Molecular typing of Borrelia burgdorferi sensu lato: taxonomic, epidemiological, and clinical implications

Improved laboratory diagnostics of Lyme neuroborreliosis in children by detection of antibodies to new antigens in cerebrospinal fluid

BACKGROUND

Laboratory diagnostics in Lyme neuroborreliosis need improvement. We hereby investigate 4 new recombinant or peptide Borrelia antigens in cerebrospinal fluid in children with neuroborreliosis to evaluate their performance as diagnostic antigens.

METHODS

An enzyme-linked immunosorbent assay was used to detect IgG antibodies to recombinant decorin binding protein A (DbpA), BBK32, outer surface protein C (OspC), and the invariable region 6 peptide (IR6). The recombinant antigens originated from 3 pathogenic subspecies; Borrelia afzelii, Borrelia garinii, and Borrelia burgdorferi sensu stricto. Cerebrospinal fluid and serum from children with clinical features indicative for neuroborreliosis (n = 57) were analyzed. Classification of patients was based on clinical symptoms and laboratory findings. Controls were children with other neurologic diseases (n = 20) and adult patients with no proven infection (n = 16).

RESULTS

Sensitivity for DbpA was 82%, for BBK32 70%, for OspC 58% and for IR6 70%. Specificities were 94%, 100%, 97%, and 97%, respectively. No single antigen was superior. When new antigens were combined in a panel, sensitivity was 80% and specificity 100%. The reference flagella antigen showed a sensitivity of 60% and a specificity of 100%. Over all, the B. garinii related antigens dominated.

CONCLUSIONS

Recombinant DbpA and BBK32 as well as the peptide antigen IR6 perform well in laboratory diagnostics of neuroborreliosis in children. New antigens seem to improve diagnostic performance when compared with the routine flagella antigen. If different antigens are combined in a panel to cover the antigenic diversity, sensitivity improves further and a specificity of 100% can be achieve.

Epidemiological aspects and molecular characterization of Borrelia burgdorferi s.l. from southern Germany with special respect to the new species Borrelia spielmanii sp. nov

In 475 Borrelia-infected Ixodes ricinus (2155 ticks investigated) from southern Germany the most common Borrelia burgdorferi sensu lato species was B. garinii (34.3%) followed by B. afzelii (25.1%), B. burgdorferi sensu stricto (22.0%), and B. valaisiana (12.7%). B. spielmanii sp. nov. was detected in 5.9% of the 475 infected ticks. Hints for a focal distribution were found for B. spielmanii sp. nov. and B. garinii OspA type 4. In 242 patient isolates, dominance (66.9%) of B. afzelii for skin could be confirmed, while frequency of B. garinii in cerebrospinal fluid (CSF) isolates (51.1%) was comparable to the frequency in nymphal ticks (51.6%). Four patient isolates from southern Germany and two from Slovenia, all isolated from erythema migrans, could be assigned to B. spielmanii sp. nov. Within this new species high sequence identities were found for rrs, fla, and ospA while rrf-rrl, ospC, and dbpA were less conserved: three new ospC and two new dbpA sequence types were found. This genetic heterogeneity reveals that B. spielmanii sp. nov. did not evolve just recently.

Borrelia burgdorferi complement regulator-acquiring surface protein 2 (CspZ) as a serological marker of human Lyme disease

Serological diagnosis of Lyme disease may be complicated by antigenic differences between infecting organisms and those used as test references. Accordingly, it would be helpful to include antigens whose sequences are well conserved by a broad range of Lyme disease spirochetes. In the present study, line blot analyses were performed using recombinant complement regulator-acquiring surface protein 2 (BbCRASP-2) from Borrelia burgdorferi sensu stricto strain B31 and serum samples from human Lyme disease patients from throughout the United States and Germany. The results indicated that a large proportion of the patients had produced antibodies recognizing recombinant BbCRASP-2. In addition, Lyme disease spirochetes isolated from across North America and Europe were found to contain genes encoding proteins with high degrees of similarity to the B. burgdorferi type strain B31 BbCRASP-2, consistent with the high percentage of serologically positive patients. These data indicate that BbCRASP-2 may be valuable for use in a widely effective serological assay.

Borrelia burgdorferi VlsE antigen for the serological diagnosis of Lyme borreliosis

In this study, raising and development of antibody response to Borrelia burgdorferi infection in 66 Italian patients suffering from culture-confirmed Lyme borreliosis erythema migrans (EM) was investigated. Sixty-two of 66 cultures obtained from biopsies were identified as B. afzelii by PCR. A total of 175 serially collected serum samples were tested by using two different sets of commercial assays: Enzygnost Lyme link VlsE/IgG and Enzygnost Borreliosis IgM (DADE Behring, Marburg, Germany) and LIAISON Borrelia IgG and IgM (Diasorin, Saluggia, Italy). Considering only samples obtained at first presentation when EM was clinically evident, 49/66 patients (72.4%) were IgG or IgM positive by Enzygnost, whereas 33/66 (50.0%) patients were IgG or IgM positive by LIAISON. Taking into account the follow-up period, eight patients sero-converted for IgG or IgM by Enzygnost and four by LIAISON. Similar and very good specificity values were obtained by all methods. Testing sera obtained from blood donors (n = 300) and from patients suffering from some of the most common biological conditions possibly resulting in false-positive reactivity in Lyme disease serology (n = 100) showed that Enzygnost Lyme link VlsE/IgG was the more specific (98.3%), followed by LIAISON Borrelia IgG (96.5%), and considering IgM tests, Enzygnost Borreliosis IgM showed to be 95.3%% specific, whereas the LIAISON Borrelia IgM was 92.8% specific. Recombinant VlsE antigens obtained from all three B.burgdorferi genospecies pathogenic to humans (included in Enzygnost Lyme link VlsE/IgG) greatly improved serodiagnosis of Lyme disease.

Prevention of tick-borne diseases

Tick-borne diseases are on the rise. Lyme borreliosis is prevalent throughout the Northern Hemisphere, and the same Ixodes tick species transmitting the etiologic agents of this disease also serve as vectors of pathogens causing human babesiosis, human granulocytic anaplasmosis, and tick-borne encephalitis. Recently, several novel agents of rickettsial diseases have been described. Despite an explosion of knowledge in the fields of tick biology, genetics, molecular biology, and immunology, transitional research leading to widely applied public health measures to combat tick-borne diseases has not been successful. Except for the vaccine against tick-borne encephalitis virus, and a brief campaign to reduce this disease in the former Soviet Union through widespread application of DDT, success stories in the fight against tick-borne diseases are lacking. Both new approaches to tick and pathogen control and novel ways of translating research findings into practical control measures are needed to prevent tick-borne diseases in the twenty-first century.

[Lyme arthritis, Lyme carditis and other presentations potentially associated to Lyme disease]

Lyme disease or Lyme borreliosis is the most common tick-transmitted disease in the Northern hemisphere and is caused by Borrelia burgdorferi spirochetes. Lyme disease commonly begins with a characteristic skin lesion, erythema migrans. Weeks or months later, the patients may have neurologic, joint, or cardiac abnormalities. Some patients may still present persistent deep fatigue and various unspecific symptoms after standard courses of antibiotic treatment for Lyme disease. This constellation of symptoms has been variously referred to as "chronic Lyme disease", or "post-Lyme disease syndrome". The first French National Consensus Conference on Lyme Disease was the reason to review all aspects of articular and cardiac manifestations of Lyme disease after a synthesis of recent literature. The involvement of Borrelia species in chronic Lyme disease and other pathologies is discussed.

Tick-host-pathogen interactions in Lyme borreliosis

Borrelia burgdorferi, the spirochetal agent of Lyme borreliosis, is predominantly transmitted by Ixodes ticks. Spirochetes have developed many strategies to adapt to the different environments that are present in the arthropod vector and the vertebrate host. This review focuses on B. burgdorferi genes that are preferentially expressed in the tick and the vertebrate host, and describes how selected gene products facilitate spirochete survival throughout the enzootic life cycle. Interestingly, B. burgdorferi also enhances expression of specific Ixodes scapularis genes, such as TROSPA and salp15. The importance of these genes and their products for B. burgdorferi survival within the tick, and during the transmission process, will also be reviewed. Moreover, we discuss how such vector molecules could be used to develop vector-antigen-based vaccines to prevent the transmission of B. burgdorferi and, potentially, other arthropod-borne microbes.

Lyme meningoradiculitis: prospective evaluation of biological diagnosis methods

The symptoms of Lyme meningoradiculitis and the value of biological examinations in an endemic area were determined in a prospective study in which data were collected on all patients consecutively hospitalised for Lyme meningoradiculitis at our institution during an 18-month period. Specific antibody titres in the serum and cerebrospinal fluid (CSF) were determined by Vidas enzyme-linked-immunosorbent-assay (IgG + IgM), Dade-Behring enzyme immunoassay (EIA) (IgM; IgG) and Western blot analysis (IgG). We also searched for Borrelia burgdorferi in the CSF by PCR analysis and following culture on a specific medium. A control group was recruited, consisting of 16 consecutive patients who had been referred during the same period with suspected but not confirmed Lyme meningoradiculitis. Eleven patients were included. Borrelia EIA of the serum revealed that 40% of the patients had both elevated specific IgM titres and intrathecal synthesis of specific IgG; 40% of the patients was negative for IgM but had isolated intrathecal synthesis of IgG; 20% of the patients had elevated specific IgM titres without intrathecal synthesis of IgG. PCR analysis and the CSF culture were positive in one case only (B. garinii). The results of this study highlight the importance of systematic serological testing for B. burgdorferi in the CSF in the case of early neuroborreliosis suspicion, even in the absence of IgM serum antibodies, which was the case in 40% of the patients in the present study. Nevertheless, intrathecal anti-B. burgdorferi IgG synthesis, which remains the "gold standard" for the diagnosis of neuroborreliosis, was not detectable in 20% of the patients for whom diagnosis was subsequently confirmed by demonstration of specific serum IgM.

Lyme neuroborreliosis: infection, immunity, and inflammation

Lyme neuroborreliosis (LNB), the neurological manifestation of systemic infection with the complex spirochaete Borrelia burgdorferi, can pose a challenge for practising neurologists. This Review is a summary of clinical presentation, diagnosis, and therapy, as well as of recent advances in our understanding of LNB. Many new insights have been gained through work in experimental models of the disease. An appreciation of the genetic heterogeneity of the causative pathogen has helped clinicians in their understanding of the diverse presentations of LNB.

A reverse transcriptase-polymerase chain reaction assay of Borrelia burgdorferi 16S rRNA for highly sensitive quantification of pathogen load in a vector

We developed a real-time quantitative detection assay for the pathogen Borrelia burgdorferi, a Lyme borreliosis (LB) agent, using reverse transcription-polymerase chain reaction (RT-PCR) with primers and probe for a Borrelia genus-specific region of 16S ribosomal RNA. The standard curve of the assay was linear by semi-log plot over more than five orders of magnitude, and the detection limit of the assay was one thousandth of a single cell of B. burgdorferi. The minimum target level for detection using the RT-PCR assay for 16S RNA was 40-fold lower than the RT-PCR assay for messenger RNA of ospA, a highly expressed, plasmid-borne gene, and 1600-fold lower than the RT-PCR assay for messenger RNA of p66, a chromosome-borne gene of B. burgdorferi. The 16S rRNA assay was then applied in an experimental setting for monitoring the spirochetal load in B. burgdorferi-infected Ixodes scapularis ticks before and after they fed on Peromyscus leucopus mice immunized with recombinant OspA. Unfed infected ticks had a mean of 2,240 spirochetes per tick, and after feeding on non-immunized mice and engorgement, the mean number of spirochetes increased to 223,900 per tick. In contrast, there were either no or <or=7 spirochetes in ticks that had fed on OspA-immunized mice.

Microbiological and serological diagnosis of Lyme borreliosis

In Europe, Lyme borreliosis is caused by Borrelia burgdorferi sensu stricto, B. afzelii, B. garinii and the recently described species B. spielmanii. For the development of diagnostic tools, the heterogeneity of the causative agents must be considered. The serological diagnosis should follow the principle of a two-step procedure: a sensitive enzyme-linked immunosorbent analysis as the first step, followed by immunoblot (IgM and IgG) if reactive. The sensitivity and standardization of immunoblots have been enhanced by the use of recombinant antigens instead of whole cell lysates. Improved sensitivity has resulted from the use of recombinant proteins primarily expressed in vivo (e.g. VlsE) and the combination of homologous proteins from different strains (e.g. DbpA). At present, detection rates for serum antibodies are 20-50% in localized, 70-90% in disseminated early and nearly 100% in late disease. Detection of the borreliae by culture or PCR should be confined to specific indications. The best results are obtained from skin biopsies (50-70% with culture or PCR) and synovial tissue or fluid (50-70% with PCR). Cerebrospinal fluid is positive in only 10-30%. Methods that are not recommended for diagnostic purposes include antigen tests in body fluids, PCR of urine and lymphocyte transformation tests.

Complementation of a Borrelia afzelii OspC mutant highlights the crucial role of OspC for dissemination of Borrelia afzelii in Ixodes ricinus

Alteration of the outer surface protein (Osp) composition--especially that of OspA and OspC--seems to be important for the adaptation of Borrelia burgdorferi sensu lato to its endothermic hosts (mammals) and poikilothermic vectors (ticks). OspA possibly mediates adherence to tick midgut cells thus enabling the borreliae to survive in the vector, while OspC is associated with borrelial invasion of the tick salivary glands and infection of the mammalian hosts. Here we describe the first successful transformation and complementation of a Borrelia afzelii ospC mutant with the wild-type ospC in trans. To test the influence of OspC on the dissemination behavior in ticks, unfed Ixodes ricinus nymphs were artificially infected by capillary feeding either with B. afzelii wild type, the B. afzelii ospC mutant or the ospC-complemented clone. Tick midguts and salivary glands were investigated after different time intervals for the presence of borreliae and for OspA and OspC by immunfluorescence staining with monoclonal antibodies. While the B. afzelii wild-type strain exhibiting abundant OspC on its surface disseminated to the salivary glands, the OspC-negative mutant was only present in the tick midguts. The ospC-complemented clone which constitutively expresses the wild-type ospC was again able to colonize the salivary glands. This finding demonstrates that OspC is crucial for dissemination of B. afzelii from the tick midgut to the salivary glands, a prerequisite for infection of the warm-blooded host. A summary of the detailed data presented here has already been given in Goettner et al. [2006. OspC of B. afzelii is crucial for dissemination in the vector as shown by transformation and complementation of a European OspC-deficient B. afzelii strain. Int. J. Med. Microbiol. 296S1(Suppl. 40), 122-124].

Antigenicity of borrelial protein BBK32 fragments in early Lyme borreliosis

Recombinantly produced borrelial BBK32 protein fragments originating from Borrelia burgdorferi sensu stricto, Borrelia garinii and Borrelia afzelii were evaluated as antigens in the serology of Lyme borreliosis (LB). In ELISA, a mid-portion hydrophilic fragment reacted with LB patient sera. Of the 23 patients with culture- or PCR-positive erythema migrans (EM), 43 % at diagnosis and 52 % at convalescence were positive for at least one Borrelia species-specific variant BBK32 fragment antigen. In parallel ELISAs with BBK32 whole proteins from the three borrelial subspecies as antigens, 17 % at diagnosis and 26 % at convalescence were positive. These results suggest that BBK32 protein fragments may improve the early IgG serology of LB compared to the BBK32 whole protein.

Borrelia lusitaniae and green lizards (Lacerta viridis), Karst Region, Slovakia

In Europe, spirochetes within the Borrelia burgdorferi sensu lato complex are transmitted by Ixodes ricinus ticks. Specific associations are described between reservoir hosts and individual genospecies. We focused on green lizard (Lacerta viridis) as a host for ticks and potential host for borreliae. In 2004 and 2005, a total of 146 green lizards infested by ticks were captured, and 469 I. ricinus ticks were removed. Borrelial infection was detected in 16.6% of ticks from lizards. Of 102 skin biopsy specimens collected from lizards, 18.6% tested positive. The most frequently detected genospecies was B. lusitaniae (77.9%-94.7%). More than 19% of questing I. ricinus collected in areas where lizards were sampled tested positive for borreliae. B. garinii was the dominant species, and B. lusitaniae represented 11.1%. The presence of B. lusitaniae in skin biopsy specimens and in ticks that had fed on green lizards implicates this species in the transmission cycle of B. lusitaniae.

Comparison of immunofluorescence assay (IFA) and LIAISON® in patients with different clinical manifestations of Lyme borreliosis

Serological tests for detection of borrelial antibodies are frequently used in laboratory diagnostics of Lyme borreliosis. Unfortunately these tests are not standardized and the results obtained with different assays may not be concordant. The aim of the present study was to compare two different serological tests, IFA and LIAISON, for detection of Borrelia burgdorferi sensu lato IgM and IgG antibody. We analyzed the serological immune response in 383 patients with different clinical manifestations of Lyme borreliosis and in 49 healthy blood donors. LIAISON detected IgM and IgG antibodies more often than IFA in all groups of patients except those with chronic Lyme borreliosis. The differences were significant for IgM and IgG antibodies in patients with solitary erythema migrans and in those with early disseminated Lyme borreliosis. There was no significant difference in the specificity of the two tests.

Evaluation of an internally controlled real-time PCR targeting the ospA gene for detection of Borrelia burgdorferi sensu lato DNA in cerebrospinal fluid

This study reports the development and evaluation of an internally controlled real-time PCR targeting the ospA gene for detection of Borrelia burgdorferi sensu stricto, Borrelia garinii, Borrelia afzelii and Borrelia valaisiana. DNA was extracted using QIAamp DNA Blood Mini kit columns. DNA from 33 B. burgdorferi sensu lato strains reacted in the assay, whereas no reactivity was observed with DNA from four relapsing fever Borrelia spp., 11 unrelated spirochaetes, and 31 unrelated microorganisms. The quantitative sensitivity of the assay was 1-10 fg of Borrelia DNA and one to five cultured Borrelia spirochaetes. Cerebrospinal fluid (CSF) specimens from 70 patients sent for routine testing for neuroborreliosis, and three CSF specimens containing B. garinii were also tested. Positive PCR results were obtained with all three culture-confirmed neuroborreliosis specimens, five of ten neuroborreliosis specimens with specific antibodies in CSF and pleocytosis, none of nine specimens from possible cases of early neuroborreliosis (antibodies in serum, CSF pleocytosis, no antibodies in CSF), one of 15 specimens from patients with active or past Lyme disease with neurological signs (antibodies in serum, no pleocytosis or antibodies in CSF), and none of 36 specimens from patients without Lyme borreliosis (no antibodies in serum or CSF). Overall, the real-time PCR assay enabled sensitive and specific detection of all B. burgdorferi sensu lato species tested. The PCR had a sensitivity of 50% in patients with neuroborreliosis. The main diagnostic role of the assay could be to confirm neuroborreliosis in patients for whom the diagnosis is doubtful.

Genetic diversity of Borrelia burgdorferi sensu stricto in Peromyscus leucopus, the primary reservoir of Lyme disease in a region of endemicity in southern Maryland

In the north central and northeastern United States, Borrelia burgdorferi sensu stricto, the etiologic agent of Lyme disease (LD), is maintained in an enzootic cycle between the vector, Ixodes scapularis, and the primary reservoir host, Peromyscus leucopus. Genetic diversity of the pathogen based on sequencing of two plasmid-located genes, those for outer surface protein A (ospA) and outer surface protein C (ospC), has been examined in both tick and human specimens at local, regional, and worldwide population scales. Additionally, previous studies have only been conducted with tick or human specimens at the local population level in areas with high LD transmission rates. This study examined the genetic diversity of circulating borreliae in the reservoir population from a large region of the western coastal plains of southern Maryland, where moderate numbers of human LD cases are reported. Six ospA mobility classes, including two that were not previously described, and eight ospC groups were found among the P. leucopus samples. Twenty-five percent of all specimens were infected with more than one ospA or ospC variant. The frequency distribution of variants was homogeneous, both locally and spatially. The spirochete diversity found in Maryland was not as high as that observed among northern tick populations, yet similar genotypes were observed in both populations. These results also show that mice are important for maintaining Borrelia variants, even rare variants, and that reservoir populations should therefore be considered when assessing the diversity of B. burgdorferi.

Comparative genome hybridization reveals substantial variation among clinical isolates of Borrelia burgdorferi sensu stricto with different pathogenic properties

Clinical and murine studies suggest that there is a differential pathogenicity of different genotypes of Borrelia burgdorferi, the spirochetal agent of Lyme disease. Comparative genome hybridization was used to explore the relationship between different genotypes. The chromosomes of all studied isolates were highly conserved (>93%) with respect to both sequence and gene order. Plasmid sequences were substantially more diverse. Plasmids lp54, cp26, and cp32 were present in all tested isolates, and their sequences and gene order were conserved. The majority of linear plasmids showed variation both in terms of presence among different isolates and in terms of sequence and gene order. The data strongly imply that all B. burgdorferi clinical isolates contain linear plasmids related to each other, but the structure of these replicons may vary substantially from isolate to isolate. These alterations include deletions and presumed rearrangements that are likely to result in unique plasmid elements in many isolates. There is a strong correlation between complete genome hybridization profiles and other typing methods, which, in turn, also correlate to differences in pathogenicity. Because there is substantially less variation in the chromosomal and circular plasmid portions of the genome, the major differences in open reading frame content and genomic diversity among isolates are linear plasmid driven.

Enhanced culture of Borrelia garinii and Borrelia afzelii strains on a solid BSK-based medium in anaerobic conditions

The growth of 29 human strains from the three main pathogenic species of Borrelia burgdorferi sensu lato on a solid BSK-based medium was compared in two culture atmospheres: 3% CO(2) air and anaerobiosis. All strains grew under anaerobic conditions, whereas only 13 strains were able to grow in aerobiosis with 3% CO(2) (P<0.001). In the latter condition, 75% of the B. burgdorferi sensu stricto strains grew versus 33% of the B. garinii and B. afzelii strains. These data suggest that, especially for B. garinii and B. afzelii species, anaerobic conditions enhance growth yield and speed of low-passage Borrelia strains.

Coinfections acquired from ixodes ticks

The pathogens that cause Lyme disease (LD), human anaplasmosis, and babesiosis can coexist in Ixodes ticks and cause human coinfections. Although the risk of human coinfection differs by geographic location, the true prevalence of coinfecting pathogens among Ixodes ticks remains largely unknown for the majority of geographic locations. The prevalence of dually infected Ixodes ticks appears highest among ticks from regions of North America and Europe where LD is endemic, with reported prevalences of < or =28%. In North America and Europe, the majority of tick-borne coinfections occur among humans with diagnosed LD. Humans coinfected with LD and babesiosis appear to have more intense, prolonged symptoms than those with LD alone. Coinfected persons can also manifest diverse, influenza-like symptoms, and abnormal laboratory test results are frequently observed. Coinfecting pathogens might alter the efficiency of transmission, cause cooperative or competitive pathogen interactions, and alter disease severity among hosts. No prospective studies to assess the immunologic effects of coinfection among humans have been conducted, but animal models demonstrate that certain coinfections can modulate the immune response. Clinicians should consider the likelihood of coinfection when pursuing laboratory testing or selecting therapy for patients with tick-borne illness.

A LightCycler TaqMan assay for detection of Borrelia burgdorferi sensu lato in clinical samples

Lyme disease (LD) is an infection caused by an ixodid tick-borne spirochete, Borrelia burgdorferi sensu lato. LD manifests itself as a multisystem inflammatory disease that affects the skin in its early localized stage and spreads to the joints, nervous system, heart, and, to a lesser extent, other organ systems in its later disseminated stages. If diagnosed and treated early with appropriate antibiotics, LD is almost always readily cured. Developing a highly sensitive and specific real-time polymerase chain reaction assay could be very useful in improving the diagnostic accuracy and decreasing turnaround time for results. We report the development of a LightCycler TaqMan assay targeting the OspA gene for clinical detection of B. burgdorferi sensu lato in various types of biologic samples. This assay was validated by testing a variety of clinical samples including cerebrospinal fluid, synovial fluid, skin biopsies, and blood and culture isolates from skin biopsies. The TaqMan testing results were 100% concordant with previously reported results. Reference strains representing isolates from other geographic regions were also successfully amplified. The developed assay is robust, is highly sensitive and specific for B. burgdorferi sensu lato, and is suitable for clinical detection of the bacterium in biologic samples.

Comparative genome analysis: selection pressure on the Borrelia vls cassettes is essential for infectivity

Background

At least three species of Borrelia burgdorferi sensu lato (Bbsl) cause tick-borne Lyme disease. Previous work including the genome analysis of B. burgdorferi B31 and B. garinii PBi suggested a highly variable plasmid part. The frequent occurrence of duplicated sequence stretches, the observed plasmid redundancy, as well as the mainly unknown function and variability of plasmid encoded genes rendered the relationships between plasmids within and between species largely unresolvable.

Results

To gain further insight into Borreliae genome properties we completed the plasmid sequences of B. garinii PBi, added the genome of a further species, B. afzelii PKo, to our analysis, and compared for both species the genomes of pathogenic and apathogenic strains.

The core of all Bbsl genomes consists of the chromosome and two plasmids collinear between all species. We also found additional groups of plasmids, which share large parts of their sequences. This makes it very likely that these plasmids are relatively stable and share common ancestors before the diversification of Borrelia species.

The analysis of the differences between B. garinii PBi and B. afzelii PKo genomes of low and high passages revealed that the loss of infectivity is accompanied in both species by a loss of similar genetic material. Whereas B. garinii PBi suffered only from the break-off of a plasmid end, B. afzelii PKo lost more material, probably an entire plasmid. In both cases the vls gene locus encoding for variable surface proteins is affected.

Conclusion

The complete genome sequences of a B. garinii and a B. afzelii strain facilitate further comparative studies within the genus Borrellia. Our study shows that loss of infectivity can be traced back to only one single event in B. garinii PBi: the loss of the vls cassettes possibly due to error prone gene conversion. Similar albeit extended losses in B. afzelii PKo support the hypothesis that infectivity of Borrelia species depends heavily on the evasion from the host response.

Comparison of five different immunoassays for the detection of Borrelia burgdorferi IgM and IgG antibodies

The performances of five commercially available enzyme immunoassays were compared for the detection of Borrelia burgdorferi IgM and IgG antibodies. Sensitivity was assessed with European serum samples collected from 45 patients with clinically defined Lyme disease in conjunction with a positive immunoblot (n = 44) or other serological test (n = 1). Sensitivities for the detection of IgM and IgG with each test were: Dako IgM 64%; Dako IgG 53%; Serion IgM 89%; and Serion IgG 88%. The Immunetics assay makes no distinction between IgM and IgG antibodies and had a sensitivity of 91%. Specificity was calculated by testing a control group comprising 40 patients with acute Epstein-Barr virus infection, cytomegalovirus infection, syphilis or rheumatoid factor positivity. The specificities achieved for each test were: Dako IgM 78%; Dako IgG 100%; Serion IgM 52%; Serion IgG 92%; and Immunetics 92%. The discriminatory power between control and patient samples appeared highest for the Immunetics assay. Between-run variation was comparable for the five tests and did not exceed 13%. When the Immunetics assay was used as an initial screening test, with low-titre positive results confirmed by an immunoblot, a sensitivity of 91% and a specificity of 100% were achieved. To attain maximal sensitivity, the Serion IgM and IgG tests were also performed on samples with negative Immunetics results. All positive Serion IgM and IgG results were also confirmed by immunoblot. In conclusion, the Immunetics assay, based on a synthetic C6 peptide, can be used reliably as an initial screening test for the serodiagnosis of Lyme disease.

REFRACTORINESS OF THE WESTERN FENCE LIZARD (SCELOPORUS OCCIDENTALIS) TO THE LYME DISEASE GROUP SPIROCHETE BORRELIA BISSETTII

The western fence lizard, Sceloporus occidentalis, is refractory to experimental infection with Borrelia burgdorferi sensu stricto, one of several Lyme disease spirochetes pathogenic for humans. Another member of the Lyme disease spirochete complex, Borrelia bissettii, is distributed widely throughout North America and a similar, if not identical, spirochete has been implicated as a human pathogen in southern Europe. To determine the susceptibility of S. occidentalis to B. bissettii, 6 naïve lizards were exposed to the feeding activities of Ixodes pacificus nymphs experimentally infected with this spirochete. None of the lizards developed spirochetemias detectable by polymerase chain reaction for up to 8 wk post-tick feeding, infected nymphs apparently lost their B. bissettii infections within 1-2 wk after engorgement, and xenodiagnostic L. pacificus larvae that co-fed alongside infected nymphs did not acquire and maintain spirochetes. In contrast, 3 of 4 naïve deer mice (Peromyscus maniculatus) exposed similarly to feeding by 1 or more B. bissettii-infected nymphs developed patent infections within 4 wk. These and previous findings suggest that the complement system of S. occidentalis typically destroys B. burgdorferi sensu lato spirochetes present in tissues of attached and feeding I. pacificus nymphs, thereby potentially reducing the probability of transmission of these bacteria to humans or other animals by the resultant adult ticks.

A single-run, real-time PCR for detection and identification of Borrelia burgdorferi sensu lato species, based on the hbb gene sequence

Lyme borreliosis is the most important vector-borne disease caused by spirochetes within the Borrelia burgdorferi sensu lato (B. burgdorferi sl) complex. There is strong evidence that different species of this group of genetically diverse spirochetes are involved in distinct clinical manifestations of the disease. In order to differentiate species within this bacterial complex, we developed a real-time-PCR protocol, which targets the hbb gene. We designed a fluorescein-labeled probe specific of a region of this gene harboring a polymorphism linked to species. An internally Red640 labeled primer allowed a fluorescence resonance energy transfer to occur. The sensitivity of this method was in the range of 10 bacteria per assay. After amplification, a melting curve was generated for genotyping. Analysis of these melting curves clearly allowed the distinction between the main European species of B. burgdorferi sl. One hundred seventy tick extracts were analysed by this hbb-based method and in parallel by amplification of the 5S-23S intergenic spacer and RFLP analyses. There was a good correlation between these two methods. We conclude that this hbb-based real-time-PCR is suitable for epidemiological studies on field-collected ticks, although rare mutations in the genomic sequence spanned by the probe could lead to misidentification.

A decrease in the immunoglobulin G antibody response against the VlsE protein of Borrelia burgdorferi sensu lato correlates with the resolution of clinical signs in antibiotic-treated patients with early Lyme disease

The purpose of this study was to evaluate the diagnostic performance of the LIAISON Borrelia Screen (Diasorin, Saluggia, Italy), a new automated immunoassay based on the chemiluminescent technology (chemiluminescence immunoassay). To assess whether a decrease in a negative value in the anti-VlsE immunoglobulin G (IgG) antibody titer was correlated with a positive response to treatment, a group of serially collected serum samples from 67 patients with culture-confirmed erythema migrans was retrospectively studied. All the patients had been treated with antibiotics and were free of disease within 3 to 6 months of follow-up. All the 15 patients who were found to be IgG positive at the time of enrollment and who were bled at least four times during the follow-up became IgG seronegative at 2 to 6 months posttreatment. These results indicate that a decline in the anti-VlsE antibody titer coincides with effective antimicrobial therapy in patients with early localized Lyme disease.

Sylvatic maintenance of Borrelia burgdorferi (Spirochaetales) in Northern California: untangling the web of transmission

Lyme borreliosis is associated with several genospecies of Borrelia burgdorferi sensu lato (s.l.) (Spirochaetales), but human disease has been associated only with Borrelia burgdorferi sensu stricto (s.s.) Johnson, Schmid, Hyde, Steigerwalt & Brenner in the western United States. Restriction fragment length polymorphism (RFLP) analysis of rrf-rrl amplicons from 124 tick and mammalian isolates from various habitats yielded 13 RFLP patterns. Of these patterns, six were patterns previously associated either with Borrelia bissettii Postic, Marti Ras, Lane, Hendson & Baranton or Borrelia burgdorferi s.s., and the remaining seven patterns belonged to diverse and previously uncharacterized Borrelia spp. Uncharacterized Borrelia spp. were cultured most frequently from Ixodes spinipalpis Hadwen & Nuttall and California kangaroo rats, Dipodomys californicus Merriam, inhabiting grasslands, and B. bissettii from I. spinipalpis and dusky-footed woodrats, Neotoma fuscipes Baird, associated with oak woodlands or chaparral. B. burgdorferi s.s. typically was isolated from host-seeking Ixodes pacificus Cooley & Kohls collected in dense oak woodlands, woodland-grass, or redwood forests. Although some isolates of B. burgdorferi s.s. were cultured from woodrats, there was no clear association of this human pathogen with any vertebrate host. These findings, along with recent evidence indicating that the western gray squirrel, Sciurus griseus Ord, may be an important reservoir of B. burgdorferi s.s. in Californian oak woodlands, suggest that our earlier hypothesis implicating an enzootic cycle involving woodrats and I. spinipalpis is insufficient to account for observed patterns of infection in nature.

Molecular fingerprinting methods for the discrimination between C. albicans and C. dubliniensis

Opportunistic fungal pathogens are becoming increasingly important causes of both community-acquired and nosocomial infections. The most important fungal pathogens are yeast species belonging to the genus Candida. These species show differences in levels of resistance to antifungal agents and mortality. Consequently, it is important to correctly identify the causative organism to the species level. Identification of Candida dubliniensis in particular remains problematic because of the high degree of phenotypic similarity between this species and Candida albicans. However, as the differences between both are most pronounced at the genetic level, several studies have been conducted in order to provide a specific and rapid identification fingerprinting molecular test. In most candidal infectious, no single DNA fingerprinting technique has evolved as a dominant method, and each method has its advantages, disadvantages and limitations. Moreover, the current challenge of these techniques is to compile standardized patterns in a database for interlaboratory use and future reference. This review provides an overview of most common molecular fingerprinting techniques currently available for discrimination of C. albicans and C. dubliniensis.

Differentiation ofBorrelia burgdorferi sensu lato species by temperature gradient gel electrophoresis

Borrelia burgdorferi sensu lato is a multispecies complex of pathogenic spirochetes, causing Lyme borreliosis. Due to clinical, epidemiological, and taxonomical implications, there is a need for identification of isolated Borrelia strains. In the present study, we have optimized TGGE for B. burgdorferi sensu lato species differentiation and the results were compared with two reference methods, namely PFGE and restriction of 5S-23S intergenic space region PCR product. A differentiation of B. garinii, B. afzelii, and B. burgdorferi senso stricto species with TGGE was possible and intraspecies variation was detected. Results compared between TGGE, PFGE, and restriction of 5S-23S intergenic space region PCR product showed no difference in specificity of species identification.

Prevalence of Borrelia burgdorferi s.l. OspA types in Ixodes ricinus ticks from selected localities in Slovakia and Poland

In this study, 746 questing Ixodes (I.) ricinus ticks from eastern Slovakia and 187 ticks from southern Poland were investigated for infection with Borrelia (B.) burgdorferi sensu lato and different outer surface protein A (OspA) types by an improved restriction fragment length polymorphism (RFLP) analysis of the ospA gene. The method enables differentiation of both single and multiple infections with B. burgdorferi s.s. (OspA type 1), B. afzelii (OspA type 2), B. garinii (OspA types 3-8), B. valaisiana (subgroups I and II), B. lusitaniae, B. bissettii, and the recently described genospecies A14S. Broad heterogeneity in B. burgdorferi s.l. was found including all species and subtypes except for B. lusitaniae, B. bissettii, and genospecies A14S. Regional prevalence of B. burgdorferi s.l. varied between 8% and 22.5%. The most frequent species were B. garinii (45.4%) and, notably, B. burgdorferi s.s. (31.3%). I. ricinus nymphs harbored almost exclusively B. burgdorferi s.s. and B. garinii OspA type 4, while in adults a broad variety of B. burgdorferi s.l. types was found. Mixed infections were significantly more often in nymphs than in adult ticks. In all mixed infected nymphs, B. burgdorferi s.s. with OspA type 4 was present. These data strongly suggest that B. burgdorferi s.s. and B. garinii OspA type 4 are maintained in these areas by specific transmission cycles involving a so far undetermined vertebrate host which is frequently fed on by I. ricinus larvae. This improved method provides a reliable tool for epidemiological studies on the heterogeneity of B. burgdorferi species and OspA types, an important prerequisite for improved local risk assessment and for test- and vaccine development for Europe.

Comparison of isolation rate of Borrelia burgdorferi sensu lato in MKP and BSK-II medium

Different media have been utilized for borrelial cultivation. The aim of the present study was to evaluate the isolation rate of Borrelia burgdorferi sensu lato from two commonly used media, i.e. modified Kelly-Pettenkofer (MKP) and Barbour-Stoenner-Kelly II (BSK-II) medium, and to compare the isolated strains with regard to their phenotypic and genotypic characteristics. Skin biopsy specimens of 2 x 2 x 4 mm were taken from the peripheral site of human solitary erythema lesions and were divided in two pieces, one of which was inoculated into MKP and the other one into BSK-II medium. Species analysis of the obtained strains was performed and their plasmid and protein profiles were determined. Borrelia strains were isolated from 48/96 patients (50%) with erythema migrans. We obtained in 26/48 patients (54%) from MKP as well as from BSK-II, in 11 patients (23%) only from MKP, and in another 11 (23%) only from BSK-II medium a positive result. B. afzelii was isolated from 43 patients (23 were positive in both media, nine in MKP only and 11 in BSK-II medium only), while B. garinii was isolated from five patients (in three from both media, in two from MKP only). All strains of the obtained strain pairs were identical according to species and the type within the species. Plasmid profiles were identical in 17/21 B. afzelii strain pairs (81%) and in 1/3 B. garinii strain pairs; in 6/24 strain pairs, distinctions in the number of plasmids or in their molecular mass were present. Differences in the protein profile were found in 7/24 strain pairs (29%). The distinctions were uniform and were limited to the expression of OspC. In conclusion, our study showed comparable Borrelia isolation rates from MKP and BSK-II medium. The results of the present study indicate that human patients with Lyme borreliosis may simultaneously harbor heterogeneous B. burgdorferi s.l. strains.

Structure-function mapping of BbCRASP-1, the key complement factor H and FHL-1 binding protein of Borrelia burgdorferi

Borrelia burgdorferi, a spirochaete transmitted to human hosts during feeding of infected Ixodes ticks, is the causative agent of Lyme disease, the most frequent vector-borne disease in Eurasia and North America. Sporadically Lyme disease develops into a chronic, multisystemic disorder. Serum-resistant B. burgdorferi strains bind complement factor H (FH) and FH-like protein 1 (FHL-1) on the spirochaete surface. This binding is dependent on the expression of proteins termed complement-regulator acquiring surface proteins (CRASPs). The atomic structure of BbCRASP-1, the key FHL-1/FH-binding protein of B. burgdorferi, has recently been determined. Our analysis indicates that its protein topology apparently evolved to provide a high affinity interaction site for FH/FHL-1 and leads to an atomic-level hypothesis for the functioning of BbCRASP-1. This work demonstrates that pathogens interact with complement regulators in ways that are distinct from the mechanisms used by the host and are thus obvious targets for drug design.

Typing African relapsing fever spirochetes

Sequencing distinguished relapsing fever from other borrelial species but not B. duttonii from B. recurrentis.

Relapsing fever Borrelia spp. challenge microbiologic typing because they possess segmented genomes that maintain essential genes on large linear plasmids. Antigenic variation further complicates typing. Intergenic spacer (IGS, between 16S–23S genes) heterogeneity provides resolution among Lyme disease–associated and some relapsing fever spirochetes. We used an IGS fragment for typing East African relapsing fever Borrelia spp. Borrelia recurrentis and their louse vectors showed 2 sequence types, while 4 B. duttonii and their tick vectors had 4 types. IGS typing was unable to discriminate between the tick- and louseborne forms of disease. B. crocidurae, also present in Africa, was clearly resolved from the B. recurrentis/B. duttonii complex. IGS analysis of ticks showed relapsing fever Borrelia spp. and a unique clade, distant from those associated with relapsing fever, possibly equivalent to a novel species in ticks from this region. Clinical significance of this spirochete is undetermined.

Fibronectin binding protein BBK32 of the Lyme disease spirochete promotes bacterial attachment to glycosaminoglycans

Borrelia burgdorferi, the agent of Lyme disease, causes a multisystemic illness that can affect the skin, heart, joints, and nervous system and is capable of attachment to diverse cell types. Among the host components recognized by this spirochete are fibronectin and glycosaminoglycans (GAGs). Three surface-localized GAG-binding bacterial ligands, Bgp, DbpA, and DbpB, have been previously identified, but recent studies suggested that at least one additional GAG-binding ligand is expressed on the spirochetal surface when the spirochete is adapted to the mammalian host environment. BBK32 is a surface lipoprotein that is produced during infection and that has been shown to bind to fibronectin. In this study, we show that, when BBK32 was produced from a shuttle vector in an otherwise nonadherent high-passage B. burgdorferi strain, the protein localized on the bacterial surface and conferred attachment to fibronectin and to mammalian cell monolayers. In addition, the high-passage strain producing BBK32 bound to purified preparations of the GAGs dermatan sulfate and heparin, as well as to these GAGs on the surfaces of cultured mammalian cells. Recombinant BBK32 recognized purified heparin, indicating that the bacterial attachment to GAGs was due to direct binding by BBK32. This GAG-binding activity of BBK32 is apparently independent of fibronectin recognition, because exogenous heparin had no effect on BBK32-mediated bacterial binding to fibronectin.

Tick-borne encephalopathies : epidemiology, diagnosis, treatment and prevention

Tick-borne encephalopathies constitute a broad range of infectious diseases affecting the brain and other parts of the CNS. The causative agents are both viral and bacterial. This review focuses on the current most important tick-borne human diseases: tick-borne encephalitis (TBE; including Powassan encephalitis) and Lyme borreliosis. Rocky Mountain spotted fever (RMSF) and Colorado tick fever (CTF), less common tick-borne diseases associated with encephalopathy, are also discussed. TBE is the most important flaviviral infection of the CNS in Europe and Russia, with 10 000-12 000 people diagnosed annually. The lethality of TBE in Europe is 0.5% and a post-encephalitic syndrome is seen in over 40% of affected patients, often producing a pronounced impairment in quality of life. There is no specific treatment for TBE. Two vaccines are available to prevent infection. Although these have a good protection rate and good efficacy, there are few data on long-term immunity. Lyme borreliosis is the most prevalent tick-borne disease in Europe and North America, with >50 000 cases annually. Localised early disease can be treated with oral phenoxymethylpenicillin (penicillin V), doxycycline or amoxicillin. The later manifestations of meningitis, arthritis or acrodermatitis can be treated with oral doxycycline, oral amoxicillin or intravenous ceftriaxone; intravenous benzylpenicillin (penicillin G) or cefotaxime can be used as alternatives. The current use of vaccines against Lyme borreliosis in North America is under discussion, as the LYMErix vaccine has been withdrawn from the market because of possible adverse effects, for example, arthritis. RMSF and CTF appear only in North America. RMSF is an important rickettsial disease and is effectively treated with doxycycline. There is no treatment or preventative measure available for CTF.

Complement escape of human pathogenic bacteria by acquisition of complement regulators

Pathogenic micro-organisms employ a broad range of strategies to survive in and to persistently infect the human host. Far from being completely understood by which highly sophisticated means invading pathogens overcome the host's destructive immune defence, there is a growing body of evidence on particular mechanisms which play a pivotal role for immune evasion. This review focuses on evasion of medically and scientifically important bacteria by acquisition of host derived fluid-phase complement regulatory proteins, in particular factor H, FHL-1, and C4b binding protein. Expression of microbial surface molecules binding to human complement regulators and thus fixing them in a functionally active state allows pathogens to inhibit and finely regulate complement activation directly on their surface. Further studies on the utilization of host complement regulatory proteins will likely have a marked impact on a more efficient and specific clinical treatment.

Comparative transcriptional profiling of Borrelia burgdorferi clinical isolates differing in capacities for hematogenous dissemination

Borrelia burgdorferi, the etiologic agent of Lyme disease, is genetically heterogeneous. Previous studies have shown a significant association between the frequency of hematogenous dissemination in Lyme disease patients and the genotype of the infecting B. burgdorferi strain. Comparative transcriptional profiling of two representative clinical isolates with distinct genotypes (BL206 and B356) was undertaken. A total of 78 open reading frames (ORFs) had expression levels that differed significantly between the two isolates. A number of genes with potential involvement in nutrient uptake (BB0603, BBA74, BB0329, BB0330, and BBB29) have significantly higher expression levels in isolate B356. Moreover, nearly 25% of the differentially expressed genes are predicted to be localized on the cell surface, implying that these two isolates have cell surface properties that differ considerably. One of these genes, BBA74, encodes a protein of 257 amino acid residues that has been shown to possess porin activity. BBA74 transcript level was >20-fold higher in B356 than in BL206, and strain B356 contained three- to fivefold more BBA74 protein. BBA74 was disrupted by the insertion of a kanamycin resistance cassette into the coding region. The growth rates of both wild-type and mutant strains were essentially identical, and cultures reached the same final cell densities. However, the mutant strains consistently showed prolonged lags of 2 to 5 days prior to the induction of log-phase growth compared to wild-type strains. It is tempting to speculate that the absence of BBA74 interferes with the enhanced nutrient uptake that may be required for the entry of cells into log-phase growth. These studies demonstrate the value of comparative transcriptional profiling for identifying differences in the transcriptomes of B. burgdorferi clinical isolates that may provide clues to pathogenesis. The 78 ORFs identified here are a good starting point for the investigation of factors involved in the hematogenous dissemination of B. burgdorferi.

Improved method of detection and molecular typing of Borrelia burgdorferi sensu lato in clinical samples by polymerase chain reaction without DNA purification

A simple assay by polymerase chain reaction was used for the of detection of Borrelia burgdorferi, causative agent of Lyme borreliosis (LB). It involves no DNA purification and is based on the amplification of a specific region of ospA gene of B. burgdorferi, followed by direct detection of the PCR product with SYBR Green I by agarose gel electrophoresis. The method was used to analyze samples from patients with LB diagnosis, with presumable infection with the LB spirochete, those with unclear clinical symptoms and after the course of an antibiotic treatment. Spirochetal DNA was detected by PCR even in contaminated samples in which B. burgdorferi was overgrown by fungi and other bacteria. Spirochetal DNA was detected and borrelia species was identified in cerebrospinal fluid of two patients hospitalized with the diagnosis "fever of unknown origin". Western blot and ELISA were negative in both cases. Total analysis of 94 samples from the hospital in Ceské Budejovice (South Bohemia, Czechia) showed infection with B. burgdorferi sensu stricto in 11% and B. garinii in 15% of cases. The highest prevalence was found for B. afzelii (43%). Co-infection was confirmed in 24 % of the analyzed symplex; 7% of samples that were B. burgdorferi sensu lato positive gave no results in DNA amplification with B. burgdorferi sensu stricto-, B. garinii- and B. afzelii-specific primers. The proposed reliable, rapid, unexpensive and specific technique could form the basis of laboratory tests for routine detection and identification of Lyme-disease spirochete in different samples.

Complement Regulator-Acquiring Surface Protein 1 Imparts Resistance to Human Serum inBorrelia burgdorferi

Factor H and factor H-like protein 1 (FH/FHL-1) are soluble serum proteins that negatively regulate the alternative pathway of complement. It is now well recognized that many pathogenic bacteria, including Borrelia burgdorferi, bind FH/FHL-1 on their cell surface to evade complement-mediated destruction during infection. Recently, it was suggested that B. burgdorferi open reading frame bbA68, known as complement regulator-acquiring surface protein 1 (CRASP-1), encodes the major FH/FHL-1-binding protein of B. burgdorferi. However, because several other proteins have been identified on the surface of B. burgdorferi that also can bind FH/FHL-1, it is presently unclear what role CRASP-1 plays in serum resistance. To examine the contribution of CRASP-1 in serum resistance, we generated a B. burgdorferi mutant that does not express CRASP-1. The B. burgdorferi CRASP-1 mutant, designated B31cF-CRASP-1, was found to be as susceptible to human serum as a wild-type strain of Borrelia garinii 50 known to be sensitive to human serum. To further examine the role of CRASP-1 in serum resistance, we also created a shuttle vector that expresses CRASP-1 from the native B. burgdorferi gene, which was designated pKFSS-1::CRASP-1. When the pKFSS-1::CRASP-1 construct was transformed into the B. burgdorferi B31cF-CRASP-1 mutant, wild-type levels of serum resistance were restored. Additionally, when pKFSS-1::CRASP-1 was transformed into the serum-sensitive B. garinii 50 isolate, human serum resistance was imparted on this strain to a level indistinguishable from wild-type B. burgdorferi. The combined data led us to conclude that CRASP-1 expression is necessary for B. burgdorferi to resist killing by human serum.

Sensitivity of Borrelia genospecies to serum complement from different animals and human: a host-pathogen relationship

Different Borrelia species and serotypes were tested for their sensitivity to serum complement from various animals and human. Complement-mediated Borrelia killing in cattle, European bison and deer was higher irrespective of the Borrelia species whereas in other animals and human it was intermediate and Borrelia species-dependent. Activation of the alternative complement pathway by particular Borrelia strain was in correlation with its sensitivity or resistance. These results support the incompetent reservoir nature of cattle, European bison, red, roe and fallow deer, at the same time present the probable reservoir nature of mouflon, dog, wolf, cat and lynx. In short, this study reviews Borrelia-host relationship and its relevance in reservoir competence nature of animals.

Phylogenetic analysis of the spirochetes Borrelia parkeri and Borrelia turicatae and the potential for tick-borne relapsing fever in Florida

Isolates of Borrelia turicatae, Borrelia parkeri, and the Florida canine borrelia (FCB) were examined to further phylogenetically characterize the identities of these spirochetes in the United States. DNA sequences of four chromosomal loci (the 16S rRNA gene, flaB, gyrB, and glpQ) were determined for eight isolates of B. turicatae and six isolates of B. parkeri, which grouped the spirochetes into two distinct but closely related taxa (>98% sequence identity) separate from Borrelia hermsii. The FCB was clearly separated with the group identified as B. turicatae, confirming this bacterium as a relapsing fever spirochete. Therefore, the potential for tick-borne relapsing fever in humans and other animals exists in Florida and future efforts are needed to determine the enzootic hosts and distribution of this spirochete in the southeastern United States. Analysis of plasmids demonstrated both linear and circular forms in B. turicatae but only linear plasmids in B. parkeri, which should be of interest to investigators concerned with plasmid diversity and evolution within this group of spirochetes.

The nervous system as ectopic germinal center: CXCL13 and IgG in lyme neuroborreliosis

Lyme neuroborreliosis (LNB) is a chronic infection in which B-cell activation, plasma cell infiltration, and enhanced Ig production in infected tissue are prominent feature. However, little is known about how B cells and plasma cells invade and persist in target organs. To assess this issue, we developed real-time PCR measurements of IgG and CXCL13 production. We used these RNA assays and specific enzyme-linked immunosorbent assays for protein and demonstrated that human peripheral blood mononuclear cells (PBMCs), stimulated by Borrelia burgdorferi sonicate, produced CXCL13 and IgG. Magnetic separation of PBMC populations and flow cytometry showed that CXCL13 is produced by dendritic cells. We then measure the expression of CXCL13 and IgG in tissues and correlated the expression of these host genes with spirochetal load. We also measured expression of dbpA and BBK32, two spirochetal genes important in chronic infection. There was a strong correlation between host immune response gene expression (CXCL13 and IgG) and spirochetal load. Immunohistochemistry of infected nonhuman primates tissue confirmed that CXCL13 is expressed in the nervous system. We conclude that persistent production of CXCL13 and IgG within infected tissue, two characteristics of ectopic germinal centers, are definitive features of LNB.

Comparison of Borrelia burgdorferi sensu lato strains isolated from specimens obtained simultaneously from two different sites of infection in individual patients

The aim of the present study was to analyze and compare Borrelia strains isolated from two different specimens obtained simultaneously from individual patients with Lyme borreliosis. Fifty such patients and 50 corresponding pairs of Borrelia isolates (100 low-propagated strains) were subjected to genotypic and phenotypic analysis, including pulsed-field gel electrophoresis for species identification and plasmid profile determination and protein profile electrophoresis for the assessment of the presence and molecular masses of separated proteins. The strains were isolated from two distinct skin lesions (12 patients), skin and blood (28 patients), skin and cerebrospinal fluid (8 patients), and blood and cerebrospinal fluid (2 patients). Out of 100 isolates, 63 were typed as B. afzelii and 37 as B. garinii. From each individual specimen only a single Borrelia species was cultured. Comparison of 50 Borrelia strain pairs isolated from two different specimens of an individual patient revealed that 12/50 (24%) patients were simultaneously infected with two different Borrelia strains; in 3/50 (6%) patients strains differed at the species level, in 4 out of the remaining 47 (9%) patients a strain difference in plasmid profile was established, while 5 out of the remaining 43 (11%) patient strain pairs differed in regard to the protein profiles of the two concurrently isolated strains. The results of the present study indicate that human patients with Lyme borreliosis may simultaneously harbor different B. burgdorferi sensu lato strains.