Thermodynamic temperature assignment to the point of inflection of the melting curve of high-temperature fixed points.

The thermodynamic temperature of the point of inflection of the melting transition of Re-C, Pt-C and Co-C eutectics has been determined to be 2747.84 ± 0.35 K, 2011.43 ± 0.18 K and 1597.39 ± 0.13 K, respectively, and the thermodynamic temperature of the freezing transition of Cu has been determined to be 1357.80 ± 0.08 K, where the ± symbol represents 95% coverage. These results are the best consensus estimates obtained from measurements made using various spectroradiometric primary thermometry techniques by nine different national metrology institutes. The good agreement between the institutes suggests that spectroradiometric thermometry techniques are sufficiently mature (at least in those institutes) to allow the direct realization of thermodynamic temperature above 1234 K (rather than the use of a temperature scale) and that metal-carbon eutectics can be used as high-temperature fixed points for thermodynamic temperature dissemination. The results directly support the developing mise en pratique for the definition of the kelvin to include direct measurement of thermodynamic temperature.

Ross River virus disease in two Dutch travellers returning from Australia, February to April 2015.

We report two cases of Ross River virus (RRV) infection in Dutch travellers who visited Australia during February to April 2015. These cases coincided with the largest recorded outbreak of RRV disease in Australia since 1996. This report serves to create awareness among physicians to consider travel-related RRV disease in differential diagnosis of patients with fever, arthralgia and/or rash returning from the South Pacific area, and to promote awareness among professionals advising travellers to this region.

Evaluation of three enzyme immunoassays and a loop-mediated isothermal amplification test for the laboratory diagnosis of Clostridium difficile infection.

The laboratory diagnosis of Clostridium difficile infection (CDI) consists of the detection of toxigenic Clostridium difficile, and/or its toxins A or B in stool preferably in a two-step algorithm. In a prospective study, we compared the performance of three toxin enzyme immunoassays (EIAs)-ImmunoCard Toxins A & B, Premier Toxins A & B and C. diff Quik Chek Complete, which combines a toxins test and a glutamate dehydrogenase (GDH) antigen EIA in one device -and the loop-mediated isothermal amplification assay Illumigene C. difficile. In total 986 stool samples were analyzed. Compared with toxigenic culture as the gold standard, sensitivities, specificities, PPV and NPV values of the toxin EIAs were 41.1-54.8 %, 98.9-100 %, 75.0-100 % and 95.5-96.5 % respectively, of the Illumigene assay 93.3 %, 99.7 %, 95.8 % and 99.5 %. Illumigene assays performed significantly better for non-014/020 PCR-ribotypes than for C. difficile isolates belonging to 014/020. Discrepant analysis of three culture-negative, but Illumigene-positive samples, revealed the presence of toxin genes using real-time PCRs. In addition to the GDH EIA (NPV of 99.8 %), the performance of Illumigene allows this test to be introduced as a first screening test for CDI- or as a confirmation test for GDH -positive samples, although the initial invalid Illumigene result of 4.4 % is a point of concern.

Spatial clustering and livestock exposure as risk factor for community-acquired Clostridium difficile infection.

OBJECTIVES: Clostridium difficile infections (CDI) account for 1.5% of diarrhoeic episodes in patients attending a general practitioner in the Netherlands, but its sources are unknown. We searched for community clusters to recognize localized point sources of CDI. METHODS: Between October 2010 and February 2012, a community-based prospective nested case-control study was performed in three laboratories in the Netherlands with a study population of 2 810 830 people. Bernoulli spatial scan and space-time permutation models were used to detect spatial and/or temporal clusters of CDI. In addition, a multivariate conditional logistic regression model was constructed to test livestock exposure as a supposed risk factor in CDI patients without hospital admission within the previous 12 weeks (community-acquired (CA) CDI). RESULTS: In laboratories A, B and C, 1.3%, 1.8% and 2.1% of patients with diarrhoea tested positive for CDI, respectively. The mean age of CA-CDI patients (n = 124) was 49 years (standard deviation, 22.6); 64.5% were female. No spatial or temporal clusters of CDI cases were detected compared to C. difficile-negative diarrhoeic controls. Except for one false-positive signal, no spatiotemporal interaction amongst CDI cases was found. Livestock exposure was not related to CA-CDI (odds ratio, 0.99; 95% confidence interval, 0.44-2.24). Ten percent of CA-CDIs was caused by PCR ribotype 078, spatially dispersed throughout the study area. CONCLUSIONS: The absence of clusters of CDI cases in a community cohort of diarrhoeic patients suggests a lack of localized point sources of CDI in the living environment of these patients.

Bacterium-induced autoimmune reactivity.

Evidence is growing that autoimmune reactivity results from a combination of endogenous (e.g. MHC type) and environmental factors. Our experimental study focuses on the induction of autoimmune reactivity by microbial factors. Splenic formation and serum levels of anti-erythrocyte antibodies and circulating immune complexes were taken as parameters. It was found that experimental infection of mice with Escherichia coli and Salmonella typhimurium was accompanied by clear signs of autoimmune reactivity, smooth bacteria being almost ten times as potent as rough mutant strains. An attempt was made to correlate the data obtained with live bacteria to their corresponding endotoxins. It was concluded that the induction of more prominent autoimmune reactivity by smooth bacteria must be ascribed to a longer survival time in vivo. Our data support the view that bacterium-derived factors are involved in the etiology (and possibly also the course) of autoimmune diseases.

Schistosomiasis haematobium as a cause of vulvar hypertrophy.

Schistosomiasis is the most frequently imported helminthic infection in The Netherlands. Patients with Schistosoma haematobium infections usually present with fever, hematuria, dysuria, or urinary frequency. The ectopic localizations in female genital schistosomiasis are frequently misdiagnosed or confounded with sexually transmitted diseases or genital tract cancers. This paper describes a patient who presented with vulvar hypertrophy as a symptom of acute female genital schistosomiasis. The aim of this paper is to draw attention to a neglected parasitic disease that in the future will be encountered in increasing numbers in Western Europe.

[Systemic fat necrosis and septic arthritis in acute pancreatitis]. / Systemische vetnecrose en septische artritis bij acute pancreatitis.

Systemic fatty necrosis secondary to acute pancreatitis was diagnosed in a 47-year-old man with high fever and painful nodules on the arms and the upper legs. This was complicated by fatal septic shock, septic arthritis and extensive soft tissue infections with Enterobacter cloacae, which was unsuccessfully treated with several antibiotic regimens, and from which the patient died.

Diarrhoea in general practice: when should a Clostridium difficile infection be considered? Results of a nested case-control study.

Clostridium difficile infections (CDIs) are frequent in hospitals, but also seem to increase in the community. Here, we aim to determine the incidence of CDI in general practice and to evaluate current testing algorithms for CDI. Three Dutch laboratories tested all unformed faeces (12,714) for C. difficile when diagnostic testing (for any enteric pathogen) was requested by a general practitioner (GP). Additionally, a nested case-control study was initiated, including 152 CDI patients and 304 age and sex-matched controls. Patients were compared using weighted multivariable logistic regression. One hundred and ninety-four samples (1.5%) were positive for C. difficile (incidence 0.67/10,000 patient years). This incidence was comparable to that of Salmonella spp. Compared with diarrhoeal controls, CDI was associated with more severe complaints, underlying diseases, antibiotic use and prior hospitalization. In our study, GPs requested a test for C. difficile in 7% of the stool samples, thereby detecting 40% of all CDIs. Dutch national recommendations advise testing for C. difficile when prior antibiotic use or hospitalization is present (18% of samples). If these recommendations were followed, 61% of all CDIs would have been detected. In conclusion, C. difficile is relatively frequent in general practice. Currently, testing for C. difficile is rare and only 40% of CDI in general practice is detected. Following recommendations that are based on traditional risk factors for CDI, would improve detection of CDI.

Clinical and microbiological characteristics of community-onset Clostridium difficile infection in The Netherlands.

To elucidate the prevalence, characteristics and risk factors of community-onset Clostridium difficile infection (CO-CDI), an uncontrolled prospective study was performed. For 3 months in 2007-2008, three laboratories in The Netherlands tested all unformed stool samples submitted by general practitioners (GPs) for C. difficile by enzyme immunoassay for toxins A and B, irrespective of whether GPs specifically requested this. Patients with positive results were asked to complete a questionnaire. Positive stool samples were cultured for C. difficile, and isolates were characterized. In all, 2443 stool samples from 2423 patients were tested, and 37 patients (1.5%) with positive toxin test results were identified. Mixed infections were not found. Age varied from 1 to 92 years, and 18% were under the age of 20 years. Diarrhoea was typically frequent and watery, sometimes with admixture of blood or fever. Eight of 28 patients (29%) suffered recurrences. Among 31 patients with toxin-positive stool samples for whom information was available, 20 (65%) had not been admitted to a healthcare institution in the year before, 13 (42%) had not used antibiotics during the 6 months before, and eight (26%) had neither risk factor. A separate analysis for patients whose samples were both toxin-positive and culture-positive produced similar results. Cultured C. difficile isolates belonged to 13 different PCR ribotypes, and 24% of the isolates were non-typeable (rare or new) PCR ribotypes. In conclusion, CO-CDI can affect all age groups, and many patients do not have known risk factors. Several PCR ribotypes not encountered in hospital-associated outbreaks were found, suggesting the absence of a direct link between outbreaks and community-onset cases.

Lack of effect of shorter turnaround time of microbiological procedures on clinical outcomes: a randomised controlled trial among hospitalised patients in the Netherlands.

Shortening the turnaround time of microbiological procedures was associated with an improved clinical outcome in two studies performed in the USA. To study the clinical impact of a shortened turnaround time in a northwest European setting in which an automated system was used for bacterial identification and susceptibility testing, a single-blind, prospective, randomised controlled trial was conducted in a hospital in the Netherlands. All hospitalised patients with a bacterial infection confirmed by culture were randomly assigned to a control (conventional) group or an intervention (rapid) group. Overnight methods were used for identification and susceptibility testing in the control group, while the Vitek 2 system (bioMerieux, Marcy l'Etoile, France) was used in the rapid group. In each of three consecutive study periods, accelerating factors were added progressively to the laboratory workflow of the rapid group to increase same-day reporting, whereas methods remained identical in the conventional group. The turnaround time of the microbiological cycle using the Vitek 2 system as compared to conventional methods was studied and the clinical impact of a shortened turnaround time assessed in terms of mortality, morbidity, and cost. For the rapid groups, the turnaround time was significantly shorter for oral reporting of final susceptibility results in all three study periods and for reporting on paper in the third study period. There was no significant difference between groups in any of the clinical impact variables. Vitek 2 results were available for reporting significantly earlier as compared to conventional testing. For the overall patient group in our hospital setting, however, this had no clinical impact.

Induction of auto-antibody formation in C3H/HeJ mice by cobra venom factor.

Recently, we demonstrated that lipopolysaccharide (LPS)-hyporesponsive C3H/HeJ mice show a very high background number of splenic antibody-forming cells with specificity for bromelain-treated isologous erythrocytes. This background level was not or only slightly enhanced by LPS injection. In this paper it is reported that the existing response of C3H/HeJ mice is about doubled by treatment of the animals with cobra venom factor (CVF). This increase is very similar to the LPS-induced potentiation of the auto-antibody response of C3H/Tif and other LPS-responder mice. The absence of auto-antibodies in the sera of CVF-treated C3H/HeJ mice, however, points at a different mechanism of B cell activation. The mediation of the CVF-induced stimulation of the B cells of C3H/HeJ mice by covalent C3-glycoprotein complexes and the need for an additional stimulus is discussed.

Endotoxin-induced auto-immunity in mice. III. Comparison of different endotoxin preparations.

Six different endotoxin preparations derived from Escherichia coli and Salmonella typhimurium subspecies were compared as to their potencies to provoke auto-immune phenomena in mice. The numbers of spleen cells forming antibodies to bromelain-treated isologous erythrocytes or anti-DNA antibodies, the serum levels of these auto-antibodies, and the circulating immune complex titres were determined. As far as comparison on a weight base was concerned, S. typhimurium Re-mutant lipopolysaccharide appeared to be the most active preparation in inducing auto-antibody formation. Upon comparison of amounts with equal activity in the limulus amoebocyte lysate assay, however, S. typhimurium lipid A turned out to be the most potent. The contribution of O-type specific polysaccharides, phosphate groups, and the lipid A moiety to the potencies of the endotoxin preparations is discussed.

Endotoxin-induced auto-immunity in mice. I. Time and dose dependence of production and serum levels of antibodies against bromelain-treated mouse erythrocytes and circulating immune complexes.

Injection of mice with endotoxin results in the formation of auto-antibodies and the appearance of soluble immune complexes in the blood. In this study the relationship between the production and serum levels of autohaemolysins and circulating immune complex titres was investigated. Immune complexes were detected by a solid-phase C1q-binding assay and found to contain antibodies of the IgM, but not of the IgG class. Individual mice showed marked differences as to their splenic plaque-forming cells, serum autohaemolysin, and circulating immune complex responses, both in kinetic studies and dose-response experiments. The dissociation between production and serum levels of auto-antibodies was ascribed to extrasplenic synthesis or a disproportionate production per plasma cell. The independent behaviour of the circulating immune complex response could, at least partially, be attributed to differential complement-dependent clearance from the circulation. The implications of our findings for the laboratory diagnosis of auto-immunity at the blood level are being discussed.

Endotoxin-induced auto-immunity in mice. II. Reactivity of LPS-hyporesponsive and C5-deficient animals.

Auto-antibody responses and circulating immune complex levels of mice with abnormal reactions to endotoxin were investigated after injection with the bacterial product. It was observed that C3H/HeJ mice displayed very high background plaque-forming cell responses towards bromelain-treated isologous erythrocytes which were slightly enhanced by endotoxin treatment. The same animals, however, did not bear autohaemolysins in their serum, but became so upon endotoxin injection. A possible relationship between the high background reactivity of C3H/HeJ mice and the low toxicity of endotoxin in these animals is discussed. Neither untreated nor lipopolysaccharide-injected C3H/HeJ mice showed significant immune complex levels in their sera. This may be explained by their hyporesponsiveness, but by a low sensitivity to the toxic effects of endotoxin as well. C5-deficient and C5-sufficient mice showed similar auto-immune reactions, indicating that C5a, which is responsible for other effects of endotoxin, is not involved in endotoxin-induced auto-immunity.

Short-term follow-up by serology of patients given antibiotic treatment for Helicobacter pylori infection.

Helicobacter pylori serology and in particular enzyme-linked immunosorbent assays for the measurement of immunoglobulin G (IgG) antibody titers form an accurate means of diagnosing H. pylori infection in patients before treatment. H. pylori serology is of limited value in monitoring treatment because of the slow decline in antibody titers. In the present study we aimed to measure the most suitable moment after antibiotic treatment at which serology should be used to monitor treatment. Sixty-four patients who had nonulcer dyspepsia and H. pylori infection and who underwent upper gastrointestinal endoscopy because of persistent dyspeptic symptoms were included in the study. H. pylori cure was confirmed by histology and culture 5 weeks after the completion of the antibiotic treatment. Serological examination was performed before therapy and at 5 weeks, 10 weeks, and 1 year after the completion of antibiotic treatment. Diagnostic performance was assessed by receiver-operating characteristic analysis. The areas under the receiver-operating characteristic curves of the H. pylori antibody titers at 5 weeks, 10 weeks, and 1 year after the completion of treatment were 0.53 (95% confidence interval [CI], 0.36 to 0.69), 0.60 (95% CI, 0.43 to 0.76), and 0.78 (95% CI, 0.63 to 0.93), respectively. The areas under the receiver-operating characteristic curves of the changes in H. pylori IgG antibody titers at 5 weeks, 10 weeks, and 1 year after the completion of treatment in comparison with the pretreatment titers were 0.85 (95% CI, 0.72 to 0.97), 0.96 (95% CI, 0.89 to 1.0), and 1.0 (95% CI, not estimable), respectively. We conclude that serology forms a useful means of monitoring treatment in patients with nonulcer dyspepsia and H. pylori infection as early as 10 weeks and maybe even sooner after the completion of treatment for the infection.