Journal Article

Correlation between Plasmid Content and Infectivity in Borrelia burgdorferi

Steven J. Norris, Joye E. Purser

2000

Overview

Infectivity-associated plasmids were identified in Borrelia burgdorferi B31 by using PCR to detect each of the plasmids in a panel of 19 clonal isolates. The clones exhibited high-, low-, and intermediate-infectivity phenotypes based on their frequency of isolation from needle-inoculated C3H/HeN mice. Presence or absence of 21 of the 22 plasmids was determined in each of the clones by using PCR primers specific for regions unique to each plasmid, as identified in the recently available genome sequence. Southern blot hybridization results were used to confirm the PCR results in some cases. Plasmid Ip25 exhibited a direct correlation with infectivity in that it was consistently present in all clones of high or intermediate infectivity and was absent in all low-infectivity clones. Ip28-1, containing the vmp-like sequence locus, also correlated with infectivity; all clones that lacked Ip28-1 but contained Ip25 had an intermediate infectivity phenotype, in which infection was primarily restricted to the joints. Plasmids cp9, cp32-3, Ip21, Ip28-2, Ip28-4, and Ip56 apparently are not required for infection in this model, because clones lacking these plasmids exhibited a high-infectivity phenotype. Plasmids cp26, cp32-1, cp32-2 and/or cp32-7, cp32-4, cp32-6, cp32-8, cp32-9, Ip17, Ip28-3, Ip36, Ip38, and Ip54 were consistently present in all clones examined. On the basis of these results, Ip25 and Ip28-1 appear to encode virulence factors important in the pathogenesis of B. burgdorferi B31.

• Publisher: National Academy of Sciences of the United States of America,National Acad Sciences,National Academy of Sciences,The National Academy of Sciences
• Subject: Animals / Bacteria / Biological Sciences / Blotting, Southern / Borrelia / Borrelia burgdorferi / Borrelia burgdorferi Group - genetics / Borrelia burgdorferi Group - pathogenicity / Cloning / Gels / Genes / Genomes / Infections / Mice / Mice, Inbred C3H / Microbiology / Phenotype / Phenotypes / Plasma / Plasmid cp26 / Plasmid cp32-1 / Plasmid cp32-2 / Plasmid cp32-3 / Plasmid cp32-4 / Plasmid cp32-6 / Plasmid cp32-7 / Plasmid cp32-8 / Plasmid cp32-9 / Plasmid lp17 / Plasmid lp21 / Plasmid lp25 / Plasmid lp28-2 / Plasmid lp28-3 / Plasmid lp28-4 / Plasmid lp36 / Plasmid lp38 / Plasmid lp54 / Plasmid lp56 / Plasmids / Polymerase Chain Reaction / Spirochaetales / Virulence / Virulence factors / vmp gene