Detection of established virulence genes and plasmids to differentiate Borrelia burgdorferi strains

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Detection of established virulence genes and plasmids to differentiate Borrelia burgdorferi strains

Kamfai Chan 1,
Sherwood Casjens 2 and
Nikhat Parveen1,*

+ Author Affiliations

1 -Department of Microbiology and Molecular Genetics, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, 225 Warren Street, Newark, NJ 07103-3535,USA


2 -Division of Microbiology and Immunology, Department of Pathology, University of Utah Medical School, Salt Lake City, UT 84112



ABSTRACT

Borrelia burgdorferi sensu stricto is the major causative agent of Lyme disease in the United States while B. garinii and B. afzelii are more prevalent in the Europe. The highly complex genome of B. burgdorferi is comprised of a linear chromosome and a large number of variably sized linear and circular plasmids. Many plasmids of this spirochete are unstable during its culture in vitro. Given that many of the B. burgdorferi virulence factors identified to date are plasmid-encoded, spirochetal plasmid content determination is essential for genetic analysis of Lyme pathogenesis. Although Polymerase Chain Reaction (PCR)-based assays facilitate plasmid profiling of sequenced B. burgdorferi strains, the rapid genetic content determination strategy for non-sequenced strains has not been described yet. In this study, we combined pulse field gel electrophoresis and Southern hybridization for detection of genes encoding known virulence factors, ribosomal DNA spacer restriction fragment length polymorphism types (RST), ospC group determination, and sequencing of the variable dbpA and ospC genes. We show that two strains isolated from the same tick and both originally named N40, are in fact very distinct. Furthermore, we failed to detect bbk32, which encodes a fibronectin-binding adhesin in one “N40” strain. Thus, two distinct strains were isolated from the same tick that show different plasmid profile as determined by PFGE and PCR and vary in their ospC and dbpA sequence. However, both belong to RST3B group.



FOOTNOTES
↵*Corresponding Author: Nikhat Parveen, Tel: 973 972 4483x25218; Fax: 973 972 8981; E-mail: Parveeni@umdnj.edu
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