Nation-wide prospective surveillance of Clostridium difficile infections in hospitals in Belgium, July 2007-June 2008.

We report here baseline data from the first year of compulsory surveillance of Clostridium difficile infections (CDI) in hospitals in Belgium. Between 1 July 2007 and 30 June 2008, 2,704 CDI were reported: 12% were recurrent and 66% were hospital-associated (half of which occurred 15 days or more after admission). CDI was considered the cause of death (direct or indirect) for 10% of the episodes. The median incidence of CDI was 1.5 per 1,000 admissions and 1.9 per 10,000 hospital-days for all cases, and 0.9 per 1,000 admissions, and 1.1 per 10,000 hospital-days for hospital-associated cases. Further investigation of risk stratification by average length of stay in the reporting hospitals is warranted as a way to improve the comparability of indicators across hospitals and surveillance systems. In spite of methodological issues, the surveillance of CDI in Belgian hospitals has been able to produce robust baseline data that should allow monitoring of trends at hospital and national level, and provide a basis for international comparisons. Remaining challenges are to define and monitor targets for the control of CDI, and to improve the individual feed-back of data at hospital level.

Hospitals in Europe Link for Infection Control through Surveillance (HELICS). Inter-country comparison of rates of surgical site infection--opportunities and limitations.

Many countries in Europe have created national systems for the surveillance of healthcare associated infections (HCAI). The Hospitals in Europe Link for Infection Control through Surveillance (HELICS) has provided a standardised approach to surveillance of HCAI and formed a 'network of networks' to enable data from hospitals contributing to national networks also to be submitted to the HELICS database. This paper describes the set of surgical site infection surveillance data collected in 2004. It includes 111,361 operations in six categories of surgical procedure from 14 countries. The analysis demonstrates that incidence density provides a better measure for comparison than cumulative incidence as it takes some account of difference in length of post-operative stay and post-discharge surveillance. Comparisons should also take account of differences in mix of procedures, variation in risk factors and sensitivity of case finding. This rich dataset provides a unique opportunity to explore variation in rates of SSI and improve understanding of factors that impact on inter-country comparisons.

Cetirizine inhibits bradykinin-induced cutaneous wheal and flare in atopic and healthy subjects.

BACKGROUND: Kinins are vasoactive mediators involved in allergic reactions. When applied on the skin or in the nose, bradykinin (BK) elicits inflammation that is poorly affected by previous H1-blockade. The aim of this study was to compare the possible effect of cetirizine (an H1-antagonist) on wheal and flare responses to BK, histamine, and compound 48/80 in atopic and healthy subjects. METHODS: In a randomized, double-blind, crossover study, eight atopic and eight healthy subjects received cetirizine (10 mg/day) or placebo for 3 days before cutaneous tests. Intradermal tests (IDT) and prick tests (PT) were performed with BK (20 nmol/ml for IDT and 20 micromol/ml for PT), histamine (100 microg/ml IDT and 100 mg/ml PT), and compound 48/80 (100 microg/ml IDT and 100 mg/ml PT) as positive controls and saline as negative control. The skin responses were monitored by measurement of wheal and flare areas. RESULTS: BK, histamine, and 48/80 induced wheal and flare reactions in all placebo-treated subjects. Histamine elicited larger wheal and flare reactions than BK and 48/80. IDT with BK induced four- to six-fold larger wheal and flare reaction than PT. No differences in BK-induced wheal and flare were observed between atopic and healthy subjects. In atopic subjects, cetirizine induced a significant reduction of flare reactions after the BK test (80% for IDT, and 94% for PT [P<0.01]). Moreover, cetirizine reduced significantly BK-induced wheals by 70% for IDT (P<0.01) and 65% for PT (P<0.01). A similar inhibiting effect of cetirizine was also observed in healthy subjects. CONCLUSIONS: These findings showed that the wheal and flare reactions induced by BK challenge were markedly inhibited by previous intake of cetirizine. The mechanism by which this effect is mediated cannot be established at present.

Cetirizine and loratadine: a comparison using the ED50 in skin reactions.

To quantify objectively the comparative potencies of the antihistamines, loratadine and cetirizine, we determined the dose that inhibits histamine-induced skin reactions by 50% of the maximum response (ED50) for each drug. Cetirizine at 2.5, 5 or 10 mg, loratadine at 10, 20 or 40 mg or placebo were given to 14 healthy female subjects in a randomized double-blind crossover design. Inhibition of the wheal and flare response to the histamine prick test (10, 100 and 500 mg/ml) was evaluated. Depending on the histamine concentrations, the ED50s for wheals were in the ranges 4.3 - 4.7, 2.1 - 2.2 and 1.7 - 1.9 mg cetirizine, 2, 4 and 6 h after dosing, respectively. For loratadine, the ED50 for wheals were in the ranges 35.6 - > 40, 9.1 - 24.1 and 9.1 - 13.9 mg, 2, 4 and 6 h after dosing, respectively. Calculation of the ED50 demonstrated that, on average, cetirizine is seven to nine times more potent than loratadine at inhibiting wheal and flare reactions.

Cetirizine inhibits bradykinin-induced cutaneous wheal and flare in atopic and healthy subjects.

BACKGROUND: Kinins are vasoactive mediators involved in allergic reactions. When applied on the skin or in the nose, bradykinin (BK) elicits inflammation that is poorly affected by previous H1-blockade. The aim of this study was to compare the possible effect of cetirizine (an H1-antagonist) on wheal and flare responses to BK, histamine, and compound 48/80 in atopic and healthy subjects. METHODS: In a randomized, double-blind, crossover study, eight atopic and eight healthy subjects received cetirizine (10 mg/day) or placebo for 3 days before cutaneous tests. Intradermal tests (IDT) and prick tests (PT) were performed with BK (20 nmol/ml for IDT and 20 micromol/ml for PT), histamine (100 microg/ml IDT and 100 mg/ml PT), and compound 48/80 (100 microg/ml IDT and 100 mg/ml PT) as positive controls and saline as negative control. The skin responses were monitored by measurement of wheal and flare areas. RESULTS: BK, histamine, and 48/80 induced wheal and flare reactions in all placebo-treated subjects. Histamine elicited larger wheal and flare reactions than BK and 48/80. IDT with BK induced four- to sixfold larger wheal and flare reaction than PT. No differences in BK-induced wheal and flare were observed between atopic and healthy subjects. In atopic subjects, cetirizine induced a significant reduction of flare reactions after the BK test (80% for IDT, and 94% for PT [P < 0.01]). Moreover, cetirizine reduced significantly BK-induced wheals by 70% for IDT (P < 0.01) and 65% for PT (P < 0.01). A similar inhibiting effect of cetirizine was also observed in healthy subjects. CONCLUSIONS: These findings showed that the wheal and flare reactions induced by BK challenge were markedly inhibited by previous intake of cetirizine. The mechanism by which this effect is mediated cannot be established at present.

Role of antigen-induced cytokine release in atopic pruritus.

In order to further evaluate the role of cytokines in the induction of atopic pruritus, leukocytes from 10 atopic eczema patients or 10 nonallergic controls were stimulated in vitro with mite or birch pollen antigen for 1 and 4 days. Subjects were prick-tested with the supernatants, and whealing and itching were evaluated 20 and 60 min later. The supernatants were also examined for the contents of GM-CSF, IL-2, IL-6 and IL-8 by ELISA and TNFalpha. Two hours prior to testing, the antihistamine cetirizine (20 mg) or a placebo tablet were given to the patients according to a randomized, double-blind study protocol. After pricking with antigen-stimulated leukocyte supernatants, 6 of 10 patients but no controls reacted mostly at 20 min with whealing and/or pruritus. In the cetirizine-treated group, no decrease in these skin reactions was seen compared to placebo. Analysis for cytokines showed increased levels of IL-8 in allergen-stimulated samples, with no correlation to the induction of itching or whealing by these supernatants. IL-6 levels were low and variable, and GM-CSF, IL-2 and TNFalpha levels were always below standard values. These data show that leukocytes selectively release IL-8 in response to in vitro antigen stimulation. They furthermore provide additional support for the concept that as yet to be identified products play a role in atopic pruritus.

[Skin reactions to bradykinin]. / La réactivité cutanée à la bradykinine.

A large series of experiments carried out in animals and humans suggest that histamine release is not involved in the leakage phenomenon induced by bradykinin (BK) challenge. These experiments comprise in vitro studies on skin and bronchial human mast cells and in vivo studies on guinea pig airways and human skin using mepyramine, chlorpheniramine and terfenadine as reference H1-anti-histamines. Nevertheless, it has been shown recently that the H1 antagonist cetirizine 10 mg p.o. markedly inhibits skin reactions induced by BK challenge (intradermal injection of 212 micrograms BK in 10 microL saline and prick test with a solution of 21.2 micrograms/microL). In a guinea pig model, this drug also inhibited the bronchospasm induced by increasing concentrations of BK given by iv route (0.25 to 2 micrograms/Kg) and aerosol (3 to 300 micrograms/Kg). This inhibition was similar to the one obtained with the specific BK antagonist HOE 140 (15 pM/Kg). New data in the literature suggest the existence of various pharmacological mediators possibly involved in the BK-induced reaction: neuromediators, nitric oxyde and PAF. They also suggest that this reaction presents itself as a well defined sequence of pharmacological events. Since we could show that there is no binding of cetirizine to a human recombinant B2 receptor in vitro, some hypotheses are raised in order to explain this unexpected inhibiting effect of cetirizine.

Effects of monohydroxylated fatty acids on arterial smooth muscle cell properties.

The hydroxylated derivatives of polyunsaturated fatty acids may be potent modulators of basic biological responses involved in pathological processes, including atherosclerosis. The object of the present investigation was to study the effects of monohydroxylated fatty acids (namely 12-HETE) on the properties of aortic smooth muscle cells (SMC) in culture. The changes in cell expression of differentiation antigen alpha-SM actin and 2P1A2 was followed by computerized morphometry, using specific monoclonal antibodies and the activation of cells by measuring cell motility. In addition, intracellular [Ca2+]i mobilization and IP3 formation were studied. Finally, the metabolic routes of monohydroxylated compounds and their effects on PGI2 secretion were reported. The results demonstrate that 12-HETE is able to stimulate the phenotypic modulation. PGI2 production and motility of arterial SMCs, despite any detectable activity in increasing [Ca2+]i or IP3 formation. By contrast with parent compounds 15-HETE and 13-HODE, which appear as potent prodifferentiating molecules, 12-HETE is specifically metabolized via a 10-11 reductase pathway in addition to the classical beta-oxidation pathway. Taken together, our results suggest that cellular metabolism of 12-HETE, produced by platelets in the vicinity of the arterial intima, and also by cells present inside the atherosclerotic intima, or associated with modified LDL may play a key role in the atherosclerotic process.

In vitro platelets/endothelial cells interactions in presence of acetylsalicylic acid at various dosages.

Venous endothelium is able to release in vitro substances which modifies platelet aggregation. A vascular fragment incubated in Michaelis buffer (pH 7.30), aliquoted and tested on platelet-rich-plasma partially inhibits the aggregometry parameters. Addition of acetylsalicylic acid (ASA) at ultra low dose (0.1 nM final solution in the incubation tube) presents a reversed effect on this inhibition. To explain this phenomenon, 6-keto-PGF1 alpha and von Willebrand factor were dosed in the incubation media. After determination of an active level of 6-keto-PGF1 alpha (200 pg/100 microliters), 2 series were made: series 1 included the values below 200 pg/100 microliters incubation media, series 2, the values above 200 pg/100 microliters incubation media. When the vascular fragment was incubated as described above, the results of aggregometry ratio for series 1 were: test A (without ASA): 0.84 +/- 0.18, test B1 (with 0.1 nM of ASA): 0.87 +/- 0.13. For series 2, they became: test A: 0.75 +/- 0.27, test B1: 0.93 +/- 0.16. Control was always: 1.00 +/- 0.00. For the same groups, 6-keto-PGF1 alpha values were: for series 1, test A: 81 +/- 57, test B1: 81 +/- 60 pg/100 microliters incubation medium, for series 2, test A: 596 +/- 495, test B1: 383 +/- 263 pg/100 microliters incubation medium. Analyses were also performed with 2 high doses of ASA (B2: 10(5) nM and B3: 10(6) nM final solution) in the same experimental conditions. In these groups, aggregation parameters were decreased (0.86 +/- 0.14 for 10(5) nM, 0.84 +/- 0.15 for 10(6) nM) as well as 6-keto-PGF1 alpha production (189 +/- 199 for 10(5) nM, 152 +/- 182 for 10(6) nM). For these two last ASA treatments, comparison of the results in groups set up according to the sensitive 6-keto-PGF1 alpha value (200 pg/100 microliters solution) showed no modification. So it seems that a certain reactive state, specific of ultra low dose treatment is necessary for the vascular endothelium to be sensitive at such treatment.

Pharmacological modulation of 86Rb efflux from aortic endothelial cells.

The ATP-induced efflux of 86Rb from prelabelled bovine aortic endothelial cells was inhibited by quinine (50 microM) but not by a tetraethylammonium (5 mM) or apamin (50 nM). Neither sulfonylureas nor pinacidil had a significant effect on the rate of 86Rb efflux from the endothelial cells. These data are consistent with the presence of intermediate conductance Ca2(+)-activated K+ channels in endothelial cells. ATP-dependent K+ channels, sensitive to sulfonylureas and pinacidil, could not be detected.

Effects of changes in extra- and intracellular K+ on the endothelial production of prostacyclin.

1. Changes in the KCl concentration of the incubation medium, from 0 to 80 mM, had no effect on the basal or ATP-stimulated release of prostacyclin (PGI2) from bovine aortic endothelial cells. 2. The monovalent cation ionophores, valinomycin and nigericin (5 microM), enhanced the release of PGI2 from endothelial cells stimulated by ATP or bradykinin. 3. The action of nigericin, unlike that of valinomycin, was time-dependent, abolished in a high-KCl medium and associated with an increased efflux of 86Rb and a time-dependent depletion of intracellular K+. 4. Ouabain (1-100 microM) also enhanced the release of PGI2 in response to ATP and induced a significant depletion of intracellular K+ in bovine aortic endothelial cells. 5. In conclusion, modifications of the endothelial cell membrane potential, resulting from changes in the extracellular K+ concentration, do not modulate the basal or ATP-stimulated production of PGI2. An acute depletion of intracellular K+ by nigericin or ouabain enhances the production of PGI2 in aortic endothelial cells stimulated by ATP or bradykinin.

Palmitoyl-L-carnitine increases the release of prostacyclin from vascular endothelial cells.

Prostacyclin biosynthesis is dramatically increased in patients with acute myocardial infarction. As palmitoylcarnitine accumulates during myocardial ischemia, the action of this metabolite on the endothelial production of prostacyclin was studied. Palmitoyl-L-carnitine (10-100 microM) enhanced the release of prostacyclin and free arachidonic acid from bovine aortic endothelial cells. This action was mimicked by lysophosphatidylcholine, but by none of the following compounds: acetylcarnitine, carnitine, palmitic acid, sphingosine, dihydrosphingosine and N-stearoyl-dihydrosphingosine. In addition to mobilizing free arachidonate, palmitoylcarnitine induced the release of free choline and phosphorylcholine presumably via the activation of phospholipases C and D. Palmitoyl-L-carnitine had also a cytotoxic effect on the endothelial cells. These data suggest that the increased biosynthesis of prostacyclin in myocardial infarction might be partially explained by the accumulation and release of palmitoyl-L-carnitine.

Enhanced release of prostacyclin from quin 2-loaded endothelial cells.

The acetoxymethyl ester (AM) of quin-2 (quin-2/AM) enhanced the release of prostacyclin (PGI2) from bovine aortic endothelial cells stimulated by ATP, bradykinin or ionophore A23187. It also increased the mobilization of free arachidonic acid in response to ATP. Ca2+-clamping with a combination of EGTA and quin-2/AM abolished the response to ATP. The effect of quin-2/AM was mimicked by a structural analog, the acetoxymethyl ester of 1,2-bis(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA/AM), but not by the heavy metal chelator, tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) and only slightly by fura-2/AM. The mechanism of this pharmacological action of quin-2/AM and its potential for the design of PGI2-stimulating drugs remain to be explored.