A colony blot immunoassay to detect enteroinvasive Escherichia coli and Shigella in water samples.

AIMS: The aim of the study was to develop a colony blot immunoassay to detect Shigella and enteroinvasive Escherichia coli (EIEC) in water.

METHODS AND

RESULTS

Spiked samples were filtered through nitrocellulose membranes. Colony prints on the filters were tested with a monoclonal antibody specific to IpaC, an antigen coded by the invasion plasmid of Shigella and EIEC. Invasive pathogens could be successfully detected with the technique, even in the presence of a large number of non-pathogenic bacterial cells. The method was significantly more sensitive in identifying pathogen-containing samples then the traditional culture-based approach.

CONCLUSION

The IpaC-specific colony blot immunoassay is an inexpensive method for identifying the aetiological agents of bacillary dysentery in water samples.

SIGNIFICANCE AND IMPACT OF THE STUDY: The technique could be particularly useful in detecting enteroinvasive E. coli which often remains undetected by bio- and serotyping.