS: Participants were randomly assigned to 1 of 3 diets: Mediterranean diet supplemented with extravirgin olive oil, Mediterranean diet supplemented with mixed nuts, or advice to follow a low-fat diet (control group). Incident atrial fibrillation was adjudicated during follow-up by an events committee blinded to dietary group allocation. Among 6705 participants without prevalent atrial fibrillation at randomization, we observed 72 new cases of atrial fibrillation in the Mediterranean diet with extravirgin olive oil group, 82 in the Mediterranean diet with mixed nuts group, and 92 in the control group after median follow-up of 4.7 years. The Mediterranean diet with extravirgin olive oil significantly reduced the risk of atrial fibrillation (hazard ratio, 0.62; 95% confidence interval, 0.45-0.85 compared with the control group). No effect was found for the Mediterranean diet with nuts (hazard ratio, 0.89; 95% confidence interval, 0.65-1.20). CONCLUSIONS: In the absence of proven interventions for the primary prevention of atrial fibrillation, this post hoc analysis of the PREDIMED trial suggests that extravirgin olive oil in the context of a Mediterranean dietary pattern may reduce the risk of atrial fibrillation. CLINICAL TRIAL REGISTRATION URL: http://www.controlled-trials.com. Unique identifier: ISRCTN35739639.

A Mediterranean diet rich in virgin olive oil may reverse the effects of the -174G/C IL6 gene variant on 3-year body weight change.

Only a few studies have analyzed the effects of the potential interaction between the -174G/C polymorphism of IL6 gene and the adherence to the Mediterranean diet (MD) on adiposity indexes. Our aim was to investigate the interplay between the -174G/C polymorphism of the IL6 gene and a Mediterranean-style diet on body weight changes after 3 years of nutritional intervention in a high cardiovascular risk population. A total of 737 participants, aged 55-80 years were assigned to a low-fat diet or to a Mediterranean-style diet group with high intake of virgin olive oil (VOO) or nuts. Anthropometric measurements were taken at baseline and after 3-year follow-up. The -174G/C polymorphism of the IL6 gene was genotyped. Minor allele frequency (C) was 0.39. At baseline, the CC genotype was associated with higher measures of adiposity. After 3 years, a significant interaction (p=0.028) was found between the polymorphism (GG+GC versus CC) and the nutritional intervention: CC subjects following the MD+VOO had the lowest body weight gain. In conclusion, at baseline, CC subjects for the -174G/C polymorphism of IL6 had the highest body weight and BMI. However, after 3 years of nutritional intervention with MD+VOO, these subjects were predicted to have the greatest reduction in body weight.

Alcohol consumption is associated with high concentrations of urinary hydroxytyrosol.

BACKGROUND: Previously, we reported the presence of hydroxytyrosol in red wine and higher human urinary recovery of total hydroxytyrosol than that expected after a single red wine intake. We hypothesized that the alcohol present in wine could promote endogenous hydroxytyrosol generation. OBJECTIVE: The objective was to assess the relation between alcohol consumption and urinary hydroxytyrosol concentrations. DESIGN: This was a cross-sectional study with baseline data from a subsample of the PREvención con DIeta MEDiterránea (PREDIMED) trial, an intervention study directed at testing the efficacy of the Mediterranean diet on the primary prevention of cardiovascular disease. Participants included 1045 subjects, aged 55-80 y, who were at high cardiovascular risk. Alcohol consumption was estimated through a validated food-frequency questionnaire. Urinary hydroxytyrosol and ethyl glucuronide, a biomarker of alcohol consumption, were measured. RESULTS: Urinary ethyl glucuronide concentrations were directly related to alcohol and wine consumption (P < 0.001) as well as to urinary hydroxytyrosol in both sexes (P < 0.001). The degree of alcohol consumption was directly associated with urinary hydroxytyrosol in male alcohol consumers (P < 0.001). Multivariate logistic regression analyses showed a significant linear trend (P < 0.05) for elevated hydroxytyrosol concentrations with an increase in alcohol consumption. Intakes of >20 g (2 drinks)/d and >10 g (1 drink)/d alcohol in men and women, respectively, were associated (P < 0.05) with elevated concentrations of hydroxytyrosol. CONCLUSIONS: We report for the first time a direct association between urinary hydroxytyrosol and alcohol consumption at a population level. These findings reinforce previous work in human and animal models that examines wine as a source of hydroxytyrosol and alcohol as an indirect promoter of endogenous hydroxytyrosol generation. This trial was registered at controlled-trials.com/isrctn/ as ISRCTN 35739639.

Fluorescent assay based on resazurin for detection of activity of disinfectants against bacterial biofilm.

A new, quick method, using the resazurin dye test as a bacterial respiration indicator, has been developed to assay the antibacterial activity of various substances used as disinfectants against bacterial biofilm growth on clinical devices. Resazurin was used to measure the presence of active biofilm bacteria, after adding disinfectant, in relation to a standard curve generated from inocula in suspension of the same organism used to grow the biofilm. The biofilm was quantified indirectly by measuring the fluorescent, water-soluble resorufin product produced when resazurin is reduced by reactions associated with respiration. Four products used as disinfectants and the biofilm growth of five bacterial species on carriers made of materials commonly found in clinical devices were studied. Under test conditions, chlorhexidine, NaOCl, ethanol, and Perasafe at concentrations of 0.2, 0.01, 350, and 0.16 mg/ml, respectively, all produced 5-log reductions in biofilm cell numbers on the three different carriers. The redox-driven test depends on bacterial catabolism, for which reason resazurin reduction produces an analytic signal of the bacterial activity in whole cells, and therefore could be used for determining disinfectant efficacy in an assay based on the metabolic activity of microorganisms grown as biofilm or in suspension.

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A fluorescent method for assessing the antimicrobial efficacy of disinfectant against Escherichia coli ATCC 35218 biofilm.

In this study, a versatile method was developed to assess biocide efficacy against Escherichia coli biofilm growth on carriers made of five different materials. The glucuronidase activity of live E. coli on a fluorogenic substrate (4-methylumbellyferyl-beta-D-glucuronide, MUG) was used as a viability test. Fluorescence emissions from cellular suspensions of E. coli in the test range displayed a linear response with a MUG concentration of 10 microg ml(-1). A glucuronidase activity curve with cellular suspensions of E. coli calculated as colony-forming units per milliliter showed a good correlation (0.9487 and 0.917 for 1 and 18 h of incubation, respectively), with counts obtained from biofilm containing this organism; E. coli cultures in suspension were used as standard. Three agents commonly used as disinfectants, sodium hypochlorite, hydrogen peroxide, and ethanol, were tested at use concentrations and at one-half and decimal dilutions. At decimal dilutions, ethanol at 70% proved to be the least active disinfectant on E. coli biofilm. Unlike other methods, our method permits the testing of disinfectant efficacy against biofilm growth on different materials. In preliminary assays, glass, polyvinyl chloride, polypropylene, polycarbonate, and silicon were tested. Because they gave the lowest E. coli counts after 24 and 48 h, glass and polypropylene were the two materials to which biofilm adhered least strongly.

Heavy metal concentrations in the general population of Andalusia, South of Spain: a comparison with the population within the area of influence of Aznalcóllar mine spill (SW Spain).

Levels of metalloids (As - urine) and heavy metals (Hg - urine, Cd - whole blood and Zn - serum) were determined by atomic absorption spectrometry in 601 subjects living in the area affected by the Aznalcóllar mine spill (SW, Spain) and compared with those of a representative sample (960 subjects) selected from the Andalusian community (non-affected area), southern Spain. The characteristic parameters of the analytical method including uncertainty were determined for each metal. Potential associations of metal concentration with age, sex and body mass index as well as life-style habits (smoking, alcohol consumption and food habits) were explored. Concentrations of all the metals studied were statistically higher in the population of the affected area with respect to that of the non-affected area in Andalusia, although levels were always lower or similar to the values reported for the general population and below occupational reference limits. In conclusion, there is a lack of evidence that the spill had any incidence on human health in the population living in the affected area. There are few references in scientific literature reporting values from large series of samples, and hence our data could be useful for further studies.

Toenail cerium levels and risk of a first acute myocardial infarction: the EURAMIC and heavy metals study.

The association between cerium status and risk of first acute myocardial infarction (AMI) was examined in a case-control study in 10 centres from Europe and Israel. Cerium in toenails was assessed by neutron activation analysis in 684 cases and 724 controls aged 70 years or younger. Mean concentrations of cerium were 186 and 173 microg/kg in cases and controls, respectively. Cerium was positively associated with low socio-economic status, smoking, mercury, zinc and scandium (p0.001). Cases had significantly higher levels of cerium than controls after adjustment for age and centre (case-control ratio 1.074; 95% CI 1.002-1.151) and increased in further adjustment for other cardiovascular risk factors 1.085; 95% CI 1.025-1.149. The risk after adjustment for age and centre was higher with increasing cerium levels (p for trend=0.02). After adjustment for BMI, history of hypertension, smoking, alcohol intake, diabetes, family history of CHD, beta-carotene, lycopene, alpha-tocopherol, selenium, mercury and scandium, the OR for the highest quintile was 1.43 (95% CI 0.85-2.41; p-trend 0.08). When we applied this same model in non-smokers the odds ratios in the 4th and 5th quintiles of cerium as compared with the lowest were 2.09 (95% CI 1.05-4.16) and 2.81 (95% CI 1.21-6.52), respectively, p-trend 0.011. Our results suggest that toenail cerium levels may be associated with an increased risk of AMI, but more research is warranted to shed further light and fully understand the plausibility and public health implications of these findings.

A fluorescence bioassay to detect residual formaldehyde from clinical materials sterilized with low-temperature steam and formaldehyde.

A microtiter plate toxicity test based on fluorescence was developed to determine the residual concentration of formaldehyde on medical items after LTSF sterilization. The residual formaldehyde on eight common materials, some of which are used in different clinical instruments and devices were analysed after sterilization with LTSF. Formaldehyde residues were detected on cotton, filter paper, natural rubber, PVC, and silicone-coated latex, but not on polyurethane, silicone or glass. Formaldehyde never exceeded the recommended maximum concentration on clinical devices of about 5 microg/cm2. The results were compared with those obtained by means of a chemical method, the correlation being good (R2=0.9396). The biological method proposed here is fast and can be automated, which means that it could be used as a screening method when there are doubts as to the accumulation of residues on clinical materials or instruments that are going to be sterilized with LTSF.

Influence of organic solvents on the sensitivity of a bioluminescence toxicity test with Vibrio harveyi.

The possibility of using organic solvents (OSs) to increase the susceptibility of bioluminescent microorganisms in a bioassay for assessing the toxicity of chemicals dissolved in water was investigated. To conduct the tests acetonitrile, dimethyl sulfoxide, ethanol, methanol, and isopropanol were used as OSs and Cd, Hg, and Zn as reference toxicants. The addition of OSs modified the toxicity of the three metals to Vibrio harveyi, according on the bioluminescence assay used. The sensitivity of the luminescence bioassay for Hg increased in the presence of the five OSs, thus indicating a greater toxic effect. However, the sensitivity of the assay for the other two metals, Cd and Zn, increased or decreased (lesser toxic effect) depending on the concentration at which the OSs were used. No correlation was observed between the concentration of the five OSs and the toxicity of the three reference toxicants. From this it can be deduced that none of these OSs could be recommended for increasing generically the sensitivity of toxicity biotests using V. harveyi.

Correlation of two bioluminescence and one fluorogenic bioassay for the detection of toxic chemicals.

The linear correlation between the EC50 values of 50 substances obtained in luminescence bioassays using Vibrio fischeri and Vibrio harveyi and in a fluorogenic bioassay using Escherichia coli was investigated. As a result, a significant correlation was found between the said values in all three toxicity tests. The bioassay using V. harveyi had a sensitivity similar to that of the fluorogenic bioassay, and the bioassay using V. fischeri was the least sensitive of all. The sensitivity of the three bioassays for each of the tested substances, chiefly heavy metals, organic solvents, orgnochlorated compounds, and pesticides, differed in the majority of the cases. The three bioassays were quantified using the same laboratory apparatus and the data were processed in the same way. The possibility of designing a battery of toxicity tests that can be performed using the same apparatus but different organisms and parameters is discussed.

Association between toenail scandium levels and risk of acute myocardial infarction in European men: the EURAMIC and Heavy Metals Study.

The association between scandium status and risk of acute myocardial infarction (MI) was examined in a multicentre case control study in 10 centres from Europe and Israel. Scandium in toenails was assessed in 684 cases and 724 controls less than 70 years of age. Mean concentrations of toenail scandium were 6.74 micro/kg in cases and 7.75 microg/kg in controls. Scandium among controls, adjusted for age and centre was positively associated with concentrations of lycopene and oleic acid in adipose tissue (P = 0.002 for both nutrients). Pearson correlations adjusted for age and centre were significant (P < 0.05) between scandium and lycopene (r = 0.08), zinc (r = 0.08), mercury (r = 0.18) and oleic acid (r = 0.21). Overall, cases had lower levels of scandium than controls after adjustment for age and centre (case control ratio, 0.87; 95% CI 0.79-0.96). This association persisted after adjustment for other cardiovascular risk factors (case-control ratio 0.88; 95% CI, 0.79-0.98). The risk of MI at high scandium levels was reduced after adjustment for age and centre (P-trend = 0.04). Further adjustments for BMI, history of hypertension, smoking, alcohol intake, diabetes, family history of CHD, alpha-tocopherol, beta-carotene, lycopene, selenium and mercury slightly attenuated this trend (P = 0.055). Our results suggest that toenail scandium level is associated with a reduced risk of acute MI, but we are uncertain whether this element can really play a protective role in the development of CHD. Without an identified plausible mechanism, these results should be regarded as preliminary and should be tested in future studies.