Soluble Antigens Of Enteropathogenic Escherichia Coli

An immuno-electrophoretic procedure is described for the detection of soluble bacterial antigens in culture extracts, and in material from ligated rabbit gut loops. All material examined in this study was derived from fully identified strains of Escherichia coli and rabbit gut loop exudates. A precipitin line, referred to as line 1, was produced when antisera (L sera) prepared with living vaccines were tested in the system against E. coli-induced gut exudates or extracts of cultures that evoked gut exudates. Rabbit antisera prepared in response to dead vaccines (D sera) of strains known to be enterotoxic to man did not produce line 1, nor was this precipitin band produced when L sera were tested against (i) the media used, (ii) normal rabbit gut washings, or (iii) extracts of E. coli that failed to dilate rabbit gut.

This study was extended to a survey of strains of E. coli isolated from healthy babies, from babies with diarrhoea, from urinary tract infections and other sources in man, and from various species of animals.

Line 1 was never produced by extracts of strains of E. coli isolated from the following human material: 39 faecal strains from healthy babies, 17 strains from infected urines, 2 strains from vaginal swabs and 1 from a sample of cerebrospinal fluid; nor was line 1 produced by 24 strains of animal origin. Ninety-nine of the 316 strains isolated from the faeces of babies with diarrhoea and 1 strain isolated from the faeces of a scouring calf produced line 1.