Sj. Cutler et al., BORRELIA RECURRENTIS CHARACTERIZATION AND COMPARISON WITH RELAPSING-FEVER, LYME-ASSOCIATED, AND OTHER BORRELIA SPP, International journal of systematic bacteriology, 47(4), 1997, pp. 958-968
Borrelia recurrentis, the cause of louse-borne relapsing fever, has un
til recently been considered noncultivable, which has prevented charac
terization of this spirochete, We successfully cultivated 18 strains f
rom patients with louse-borne relapsing fever and present the initial
characterization of these isolates, Electron microscopy revealed spiro
chetal cells with pointed ends, an average wavelength of 1.8 mu m, an
amplitude of 0.8 mu m, and 8 to 10 periplasmic flagella. The G+C ratio
was 28.4 mol%. Whole DNA-DNA hybridizations showed similarity between
the isolates of B. recurrentis but not with Borrelia hermsii, Borreli
a parkeri, Borrelia turicatae, or the Lyme-associated borreliae. Seque
ncing studies of both the flagellin and 16S RNA genes revealed that th
e greatest similarity was between B. recurrentis and Borrelia duttonii
, Analysis of the sodium dodecyl sulfate-polyacrylamide gel electropho
resis profiles of strains revealed four groups based on tile position
of a major protein hand (one of the groups showed some heterogeneity a
nd was subdivided into four subgroups), Pulsed-field gel electrophores
is revealed five distinct patterns.