Cerebrospinal fluid CXCL13 in non-borrelial central nervous system infections: contribution of CXCL13 to the differential diagnosis

BACKGROUND

The chemokine CXCL13 in cerebrospinal fluid (CSF) is used as a diagnostic marker of Lyme neuroborreliosis (LNB). However, the elevated levels in other non-borrelial CNS infections and the lack of a clearly defined cut-off value are limitations of the test.

METHODS

In our prospective study, we evaluated CSF CXCL13 levels in patients with LNB (47 patients), tick-borne encephalitis (TBE; 46 patients), enteroviral CNS infections (EV; 45 patients), herpetic CNS infections (HV; 23 patients), neurosyphilis (NS; 11 patients) and controls (46 patients). The correlation of CXCL13 with CSF mononuclears was determined in all groups.

RESULTS

Median CXCL13 was significantly higher in LNB group; however, the cut-off value of 162 pg/mL was also exceeded in 22% of TBE patients, 2% EV patients, 44% HV patients and in 55% patients with NS. Sensitivity and specificity were 0.83 and 0.78, respectively, with a Youden index of 0.62. CXCL13 was significantly correlated with CSF mononuclears (p = .0024), but the type of infectious agent had a greater influence on CXCL13 levels.

CONCLUSIONS

Increased CXCL13 levels are useful for LNB diagnostics, but other non-purulent CNS infections causes should be considered if intrathecal synthesis of borrelia specific antibodies is not confirmed or clinical manifestations are atypical.

Preparation of Certified Methodology for Testing Transdermal Absorption of Chemicals In Vitro

This publication presents the preparation of a certified methodology for in vitro transdermal absorption testing of chemicals and highlights the various pitfalls in their implementation. Vertical diffusion cells (Franz cells) were used to test the dermal absorption of caffeine, benzoic acid, and testosterone across a penetration membrane (porcine ear skin), while the receptor fluid samples were evaluated by HPLC. The designed methodology was certified in 2022 in the Good Laboratory Practice system and will be used at the VUOS Rybitví and at the Medical Faculty of the Charles University in Hradec Králové to assess the dermal absorption of various substances in the environment and occupational surroundings.

Long-term seed burial reveals differences in the seed-banking strategies of naturalized and invasive alien herbs

Soil seed viability and germinability dynamics can have a major influence on the establishment and spread of plants introduced beyond their native distribution range. Yet, we lack information on how temporal variability in these traits could affect the invasion process. To address this issue, we conducted an 8-year seed burial experiment examining seed viability and germinability dynamics for 21 invasive and 38 naturalized herbs in the Czech Republic. Seeds of most naturalized and invasive species persisted in the soil for several years. However, naturalized herbs exhibited greater seed longevity, on average, than invasive ones. Phylogenetic logistic models showed that seed viability (but not germinability) dynamics were significantly related to the invasion status of the study species. Seed viability declined earlier and more sharply in invasive species, and the probability of finding viable seeds of invasive species by the end of the experiment was low. Our findings suggest that invasive herbs might take advantage of high seed viability in the years immediately after dispersal, while naturalized species benefit from extended seed viability over time. These differences, however, are not sufficiently strong to explain the invasiveness of the species examined.

Seed viability of common ragweed (Ambrosia artemisiifolia L.) is affected by seed origin and age, but also by testing method and laboratory

Common ragweed (Ambrosia artemisiifolia L.) is an annual Asteraceae species native to North America which is highly invasive across Europe and has harmful impacts, especially on human health and agriculture. Besides its wide ecological range, particularly its high reproductive power by seeds is promoting its spread to various habitats and regions. To prevent further spread and to control the plant, the European Commission funded projects and COST-Actions involving scientists from all over Europe. A joint trial was set up comprising eight different laboratories from Europe to study seed viability variation in different seed samples. Three different testing methods (viability test with 2,3,5-triphenyltetrazolium chloride (TTC), a germination test combined with a subsequent TTC test and a crush test) were tested within the EU-COST-Action SMARTER network to four different seed origins. The viability test results from different laboratories were compared for variation amongst tests and laboratories. The main aim was to optimise the reliability of testing procedures, but results revealed not only significant effects of seed origin and seed age on seed viability, but also considerable differences between the output of the individual testing methods and furthermore between laboratories.

Due to these significant differences in the results of the testing labs, additionally a second test was set up. Twelve Austrian ragweed populations were used for TTC testing to obtain a precise adjustment of the testing method as well as a tight guideline for interpreting the results, particularly for the TTC state “intermediate” since a proper classification of TTC-intermediate coloured seeds is still a challenge when determining viability rates.

TRY plant trait database - enhanced coverage and open access

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.

Seed-bank dynamics of native and invasive Impatiens species during a five-year field experiment under various environmental conditions

Despite recent evidence on the important role of seed banks associated with plant invasions, and a large body of literature on invasive annual Impatiens species, little is known about the seed bank characteristics of Impatiens species. To bridge this gap, we conducted a five-year field experiment where we buried seeds of two invasive species (I. glandulifera and I. parviflora) and one native species (I. noli-tangere) across four localities in the Czech Republic, harbouring all three Impatiens species and differing in the environmental conditions. We found that the three Impatiens species differed in the characteristics of their seed banks. Both invasive species had a high seed germination rate of almost 100% in the first year after seed burial, while <50% of seeds of the native I. noli-tangere germinated during this year. In I. parviflora all seeds germinated in the first year after seed burial and later decomposed, i.e. the species had a transient seed bank. For I. glandulifera, the most invasive species, the survival of seeds differed among localities. At the first and second localities, the seeds decomposed in the first year after seed burial; in the third locality the seeds germinated in the second year; and in the fourth one, the seeds still germinated in the fourth year. The native I. noli-tangere formed a short-term persistent seed bank across all localities. Germinating or dormant seeds were found in the third year after burial in all localities, and in one locality the seeds persisted until the fifth year. The germination and dormancy in I. noli-tangere were constrained by low minimum temperatures during winter. In addition, germination was highest at intermediate soil moisture, and the most dormant seeds were recorded in soils with intermediate nitrogen concentration. The germination of I. glandulifera was slightly limited by low soil nitrogen. However, no such effect was found in I. parviflora. We suggest that in the invasive Impatiens species seed resistance to environmental factors and high germination at least partly explain their wide distribution.

Small genome separates native and invasive populations in an ecologically important cosmopolitan grass

The literature suggests that small genomes promote invasion in plants, but little is known about the interaction of genome size with other traits or about the role of genome size during different phases of the invasion process. By intercontinental comparison of native and invasive populations of the common reed Phragmites australis, we revealed a distinct relationship between genome size and invasiveness at the intraspecific level. Monoploid genome size was the only significant variable that clearly separated the North American native plants from those of European origin. The mean Cx value (the amount of DNA in one chromosome set) for source European native populations was 0.490 ± 0.007 (mean ± SD), for North American invasive 0.506 ± 0.020, and for North American native 0.543 ± 0.021. Relative to native populations, the European populations that successfully invaded North America had a smaller genome that was associated with plant traits favoring invasiveness (long rhizomes, early emerging abundant shoots, resistance to aphid attack, and low C:N ratio). The knowledge that invasive populations within species can be identified based on genome size can be applied to screen potentially invasive populations of Phragmites in other parts of the world where they could grow in mixed stands with native plants, as well as to other plant species with intraspecific variation in invasion potential. Moreover, as small genomes are better equipped to respond to extreme environmental conditions such as drought, the mechanism reported here may represent an emerging driver for future invasions and range expansions.

Unique double concentric ring organization of light harvesting complexes in Gemmatimonas phototrophica

The majority of life on Earth depends directly or indirectly on the sun as a source of energy. The initial step of photosynthesis is facilitated by light-harvesting complexes, which capture and transfer light energy into the reaction centers (RCs). Here, we analyzed the organization of photosynthetic (PS) complexes in the bacterium G. phototrophica, which so far is the only phototrophic representative of the bacterial phylum Gemmatimonadetes. The isolated complex has a molecular weight of about 800 ± 100 kDa, which is approximately 2 times larger than the core complex of Rhodospirillum rubrum. The complex contains 62.4 ± 4.7 bacteriochlorophyll (BChl) a molecules absorbing in 2 distinct infrared absorption bands with maxima at 816 and 868 nm. Using femtosecond transient absorption spectroscopy, we determined the energy transfer time between these spectral bands as 2 ps. Single particle analyses of the purified complexes showed that they were circular structures with an outer diameter of approximately 18 nm and a thickness of 7 nm. Based on the obtained, we propose that the light-harvesting complexes in G. phototrophica form 2 concentric rings surrounding the type 2 RC. The inner ring (corresponding to the B868 absorption band) is composed of 15 subunits and is analogous to the inner light-harvesting complex 1 (LH1) in purple bacteria. The outer ring is composed of 15 more distant BChl dimers with no or slow energy transfer between them, resulting in the B816 absorption band. This completely unique and elegant organization offers good structural stability, as well as high efficiency of light harvesting. Our results reveal that while the PS apparatus of Gemmatimonadetes was acquired via horizontal gene transfer from purple bacteria, it later evolved along its own pathway, devising a new arrangement of its light harvesting complexes.

The majority of life on Earth depends directly or indirectly on the sun as a source of energy. Phototrophic organisms use energy from light to power various cellular and metabolic processes. The initial step of photosynthesis is facilitated by light-harvesting complexes, which capture and transfer light energy into the reaction centers where it is used to power proton gradients or to form new chemical bonds. Here, we analyzed photosynthetic complexes in Gemmatimonas phototrophica, the only known phototrophic representative of the bacterial phylum Gemmatimonadetes. Using a combination of biochemical and spectroscopic techniques, we show that the light-harvesting complexes of G. phototrophica are organized in 2 concentric rings around the reaction center. This organization is unique among anoxygenic phototrophs. It offers both structural stability and high efficiency of light harvesting. The structural unit of both antenna rings is a dimer of photosynthetic pigments called bacteriochlorophyll. The inner ring is populated by more densely packed dimers, while the outer ring contains more distant dimers with a minimal excitation exchange. Such an arrangement modifies the spectral properties of bacteriochlorophylls in the complex and ensures efficient capture of light in the near-infrared part of the solar spectrum.

Detection of antigen-specific T cells in patients with neuroborreliosis

There is a lack of laboratory tests in clinical practice that can detect the activity of borrelial infection. This was the reason for testing an antigen-specific T-cell detection method in patients with neuroborreliosis: the ELISPOT method, which is capable of detecting antigen-specific T lymphocytes in clinical conditions. A group of 32 patients (20 diagnosed with neuroborreliosis; NB) was examined using this commercial method (LymeSpot intrerferon-γ Assay Kit®). Of these 20 NB patients, 10 were found to be positive and 10 negative; four of the five persons tested prior to the antibiotic treatment were positive. Eight patients served as the control group, giving four positive and four negative results. The results achieved so far appear to be unequivocal; still, the test could be expected: a) in non-specific clinical symptoms with borderline or negative proof of antibodies; b) in eraly stage of the disease; c) in the case of seropositivity and unequivocal clinical picture. The basic prerequisite for the clinical utilization of the method, however, is that it be thoroughly tested.

[Diagnostic relevance of the chemokine CXCL13 and anti-C6 peptide antibodies in patients with neuroborreliosis]

AIM OF THE STUDY

The study was focused on testing the diagnostic value of detection of the chemokine CXCL13 (B lymphocyte chemoattractant) and anti-C6 peptide (synthetic peptide derived from B. burdorferi VlsE protein) antibodies in patients with neuroborreliosis (NB).

MATERIAL AND METHODS

One hundred and twenty-nine patients with clinical suspicion of neuroinfection were included in the study. Eighty patients with NB (positive for antibodies in serum and CSF) were subdivided into four groups (A1-A4) based on positivity/negativity of the antibody index (AI) and pleocytosis. The control group was composed of 49 patients with a negative AI and absence of CSF pleocytosis. Chemokine CXCL13 and anti-C6 antibodies were examined by commercial kits (Human CXCL13/BLC/BCA-1 Immunoassay, R&D Systems, INC, USA and C6 B. burgdorferi (Lyme) ELISA, Immunetics Inc. USA). The CXCL13 cut-off values were set to 130 pg/ml for the CSF and 62 pg/ml for the serum.

RESULTS

The highest CSF levels of CXCL13 chemokine were found in group A1 (pleocytosis, AI positive), and they were significantly higher (p < 0.001) comparing with other groups except A3 (pleocytosis, AI negative; p = 0.04). Group A3 also showed significantly higher levels of CXCL13 than groups A2 (without pleocytosis, AI positive; p = 0.005), A4 (without pleocytosis, AI negative), and B (p < 0.001). The differences in the serum CXCL13 levels between groups were non-significant. The serum anti-C6 antibodies were detected in all NB groups and the positivity rates did not differ between groups (92%) except for A3 where 55% of the patients were positive. In the CSF, the highest anti-C6 sensitivity was found in the patients with a positive AI (A1 88.6%; A2 76.9%) while in the groups with a negative AI, it was low (A3 25%; A4 0%). In group B, anti-C6 antibodies were not detected.

CONCLUSION

The highest CSF CXCL13 levels were found in early stage NB. Elevated CXCL13 concentrations correlate better with pleocytosis than with AI positivity; however, there exist some patients with a positive AI who have low CXCL13 levels. These patients are most probably those in the late - subacute stage of neuroinfection. The CXCL13 testing seems to be the most diagnostically helpful in the acute stage of NB where AI is still negative. The clinical sensitivity of the C6 ELISA test appears to be insufficient for CSF examination under our conditions. On the contrary, the specificity of this test was proven high, because none of the controls tested positive.

Prospective study on the chemokine CXCL13 in neuroborreliosis and other aseptic neuroinfections

The study evaluates the clinical significance of CXCL13 (leukocyte chemoattractant synthesized in CSF ) in Lyme neuroborreliosis (LNB) and other aseptic CNS infections. 244 patients with symptoms of neuroinfection and/or LNB were divided into groups: A - patients with LNB-positive antibodies in serum and CSF (96) or CSF only (14); B - patients with aseptic non-borrelial neuroinfections (82); C - negative controls (52). Group A was divided into A1-A4 according to pleocytosis in CSF and AIIgG positivity. The highest CSF CXCL13 concentrations (max. 81,287.60pg/ml; median 1766.90pg/ml) were in A1 (positive AI, pleocytosis) and A3 (negative AIIgG, pleocytosis; max. 7201,60pg/ml, median 56.22pg/ml). A2 (positive AI without pleocytosis) and A4 (negative AI without pleocytosis) had low CXCL13 levels - A2 max. 650.50pg/ml (median<7.80pg/ml); A4 max. 118.56pg/ml (median<7.8pg/ml). In B the median was 28.10pg/ml (max. 595.87pg/ml). In C the CXCL13 concentrations were the lowest (max. 83.83pg/ml; median<7.80pg/ml). The lowest cut-off was 29pg/ml (sensitivity 90.0%, specificity 72.2%), the highest one 400pg/ml (sensitivity 59.6%, specificity 94.0%). The group differences of serum CXCL13 were insignificant. The highest concentrations were at the beginning of the disease. In LNB CXCL13 correlates better with the CSF pleocytosis than AI positivity.

Geographic structuring and transgenerational maternal effects shape germination in native, but not introduced, populations of a widespread plant invader

PREMISE OF THE STUDY

Germination is critical in determining species distributions and invasion dynamics. However, is it unclear how often invasive populations evolve germination characteristics different from native populations, because few studies have isolated genetic variation by using seed from garden-grown plants. Additionally, while herbivore-induced transgenerational effects are common, it is unknown whether maternal herbivory differentially shapes germination in native and introduced offspring.

METHODS

We explored germination in native and introduced populations of the North American invader Verbascum thapsus using seed from garden-grown maternal plants, half of which were protected from herbivores. To elucidate (1) germination niche breadth and (2) whether germination conditions affected expression of genetic structuring among populations, we germinated seed under four ecologically relevant temperature regimes.

KEY RESULTS

Native populations had a wide germination niche breadth, germinating as well as or better than introduced populations. At cooler temperatures, native populations exhibited a genetically based environmental cline indicative of local adaptation, with populations from warmer locales germinating better than populations from cooler locales. However, this cline was obscured when maternal plants were attacked by herbivores, revealing that local stressors can override the expression of geographic structuring. Introduced populations did not exhibit clinal variation, suggesting its disruption during the introduction process.

CONCLUSIONS

Native and introduced populations have evolved genetic differences in germination. The result of this difference manifests in a wider germination niche breadth in natives, suggesting that the invasive behavior of V. thapsus in North America is attributable to other factors.

Naturalization of central European plants in North America: species traits, habitats, propagule pressure, residence time

The factors that promote invasive behavior in introduced plant species occur across many scales of biological and ecological organization. Factors that act at relatively small scales, for example, the evolution of biological traits associated with invasiveness, scale up to shape species distributions among different climates and habitats, as well as other characteristics linked to invasion, such as attractiveness for cultivation (and by extension propagule pressure). To identify drivers of invasion it is therefore necessary to disentangle the contribution of multiple factors that are interdependent. To this end, we formulated a conceptual model describing the process of invasion of central European species into North America based on a sequence of "drivers." We then used confirmatory path analysis to test whether the conceptual model is supported by a statistical model inferred from a comprehensive database containing 466 species. The path analysis revealed that naturalization of central European plants in North America, in terms of the number of North American regions invaded, most strongly depends on residence time in the invaded range and the number of habitats occupied by species in their native range. In addition to the confirmatory path analysis, we identified the effects of various biological traits on several important drivers of the conceptualized invasion process. The data supported a model that included indirect effects of biological traits on invasion via their effect on the number of native range habitats occupied and cultivation in the native range. For example, persistent seed banks and longer flowering periods are positively correlated with number of native habitats, while a stress-tolerant life strategy is negatively correlated with native range cultivation. However, the importance of the biological traits is nearly an order of magnitude less than that of the larger scale drivers and highly dependent on the invasion stage (traits were associated only with native range drivers). This suggests that future research should explicitly link biological traits to the different stages of invasion, and that a failure to consider residence time or characteristics of the native range may seriously overestimate the role of biological traits, which, in turn, may result in spurious predictions of plant invasiveness.

Effect of temperature and nutrients on the growth and development of seedlings of an invasive plant

Plant species distributions are determined by the response of populations to regional climates; however, little is known about how alien plants that arrive in central Europe from climatically warmer regions cope with the temperature conditions at the early stage of population development. Ambrosia artemisiifolia (common ragweed) is an invasive annual plant causing considerable health and economic problems in Europe. Although climate-based models predict that the whole of the Czech Republic is climatically suitable for this species, it is confined to the warmest regions. To determine the factors possibly responsible for its restricted occurrence, we investigated the effects of temperature and nutrient availability on its seedlings. The plants were cultivated at one of seven temperature regimes ranging from 10 to 34 °C, combined with three nutrient levels. The data on the rate of leaf development were used to calculate the lower developmental threshold (LDT, the temperature, in °C, below which development ceases), the sum of effective temperatures (SET, the amount of heat needed to complete a developmental stage measured in degree days above LDT) and width of the thermal window. The rate of development decreased with decrease in temperature and nutrient supply. Besides this, the decrease in the availability of nutrients resulted in decreased LDT, increased SET and wider thermal window. The dependence of LDT and SET on the availability of nutrients contradicts the concept that thermal constants do not vary. Our results highlight temperature as the main determinant of common ragweed's distribution and identify nutrient availability as a factor that results in the realized niche being smaller than the fundamental niche; both of these need to be taken into account when predicting the future spread of A. artemisiifolia.

Getting the right traits: reproductive and dispersal characteristics predict the invasiveness of herbaceous plant species

To better understand the effect of species traits on plant invasion, we collected comparative data on 20 reproductive and dispersal traits of 93 herbaceous alien species in the Czech Republic, central Europe, introduced after 1500 A. D. We explain plant invasion success, expressed by two measures: invasiveness, i.e. whether the species is naturalized but non-invasive, or invasive; and dominance in plant communities expressed as the mean cover in vegetation plots. We also tested how important reproductive and dispersal traits are in models including other characteristics generally known to predict invasion outcome, such as plant height, life history and residence time. By using regression/classification trees we show that the biological traits affect invasion success at all life stages, from reproduction (seed production) to dispersal (propagule properties), and the ability to compete with resident species (height). By including species traits information not usually available in multispecies analyses, we provide evidence that traits do play important role in determining the outcome of invasion and can be used to distinguish between alien species that reach the final stage of the invasion process and dominate the local communities from those that do not. No effect of taxonomy ascertained in regression and classification trees indicates that the role of traits in invasiveness should be assessed primarily at the species level.

Effects of soil characteristics, allelopathy and frugivory on establishment of the invasive plant Carpobrotus edulis and a co-occurring native, Malcolmia littorea

BACKGROUND

The species Carpobrotus edulis, native to South Africa, is one of the major plant invaders of Mediterranean coastal ecosystems around the world. Invasion by C. edulis exerts a great impact on coastal habitats. The low number of native species in invaded communities points to the possible existence of mechanisms suppressing their germination. In this study we assessed whether soil factors, endozoochory, competition and allelopathic effects of the invader affect its own early establishment and that of the native species Malcolmia littorea. We used laboratory solutions representing different chemical composition and moisture of the soil, herbivore feeding assays to simulate seed scarification and rainwater solutions to account for the effect of differently aged C. edulis litter.

PRINCIPAL FINDINGS

We show that unlike that of the native species, germination and early growth of C. edulis was not constrained by low moisture. The establishment of C. edulis, in terms of germination and early growth, was increased by scarification of seeds following passage through the European rabbit intestines; the rabbits therefore may have potential implications for plant establishment. There was no competition between C. edulis and M. littorea. The litter of the invasive C. edulis, which remains on the soil surface for several years, releases allelopathic substances that suppress the native plant germination process and early root growth.

CONCLUSIONS

The invasive species exhibits features that likely make it a better colonizer of sand dunes than the co-occurring native species. Allelopathic effects, ability to establish in drier microsites and efficient scarification by rabbits are among the mechanisms allowing C. edulis to invade. The results help to explain the failure of removal projects that have been carried out in order to restore dunes invaded by C. edulis, and the long-lasting effects of C. edulis litter need to be taken into account in future restoration projects.

[Detection of borrelia DNA from patients with neuroborreliosis and erythema migrans]

AIM

Assessment of PCR procedure for proving of the Borrelia burgdorferi sensu lato DNA in nerve and skin forms of Lyme borreliosis.

METHODS

DNA from plasma, urine and CSF was isolated by QIAamp DNA mini kit. PCR was designed as two-step amplification (nested-PCR). Each sample was tested in PCR for five target sequences: two were specific for plasmide genes encoding OspA and OspC proteins and three correlated with genes for 16SrDNA, flagellin and p66 protein.

RESULTS

Borrelial DNA was proved in 41 patients suffering from neuroborreliosis out of 56 (77.4 %), among 48 patients with erythema migrans (EM) were found 26 positive (54.2 %). After treatment the specific DNA was detected in 22 patients with neuroborreliosis (41.5 %) and 16 patients with EM (38.1 %). Three months after the treatment 23 patients were positive in both of groups (28.7 %) and next 3 months later the specific DNA was found in 6 (9.5 %). The highest rate of positive results was manifested by 16SrDNA target, lower and comparable results were obtained by OspA, C and flagellin primers, the lowest rate was in p66 system.

CONCLUSION

The tested PCR proved specific DNA in all tested biological fluids in both of the clinical forms of Lyme borreliosis with a relatively high sensitivity. The proving of DNA can not be used for the assessment of the effect of treatment due to the long persistence of PCR positivity after antibiotic treatment. To achieve a sufficient diagnostic sensitivity of PCR it is desirable to use minimally two amplification systems in parallel.

Examination of specific DNA by PCR in patients with different forms of Lyme borreliosis

BACKGROUND

Borrelial specific DNA was examined in a group of 62 patients with different forms of Lyme borreliosis (LB) (32 patients suffered from neuroborreliosis, 19 manifested erythema migrans, and 11 joint involvement).

METHODS

Nested-PCR system with five newly derived primers was used in parallel. The study was organized prospectively, the presence of DNA was tested for plasma, CSF, joint fluid and urine before treatment, and plasma, joint fluid and urine were examined after treatment.

RESULTS

Before therapy, 36 patients (58.1%) were DNA positive on the whole; 21 positive patients (65.6%) were found in the group of neuroborreliosis, 8 (42.1%) showed signs of skin involvement, and 7 (63.6%) were positive in arthritis. After treatment, 11 patients (36.7%) were positive in neuroborreliosis, 3 (17.6%) in skin form, and 6 (54.5%) in joint form of LB. Among 97 positive amplifications the most frequent target was found in primer corresponding with 16S rDNA (50 samples, 51.5%). Lower but very similar results were obtained with primers for OspA (18 positive amplifications; 18.6%), OspC (13 positive amplifications; 13.4%), and flagellin (13 positive amplifications; 13.4%). There were 11 patients in whom only DNA and no specific antibodies were found.

CONCLUSIONS

Specific DNA was found in all clinical groups of LB with similar sensitivity. Examination of the borrelial DNA in urine displayed the same sensitivity as in CSF and had a two times higher sensitivity than in plasma.

[First experience with detecting bacterial DNA in the cerebrospinal fluid of patients with purulent meningitis using broad spectrum multiplex nested PCR]

OBJECTIVES

To propose and verify a PCR assay for detecting Escherichia coli, Haemophilus influenzae, Listeria monocytogenes, Staphylococcus species, Streptococcus pneumoniae and Neisseria meningitidis serogroups B and C in a single sample of the cerebrospinal fluid of patients with purulent meningitis.

MATERIAL AND METHODS

DNA from the cerebrospinal fluid was isolated using the QIAamp DNA Mini Kit. PCR was performed as two-step amplification (nested PCR). For E. coli, H. influenzae, L. monocytogenes, S. species and S. pneumoniae, universal and species-specific primers encoding bacterial 16S rDNA were used in the first and second reaction, respectively. For N. meningitidis serogroups B and C, an amplification system with primers for the SiaD gene was utilized.

RESULTS

Of 25 patients examined at the beginning of their treatment, bacterial DNA was detected in the cerebrospinal fluid of 17 (68 %) of them. Those were six cases of N. meningitidis serogroup B, four of N. meningitidis serogroup C, five of S. pneumoniae, one of H. influenzae and one of L. monocytogenes. Of 7 patients in whom antibiotic therapy was initiated prior to diagnostic lumbar puncture, PCR was positive in four cases.

CONCLUSIONS

The proposed nested PCR approach is faster than traditional culture methods and suitable for early laboratory diagnosis of infectious agents. When compared to culture methods, the technique offers slightly higher positivity (by 16 %). This is similar in samples analyzed after the initiation of antibiotic therapy. The PCR method never detected other bacteria than the cultured ones.

[The demonstration of tuberculosis using molecular genetic methods polymerase chain reaction (PCR) and Amplified Mycobacterium tuberculosis direct (AMTD) test]

INTRODUCTION

Tuberculosis is a communicable disease, in most instances with a chronic course. The aetiological agent is Mycobacterium tuberculosis. Its demonstration is based on microscopic investigations and cultures. Microscopy is not sufficiently sensitive, while cultures are lengthy. One of the possibilities of speeding up diagnosis are molecular genetic methods.

PURPOSE OF THE STUDY

To compare the demonstration of mycobacteria using molecular genetic methods with the results of cultures.

METHODS

We used two methods to demonstrate the nucleic acid complex of Mycobacterium tuberculosis-the polymerase chain reaction (PCR) and the Amplified Mycobacterium tuberculosis direct test (AMTD). We investigated 647 samples. Out of these, 275 samples were tested with PCR and 372 were investigated with a AMTD set. At the same time we started for each sample a parallel culture.

RESULTS

In 275 samples, out of a total of 647, which were analysed with PCR, mycobacterial DNA was demonstrated in 18 (6.5 %). Out of the 372 samples investigated with AMTD, mycobacterial RNA was demonstrated in 27 (7 %). Out of the 18 PRC positive samples, 6 (13 %) did not yield a positive mycobacterial culture. Out of the 27 positive results RNA with the AMTD method 17 did not yield positive cultures. On the other hand, a diagnosis of tuberculosis verified by cultures without a positive PCR was found in 2 patients (0.7 %). Disagreement between the results of AMTD and cultures was also found in 2 samples (0.5 %).

CONCLUSIONS

Molecular genetic methods substantially speed up the diagnosis of tuberculosis. These methods are particularly important in cases of paucibacillary material and of unique and unrepeatable samples (tissues biopsies, nodes, cerebrospinal fluid). Given the possibility of false positive results, parallel verification by microscopy and cultures is essential.

[West Nile virus fever]

West Nile virus (WNV) is a member of the Flaviviridae family, genus Flavivirus. Its reservoir hosts are wild birds. Infection is transmitted to humans by infected mosquitoes of the genus Culex. In most cases, it is either asymptomatic or manifests itself as mild fever. Typically, WNV illnesshas a sudden onset with fever above 39 degrees C and accompanying symptoms such as chills, headache, arthralgia, myalgia, back ache, cough and sore throat. Gastrointestinal symptoms are frequently reported. Generalized lymphadenopathy and conjunctivitis may develop. In some patients the infection can progress to meningoencephalitis. Diagnosis is currently based on detection of IgM antibodies in blood and cerebrospinal fluid or direct detection of WNV RNA.

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.

[Detection of anti-Ehrlichia antibodies and direct demonstration of Ehrlichia nucleic acid using the polymerase chain reaction (PCR) in patients in the Czech Republic]

PURPOSE OF THE STUDY

In patients presenting symptoms with a suspicion of ehrlichiosis we determined antiehrlichia antibodies and investigated the presence of Ehrlichia nucleic acid in the plasma.

MATERIAL AND METHODS

In our group were 46 patients with tick sucks in their case history, who presented symptoms compatible with ehrlichiosis. Anti-Ehrlichia antibodies were determined by an indirect immunofluorescent test with a commercial kit from MRL Diagnostics. Ehrlichia DNA was detected using a nested PCR - the target sequence was a part of the antigen Anaplasma phagocytophilum.

RESULTS

Antibodies against HGE agents were demonstrated in 28 % of the patients; 10.5 % of the patients had in their serum antibodies reacting to the Ehrlichia chaffeensis antigen. The nucleic acid of A. phagocytophilum was detected in 11 % of the patients.

CONCLUSIONS

The Czech population is relatively often exposed to Ehrlichia infections. Although most cases are asymptomatic, we should bear in mind this diagnosis, especially in immunodeficient patients, where early treatment may prevent a complicated course of the disease.