English 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.
