A RAPID, HIGHLY SENSITIVE METHOD FOR THE DETECTION OF FRANCISELLA-TULARENSIS IN CLINICAL-SAMPLES USING THE POLYMERASE CHAIN-REACTION

We have developed a highly sensitive method for detection of Francisel la tularensis in clinical samples based on a nested polymerase chain r eaction (PCR) for the FopA gene. Mice infected with F. tularensis were killed at 24-hr intervals, and the DNA from blood and spleens was ext racted by a variety of methods and analyzed by PCR. The best method, b ased on the ability of DNA to bind to silica in the presence of guanid ine thiocyanate, yielded amplifiable DNA without dilution of the murin e tissues samples. Francisella tularensis in infected murine spleens a nd culture-positive blood samples was reliably detected by nested PCR following this extraction procedure. We believe this technique has sig nificant advantages over traditional methods for diagnosing F. tularen sis infection in terms of speed, ease of use, reproducibility, and saf ety.