Detection of campylobacter in gastroenteritis: comparison of direct PCR assay of faecal samples with selective culture. (1/2074)

The prevalence of campylobacter gastroenteritis has been estimated by bacterial isolation using selective culture. However, there is evidence that certain species and strains are not recovered on selective agars. We have therefore compared direct PCR assays of faecal samples with campylobacter culture, and explored the potential of PCR for simultaneous detection and identification to the species level. Two hundred unselected faecal samples from cases of acute gastroenteritis were cultured on modified charcoal cefoperazone deoxycholate agar and subjected to DNA extraction and PCR assay. Culture on CCDA indicated that 16 of the 200 samples contained 'Campylobacter spp.'. By contrast, PCR assays detected campylobacters in 19 of the 200 samples, including 15 of the culture-positive samples, and further identified them as: C. jejuni (16), C. coli (2) and C. hyointestinalis (1). These results show that PCR offers a different perspective on the incidence and identity of campylobacters in human gastroenteritis.  (+info)

An outbreak of viral gastroenteritis associated with consumption of sandwiches: implications for the control of transmission by food handlers. (2/2074)

Although food handlers are often implicated as the source of infection in outbreaks of food-borne viral gastroenteritis, little is known about the timing of infectivity in relation to illness. We investigated a gastroenteritis outbreak among employees of a manufacturing company and found an association (RR = 14.1, 95% CI = 2.0-97.3) between disease and eating sandwiches prepared by 6 food handlers, 1 of whom reported gastroenteritis which had subsided 4 days earlier. Norwalk-like viruses were detected by electron microscopy or reverse transcriptase-polymerase chain reaction (RT-PCR) in stool specimens from several company employees, the sick food handler whose specimen was obtained 10 days after resolution of illness, and an asymptomatic food handler. All RT-PCR product sequences were identical, suggesting a common source of infection. These data support observations from recent volunteer studies that current recommendations to exclude food handlers from work for 48-72 h after recovery from illness may not always prevent transmission of Norwalk-like viruses because virus can be shed up to 10 days after illness or while exhibiting no symptoms.  (+info)

Helicobacter pylori vacuolating toxin forms anion-selective channels in planar lipid bilayers: possible implications for the mechanism of cellular vacuolation. (3/2074)

The Helicobacter pylori VacA toxin plays a major role in the gastric pathologies associated with this bacterium. When added to cultured cells, VacA induces vacuolation, an effect potentiated by preexposure of the toxin to low pH. Its mechanism of action is unknown. We report here that VacA forms anion-selective, voltage-dependent pores in artificial membranes. Channel formation was greatly potentiated by acidic conditions or by pretreatment of VacA at low pH. No requirement for particular lipid(s) was identified. Selectivity studies showed that anion selectivity was maintained over the pH range 4.8-12, with the following permeability sequence: Cl- approximately HCO3- > pyruvate > gluconate > K+ approximately Li+ approximately Ba2+ > NH4+. Membrane permeabilization was due to the incorporation of channels with a voltage-dependent conductance in the 10-30 pS range (2 M KCl), displaying a voltage-independent high open probability. Deletion of the NH2 terminus domain (p37) or chemical modification of VacA by diethylpyrocarbonate inhibited both channel activity and vacuolation of HeLa cells without affecting toxin internalization by the cells. Collectively, these observations strongly suggest that VacA channel formation is needed to induce cellular vacuolation, possibly by inducing an osmotic imbalance of intracellular acidic compartments.  (+info)

Campylobacter jejuni--an emerging foodborne pathogen. (4/2074)

Campylobacter jejuni is the most commonly reported bacterial cause of foodborne infection in the United States. Adding to the human and economic costs are chronic sequelae associated with C. jejuni infection--Guillian-Barre syndrome and reactive arthritis. In addition, an increasing proportion of human infections caused by C. jejuni are resistant to antimicrobial therapy. Mishandling of raw poultry and consumption of undercooked poultry are the major risk factors for human campylobacteriosis. Efforts to prevent human illness are needed throughout each link in the food chain.  (+info)

Adenovirus infection after pediatric bone marrow transplantation. (5/2074)

Retrospective analysis of 206 patients undergoing 215 consecutive bone marrow transplants (BMT) at St Jude Children's Research Hospital between November 1990 and December 1994 identified 6% (seven male, six female) with adenovirus infection. The affected patients had a median age of 7.9 years (range 3-24 years) at time of transplantation. Although transplants were performed for hematologic malignancies, solid tumors or nonmalignant conditions, only patients with hematologic malignancies had adenoviral infections. Adenovirus was first detected at a median of 54 days (range -4 to +333) after BMT. Adenovirus developed in eight of 69 (11.6%) patients receiving grafts from matched unrelated or mismatched related donors, in four of 52 (7.7%) receiving grafts from HLA-matched siblings, and in one of 93 (1.1%) receiving autografts. The most common manifestation of adenovirus infection was hemorrhagic cystitis, followed by gastroenteritis, pneumonitis and liver failure. The incidence of adenovirus infection in pediatric BMT patients at our institution is similar to that reported in adult patients. Using univariate analysis, use of total body irradiation and type of bone marrow graft were significant risk factors for adenovirus infection. Only use of total body irradiation remained as a factor on multiple logistic regression analysis.  (+info)

Presence of Campylobacter and Salmonella in sand from bathing beaches. (6/2074)

The purpose of this study was to determine the presence of thermophilic Campylobacter spp. and Salmonella spp. in sand from non-EEC standard and EEC standard designated beaches in different locations in the UK and to assess if potentially pathogenic strains were present. Campylobacter spp. were detected in 82/182 (45%) of sand samples and Salmonella spp. in 10/182 (6%). Campylobacter spp. were isolated from 46/92 (50%) of samples from non-EEC standard beaches and 36/90 (40%) from EEC standard beaches. The prevalence of Campylobacter spp. was greater in wet sand from both types of beaches but, surprisingly, more than 30% of samples from dry sand also contained these organisms. The major pathogenic species C. jejuni and C. coli were more prevalent in sand from non-EEC standard beaches. In contrast, C. lari and urease positive thermophilic campylobacters, which are associated with seagulls and other migratory birds, were more prevalent in sand from EEC standard beaches. Campylobacter isolates were further characterized by biotyping and serotyping, which confirmed that strains known to be of types associated with human infections were frequently found in sand on bathing beaches.  (+info)

A community outbreak of food-borne small round-structured virus gastroenteritis caused by a contaminated water supply. (7/2074)

In August 1994, 30 of 135 (23%) bakery plant employees and over 100 people from South Wales and Bristol in the United Kingdom, were affected by an outbreak of gastroenteritis. Epidemiological studies of employees and three community clusters found illness in employees to be associated with drinking cold water at the bakery (relative risk 3.3, 95%, CI 1.6-7.0), and in community cases with eating custard slices (relative risk 19.8, 95%, CI 2.9-135.1) from a variety of stores supplied by one particular bakery. Small round-structured viruses (SRSV) were identified in stool specimens from 4 employees and 7 community cases. Analysis of the polymerase and capsid regions of the SRSV genome by reverse transcription-polymerase chain reaction (RT-PCR) demonstrated viruses of both genogroups (1 and 2) each with several different nucleotide sequences. The heterogeneity of the viruses identified in the outbreak suggests that dried custard mix may have been inadvertently reconstituted with contaminated water. The incident shows how secondary food contamination can cause wide-scale community gastroenteritis outbreaks, and demonstrates the ability of molecular techniques to support classical epidemiological methods in outbreak investigations.  (+info)

Characterization of intestinal disease associated with human immunodeficiency virus infection and response to antiretroviral therapy. (8/2074)

Combination antiretroviral therapies suppress human immunodeficiency virus (HIV) in peripheral blood, but the effect in gastrointestinal mucosa is uncertain. The occurrence of pathogen-negative diarrhea led to speculation that local HIV infection is etiologic. Mucosal cellular reservoirs for HIV were documented by use of several techniques. Correlations were found among gastrointestinal symptoms, histopathologic findings, cytokine expression, lymphoid apoptosis, and HIV RNA and protein expression in rectal mucosa. Disproportionate depletion of mucosal CD4+ lymphocytes also was found. The short-term effects of antiretroviral therapies were examined to test the hypothesis that these changes are directly related to mucosal HIV infection. Therapy was associated with decreased symptoms, with comparable drops in peripheral blood and mucosal HIV RNA contents, and by increases in blood and mucosal CD4+ lymphocyte contents. In addition, the number of apoptotic cells also declined during therapy. These results suggest that HIV plays a direct role in producing intestinal dysfunction.  (+info)

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