Production of Enterobacterial Common Antigen as an Aid to Classification of Newly Identified Species of the Families Enterobacteriaceae and Vibrionaceae

A study on the production of enterobacterial common antigen by recently described or as-yet-undescribed species belonging to the families Enterobacteriaceae and Vibrionaceae was carried out by hemagglutination and hemagglutination inhibition tests with rabbit antisera specific for this antigen. All 28 strains known or presumed to belong to Enterobacteriaceae produced this antigen, and none of the seven strains belonging to Vibrionaceae did so. The results obtained with Tatumella ptyseos and Xenorhabdus species are particularly noteworthy, since they represent species which are atypical for Enterobacteriaceae. It is suggested that the determination of the production of enterobacterial common antigen is a significant aid to classification, particularly when the assignation of a new genus or species to Enterobacteriaceae or to another family presents a problem.