[Study of Legionella pneumophila detection by two step polymerase chain reaction].

We studied the usefulness of two sets of primers in macrophage infectivity potentiator gene sequence of Legionella pneumophila. PCR by 1st step primers produced 649 bp DNA bands and 2nd step primers 489 bp DNA bands. Two step PCR by these primers produced 489 bp DNA bands specific for L. pneumophila. Two step PCR detected 10 fg of pure DNA extracted from L. pneumophila, Philadelphia-1 strain. PCR sensitivity by these primers was superior to former primers reported by us using intratracheal aspirates collected from the patient with L. pneumophila serogroup 2 pneumonia.