Improving the yield of blood cultures for patients with early Lyme disease

The major epidemiologic, microbiologic, immunologic, and clinical aspects of Lyme disease that form the basis for a newly developed vaccine that may become available soon for human use

Working together, two major pharmaceutical companies have developed a Lyme disease vaccine consisting of recombinant-derived outer surface protein A (OspA) of the etiologic agent Borrelia burgdorferi. Multiple clinical trials have shown the vaccine to have good safety and efficacy results, and it is hoped that it would become available for human use at least by the year 2025 after receiving approval from the U.S. Food and Drug Administration. There are still challenges left to ensure that the vaccine has, at most, minimal side effects. Also, because the previously developed Lyme disease vaccine was discontinued in 2002 after four years of distribution, due in part, for frivolous reasons having little or no scientific basis, that even led to legal entanglements involving the vaccine manufacturer and some of the medical personnel overseeing the clinical trials, there will be concerns that this newly developed one could be subject again to some of the same unnecessary scrutiny rendering its implementation suboptimal. Initially this review will focus on the key epidemiological, microbiologic, immunologic and clinical aspects of Lyme disease that provide the foundation for developing this type of vaccine that could have a serious impact on the prevalence of this and even certain other tick-transmitted infections.

The Platelet Fraction Is a Novel Reservoir to Detect Lyme Borrelia in Blood

Simple Summary

To diagnose Lyme disease, a patient’s blood is tested for antibodies that develop as part of the immune response. This can lead to cases being missed or inadequately treated. An ideal test would directly detect the Lyme disease bacteria, Borrelia, to provide better clinical guidance. In this study, we aimed to improve the methods currently used to find Borrelia in human blood, and identified two opportunities for optimization. We demonstrate that the container most commonly used to collect blood (EDTA) decreases Borrelia’s ability to grow, and we identify a superior alternative (citrate). Additionally, using experimentally infected blood, we show that Borrelia is highly concentrated in the platelet fraction, making it an ideal candidate for direct detection. These results lay the foundation for diagnostic test development, which could improve patient outcomes in Lyme disease.

Abstract

Serological diagnosis of Lyme disease suffers from considerable limitations. Yet, the technique cannot currently be replaced by direct detection methods, such as bacterial culture or molecular analysis, due to their inadequate sensitivity. The low bacterial burden in vasculature and lack of consensus around blood-based isolation of the causative pathogen, Borrelia burgdorferi, are central to this challenge. We therefore addressed methodological optimization of Borrelia recovery from blood, first by analyzing existing protocols, and then by using experimentally infected human blood to identify the processing conditions and fractions that increase Borrelia yield. In this proof-of-concept study, we now report two opportunities to improve recovery and detection of Borrelia from clinical samples. To enhance pathogen viability and cultivability during whole blood collection, citrate anticoagulant is superior to more commonly used EDTA. Despite the widespread reliance on serum and plasma as analytes, we found that the platelet fraction of blood concentrates Borrelia, providing an enriched resource for direct pathogen detection by microscopy, laboratory culture, Western blot, and PCR. The potential for platelets to serve as a reservoir for Borrelia and its diagnostic targets may transform direct clinical detection of this pathogen.

Measurement of Organ-Specific and Acute-Phase Blood Protein Levels in Early Lyme Disease

Lyme disease results from infection of humans with the spirochete Borrelia burgdorferi. The first and most common clinical manifestation is the circular, inflamed skin lesion referred to as erythema migrans; later manifestations result from infections of other body sites. Laboratory diagnosis of Lyme disease can be challenging in patients with erythema migrans because of the time delay in the development of specific diagnostic antibodies against Borrelia. Reliable blood biomarkers for the early diagnosis of Lyme disease in patients with erythema migrans are needed. Here, we performed selected reaction monitoring, a targeted mass spectrometry-based approach, to measure selected proteins that (1) are known to be predominantly expressed in one organ (i.e., organ-specific blood proteins) and whose blood concentrations may change as a result of Lyme disease, or (2) are involved in acute immune responses. In a longitudinal cohort of 40 Lyme disease patients and 20 healthy controls, we identified 10 proteins with significantly altered serum levels in patients at the time of diagnosis, and we also developed a 10-protein panel identified through multivariate analysis. In an independent cohort of patients with erythema migrans, six of these proteins, APOA4, C9, CRP, CST6, PGLYRP2, and S100A9, were confirmed to show significantly altered serum levels in patients at time of presentation. Nine of the 10 proteins from the multivariate panel were also verified in the second cohort. These proteins, primarily innate immune response proteins or proteins specific to liver, skin, or white blood cells, may serve as candidate blood biomarkers requiring further validation to aid in the laboratory diagnosis of early Lyme disease.

Efficacy of a 14-day course of amoxicillin for patients with erythema migrans

Although a 14-day treatment course with amoxicillin is in wide clinical usage to treat early Lyme disease, only a few published studies exist to validate its efficacy and safety, with none in the United States. In this study, we reviewed the records of 24 prospectively followed adult patients with erythema migrans who were prescribed a 14-day course of amoxicillin, 500 mg 3 times daily. Treatment with amoxicillin was well tolerated and uniformly successful in resolving the erythema migrans skin lesion and in preventing the development of an objective neurologic, cardiac, or rheumatologic manifestation. Although the study was relatively small and only involved a single center, the findings provide additional evidence that a 14-day course of 500 mg amoxicillin given 3 times per day is highly effective therapy for patients with early Lyme disease.

The Accuracy of Diagnostic Tests for Lyme Disease in Humans, A Systematic Review and Meta-Analysis of North American Research

There has been an increasing incidence of Lyme disease (LD) in Canada and the United States corresponding to the expanding range of the Ixodes tick vector and Lyme disease agent (Borrelia burgdorferi sensu stricto). There are many diagnostic tests for LD available in North America, all of which have some performance issues, and physicians are concerned about the appropriate use and interpretation of these tests. The objective of this systematic review is to summarize the North American evidence on the accuracy of diagnostic tests and test regimes at various stages of LD. Included in the review are 48 studies on diagnostic tests used in North America published since 1995. Thirteen studies examined a two-tier serological test protocol vs. clinical diagnosis, 24 studies examined single assays vs. clinical diagnosis, 9 studies examined single immunoblot vs. clinical diagnosis, 7 studies compared culture or PCR direct detection methods vs. clinical diagnosis, 22 studies compared two or more tests with each other and 8 studies compared a two-tiered serological test protocol to another test. Recent studies examining the sensitivity and specificity of various test protocols noted that the Immunetics® C6 B. burgdorferi ELISA™ and the two tier approach have superior specificity compared to proposed replacements, and the CDC recommended western blot algorithm has equivalent or superior specificity over other proposed test algorithms. There is a dramatic increase in test sensitivity with progression of B. burgdorferi infection from early to late LD. Direct detection methods, culture and PCR of tissue or blood samples were not as sensitive or timely compared to serological testing. It was also noted that there are a large number of both commercial (n = 42) and in-house developed tests used by private laboratories which have not been evaluated in the primary literature.

Lyme Disease Diagnosis: Serology

Serology is the mainstay of confirmation of Lyme borreliosis; direct detection has limited application. Because standardized 2-tier testing (STTT) has been commonly used since the mid 1990s, standardization and performance have improved. STTT detection of early, localized infection is poor; that of late disease is good. The best indicator of stage 1 infection, erythema migrans, is presented in the majority of US cases and should prompt treatment without testing. Clinical and epidemiologic correlates should be carefully assessed before ordering STTT. STTT has great value in confirming extracutaneous infection. Recent developments promise to improve performance, particularly in early disease detection.

Comparison of isolation rate of Borrelia burgdorferi sensu lato in two different culture media, MKP and BSK-H

The aim of the study was to evaluate two culture media for Borrelia burgdorferi sensu lato isolation from a 5 × 2 × 2 mm skin biopsy that was dissected into two pieces and inoculated into modified Kelly-Pettenkofer (MKP) and Barbour-Stoenner-Kelly-H (BSK-H) medium. Samples were incubated at 33°C for up to 9 weeks. Borrelia species was determined by MluI-restriction of whole genome or by MseI-restriction of PCR product. We determined the proportion of isolation rate, 'slow-growers', contaminated specimens and Borrelia species in the two media. In each of the two media 235 skin specimens were cultivated. We found 90/470 (19.1%) contaminated cultures (BSK-H 67/235, 28.5%; MKP 23/235, 9.8%; p <0.0001). Borrelia growth was ascertained in 59/235 (25.1%) BSK-H and 102/235 (43.4%) MKP cultures (p <0.0001); the corresponding values for non-contaminated cultures were 59/168 (35.1%) and 102/212 (48.1%); (p 0.003). Fourteen specimens were positive only in BSK-H, 57 solely in MKP, and 43 in both culture media. Slow growth was present in 8/59 (13.6%) BSK-H and in 4/98 (4.1%) MKP positive cultures (p 0.019). Borrelia afzelii was identified in 44/51 (86.3%) BSK-H and in 88/98 (89.8%) MKP culture-positive samples; the corresponding findings for Boreelia garinii and B. burgdorferi sensu stricto were 6/51 (11.8%) and 9/98 (9.2%), and 1/51 (1.9%) and 1/98 (1.0%), for BSK-H and MKP, respectively. Comparison of MKP and BSK-H medium for Borrelia culturing from skin specimens of European patients with erythema migrans revealed the advantage of MKP over BSK-H.

[Role of biological assays in the diagnosis of Lyme borreliosis presentations. What are the techniques and which are currently available?]

The biological diagnosis of Borrelia burgdorferi sensu lato infection is usually made by antibody detection in patient sera. Thus, serological testing (Elisa, immunoblotting) is essential for a biological diagnosis. Specific antibody detection is usually done in serum and CSF of patients suspected of Lyme borreliosis. Laboratories must follow European recommendations to validate these assays in routine practice. Antibody detection lacks sensitivity in the early cutaneous phase of the infection. Therefore, serological testing is not recommended for the diagnosis of erythema migrans. The interpretation of serology must take into account the variability of Elisa sensitivity and specificity and the lack of standardization for Western-blotting in Europe. Besides these indirect diagnosis techniques, there is also direct detection of spirochetes by culture or by in vitro DNA amplification but these require adequate samples. These molecular tests must not be performed routinely, but only for specific clinical situations and in specialized laboratories only.

Hematogenous dissemination in early Lyme disease

Hematogenous dissemination has long been considered an important pathogenetic event in Lyme borreliosis but has been hard to document and characterize due to insensitive blood culture methods. In a series of recent investigations involving adult patients from the United States with erythema migrans, it was concluded that plasma was a better source of culture material than serum or whole blood, and yield correlated directly with the volume of material cultured. The rate of recovery of Borrelia burgdorferi from 9 mL of plasma exceeded 40%. Both the genotype of the strain of B. burgdorferi introduced by the tick and host factors, such as having a first episode of Lyme borreliosis and being more than 55 years of age, appear to affect the risk of hematogenous dissemination. Although the majority of spirochetemic patients are symptomatic, spirochetemia can be a subclinical event. In summary, hematogenous dissemination is a common and important feature of early Lyme borreliosis in the United States. The high rate, early onset and prolonged duration of risk of spirochetemia probably explain why untreated patients with erythema migrans may develop objective clinical manifestations at a distant anatomic site.

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.

Co-evolution of the outer surface protein C gene (ospC) and intraspecific lineages of Borrelia burgdorferi sensu stricto in the northeastern United States

Clinical and tick isolates of Borrelia burgdorferi sensu stricto, the bacterial agent of Lyme disease, from the northeastern United States were sequenced at 12 loci located on the main chromosome and 7 plasmids (lp54, cp26, cp9, lp17, lp25, lp28-2, and lp38). The outer surface protein C gene (ospC) showed the highest number (12) of major alleles (defined as alleles differing by 5% or more in nucleotide sequence) while other ORFs had only two to four major alleles. A non-recombining chromosomal marker, the rrs-rrlA ribosomal RNA spacer, was used to infer the intraspecific phylogeny among these B. burgdorferi isolates. We were thus able to analyze the multilocus genotypes in the context of a B. burgdorferi intraspecific phylogeny. Except for ospC, sequence variations at plasmid-borne loci showed broad inconsistency with the intraspecific phylogeny, supporting DNA exchanges mediated by plasmid transfers. The multilocus linkage frequently observed in B. burgdorferi populations is due more likely to a "founder effect" than to a lack of recombination. The exceptional phylogenetic consistency of ospC, in conjunction with its selectively maintained high intraspecific diversity, suggested a dominant role ospC plays in the initiation and maintenance of adaptive differentiation in B. burgdorferi.

Immunophenotypic patterns of T-cell activation in neuroinflammatory diseases

OBJECTIVES

We aimed to gain insights into the pathogen-specific differences in early adaptive immune responses following central nervous system infections with Borrelia burgdorferi and viral pathogens by studying the immunophenotypic patterns of T-cell activation. Moreover, we wished to determine whether the expression of T-cell activation markers reflects disease activity in multiple sclerosis (MS).

METHODS

Proportions of cerebrospinal fluid T-cells expressing the markers HLA-DR, CD25 and CD38 were determined in patients with MS (n = 40), acute viral meningomyeloradiculoneuritis (VID, n = 26), early neuroborreliosis (NB, n = 23) and non-inflammatory neurologic diseases (n = 51) by using flow cytometry. In relapsing-remitting MS, disease activity was assessed by clinical examination and magnetic resonance imaging.

RESULTS

For each of the surface markers that were examined, significant differences in T cell proportions were found between patient groups. The proportion of HLA-DR+ T cells was higher and that of CD25+ T cells lower in NB compared with VID. These differences were attributable only to the early phase of the disease (< or = 6 days after symptom onset). Among MS patients, there was a trend for higher proportions of T cells expressing activation markers in patients with gadolinium-enhancing lesions.

CONCLUSIONS

The decreased CD25 expression in NB may reflect immunomodulatory effects of B. burgdorferi facilitating persistent infection. Larger prospective studies of T-cell activation markers for ascertaining the association between cellular markers and clinical surrogates of disease activity in MS are warranted.

New antigens for serologic diagnosis of neuroborreliosis in children

OBJECTIVE

To evaluate serology with novel Borrelia-specific protein or peptide antigens in the laboratory diagnosis of neuroborreliosis (NB) in children.

METHODS

The performance of enzyme-linked immunosorbent assays with several recombinant borrelial protein antigens and invariable region 6 synthetic peptide antigen and of a commercial enzyme-linked immunosorbent assay with the flagella antigen were evaluated in the serodiagnosis and follow-up of children with clinical suspicion of NB. Serum samples were obtained from 20 children with neurologic symptoms indicative of NB. The patients were retrospectively divided into 2 groups based on the laboratory tests at presentation indicating definite (n = 7) or probable (n = 13) NB.

RESULTS

In addition to cerebrospinal fluid (CSF) lymphocytic pleocytosis and CSF antiflagella antibodies, all 7 patients with definite NB had serum IgG antibodies to at least 2 of the 3 novel antigens at presentation. The 13 patients with probable NB had variable laboratory findings: CSF pleocytosis (n = 7), CSF antiflagella IgM antibodies (n = 4), serum antiflagella IgM and/or IgG antibodies (n = 10). Of these 13 patients, 7 had serum IgG antibodies to 2 of the 3 novel antigens at presentation. During long term follow-up, serum anti-invariable region 6 antibodies disappeared.

CONCLUSIONS

The present study suggests that assessment of serum antibodies to a panel of Borrelia-specific antigens could improve the laboratory diagnosis of NB at presentation.

Diagnosis of lyme borreliosis

A large amount of knowledge has been acquired since the original descriptions of Lyme borreliosis (LB) and of its causative agent, Borrelia burgdorferi sensu stricto. The complexity of the organism and the variations in the clinical manifestations of LB caused by the different B. burgdorferi sensu lato species were not then anticipated. Considerable improvement has been achieved in detection of B. burgdorferi sensu lato by culture, particularly of blood specimens during early stages of disease. Culturing plasma and increasing the volume of material cultured have accomplished this. Further improvements might be obtained if molecular methods are used for detection of growth in culture and if culture methods are automated. Unfortunately, culture is insensitive in extracutaneous manifestations of LB. PCR and culture have high sensitivity on skin samples of patients with EM whose diagnosis is based mostly on clinical recognition of the lesion. PCR on material obtained from extracutaneous sites is in general of low sensitivity, with the exception of synovial fluid. PCR on synovial fluid has shown a sensitivity of up to >90% (when using four different primer sets) in patients with untreated or partially treated Lyme arthritis, making it a helpful confirmatory test in these patients. Currently, the best use of PCR is for confirmation of the clinical diagnosis of suspected Lyme arthritis in patients who are IgG immunoblot positive. PCR should not be used as the sole laboratory modality to support a clinical diagnosis of extracutaneous LB. PCR positivity in seronegative patients suspected of having late manifestations of LB most likely represents a false-positive result. Because of difficulties in direct methods of detection, laboratory tests currently in use are mainly those detecting antibodies to B. burgdorferi sensu lato. Tests used to detect antibodies to B. burgdorferi sensu lato have evolved from the initial formats as more knowledge on the immunodominant antigens has been collected. The recommendation for two-tier testing was an attempt to standardize testing and improve specificity in the United States. First-tier assays using whole-cell sonicates of B. burgdorferi sensu lato need to be standardized in terms of antigen composition and detection threshold of specific immunoglobulin classes. The search for improved serologic tests has stimulated the development of recombinant protein antigens and the synthesis of specific peptides from immunodominant antigens. The use of these materials alone or in combination as the source of antigen in a single-tier immunoassay may someday replace the currently recommended two-tier testing strategy. Evaluation of these assays is currently being done, and there is evidence that certain of these antigens may be broadly cross-reactive with the B. burgdorferi sensu lato species causing LB in Europe.

Improvement in the laboratory recognition of lyme borreliosis with the combination of culture and PCR methods

BACKGROUND

Lyme disease is a multisystem, multistage infection caused by three genospecies of the Borrelia burgdorferi sensu lato species. The diagnosis of Lyme disease is based on a history of tick-bite, physical examination, and serological tests. In the seronegative patients with Lyme borreliosis symptoms, additional testing should be introduced.

METHODS

The study group was composed of 240 hospitalized patients presented with various clinical symptoms suggesting Lyme borreliosis: 221 of the patients with neurological abnormalities and 19 with oligoarticular arthritis. Citrated blood and serum samples were collected from the patients for culture and serological examination, respectively. Moreover, 173 cerebrospinal and 6 synovial fluid samples were tested. New oligonucleotide primers based on B. burgdorferi sensu lato 16SrRNA gene sequences were designed for the detection of the bacteria in blood, cerebrospinal, and synovial fluid specimens with PCR. Levels of specific antibodies were measured in serum, cerebrospinal fluid and synovial fluid samples using ELISA and Western blot. B. burgdorferi spirochetes from blood, cerebrospinal fluid, and synovial fluid samples were cultured in cell line. Extracted and purified B. burgdorferi DNA was identified by PCR with new oligonucleotide primers. Then three genospecies were identified by PCR amplification with other primer sets specific for 16S rDNA and/or by the restriction fragment length polymorphism of 23S(rrl)-5S(rrf).

RESULTS

Bacterial DNA were found in samples from 32 patients, including 28 patients with neuroborreliosis and 4 with Lyme arthritis. B. burgdorferi-specific IgM and/or IgG serum antibodies were detected in 14 of these patients. Fourteen strains of Borrelia garini, 4 strains of Borrelia afzelii and 1 strain of B. burgdorferi sensu stricto were identified by PCR. Genospecies were not recognized in 13 specimens.

CONCLUSIONS

The procedure can be a rapid and sensitive diagnostic method for the detection of etiological agents in clinical materials derived from patients with the clinical symptoms of Lyme borreliosis. It can be utilized for both basic research as well as routine laboratory diagnosis.

Detection of genetic diversity in linear plasmids 28-3 and 36 in Borrelia burgdorferi sensu stricto isolates by subtractive hybridization

Recent studies based on sequence divergence in the ospC gene have identified limited subpopulations of B. burgdorferi associated with invasive human disease. Spirochetes with certain OspC types never cause human disease, while some others cause local infection at the primary skin site but do not hematogenously disseminate. Only four OspC genotypes (A, B, I and K) are responsible for disseminated disease and are found in the blood and cerebrospinal fluid, and hence are termed invasive strains. Subtractive hybridization was carried out between a prototype of a low passage invasive type, strain B31, and a strain associated only with local infection, group E, to identify genes associated with hematogenous dissemination. Two clones isolated from the subtraction library were unique to the B31 genome and mapped to locus BBH26 located on linear plasmid 28-3 (lp28-3) and to locus BBK48 located on linear plasmid 36 (lp36). Sequence analysis of the BBH26 locus revealed an amino acid repeat motif in the group E DNA that was absent in the B31 genome. This in-frame repeat motif was present yet variable in DNA isolated from several major OspC groups. However, no consistent sequence diversity was noted when other invasive and non-invasive strains were compared. In contrast, analysis of the BBK48 locus revealed a striking distinction between invasive and non-invasive spirochetes. PCR and Southern blot analysis indicated this locus was only present in invasive groups A, B, I, and K. BBK48 is a member of a gene family clustered on lp36. Therefore, these findings indicate that this genetic loci may participate in differentiating pathogens from non-pathogens and that its presence, which is correlated with ospC type, may play a role determining infectivity in humans.

The Lyme disease controversies continue

Within both the biomedical and lay community, Lyme disease continues to evoke considerable disagreements, especially regarding its diagnosis, patient management and treatment. A recent article of mine, published in this journal, dealing primarily with therapy for Lyme disease, subsequently led to a highly critical commentary on some of its content. Too often, however, the authors of these criticisms came to premature conclusions based mostly on little or no published data. Instead, they relied almost exclusively on highly speculative theories and on citing the uncorroborated published or unpublished findings and anecdotal reports of others in an attempt to substantiate their weak claims. In this reply account of mine, I respond by providing compelling evidence, derived primarily from the extensive peer-reviewed published literature, that runs counter to most of their key critical concerns. Another goal here is to further clarify certain inconsistencies, related to the epidemiology and microbiology of Lyme disease and its causative agent, including the dubious 'cyst forms', that have an important bearing on therapy.

Long-term follow-up of patients with culture-confirmed Lyme disease

PURPOSE

To determine the long-term outcome of patients with culture-confirmed Lyme disease.

METHODS

We analyzed data collected prospectively on adult patients from a highly endemic area in New York State who were diagnosed with early Lyme disease between 1991 and 1994. Patients with culture-confirmed erythema migrans were evaluated at baseline, 7 to 10 days, 21 to 28 days, 3 months, 6 months, 1 year, and annually thereafter. All patients were treated with antibiotics at the time of diagnosis.

RESULTS

We evaluated 96 cases on 709 separate occasions (median, eight evaluations per case). The erythema migrans rash resolved within 3 weeks in all of the 94 evaluable cases, none of whom developed an objective extracutaneous manifestation of Lyme disease. Of the 81 cases who were followed for >/=1 year, all but 8 (10%) were asymptomatic at their last visit, a mean (+/- SD) of 5.6 +/- 2.6 years into follow-up, and only 3 (4%) were symptomatic at every follow-up visit. Intercurrent tick bites were reported by 45 cases (47%), and 14 (15%) developed a second episode of erythema migrans. Four other cases who were asymptomatic seroconverted between years 2 and 5.

CONCLUSION

The long-term outcome of patients with erythema migrans after antibiotic therapy was excellent, but patients from a highly endemic area in New York State remained at high risk of re-exposure to ticks and reinfection. Subjective symptoms during follow-up evaluations tended to be mild to moderate, intermittent, and associated with more symptomatic illness at the time of initial diagnosis.

Linear and circular plasmid content in Borrelia burgdorferi clinical isolates

The genome of Borrelia burgdorferi, the etiologic agent of Lyme disease, is composed of a linear chromosome and more than 20 linear and circular plasmids. Typically, plasmid content analysis has been carried out by pulsed-field gel electrophoresis and confirmed by Southern hybridization. However, multiple plasmids of virtually identical sizes (e.g., lp28 and cp32) complicate the interpretation of such data. The present study was undertaken to investigate the complete plasmid complements of B. burgdorferi clinical isolates cultivated from patients from a single region where early Lyme disease is endemic. A total of 21 isolates obtained from the skin biopsy or blood samples of Lyme disease patients were examined for their complete plasmid complements by Southern hybridization and plasmid-specific PCR analysis. All clinical isolates harbored at least six of the nine previously characterized cp32s. Fourteen isolates harbored all B31-like linear plasmids, and seven isolates simultaneously lacked lp56, lp38, and some segments of lp28-1. The distinctive plasmid profile observed in these seven isolates was specific to organisms that had ribosomal spacer type 2 and pulsed-field gel type A, which implies a clonal origin for this genotype. The presence of nearly identical complements of multiple linear and circular plasmids in all of the human isolates suggests that these plasmids may be particularly necessary for infection, adaptation, and/or maintenance in the infected host.

Species-specific serodiagnosis of Lyme arthritis and neuroborreliosis due to Borrelia burgdorferi sensu stricto, B. afzelii, and B. garinii by using decorin binding protein A

The antigenic potential of decorin binding protein A (DbpA) was evaluated in serodiagnosis of human Lyme borreliosis (LB). The dbpA was cloned and sequenced from the three pathogenic Borrelia species common in Europe. Sequence analysis revealed high interspecies heterogeneity. The identity of the predicted amino acid sequences was 43 to 62% among Borrelia burgdorferi sensu stricto, B. afzelii, and B. garinii. The respective recombinant DbpAs (rDbpAs) were produced and tested as antigens by Western blotting and enzyme-linked immunosorbent assay (ELISA). One hundred percent of patients with neuroborreliosis (NB) and 93% of patients with Lyme arthritis (LA) reacted positively. Sera from the majority of patients reacted with one rDbpA only and had no or low cross-reactivity to other two variant proteins. In patients with culture-positive erythema migrans (EM), the sensitivity of rDbpA immunoglobulin G (IgG) or IgM ELISA was low. The DbpA seems to be a sensitive and specific antigen for the serodiagnosis of LA or NB, but not of EM, provided that variants from all three pathogenic borrelial species are included in the combined set of antigens.

Recent advances in the diagnosis of Lyme disease

Diagnosis of human Lyme borreliosis is usually based on serology, which has a number of pitfalls. In the early phase of the disease serology can still be negative, whereas false-positive results are also common. The interpretation of confirmatory Western blot tests is not always easy. Furthermore, routine serology cannot discriminate between active and past infection. In addition, recombinant antigens are being introduced to improve serologic tests. New developments in the diagnosis of Lyme disease are the development of PCR tests. This review gives an overview of the molecular diagnostic possibilities of Lyme borreliosis, mainly by PCR, and describes some interesting possibilities for future serology.

Efficacy of an evernimicin (SCH27899) in vitro and in an animal model of Lyme disease

The MICs of evernimicin at which 90% of Borrelia burgdorferi patient isolates were inhibited ranged from 0.1 to 0.5 microg/ml. Evernimicin was as effective as ceftriaxone against B. burgdorferi in a murine model of experimental Lyme disease. As assessed by culturing the urinary bladders of infected C3H mice, no live Borrelia isolates were recoverable following antibiotic treatment.

Isolation of Borrelia burgdorferi sensu lato from blood of children with solitary erythema migrans

OBJECTIVES

To establish the frequency of isolation of Borrelia burgdorferi sensu lato from blood of children with solitary erythema migrans (EM) in Europe, to determine the strains of the isolated borreliae and to compare the clinical course and the outcome of the disease according to positive and negative blood culture result.

METHODS

In the prospective study we included 134 consecutive patients younger than 15 years with solitary EM, referred to our institution in 1996 and 1997. One milliliter of blood was withdrawn before treatment and cultured in modified Kelly-Pettenkofer medium. Isolated borreliae were typed according to LRFP analysis. Patients were treated with either penicillin V or cefuroxime axetil for 14 days. The posttreatment course was surveyed by follow-up visits during 1 year.

RESULTS

B. burgdorferi sensu lato was isolated in 12 of 134 (9%) patients. Eleven blood isolates were typed: 10 were found to be B. afzelii and 1 was Borrelia garinii. Comparison of blood culture-positive and -negative patients revealed no differences in pretreatment characteristics or in posttreatment clinical course. However, worsening of local and/or systemic signs and symptoms at the beginning of antibiotic therapy (Jarish-Herxheimer's reaction) was identified more often in the blood culture-positive than in the blood culture-negative group (5 of 12 vs. 17 of 122, respectively; P = 0.0274).

CONCLUSIONS

The isolation rate of B. burgdorferi sensu lato from the blood of children with solitary EM was 9%. The majority of the isolates were B. afzelii. Blood culture-positive patients treated with oral antibiotics were not at greater risk for unfavorable course of the disease than patients with negative blood culture result.

Evaluation of a new culture medium for Borrelia burgdorferi

We evaluated the new MPM medium for the growth of Borrelia burgdorferi. All 18 blood samples from 17 patients with Lyme disease were negative. Growth studies showed that by day 4, most organisms in MPM were not viable. Our results reinforce the use of BSK medium as the primary choice for growing B. burgdorferi.

An indirect hemagglutination antibody test to detect antibodies to Borrelia burgdorferi in patients with Lyme disease

An indirect hemagglutination antibody (IHA) test was evaluated for its ability to detect borrelial antibodies in serum samples from patients with Lyme disease. The key test reagent developed for this antibody detection system was tannic acid-treated and glutaraldehyde-fixed sheep red blood cells (SRBC) containing Borrelia burgdorferi (Bb) antigens attached to the outer surface of the SRBC. In order to establish suitable cut-off titers, initial specificity and sensitivity measurements were made using sera from 100 anonymous healthy volunteers and 30 additional pre-determined samples known to be non-reactive or reactive for Lyme disease or syphilis. These results were compared with those obtained using a commercially available ELISA. At titers >/=64, the IHA test had a combined 98% specificity and 100% sensitivity for these 130 serum samples, 30 of which were known positives or negatives, whereas the ELISA was less specific (93%) and much less sensitive (80%). Subsequent testing was performed on sera from 65 patients with the erythema migrans (EM) rash and 20 patients with early disseminated (cardiac/neurologic) symptoms or with Lyme arthritis. At initial presentation, 46-48% of the EM patients had IHA reactivity, with titers >/=128, while 42% were positive in the ELISA. Follow-up testing performed on these EM patients, 8-12 days after receiving antibiotic treatment, revealed that Bb antibodies were detected best by the IHA test (83-86% reactive) relative to the ELISA (81% reactive). Bb antibodies were readily detectable on all of the serum samples from the early disseminated and late stage Lyme disease cases in both assay systems. Based on these results and because of its technical and interpretive simplicity, the IHA test should be considered as a useful and convenient alternative for the serological analysis of Bb infections.

Comparison of the yields of blood cultures using serum or plasma from patients with early Lyme disease

In an initial experiment, culture-grown Borrelia burgdorferi was added to freshly collected uninfected human blood. This in vitro study demonstrated that more spirochetes were distributed into the plasma than into the serum fraction. In a subsequent clinical study, B. burgdorferi was recovered from plasma cultures of approximately 50% of 42 patients with early Lyme disease associated with erythema migrans. The rate of recovery from plasma cultures was significantly greater than that from serum cultures (P < 0.001).

Conservation and heterogeneity of vlsE among human and tick isolates of Borrelia burgdorferi

The vls (variable major protein [VMP]-like sequence) locus of Borrelia burgdorferi encodes an antigenic variation system that closely resembles the VMP system of relapsing fever borreliae. To determine whether vls sequences are present consistently in low-passage, infectious isolates of B. burgdorferi, 22 blood and erythema migrans biopsy isolates from Lyme disease patients in Westchester County, New York, were examined by Southern blot and PCR analysis. Each of the strains contained a single plasmid varying in size from 21 to 38 kb that hybridized strongly with a vlsE probe based on the B. burgdorferi B31 sequence. In contrast, PCR products were obtained with only 10 of the 22 strains when primers corresponding to the 5' and 3' regions of the B31 vlsE sequence outside the variable cassette region were used. Only 2 of 16 B. burgdorferi-infected tick specimens yielded detectable PCR product. Eight of 10 strains that yielded a PCR product under these conditions were type 1 (a genotype with a high rate of dissemination), according to PCR-restriction fragment length polymorphism analysis of intergenic rDNA sequences, whereas the isolates that did not yield vlsE PCR products were either type 2 or type 3. Comparison of the sequences of cloned PCR products from the patient isolates indicated a high degree of identity to the B31 sequence, with most of the differences restricted to the hypervariable regions known to undergo sequence variation. Taken together, these results both reinforce previous evidence that vls sequences are present consistently in low-passage Lyme disease spirochetes and indicate that both highly conserved and heterogeneous subgroups exist with regard to vlsE sequences.

Human antibody responses to VlsE antigenic variation protein of Borrelia burgdorferi

VlsE is a 35-kDa surface-exposed lipoprotein of Borrelia burgdorferi that was shown previously to undergo antigenic variation through segmental recombination of silent vls cassettes with vlsE during experimental mouse infections. Previous data had indicated that sera from North American Lyme disease patients and experimentally infected animals contained antibodies reactive with VlsE. In this study, sera from patients with Lyme disease, syphilis, and autoimmune conditions as well as from healthy controls were examined for reactivity with VlsE by Western blotting and enzyme-linked immunosorbent assay (ELISA). Strong Western blot reactivity to a recombinant VlsE cassette region protein was obtained consistently with Lyme disease sera. Although sera from Lyme disease patients also reacted with a band corresponding to VlsE in B. burgdorferi B31-5A3, interpretation was complicated by low levels of VlsE expression in in vitro-cultured B. burgdorferi and by the presence of comigrating bands. An ELISA using recombinant VlsE was compared with an ELISA using sonically disrupted B. burgdorferi as the antigen. For a total of 93 Lyme disease patient sera examined, the VlsE ELISA yielded sensitivities of 63% for culture-confirmed erythema migrans cases and 92% for later stages, as compared to 61 and 98%, respectively, for the "whole-cell" ELISA. The specificities of the two assays with healthy blood donor sera were comparable, but the VlsE ELISA was 90% specific with sera from syphilis patients, compared to 20% specificity for the whole-cell ELISA with this group. Neither assay showed reactivity with a panel of sera from 20 non-Lyme disease arthritis patients or 20 systemic lupus erythematosus patients. Our results indicate that VlsE may be useful in the immunodiagnosis of Lyme disease and may offer greater specificity than ELISAs using whole B. burgdorferi as the antigen.

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.

Genetic diversity of Borrelia burgdorferi in lyme disease patients as determined by culture versus direct PCR with clinical specimens

Two hundred seventeen isolates of Borrelia burgdorferi originally cultured from skin biopsy samples or blood of early Lyme disease patients were genetically characterized by PCR-restriction fragment length polymorphism (RFLP) typing of the 16S-23S ribosomal DNA intergenic spacer. Three major RFLP types were observed. Of the cultured isolates, 63 of 217 (29.0%) were type 1, 85 of 217 (39.2%) were type 2, and 58 of 217 (26.7%) were type 3; mixtures of two RFLP types were obtained in 6.0% (13 of 217) of the cultures. Comparison of typing of B. burgdorferi performed directly on 51 patient skin specimens with typing of cultures originally isolated from the same tissue revealed that a much larger proportion of direct tissue samples had mixtures of RFLP types (43.1% by direct typing versus 5.9% by culture [P < 0.001). In addition, identical RFLP types were observed in only 35.5% (11 of 31) of the paired samples. RFLP type 3 organisms were recovered from blood at a significantly lower rate than were either type 1 or type 2 strains. These studies demonstrate that the genetic diversity of B. burgdorferi patient isolates as determined by cultivation differs from that assessed by PCR performed directly on patient tissue.

DbpA, but not OspA, is expressed by Borrelia burgdorferi during spirochetemia and is a target for protective antibodies

DbpA is a target for antibodies that protect mice against infection by cultured Borrelia burgdorferi. Infected mice exhibit early and sustained humoral responses to DbpA and DbpB, suggesting that these proteins are expressed in vivo. Many antigens expressed in mammals by B. burgdorferi are repressed in vitro at lower growth temperatures, and we have now extended these observations to include DbpA and DbpB. To confirm that the protective antigen DbpA is expressed in vivo and to address the question of its accessibility to antibodies during infection, we examined B. burgdorferi in blood samples from mice following cutaneous inoculation. B. burgdorferi was visualized by dark-field microscopy in plasma samples from spirochetemic mice, and an indirect immunofluorescence assay showed that these spirochetes were DbpA positive and OspA negative. We developed an ex vivo borreliacidal assay to show that hyperimmune antiserum against DbpA, but not OspA, killed these plasma-derived spirochetes, demonstrating that DbpA is accessible to antibodies during this phase of infection. Blood transferred from spirochetemic donor mice readily established B. burgdorferi infection in naive recipient mice or mice hyperimmunized with OspA, while mice hyperimmunized with DbpA showed significant protection against challenge with host-adapted spirochetes. Antiserum from persistently infected mice had borreliacidal activity against both cultured and plasma-derived spirochetes, and adsorption of this serum with DbpA substantially depleted this killing activity. Our observations show that immunization with DbpA blocks B. burgdorferi dissemination from the site of cutaneous inoculation and suggest that DbpA antibodies may contribute to control of persistent infection.

Lyme borreliosis

Lyme borreliosis (Lyme disease) is often said to be associated with "protean" manifestations, a reference to the ancient god Proteus, who could assume many forms and thus elude his pursuers. This legendary quality has clouded our understanding of Lyme borreliosis by giving Borrelia burgdorferi infection a mythical aura of its own. This review shows that this illness, while incompletely understood, is far more palpable than Proteus and is (in most cases) much more readily subdued. The clinical presentations of Lyme borreliosis do differ in North America and Eurasia, possibly due to the differing pathogenicity of distinct genospecies of Borrelia burgdorferi. The most common manifestation, however, in both continents is erythema migrans. Diagnosis should rest on a careful history and objective clinical findings, supported by appropriately chosen laboratory tests. Reports of coinfection with other tick-borne diseases should prompt a fresh look at Lyme borreliosis. Assertions about "protean manifestations" of B burgdorferi infection should be reappraised. Advances in laboratory techniques are welcome but culture remains the gold standard for the diagnosis--and no laboratory test result should substitute for careful clinical observation and critical analysis.