Persistence of Borrelia burgdorferi in ligamentous tissue from a patient with chronic Lyme borreliosis

HLA-DR-Expressing Fibroblast-Like Synoviocytes Are Inducible Antigen Presenting Cells That Present Autoantigens in Lyme Arthritis

OBJECTIVE

HLA-DR-expressing fibroblast-like synoviocytes (FLS) are a prominent cell type in synovial tissue in chronic inflammatory forms of arthritis. FLS-derived extracellular matrix (ECM) proteins, including fibronectin-1 (FN1), contain immunogenic CD4+ T cell epitopes in patients with postinfectious Lyme arthritis (LA). However, the role of FLS in presentation of these T cell epitopes remains uncertain.

METHODS

Primary LA FLS and primary murine FLS stimulated with interferon gamma (IFNγ), Borrelia burgdorferi, and/or B burgdorferi peptidoglycan (PG) were assessed for properties associated with antigen presentation. HLA-DR-presented peptides from stimulated LA FLS were identified by immunopeptidomics analysis. OT-II T cells were co-cultured with stimulated murine FLS in the presence of cognate ovalbumin antigen to determine the potential of FLS to act as inducible antigen presenting cells (APCs).

RESULTS

FLS expressed HLA-DR molecules within inflamed synovial tissue and tendons from patients with postinfectious LA in situ. Major histocompatibility complex (MHC) class II and co-stimulatory molecules were expressed by FLS following in vitro stimulation with IFNγ and B burgdorferi and presented both foreign and self-MHC-II peptides, including an immunogenic T cell epitope derived from Lyme autoantigen FN1. Stimulated FLS induced proliferation of naive OT-II CD4+ T cells that were dependent on OT-II antigen and CD40. Stimulation with B burgdorferi PG enhanced FLS-mediated T cell activation.

CONCLUSION

MHC-II+ FLS are inducible APCs that can induce CD4+ T cell activation in an antigen- and CD40-dependent manner. Activated FLS can also present ECM-derived Lyme autoantigens, implicating FLS in amplifying tissue-localized autoimmunity in LA.

Combining Double-Dose and High-Dose Pulsed Dapsone Combination Therapy for Chronic Lyme Disease/Post-Treatment Lyme Disease Syndrome and Co-Infections, Including Bartonella: A Report of 3 Cases and a Literature Review

Three patients with relapsing and remitting borreliosis, babesiosis, and bartonellosis, despite extended anti-infective therapy, were prescribed double-dose dapsone combination therapy (DDDCT) for 8 weeks, followed by one or several two-week courses of pulsed high-dose dapsone combination therapy (HDDCT). We discuss these patients' cases to illustrate three important variables required for long-term remission. First, diagnosing and treating active co-infections, including Babesia and Bartonella were important. Babesia required rotations of multiple anti-malarial drug combinations and herbal therapies, and Bartonella required one or several 6-day HDDCT pulses to achieve clinical remission. Second, all prior oral, intramuscular (IM), and/or intravenous (IV) antibiotics used for chronic Lyme disease (CLD)/post-treatment Lyme disease syndrome (PTLDS), irrespective of the length of administration, were inferior in efficacy to short-term pulsed biofilm/persister drug combination therapy i.e., dapsone, rifampin, methylene blue, and pyrazinamide, which improved resistant fatigue, pain, headaches, insomnia, and neuropsychiatric symptoms. Lastly, addressing multiple factors on the 16-point multiple systemic infectious disease syndrome (MSIDS) model was important in achieving remission. In conclusion, DDDCT with one or several 6-7-day pulses of HDDCT, while addressing abnormalities on the 16-point MSIDS map, could represent a novel effective clinical and anti-infective strategy in CLD/PTLDS and associated co-infections including Bartonella.

Human Tick-Borne Diseases and Advances in Anti-Tick Vaccine Approaches: A Comprehensive Review

This comprehensive review explores the field of anti-tick vaccines, addressing their significance in combating tick-borne diseases of public health concern. The main objectives are to provide a brief epidemiology of diseases affecting humans and a thorough understanding of tick biology, traditional tick control methods, the development and mechanisms of anti-tick vaccines, their efficacy in field applications, associated challenges, and future prospects. Tick-borne diseases (TBDs) pose a significant and escalating threat to global health and the livestock industries due to the widespread distribution of ticks and the multitude of pathogens they transmit. Traditional tick control methods, such as acaricides and repellents, have limitations, including environmental concerns and the emergence of tick resistance. Anti-tick vaccines offer a promising alternative by targeting specific tick proteins crucial for feeding and pathogen transmission. Developing vaccines with antigens based on these essential proteins is likely to disrupt these processes. Indeed, anti-tick vaccines have shown efficacy in laboratory and field trials successfully implemented in livestock, reducing the prevalence of TBDs. However, some challenges still remain, including vaccine efficacy on different hosts, polymorphisms in ticks of the same species, and the economic considerations of adopting large-scale vaccine strategies. Emerging technologies and approaches hold promise for improving anti-tick vaccine development and expanding their impact on public health and agriculture.

Human leukocyte antigen HLA-DR-expressing fibroblast-like synoviocytes are inducible antigen presenting cells that present autoantigens in Lyme arthritis

Background

HLA-DR-expressing fibroblast-like synoviocytes (FLS) are a prominent cell type in synovial tissue in chronic inflammatory forms of arthritis. We recently showed that peptides from several extracellular matrix (ECM) proteins, including fibronectin-1 (FN1), contained immunogenic CD4+ T cell epitopes in patients with postinfectious Lyme arthritis (LA). However, the role of FLS in presentation of these T cell epitopes remains uncertain.

Methods

Primary LA FLS and primary murine FLS stimulated with interferon gamma (IFNγ), Borrelia burgdorferi, and/or B. burgdorferi peptidoglycan (PG) were assessed for properties associated with antigen presentation. HLA-DR-presented peptides from stimulated LA FLS were identified by immunopeptidomics analysis. OT-II T cells were cocultured with stimulated murine FLS in the presence of cognate ovalbumin antigen to determine the potential of FLS to act as inducible antigen presenting cells (APC).

Results

FLS expressed HLA-DR molecules within inflamed synovial tissue and tendons from patients with post-infectious LA patients in situ. MHC class II and costimulatory molecules were expressed by FLS following in vitro stimulation with IFNγ and B. burgdorferi and presented both foreign and self MHC-II peptides, including T cell epitopes derived from two Lyme autoantigens fibronectin-1 (FN1) and endothelial cell growth factor (ECGF). Stimulated murine FLS induced proliferation of naïve OT-II CD4+ T cells, particularly when FLS were stimulated with both IFNγ and PG.

Conclusions

MHC-II+ FLS are inducible APCs that can induce CD4+ T cell activation and can present Lyme autoantigens derived from ECM proteins, thereby amplifying tissue-localized autoimmune CD4+ T cell responses in LA.

Comparison of the Efficacy of Longer versus Shorter Pulsed High Dose Dapsone Combination Therapy in the Treatment of Chronic Lyme Disease/Post Treatment Lyme Disease Syndrome with Bartonellosis and Associated Coinfections

Twenty-five patients with relapsing and remitting Borreliosis, Babesiosis, and bartonellosis despite extended anti-infective therapy were prescribed double-dose dapsone combination therapy (DDDCT), followed by one or several courses of High Dose Dapsone Combination Therapy (HDDCT). A retrospective chart review of these 25 patients undergoing DDDCT therapy and HDDCT demonstrated that 100% improved their tick-borne symptoms, and patients completing 6-7 day pulses of HDDCT had superior levels of improvement versus 4-day pulses if Bartonella was present. At the completion of treatment, 7/23 (30.5%) who completed 8 weeks of DDDCT followed by a 5-7 day pulse of HDDCT remained in remission for 3-9 months, and 3/23 patients (13%) who recently finished treatment were 1 ½ months in full remission. In conclusion, DDDCT followed by 6-7 day pulses of HDDCT could represent a novel, effective anti-infective strategy in chronic Lyme disease/Post Treatment Lyme Disease Syndrome (PTLDS) and associated co-infections, including Bartonella, especially in individuals who have failed standard antibiotic protocols.

Adhesion of human pathogenic bacteria to endothelial cells is facilitated by fibronectin interaction

Human pathogenic bacteria circulating in the bloodstream need to find a way to interact with endothelial cells (ECs) lining the blood vessels to infect and colonise the host. The extracellular matrix (ECM) of ECs might represent an attractive initial target for bacterial interaction, as many bacterial adhesins have reported affinities to ECM proteins, in particular to fibronectin (Fn). Here, we analysed the general role of EC-expressed Fn for bacterial adhesion. For this, we evaluated the expression levels of ECM coding genes in different ECs, revealing that Fn is the highest expressed gene and thereby, it is highly abundant in the ECM environment of ECs. The role of Fn as a mediator in bacterial cell-host adhesion was evaluated in adhesion assays of Acinetobacter baumannii, Bartonella henselae, Borrelia burgdorferi, and Staphylococcus aureus to ECs. The assays demonstrated that bacteria colocalised with Fn fibres, as observed by confocal laser scanning microscopy. Fn removal from the ECM environment (FN1 knockout ECs) diminished bacterial adherence to ECs in both static and dynamic adhesion assays to varying extents, as evaluated via absolute quantification using qPCR. Interactions between adhesins and Fn might represent the crucial step for the adhesion of human-pathogenic Gram-negative and Gram-positive bacteria targeting the ECs as a niche of infection.

Persistent Borrelia burgdorferi Sensu Lato Infection after Antibiotic Treatment: Systematic Overview and Appraisal of the Current Evidence from Experimental Animal Models

Lyme borreliosis is caused by spirochetes belonging to the Borrelia burgdorferi sensu lato group, which are transmitted by Ixodes tick species living in the temperate climate zones of the Northern Hemisphere. The clinical manifestations of Lyme borreliosis are diverse and treated with oral or intravenous antibiotics. In some patients, long-lasting and debilitating symptoms can persist after the recommended antibiotic treatment. The etiology of such persisting symptoms is under debate, and one hypothesis entails persistent infection by a subset of spirochetes after antibiotic therapy. Here, we review and appraise the experimental evidence from in vivo animal studies on the persistence of B. burgdorferi sensu lato infection after antibiotic treatment, focusing on the antimicrobial agents doxycycline and ceftriaxone. Our review indicates that some in vivo animal studies found sporadic positive cultures after antibiotic treatment. However, this culture positivity often seemed to be related to inadequate antibiotic treatment, and the few positive cultures in some studies could not be reproduced in other studies. Overall, current results from animal studies provide insufficient evidence for the persistence of viable and infectious spirochetes after adequate antibiotic treatment. Borrelial nucleic acids, on the contrary, were frequently detected in these animal studies and may thus persist after antibiotic treatment. We put forward that research into the pathogenesis of persisting complaints after antibiotic treatment for Lyme borreliosis in humans should be a top priority, but future studies should most definitely also focus on explanations other than persistent B. burgdorferi sensu lato infection after antibiotic treatment.

Efficacy of Short-Term High Dose Pulsed Dapsone Combination Therapy in the Treatment of Chronic Lyme Disease/Post-Treatment Lyme Disease Syndrome (PTLDS) and Associated Co-Infections: A Report of Three Cases and Literature Review

Lyme disease and associated co-infections are increasing worldwide and approximately 20% of individuals develop chronic Lyme disease (CLD)/Post-Treatment Lyme Disease Syndrome (PTLDS) despite early antibiotics. A seven- to eight-week protocol of double dose dapsone combination therapy (DDDCT) for CLD/PTLDS results in symptom remission in approximately 50% of patients for one year or longer, with published culture studies indicating higher doses of dapsone demonstrate efficacy against resistant biofilm forms of Borrelia burgdorferi. The purpose of this study was, therefore, to evaluate higher doses of dapsone in the treatment of resistant CLD/PTLDS and associated co-infections. A total of 25 patients with a history of Lyme and associated co-infections, most of whom had ongoing symptoms despite several courses of DDDCT, took one or more courses of high dose pulsed dapsone combination therapy (200 mg dapsone × 3–4 days and/or 200 mg BID × 4 days), depending on persistent symptoms. The majority of patients noticed sustained improvement in eight major Lyme symptoms, including fatigue, pain, headaches, neuropathy, insomnia, cognition, and sweating, where dapsone dosage, not just the treatment length, positively affected outcomes. High dose pulsed dapsone combination therapy may represent a novel therapeutic approach for the treatment of resistant CLD/PTLDS, and should be confirmed in randomized, controlled clinical trials.

Real time micro-organisms PCR in 104 patients with polymorphic signs and symptoms that may be related to a tick bite

INTRODUCTION

Ticks are frequently polyinfected and can thus transmit numerous microorganisms. A large number of bacteria, parasites and viruses are transmitted by tick bites and could cause different signs and symptoms in patients. The main goal of this study was to search for these numerous microorganisms in patients presenting with persistent polymorphic syndrome possibly due to a tick bite (SPPT).

PATIENTS AND METHODS

The following microorganisms were searched for in saliva, urine, venous and capillary blood by using real time PCR: Borrelia burgdorferi sensu lato, Borrelia miyamotoi, Borrelia hermsii, Bartonella spp., Bartonella quintana, Bartonella henselae, Ehrlichia spp., Anaplasma spp., Rickettsia spp., Coxiella burnetii, Brucella spp., Francisella tularensis, Mycoplasma spp., Chlamydia spp., Babesia spp., Theileria spp.

RESULTS

104 patients were included. 48% of the patients were poly-infected, and 25% harboured at least three different microorganisms. Borrelia spp. were not the most frequent bacteria observed, observed far behind Mycoplasma spp., Rickettsia spp. and Ehrlichia spp. which were the most frequent microorganisms observed. Piroplasms were found in a significant number of patients. The most sensitive matrix was saliva, followed by urine, capillary blood and venous blood.

CONCLUSION

Our prospective study has shown that patients with SPPT, a syndrome close to fibromyalgia, could harbour several tick borne microorganisms.

"Repurposing" Disulfiram in the Treatment of Lyme Disease and Babesiosis: Retrospective Review of First 3 Years' Experience in One Medical Practice

A total of 71 patients with Lyme disease were identified for analysis in whom treatment with disulfiram was initiated between 15 March 2017 and 15 March 2020. Four patients were lost to follow-up, leaving 67 evaluable patients. Our retrospective review found patients to fall into a “high-dose” group (≥4 mg/kg/day) and a “low-dose” group (<4 mg/kg/day). In total, 62 of 67 (92.5%) patients treated with disulfiram were able to endorse a net benefit of the treatment with regard to their symptoms. Moreover, 12 of 33 (36.4%) patients who completed one or two courses of “high-dose” therapy enjoyed an “enduring remission”, defined as remaining clinically well for ≥6 months without further anti-infective treatment. The most common adverse reactions from disulfiram treatment in the high-dose group were fatigue (66.7%), psychiatric symptoms (48.5%), peripheral neuropathy (27.3%), and mild to moderate elevation of liver enzymes (15.2%). We observed that although patients on high dose experienced a higher risk for adverse reactions than those on a low dose, high-dose patients were significantly more likely to achieve enduring remission.

Freeman P. Efficacy of Double-Dose Dapsone Combination Therapy in the Treatment of Chronic Lyme Disease/Post-Treatment Lyme Disease Syndrome (PTLDS) and Associated Co-infections: A Report of Three Cases and Retrospective Chart Review

Three patients with multi-year histories of relapsing and remitting Lyme disease and associated co-infections despite extended antibiotic therapy were each given double-dose dapsone combination therapy (DDD CT) for a total of 7-8 weeks. At the completion of therapy, all three patients' major Lyme symptoms remained in remission for a period of 25-30 months. A retrospective chart review of 37 additional patients undergoing DDD CT therapy (40 patients in total) was also performed, which demonstrated tick-borne symptom improvements in 98% of patients, with 45% remaining in remission for 1 year or longer. In conclusion, double-dose dapsone therapy could represent a novel and effective anti-infective strategy in chronic Lyme disease/ post-treatment Lyme disease syndrome (PTLDS), especially in those individuals who have failed regular dose dapsone combination therapy (DDS CT) or standard antibiotic protocols. A randomized, blinded, placebo-controlled trial is warranted to evaluate the efficacy of DDD CT in those individuals with chronic Lyme disease/PTLDS.

A Practical Approach to the Diagnosis of Lyme Borreliosis: From Clinical Heterogeneity to Laboratory Methods

Clinical evaluation of Lyme Borreliosis (LB) is the starting point for its diagnosis. The patient's medical history and clinical symptoms are fundamental for disease recognition. The heterogeneity in clinical manifestations of LB can be related to different causes, including the different strains of Borrelia, possible co-infection with other tick transmitted pathogens, and its interactions with the human host. This review aims at describing the heterogeneous symptoms of Lyme Borreliosis, as well as offering a practical approach for recognition of the disease, both in terms of clinical features and diagnostic/research tools.

Presentation of Acrodermatitis Chronica Atrophicans Rashes on Lyme Disease Patients in Canada

Lyme disease (Lyme borreliosis) is a complex multisystem illness with varying clinical manifestations. This tick-borne zoonosis is caused by the spirochetal bacterium, Borrelia burgdorferi sensu lato (Bbsl) and, worldwide, presents with at least 20 different types of rashes. Certain cutaneous rashes are inherently interconnected to various stages of Lyme disease. In this study, five Canadian Lyme disease patients from a multi-age range presented various phases of the acrodermatitis chronica atrophicans (ACA) rash. In each case of ACA, the underlying etiological pathogen was the Lyme disease spirochete. Although ACA rashes are normally found on the lower extremities, this study illustrates that ACA rashes are not directly correlated with a tick bite, geographic area, age, Bbsl genospecies, exercise, or any given surface area of the body. Case 4 provides confirmation for an ACA rash and gestational Lyme disease. One patient (Case 5) puts forth a Bbsl and Bartonella sp. co-infection with a complex ACA rash. This study documents ACA rashes on Lyme disease patients for the first time in Canada.

Monitoring of Nesting Songbirds Detects Established Population of Blacklegged Ticks and Associated Lyme Disease Endemic Area in Canada

This study provides a novel method of documenting established populations of bird-feeding ticks. Single populations of the blacklegged tick, Ixodes scapularis, and the rabbit tick, Haemaphysalis leporispalustris, were revealed in southwestern Québec, Canada. Blacklegged tick nymphs and, similarly, larval and nymphal rabbit ticks were tested for the Lyme disease bacterium, Borrelia burgdorferi sensu lato (Bbsl), using PCR and the flagellin (flaB) gene, and 14 (42%) of 33 of blacklegged tick nymphs tested were positive. In contrast, larval and nymphal H. leporsipalustris ticks were negative for Bbsl. The occurrence of Bbsl in I. scapularis nymphs brings to light the presence of a Lyme disease endemic area at this songbird nesting locality. Because our findings denote that this area is a Lyme disease endemic area, and I. scapularis is a human-biting tick, local residents and outdoor workers must take preventive measures to avoid tick bites. Furthermore, local healthcare practitioners must include Lyme disease in their differential diagnosis.

Chronic Lyme Disease: An Evidence-Based Definition by the ILADS Working Group

Objective: Chronic Lyme disease has been a poorly defined term and often dismissed as a fictitious entity. In this paper, the International Lyme and Associated Diseases Society (ILADS) provides its evidence-based definition of chronic Lyme disease. Definition: ILADS defines chronic Lyme disease (CLD) as a multisystem illness with a wide range of symptoms and/or signs that are either continuously or intermittently present for a minimum of six months. The illness is the result of an active and ongoing infection by any of several pathogenic members of the Borrelia burgdorferi sensu lato complex (Bbsl). The infection has variable latency periods and signs and symptoms may wax, wane and migrate. CLD has two subcategories, CLD, untreated (CLD-U) and CLD, previously treated (CLD-PT). The latter requires that CLD manifestations persist or recur following treatment and are present continuously or in a relapsing/remitting pattern for a duration of six months or more. Methods: Systematic review of over 250 peer reviewed papers in the international literature to characterize the clinical spectrum of CLD-U and CLD-PT. Conclusion: This evidence-based definition of chronic Lyme disease clarifies the term's meaning and the literature review validates that chronic and ongoing Bbsl infections can result in chronic disease. Use of this CLD definition will promote a better understanding of the infection and facilitate future research of this infection.

Detection and Transstadial Passage of Babesia Species and Borrelia burgdorferi Sensu Lato in Ticks Collected from Avian and Mammalian Hosts in Canada

Lyme disease and human babesiosis are the most common tick-borne zoonoses in the Temperate Zone of North America. The number of infected patients has continued to rise globally, and these zoonoses pose a major healthcare threat. This tick-host-pathogen study was conducted to test for infectious microbes associated with Lyme disease and human babesiosis in Canada. Using the flagellin (flaB) gene, three members of the Borrelia burgdorferi sensu lato (Bbsl) complex were detected, namely a Borrelia lanei-like spirochete, Borrelia burgdorferi sensu stricto (Bbss), and a distinct strain that may represent a separate Bbsl genospecies. This novel Bbsl strain was detected in a mouse tick, Ixodes muris, collected from a House Wren, Troglodytes aedon, in Quebec during the southward fall migration. The presence of Bbsl in bird-feeding larvae of I. muris suggests reservoir competency in three passerines (i.e., Common Yellowthroat, House Wren, Magnolia Warbler). Based on the 18S ribosomal RNA (rRNA) gene, three Babesia species (i.e., Babesia divergens-like, Babesia microti, Babesia odocoilei) were detected in field-collected ticks. Not only was B. odocoilei found in songbird-derived ticks, this piroplasm was apparent in adult questing blacklegged ticks, Ixodes scapularis, in southern Canada. By allowing live, engorged ticks to molt, we confirm the transstadial passage of Bbsl in I. muris and B. odocoilei in I. scapularis. Bbss and Babesia microti were detected concurrently in a groundhog tick, Ixodes cookei, in Western Ontario. In Alberta, a winter tick, Dermacentor albipictus, which was collected from a moose, Alces alces, tested positive for Bbss. Notably, a B. divergens-like piroplasm was detected in a rabbit tick, Haemaphysalis leporispalustris, collected from an eastern cottontail in southern Manitoba; this Babesia species is a first-time discovery in Canada. This rabbit tick was also co-infected with Borrelia lanei-like spirochetes, which constitutes a first in Canada. Overall, five ticks were concurrently infected with Babesia and Bbsl pathogens and, after the molt, could potentially co-infect humans. Notably, we provide the first authentic report of I. scapularis ticks co-infected with Bbsl and B. odocoilei in Canada. The full extent of infectious microorganisms transmitted to humans by ticks is not fully elucidated, and clinicians need to be aware of the complexity of these tick-transmitted enzootic agents on human health. Diagnosis and treatment must be administered by those with accredited medical training in tick-borne zoonosis.

The Long-Term Persistence of Borrelia burgdorferi Antigens and DNA in the Tissues of a Patient with Lyme Disease

Whether Borrelia burgdorferi, the causative agent of Lyme disease, can persist for long periods in the human body has been a controversial question. The objective of this study was to see if we could find B. burgdorferi in a Lyme disease patient after a long clinical course and after long-term antibiotic treatment. Therefore, we investigated the potential presence of B. burgdorferi antigens and DNA in human autopsy tissues from a well-documented serum-, PCR-, and culture-positive Lyme disease patient, a 53-year-old female from northern Westchester County in the lower Hudson Valley Region of New York State, who had received extensive antibiotic treatments during extensive antibiotic treatments over the course of her 16-year-long illness. We also asked what form the organism might take, with special interest in the recently found antibiotic-resistant aggregate form, biofilm. We also examined the host tissues for the presence of inflammatory markers such as CD3+ T lymphocytes. Autopsy tissue sections of the brain, heart, kidney, and liver were analyzed by histological and immunohistochemical methods (IHC), confocal microscopy, fluorescent in situ hybridization (FISH), polymerase chain reaction (PCR), and whole-genome sequencing (WGS)/metagenomics. We found significant pathological changes, including borrelial spirochetal clusters, in all of the organs using IHC combined with confocal microscopy. The aggregates contained a well-established biofilm marker, alginate, on their surfaces, suggesting they are true biofilm. We found B. burgdorferi DNA by FISH, polymerase chain reaction (PCR), and an independent verification by WGS/metagenomics, which resulted in the detection of B. burgdorferi sensu stricto specific DNA sequences. IHC analyses showed significant numbers of infiltrating CD3+ T lymphocytes present next to B. burgdorferi biofilms. In summary, we provide several lines of evidence that suggest that B. burgdorferi can persist in the human body, not only in the spirochetal but also in the antibiotic-resistant biofilm form, even after long-term antibiotic treatment. The presence of infiltrating lymphocytes in the vicinity of B. burgdorferi biofilms suggests that the organism in biofilm form might trigger chronic inflammation.

Disulfiram (Tetraethylthiuram Disulfide) in the Treatment of Lyme Disease and Babesiosis: Report of Experience in Three Cases

Three patients, each of whom had required intensive open-ended antimicrobial therapy for control of the symptoms of chronic relapsing neurological Lyme disease and relapsing babesiosis, were able to discontinue treatment and remain clinically well for periods of observation of 6–23 months following the completion of a finite course of treatment solely with disulfiram. One patient relapsed at six months and is being re-treated with disulfiram.

Metamorphoses of Lyme disease spirochetes: phenomenon of Borrelia persisters

The survival of spirochetes from the Borrelia burgdorferi (sensu lato) complex in a hostile environment is achieved by the regulation of differential gene expression in response to changes in temperature, salts, nutrient content, acidity fluctuation, multiple host or vector dependent factors, and leads to the formation of dormant subpopulations of cells. From the other side, alterations in the level of gene expression in response to antibiotic pressure leads to the establishment of a persisters subpopulation. Both subpopulations represent the cells in different physiological states. "Dormancy" and "persistence" do share some similarities, e.g. both represent cells with low metabolic activity that can exist for extended periods without replication, both constitute populations with different gene expression profiles and both differ significantly from replicating forms of spirochetes. Persisters are elusive, present in low numbers, morphologically heterogeneous, multi-drug-tolerant cells that can change with the environment. The definition of "persisters" substituted the originally-used term "survivors", referring to the small bacterial population of Staphylococcus that survived killing by penicillin. The phenomenon of persisters is present in almost all bacterial species; however, the reasons why Borrelia persisters form are poorly understood. Persisters can adopt varying sizes and shapes, changing from well-known forms to altered morphologies. They are capable of forming round bodies, L-form bacteria, microcolonies or biofilms-like aggregates, which remarkably change the response of Borrelia to hostile environments. Persisters remain viable despite aggressive antibiotic challenge and are able to reversibly convert into motile forms in a favorable growth environment. Persisters are present in significant numbers in biofilms, which has led to the explanation of biofilm tolerance to antibiotics. Considering that biofilms are associated with numerous chronic diseases through their resilient presence in the human body, it is not surprising that interest in persisting cells has consequently accelerated. Certain diseases caused by pathogenic bacteria (e.g. tuberculosis, syphilis or leprosy) are commonly chronic in nature and often recur despite antibiotic treatment. Three decades of basic and clinical research have not yet provided a definite answer to the question: is there a connection between persisting spirochetes and recurrence of Lyme disease in patients?

Presence of Babesia odocoilei and Borrelia burgdorferi Sensu Stricto in a Tick and Dual Parasitism of Amblyomma inornatum and Ixodes scapularis on a Bird in Canada

Wild birds transport ticks into Canada that harbor a diversity of zoonotic pathogens. However, medical practitioners often question how these zoonotic pathogens are present in their locality. In this study, we provide the first report of an Amblyomma inornatum tick cofeeding with a blacklegged tick, Ixodes scapularis, which parasitized a Veery, Catharus fuscescens—a neotropical songbird. Using the flagellin (flaB) gene of the Lyme disease bacterium, Borrelia burgdorferi sensu lato, and the 18S rRNA gene of the Babesia piroplasm, a malaria-like microorganism, we detected Borrelia burgdorferi sensu stricto and Babesia odocoilei, respectively, in an I. scapularis nymph. After the molt, these ticks can bite humans. Furthermore, this is the first documentation of B. odocoilei in a tick parasitizing a bird. Our findings substantiate the fact that migratory songbirds transport neotropical ticks long distances, and import them into Canada during northward spring migration. Health care practitioners need to be aware that migratory songbirds transport pathogen-laden ticks into Canada annually, and pose an unforeseen health risk to Canadians.

Far-Reaching Dispersal of Borrelia burgdorferi Sensu Lato-Infected Blacklegged Ticks by Migratory Songbirds in Canada

Lyme disease has been documented in northern areas of Canada, but the source of the etiological bacterium, Borrelia burgdorferi sensu lato (Bbsl) has been in doubt. We collected 87 ticks from 44 songbirds during 2017, and 24 (39%) of 62 nymphs of the blacklegged tick, Ixodes scapularis, were positive for Bbsl. We provide the first report of Bbsl-infected, songbird-transported I. scapularis in Cape Breton, Nova Scotia; Newfoundland and Labrador; north-central Manitoba, and Alberta. Notably, we report the northernmost account of Bbsl-infected ticks parasitizing a bird in Canada. DNA extraction, PCR amplification, and DNA sequencing reveal that these Bbsl amplicons belong to Borrelia burgdorferi sensu stricto (Bbss), which is pathogenic to humans. Based on our findings, health-care providers should be aware that migratory songbirds widely disperse B. burgdorferi-infected I. scapularis in Canada's North, and local residents do not have to visit an endemic area to contract Lyme disease.

Persistent Borrelia Infection in Patients with Ongoing Symptoms of Lyme Disease

INTRODUCTION

Lyme disease is a tickborne illness that generates controversy among medical providers and researchers. One of the key topics of debate is the existence of persistent infection with the Lyme spirochete, Borreliaburgdorferi, in patients who have been treated with recommended doses of antibiotics yet remain symptomatic. Persistent spirochetal infection despite antibiotic therapy has recently been demonstrated in non-human primates. We present evidence of persistent Borrelia infection despite antibiotic therapy in patients with ongoing Lyme disease symptoms.

METHODS

In this pilot study, culture of body fluids and tissues was performed in a randomly selected group of 12 patients with persistent Lyme disease symptoms who had been treated or who were being treated with antibiotics. Cultures were also performed on a group of ten control subjects without Lyme disease. The cultures were subjected to corroborative microscopic, histopathological and molecular testing for Borrelia organisms in four independent laboratories in a blinded manner.

RESULTS

Motile spirochetes identified histopathologically as Borrelia were detected in culture specimens, and these spirochetes were genetically identified as Borreliaburgdorferi by three distinct polymerase chain reaction (PCR)-based approaches. Spirochetes identified as Borrelia burgdorferi were cultured from the blood of seven subjects, from the genital secretions of ten subjects, and from a skin lesion of one subject. Cultures from control subjects without Lyme disease were negative for Borrelia using these methods.

CONCLUSIONS

Using multiple corroborative detection methods, we showed that patients with persistent Lyme disease symptoms may have ongoing spirochetal infection despite antibiotic treatment, similar to findings in non-human primates. The optimal treatment for persistent Borrelia infection remains to be determined.

Co-culture of human fibroblasts and Borrelia burgdorferi enhances collagen and growth factor mRNA

Skin fibrosis has been reported in Borrelia burgdorferi infection in Europe, but has been questioned by several authors. The objective of the present study was to examine the interaction of skin fibroblasts with B. burgdorferi sensu stricto B31 (BB) and B. afzelii (BA) in vitro by electron microscopy. We also determined the expression of collagen type I, TGF-β, FGF-1, calreticulin (CALR), decorin (DCN), and PDGF-α at the mRNA level in Borrelia/fibroblast co-cultures. Intact Borrelia attach to and transmigrate fibroblasts, and undergo cystic transformation outside the fibroblasts. Fibroblasts preserve their vitality and express a prominent granular endoplasmic reticulum, suggesting activated protein synthesis. On two different semi-quantitative real-time PCR assays, BB- and BA/fibroblast co-cultures showed a significant induction of type I collagen mRNA after 2 days compared to fibroblasts (fourfold for BA and 1.8-fold for BB; p < 0.02). In addition, there was a significant upregulation of mRNA expression of TGF-β, CALR, PDGF-α, and DCN in BA and BB co-cultures compared to control fibroblasts in monolayer cultures after 2 days (p < 0.01). The BA/fibroblast co-culture induced a considerably greater upregulation of collagen and growth factor mRNA compared to BB/fibroblast co-culture. In contrast, a significant down-regulation of FGF-1 (20-fold for BA and 4.5-fold for BB) mRNA expression was detected in co-cultures compared to controls (p < 0.01). The results of the study support the hypothesis that BB sensu lato, and BA in particular, enhances collagen mRNA expression and can stimulate growth factors responsible for increased collagen production.

The Financial Implications of a Well-Hidden and Ignored Chronic Lyme Disease Pandemic

1 million people are predicted to get infected with Lyme disease in the USA in 2018. Given the same incidence rate of Lyme disease in Europe as in the USA, then 2.4 million people will get infected with Lyme disease in Europe in 2018. In the USA by 2050, 55.7 million people (12% of the population) will have been infected with Lyme disease. In Europe by 2050, 134.9 million people (17% of the population) will have been infected with Lyme disease. Most of these infections will, unfortunately, become chronic. The estimated treatment cost for acute and chronic Lyme disease for 2018 for the USA is somewhere between 4.8 billion USD and 9.6 billion USD and for Europe somewhere between 10.1 billion EUR and 20.1 billion EUR. If governments do not finance IV treatment with antibiotics for chronic Lyme disease, then the estimated government cost for chronic Lyme disease for 2018 for the USA is 10.1 billion USD and in Europe 20.1 billion EUR. If governments in the USA and Europe want to minimize future costs and maximize future revenues, then they should pay for IV antibiotic treatment up to a year even if the estimated cure rate is as low as 25%. The cost for governments of having chronic Lyme patients sick in perpetuity is very large.

Cutaneous Lyme borreliosis: Guideline of the German Dermatology Society

This guideline of the German Dermatology Society primarily focuses on the diagnosis and treatment of cutaneous manifestations of Lyme borreliosis. It has received consensus from 22 German medical societies and 2 German patient organisations. It is the first part of an AWMF (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V.) interdisciplinary guideline: “Lyme Borreliosis – Diagnosis and Treatment, development stage S3”.

The guideline is directed at physicians in private practices and clinics who treat Lyme borreliosis. Objectives of this guideline are recommendations for confirming a clinical diagnosis, recommendations for a stage-related laboratory diagnosis (serological detection of IgM and IgG Borrelia antibodies using the 2-tiered ELISA/immunoblot process, sensible use of molecular diagnostic and culture procedures) and recommendations for the treatment of the localised, early-stage infection (erythema migrans, erythema chronicum migrans, and borrelial lymphocytoma), the disseminated early-stage infection (multiple erythemata migrantia, flu-like symptoms) and treatment of the late-stage infection (acrodermatitis chronica atrophicans with and without neurological manifestations). In addition, an information sheet for patients containing recommendations for the prevention of Lyme borreliosis is attached to the guideline.

Controversies in Persistent (Chronic) Lyme Disease

The Centers for Disease Control and Prevention estimates that more than 300 000 new cases of Lyme disease occur each year in the United States and that 10% to 20% of these patients will remain symptomatic despite receiving appropriate antibiotic therapy. Many elements of the disease are poorly understood and have generated considerable controversy. This paper discusses the medical controversies related to posttreatment manifestations and their potential impact on infusion nurses.

Detection of Lyme Disease Bacterium, Borrelia burgdorferi sensu lato, in Blacklegged Ticks Collected in the Grand River Valley, Ontario, Canada

We document the presence of blacklegged ticks, Ixodes scapularis, in the Grand River valley, Centre Wellington, Ontario. Overall, 15 (36%) of 42 I. scapularis adults collected from 41 mammalian hosts (dogs, cats, humans) were positive for the Lyme disease bacterium, Borrelia burgdorferi sensu lato (s.l.). Using real-time PCR testing and DNA sequencing of the flagellin (fla) gene, we determined that Borrelia amplicons extracted from I. scapularis adults belonged to B. burgdorferi sensu stricto (s.s.), which is pathogenic to humans and certain domestic animals. Based on the distribution of I. scapularis adults within the river basin, it appears likely that migratory birds provide an annual influx of I. scapularis immatures during northward spring migration. Health-care providers need to be aware that local residents can present with Lyme disease symptoms anytime during the year.

Cardiac Tropism of Borrelia burgdorferi: An Autopsy Study of Sudden Cardiac Death Associated with Lyme Carditis

Fatal Lyme carditis caused by the spirochete Borrelia burgdorferi rarely is identified. Here, we describe the pathologic, immunohistochemical, and molecular findings of five case patients. These sudden cardiac deaths associated with Lyme carditis occurred from late summer to fall, ages ranged from young adult to late 40s, and four patients were men. Autopsy tissue samples were evaluated by light microscopy, Warthin-Starry stain, immunohistochemistry, and PCR for B. burgdorferi, and immunohistochemistry for complement components C4d and C9, CD3, CD79a, and decorin. Post-mortem blood was tested by serology. Interstitial lymphocytic pancarditis in a relatively characteristic road map distribution was present in all cases. Cardiomyocyte necrosis was minimal, T cells outnumbered B cells, plasma cells were prominent, and mild fibrosis was present. Spirochetes in the cardiac interstitium associated with collagen fibers and co-localized with decorin. Rare spirochetes were seen in the leptomeninges of two cases by immunohistochemistry. Spirochetes were not seen in other organs examined, and joint tissue was not available for evaluation. Although rare, sudden cardiac death caused by Lyme disease might be an under-recognized entity and is characterized by pancarditis and marked tropism of spirochetes for cardiac tissues.

Established Population of Blacklegged Ticks with High Infection Prevalence for the Lyme Disease Bacterium, Borrelia burgdorferi Sensu Lato, on Corkscrew Island, Kenora District, Ontario

We document an established population of blacklegged ticks, Ixodes scapularis, on Corkscrew Island, Kenora District, Ontario, Canada. Primers of the outer surface protein A (OspA) gene, the flagellin (fla) gene, and the flagellin B (flaB) gene were used in the PCR assays to detect Borrelia burgdorferi sensu lato (s.l.), the Lyme disease bacterium. In all, 60 (73%) of 82 adult I. scapularis, were infected with B. burgdorferi s.l. As well, 6 (43%) of 14 unfed I. scapularis nymphs were positive for B. burgdorferi s.l. An I. scapularis larva was also collected from a deer mouse, and several unfed larvae were gathered by flagging leaf litter. Based on DNA sequencing of randomly selected Borrelia amplicons from six nymphal and adult I. scapularis ticks, primers for the flagellin (fla) and flagellin B (flaB) genes reveal the presence of B. burgdorferi sensu stricto (s.s.), a genospecies pathogenic to humans and certain domestic animals. We collected all 3 host-feeding life stages of I. scapularis in a single year, and report the northernmost established population of I. scapularis in Ontario. Corkscrew Island is hyperendemic for Lyme disease and has the highest prevalence of B. burgdorferi s.l. for any established population in Canada. Because of this very high infection prevalence, this population of I. scapularis has likely been established for decades. Of epidemiological significance, cottage owners, island visitors, outdoors enthusiasts, and medical professionals must be vigilant that B. burgdorferi s.l.-infected I. scapularis on Corkscrew Island pose a serious public health risk.

Prevalence of the Lyme Disease Spirochete, Borrelia burgdorferi, in Blacklegged Ticks, Ixodes scapularis at Hamilton-Wentworth, Ontario

Lyme disease has emerged as a major health concern in Canada, where the etiological agent, Borrelia burgdorferi sensu lato (s.l.), a spirochetal bacterium, is typically spread by the bite of certain ticks. This study explores the presence of B. burgdorferi s.l. in blacklegged ticks, Ixodes scapularis, collected at Dundas, Ontario (a locality within the region of Hamilton-Wentworth). Using passive surveillance, veterinarians and pet groomers were asked to collect blacklegged ticks from dogs and cats with no history of travel. Additionally, I. scapularis specimens were submitted from local residents and collected by flagging. Overall, 12 (41%) of 29 blacklegged ticks were infected with B. burgdorferi s.l. Using polymerase chain reaction (PCR) and DNA sequencing, two borrelial amplicons were characterized as B. burgdorferi sensu stricto (s.s.), a genospecies pathogenic to humans and certain domestic animals. Notably, three different vertebrate hosts each had two engorged I. scapularis females removed on the same day and, likewise, one cat had three repeat occurrences of this tick species. These multiple infestations suggest that a population of I. scapularis may be established in this area. The local public health unit has been underreporting the presence of B. burgdorferi s.l.-infected I. scapularis in the area encompassing Dundas. Our findings raise concerns about the need to erect tick warning signs in parkland areas. Veterinarians, medical professionals, public health officials, and the general public must be vigilant that Lyme disease-carrying blacklegged ticks pose a public health risk in the Dundas area and the surrounding Hamilton-Wentworth region.

Borrelia burgdorferi RevA Significantly Affects Pathogenicity and Host Response in the Mouse Model of Lyme Disease

The Lyme disease spirochete, Borrelia burgdorferi, expresses RevA and numerous outer surface lipoproteins during mammalian infection. As an adhesin that promotes bacterial interaction with fibronectin, RevA is poised to interact with the extracellular matrix of the host. To further define the role(s) of RevA during mammalian infection, we created a mutant that is unable to produce RevA. The mutant was still infectious to mice, although it was significantly less well able to infect cardiac tissues. Complementation of the mutant with a wild-type revA gene restored heart infectivity to wild-type levels. Additionally, revA mutants led to increased evidence of arthritis, with increased fibrotic collagen deposition in tibiotarsal joints. The mutants also induced increased levels of the chemokine CCL2, a monocyte chemoattractant, in serum, and this increase was abolished in the complemented strain. Therefore, while revA is not absolutely essential for infection, deletion of revA had distinct effects on dissemination, arthritis severity, and host response.

Evidence assessments and guideline recommendations in Lyme disease: the clinical management of known tick bites, erythema migrans rashes and persistent disease

Evidence-based guidelines for the management of patients with Lyme disease were developed by the International Lyme and Associated Diseases Society (ILADS). The guidelines address three clinical questions - the usefulness of antibiotic prophylaxis for known tick bites, the effectiveness of erythema migrans treatment and the role of antibiotic retreatment in patients with persistent manifestations of Lyme disease. Healthcare providers who evaluate and manage patients with Lyme disease are the intended users of the new ILADS guidelines, which replace those issued in 2004 (Exp Rev Anti-infect Ther 2004;2:S1-13). These clinical practice guidelines are intended to assist clinicians by presenting evidence-based treatment recommendations, which follow the Grading of Recommendations Assessment, Development and Evaluation system. ILADS guidelines are not intended to be the sole source of guidance in managing Lyme disease and they should not be viewed as a substitute for clinical judgment nor used to establish treatment protocols.

That's my story, and I'm sticking to it--an update on B. burgdorferi adhesins

Adhesion is the initial event in the establishment of any infection. Borrelia burgdorferi, the etiological agent of Lyme disease, possesses myriad proteins termed adhesins that facilitate contact with its vertebrate hosts. B. burgdorferi adheres to host tissues through interactions with host cells and extracellular matrix, as well as other molecules present in serum and extracellular fluids. These interactions, both general and specific, are critical in the establishment of infection. Modulation of borrelial adhesion to host tissues affects the microorganisms's ability to colonize, disseminate, and persist. In this review, we update the current knowledge on structure, function, and role in pathogenesis of these “sticky” B. burgdorferi infection-associated proteins.

A systematic review of Borrelia burgdorferi morphologic variants does not support a role in chronic Lyme disease

BACKGROUND

 Much of the controversy that surrounds Lyme disease pertains to whether it produces prolonged, treatment-refractory infection, usually referred to as chronic Lyme disease. Some have proposed that round morphologic variants of Borrelia burgdorferi, known variably as "cyst forms" and "L-forms," are responsible for the pathogenesis of chronic Lyme disease. We have undertaken a systematic review of the literature to determine if there is a documented role of these variants in Lyme disease pathogenesis or in syndromes compatible with chronic Lyme disease.

METHODS

 Two systematic literature searches were performed to identify studies in which round morphologic variants of B. burgdorferi have been described in situ in human specimens.

RESULTS

 Our primary literature search identified 6 studies that reported round morphologic variants of B. burgdorferi in specimens obtained from 32 total patients. No study described these forms in patients who had purely subjective symptom complexes (eg, fatigue or pain). No study investigated a causal relationship between morphologic variants and clinical disease or evaluated treatment of morphologic variants in vivo. Of 29 additional studies that described the morphology of B. burgdorferi from patients with Lyme disease, the organism was invariably described as having spirochetal morphology.

CONCLUSIONS

 In the context of the broader medical literature, it is not currently possible to ascribe a pathogenic role to morphologic variants of B. burgdorferi in either typical manifestations of Lyme disease or in other chronic disease states that are often labeled chronic Lyme disease. There is no clinical literature to justify specific treatment of B. burgdorferi morphologic variants.

Evaluation of RevA, a fibronectin-binding protein of Borrelia burgdorferi, as a potential vaccine candidate for lyme disease

Previous studies indicated that the Lyme disease spirochete Borrelia burgdorferi expresses the RevA outer surface protein during mammalian infection. As an adhesin that promotes bacterial interaction with fibronectin, RevA appears to be a good target for preventive therapies. RevA proteins are highly conserved across all Lyme borreliae, and antibodies against RevA protein are cross-reactive among RevA proteins from diverse strains. Mice infected with B. burgdorferi mounted a rapid IgM response to RevA, followed by a strong IgG response that generally remained elevated for more than 12 months, suggesting continued exposure of RevA protein to the immune system. RevA antibodies were bactericidal in vitro. To evaluate the RevA antigen as a potential vaccine, mice were vaccinated with recombinant RevA and challenged with B. burgdorferi by inoculation with a needle or by a tick bite. Cultured tissues from all treatment groups were positive for B. burgdorferi. Vaccinated animals also appeared to have similar levels of B. burgdorferi DNA compared to nonvaccinated controls. Despite its antigenicity, surface expression, and the production of bactericidal antibodies against it, RevA does not protect against Borrelia burgdorferi infection in a mouse model. However, passive immunization with anti-RevA antibodies did prevent infection, suggesting the possible utility of RevA-based immunotherapeutics or vaccine.

Damage of collagen and elastic fibres by borrelia burgdorferi - known and new clinical and histopathological aspects

Lyme Borreliosis, or Lyme's disease, manifests itself in numerous skin conditions. Therapeutic intervention should be initiated as soon as a clinical diagnosis of erythema migrans is made. The histopathology of some of the skin conditions associated with Lyme Borreliosis is characterised by structural changes to collagen, and sometimes also elastic fibres. These conditions include morphea, lichen sclerosus et atrophicus and acrodermatitis chronica atrophicans. More recently, further skin conditions have been identified by the new microscopic investigation technique of focus floating microscopy: granuloma annulare, necrobiosis lipoidica, necrobiotic xanthogranuloma, erythema annulare centrifugum, interstitial granulomatous dermatitis, cutaneous sarcoidosis and lymphocytic infiltration; these conditions also sometimes cause changes in the connective tissue. In the case of ligaments and tendons, collagen and elastic fibres predominate structurally. They are also the structures that are targeted by Borrelia. The resultant functional disorders have previously only rarely been associated with Borreliosis in clinical practice. Ligamentopathies and tendinopathies, spontaneous ruptures of tendons after slight strain, dislocation of vertebrae and an accumulation of prolapsed intervertebral discs as well as ossification of tendon insertions can be viewed in this light.

Antibiotic retreatment of Lyme disease in patients with persistent symptoms: a biostatistical review of randomized, placebo-controlled, clinical trials

INTRODUCTION

Lyme disease (Lyme borreliosis) is caused by the tick-borne spirochete Borrelia burgdorferi. Long-term persistent illness following antibiotic treatment is not uncommon, particularly when treatment is delayed. Current treatment guidelines for persistent disease primarily rely on findings from four randomized, controlled trials (RCTs), strongly advising against retreatment.

METHODS

We performed a biostatistical review of all published RCTs evaluating antibiotic retreatment, focusing on trial design, analysis and conclusions.

RESULTS

Four RCTs met the inclusion criteria; all examined the efficacy of intravenous ceftriaxone versus placebo at approximately 3 or 6 months. Design assumptions for the primary outcomes in the two Klempner trials and two outcomes in the Krupp trial were unrealistic and the trials were likely underpowered to detect clinically meaningful treatment effects. The Klempner trials were analyzed using inefficient statistical methods. The Krupp RCT was well-designed and analyzed for fatigue, finding statistically significant and clinically meaningful improvement. Fallon corroborated this finding. Fallon also found improvement in cognitive functioning, a primary outcome, at 12 weeks which was not sustained at 24 weeks; improvements in physical functioning and pain were demonstrated at week 24 as an interaction effect between treatment and baseline symptom severity with the drug effect increasing with higher baseline impairment.

DISCUSSION

This biostatistical review reveals that retreatment can be beneficial. Primary outcomes originally reported as statistically insignificant were likely underpowered. The positive treatment effects of ceftriaxone are encouraging and consistent with continued infection, a hypothesis deserving additional study. Additional studies of persistent infection and antibiotic treatment are warranted.

ELISA-based measurement of antibody responses and PCR-based detection profiles can distinguish between active infection and early clearance of Borrelia burgdorferi

Borrelia burgdorferi is a spirochetal bacterium that causes Lyme disease. These studies address whether current research methods using either ELISA to detect seroconversion to B. burgdorferi antigens or PCR quantification of bacterial DNA within tissues can accurately distinguish between a productive infection versus a B. burgdorferi exposure that is rapidly cleared by the innate responses. Mice receiving even minimal doses of live B. burgdorferi produced significantly more B. burgdorferi-specific IgM and IgG than groups receiving large inocula of heat-killed bacteria. Additionally, sera from mice injected with varied doses of killed B. burgdorferi recognized unique borrelial antigens compared to mice infected with live B. burgdorferi. Intradermal injection of killed B. burgdorferi resulted in rapid DNA clearance from skin, whereas DNA was consistently detected in skin inoculated with viable B. burgdorferi. These data indicate that both ELISA-based serological analyses and PCR-based methods of assessing B. burgdorferi infection clearly distinguish between an established infection with live bacteria and exposure to large numbers of bacteria that are promptly cleared by the innate responses.

CD14 signaling reciprocally controls collagen deposition and turnover to regulate the development of lyme arthritis

CD14 is a glycosylphosphatidylinositol-anchored protein expressed primarily on myeloid cells (eg, neutrophils, macrophages, and dendritic cells). CD14(-/-) mice infected with Borrelia burgdorferi, the causative agent of Lyme disease, produce more proinflammatory cytokines and present with greater disease and bacterial burden in infected tissues. Recently, we uncovered a novel mechanism whereby CD14(-/-) macrophages mount a hyperinflammatory response, resulting from their inability to be tolerized by B. burgdorferi. Paradoxically, CD14 deficiency is associated with greater bacterial burden despite the presence of highly activated neutrophils and macrophages and elevated levels of cytokines with potent antimicrobial activities. Killing and clearance of Borrelia, especially in the joints, depend on the recruitment of neutrophils. Neutrophils can migrate in response to chemotactic gradients established through the action of gelatinases (eg, matrix metalloproteinase 9), which degrade collagen components of the extracellular matrix to generate tripeptide fragments of proline-glycine-proline. Using a mouse model of Lyme arthritis, we demonstrate that CD14 deficiency leads to decreased activation of matrix metalloproteinase 9, reduced degradation of collagen, and diminished recruitment of neutrophils. This reduction in neutrophil numbers is associated with greater numbers of Borrelia in infected tissues. Variation in the efficiency of neutrophil-mediated clearance of B. burgdorferi may underlie differences in the severity of Lyme arthritis observed in the patient population and suggests avenues for development of adjunctive therapy designed to augment host immunity.

Lyme disease: the next decade

Although Lyme disease remains a controversial illness, recent events have created an unprecedented opportunity to make progress against this serious tick-borne infection. Evidence presented during the legally mandated review of the restrictive Lyme guidelines of the Infectious Diseases Society of America (IDSA) has confirmed the potential for persistent infection with the Lyme spirochete, Borrelia burgdorferi, as well as the complicating role of tick-borne coinfections such as Babesia, Anaplasma, Ehrlichia, and Bartonella species associated with failure of short-course antibiotic therapy. Furthermore, renewed interest in the role of cell wall-deficient (CWD) forms in chronic bacterial infection and progress in understanding the molecular mechanisms of biofilms has focused attention on these processes in chronic Lyme disease. Recognition of the importance of CWD forms and biofilms in persistent B. burgdorferi infection should stimulate pharmaceutical research into new antimicrobial agents that target these mechanisms of chronic infection with the Lyme spirochete. Concurrent clinical implementation of proteomic screening offers a chance to correct significant deficiencies in Lyme testing. Advances in these areas have the potential to revolutionize the diagnosis and treatment of Lyme disease in the coming decade.

Treatment of Lyme borreliosis

Borrelia burgdorferi sensu lato is the causative agent of Lyme borreliosis in humans. This inflammatory disease can affect the skin, the peripheral and central nervous system, the musculoskeletal and cardiovascular system and rarely the eyes. Early stages are directly associated with viable bacteria at the site of inflammation. The pathogen-host interaction is complex and has been elucidated only in part. B. burgdorferi is highly susceptible to antibiotic treatment and the majority of patients profit from this treatment. Some patients develop chronic persistent disease despite repeated antibiotics. Whether this is a sequel of pathogen persistence or a status of chronic auto-inflammation, auto-immunity or a form of fibromyalgia is highly debated. Since vaccination is not available, prevention of a tick bite or chemoprophylaxis is important. If the infection is manifest, then treatment strategies should target not only the pathogen by using antibiotics but also the chronic inflammation by using anti-inflammatory drugs.

Ineffectiveness of tigecycline against persistent Borrelia burgdorferi

The effectiveness of a new first-in-class antibiotic, tigecycline (glycylcycline), was evaluated during the early dissemination (1 week), early immune (3 weeks), or late persistent (4 months) phases of Borrelia burgdorferi infection in C3H mice. Mice were treated with high or low doses of tigecycline, saline (negative-effect controls), or a previously published regimen of ceftriaxone (positive-effect controls). Infection status was assessed at 3 months after treatment by culture, quantitative ospA real-time PCR, and subcutaneous transplantation of joint and heart tissue into SCID mice. Tissues from all saline-treated mice were culture and ospA PCR positive, tissues from all antibiotic-treated mice were culture negative, and some of the tissues from most of the mice treated with antibiotics were ospA PCR positive, although the DNA marker load was markedly decreased compared to that in saline-treated mice. Antibiotic treatment during the early stage of infection appeared to be more effective than treatment that began during later stages of infection. The viability of noncultivable spirochetes in antibiotic-treated mice (demonstrable by PCR) was confirmed by transplantation of tissue allografts from treated mice into SCID mice, with dissemination of spirochetal DNA to multiple recipient tissues, and by xenodiagnosis, including acquisition by ticks, transmission by ticks to SCID mice, and survival through molting into nymphs and then into adults. Furthermore, PCR-positive heart base tissue from antibiotic-treated mice revealed RNA transcription of several B. burgdorferi genes. These results extended previous studies with ceftriaxone, indicating that antibiotic treatment is unable to clear persisting spirochetes, which remain viable and infectious, but are nondividing or slowly dividing.

Borrelia burgdorferi BmpA is a laminin-binding protein

The Borrelia burgdorferi BmpA outer surface protein plays a significant role in mammalian infection by the Lyme disease spirochete and is an important antigen for the serodiagnosis of human infection. B. burgdorferi adheres to host extracellular matrix components, including laminin. The results of our studies indicate that BmpA and its three paralogous proteins, BmpB, BmpC, and BmpD, all bind to mammalian laminin. BmpA did not bind mammalian type I or type IV collagens or fibronectin. BmpA-directed antibodies significantly inhibited the adherence of live B. burgdorferi to laminin. The laminin-binding domain of BmpA was mapped to the carboxy-terminal 80 amino acids. Solubilized collagen inhibited BmpA-laminin binding, suggesting interactions through the collagen-binding domains of laminin. These results, together with previous data, indicate that BmpA and its paralogs are targets for the development of preventative and curative therapies for Lyme disease.

Borrelia burgdorferi RevA antigen binds host fibronectin

Borrelia burgdorferi, the Lyme disease-causing spirochete, can persistently infect its vertebrate hosts for years. B. burgdorferi is often found associated with host connective tissue, where it interacts with components of the extracellular matrix, including fibronectin. Some years ago, a borrelial surface protein, named BBK32, was identified as a fibronectin-binding protein. However, B. burgdorferi BBK32 mutants are still able to bind fibronectin, indicating that the spirochete possesses additional mechanisms for adherence to fibronectin. We now demonstrate that RevA, an unrelated B. burgdorferi outer surface protein, binds mammalian fibronectin in a saturable manner. Site-directed mutagenesis studies identified the amino terminus of the RevA protein as being required for adhesion to fibronectin. RevA bound to the amino-terminal region of fibronectin. RevA binding to fibronectin was not inhibited by salt or heparin, suggesting that adhesin-ligand interactions are primarily nonionic and occur through the non-heparin-binding regions of the fibronectin amino-terminal domains. revA genes are widely distributed among Lyme disease spirochetes, and the present studies determined that all RevA alleles tested bound fibronectin. In addition, RevB, a paralogous protein found in a subset of B. burgdorferi strains, also bound fibronectin. We also confirmed that RevA is produced during mammalian infection but not during colonization of vector ticks and determined that revA transcription is controlled through a mechanism distinct from that of BBK32.

The Borrelia burgdorferi outer-surface protein ErpX binds mammalian laminin

The Lyme disease spirochaete, Borrelia burgdorferi, can invade and persistently infect its hosts' connective tissues. We now demonstrate that B. burgdorferi adheres to the extracellular matrix component laminin. The surface-exposed outer-membrane protein ErpX was identified as having affinity for laminin, and is the first laminin-binding protein to be identified in a Lyme disease spirochaete. The adhesive domain of ErpX was shown to be contained within a small, unstructured hydrophilic segment at the protein's centre. The sequence of that domain is distinct from any previously identified bacterial laminin adhesin, suggesting a unique mode of laminin binding.

Persistence of Borrelia burgdorferi following antibiotic treatment in mice

The effectiveness of antibiotic treatment was examined in a mouse model of Lyme borreliosis. Mice were treated with ceftriaxone or saline solution for 1 month, commencing during the early (3 weeks) or chronic (4 months) stages of infection with Borrelia burgdorferi. Tissues from mice were tested for infection by culture, PCR, xenodiagnosis, and transplantation of allografts at 1 and 3 months after completion of treatment. In addition, tissues were examined for the presence of spirochetes by immunohistochemistry. In contrast to saline solution-treated mice, mice treated with antibiotic were consistently culture negative, but tissues from some of the mice remained PCR positive, and spirochetes could be visualized in collagen-rich tissues. Furthermore, when some of the antibiotic-treated mice were fed on by Ixodes scapularis ticks (xenodiagnosis), spirochetes were acquired by the ticks, as determined based upon PCR results, and ticks from those cohorts transmitted spirochetes to naïve SCID mice, which became PCR positive but culture negative. Results indicated that following antibiotic treatment, mice remained infected with nondividing but infectious spirochetes, particularly when antibiotic treatment was commenced during the chronic stage of infection.

Lyme borreliosis spirochete Erp proteins, their known host ligands, and potential roles in mammalian infection

Lyme borreliae naturally maintain numerous distinct DNA elements of the cp32 family, each of which carries a mono- or bicistronic erp locus. The encoded Erp proteins are surface-exposed outer membrane lipoproteins that are produced at high levels during mammalian infection but largely repressed during colonization of vector ticks. Recent studies have revealed that some Erp proteins can serve as bacterial adhesins, binding host proteins such as the complement regulator factor H and the extracellular matrix component laminin. These results suggest that Erp proteins play roles in multiple aspects of mammalian infection.