Characterization of an exported protease from Shiga toxin-producing Escherichia coli.

The gene for a novel, high molecular weight protein secreted by Shiga toxin-producing Escherichia coli (STEC) has been cloned, sequenced and characterized with respect to its activity. This gene, designated pssA, is localized on the large plasmid that also harbours the STEC haemolysin operon. Sequencing of a region comprising 10630nt revealed that the sequences flanking the pssA gene are composed of several remnants of different insertion elements.

The enterohemolysin phenotype of bovine Shiga-like toxin-producing Escherichia coli (SLTEC) is encoded by the EHEC-hemolysin gene.

Naturally occurring enterohemolysin negative variants were observed during studies on bovine Shiga-like toxin-producing E. coli (SLTEC). Examination of three strains (413/89-1 and 332, 026:H-, and 570/89, O111:H-) and their isogenic variants (413/89-6, 332-I and 570/89-I, respectively) showed, that in each strain loss of the enterohemolytic phenotype correlated with the loss of a large plasmid ranging from 94 to 104 kb in size.