Use of a DNA probe to detect Salmonella typhi in the blood of patients with typhoid fever.

A DNA probe was used to detect Salmonella typhi from blood samples from 14 of 33 patients with culture-confirmed typhoid fever, using the equivalent of 2.5 ml of blood. In contrast, S. typhi was detected in 17 of the same 33 patients by culture of 8 ml of blood. The probe hybridized to blood samples of 4 of 47 patients from whom S. typhi was not isolated.