Isolation and characterization of Borrelia burgdorferi strains from Ixodes ricinus ticks in southern England

Abstract

Introduction: Lyme disease is an infectious disease caused by the by spiral-shaped bacterium Borrelia burgdorferi. We investigated the presence and prevalence of Borrelia species in ticks from southern England.
Methods: One hundred fifty-five ticks (103 adult ticks and 52 nymphal ticks) were collected from animal carcases.  The midguts were removed and cultured in Barbour/Stoenner/Kelly II (BSK-II) and Barbour/Stoenner/Kelly F (BSK-F) media, examined by IF, dark-field microscopy, and nested PCR.
Results: From a total 155 cultured ticks, two showed evidence of spirochetes and denoted as SO-1 and SO-2 strains. The availability of these two isolates enabled their antigenic characterization with SDS-PAGE and western blotting and comparison with two standard isolates. These studies identified six protein antigens with molecular weights of 18, 30, 39, 47, 60 and 88 kDa with particular promise for detecting specific immune responses to B. burgdorferi infection including Lyme disease. We also investigated the effect of repeated subculture on the antigenic pattern of UK isolate of B. burgdorferi.
Conclusion: As a result of this study, antigenic differences have been seen between the UK isolates and the foreign isolates used as laboratory standards.

Keywords: Borrelia burgdorferi, Ixodes ricinus ticks, Antigenic variation, Lyme disease