Comparison of alkaline phosphatase-conjugated oligonucleotide DNA probe with the Sereny test for identification of Shigella strains.

We compared an alkaline phosphatase-conjugated oligonucleotide DNA probe with the Sereny test to determine the sensitivity and specificity of the probe in detecting virulent Shigella strains. The probe hybridized with all 52 Sereny-test-positive strains (sensitivity, 100%) and 4 of 21 Sereny-test-negative strains (specificity, 81%). The probe did not hybridize with any of the Sereny-test-negative S. dysenteriae type 1 strains. This nonradioactive, synthetic probe provides a simple, rapid way to test a large number of strains simultaneously in a field setting, which will contribute to an improved understanding of the epidemiologic patterns of shigellosis in developing countries.