Experimental techniques in the determination of aetiology of acute infantile gastroenteritis.

Techniques used in the research laboratory for the microbiological diagnosis of infantile gastroenteritis are described. These techniques are in essence experimental models of the three pathogenetic mechanisms of bacterial diarrhoea. From the clinical bacteriological standpoint, although there is little difficulty with the identification of enteropathic bacteria such as Salmonella and Shigella, the differentiation of enteropathic strains of Escherichia coli from commensal strains is not possible with present routine bacteriological procedures. Possible adaptations of these experimental techniques to the routine laboratory are discussed. At present, negative-staining electron microscopy is the only way in which reoviruslike particles, the most important viral pathogen in infantile gastroenteritis, may be detected. Because of its relative simplicity this examination is strongly recommended in all cases of infantile gastroenteritis.