Direct molecular detection and genotyping of Borrelia burgdorferi from whole blood of patients with early Lyme disease

Lyme borreliosis diagnosis: state of the art of improvements and innovations

With almost 700 000 estimated cases each year in the United States and Europe, Lyme borreliosis (LB), also called Lyme disease, is the most common tick-borne illness in the world. Transmitted by ticks of the genus Ixodes and caused by bacteria Borrelia burgdorferi sensu lato, LB occurs with various symptoms, such as erythema migrans, which is characteristic, whereas others involve blurred clinical features such as fatigue, headaches, arthralgia, and myalgia. The diagnosis of Lyme borreliosis, based on a standard two-tiered serology, is the subject of many debates and controversies, since it relies on an indirect approach which suffers from a low sensitivity depending on the stage of the disease. Above all, early detection of the disease raises some issues. Inappropriate diagnosis of Lyme borreliosis leads to therapeutic wandering, inducing potential chronic infection with a strong antibody response that fails to clear the infection. Early and proper detection of Lyme disease is essential to propose an adequate treatment to patients and avoid the persistence of the pathogen. This review presents the available tests, with an emphasis on the improvements of the current diagnosis, the innovative methods and ideas which, ultimately, will allow more precise detection of LB.

Development of a Syndromic Molecular Diagnostic Assay for Tick-Borne Pathogens Using Barcoded Magnetic Bead Technology

Infectious disease diagnostics often depend on costly serological testing with poor sensitivity, low specificity, and long turnaround time. Here, we demonstrate proof of the principle for simultaneous detection of two tick-borne pathogens from a single test sample using barcoded magnetic bead technology on the BioCode 2500 system. Specific primer sets complementary to the conserved genes of Anaplasma phagocytophilum and Borrelia burgdorferi were used in PCR amplification of the target, followed by the hybridization of the resulting biotinylated PCR products with specific probes tethered to the barcoded magnetic beads for simultaneous detection, using a fluorophore with high quantum yield. The assay has an extremely high signal to background ratio, with a limit of detection (LOD) of 2.81 50% tissue culture infection dose (TCID50)/mL and 1 CFU/mL for A. phagocytophilum and B. burgdorferi, respectively. The observed LOD for gene blocks was 1.8 copies/reaction for both the pathogens. The assay demonstrated 100% positive and negative agreement on performance evaluation using patient specimens and blood samples spiked with 1 × LOD of pathogen stock. No cross-reactivity was observed with other related tick-borne pathogens and genomic DNA of human, cattle, and canine origin. The assay can be upgraded to a sensitive and cost-effective multiplex diagnostic approach that can simultaneously detect multiple clinically important tick-borne pathogens in a single sample with a short turnaround time. IMPORTANCE The low pathogen load in the tick-borne disease test samples and the lack of highly sensitive multiplex diagnostic approaches have impacted diagnosis during clinical testing and limited surveillance studies to gauge prior insight about the prevalence of tick-borne infections in a geographical area. This article demonstrates proof of the principle for simultaneous detection of two important tick-borne pathogens from a single test sample using digital barcoded magnetic bead technology. Using a fluorophore of high quantum yield, the diagnostic approach showed high sensitivity and specificity. The LOD was 1.8 genome copies per reaction for both A. phagocytophilum and B. burgdorferi. The assay can be upgraded for the detection of all clinically important tick-borne pathogens from a single patient sample with high sensitivity and specificity. The assay can provide a diagnostic answer to the clinician in a short turnaround time to facilitate speedy therapeutic intervention to infected patients and implement public health measures to prevent community spread.

A portable immunosensor provides sensitive and rapid detection of Borrelia burgdorferi antigen in spiked blood

There are no assays for detecting B. burgdorferi antigen in blood of infected Lyme disease individuals. Here, we provide proof-of-principle evidence that we can quantify B. burgdorferi antigen in spiked blood using a portable smartphone-based fluorescence microscope that measures immunoagglutination on a paper microfluidic chip. We targeted B. burgdorferi OspA to develop a working prototype and added examples of two antigens (OspC and VlsE) that have diagnostic value for discrimination of Lyme disease stage. Using an extensively validated monoclonal antibody to OspA (LA-2), detection of OspA antigen had a broad linear range up to 100 pg/mL in 1% blood and the limit of detection (LOD) was 100 fg/mL (= 10 pg/mL in undiluted blood), which was 1000 times lower than our target of 10 ng/mL. Analysis of the two other targets was done using polyclonal and monoclonal antibodies. OspC antigen was detected at LOD 100 pg/mL (= 10 ng/mL of undiluted blood) and VlsE antigen was detected at LOD 1-10 pg/mL (= 0.1-1 ng/mL of undiluted blood). The method is accurate and was performed in 20 min from sample to answer. When optimized for detecting several B. burgdorferi antigens, this assay may differentiate active from past infections and facilitate diagnosis of Lyme disease in the initial weeks of infection, when antibody presence is typically below the threshold to be detected by serologic methods.

A diagnostic classifier for gene expression-based identification of early Lyme disease

Background

Lyme disease is a tick-borne illness that causes an estimated 476,000 infections annually in the United States. New diagnostic tests are urgently needed, as existing antibody-based assays lack sufficient sensitivity and specificity.

Methods

Here we perform transcriptome profiling by RNA sequencing (RNA-Seq), targeted RNA-Seq, and/or machine learning-based classification of 263 peripheral blood mononuclear cell samples from 218 subjects, including 94 early Lyme disease patients, 48 uninfected control subjects, and 57 patients with other infections (influenza, bacteremia, or tuberculosis). Differentially expressed genes among the 25,278 in the reference database are selected based on ≥1.5-fold change, ≤0.05 p value, and ≤0.001 false-discovery rate cutoffs. After gene selection using a k-nearest neighbor algorithm, the comparative performance of ten different classifier models is evaluated using machine learning.

Results

We identify a 31-gene Lyme disease classifier (LDC) panel that can discriminate between early Lyme patients and controls, with 23 genes (74.2%) that have previously been described in association with clinical investigations of Lyme disease patients or in vitro cell culture and rodent studies of Borrelia burgdorferi infection. Evaluation of the LDC using an independent test set of samples from 63 subjects yields an overall sensitivity of 90.0%, specificity of 100%, and accuracy of 95.2%. The LDC test is positive in 85.7% of seronegative patients and found to persist for ≥3 weeks in 9 of 12 (75%) patients.

Conclusions

These results highlight the potential clinical utility of a gene expression classifier for diagnosis of early Lyme disease, including in patients negative by conventional serologic testing.

Lyme disease is a bacterial infection spread by ticks and there are nearly half a million cases a year in the United States. However, the disease is difficult to diagnose and existing laboratory tests have limited accuracy. Here, we develop a new genetic test, described as a Lyme disease classifier (LDC), for diagnosing early Lyme disease from blood samples by assessing the patient’s response to the infection. We find that the LDC can identify early Lyme disease patients (those presenting with symptoms within weeks of a tick bite) accurately, even before standard laboratory tests turn positive. In the future, the LDC may be clinically useful as a test for Lyme disease to diagnose patients earlier in the course of their illness, thus guiding more timely and effective treatment for the infection.

Servellita et al. develop a machine learning-based classifier to diagnose Lyme disease using gene expression data. The classifier achieves high sensitivity for early infections, even prior to positivity on antibody testing.

Large-Scale Sequencing of Borreliaceae for the Construction of Pan-Genomic-Based Diagnostics

The acceleration of climate change has been associated with an alarming increase in the prevalence and geographic range of tick-borne diseases (TBD), many of which have severe and long-lasting effects-particularly when treatment is delayed principally due to inadequate diagnostics and lack of physician suspicion. Moreover, there is a paucity of treatment options for many TBDs that are complicated by diagnostic limitations for correctly identifying the offending pathogens. This review will focus on the biology, disease pathology, and detection methodologies used for the Borreliaceae family which includes the Lyme disease agent Borreliella burgdorferi. Previous work revealed that Borreliaceae genomes differ from most bacteria in that they are composed of large numbers of replicons, both linear and circular, with the main chromosome being the linear with telomeric-like termini. While these findings are novel, additional gene-specific analyses of each class of these multiple replicons are needed to better understand their respective roles in metabolism and pathogenesis of these enigmatic spirochetes. Historically, such studies were challenging due to a dearth of both analytic tools and a sufficient number of high-fidelity genomes among the various taxa within this family as a whole to provide for discriminative and functional genomic studies. Recent advances in long-read whole-genome sequencing, comparative genomics, and machine-learning have provided the tools to better understand the fundamental biology and phylogeny of these genomically-complex pathogens while also providing the data for the development of improved diagnostics and therapeutics.

Utility of Whole Blood Real-Time PCR Testing for the Diagnosis of Early Lyme Disease

OBJECTIVES

Whole blood real-time polymerase chain reaction (WB-RTPCR) detection of Borrelia burgdorferi is not currently recommended for diagnosing Lyme disease. This study aims to elucidate the utility of WB-RTPCR as a diagnostic aid for early Lyme disease (ELD), defined as either positive PCR or positive immunoglobulin M with negative immunoglobulin G immunoblot.

METHODS

A retrospective analysis was performed on 33,199 blood specimens evaluated concurrently by WB-RTPCR and antibody-capture serology (ACEIA) methods (group A). Fifty-six pairs of specimens from a separate data set were retrospectively identified and analyzed at initial and follow-up time points to monitor for seroconversion (group B). Also, a separate data set of 2,526 specimens concurrently assessed by molecular and modified two-tiered enzyme-linked immunosorbent assay serology methods was analyzed (group C).

RESULTS

Group A yielded 1,379 specimens consistent with ELD when tested by ACEIA and WB-RTPCR. In total, 131 (9.5% of positive results) were identified by WB-RTPCR, with negative serology. Group C identified 358 samples compatible with ELD, with 31 (8.7% of positive results) identified by RTPCR alone.

CONCLUSIONS

When used concurrently with serologic testing, WB-RTPCR testing increases diagnostic sensitivity in cases of ELD.

Diagnostic Testing for Lyme Disease

Standard 2-tier testing (STTT), incorporating a screening enzyme immunoassay (EIA) or an immunofluorescence assay (IFA) that reflexes to IgM and IgG immunoblots, has been the primary diagnostic test for Lyme disease since 1995. In 2019, the Food and Drug Administration approved a modified 2-tier test strategy using 2 EIAs: offering a faster, less expensive, and more sensitive assay compared with STTT. New technologies examine early immune responses to Borrelia burgdorferi have the potential to diagnose Lyme disease in the first weeks of infection when existing serologic testing is not recommended due to low sensitivity.

Capture Sequencing Enables Sensitive Detection of Tick-Borne Agents in Human Blood

Assay sensitivity can be a limiting factor in the use of PCR as a tool for the detection of tick-borne pathogens in blood. We evaluated the performance of Tick-borne disease Capture Sequencing Assay (TBDCapSeq), a capture sequencing assay targeting tick-borne agents, to test 158 whole blood specimens obtained from the Lyme Disease Biobank. These included samples from 98 individuals with signs and symptoms of acute Lyme disease, 25 healthy individuals residing in Lyme disease endemic areas, and 35 samples collected from patients admitted to the Massachusetts General Hospital or referred to the infectious disease clinic. Compared to PCR, TBDCapSeq had better sensitivity and could identify infections with a wider range of tick-borne agents. TBDCapSeq identified a higher rate of samples positive for Borrelia burgdorferi (8 vs. 1 by PCR) and Babesia microti (26 vs. 15 by PCR). TBDCapSeq also identified previously unknown infections with Borrelia miyamotoi, Ehrlichia, and Rickettsia species. Overall, TBDCapSeq identified a pathogen in 43 samples vs. 23 using PCR, with four co-infections detected versus zero by PCR. We conclude that capture sequencing enables superior detection of tick-borne agents relative to PCR.

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.

Quantitative multiplexed strategies for human Lyme disease serological testing

Lyme disease, which is primarily caused by infection with the bacterium Borrelia burgdorferi in the United States or other Borrelia species internationally, presents an ongoing challenge for diagnostics. Serological testing is the primary means of diagnosis but testing approaches differ widely, with varying degrees of sensitivity and specificity. Moreover, there is currently no reliable test to determine disease resolution following treatment. A distinct challenge in Lyme disease diagnostics is the variable patterns of human immune response to a plurality of antigens presented by Borrelia spp. during the infection. Thus, multiplexed testing approaches that capture these patterns and detect serological response against multiple antigens may be the key to prompt, accurate Lyme disease diagnosis. In this review, current state-of-the-art multiplexed diagnostic approaches are presented and compared with respect to their diagnostic accuracy and their potential for monitoring response to treatment.

Clinical chorioamnionitis at term X: microbiology, clinical signs, placental pathology, and neonatal bacteremia - implications for clinical care

OBJECTIVES

Clinical chorioamnionitis at term is considered the most common infection-related diagnosis in labor and delivery units worldwide. The syndrome affects 5-12% of all term pregnancies and is a leading cause of maternal morbidity and mortality as well as neonatal death and sepsis. The objectives of this study were to determine the (1) amniotic fluid microbiology using cultivation and molecular microbiologic techniques; (2) diagnostic accuracy of the clinical criteria used to identify patients with intra-amniotic infection; (3) relationship between acute inflammatory lesions of the placenta (maternal and fetal inflammatory responses) and amniotic fluid microbiology and inflammatory markers; and (4) frequency of neonatal bacteremia.

METHODS

This retrospective cross-sectional study included 43 women with the diagnosis of clinical chorioamnionitis at term. The presence of microorganisms in the amniotic cavity was determined through the analysis of amniotic fluid samples by cultivation for aerobes, anaerobes, and genital mycoplasmas. A broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry was also used to detect bacteria, select viruses, and fungi. Intra-amniotic inflammation was defined as an elevated amniotic fluid interleukin-6 (IL-6) concentration ≥2.6 ng/mL.

RESULTS

(1) Intra-amniotic infection (defined as the combination of microorganisms detected in amniotic fluid and an elevated IL-6 concentration) was present in 63% (27/43) of cases; (2) the most common microorganisms found in the amniotic fluid samples were Ureaplasma species, followed by Gardnerella vaginalis; (3) sterile intra-amniotic inflammation (elevated IL-6 in amniotic fluid but without detectable microorganisms) was present in 5% (2/43) of cases; (4) 26% of patients with the diagnosis of clinical chorioamnionitis had no evidence of intra-amniotic infection or intra-amniotic inflammation; (5) intra-amniotic infection was more common when the membranes were ruptured than when they were intact (78% [21/27] vs. 38% [6/16]; p=0.01); (6) the traditional criteria for the diagnosis of clinical chorioamnionitis had poor diagnostic performance in identifying proven intra-amniotic infection (overall accuracy, 40-58%); (7) neonatal bacteremia was diagnosed in 4.9% (2/41) of cases; and (8) a fetal inflammatory response defined as the presence of severe acute funisitis was observed in 33% (9/27) of cases.

CONCLUSIONS

Clinical chorioamnionitis at term, a syndrome that can result from intra-amniotic infection, was diagnosed in approximately 63% of cases and sterile intra-amniotic inflammation in 5% of cases. However, a substantial number of patients had no evidence of intra-amniotic infection or intra-amniotic inflammation. Evidence of the fetal inflammatory response syndrome was frequently present, but microorganisms were detected in only 4.9% of cases based on cultures of aerobic and anaerobic bacteria in neonatal blood.

Predicting Lyme Disease From Patients' Peripheral Blood Mononuclear Cells Profiled With RNA-Sequencing

Although widely prevalent, Lyme disease is still under-diagnosed and misunderstood. Here we followed 73 acute Lyme disease patients and uninfected controls over a period of a year. At each visit, RNA-sequencing was applied to profile patients' peripheral blood mononuclear cells in addition to extensive clinical phenotyping. Based on the projection of the RNA-seq data into lower dimensions, we observe that the cases are separated from controls, and almost all cases never return to cluster with the controls over time. Enrichment analysis of the differentially expressed genes between clusters identifies up-regulation of immune response genes. This observation is also supported by deconvolution analysis to identify the changes in cell type composition due to Lyme disease infection. Importantly, we developed several machine learning classifiers that attempt to perform various Lyme disease classifications. We show that Lyme patients can be distinguished from the controls as well as from COVID-19 patients, but classification was not successful in distinguishing those patients with early Lyme disease cases that would advance to develop post-treatment persistent symptoms.

Arthritis and Diagnostics in Lyme Disease

The diagnosis of Lyme disease, caused by Borrelia burgdorferi, is clinical but frequently supported by laboratory tests. Lyme arthritis is now less frequently seen than at the time of its discovery. However, it still occurs, and it is important to recognize this, the differential diagnoses, and how laboratory tests can be useful and their limitations. The most frequently used diagnostic tests are antibody based. However, antibody testing still suffers from many drawbacks and is only an indirect measure of exposure. In contrast, evolving direct diagnostic methods can indicate active infection.

Laboratory Diagnosis of Lyme Borreliosis

Lyme borreliosis is caused by a growing list of related, yet distinct, spirochetes with complex biology and sophisticated immune evasion mechanisms. It may result in a range of clinical manifestations involving different organ systems, and can lead to persistent sequelae in a subset of cases. The pathogenesis of Lyme borreliosis is incompletely understood, and laboratory diagnosis, the focus of this review, requires considerable understanding to interpret the results correctly. Direct detection of the infectious agent is usually not possible or practical, necessitating a continued reliance on serologic testing. Still, some important advances have been made in the area of diagnostics, and there are many promising ideas for future assay development. This review summarizes the state of the art in laboratory diagnostics for Lyme borreliosis, provides guidance in test selection and interpretation, and highlights future directions.

Tick-borne zoonoses and commonly used diagnostic methods in human and veterinary medicine

Around the world, human health and animal health are closely linked in terms of the One Health concept by ticks acting as vectors for zoonotic pathogens. Animals do not only maintain tick cycles but can either be clinically affected by the same tick-borne pathogens as humans and/or play a role as reservoirs or sentinel pathogen hosts. However, the relevance of different tick-borne diseases (TBDs) may vary in human vs. veterinary medicine, which is consequently reflected by the availability of human vs. veterinary diagnostic tests. Yet, as TBDs gain importance in both fields and rare zoonotic pathogens, such as Babesia spp., are increasingly identified as causes of human disease, a One Health approach regarding development of new diagnostic tools may lead to synergistic benefits. This review gives an overview on zoonotic protozoan, bacterial and viral tick-borne pathogens worldwide, discusses commonly used diagnostic techniques for TBDs, and compares commercial availability of diagnostic tests for humans vs. domestic animals, using Germany as an example, with the aim of highlighting existing gaps and opportunities for collaboration in a One Health framework.

Molecular Microbiological and Immune Characterization of a Cohort of Patients Diagnosed with Early Lyme Disease

Lyme disease is a tick-borne infection caused by the bacteria Borrelia burgdorferi Current diagnosis of early Lyme disease relies heavily on clinical criteria, including the presence of an erythema migrans rash. The sensitivity of current gold-standard diagnostic tests relies upon antibody formation, which is typically delayed and thus of limited utility in early infection. We conducted a study of blood and skin biopsy specimens from 57 patients with a clinical diagnosis of erythema migrans. Samples collected at the time of diagnosis were analyzed using an ultrasensitive, PCR-based assay employing an isothermal amplification step and multiple primers. In 75.4% of patients, we directly detected one or more B. burgdorferi genotypes in the skin. Two-tier testing showed that 20 (46.5%) of those found to be PCR positive remained serologically negative at both acute and convalescent time points. Multiple genotypes were found in three (8%) of those where a specific genotype could be identified. The 13 participants who lacked PCR and serologic evidence for exposure to B. burgdorferi could be differentiated as a group from PCR-positive participants by their levels of several immune markers as well as by clinical descriptors such as the number of acute symptoms and the pattern of their erythema migrans rash. These results suggest that within a Mid-Atlantic cohort, patient subgroups can be identified using PCR-based direct detection approaches. This may be particularly useful in future research such as vaccine trials and public health surveillance of tick-borne disease patterns.

Development of a sensitive molecular diagnostic assay for detecting Borrelia burgdorferi DNA from the blood of Lyme disease patients by digital PCR

Lyme disease patients would greatly benefit from a timely, sensitive, and specific molecular diagnostic test that can detect the causal agent Borrelia burgdorferi at the onset of symptoms. Currently available diagnostic methods recommended by the Centers for Disease Control and Prevention for Lyme disease involve indirect serological tests that rely on the detection of a host-antibody response, which often takes more than three weeks to develop. With this process, many positive cases are not detected within a timely manner, preventing a complete cure. In this study, we have developed a digital polymerase chain reaction (PCR) assay that detects Lyme disease on clinical presentation with a sensitivity two-fold higher than that of the currently available diagnostic methods, using a cohort of patient samples collected from the Lyme disease endemic state of Connecticut, USA, in 2016-2018. Digital PCR technology was chosen as it is more advanced and sensitive than other PCR techniques in detecting rare targets. The analytical detection sensitivity of this diagnostic assay is approximately three genome copies of B. burgdorferi. The paucity of spirochetes in the bloodstream of Lyme disease patients has hindered the clinical adoption of PCR-based diagnostic tests. However, this drawback was overcome by using a comparatively larger sample volume, applying pre-analytical processing to the blood samples, and implementing a pre-amplification step to enrich for B. burgdorferi-specific gene targets before the patient samples are analyzed via digital PCR technology. Pre-analytical processing of blood samples from acute patients revealed that the best sample type for Lyme disease detection is platelet-rich plasma rather than whole blood. If detected in a timely manner, Lyme disease can be completely cured, thus limiting antibiotic overuse and associated morbidities.

Seroprevalence of Borrelia burgdorferi in Stray Dogs from Southern Italy

Borrelia burgdorferi is a bacterial pathogen transmitted by Ixodes ticks and is responsible for Lyme disease in both humans and dogs. The aim of this work was to evaluate B. burgdorferi diffusion among stray dogs in Palermo (Sicily, Italy) by serological methods in order to study the risk factors associated with the infection. Serum and blood samples of 316 dogs were collected from a shelter in Palermo, and were analyzed for the presence of antibodies against B. burgdorferi by indirect immunofluorescence assay (IFA), and of the ospA gene by real-time PCR, respectively. Seventeen sera (5.4%) were positive for the antibodies via IFA and one blood (0.3%) for ospA via real time PCR. On the basis of serological results, the evaluation of the potential risk factors (sex, age, breed and coat color) was carried out. The multivariate analysis indicated that male sex is a factor significantly associated with B. burgdorferi seropositivity. This study confirms that male dogs have a higher risk of developing the disease than females, and represents the first investigation on the spread of B. burgdorferi among stray dogs in Sicily.

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.

Preterm labor is characterized by a high abundance of amniotic fluid prostaglandins in patients with intra-amniotic infection or sterile intra-amniotic inflammation

Objective: To distinguish between prostaglandin and prostamide concentrations in the amniotic fluid of women who had an episode of preterm labor with intact membranes through the utilisation of liquid chromatography-tandem mass spectrometry.Study design: Liquid chromatography-tandem mass spectrometry analysis of amniotic fluid of women with preterm labor and (1) subsequent delivery at term (2) preterm delivery without intra-amniotic inflammation; (3) preterm delivery with sterile intra-amniotic inflammation (interleukin (IL)-6>2.6 ng/mL without detectable microorganisms); and (4) preterm delivery with intra-amniotic infection [IL-6>2.6 ng/mL with detectable microorganisms].Results: (1) amniotic fluid concentrations of PGE₂, PGF_2α, and PGFM were higher in patients with intra-amniotic infection than in those without intra-amniotic inflammation; (2) PGE₂ and PGF_2α concentrations were also greater in patients with intra-amniotic infection than in those with sterile intra-amniotic inflammation; (3) patients with sterile intra-amniotic inflammation had higher amniotic fluid concentrations of PGE₂ and PGFM than those without intra-amniotic inflammation who delivered at term; (4) PGFM concentrations were also greater in women with sterile intra-amniotic inflammation than in those without intra-amniotic inflammation who delivered preterm; (5) amniotic fluid concentrations of prostamides (PGE₂-EA and PGF_2α-EA) were not different among patients with preterm labor; (6) amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in cases with intra-amniotic inflammation; and (7) the PGE₂:PGE₂-EA and PGF_2α:PGF_2α-EA ratios were higher in patients with intra-amniotic infection compared to those without inflammation.Conclusions: Mass spectrometric analysis of amniotic fluid indicated that amniotic fluid concentrations of prostaglandins, but no prostamides, were higher in women with preterm labor and intra-amniotic infection than in other patients with an episode of preterm labor. Yet, women with intra-amniotic infection had greater amniotic fluid concentrations of PGE₂ and PGF_2α than those with sterile intra-amniotic inflammation, suggesting that these two clinical conditions may be differentiated by using mass spectrometric analysis of amniotic fluid.

Lyme Disease Frontiers: Reconciling Borrelia Biology and Clinical Conundrums

Lyme disease is a complex tick-borne zoonosis that poses an escalating public health threat in several parts of the world, despite sophisticated healthcare infrastructure and decades of effort to address the problem. Concepts like the true burden of the illness, from incidence rates to longstanding consequences of infection, and optimal case management, also remain shrouded in controversy. At the heart of this multidisciplinary issue are the causative spirochetal pathogens belonging to the Borrelia Lyme complex. Their unusual physiology and versatile lifestyle have challenged microbiologists, and may also hold the key to unlocking mysteries of the disease. The goal of this review is therefore to integrate established and emerging concepts of Borrelia biology and pathogenesis, and position them in the broader context of biomedical research and clinical practice. We begin by considering the conventions around diagnosing and characterizing Lyme disease that have served as a conceptual framework for the discipline. We then explore virulence from the perspective of both host (genetic and environmental predispositions) and pathogen (serotypes, dissemination, and immune modulation), as well as considering antimicrobial strategies (lab methodology, resistance, persistence, and clinical application), and borrelial adaptations of hypothesized medical significance (phenotypic plasticity or pleomorphy).

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.

Molecular Testing of Serial Blood Specimens from Patients with Early Lyme Disease during Treatment Reveals Changing Coinfection with Mixtures of Borrelia burgdorferi Genotypes

Borrelia burgdorferi is the etiological agent of Lyme disease. In the current study, we used direct-detection PCR and electrospray ionization mass spectrometry to monitor and genotype B. burgdorferi isolates from serially collected whole-blood specimens from patients clinically diagnosed with early Lyme disease before and during 21 days of antibiotic therapy. B. burgdorferi isolates were detected up to 3 weeks after the initiation of antibiotic treatment, with ratios of coinfecting B. burgdorferi genotypes changing over time.

Direct Diagnostic Tests for Lyme Disease

Borrelia burgdorferi was discovered to be the cause of Lyme disease in 1983, leading to seroassays. The 1994 serodiagnostic testing guidelines predated a full understanding of key B. burgdorferi antigens and have a number of shortcomings. These serologic tests cannot distinguish active infection, past infection, or reinfection. Reliable direct-detection methods for active B. burgdorferi infection have been lacking in the past but are needed and appear achievable. New approaches have effectively been applied to other emerging infections and show promise in direct detection of B. burgdorferi infections.

Recent strategies for the diagnosis of early Lyme disease

Lyme disease (LD) is the most common tick-borne disease in the Northern Hemisphere. As the most prevalent vector-borne disease in the USA, LD affects 300,000 human cases each year. LD is caused by inoculation of the bacterial spirochete, Borrelia burgdorferi sensu lato, from an infected tick. If not treated quickly and completely, the bacteria disseminate from the tick's biting site into multiple organs including the joints, heart, and brain. Thus, the best outcome from medical intervention can be expected with early detection and treatment with antibiotics, prior to multi-organ dissemination. In the absence of a characteristic rash, LD is diagnosed using serological testing involving enzyme-linked immunosorbent assay (ELISA) followed by western blotting, which is collectively known as the two-tier algorithm. These assays detect host antibodies against the bacteria, but are hampered by low sensitivity, which can miss early LD cases. This review discusses the application of some current assays for diagnosing LD clinically, thus providing a foundation for exploring newer techniques being developed in the laboratory for more sensitive detection of early LD.

Xenodiagnosis Using Ixodes scapularis Larval Ticks in Humans

Xenodiagnosis is the use of a natural vector to detect the presence of an organism, and xenodiagnosis using Ixodes ticks has long been used by entomologists in Lyme disease research to provide evidence of the host's infectious status with Borrelia burgdorferi. We developed the methodology and performed the first human research study using uninfected larval Ixodes scapularis ticks to assess evidence of B. burgdorferi infection. Here, we describe in detail the methodology used for the procedure. Xenodiagnosis using Ixodes ticks in humans remains an experimental method and must be performed under an approved clinical research protocol.

Laboratory diagnosis of Lyme borreliosis: Current state of the art and future perspectives

This review is directed at physicians and laboratory personnel in private practice and clinics who treat and diagnose Lyme borreliosis (LB) in patients as part of their daily work. A major objective of this paper is to bring together background information on Borrelia (B.) burgdorferi sensu lato (s.l.) and basic clinical knowledge of LB, which is one of the most frequently reported vector-borne diseases in the Northern Hemisphere. The goal is to provide practical guidance for clinicians and for laboratory physicians, and scientists for a better understanding of current achievements and ongoing obstacles in the laboratory diagnosis of LB, an infectious disease that still remains one of the diagnostic chameleons of modern clinical medicine. Moreover, in bringing together current scientific information from guidelines, reviews, and original papers, this review provides recommendations for selecting the appropriate tests in relation to the patient's stage of disease to achieve effective, stage-related application of current direct and indirect laboratory methods for the detection of B. burgdorferi s.l. Additionally, the review aims to discuss the current state of the art concerning the diagnostic potential and limitations of the assays and test methods currently in use to optimize LB patient management and provide insight into the possible future prospects of this rapidly changing area of laboratory medicine.

Broad-range survey of vector-borne pathogens and tick host identification of Ixodes ricinus from Southern Czech Republic

Ixodes ricinus ticks are vectors of numerous human and animal pathogens. They are host generalists able to feed on more than 300 vertebrate species. The prevalence of tick-borne pathogens is influenced by host-vector-pathogen interactions that results in spatial distribution of infection risk. Broad-range polymerase chain reaction electrospray ionization mass spectrometry (PCR/ESI-MS) was used to analyze 435 I. ricinus nymphs from four localities in the south of the Czech Republic for the species identification of tick-borne pathogens. Borrelia burgdorferi sensu lato spirochetes were the most common pathogen detected in the ticks; 21% of ticks were positive for a single genospecies and 2% were co-infected with two genospecies. Other tick-borne pathogens detected included Rickettsia helvetica (3.9%), R. monacensis (0.2%), Anaplasma phagocytophilum (2.8%), Babesia venatorum (0.9%), and Ba. microti (0.5%). The vertebrate host of the ticks was determined using PCR followed by reverse line blot hybridization from the tick's blood-meal remnants. The host was identified for 61% of ticks. DNA of two hosts was detected in 16% of samples with successful host identification. The majority of ticks had fed on artiodactyls (50.7%) followed by rodents (28.6%) and birds (7.8%). Other host species were wild boar, deer, squirrels, field mice and voles.

Diagnosing Borreliosis

Borrelia species fall into two groups, the Borrelia burgdorferi sensu lato (Bbsl) complex, the cause of Lyme borreliosis (also known as Lyme disease), and the relapsing fever group. Both groups exhibit inter- and intraspecies diversity and thus have variations in both clinical presentation and diagnostic approaches. A further layer of complexity is derived from the fact that ticks may carry multiple infectious agents and are able to transmit them to the host during blood feeding, with potential overlapping clinical manifestations. Besides this, pathogens like Borrelia have developed strategies to evade the host immune system, which allows them to persist within the host, including humans. Diagnostics can be applied at different times during the clinical course and utilize sample types, each with their own advantages and limitations. These differing methods should always be considered in conjunction with potential exposure and compatible clinical features. Throughout this review, we aim to explore different approaches providing the reader with an overview of methods appropriate for various situations. This review will cover human pathogenic members of Bbsl and relapsing fever borreliae, including newly recognized Borrelia miyamotoi spirochetes.

T2 Magnetic Resonance Assay-Based Direct Detection of Three Lyme Disease-Related Borrelia Species in Whole-Blood Samples

In early Lyme disease (LD), serologic testing is insensitive and seroreactivity may reflect active or past infection. In this study, we evaluated a novel assay for the direct detection of three species of Borrelia spirochetes in whole blood. The T2 magnetic resonance (T2MR) assay platform was used to amplify Borrelia DNA released from intact spirochetes and to detect amplicon. Analytical sensitivity was determined from blood spiked with known concentrations of spirochetes, and the assay's limit of detection was found to be in the single-cell-per-milliliter range: 5 cells/ml for B. afzelii and 8 cells/ml for Borrelia burgdorferi and Borrelia garinii Clinical samples (n = 66) from confirmed or suspected early LD patients were also analyzed. B. burgdorferi was detected using T2MR in 2/2 (100%) of blood samples from patients with confirmed early LD, based on the presence of erythema migrans and documentation of seroconversion or a positive real-time blood PCR. T2MR detected B. burgdorferi in blood samples from 17/54 (31%) of patients with probable LD, based on the presence of erythema migrans without documented seroconversion or of documented seroconversion in patients with a compatible clinical syndrome but without erythema migrans. Out of 21 clinical samples tested by real-time PCR, only 1 was positive and 13 were negative with agreement with T2MR. An additional 7 samples that were negative by real-time PCR were positive with T2MR. Therefore, T2MR enables a low limit of detection (LoD) for Borrelia spp. in whole blood samples and is able to detect B. burgdorferi in clinical samples.

The Challenges and Advances in Diagnosis of Vector-Borne Diseases: Where Do We Stand?

Vector-borne diseases (VBD) are of major importance to human and animal health. In recent years, VBD have been emerging or re-emerging in many geographical areas, alarming new disease threats and economic losses. The precise diagnosis of many of these diseases still remains a major challenge because of the lack of comprehensive data available on accurate and reliable diagnostic methods. Here, we conducted a systematic and in-depth review of the former, current, and upcoming techniques employed for the diagnosis of VBD.

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.

Progress in the molecular diagnosis of Lyme disease

INTRODUCTION

Current laboratory testing of Lyme borreliosis mostly relies on serological methods with known limitations. Diagnostic modalities enabling direct detection of pathogen at the onset of the clinical signs could overcome some of the limitations. Molecular methods detecting borrelial DNA seem to be the ideal solution, although there are some aspects that need to be considered. Areas covered: This review represent summary and discussion of the published data obtained from literature searches from PubMed and The National Library of Medicine (USA) together with our own experience on molecular diagnosis of Lyme disease. Expert commentary: Molecular methods are promising and currently serve as supporting diagnostic testing in Lyme borreliosis. Since the field of molecular diagnostics is under rapid development, molecular testing could become an important diagnostic modality.

Commercial test kits for detection of Lyme borreliosis: a meta-analysis of test accuracy

The clinical diagnosis of Lyme borreliosis can be supported by various test methodologies; test kits are available from many manufacturers. Literature searches were carried out to identify studies that reported characteristics of the test kits. Of 50 searched studies, 18 were included where the tests were commercially available and samples were proven to be positive using serology testing, evidence of an erythema migrans rash, and/or culture. Additional requirements were a test specificity of ≥85% and publication in the last 20 years. The weighted mean sensitivity for all tests and for all samples was 59.5%. Individual study means varied from 30.6% to 86.2%. Sensitivity for each test technology varied from 62.4% for Western blot kits, and 62.3% for enzyme-linked immunosorbent assay tests, to 53.9% for synthetic C6 peptide ELISA tests and 53.7% when the two-tier methodology was used. Test sensitivity increased as dissemination of the pathogen affected different organs; however, the absence of data on the time from infection to serological testing and the lack of standard definitions for “early” and “late” disease prevented analysis of test sensitivity versus time of infection. The lack of standardization of the definitions of disease stage and the possibility of retrospective selection bias prevented clear evaluation of test sensitivity by “stage”. The sensitivity for samples classified as acute disease was 35.4%, with a corresponding sensitivity of 64.5% for samples from patients defined as convalescent. Regression analysis demonstrated an improvement of 4% in test sensitivity over the 20-year study period. The studies did not provide data to indicate the sensitivity of tests used in a clinical setting since the effect of recent use of antibiotics or steroids or other factors affecting antibody response was not factored in. The tests were developed for only specific Borrelia species; sensitivities for other species could not be calculated.

Lipidomic analysis of patients with microbial invasion of the amniotic cavity reveals up-regulation of leukotriene B4

Bioactive lipids derived from the metabolism of polyunsaturated fatty acids are important mediators of the inflammatory response. Labor per se is considered a sterile inflammatory process. Intra-amniotic inflammation (IAI) due to microorganisms (i.e., intra-amniotic infection) or danger signals (i.e., sterile IAI) has been implicated in the pathogenesis of preterm labor and clinical chorioamnionitis at term. Early and accurate diagnosis of microbial invasion of the amniotic cavity (MIAC) requires analysis of amniotic fluid (AF). It is possible that IAI caused by microorganisms is associated with a stereotypic lipidomic profile, and that analysis of AF may help in the identification of patients with this condition. To test this hypothesis, we analyzed the fatty acyl lipidome of AF by liquid chromatography-mass spectrometry from patients in spontaneous labor at term and preterm gestations. We report that the AF concentrations of proinflammatory lipid mediators of the 5-lipoxygenase pathway are significantly higher in MIAC than in cases of sterile IAI. These results suggest that the concentrations of 5-lipoxygenase metabolites of arachidonic acid, 5-hydroxyeicosatetraenoic acid, and leukotriene B4 in particular could serve as potential biomarkers of MIAC. This finding could have important implications for the rapid identification of patients who may benefit from anti-microbial treatment.-Maddipati, K. R., Romero, R., Chaiworapongsa ,T., Chaemsaithong, P., Zhou, S.-L., Xu, Z., Tarca, A. L., Kusanovic, J. P., Gomez, R., Chaiyasit, N., Honn, K. V. Lipidomic analysis of patients with microbial invasion of the amniotic cavity reveals up-regulation of leukotriene B4.

CCL19 as a Chemokine Risk Factor for Posttreatment Lyme Disease Syndrome: a Prospective Clinical Cohort Study

Approximately 10% to 20% of patients optimally treated for early Lyme disease develop persistent symptoms of unknown pathophysiology termed posttreatment Lyme disease syndrome (PTLDS). The objective of this study was to investigate associations between PTLDS and immune mediator levels during acute illness and at several time points following treatment. Seventy-six participants with physician-documented erythema migrans and 26 healthy controls with no history of Lyme disease were enrolled. Sixty-four cytokines, chemokines, and inflammatory markers were measured at each visit for a total of 6 visits over 1 year. An operationalized definition of PTLDS incorporating symptoms and functional impact was applied at 6 months and 1 year following treatment completion, and clinical outcome groups were defined as the return-to-health, symptoms-only, and PTLDS groups. Significance analysis of microarrays identified 7 of the 64 immune mediators to be differentially regulated by group. Generalized logit regressions controlling for potential confounders identified posttreatment levels of the T-cell chemokine CCL19 to be independently associated with clinical outcome group. Receiver operating characteristic analysis identified a CCL19 cutoff of >111.67 pg/ml at 1 month following treatment completion to be 82% sensitive and 83% specific for later PTLDS. We speculate that persistently elevated CCL19 levels among participants with PTLDS may reflect ongoing, immune-driven reactions at sites distal to secondary lymphoid tissue. Our findings suggest the relevance of CCL19 both during acute infection and as an immunologic risk factor for PTLDS during the posttreatment phase. Identification of a potential biomarker predictor for PTLDS provides the opportunity to better understand its pathophysiology and to develop early interventions in the context of appropriate and specific clinical information.

Clinical chorioamnionitis at term: the amniotic fluid fatty acyl lipidome

Clinical chorioamnionitis at term (TCC) is the most common obstetrical infliction diagnosed in labor and delivery units worldwide and is associated with a substantial increase in maternal and neonatal morbidity and mortality. This obstetrical complication is a heterogeneous condition, as only half of patients have detectable microorganisms in the amniotic cavity. Because bioactive lipids play a key role in the initiation and resolution of an inflammatory response, we aimed to characterize the amniotic fluid lipidome in patients with TCC. We studied the amniotic fluid of patients in the following groups: 1) spontaneous labor at term without clinical chorioamnionitis (TLB) and 2) spontaneous labor at term with clinical chorioamnionitis (TCC). The TCC group was subdivided into a) those with microbial invasion of the amniotic cavity (TCC-MIAC) and b) those without microbial invasion of the amniotic cavity (TCC-noMIAC). The amniotic fluid concentration of proinflammatory lipid mediators did not differ between patients in TLB with TCC. In contrast, concentration of lipids with anti-inflammatory/proresolution properties was significantly lower in all patients with TCC than in those with TLB. These results suggest that while proinflammatory lipid mediators are involved in infection-driven intra-amniotic inflammation, a relative deficiency of anti-inflammatory/proresolution lipid mediator biosynthesis is a characteristic of TCC.

Five-Antigen Fluorescent Bead-Based Assay for Diagnosis of Lyme Disease

The systematically difficult task of diagnosing Lyme disease can be simplified by sensitive and specific laboratory tests. The currently recommended two-tier test for serology is highly specific but falls short in sensitivity, especially in the early acute phase. We previously examined serially collected serum samples from Borrelia burgdorferi-infected rhesus macaques and defined a combination of antigens that could be utilized for detection of infection at all phases of disease in humans. The five B. burgdorferi antigens, consisting of OspC, OspA, DbpA, OppA2, and the C6 peptide, were combined into a fluorescent cytometric bead-based assay for the detection of B. burgdorferi antigen-specific IgG antibodies. Samples from Lyme disease patients and controls were used to determine the diagnostic value of this assay. Using this sample set, we found that our five-antigen multiplex IgG assay exhibited higher sensitivity (79.5%) than the enzyme immunoassay (EIA) (76.1%), the two-tier test (61.4%), and the C6 peptide enzyme-linked immunosorbent assay (ELISA) (77.2%) while maintaining specificity over 90%. When detection of IgM was added to the bead-based assay, the sensitivity improved to 91%, but at a cost of reduced specificity (78%). These results indicate that the rational combination of antigens in our multiplex assay may offer an improved serodiagnostic test for Lyme disease.

Laboratory diagnosis of Lyme disease: advances and challenges

The majority of laboratory tests performed for the diagnosis of Lyme disease are based on detection of the antibody responses against B burgdorferi in serum. The sensitivity of antibody-based tests increases with the duration of the infection. Patients early in their illness are more likely to have a negative result. There is a need to simplify the testing algorithm for Lyme disease, improving sensitivity in early disease while still maintaining high specificity and providing information about the stage of infection. The development of a point of care assay and biomarkers for active infection would be major advances for the field.

Quantification of Borrelia burgdorferi Membrane Proteins in Human Serum: A New Concept for Detection of Bacterial Infection

The Borrelia burgdorferi spirochete is the causative agent of Lyme disease, the most common tick-borne disease in the United States. The low abundance of bacterial proteins in human serum during infection imposes a challenge for early proteomic detection of Lyme disease. To address this challenge, we propose to detect membrane proteins released from bacteria due to disruption of their plasma membrane triggered by the innate immune system. These membrane proteins can be separated from the bulk of serum proteins by high-speed centrifugation causing substantial sample enrichment prior to targeted protein quantification using multiple reaction monitoring mass spectrometry. This new approach was first applied to detection of B. burgdorferi membrane proteins supplemented in human serum. Our results indicated that detection of B. burgdorferi membrane proteins, which are ≈10(7) lower in abundance than major serum proteins, is feasible. Therefore, quantitative analysis was also carried out for serum samples from three patients with acute Lyme disease. We were able to demonstrate the detection of ospA, the major B. burgdorferi lipoprotein at the level of 4.0 fmol of ospA/mg of serum protein. The results confirm the concept and suggest that the proposed approach can be expanded to detect other bacterial infections in humans, particularly where existing diagnostics are unreliable.

Broad-range survey of tick-borne pathogens in Southern Germany reveals a high prevalence of Babesia microti and a diversity of other tick-borne pathogens

Abstract Ticks harbor numerous pathogens of significance to human and animal health. A better understanding of the pathogens carried by ticks in a given geographic area can alert health care providers of specific health risks leading to better diagnosis and treatments. In this study, we tested 226 Ixodes ricinis ticks from Southern Germany using a broad-range PCR and electrospray ionization mass spectrometry assay (PCR/ESI-MS) designed to identify tick-borne bacterial and protozoan pathogens in a single test. We found 21.2% of the ticks tested carried Borrelia burgdorferi sensu lato consisting of diverse genospecies; a surprisingly high percentage of ticks were infected with Babesia microti (3.5%). Other organisms found included Borrelia miyamotoi, Rickettsia helvetica, Rickettsia monacensis, and Anaplasma phagocytophilum. Of further significance was our finding that more than 7% of ticks were infected with more than one pathogen or putative pathogen.

Survey of Ixodes pacificus Ticks in California Reveals a Diversity of Microorganisms and a Novel and Widespread Anaplasmataceae Species

Ixodes pacificus ticks can harbor a wide range of human and animal pathogens. To survey the prevalence of tick-borne known and putative pathogens, we tested 982 individual adult and nymphal I. pacificus ticks collected throughout California between 2007 and 2009 using a broad-range PCR and electrospray ionization mass spectrometry (PCR/ESI-MS) assay designed to detect a wide range of tick-borne microorganisms. Overall, 1.4% of the ticks were found to be infected with Borrelia burgdorferi, 2.0% were infected with Borrelia miyamotoi and 0.3% were infected with Anaplasma phagocytophilum. In addition, 3.0% were infected with Babesia odocoilei. About 1.2% of the ticks were co-infected with more than one pathogen or putative pathogen. In addition, we identified a novel Anaplasmataceae species that we characterized by sequencing of its 16S rRNA, groEL, gltA, and rpoB genes. Sequence analysis indicated that this organism is phylogenetically distinct from known Anaplasma species with its closest genetic near neighbors coming from Asia. The prevalence of this novel Anaplasmataceae species was as high as 21% at one site, and it was detected in 4.9% of ticks tested statewide. Based upon this genetic characterization we propose that this organism be called ‘Candidatus Cryptoplasma californiense’. Knowledge of this novel microbe will provide awareness for the community about the breadth of the I. pacificus microbiome, the concept that this bacterium could be more widely spread; and an opportunity to explore whether this bacterium also contributes to human or animal disease burden.

Recent developments in proteomic methods and disease biomarkers

Proteomic methodologies for identification and analysis of biomarkers have gained more attention during recent years and have evolved rapidly. Identification and detection of disease biomarkers are important to foresee outbreaks of certain diseases thereby avoiding surgery and other invasive and expensive medical treatments for patients. Thus, more research into discovering new biomarkers and new methods for faster and more accurate detection is needed. It is often difficult to detect and measure biomarkers because of their low concentrations and the complexity of their respective matrices. Therefore it is hard to find and validate methods for accurate screening methods suitable for clinical use. The most recent developments during the last three years and also some historical considerations of proteomic methodologies for identification and validation of disease biomarkers are presented in this review.

Sterile and microbial-associated intra-amniotic inflammation in preterm prelabor rupture of membranes

OBJECTIVE

The objectives of this study were to: (1) determine the amniotic fluid (AF) microbiology of patients with preterm prelabor rupture of membranes (PROM); and (2) examine the relationship between intra-amniotic inflammation with and without microorganisms (sterile inflammation) and adverse pregnancy outcomes in patients with preterm PROM.

METHODS

AF samples obtained from 59 women with preterm PROM were analyzed using cultivation techniques (for aerobic and anaerobic bacteria as well as genital mycoplasmas) and with broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS). AF concentration of interleukin-6 (IL-6) was determined using ELISA. Results of both tests were correlated with AF IL-6 concentrations and the occurrence of adverse obstetrical/perinatal outcomes.

RESULTS

(1) PCR/ESI-MS, AF culture, and the combination of these two tests each identified microorganisms in 36% (21/59), 24% (14/59) and 41% (24/59) of women with preterm PROM, respectively; (2) the most frequent microorganisms found in the amniotic cavity were Sneathia species and Ureaplasma urealyticum; (3) the frequency of microbial-associated and sterile intra-amniotic inflammation was overall similar [ 29% (17/59)]: however, the prevalence of each differed according to the gestational age when PROM occurred; (4) the earlier the gestational age at preterm PROM, the higher the frequency of both microbial-associated and sterile intra-amniotic inflammation; (5) the intensity of the intra-amniotic inflammatory response against microorganisms is stronger when preterm PROM occurs early in pregnancy; and (6) the frequency of acute placental inflammation (histologic chorioamnionitis and/or funisitis) was significantly higher in patients with microbial-associated intra-amniotic inflammation than in those without intra-amniotic inflammation [93.3% (14/15) versus 38% (6/16); p = 0.001].

CONCLUSIONS

(1) The frequency of microorganisms in preterm PROM is 40% using both cultivation techniques and PCR/ESI-MS; (2) PCR/ESI-MS identified microorganisms in the AF of 50% more women with preterm PROM than AF culture; and (3) sterile intra-amniotic inflammation was present in 29% of these patients, and it was as or more common than microbial-associated intra-amniotic inflammation among those presenting after, but not before, 24 weeks of gestation.

Sterile intra-amniotic inflammation in asymptomatic patients with a sonographic short cervix: prevalence and clinical significance

OBJECTIVE

To determine the frequency and clinical significance of sterile and microbial-associated intra-amniotic inflammation in asymptomatic patients with a sonographic short cervix.

METHODS

Amniotic fluid (AF) samples obtained by transabdominal amniocentesis from 231 asymptomatic women with a sonographic short cervix [cervical length (CL) ≤25 mm] were analyzed using cultivation techniques (for aerobic and anaerobic as well as genital mycoplasmas) and broad-range polymerase chain reaction (PCR) coupled with electrospray ionization mass spectrometry (PCR/ESI-MS). The frequency and magnitude of intra-amniotic inflammation [defined as an AF interleukin (IL)-6 concentration ≥2.6 ng/mL], acute histologic placental inflammation, spontaneous preterm delivery (sPTD), and the amniocentesis-to-delivery interval were examined according to the results of AF cultures, PCR/ESI-MS and AF IL-6 concentrations.

RESULTS

Ten percent (24/231) of patients with a sonographic short cervix had sterile intra-amniotic inflammation (an elevated AF IL-6 concentration without evidence of microorganisms using cultivation and molecular methods). Sterile intra-amniotic inflammation was significantly more frequent than microbial-associated intra-amniotic inflammation [10.4% (24/231) versus 2.2% (5/231); p < 0.001]. Patients with sterile intra-amniotic inflammation had a significantly higher rate of sPTD <34 weeks of gestation [70.8% (17/24) versus 31.6% (55/174); p < 0.001] and a significantly shorter amniocentesis-to-delivery interval than patients without intra-amniotic inflammation [median 35, (IQR: 10-70) versus median 71, (IQR: 47-98) days, (p < 0.0001)].

CONCLUSION

Sterile intra-amniotic inflammation is more common than microbial-associated intra-amniotic inflammation in asymptomatic women with a sonographic short cervix, and is associated with increased risk of sPTD (<34 weeks). Further investigation is required to determine the causes of sterile intra-amniotic inflammation and the mechanisms whereby this condition is associated with a short cervix and sPTD.

Prevalence of Borrelia miyamotoi in Ixodes ticks in Europe and the United States

Infection rates of Ixodes ticks with Borrelia miyamotoi in Europe and the United States vary greatly based upon location.

Borrelia miyamotoi, a relapsing fever-related spirochete transmitted by Ixodes ticks, has been recently shown to be a human pathogen. To characterize the prevalence of this organism in questing Ixodes ticks, we tested 2,754 ticks for a variety of tickborne pathogens by PCR and electrospray-ionization mass spectrometry. Ticks were collected from California, New York, Connecticut, Pennsylvania, and Indiana in the United States and from Germany and the Czech Republic in Europe from 2008 through 2012. In addition, an isolate from Japan was characterized. We found 3 distinct genotypes, 1 for North America, 1 for Europe, and 1 for Japan. We found B. miyamotoi infection in ticks in 16 of the 26 sites surveyed, with infection prevalence as high as 15.4%. These results show the widespread distribution of the pathogen, indicating an exposure risk to humans in areas where Ixodes ticks reside.

The Putative Role of Viruses, Bacteria, and Chronic Fungal Biotoxin Exposure in the Genesis of Intractable Fatigue Accompanied by Cognitive and Physical Disability

Patients who present with severe intractable apparently idiopathic fatigue accompanied by profound physical and or cognitive disability present a significant therapeutic challenge. The effect of psychological counseling is limited, with significant but very slight improvements in psychometric measures of fatigue and disability but no improvement on scientific measures of physical impairment compared to controls. Similarly, exercise regimes either produce significant, but practically unimportant, benefit or provoke symptom exacerbation. Many such patients are afforded the exclusionary, non-specific diagnosis of chronic fatigue syndrome if rudimentary testing fails to discover the cause of their symptoms. More sophisticated investigations often reveal the presence of a range of pathogens capable of establishing life-long infections with sophisticated immune evasion strategies, including Parvoviruses, HHV6, variants of Epstein-Barr, Cytomegalovirus, Mycoplasma, and Borrelia burgdorferi. Other patients have a history of chronic fungal or other biotoxin exposure. Herein, we explain the epigenetic factors that may render such individuals susceptible to the chronic pathology induced by such agents, how such agents induce pathology, and, indeed, how such pathology can persist and even amplify even when infections have cleared or when biotoxin exposure has ceased. The presence of active, reactivated, or even latent Herpes virus could be a potential source of intractable fatigue accompanied by profound physical and or cognitive disability in some patients, and the same may be true of persistent Parvovirus B12 and mycoplasma infection. A history of chronic mold exposure is a feasible explanation for such symptoms, as is the presence of B. burgdorferi. The complex tropism, life cycles, genetic variability, and low titer of many of these pathogens makes their detection in blood a challenge. Examination of lymphoid tissue or CSF in such circumstances may be warranted.

Borrelia burgdorferi not confirmed in human-biting Amblyomma americanum ticks from the southeastern United States

The predominant human-biting tick throughout the southeastern United States is Amblyomma americanum. Its ability to transmit pathogens causing Lyme disease-like illnesses is a subject of ongoing controversy. Results of previous testing by the Department of Defense Human Tick Test Kit Program and other laboratories indicated that it is highly unlikely that A. americanum transmits any pathogen that causes Lyme disease. In contrast, a recent publication by Clark and colleagues (K. L. Clark, B. Leydet, and S. Hartman, Int. J. Med. Sci. 10:915-931, 2013) reported detection of Lyme group Borrelia in A. americanum using a nested-flagellin-gene PCR. We evaluated this assay by using it and other assays to test 1,097 A. americanum ticks collected from humans. Using the Clark assay, in most samples we observed nonspecific amplification and nonrepeatability of results on subsequent testing of samples. Lack of reaction specificity and repeatability is consistent with mispriming, likely due to high primer concentrations and low annealing temperatures in this protocol. In six suspect-positive samples, Borrelia lonestari was identified by sequencing of an independent gene region; this is not a Lyme group spirochete and is not considered zoonotic. B. burgdorferi was weakly amplified from one pool using some assays, but not others, and attempts to sequence the amplicon of this pool failed, as did attempts to amplify and sequence B. burgdorferi from the five individual samples comprising this pool. Therefore, B. burgdorferi was not confirmed in any sample. Our results do not support the hypothesis that A. americanum ticks are a vector for Lyme group Borrelia infections.