STUDIES ON A LESION-INDUCING FACTOR OF AVIAN STRAINS OF ESCHERICHIA COLI

Abstract

A lesion-inducing factor (LIF) of virulent avian strains of Escherichia coli was investigated. Liver lesions were produced by concentrated dialyzed filtrates of broth cultures grown at 37 C in a synthetic medium. LIF activity was present in washed cell walls and in extracts from intact cells prepared by a procedure using 1 M NaCl. Extraction with 5 × 10−3 M EDTA alone or in combination with 1 M NaCl also resulted in preparations with satisfactory LIF activity. Preparations obtained by hot water or phenol–water extraction possessed less LIF activity on a weight basis. LIF activity was shown in extracts from three different serogroups of E. coli.