Biochemical properties, enterohaemolysin production and plasmid carriage of Shiga toxin-producing Escherichia coli strains

摘要

Thirty-eight strains of Shiga toxin-producing Escherichia coli (STEC) were characterised in terms of biochemicalproperties, enterohaemolysin production and plasmid carriage. A wide variation in the biochemical properties wasobserved among the STEC, with 14 distinct biotypes identified. Biotype 1 was the most common, found in 29% of the strains. Enterohaemolysinproduction was detected in 29% of the strains. Most of the bacterial strains (95%) carried one or more plasmids and considerable heterogeneityin size and combinations was observed. Seven distinct plasmid profiles were identified. The most common profile, characterised by the presenceof a single plasmid of ~90 kb, was found in 50% of these strains. These data indicate extensive diversity among STEC strains. No correlationwas found among biotype, serotype, enterohaemolysin production and plasmid profile.