Widespread use of real‐time PCR for rickettsial diagnosis

We report 2 years of experience with rickettsial molecular diagnosis using real‐time PCR at the F rench N ational R eference C enter. All R ickettsia genomes available were compared to discover specific sequences to design new sets of primers and probes. The specificity was verified in silico and against a panel of 30 rickettsial species. Sensitivity was determined using 10‐fold serial dilutions. Finally, primers and probes that were both specific and sensitive were routinely used for the diagnosis of rickettsial infections from clinical specimens. We retained sets of primers and probes to detect spotted fever group R ickettsia , typhus group R ickettsia , R ickettsia conorii , R ickettsia slovaca , R ickettsia africae and R ickettsia australis ; 643 clinical samples were screened for the presence of R ickettsia DNA . Overall, 45 positive samples were detected, including 15 R ickettsia africae , nine R . conorii , five R ickettsia sibirica mongolitimonae , four R . slovaca , two R . australis , four R ickettsia massiliae , one R ickettsia honei , one R ickettsia typhi and eight R ickettsia sp. Positive samples were detected mainly from cutaneous biopsies and swabs (31/45). Widespread use of real‐time PCR is inexpensive and reduces delay in the diagnosis of rickettsial infections. These real‐time PCR assays could be implemented easily in laboratories that have molecular facilities and may be added to existing molecular tools as a point‐of‐care strategy.