PCR and culture were comparatively evaluated far their abilities to demonst
rate Francisella tularensis in wound specimens from tularemia patients duri
ng an outbreak in Sweden in 1998, For transport of the specimens used for P
CR, a buffer solution containing a nuclease inhibitor was used, and for tra
nsport of the specimens used for culture, a commercial transport system was
selected after experimental comparison of various systems. Of 40 patients
with culture- and/or serology-verified ulceroglandular tularemia, PCR detec
ted F. tularensis DNA in 30 (75%) patients, whereas culture detected bacter
ial growth in 25 (62%) patients. Compared to data from a previous study, th
e present inclusion of a nuclease inhibitor in the transport medium did not
improve the sensitivity of the PCR, whereas the sensitivity of the culture
procedure was significantly increased by selection of the system used for
transport, Among eight patients with clinically suspected tularemia but wit
h negative serology and culture, specimens from four patients showed detect
able DNA, In three of these patients the diagnosis was verified by the demo
nstration of an F. tularensis-specific T-cell response in vitro. In conclus
ion PCR was more sensitive than culture for demonstration of F. tularensis
in wound specimens. Besides, we shelved that tularemia may proceed without
development of serum antibodies, and in these patients, PCR may be of speci
al importance for verification of the diagnosis.