Retention of enteropathogenicity by viable but nonculturable Escherichia coli exposed to seawater and sunlight

Enterotoxigenic strains of Escherichia coli H10407 retain pathogenicity even after being exposed to sunlight, and entering the viable but nonculturable state. When exposed to sunlight, the direct counts of viable cells fail to change. Escherichia coli cells are culturable in the absence of sunlight only when exposed to seawater. Ganglioside-enzyme-linked immunosorbent assay (GM1-ELISA) shows that Escherichia coli continues to produce enterotoxin after exposure to sunlight. GM1-ELISA is found to be superior to the conventional rabbit intestinal loop assay.