[Antigenic relations between enteropathogenic Escherichia O151:K, Citrobacter and Hafnia]

The strains isolated from acute dysentery patients and convalescents and identified as E. coli O151:K--were studied. Diagnostic errors due to inexact genus determination were revealed, and the isolated strains were found to belong to Citrobacter and Hafnia. The main biochemical differences allowing to differentiate E. coli O151:K--from these two genera were established. The study also showed the necessity of some tests, such as the tests for citrate assimilation in Simmons' medium and sodium malonate assimilation, the determination of indole production, the determination of differences in the methyl red and Voges--Proskauer reactions at different temperatures. The poor unilateral antigenic relationship of the strains under study, agglutinating with antiserum to E. coli O151, Citrobacter O1 and O14 and Hafnia C18 was revealed.