Comparison of colony and stool blots for detection of enteropathogens by DNA probes

Abstract

DNA probes that identify genes coding for heat-labile type I (LT-I) and heat-stable type 1 (ST-I) enterotoxins, enteropathogenic Escherichia coli adherence factor (EAF), and Shigella-like invasiveness (INV) are used to evaluate the sensitivity and specificity of stool blots in comparison with the sensitivity and specificity of colony blots in detecting enteropathogens. The sensitivities of the probes in stool blots are 91.7% for the LT-I probe, 76.9% for the ST-I probes, 78.9% for the EAF probe, and 45.5% for the INV probe. The specificity of all probes is higher than 95%. In general, the stool blot method identifies as many if not more LT-I-, ST-I-, and EAF-producing E. coli infections than the colony blots.