An optimized PCR leads to rapid and highly sensitive detection of Borrelia burgdorferi in patients with Lyme borreliosis

Molecular detection of Borrelia theileri in cattle in Korea

Bovine borreliosis, caused by Borrelia theileri which is transmitted via hard tick bites, is associated with mild clinical symptoms, such as fever, lethargy, hemoglobinuria, anorexia, and anemia. Borrelia theileri infects various animals, such as cattle, deer, horses, goats, sheep, and wild ruminants, in Africa, Australia, and South America. Notably, no case of B. theileri infection has been reported in Korean cattle to date. In this study, 101 blood samples were collected from a Korean indigenous cattle breed, among which 1.98% tested positive for B. theileri via nested PCR. The obtained sequences exhibited high homology with B. theileri strains identified in other regions. Phylogenetic analysis of 16S rRNA confirmed the B. theileri group affiliation; however, flagellin B sequences exhibited divergence, potentially due to regional evolutionary differences. This study provides the first molecular confirmation of B. theileri infection in Korean livestock. Further isolation and nucleotide sequence analyses are necessary to better understand the presence of B. theileri strains in cows in Korea.

Direct Capture and Early Detection of Lyme Disease Spirochete in Skin with a Microneedle Patch

Borrelia burgdorferi sensu lato family of spirochetes causes Lyme disease (LD) in animals and humans. As geographic territory of ticks expands across the globe, surveillance measures are needed to measure transmission rates and provide early risk testing of suspected bites. The current standard testing of LD uses an indirect two-step serological assay that detects host immune reactivity. Early detection remains a challenge because the host antibody response develops several weeks after infection. A microneedle (MN) device was developed to sample interstitial fluid (ISF) and capture spirochetes directly from skin. After sampling, the MN patch is easily dissolved in water or TE buffer, and the presence of spirochete DNA is detected by PCR. Performance was tested by spiking porcine ear skin with inactivated Borrelia burgdorferi, which had an approximate recovery of 80% of spirochetes. With further development, this simple direct PCR method could be a transformative approach for early detection of the causative agent of Lyme disease and enable rapid treatment to patients when infection is early, and numbers of systemic spirochetes are low.

Quantified Detection of Treponema pallidum DNA by PCR Assays in Urine and Plasma of Syphilis Patients

Treponema pallidum can invade any organ, and T. pallidum DNA can be detected in various tissues and fluids. However, the knowledge of the presence and loads of T. pallidum DNA in urine is limited. For this study, we enrolled 208 syphilis patients (34 primary syphilis, 61 secondary syphilis, 68 latent syphilis, and 45 symptomatic neurosyphilis) and collected urine and plasma samples from them. polA and Tpp47 genes were amplified in urine supernatant, urine sediment, and plasma using nested PCR and droplet digital PCR assays. The detection rates were 14.9% (31 of 208) and 24.2% (50 of 207) in urine supernatant and sediment, respectively (P = 0.017). The detection rates of T. pallidum DNA in urine sediment were 47.1, 47.5, 4.4, and 4.5% for primary, secondary, latent, and symptomatic neurosyphilis, respectively. After treatment, T. pallidum DNA in urine in 20 syphilis patients turned negative. Loads of T. pallidum DNA in urine sediment were significantly higher than those in plasma and urine supernatant (both P < 0.05). Our study indicated that T. pallidum DNA in urine could be found in patients at all stages of syphilis and showed high loads in urine sediment. Though it is unlikely to improve the routine diagnostic algorithm, the detection of T. pallidum DNA in urine may play certain roles in cases difficult to diagnose. In addition, urine is abundant and convenient to collect; therefore, urine sediment could be an ideal specimen for acquiring an amount of T. pallidum DNA that can be supplement samples for the detection of molecular typing of T. pallidum.

IMPORTANCE Syphilis is a sexually transmitted disease caused by Treponema pallidum sub. pallidum.T. pallidum can invade many organs, and T. pallidum DNA can be detected in various tissues and fluids. The results reported here demonstrated that T. pallidum DNA could be detected in urine in patients at all stages of syphilis. The detection rate and loads of T. pallidum DNA in urine sediment were significantly higher than those in urine supernatant. Urine is abundant, and its collection is noninvasive and convenient; therefore, urine is an ideal sample for acquiring a large amount of T. pallidum DNA, which can be supplement samples for the detection of molecular typing of T. pallidum.

Establishment of Amblyomma americanum populations and new records of Borrelia burgdorferi-infected Ixodes scapularis in South Dakota

Tick-borne diseases are an emerging public health threat in the United States, but surveillance is lacking in some regions. To advance current knowledge of the ecology of ticks and tick-borne diseases in South Dakota, we conducted a survey in the summer of 2019, focusing on the eastern counties of the state. We collected and identified 266 ticks and a subset were tested for the presence of Borrelia burgdorferi by polymerase chain reaction (PCR). Dermacentor variabilis, a ubiquitous species in the state, was the most commonly identified tick, present in all counties surveyed. However, we also identified 15 Amblyomma americanum from three different locations, providing the first evidence of established populations in the state and expanding the range of this species. In addition, we identified 22 Ixodes scapularis from five different locations, confirming a previous report of an established population in the state. Two adult I. scapularis from two different sites were found to harbor B. burgdorferi, including an individual from Lincoln County, suggesting the ongoing presence of the pathogen in tick populations in the state and representing its southwestern-most detection in the midwest United States. These findings provide important information for assessing and monitoring the public health risk from tick-borne diseases in an area where surveillance is lacking.

Lyme Disease Biosensors: A Potential Solution to a Diagnostic Dilemma

Over the past four decades, Lyme disease has remained a virulent and pervasive illness, persisting throughout North America and many other regions of the world. Recent increases in illness in many countries has sparked a renewed interest in improved Lyme diagnostics. While current standards of diagnosis are acceptable for the late stages of the disease, it remains difficult to accurately diagnose early forms of the illness. In addition, current diagnostic methods tend to be relatively expensive and require a large degree of laboratory-based analysis. Biosensors represent the fusion of biological materials with chemical techniques to provide simple, inexpensive alternatives to traditional diagnostic methods. Lyme disease biosensors have the potential to better diagnose early stages of the illness and provide possible patients with an inexpensive, commercially available test. This review examines the current state of Lyme disease biosensing, with a focus on previous biosensor development and essential future considerations.

Pilot Study of Immunoblots with Recombinant Borrelia burgdorferi Antigens for Laboratory Diagnosis of Lyme Disease

Accurate laboratory diagnosis of Lyme disease (Lyme borreliosis), caused by the spirochete Borrelia burgdorferi (BB), is difficult and yet important to prevent serious disease. The US Centers for Disease Control and Prevention (CDC) presently recommends a screening test for serum antibodies followed by confirmation with a more specific Western blot (WB) test to detect IgG and IgM antibodies against antigens in whole cell lysates of BB. Borrelia species related to BB cause tick-borne relapsing fever (TBRF). TBRF is increasingly recognized as a health problem in the US and occurs in areas where Lyme disease is prevalent. The two groups of Borrelia share related antigens. We have developed a modified WB procedure termed the Lyme immunoblots (IBs) using recombinant antigens from common strains and species of the BB sensu lato complex for serological diagnosis of Lyme disease. A reference collection of 178 sera from 26 patients with and 152 patients without Lyme disease were assessed by WB and IB in a blinded manner using either criteria for positive antibody reactions recommended by the CDC or criteria developed in-house. The sensitivity, specificity, positive and negative predictive values obtained with the reference sera suggest that the Lyme IB is superior to the Lyme WB for detection of specific antibodies in Lyme disease. The Lyme IB showed no significant reaction with rabbit antisera produced against two Borrelia species causing TBRF in the US, suggesting that the Lyme IB may be also useful for excluding TBRF.

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.

Development of a sensitive PCR-dot blot assay to supplement serological tests for diagnosing Lyme disease

Laboratory diagnosis of Lyme disease is difficult and presently dependent on detecting Borrelia burgdorferi-specific antibodies in patient serum with the disadvantage that the immune response to B. burgdorferi can be weak or variable, or alternatively, the slow and inefficient culture confirmation of B. burgdorferi. PCR tests have previously shown poor sensitivity and are not routinely used for diagnosis. We developed a sensitive and specific Lyme Multiplex PCR-dot blot assay (LM-PCR assay) applicable to blood and urine samples to supplement western blot (WB) serological tests for detecting B. burgdorferi infection. The LM-PCR assay utilizes specific DNA hybridization to purify B. burgdorferi DNA followed by PCR amplification of flagellin and OspA gene fragments and their detection by southern dot blots. Results of the assay on 107 and 402 clinical samples from patients with suspected Lyme disease from Houston, Texas or received at the IGeneX laboratory in Palo Alto, California, respectively, were analyzed together with WB findings. The LM-PCR assay was highly specific for B. burgdorferi. In the Texas samples, 23 (21.5%) patients antibody-negative in WB assays by current US Centers for Disease Control (CDC) recommended criteria were positive by LM-PCR performed on urine, serum or whole blood samples. With IGeneX samples, of the 402 LM-PCR positive blood samples, only 70 met the CDC criteria for positive WBs, while 236 met IGeneX criteria for positive WB. Use of the LM-PCR assay and optimization of current CDC serological criteria can improve the diagnosis of Lyme disease.

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.

A high-throughput genetic screen identifies previously uncharacterized Borrelia burgdorferi genes important for resistance against reactive oxygen and nitrogen species

Borrelia burgdorferi, the causative agent of Lyme disease in humans, is exposed to reactive oxygen and nitrogen species (ROS and RNS) in both the tick vector and vertebrate reservoir hosts. B. burgdorferi contains a limited repertoire of canonical oxidative stress response genes, suggesting that novel gene functions may be important for protection of B. burgdorferi against ROS or RNS exposure. Here, we use transposon insertion sequencing (Tn-seq) to conduct an unbiased search for genes involved in resistance to nitric oxide, hydrogen peroxide, and tertiary-butyl hydroperoxide in vitro. The screens identified 66 genes whose disruption resulted in increased susceptibility to at least one of the stressors. These genes include previously characterized mediators of ROS and RNS resistance (including components of the nucleotide excision repair pathway and a subunit of a riboflavin transporter), as well as novel putative resistance candidates. DNA repair mutants were among the most sensitive to RNS in the Tn-seq screen, and survival assays with individual Tn mutants confirmed that the putative ribonuclease BB0839 is involved in resistance to nitric oxide. In contrast, mutants lacking predicted inner membrane proteins or transporters were among the most sensitive to ROS, and the contribution of three such membrane proteins (BB0017, BB0164, and BB0202) to ROS sensitivity was confirmed using individual Tn mutants and complemented strains. Further analysis showed that levels of intracellular manganese are significantly reduced in the Tn::bb0164 mutant, identifying a novel role for BB0164 in B. burgdorferi manganese homeostasis. Infection of C57BL/6 and gp91phox-/- mice with a mini-library of 39 Tn mutants showed that many of the genes identified in the in vitro screens are required for infectivity in mice. Collectively, our data provide insight into how B. burgdorferi responds to ROS and RNS and suggests that this response is relevant to the in vivo success of the organism.

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.

Technical and clinical validation of three commercial real-time PCR kits for the diagnosis of neuroborreliosis in cerebrospinal fluid on three different real-time PCR platforms

This study reports the evaluation of the technical and clinical validation of the O-DiaBorburg kit (DIA), Borrelia burgdorferi PCR kit, ISEX (GENE), and Borrelia burgdorferi sensu lato Real-TM (SAC) for the diagnosis of neuroborreliosis in cerebrospinal fluid based on both Borrelia DNA and CSF samples from patients with clinical suspicion of neuroborreliosis. This validation study was done by analysing the kits on the Rotorgene Q (RGQ), CFX96, and LightCycler480 (LC480). For all kits, the linear range was larger on RGQ than on CFX96 and LC480. A good reproducibility was obtained for all assays on all instruments. Storage at -20 °C resulted in a decreased reproducibility for SAC. Results of the limit of detection (LOD₉₅) experiments indicated a better sensitivity than described in the kit insert for all kits on all PCR platforms. No cross-reactivity was found for genetically related organisms nor for other pathogens which may be present in CSF. All species of the Borrelia burgdorferi sensu lato complex were detected with the GENE and SAC kits. The DIA kit failed to detect B. lusitaniae. The results seemed to indicate a better overall performance for the GENE kit on RGQ. However, its diagnostic value could not be confirmed in the clinical validation study, wherein none of the 103 CSF samples from clinical neuroborreliosis cases showed a positive real-time PCR result with the GENE kit analysed on RGQ.

Optimized testing for C. trachomatis DNA in synovial fluid samples in clinical practice

AIM

No standardized polymerase chain reaction (PCR) assay is available for detection of Chlamydia trachomatis (C. tr.) in synovial fluid (SF) for diagnostic use in clinical practice. This study tested the performance of two optimized molecular biology methods, to determine which is best suited for detecting C. tr. in SF clinical samples from patients with various rheumatologic diseases.

METHODS

Two DNA extraction methods, i.e., (1) alkaline lysis and (2) QIAEX II Gel Extraction Kit® + cetyltrimethylammonium bromide (CTAB; Qiagen, Hilden, Germany), and C. tr.-omp1-152 bp PCR were tested in SF samples from a total of 329 patients with the following diagnoses: reactive arthritis (ReA; n = 10, 4 patients had posturethritic ReA), undifferentiated arthritis (UA; n = 66), rheumatoid arthritis (RA; n = 169), psoriatic arthritis (PSA; n = 12), and osteoarthritis (OA) n = 72.

RESULTS

In SF samples, C. tr.-omp1-152 bp PCR in combination with alkaline lysis DNA extraction allowed detection of more C. tr.-positive samples: 3/10 (30%) ReA patients (all with posturethritic ReA) and 20/66 (38%) UA patients were positive, compared to the 0/10 (0%) patients with ReA and 1/66 (2%) with UA detected using the QIAEX II Gel Extraction Kit® + CTAB. Moreover, 2/12 (17%) SF samples from PSA patients tested positive with alkaline lysis. All samples from patients with OA and RA tested negative.

CONCLUSION

Alkaline lysis in combination with C. tr.-omp1-152 bp PCR emerged as the most sensitive method for identification of C. tr. in clinical SF samples.

Global Tn-seq analysis of carbohydrate utilization and vertebrate infectivity of Borrelia burgdorferi

Borrelia burgdorferi maintains a complex life cycle between tick and vertebrate hosts. Although some genes have been identified as contributing to bacterial adaptation in the different hosts, the list is incomplete. In this manuscript, we report the first use of transposon mutagenesis combined with high-throughput sequencing (Tn-seq) in B. burgdorferi. We utilize the technique to investigate mechanisms of carbohydrate utilization in B. burgdorferi and the role of carbohydrate metabolism during mouse infection. We performed genetic fitness analyses to identify genes encoding factors contributing to growth on glucose, maltose, mannose, trehalose and N-acetyl-glucosamine. We obtained insight into the potential functions of proteins predicted to be involved in carbohydrate utilization and identified additional factors previously unrecognized as contributing to the metabolism of the tested carbohydrates. Strong phenotypes were observed for the putative carbohydrate phosphotransferase transporters BB0408 and BBB29 as well as the response regulator Rrp1. We further validated Tn-seq for use in mouse studies and were able to correctly identify known infectivity factors as well as additional transporters and genes on lp54 that may contribute to optimal mouse infection. As such, this study establishes Tn-seq as a powerful method for both in vitro and in vivo studies of B. burgdorferi.

Improving urine sample efficacy as a convenient alternative for invasive samples in molecular diagnosis of toxoplasmosis

BACKGROUND

Diagnosis of some diseases is difficult due to invasive sampling. Urine has been candidate as a non-invasive and convenient alternative. It has many advantages and easy accessibility but some technical ills should be removed. Finding a suitable extraction method for improving urine DNA quantity and quality in altering invasive specimens for molecular diagnosis of some infectious diseases, was the main object of present research.

METHOD

Toxoplasmosis was selected as an experimental model, regarding the congenital and ocular forms, its abundance and requirement to invasive sample for diagnosis. Samples prepared by adding some defined Toxoplasma gondii (RH strain) tachyzoites to normal urine. Several urine DNA extraction and purification methods comparatively were tested for finding the best one. The amount of extracted DNA assessed using Nanodrope spectrophotometer and a multiplex semi-nested PCR were designed for evaluating the results.

RESULTS

Urine samples with known number of tachyzoites were purified comparatively by five better methods. The results reviled that Cinnagen kit performed with more efficacies. It works well up to 1-5tachyzoites µl(-1) of urine. The amount and quality of extracted DNA of more than 100 urine samples with defined tachyzoites were analyzed using a nested PCR method. Finally methods were enough sensitive to detect one tachyzoite DNA in final PCR reaction.

CONCLUSION

This method was enough eligible and sensitive to perform molecular tests for different purposes of instance detecting toxoplasmosis by urine sample as a convenience and non invasive method; although it is better to perform some more experiments using patients samples comparing gold methods.

Northern white-breasted hedgehogs Erinaceus roumanicus as hosts for ticks infected with Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum in Romania

Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum are two tick-borne pathogens of medical and/or veterinary importance which are distributed worldwide. Erinaceus roumanicus, the Northern white-breasted hedgehog, is a common synanthropic species that is known to carry not only the hedgehog tick, Ixodes hexagonus, but also I. ricinus, the most common European tick species. I. ricinus is the main vector of both mentioned pathogens. Within this framework and because only limited information is available on the role of E. roumanicus in the ecology of B. burgdorferi s.l. and Anaplasma phagocytophilum in Europe, we carried out an epidemiological surveillance on this species in Romania. From the 57 examined hedgehogs collected in 12 different counties, 24 presented tick infestation. Most ticks (n=959) were morphologically identified as larvae, nymphs, or adults of I. ricinus. The prevalence of B. burgdorferi s.l. was 0.4%, and that of A. phagocytophilum 12%. In all positive cases for B. burgdorferi s.l., restriction fragment length polymorphism revealed the genospecies B. afzelii. In Romania, only limited information is available on the epidemiology of B. burgdorferi s.l. and A. phagocytophilum. As hedgehogs commonly share the same environment with humans and other potential reservoir hosts for tick-borne pathogens, our study provides new epidemiological data of public health importance.

Abundance of Ixodes ricinus and prevalence of Borrelia burgdorferi s.l. in the nature reserve Siebengebirge, Germany, in comparison to three former studies from 1978 onwards

BACKGROUND

During the last decades, population densities of Ixodes ricinus and prevalences of Borrelia burgdorferi s.l. have increased in different regions in Europe. In the present study, we determined tick abundance and the prevalence of different Borrelia genospecies in ticks from three sites in the Siebengebirge, Germany, which were already examined in the years 1987, 1989, 2001 and 2003. Data from all investigations were compared.

METHODS

In 2007 and 2008, host-seeking I. ricinus were collected by monthly blanket dragging at three distinct vegetation sites in the Siebengebirge, a nature reserve and a well visited local recreation area near Bonn, Germany. In both years, 702 ticks were tested for B. burgdorferi s.l. DNA by nested PCR, and 249 tick samples positive for Borrelia were further genotyped by reverse line blotting.

RESULTS

A total of 1046 and 1591 I. ricinus were collected in 2007 and 2008, respectively. In comparison to previous studies at these sites, the densities at all sites increased from 1987/89 and/or from 2003 until 2008. Tick densities and Borrelia prevalences in 2007 and 2008, respectively, were not correlated for all sites and both years. Overall, Borrelia prevalence of all ticks decreased significantly from 2007 (19.5%) to 2008 (16.5%), thus reaching the same level as in 2001 two times higher than in 1987/89 (7.6%). Since 2001, single infections with a Borrelia genospecies predominated in all collections, but the number of multiple infections increased, and in 2007, for the first time, triple Borrelia infections occurred. Prevalences of Borrelia genospecies differed considerably between the three sites, but B. garinii or B. afzelii were always the most dominant genospecies. B. lusitaniae was detected for the first time in the Siebengebirge, also in co-infections with B. garinii or B. valaisiana.

CONCLUSIONS

Over the last two centuries tick densities have changed in the Siebengebirge at sites that remained unchanged by human activity since they belong to a nature reserve. Abiotic and biotic conditions most likely favored the host-seeking activity of I. ricinus and the increase of multiple Borrelia infections in ticks. These changes have led to a potential higher risk of humans and animals to be infected with Lyme borreliosis.

Nucleic Acid Amplification Based Diagnostic of Lyme (Neuro-)borreliosis - Lost in the Jungle of Methods, Targets, and Assays?

Laboratory based diagnosis of infectious diseases usually relies on culture of the disease causing micro-organism, followed by identification and susceptibility testing. Since Borrelia burgdorferi sensu lato, the etiologic agent of Lyme disease or Lyme borreliosis, requires very specific culture conditions (e.g. specific liquid media, long term cul-ture) traditional bacteriology is often not done on a routine basis. Instead, confirmation of the clinical diagnosis needs ei-ther indirect techniques (like serology or measurement of cellular activity in the presence of antigens) or direct but culture independent techniques, like microscopy or nucleic acid amplification techniques (NAT), with polymerase chain reaction (PCR) being the most frequently applied NAT method in routine laboratories.

NAT uses nucleic acids of the disease causing micro-organism as template for amplification, isolated from various sources of clinical specimens. Although the underlying principle, adoption of the enzymatic process running during DNA duplication prior to prokaryotic cell division, is comparatively easy, a couple of ‘pitfalls’ is associated with the technique itself as well as with interpretation of the results.

At present, no commercial, CE-marked and sufficiently validated PCR assay is available. A number of homebrew assays have been published, which are different in terms of target (i.e. the gene targeted by the amplification primers), method (nested PCR, PCR followed by hybridization, real-time PCR) and validation criteria. Inhibitory compounds may lead to false negative results, if no appropriate internal control is included. Carry-over of amplicons, insufficient handling and workflow and/or insufficiently validated targets/primers may result in false positive results. Different targets may yield different analytical sensitivity, depending, among other factors, of the redundancy of a target gene in the genome. Per-formance characteristics (e.g. analytical sensitivity and specificity, clinical sensitivity and specificity, reproducibility, etc.) are, if available, only applicable to a specific assay, running in a specific laboratory. Finally, not only the NAT/PCR method itself, but also the process of DNA isolation from the specimen, is highly diverse and may have fundamental im-pact on the (expected) PCR result. Of concern are distribution effects of DNA, in particular, if only low numbers of bacte-ria/genomes are present in a sample, as it is the case for instance in cerebrospinal fluids.

For the ordering physician and for the patient requesting PCR analysis, these ‘pitfalls’ are usually invisible. As a conse-quence, the reported result (i.e. PCR negative or positive for B. burgdorferi) is hard to interpret, especially, if the reported PCR result is contradictory to the clinical diagnosis or other laboratory findings. Moreover, due to the high number of dif-ferent assays in use, two laboratories, testing the same specimen, might come to different PCR results.

The current paper wants to summarize the available PCR/NAT assays for the detection of B. burgdorferi DNA in clinical specimens, with special attention to neurologic disorders, and to discuss the difficulties in PCR analysis and result inter-pretation, associated thereof. In view of growing numbers of patients who are diagnosed of having Lyme disease, and ac-knowledging a substantial growth in knowledge regarding other tick- or vector-borne pathogens, which might be able to induce symptoms comparable to Lyme (neuro-)borreliosis, efforts are urgently needed to standardize and harmonize methods for B. burgdorferi nucleic acid amplification.

First report of Borrelia burgdorferi sensu lato in two threatened carnivores: the marbled polecat, Vormela peregusna and the European mink, Mustela lutreola (Mammalia: Mustelidae)

Background

Lyme disease is a widespread cosmopolitan zoonosis caused by species belonging to the genus Borrelia. It is transmitted from animal reservoir hosts to humans through hard - ticks of genus Ixodes which are vectors of the disease.

Case presentation

Borrelia burgdorferi sensu lato infection was identified in a marbled polecat, Vormela peregusna, and two European minks, Mustela lutreola, from Romania, by PCR. RFLP revealed the presence of a single genospecies, Borrelia burgdorferi sensu stricto.

Conclusions

This is the first report of the Lyme disease spirochetes in the two mentioned hosts.

The amber theory of Lyme arthritis: initial description and clinical implications

Lyme arthritis differs in many respects from other bacterial causes of arthritis. Based on an observation made for a patient with Lyme arthritis, we propose that the pathogenesis of joint swelling in Lyme arthritis is due to the introduction into the joint space of non-viable spirochetes or more likely spirochetal debris enmeshed in a host-derived fibrinous or collagenous matrix. This "amber" hypothesis can account for the clinical and laboratory features of Lyme arthritis and is amenable to experimental validation. Validation would directly impact the clinical management of patients with Lyme arthritis.

Burden and viability of Borrelia burgdorferi in skin and joints of patients with erythema migrans or lyme arthritis

OBJECTIVE

To determine the burden and viability of Borrelia burgdorferi in the skin and joints of patients with Lyme disease.

METHODS

Standard and quantitative polymerase chain reaction (PCR) techniques were used to detect B burgdorferi DNA in skin samples from 90 patients with erythema migrans (EM) and in synovial fluid (SF) from 63 patients with Lyme arthritis (LA) and in synovial tissue from 9 patients. Quantitative PCR determinations of B burgdorferi DNA, messenger RNA (mRNA), and ribosomal RNA (rRNA) were made in 10 skin samples from EM patients and 11 SF samples from LA patients.

RESULTS

Skin lesions in most patients with EM had positive PCR results for B burgdorferi DNA. In the majority of patients with LA, a late disease manifestation, PCR results in pretreatment SF samples were positive. In patients with antibiotic-refractory arthritis, positive PCR results persisted for as long as 11 months, but positive results in samples taken during the postantibiotic period did not correlate with relapse or with the subsequent duration of arthritis, and at synovectomy, all results of PCR of synovial tissue were negative. B burgdorferi mRNA, a marker of spirochetal viability, was detected in 8 of 10 skin samples from EM patients, but in none of 11 SF samples from LA patients, even when obtained prior to antibiotic administration. Moreover, the median ratio of spirochetal rRNA to DNA, a measure of ribosomal activity, was 160 in the 10 EM skin samples, but only 0.15 in the 3 LA SF samples with positive results.

CONCLUSION

B burgdorferi in the skin lesions of EM patients were active and viable, whereas those in the SF of LA patients were moribund or dead at any time point. Thus, detection of B burgdorferi DNA in SF is not a reliable test of active joint infection in Lyme disease.

Molecular diagnosis of Borrelia bacteria for the diagnosis of Lyme disease

INTRODUCTION

Lyme borreliosis is the most common vector-borne disease in the temperate climate zone of Europe and the US, and its frequency is increasing. Serology is often negative in the early stage of Lyme borreliosis and cannot distinguish between active and past infection. Culture is cumbersome and not very sensitive, and polymerase chain reaction (PCR) for the diagnosis of Lyme borreliosis has been described over the last 20 years, with varying results.

AREAS COVERED

In this article, all of the major studies in which PCR has been used to diagnose Lyme borreliosis in humans are critically reviewed. However, this article does not include studies that consisted of fewer than 10 patients, nor does it include studies that have inadequate descriptions of the patient population.

EXPERT OPINION

There is a lack of standardized protocols, and preamplification procedures have not been standardized. Nested PCRs seem to perform best, but are prone to contamination. PCR on skin biopsies can be used to diagnose early Lyme borreliosis in patients with atypical forms of erythema migrans. PCR also has diagnostic potential in Lyme arthritis and early neuroborreliosis. Blood and urine should not used for PCR. For future development, preamplification procedures should be optimized using materials from experimentally infected animals. Multi-center studies should follow to evaluate these optimized tests.

Ticks and Lyme borreliosis in an alpine area in northeast Italy

A 2-year study was conducted in a mountainous area of northeast Italy to evaluate the occurrence and distribution of ticks, as well as to assess the prevalence of the spirochaete Borrelia burgdorferi sensu lato. All ticks collected were Ixodes ricinus L. (Parasitiformes: Ixodidae). In general, most nymphs and adult ticks were collected from April to July. Tick density was highly variable among sites; however, two areas with different infestation levels were recognized. Prevalences of B. burgdorferi s.l. in nymphal stages were rather variable between sites; overall the prevalence of infected nymphs in the whole area was slightly higher than 20%. The prevalence of B. burgdorferi s.l. in nymphs does not seem to be correlated with nymph density. The correlation between the incidence of Lyme borreliosis (reported human cases/1000 inhabitants/year) and Borrelia prevalence in nymphs was not significant, although a significant correlation was found between borreliosis incidence and nymph density.

Detection of Chlamydia trachomatis-DNA in synovial fluid: evaluation of the sensitivity of different DNA extraction methods and amplification systems

INTRODUCTION

Polymerase chain reaction (PCR) and ligase chain reaction (LCR) are used in research for detection of Chlamydia trachomatis (C. tr.) in synovial fluid (SF). However there is no standardized system for diagnostic use in clinical practice, therefore this study aimed at determining the molecular biology method best suited to detect C. tr. from SF.

METHODS

SF samples were spiked with C. tr. elementary bodies (EB) and human peripheral blood monocytes (PBMo) persistently infected with C. tr. in vitro to evaluate the sensitivity of different molecular biology methods and assays. Five different DNA-extraction methods were tested: 1) Alkaline lysis, 2) QIAex II Gel Extraction Kit+ CTAB, 3) Chelex-extraction, 4) QIAmp Tissue Kit and 5) QIAmp DNA Stool Kit. All DNA extracts were subjected to 5 different DNA amplification systems to detect C. tr.- DNA in the spiked SF samples: two C. tr. -omp1-- directed PCR, one C. tr.-plasmid-PCR, one C. tr. -16s RNA directed PCR, and one commercially available LCR (LCX), Abbott laboratories).

RESULTS

In SF samples spiked with C. tr.-EB and with C. tr.-PBMo, alkaline lysis, detecting 1 C. tr.-EB/ml SF, 0,1 C. tr.-PBMo/ml SF and QIAmp gel extraction kit+ CTAB detecting 0,1 C. tr. -EB/ml SF, 1 C. tr.-PBMo/ml, respectively, allowed most sensitive detection of the organism in combination with the C. tr.- omp1-(152 bp) PCR. Sensitivity decreased in all methods after storage of the DNA of C. tr.- dilution series at -20 degrees C for 4 months by at least one log phase.

CONCLUSIONS

The sensitivity to detect C. tr.- DNA from SF is highly dependent on the DNA extraction method and the detection system applied. Alkaline lysis as well as the QIAmp Gel extraction kit + CTAB in combination with C. tr.- omp1 - (152 bp) PCR evolved as the most sensitive methods to identify C. tr. in serial dilutions.

[Lyme arthritis in children and adolescents]

Lyme arthritis is one of the manifestations of Lyme disease and is caused by infection with Borrelia burgdorferi sensu lato. This article reviews the current knowledge regarding the epidemiology, etiology and pathogenesis as well as the clinical manifestations, the diagnosis, treatment and prognosis with special emphasis on children and adolescents.

Place des méthodes biologiques dans le diagnostic des manifestations de la borréliose de Lyme

Lyme borreliosis (LB) is a multisystemic infection transmitted by ticks. Its diagnosis is based on clinical and biological criteria. These criteria could be different in Europe than in the USA, because of the existence of multiples strains of borrelia in Europe. In primary stage of LB, the diagnosis is often clinical. In the secondary stage, LB diagnosis is established with an Elisa serology confirmed by a Western blot. The interpretation criteria of these laboratory tests should follow European recommendations (EUCALB). LB with neurological involvement should be confirmed by screening for intrathecal synthesis of borrelia antibodies in CSF. LB with rheumatologic expression could be confirmed by screening for borrelia in joint fluid by PCR. There is no strong marker of activity of the disease. Follow-up for LB is difficult, because antibodies may persist for years and LB does not confer immunization.

Detection of DNA from a range of bacterial species in the knee joints of dogs with inflammatory knee arthritis and associated degenerative anterior cruciate ligament rupture

Mixtures of bacterial nucleic acids can often be detected in synovial joints affected with arthritis. We investigated the potential role of such mixtures of bacterial nucleic acids in the pathogenesis of arthritis in a naturally occurring canine model. Dogs with a common inflammatory knee arthritis in which associated pathological degenerative anterior cruciate ligament (ACL) rupture often develops were studied. Synovial biopsies were obtained from 43 dogs with the naturally occurring ACL rupture arthropathy, 12 dogs with normal knees and intact ACL, and 16 dogs with normal knees and experimentally induced ACL rupture. Using PCR, specimens were tested for Borrelia burgdorferi OspA and p66 gene sequences. Broad-ranging 16S rRNA primers were also used; 'panbacterial' PCR products were cloned and multiple clones were sequenced for bacterial identification. Synovium was also studied histologically. The presence of bacterial DNA within the synovium was significantly associated with the naturally occurring ACL rupture arthropathy (p<0.05); knee joints from 37% of these dogs were PCR-positive. Mixtures of bacterial DNA were common and often included environmental bacteria; predominant organisms included Borrelia burgdorferi and Stenotrophomonas maltophilia. DNA from environmental bacteria was only found in dogs with the naturally occurring ACL rupture arthopathy; joints from 33% of affected dogs contained such bacterial DNA. Synovial inflammation developed in dogs with both naturally occurring and experimentally induced ACL rupture, when compared with intact ACL controls (p<0.01). These results indicate that mixtures of DNA derived from environmental bacteria are commonly found in the knee joint of a naturally occurring canine arthropathy, often in association with a recognized joint pathogen. Our results also suggest that knee instability alone is not responsible for this finding and have led us to hypothesize that mixtures of bacterial DNA are an important causative factor in the pathogenesis of inflammatory arthritis in this canine model.

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

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

PCR in lyme neuroborreliosis: a prospective study

OBJECTIVES

DNA proof is the only widely available direct diagnostic tool in Lyme borreliosis. Sensitive PCR detecting of spirochetal DNA was prepared and a prospective study in neuroborreliosis was performed.

MATERIALS AND METHODS

57 hospitalised patients with active neuroborreliosis and proved CSF antibodies synthesis were examined. Nested-PCR (utilizing three targets) was used for the detection of specific DNA in plasma, CSF and urine.

RESULTS

Before treatment 36 positive patients (63.1%) were found in all tested specimens in parallel, 28 patients (49.1%) were positive in urine, 20 in CSF (35.0%) and 16 in plasma 28.0%). Later only urine was tested and the following results were obtained: 17 positive patients (30.0%) immediately after treatment, 8 (14.0%) after 3 months and one patient persisted positivity after 6 months.

CONCLUSIONS

The highest sensitivity of PCR was achieved in the acute period of neuroborreliosis - 63.1% in three body fluids comparing with CSF antibody synthesis.

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

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

Diagnostic utility of Borrelia burgdorferi cerebrospinal fluid polymerase chain reaction in children with Lyme meningitis

BACKGROUND

Cerebrospinal fluid (CSF) laboratory tests are frequently collected to help differentiate Lyme meningitis from other causes of aseptic meningitis. Previous studies using Lyme CSF polymerase chain reaction (PCR) have yielded varied results (sensitivity between 10 and 90%). No studies have specifically examined the diagnostic utility of Lyme CSF-PCR in North American children with Lyme meningitis.

METHODS

Retrospective chart review of children presenting to a children's hospital in a Lyme-endemic region between October 1999 and September 2004. Patients were included if they had both Lyme serology and Lyme CSF-PCR performed during the same hospital encounter and had documented meningitis. Patients were considered to have Lyme meningitis if they had meningitis and met CDC criteria for Lyme disease. The Lyme CSF-PCR assay amplified a Borrelia burgdorferi DNA flagellin gene sequence.

RESULTS

Of 108 patients with meningitis who qualified for the study, 20 patients met criteria for Lyme meningitis and 88 were classified as aseptic meningitis. Positive Lyme CSF-PCR was found in 1 patient (1 of 20, 5%) with Lyme meningitis and one patient classified as aseptic meningitis (1 of 88, 1%). Lyme CSF-PCR had a sensitivity of 5% and a specificity of 99%. The only Lyme meningitis patient with positive Lyme CSF-PCR had the highest CSF white blood cell count and CSF protein values compared with the other Lyme meningitis patients.

CONCLUSIONS

This is the first study to evaluate Lyme CSF-PCR exclusively in North American children. This commercially available laboratory test is not generally helpful for identifying Lyme meningitis because of its low sensitivity.

Diagnosis of lyme borreliosis

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

Molecular identification and analysis of Borrelia burgdorferi sensu lato in lizards in the southeastern United States

Lyme borreliosis (LB) group spirochetes, collectively known as Borrelia burgdorferi sensu lato, are distributed worldwide. Wild rodents are acknowledged as the most important reservoir hosts. Ixodes scapularis is the primary vector of B. burgdorferi sensu lato in the eastern United States, and in the southeastern United States, the larvae and nymphs mostly parasitize certain species of lizards. The primary aim of the present study was to determine whether wild lizards in the southeastern United States are naturally infected with Lyme borreliae. Blood samples obtained from lizards in Florida and South Carolina were tested for the presence of LB spirochetes primarily by using B. burgdorferi sensu lato-specific PCR assays that amplify portions of the flagellin (flaB), outer surface protein A (ospA), and 66-kDa protein (p66) genes. Attempts to isolate spirochetes from a small number of PCR-positive lizards failed. However, PCR amplification and sequence analysis of partial flaB, ospA, and p66 gene fragments confirmed numerous strains of B. burgdorferi sensu lato, including Borrelia andersonii, Borrelia bissettii, and B. burgdorferi sensu stricto, in blood from lizards from both states. B. burgdorferi sensu lato DNA was identified in 86 of 160 (54%) lizards representing nine species and six genera. The high infection prevalence and broad distribution of infection among different lizard species at different sites and at different times of the year suggest that LB spirochetes are established in lizards in the southeastern United States.

Improving the specificity of 16S rDNA-based polymerase chain reaction for detecting Borrelia burgdorferi sensu lato-causative agents of human Lyme disease

AIMS

16S rDNA sequences of Borrelia burgdorferi sensu lato were aligned with the 16S rDNA sequences of Borrelia hermsii, Borrelia turicatae, and Borrelia lonestari in order to identify primers that might be used to more specifically identify agents of human Lyme disease in ticks in human skin samples.

METHODS AND RESULTS

Standard polymerase chain reaction (PCR), using an oligonucleotide sequence, designated TEC1, was shown, in combination with a previously developed primer (LD2) to amplify strains of B. burgdorferi sensu stricto, Borrelia afzelii, and Borrelia garinii, but not the non-Lyme causing B. hermsii or B. turicatae. This primer pair, designated Bbsl, was successfully used to amplify B. burgdorferi sensu lato from skin biopsies of patients with Lyme disease symptoms as well as from Ixodes scapularis, Amblyomma americanum and Dermacentor variabilis ticks.

CONCLUSIONS

The primer set Bbsl allows for the rapid detection and differentiation of B. burgdorferi sensu lato from non-Lyme disease-causing Borrelia species in ticks and human tissues.

SIGNIFICANCE AND IMPACT OF THE STUDY

The PCR primer set, Bbsl, will greatly facilitate detection of the causative agents of Lyme disease in infected ticks and human skin samples assisting in epidemiological studies, and potentially allowing for a more rapid diagnosis of the disease in patients.

Production of prostaglandin E2 in monocytes stimulated in vitro by Chlamydia trachomatis, Chlamydophila pneumoniae, and Mycoplasma fermentans

Chlamydia trachomatis (CT) as well as Chlamydophila pneumoniae (CP) cause chronic inflammatory diseases in humans. Persistently infected monocytes are involved in the pathogenesis by inducing mediators of inflammation. An in vitro system of chlamydial persistence in human peripheral blood monocytes (HPBM) was used to investigate prostaglandin E(2) (PGE(2)) production and the expression of the key enzyme for prostaglandin production, cyclooxygenase-2 (COX-2). PGE(2) production was determined by PGE(2)-ELISA of HPBM-culture supernatants. Cox-2 mRNA expression was measured by real-time RT-PCR of total RNA isolated from HPBM. Both, CT and CP, stimulated PGE(2) production of HPBM in vitro. Equivalent numbers of CT per host cell induced a higher PGE(2)-response compared to CP. The amount of synthesized PGE(2) depended on the chlamydial multiplicity of infection (MOI). Even at an MOI of 10 the amount of CT- and CP-induced prostaglandin, respectively, was lower than the amount of prostaglandin induced by E. coli lipopolysaccharide (LPS) at a concentration of 10microg/ml. In contrast to stimulation with LPS, Chlamydia-induced PGE(2) production as well as cox-2 mRNA decreased after day 1 post infection (p.i.). These data indicate that Chlamydia stimulate PGE(2) production in human monocytes. Since Chlamydia are often contaminated by mycoplasma, the influence of mycoplasma on the prostaglandin production was investigated additionally. Mycoplasma fermentans (MF) also stimulated PGE(2) production. The co-infection of mycoplasma and Chlamydia resulted in an additive effect in the production of PGE(2). Thus it is important to use host cells and Chlamydia free of mycoplasma contamination for the analysis of Chlamydia-induced prostaglandin production.

Vectors of tick-borne diseases and epidemiological situation in Latvia in 1993-2002

During the period of 1993-2002 an increase and the remarkable changes in the incidence of tick-borne encephalitis (TBE) and Lyme borreliosis (LB) as well as annual activities of vector species were noticed. The highest increase of TBE morbidity in Latvia has been observed in 1994 and 1995, and less expressed also in 1998 which was followed by a significant decrease during subsequent years. Whereas the highest peak of LB morbidity has been noticed in 1998 with only a minor decrease during subsequent years. Two epidemiologically significant Ixodes tick species are common in Latvia. Ixodes ricinus L. spread in the western and central part of Latvia; but rarely and in small numbers also in the eastern part. Ixodes persulcatus P. Sch. seems to dominate only in the eastern part of the country. The changes of seasonal and annual activities of I. ricinus were observed in two types of monitoring sites--sylvatic and peridomestic, located in the central part of Latvia. Observations of I. persulcatus were made in the eastern districts. Comparing geographically the Tick-borne diseases (TBD) incidence data for three tick distribution regions (I. ricinus dominated, I. persulcatus dominated and mixed regions), it was observed that the trend of annual changes in LB incidence during the last decade is almost of the same kind for all regions. Whereas TBE incidence extremes in 1994 and 1995 were observed almost only in I. ricinus dominated region. The annual field-collected adult tick infection rate with TBE virus (TBEV) from 1993 to 2002 for I. ricinus adults varied between 1.7% and 26.6% and for I. persulcatus--between 0% and 37.3%. The infection level in ticks removed from humans was much higher and from 1998 to 2002 surpassed 30%. TBEV investigations of removed adults and nymphs in 2002 discovered a high TBEV prevalence also in I. ricinus nymphs (43%). Typing of TBE virus isolated from ticks and patient serum samples in collaboration with German and Swedish virologists revealed that all three TBEV subtypes were co-circulating in Latvia. The mean annual tick infection rate with Borrelia burgdorferi s.l. analysed by means of a nested polymerase chain reaction of OspA gene fragment during the period of 1999-2001 was 18%-38% for I. ricinus adults and 25%-51% for I. persulcatus adults. Typing of Borrelia-positive DNA samples indicated that B. afzelii was dominant in Borrelia-positive I. ricinus (64.9%) and I. persulcatus (81.2%) followed by B. garinii (I. ricinus: 24.3%; in I. persulcatus: 14.5%). Investigations of Ehrlichia phagocytophila genogroup (by nested PCR targeted the 16S rRNA gene) revealed the presence of Ehrlichia sp. in I. ricinus from the central part of Latvia. Obtained data on TBD vectors and the epidemiological situation during the last decade indicates the complex impact of different factors influencing TBE and LB morbidity in Latvia.

Identification of three clinically relevant Borrelia burgdorferi sensu lato genospecies by PCR-restriction fragment length polymorphism analysis of 16S-23S ribosomal DNA spacer amplicons

We report the results of a study of the prevalences of three clinically relevant Borrelia burgdorferi sensu lato genospecies (Borrelia burgdorferi sensu stricto, Borrelia afzelii, and Borrelia garinii) in 1,040 questing Ixodes ticks from all regions of Latvia, where Lyme borreliosis is endemic. The prevalences of Borrelia in Ixodes ricinus and Ixodes persulcatus were 22.6 and 27.9%, respectively. Molecular typing of B. burgdorferi from infected ticks was performed by restriction fragment length polymorphism (RFLP) analysis of PCR-amplified fragments of the 16S-23S (rrs-rrlA) rRNA intergenic spacer by using species-specific primers and subsequent sequencing. The dominant Borrelia species in both Ixodes species was B. afzelii. In addition, different restriction patterns of B. garinii and B. afzelii were also identified. This study demonstrates that the 16S-23S rRNA PCR-RFLP typing method is simple, sensitive, and fast and that it allows one to differentiate among B. burgdorferi species and subspecies with various degrees of pathogenic potential directly in ticks. These features are important in monitoring Lyme disease.

Direct detection methods for Lyme Borrelia, including the use of quantitative assays

Direct detection of Borrelia burgdorferi sensu lato, the etiologic agent of Lyme borreliosis, is the most reliable laboratory diagnostic tool. Several methods have been developed for direct detection of B. burgdorferi in infected vectors, host tissues, and clinical specimens from patients with Lyme borreliosis. These include microscope-based assays, antigen detection assays, in vitro cultivation, and nucleic acid-based detection of B. burgdorferi. The sensitivity and specificity of these methods depend on various factors and are also variable among laboratories. To date, only in vitro cultivation of B. burgdorferi has been widely accepted to confirm clinical diagnosis of Lyme borreliosis. Nevertheless, various polymerase chain reaction-based molecular assays have shown increasing significance in the laboratory diagnosis of Lyme borreliosis because of their high sensitivity, specificity, and capability for quantification and typing of spirochetes in clinical specimens. In this review, the currently available methods for direct detection of B. burgdorferi in clinical samples and quantitative analysis of spirochete load in different biological sources are discussed.

An ospA-polymerase chain reaction/restriction fragment length polymorphism-based method for sensitive detection and reliable differentiation of all European Borrelia burgdorferi sensu lato species and OspA types

We describe a sensitive and reliable method for detection and differentiation of the five relevant European Borrelia burgdorferi sensu lato species ( B. burgdorferi sensu stricto, B. afzelii, B. garinii, B. valaisiana, and B. lusitaniae), based on a heminested ospA-PCR followed by restriction enzyme analysis. Sensitivity was one borrelia per PCR except for B. afzelii, where it was five per PCR. None of seven relapsing fever borreliae, eight Leptospira serovars or two Treponema species were amplified. Except B. garinii, each of the five B. burgdorferi s.l. species is represented by one or two characteristic restriction fragment length polymorphism (RFLP) patterns. Analysis of the heterogeneous group of B. garinii resulted in five different RFLP patterns, corresponding to the OspA types 3-7 associated with this species. In a pilot study on 529 Ixodes ricinus ticks from three different regions in Southern Germany, all species and OspA types were found except B. lusitaniae and B. garinii OspA type 7, arguing for a broad distribution of almost all OspA types. A further notable finding was the focal prevalence of OspA type 4, which has rarely been detected in ticks previously. Thus, the developed method provides a fast and simple tool for epidemiological studies on the heterogeneity of species and OspA types in Europe which has important implications for the development of vaccines and (microbiological) test systems for Europe.

Detection and molecular typing of Borrelia burgdorferi sensu lato in Ixodes ricinus ticks and in different patient samples from southwest Germany

The prevalence of different genospecies of Borrelia burgdorferi sensu lato in infected ticks could be a determinant for the risk of acquiring Lyme borreliosis (LB) and its clinical presentation. A total of 7373 ticks and 2761 samples from LB patients from the same area in southwest Germany were analyzed by PCR to assess the frequency of the occurrence of LB-associated genospecies. Fifteen percent of the tick samples and 19% of the human samples were found positive for the presence of B. burgdorferi sensu lato. Further identification of 1106 B. burgdorferi sensu lato positive tick samples by reverse line blotting and 125 positive patient samples by nested PCR using species-specific primers revealed the occurrence of B. afzelii, B. burgdorferi sensu stricto, B. garinii and B. valaisiana. Both single-species and mixed infections were noted and a similar distribution of the different genospecies was found in ticks compared with human samples. It was also the purpose of this study to obtain more information about a possible correlation between the distribution of Borrelia species and clinical syndromes of LB. Skin biopsies of 59 patients with acrodermatitis chronica atrophicans and cerebrospinal fluid samples from 78 patients with possible neuroborreliosis were analyzed. In conclusion, the distribution of the different genospecies in ticks is the decisive factor for the occurrence of the different Borrelia genospecies in samples from LB patients. Borrelia afzelii is the predominant genospecies in all kind of samples from the observed area and there seems to be no association of particular Borrelia genospecies with distinct clinical manifestations of LB.

Importance of sample preparation for molecular diagnosis of lyme borreliosis from urine

Urine PCR has been used for the diagnosis of Borrelia burgdorferi infection in recent years but has been abandoned because of its low sensitivity and the irreproducibility of the results. Our study aimed to analyze technical details related to sample preparation and detection methods. Crucial for a successful urine PCR were (i) avoidance of the first morning urine sample; (ii) centrifugation at 36,000 x g; and (iii) the extraction method, with only DNAzol of the seven different extraction methods used yielding positive results with patient urine specimens. Furthermore, storage of frozen urine samples at -80 degrees C reduced the sensitivity of a positive urine PCR result obtained with samples from 72 untreated erythema migrans (EM) patients from 85% in the first 3 months to <30% after more than 3 months. Bands were detected at 276 bp on ethidium bromide-stained agarose gels after amplification by a nested PCR. The specificity of bands for 32 of 33 samples was proven by hybridization with a GEN-ETI-K-DEIA kit and for a 10 further positive amplicons by sequencing. By using all of these steps to optimize the urine PCR technique, B. burgdorferi infection could be diagnosed by using urine samples from EM patients with a sensitivity (85%) substantially better than that of serological methods (50%). This improved method could be of future importance as an additional laboratory technique for the diagnosis of unclear, unrecognized borrelia infections and diseases possibly related to Lyme borreliosis.

Laboratory testing for suspected Lyme disease

Laboratory testing for B. burgdorferi infection is intended to substantiate a physician's clinical judgment of whether a patient has Lyme disease or not. Cultivation of B. burgdorferi from a patient's skin or blood is the gold standard for demonstration of active infection, but it is expensive and lacks clinical sensitivity. Detection of spirochetal DNA in clinical samples by PCR has better sensitivity, but PCR for B. burgdorferi has not yet been standardized for more routine diagnostic testing. Detection of antibodies to B. burgdorferi is the most practical and common approach for laboratory work-up of a case of suspected Lyme disease. Serologic assays fall short of 100% sensitivity and specificity, however, and examination of a single specimen in time does not discriminate between previous and ongoing infection. Because of a background false positivity even among healthy populations of nonendemic regions, serologic testing is recommended only when there is at least a one in five chance, in the physician's estimation, that the patient has active Lyme disease. The pretest likelihood of the disease is determined by the physician in the context of epidemiologic and clinical facts of the case. This estimate can serve to reassure patients who are at low risk of B. burgdorferi infection but are seeking a Lyme test for complaints of a more nonspecific nature. Although new subunit serologic assays based on recombinant proteins are becoming available commercially, the longstanding two-test approach, in which a positive or indeterminate result with a standardized, sensitive ELISA test is followed by verification with a more specific Western blot assay, still provides the physician with a reasonably accurate and reliable assessment of the presence of antibodies to B. burgdorferi. More recent challenges for serologic testing are seropositivity in the population as the result of immunization with the Lyme disease vaccine and the emergence of new Borrelia species that cause Lyme disease-like illnesses.

Sensitive detection of Borrelia burgdorferi sensu lato DNA and differentiation of Borrelia species by LightCycler PCR

In order to differentiate species within the Borrelia burgdorferi sensu lato complex, LightCyler PCR and melting-curve analysis of the amplicons of two genes with intraspecies variability, the p66 gene and the recA gene, were performed. It was demonstrated that nested LightCycler PCR amplification of p66 is more sensitive in the detection of borrelia DNA than amplification of the recA gene. B. burgdorferi sensu stricto could be differentiated from Borrelia garinii and Borrelia afzelii by melting-curve analysis of the p66 gene amplicon. B. garinii could be differentiated from B. afzelii and B. burgdorferi sensu stricto by melting-curve analysis of the recA gene amplicon. Therefore, the PCRs complement each other in subtyping different Borrelia species, and combined LightCycler PCR and melting-curve analysis of both target genes is a rapid method to distinguish the three species of B. burgdorferi sensu lato.