Genetic diversity among Borrelia burgdorferi isolates from wood rats and kangaroo rats in California

Abstract

Twenty-nine Borrelia burgdorferi isolates, obtained from dusky-footed wood rats (Neotoma fuscipes) and California kangaroo rats (Dipodomys californicus) in California, were analyzed genetically. Chromosomal DNA was examined by restriction endonuclease analysis (REA) and gene probe restriction fragment length polymorphism. Pulsed-field gel electrophoresis was used to analyze the plasmid profiles of the isolates. REA, the method with the greatest discrimination, disclosed 24 distinct restriction patterns among the 29 isolates. These restriction patterns were sorted into four restriction fragment length polymorphism groups on the basis of their gene hybridization patterns. Results of the REA and plasmid profile analysis supported this grouping. The degree of genetic diversity among Californian isolates demonstrated by our findings is greater than that previously reported among other groups of North American isolates and is similar or greater than the diversity reported among European isolates. Borrelia burgdorferi was first described as a new species in 1984 (23) following its isolation from Ixodes dammini ticks collected on Shelter Island, N.Y. (15). Isolation of a novel, seemingly identical spirochete from the skin (42), blood (10, 42), and cerebrospinal fluid (42) of human patients subsequently confirmed suspicions that this organism was the etiologic agent of Lyme disease. In the past 10 years, Lyme disease has become the most commonly reported vectorborne disease in the United States and Europe, and B.

Three species of Borrelia burgdorferi sensu lato (B. burgdorferi sensu stricto, B afzelii, and B. garinii) identified from cerebrospinal fluid isolates by pulsed-field gel electrophoresis and PCR

“…However, a larger number of strains needs to be analyzed to confirm these results. Our findings of heterogeneity within the B. garinii species ties in with the observations made by using other methods (5,11,12,18,23,30,46,55,56,60).…”

Comparative analysis of genetic variability among Borrelia burgdorferi isolates from Europe and the United States by restriction enzyme analysis, gene restriction fragment length polymorphism, and pulsed-field gel electrophoresis

“…Isolates with these patterns were designated RFLP groups V and VI, respectively. Isolates of RFLP groups II, III, and IV were assigned to fingerprint patterns unique to the Californian isolates (48). The RFLP groupings are listed in Table 1.…”

“…Previously described methods for extraction and purification of Borrelia DNA were used (48). The enzymes were chosen on the basis of information presented in a previous study (26 membrane and hybridized to the cloned 83-kDa antigen gene of B. burgdorferi B31 (28) as described previously (48).…”

“…Pulsed-field gel electrophoresis. Borrelia cells were embedded in plugs of 0.5% low-melting-temperature agarose as described previously (48). The double inhomogeneous electrode array was used, and the point electrodes were set as described previously (26).…”

Species-Specific Plasmid Sequences for PCR Identification of the Three Species of Borrelia burgdorferi Sensu Lato Involved in Lyme Disease

“…In addition, they harbor several circular and linear plasmids. The contribution of plasmids, considered minichromosomes, to the genetic makeup and variability of Borrelia strains has long been recognized (5,8,31,32). In view of the fact that different clinical outcomes depend on the species of the infecting spirochete, the isolation of species-specific sequences might help provide an understanding of the distinct pathogenic mechanisms.…”