Ganglioside GM1 mimicry in Campylobacter strains from sporadic infections in the United States.
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To determine whether GM1-like epitopes in Campylobacter species are specific to O serotypes associated with Guillain-Barre syndrome (GBS) or whether they are frequent among random Campylobacter isolates causing enteritis, 275 random enteritis-associated isolates of Campylobacter jejuni were analyzed. To determine whether GM1-like epitopes in Campylobacter species are specific to O serotypes associated with Guillan-Barre syndrome (GBS) or whether they are frequent among random Campylobacter isolates causing enteritis, 275 enteritis-associated isolates, randomly collected in the United States, were analyzed using a cholera-toxin binding assay [corrected]. Overall, 26.2% of the isolates were positive for the GM1-like epitope. Of the 36 different O serotypes in the sample, 21 (58.3%) contained no strains positive for GM1, whereas in 6 serotypes (16.7%), >50% of isolates were positive for GM1. GBS-associated serotypes were more likely to contain strains positive for GM1 than were non-GBS-associated serotypes (37.8% vs. 15.1%, P=.0116). The results suggest that humans are frequently exposed to strains exhibiting GM1-like mimicry and, while certain serotypes may be more likely to possess GM1-like epitopes, the presence of GM1-like epitopes on Campylobacter strains does not itself trigger GBS. (+info)
A reassessment of the cost-effectiveness of water and sanitation interventions in programmes for controlling childhood diarrhoea.
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Cost-effectiveness analysis indicates that some water supply and sanitation (WSS) interventions are highly cost-effective for the control of diarrhoea among under-5-year-olds, on a par with oral rehydration therapy. These are relatively inexpensive "software-related" interventions such as hygiene education, social marketing of good hygiene practices, regulation of drinking-water, and monitoring of water quality. Such interventions are needed to ensure that the potentially positive health impacts of WSS infrastructure are fully realized in practice. The perception that WSS programmes are not a cost-effective use of health sector resources has arisen from three factors: an assumption that all WSS interventions involve construction of physical infrastructure, a misperception of the health sector's role in WSS programmes, and a misunderstanding of the scope of cost-effectiveness analysis. WSS infrastructure ("hardware") is generally built and operated by public works agencies and financed by construction grants, operational subsidies, user fees and property taxes. Health sector agencies should provide "software" such as project design, hygiene education, and water quality regulation. Cost-effectiveness analysis should measure the incremental health impacts attributable to health sector investments, using the actual call on health sector resources as the measure of cost. The cost-effectiveness of a set of hardware and software combinations is estimated, using US$ per case averted, US$ per death averted, and US$ per disability-adjusted life year (DALY) saved. (+info)
Interactions between enteropathogenic Escherichia coli and epithelial cells.
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Enteropathogenic Escherichia coli (EPEC) may be considered a paradigm for a multistage interaction between pathogen and host cell. EPEC strains produce a type IV pilus that is associated with initial adherence to host cells, and these strains possess a type III secretion apparatus that is necessary for transducing signals to host cells. Secretion of three Esp proteins is required for activation of a phosphotyrosine-containing receptor that allows EPEC to bind intimately to host cells via the bacterial outer membrane protein intimin. Intimately attached bacteria rest upon a pedestal composed of host cytoskeletal proteins in an arrangement recognized as the attaching and effacing phenotype. The precise molecular interactions that lead to these dramatic alterations in the host cell cytoskeleton remain to be elucidated. (+info)
Evaluation designs for adequacy, plausibility and probability of public health programme performance and impact.
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The question of why to evaluate a programme is seldom discussed in the literature. The present paper argues that the answer to this question is essential for choosing an appropriate evaluation design. The discussion is centered on summative evaluations of large-scale programme effectiveness, drawing upon examples from the fields of health and nutrition but the findings may be applicable to other subject areas. The main objective of an evaluation is to influence decisions. How complex and precise the evaluation must be depends on who the decision maker is and on what types of decisions will be taken as a consequence of the findings. Different decision makers demand not only different types of information but also vary in their requirements of how informative and precise the findings must be. Both complex and simple evaluations, however, should be equally rigorous in relating the design to the decisions. Based on the types of decisions that may be taken, a framework is proposed for deciding upon appropriate evaluation designs. Its first axis concerns the indicators of interest, whether these refer to provision or utilization of services, coverage or impact measures. The second axis refers to the type of inference to be made, whether this is a statement of adequacy, plausibility or probability. In addition to the above framework, other factors affect the choice of an evaluation design, including the efficacy of the intervention, the field of knowledge, timing and costs. Regarding the latter, decision makers should be made aware that evaluation costs increase rapidly with complexity so that often a compromise must be reached. Examples are given of how to use the two classification axes, as well as these additional factors, for helping decision makers and evaluators translate the need for evaluation--the why--into the appropriate design--the how. (+info)
At our hospital, the number of cases of Clostridium difficile-associated diarrhoea increased from 29 in 1993 to 210 in 1995. The case notes of 110 patients with C difficile-associated diarrhoea during the first 6 months of 1995 were analysed retrospectively. The majority of the patients (106) had received antibiotics before the onset of diarrhoea; 46 had received three or more different antibiotics and 28 had received metronidazole. In 19 patients, the first stool sample after the onset of diarrhoea was negative for C difficile cytotoxin, with a mean delay of 8.2 days before a positive stool sample. We conclude that C difficile-associated diarrhoea was associated with the usage of multiple antibiotics, and that metronidazole did not protect against colonisation by C difficile. We also recommend that more than one stool sample should be tested for the C difficile cytotoxin. (+info)
Dietary advice for acute diarrhoea in general practice: a pilot study.
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BACKGROUND: Although there is no evidence that diet shortens acute diarrhoea, doctors tend to give dietary advice. AIM: To test the effects of eating and drinking normally on the duration of acute diarrhoea and on the feeling of well-being. METHOD: Randomized single-blinded, controlled trial in urban and semi-urbanized areas. Patients aged 3-70 years suffering with diarrhoea at least three times on the preceding day, lasting no more than five days, were eligible. Two regimes were randomly allocated to practices. In the intervention group, the advice was to eat everything one liked and to drink more. The control group was advised to follow a strict regime of fasting for 24 hours and was subsequently given specified limitations. RESULTS: No significant differences between the 44 patients in the intervention group and the 27 in the control group were found for the duration of watery diarrhoea (median 14 versus 13 hours), or the total number of evacuations (2 versus 2.5). Among the items concerning well-being, only nausea (51% versus 23%) showed a significant difference. CONCLUSION: In this pilot study, the null hypothesis that both treatments will show equal results cannot be confirmed or rejected because of the small number of participants. Despite our efforts, we included fewer patients than expected. This might be due to the data-forms, which were rather complicated and voluminous for both, including doctors and participants. (+info)
Cellular microbiology: can we learn cell physiology from microorganisms?
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Cellular microbiology is a new discipline that is emerging at the interface between cell biology and microbiology. The application of molecular techniques to the study of bacterial pathogenesis has made possible discoveries that are changing the way scientists view the bacterium-host interaction. Today, research on the molecular basis of the pathogenesis of infective diarrheal diseases of necessity transcends established boundaries between cell biology, bacteriology, intestinal pathophysiology, and immunology. The use of microbial pathogens to address questions in cell physiology is just now yielding promising applications and striking results. (+info)
Observations on the use of tetracycline and niacinamide as antipruritic agents in atopic dogs.
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Tetracycline and niacinamide were administered in combination to 19 atopic dogs to determine their effectiveness in controlling pruritus. The pruritus was controlled successfully in only one dog. One dog experienced diarrhea that was severe enough to warrant stopping the medication. (+info)