Incidence of enteroinvasive Escherichia coli in Spain. A 14-month prospective study.

: Between February 1984 and May 1985, a prospective study was performed in patients with acute enteritis to determine the incidence of enteroinvasive Escherichia coli (ECEI) in our environment. Eight hundred and forty-three strains of E. coli were studied by agglutination with antisera for serogroups O28ac, 029, 0112, 0124, 0136, 0144, 0152 and 0164. Eleven strains were found to pertain to one or another of these serogroups: 6 to 029, 2 to 0124, 2 to 0164 and 1 to 0143. Of these, only the two corresponding to 0124 invaded HeLa cells and had a positive Sereny test. These strain were lysine decarboxylase and lactose negative and did not produce gas. In 125 strains that did not belong to any of the enteroinvasise serogroups indicated, but had been isolated from patients with febrile enteritis in which no other enteropathogen could be isolated (32 strains), or had metabolic characteristics of enteroinvasive Escherichia coli (93) strains, the Sereny test and invasion of HeLa cells were studied. In every case, both tests were negative.