ELISA for detection of heat stable enterotoxin producing Escherichia coli strains

Among 557 strains of Esch. coli isolated from patients with acute diarrhoea, 392 (70.4%) isolates demonstrated ST production by ELISA. Predominant ST producing serogroups were 020 (45), 078 (40), 0128 (21), 061 (19), 0149 (9), 04, 055, 0106 and 0114 (8 each). The inhibition ELISA range was between 10.5 and 40.5 per cent. Visual difference between a negative and a positive ELISA test was distinct. A comparison of ELISA with classical suckling mouse assay for 100 strains showed 88 and 80 positive strains respectively for ST. ELISA proved a more specific, rapid and sensitive assay which may be useful for screening large number of isolates in epidemiological studies.