Borrelia

Borreliosis , in the form of louse-borne relapsing fever (LBRF), has been the cause of massive epidemics as recently as the early 1900s. Tick-borne relapsing fever (TBRF) and Lyme borreliosis (LB) are caused by over a dozen Borrelia species and were first described about 100 years ago. There is a high prevalence of B. afzelii among human skin isolates from Europe, whereas isolates from cerebrospinal fluid (CSF) in Europe are most often B. garinii . A few studies have reported the detection of Borrelia species (B. valaisiana , B. spielmanii , and B. lusitaniae ) in patient samples in Europe. The genomes of the borreliae are unusual among prokaryotes in having a small linear chromosome of approximately 1,000 kb and both linear and circular plasmids. Two colinear plasmids (lp54 and cp26) seem to belong to the basic genome inventory of the Borrelia species that causes Lyme disease. The ecological components that maintain Borrelia species in nature are quite diverse and are spread throughout the world. This chapter talks about collection, transport, and storage of specimens. Direct microscopic visualization of borreliae in clinical samples is applicable only to cases of relapsing fever. The chapter describes molecular techniques and immunological techniques for identifying Borrelia species, and explains about the serologic test. The antimicrobial susceptibility of Borrelia species has been studied intensively in vitro. Standard methods for the determination of the minimal bactericidal concentration have not been established. Clinical criteria (case history and clinical findings) are decisive factors in the diagnosis and ordering of microbiological laboratory testing.