I'm trying to get a good protocol for PCR on tick DNA extractions for Francisella tularensis. Does anybody have any good suggestions? I've seen a couple but mostly multiplex reactions, and nothing that seems very highly cited.
it depends in what kind of Francisella species/subspecies you are interested in. F. tularenis subsp. tularensis (Jelllison type A) or F. tul subsp. holarctica (type B). Or do you want to screen for all Francisella species?
For a rapid, simple and highly sensitive Screening we used a Francisella genus specific realtime PCR targeting the 16S rDNA genes (F.t. has three copies): See
(Presence of an emerging subclone of Francisella tularensis holarctica in Ixodes ricinus ticks from south-western Germany. Gehringer H, Schacht E, Maylaender N, Zeman E, Kaysser P, Oehme R, Pluta S, Splettstoesser WD. Ticks Tick Borne Dis. 2013 Feb;4(1-2):93-100. doi: 10.1016/j.ttbdis.2012.09.001. Epub 2012 Nov 7.)
There is ready to use PCR kit available from the Company TibMolBiol, Berlin.
You should keep in mind, that different tick species may harbor Francisella like endosymbionts which very often give false positive results with a lot of PCR protocols developed to detect F. tularensis.
Thanks a bunch, we have both type A and type B here, so I'm thinking I will have to screen for both and potentially sequence to distinguish from endosymbionts. I will check out the paper, thank you so much.