Abstract

In 1992, in collaboration with the Dutch Institute for Investigation of Primary Health Care (NIVEL) and the National Institute of Public Health and Environmental Protection (RIVM), a national sentinel study of incidence and cause of gastro-enteritis was started. Patients with complaints of gastro-enteritis, consulting participating practitioners, were asked to complete a questionnaire and send a faecal sample to the nearest laboratory for examination. 24 laboratories took part in the study. Samples were investigated for the presence of Salmonella, Shigella and Campylobacter. For adequate interpretation of the results, an investigation of quality assurance in the different laboratories was carried out. The RIVM distributed artificially contaminated, simulated faecal samples. The laboratories were asked to examine these samples, according to their usual methods, for the presence of Salmonella, Shigella and Campylobacter. One laboratory didn't investigate the received samples. The other laboratories were able to demonstrate the presence of Salmonella, Shigella and Campylobacter in samples contaminated with these bacteria. None of the laboratories isolated bacteria from the control sample. Escherichia coli, added to a sample as interfering strain, was suppressed or discriminated by the selective or distinguishing characteristics of the methods used.