Comparison of rapid methods for detection of heat-labile (LT) and heat-stable (ST) enterotoxin in Escherichia coli.

Oxoid VET-RPLA, ST-EIA and Pharmacia Phadebact ETEC-LT enterotoxin tests were compared to find a simple but reliable method for detecting enterotoxigenic Escherichia coli (ETEC) in Hungary. In the Oxoid tests, all six reference LT- or ST-producing strains, except one ST-producer, gave positive results. Of 11 reference porcine enterotoxigenic strains, all four LT-producers gave positive reactions for LT but three of 10 ST-producers gave negative reactions for ST. Thirteen of 50 strains from culture collections of H. Steinrück (Germany) were LT+ and nine of 33 were ST+. When 31 isolates were tested simultaneously with the Oxoid and the Pharmacia LT tests, 12 strains were LT+ by the Oxoid LT test but by the Phadebact LT test only seven of these strains were LT+ and, of the remainder, three gave uncertain results and two gave negative results. Of 69 porcine strains, seven were LT+ and three ST+. Of 901 human strains isolated in Hungary, 10 were LT+ and one of 24 tested was ST+. In two cases, ETEC strains were isolated from contacts of travellers returning from Mongolia and Bangladesh. Results of comparative studies with reference strains corresponded well to those of the classical toxin detection tests. The Oxoid test was rapid, sensitive, specific and easy to perform and is recommended for use in screening ETEC isolates.

The role in sporadic enteritis of facultatively enteropathogenic Escherichia coli serogroups.

During a two-year period, 2411 faecal specimens and 514 throat swabs were cultured from 1674 persons, mainly infants and children. Of 31 Escherichia coli serogroups considered to represent facultatively enteropathogenic agents, the following were encountered: O4, O18a,b, O18a,c, O19, O20, O25, O28a,b, O32, O51, O53, O75, O78, O79, O105, O112a,c, O114, O115, O117, O129, O143, O145, O148. There was no significant difference in the incidence of the organisms and their serogroup distribution between patients with enteritis, patients with extraintestinal diseases and healthy individuals. A rise of antibody titre in some of the patients indicated an association with enteritis in case of serogropus O4, O18a,c, O19, O25, O75, O78 and O117. It has been assumed that the presence in faeces of a facultatively pathogenic E. coli serogroup does not necessarily prove its aetiological relationship to the disease.

Study of Escherichia coli O114 associated with a hospital outbreak.

Escherichia coli O114 strains isolated from infants in the course of a hospital outbreak of enteritis were identical with type strain 26W in antigenic structure (O114:K90a, 90b), and in immunoelectrophoretic pattern (ORSKOV's group 1Bb) but differed from it in fermenting salicin late (18-22 days) and in phage pattern (group A4); the strains produced colicin and were lysogenic. Pathogenicity of the organism was proved by IgM type antibodies in a patient's serum rising in a titre of 1:128 and by its enterotoxin-producing capacity shown by the rabbit ileal loop assay.