Enzyme-linked immunosorbent assay for serodiagnosis of Helicobacter pylori in dyspeptic patients and volunteer blood donors.

Helicobacter pylori, an important etiological agent in the development of gastritis, peptic ulcer and gastric carcinoma, can be detected by the enzyme-linked immunosorbent assay (ELISA). Our objectives were: (1) to evaluate the efficacy of a commercial ELISA kit (Pyloriset EIA-G III) in sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for diagnosis of H. pylori infection in Thai dyspeptic patients in Khon Kaen Thailand; and (2) to examine the seroprevalence of H. pylori among blood donors at Srinagarind Hospital's Blood Bank, Khon Kaen University, by the commercial ELISA. Gastric biopsies obtained from 137 dyspeptic patients were diagnosed by culture, rapid urease test (RUT) and histology. Serum samples from the same dyspeptic patients and 100 healthy blood donors were assayed using the commercial ELISA. H. pylori infection in dyspeptic patients was considered positive when the culture or both RUT and histology were positive. Using a cut-off value at a titer of 20 U/ml (as recommended by the manufacturer), we found the commercial ELISA kit had a sensitivity of 93.3%, specificity of 75.3%, PPV of 74.7%, NPV of 93.5% and accuracy of 83.2%. The overall H. pylori seroprevalence in the healthy blood donors was 57%. Of the 100 healthy blood donors, 39 (60.9%) of the males and 18 (50.0%) of the females were seropositive.

Salmonellosis and the food chain in Khon Kaen, northeastern Thailand.

Non-typhoidal salmonellosis is a major cause of food-borne illness in Thailand. Specific serotyping of Salmonellae, linked with certain foods, can be used to identify outbreaks, transmission, and for surveillance. We aimed to identify the chain of non-typhoidal Salmonella transmission from food to humans in five slums, two open markets, four supermarkets and an abattoir in the municipality of Khon Kaen. During three months representing the cool-dry, hot-dry, and rainy seasons of 2002, culture samples were collected from water, food, pork, and chicken. Stool cultures of food venders, and others in the same area, were performed. Serological typing was done by the WHO National Salmonella and Shigella Center in Thailand. Of the food, drinking water, and stool samples from food handlers and healthy persons, 18, 7, 11, and 5%, respectively, were positive for Salmonella. Nearly all (96-98%) of the fresh pork and chicken, both from the open markets and supermarkets, were positive for Salmonella. The major Salmonella serovars were S. Anatum, S. Rissen, S. Virchow, S. Enteritidis and S. Panama, similar throughout the food chain and to the other reports that year. To reduce the incidence of human salmonellosis, several preventative measures must be taken where animals are produced, slaughtered and processed, and at home and in eateries. Vulnerable groups, such as infants, the elderly and the immuno-compromised, should be made aware of their increased susceptibility to food-borne disease.