Four clones of Borrelia burgdorferi sensu stricto cause invasive infection in humans.
Lyme disease begins at the site of a tick bite, producing a primary infection with spread of the organism to secondary sites occurring early in the course of infection. A major outer surface protein expressed by the spirochete early in infection is outer surface protein C (OspC). In Borrelia burgdorferi sensu stricto, OspC is highly variable. Based on sequence divergence, alleles of ospC can be divided into 21 major groups. To assess whether strain differences defined by ospC group are linked to invasiveness and pathogenicity, we compared the frequency distributions of major ospC groups from ticks, from the primary erythema migrans skin lesion, and from secondary sites, principally from blood and spinal fluid. The frequency distribution of ospC groups from ticks is significantly different from that from primary sites, which in turn is significantly different from that from secondary sites. The major groups A, B, I, and K had higher frequencies in the primary sites than in ticks and were the only groups found in secondary sites. We define three categories of major ospC groups: one that is common in ticks but very rarely if ever causes human disease, a second that causes only local infection at the tick bite site, and a third that causes systemic disease. The finding that all systemic B. burgdorferi sensu stricto infections are associated with four ospC groups has importance in the diagnosis, treatment, and prevention of Lyme disease. (+info)
Detection of Borrelia burgdorferi sensu stricto by reverse line blot in the joints of Dutch patients with Lyme arthritis.
OBJECTIVE: To analyze the presence of Borrelia burgdorferi sensu lato in synovial samples from the knee joint of patients with Lyme arthritis by polymerase chain reaction, and to differentiate the species by reverse line blot (RLB). METHODS: Synovial fluid (SF) and synovial tissue (ST) samples were obtained from patients with Lyme arthritis (n = 4) and from patients with various other forms of arthritis (n = 9). DNA extracted from synovial samples was amplified by using, as a target, the spacer region between the 5S and 23S ribosomal RNA genes of B. burgdorferi sensu lato. Subsequently, 4 species-specific DNA probes were used in the RLB for specific hybridization. RESULTS: DNA from B. burgdorferi sensu stricto DNA was detected in the SF and ST from 3 patients with Lyme arthritis. B. burgdorferi sensu lato DNA was not detected in the synovial samples from 9 control patients. CONCLUSION: The relationship between different species of B. burgdorferi sensu lato and arthritis can be studied using direct analysis of extracted DNA from joint samples. This method can be used to study the association between particular clinical manifestations of Lyme disease and different species of B. burgdorferi sensu lato. (+info)
Scored antibody reactivity determined by immunoblotting shows an association between clinical manifestations and presence of Borrelia burgdorferi sensu stricto, B. garinii, B. afzelii, and B. Valaisiana in humans.
An immunoglobulin G immunoblot was developed with antigenic extracts of Borrelia burgdorferi sensu stricto, B. garinii, B. afzelii, and B. valaisiana genospecies and was reacted with sera from patients with neuroborreliosis, acrodermatitis, and Lyme arthritis. A detailed analysis of the reactivities of the protein bands was performed, and a two-step scoring procedure was selected to determine the preferential reactivity of sera to one particular genospecies. The discriminative potential of 5 proteins (12-kDa, 16-kDa, 18-kDa, OspA, and 66-kDa proteins) was used as a rapid first-step scoring method, followed by scoring of 14 additional protein bands if necessary. The advantage of this procedure is the low percentage of serum samples with inconclusive results for one of the four species (10% for patients with neuroborreliosis, 6% for patients with acrodermatitis chronica atrophicans, and 6% for patients with Lyme arthritis). Among 31 serum samples from patients with neuroborreliosis, 16 were more reactive to B. garinii, 7 were more reactive to B. afzelii, 3 were more reactive to B. valaisiana, and 2 were more reactive to B. burgdorferi sensu stricto. Of 31 serum samples from patients with acrodermatitis, 26 showed a higher level of reactivity to B. afzelii. Of 34 serum samples from patients with Lyme arthritis, 21 were more reactive to B. burgdorferi sensu stricto, 10 were more reactive to B. afzelii, and 1 was more reactive to B. valaisiana. Our results suggest an organotropism of Borrelia species and provide some evidence of a pathogenic potential of B. valaisiana in humans. (+info)
Temporal changes in outer surface proteins A and C of the lyme disease-associated spirochete, Borrelia burgdorferi, during the chain of infection in ticks and mice.
The Lyme disease-associated spirochete, Borrelia burgdorferi, is maintained in enzootic cycles involving Ixodes ticks and small mammals. Previous studies demonstrated that B. burgdorferi expresses outer surface protein A (OspA) but not OspC when residing in the midgut of unfed ticks. However, after ticks feed on blood, some spirochetes stop making OspA and express OspC. Our current work examined the timing and frequency of OspA and OspC expression by B. burgdorferi in infected Ixodes scapularis nymphs as they fed on uninfected mice and in uninfected I. scapularis larvae and nymphs as they first acquired spirochetes from infected mice. Smears of midguts from previously infected ticks were prepared at 12- or 24-h intervals following attachment through repletion at 96 h, and spirochetes were stained for immunofluorescence for detection of antibodies to OspA and OspC. As shown previously, prior to feeding spirochetes in nymphs expressed OspA but not OspC. During nymphal feeding, however, the proportion of spirochetes expressing OspA decreased, while spirochetes expressing OspC became detectable. In fact, spirochetes rapidly began to express OspC, with the greatest proportion of spirochetes having this protein at 48 h of attachment and then with the proportion decreasing significantly by the time that the ticks had completed feeding. In vitro cultivation of the spirochete at different temperatures showed OspC to be most abundant when the spirochetes were grown at 37 degrees C. Yet, the synthesis of this protein waned with continuous passage at this temperature. Immunofluorescence staining of spirochetes in smears of midguts from larvae and nymphs still attached or having completed feeding on infected mice demonstrated that OspA but not OspC was produced by these spirochetes recently acquired from mice. Therefore, the temporal synthesis of OspC by spirochetes only in feeding ticks that were infected prior to the blood meal suggests that this surface protein is involved in transmission from tick to mammal but not from mammal to tick. (+info)
The relapsing fever spirochete Borrelia hermsii contains multiple, antigen-encoding circular plasmids that are homologous to the cp32 plasmids of Lyme disease spirochetes.
Borrelia hermsii, an agent of tick-borne relapsing fever, was found to contain multiple circular plasmids approximately 30 kb in size. Sequencing of a DNA library constructed from circular plasmid fragments enabled assembly of a composite DNA sequence that is homologous to the cp32 plasmid family of the Lyme disease spirochete, B. burgdorferi. Analysis of another relapsing fever bacterium, B. parkeri, indicated that it contains linear homologs of the B. hermsii and B. burgdorferi cp32 plasmids. The B. hermsii cp32 plasmids encode homologs of the B. burgdorferi Mlp and Bdr antigenic proteins and BlyA/BlyB putative hemolysins, but homologs of B. burgdorferi erp genes were absent. Immunoblot analyses demonstrated that relapsing fever patients produced antibodies to Mlp proteins, indicating that those proteins are synthesized by the spirochetes during human infection. Conservation of cp32-encoded genes in different Borrelia species suggests that their protein products serve functions essential to both relapsing fever and Lyme disease spirochetes. Relapsing fever borreliae replicate to high levels in the blood of infected animals, permitting direct detection and possible functional studies of Mlp, Bdr, BlyA/BlyB, and other cp32-encoded proteins in vivo. (+info)
Rapid differentiation of Borrelia garinii from Borrelia afzelii and Borrelia burgdorferi sensu stricto by LightCycler fluorescence melting curve analysis of a PCR product of the recA gene.
To differentiate the Borrelia burgdorferi sensu lato genospecies, LightCycler real-time PCR was used for the fluorescence (SYBR Green I) melting curve analysis of borrelial recA gene PCR products. The specific melting temperature analyzed is a function of the GC/AT ratio, length, and nucleotide sequence of the amplified product. A total of 32 DNA samples were tested. Of them three were isolated from B. burgdorferi reference strains and 16 were isolated from B. burgdorferi strains cultured from Ixodes ricinus ticks; 13 were directly isolated from nine human biopsy specimens and four I. ricinus tick midguts. The melting temperature of B. garinii was 2 degrees C lower than that of B. burgdorferi sensu stricto and B. afzelii. Melting curve analysis offers a rapid alternative for identification and detection of B. burgdorferi sensu lato genospecies. (+info)
Crystal structure of outer surface protein C (OspC) from the Lyme disease spirochete, Borrelia burgdorferi.
Outer surface protein C (OspC) is a major antigen on the surface of the Lyme disease spirochete, Borrelia burgdorferi, when it is being transmitted to humans. Crystal structures of OspC have been determined for strains HB19 and B31 to 1.8 and 2.5 A resolution, respectively. The three-dimensional structure is predominantly helical. This is in contrast to the structure of OspA, a major surface protein mainly present when spirochetes are residing in the midgut of unfed ticks, which is mostly beta-sheet. The surface of OspC that would project away from the spirochete's membrane has a region of strong negative electrostatic potential which may be involved in binding to positively charged host ligands. This feature is present only on OspCs from strains known to cause invasive human disease. (+info)
Impact of genotypic variation of Borrelia burgdorferi sensu stricto on kinetics of dissemination and severity of disease in C3H/HeJ mice.
Various genotypes of Borrelia burgdorferi sensu stricto have been previously identified among a large collection of isolates cultured from patients with Lyme disease in the United States. Furthermore, association of specific genotypes with hematogenous dissemination early in the disease course has been observed. The present study assessed kinetics of spirochete dissemination and disease severity in C3H/HeJ mice infected with two different genotypes of B. burgdorferi. Spirochete load in plasma and ear and other tissue samples of infected mice was measured by quantitative PCR, and these data were compared to those obtained by culture and histopathologic analysis. In mice infected with isolate BL206 (a type 1 strain), the peak number of spirochetes was observed in plasma between day 4 and 7, in heart and ear tissue on day 14, and in joints on day 28 postinoculation. There was a correlation between the peak number of spirochetes in plasma on day 4 or 7 and that in ear biopsy and joint specimens on day 14. By contrast, spirochete burdens in plasma of mice infected with isolate B356 (a type 3 strain) were 16- and 5-fold lower than those of BL206-infected mice on days 7 and 14 of infection, respectively. Similarly, approximately 6- and 13-fold fewer spirochetes were detected in the heart tissues of B356-infected mice compared to BL206-infected mice. Histopathologically, severe arthritis and aortitis were noted only in mice infected with isolate BL206. Spirochete dissemination and disease severity vary significantly in mice infected with distinct genotypes of B. burgdorferi, suggesting that genotypic differences in the infecting spirochetes play a key role in the pathogenesis and development of clinical disease. (+info)