Third-generation cephalosporin resistant gram-negative bacteraemia in patients with haematological malignancy; an 11-year multi-centre retrospective study

Objectives

Among patients with haematological malignancy, bacteraemia is a common complication during chemotherapy-induced neutropenia. Resistance of gram-negative bacteria (GNB) to third-generation cephalosporins (3GC) is increasing. In order to explore the value of using surveillance cultures to guide empirical treatment e.g. choosing between carbapenem versus ceftazidime- we aimed to assess the distribution of pathogens causing bacteraemia in patients with haematological malignancy, and the proportion of 3GC-resistant GNB (3GC-R GNB) bacteraemia that was preceded by 3GC-R GNB colonization.

Methods

Using 11 years of data (2008–2018) from the Dutch national antimicrobial resistance surveillance system, we assessed the prevalence of 3GC-R GNB in episodes of bacteraemia, and the proportion of 3GC-R GNB bacteraemia that was preceded by 3GC-R GNB colonization. Colonization was defined as availability of any GNB surveillance isolate in the year before, independent of the causative micro-organism (time-paired isolates).

Results

We included 3887 patients, representing 4142 episodes of bacteraemia. GNB were identified in 715/4142 (17.3%), of which 221 (30.9%) were 3GC-R GNB. In 139 of these 221 patients a time-paired surveillance culture was available. In 76.2% (106/139) of patients these surveillance cultures already showed 3GC-R GNB isolates in the year prior to the culture date of the 3GC-R GNB positive blood isolate.

Conclusions

This multi-centre study shows that in patients with haematological malignancy, the majority of 3GC-R GNB bacteraemia is preceded by 3GC-R GNB colonization. Prospective clinical studies are needed to assess the safety and benefits of the use of surveillance-cultures to guide empirical therapy to restrict the empirical use of carbapenems in this population.

Treatment, recurrence rates and follow-up of Tenosynovial Giant Cell Tumor (TGCT) of the foot and ankle-A systematic review and meta-analysis

Background

The tenosynovial giant cell tumor (TGCT) is a usually benign lesion which arises from the synovium. It affects joints, tendon sheaths and bursae. The clinical course is often unpredictable, and local recurrences frequently occur. The aim of this study was to describe different treatment options, surgical complications, and to develop a follow-up regime based on a systematic literature review and meta-analysis of foot and ankle lesions.

Methods and results

1284 studies published between 01/1966 and 06/2021 were identified. 25 met the inclusion criteria, with a total of 382 patients. Of these, 212 patients had a diffuse (dTGCT) and 170 a localized (lTGCT) TGCT. Patients with a dTGCT had a mean age of 36.6±8.2 years, and 55% were female. The overall complication rate was 24% in dTGCT, irrespective of the therapeutic procedure; the mean follow-up was 37.9±27.4 months with a recurrence rate of 21%, and recurrences occurred between 3 and 144 months, the vast majority (86%) within the first 5 years following intervention. Patients with a lTGCT had a mean age of 31.2±5.7 years, and 53% were female. Complications occurred in 12%. The mean follow-up was 51.1±24.6 months, the recurrence rate was 7%, and recurrence occurred between 1 and 244 months after intervention.

Conclusion

Diffuse TGCTs of the foot and ankle region have a remarkable recurrence rate irrespective of therapeutic procedures, and most lesions reoccurred within 5, with more than half of these in the first 2 years. The lTGCTs are well treatable lesions, with a low recurrence and a moderate complication rate. Based on these findings, we propose a follow-up regime for the dTGCT including a clinical survey and MR imaging 3 months after surgical intervention (baseline), followed by twice-yearly intervals for the first 2 years, yearly intervals up to the fifth year, and further individual follow-up due to the fact that recurrences can even occur for years later. For the lTGCT a clinical survey and MRT is proposed after 3–6 months after intervention (baseline), followed by annual clinical examination for 3 years, and in case of symptoms MR-imaging. Larger prospective multi-center studies are necessary to confirm these results and recommendations.

Mucin-derived O-glycans supplemented to diet mitigate diverse microbiota perturbations

Microbiota-accessible carbohydrates (MACs) are powerful modulators of microbiota composition and function. These substrates are often derived from diet, such as complex polysaccharides from plants or human milk oligosaccharides (HMOs) during breastfeeding. Host-derived mucus glycans on gut-secreted mucin proteins serve as a continuous endogenous source of MACs for resident microbes; here we investigate the potential role of purified, orally administered mucus glycans in maintaining a healthy microbial community. In this study, we liberated and purified O-linked glycans from porcine gastric mucin and assessed their efficacy in shaping the recovery of a perturbed microbiota in a mouse model. We found that porcine mucin glycans (PMGs) and HMOs enrich for taxonomically similar resident microbes. We demonstrate that PMGs aid recovery of the microbiota after antibiotic treatment, suppress Clostridium difficile abundance, delay the onset of diet-induced obesity, and increase the relative abundance of resident Akkermansia muciniphila. In silico analysis revealed that genes associated with mucus utilization are abundant and diverse in prevalent gut commensals and rare in enteric pathogens, consistent with these glycan-degrading capabilities being selected for during host development and throughout the evolution of the host-microbe relationship. Importantly, we identify mucus glycans as a novel class of prebiotic compounds that can be used to mitigate perturbations to the microbiota and provide benefits to host physiology.

Human milk oligosaccharide categories define the microbiota composition in human colostrum

Human milk oligosaccharides (HMOs) are structurally diverse unconjugated glycans with a composition unique to each lactating mother. While HMOs have been shown to have an impact on the development of infant gut microbiota, it is not well known if HMOs also already affect milk microbial composition. To address this question, we analysed eleven colostrum samples for HMO content by high-pressure liquid chromatography and microbiota composition by quantitative PCR. Higher total HMO concentration was associated with higher counts of Bifidobacterium spp. (ρ=0.63, P=0.036). A distinctive effect was seen when comparing different HMO groups: positive correlations were observed between sialylated HMOs and Bifidobacterium breve (ρ=0.84, P=0.001), and non-fucosylated/non-sialylated HMOs and Bifidobacterium longum group (ρ=0.65, P=0.030). In addition to associations between HMOs and bifidobacteria, positive correlations were observed between fucosylated HMOs and Akkermansia muciniphila (ρ=0.70, P=0.017), and between fucosylated/sialylated HMOs and Staphylococcus aureus (ρ=0.75, P=0.007). Our results suggest that the characterised HMOs have an effect on specific microbial groups in human milk. Both oligosaccharides and microbes provide a concise inoculum for the compositional development of the infant gut microbiota.

Galectin-3 binding protein in human preterm infant umbilical cord plasma

BACKGROUND

Galectin-3 binding protein (Gal3BP) is a glycoprotein isolated in colostrum that may be an immunologically active component with effects on the neonatal immune system. This compound has been found in the blood of term newborn infants, but has not been studied in preterm infants.

OBJECTIVE

Compare umbilical cord plasma Gal3BP concentration between preterm and term infants.

STUDY DESIGN

Observational study of mother-infant pairs consented at UCSD Medical Center comparing umbilical cord plasma Gal3BP concentration in preterm and term infants. Umbilical cord plasma was collected at birth and stored at -80°C before Gal3BP analysis by ELISA. This study was powered to evaluate differences in preterm and term infant Gal3BP concentration. The secondary aim was to determine the effect of maternal and infant clinical factors on Gal3BP concentration.

RESULTS

A total of 64 preterm and 30 term umbilical cord plasma samples were analyzed. By univariate analysis, Gal3BP concentration was elevated in the setting of prematurity, maternal diabetes, antenatal steroid exposure, and increasing maternal parity (p <  0.05); and decreased in chorioamnionitis (p = 0.03). Using a multiple linear regression model prematurity, chorioamnionitis and maternal diabetes remained significant.

CONCLUSIONS

Umbilical cord plasma Gal3BP concentration is elevated in prematurity. This may reflect inflammatory states in infant and mother, but further study is warranted.

The Hydrophobic Mannose Derivative 1B6TM Efficiently Inhibits Borna Disease Virus in Vitro

α-D-Mannnose occupies the terminal position on the N-linked carbohydrate side chain of BDV-specific gp17 (Stoyloff et al., 1994). A hydrophobic derivative of this sugar residue, the 1-0-benzyl-6-0-trityl-α-D-mannnopyranoside (1B6TM), showed a potent and selective inhibition of BDV-replication in vitro, using a range of host-cell/virus systems. When tested in comparison with the unmodified sugar, 1B6TM inhibited the infection in a dose-dependent manner up to 100% without effecting cell viability. After removal of the compound, the antiviral effect remained for several hours. These results suggest that simple modified carbohydrate molecules of BDV-specific sugar residues are able to interfere with virus replication.

Proteomics reveal energy metabolism and mitogen-activated protein kinase signal transduction perturbation in human Borna disease virus Hu-H1-infected oligodendroglial cells

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A human strain of BDV (BDV Hu-H1) was used to infect human oligodendroglial cells (OL cells).

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Energy metabolism was the most significantly altered pathway in BDV Hu-H1-infected OL cells.

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The Raf/MEK/ERK signaling cascade was significantly perturbed in BDV Hu-H1-infected OL cells.

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BDV Hu-H1caused constitutive activation of the ERK1/2 pathway, but cell proliferation was down-regulated at the same time.

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BDV Hu-H1 manages to down-regulate cell proliferation, in the presence of activated but not translocated ERK–RSK complex.

Borna disease virus (BDV) is a neurotropic, non-cytolytic RNA virus which replicates in the cell nucleus targeting mainly hippocampal neurons, but also astroglial and oligodendroglial cells in the brain. BDV is associated with a large spectrum of neuropsychiatric pathologies in animals. Its relationship to human neuropsychiatric illness still remains controversial. We could recently demonstrate that human BDV strain Hu-H1 promoted apoptosis and inhibited cell proliferation in a human oligodendroglial cell line (OL cells) whereas laboratory BDV strain V acted contrariwise. Here, differential protein expression between BDV Hu-H1-infected OL cells and non-infected OL cells was assessed through a proteomics approach, using two-dimensional electrophoresis followed by matrix-assisted laser desorption ionization-time of flight tandem mass spectrometry. A total of 63 differential host proteins were identified in BDV Hu-H1-infected OL cells compared to non-infected OL cells. We found that most changes referred to alterations related to the pentose phosphate pathway, glyoxylate and dicarboxylate metabolism, the tricarboxylic acid (TCA) cycle, and glycolysis /gluconeogenesis. By manual querying, two differential proteins were found to be associated with mitogen-activated protein kinase (MAPK) signal transduction. Five key signaling proteins of this pathway (i.e., p-Raf, p-MEK, p-ERK1/2, p-RSK, and p-MSK) were selected for Western blotting validation. p-ERK1/2 and p-RSK were found to be significantly up-regulated, and p-MSK was found to be significantly down-regulated in BDV Hu-H1-infected OL cells compared to non-infected OL cell. Although BDV Hu-H1 constitutively activated the ERK–RSK pathway, host cell proliferation and nuclear translocation of activated pERK in BDV Hu-H1-infected OL cells were impaired. These findings indicate that BDV Hu-H1 infection of human oligodendroglial cells significantly perturbs host energy metabolism, activates the downstream ERK–RSK complex of the Raf/MEK/ERK signaling cascade, and disturbs host cell proliferation possibly through impaired nuclear translocation of pERK, a finding which warrants further research.

Human milk oligosaccharides and their potential benefits for the breast-fed neonate

Human milk oligosaccharides (HMO), unconjugated complex carbohydrates that are highly abundant in human milk but not in infant formula, have recently received much attention due to their potential benefits for the breast-fed neonate. While it is becoming evident that HMO structure determines their specific function, understanding the metabolic fate of ingested HMO is key in assessing their biological roles. Remarkably little is known about how, when and where they are metabolized. HMO have long been regarded as metabolically "inert" to the host, as significant amounts are excreted with the fe-ces. HMO reach the colon intact where their prebiotic effects promote healthy gut colonization. HMO can also function as soluble decoy receptors and block adhesion of microbial pathogens to epithelial surfaces. Local effects at the mucosal lining include differential cell responses or modulation of the innate immune system. A small percentage of HMO is believed to be absorbed intact in the small intestine and later excreted with the urine, which opens speculations on possible systemic effects, e.g. in the immune system or in the context of neuronal development. Oligosaccharides currently added to infant formula are structurally different from HMO and therefore most likely not functionally equivalent. Selected "authentic" HMO might soon become available for the supplementation of infant formula, but additional preclinical and clinical studies are required to demonstrate efficacy. This review provides an overview about the structural and functional properties of HMO with emphasis on recent findings in metabolism studies.

No evidence of endemic Borna disease virus infection in Australian horses in contrast with endemic infection in other continents

Borna disease virus (BDV) is a unique RNA virus that is a cause of neurological disease in horses, sheep and cats. The finding that BDV also infects humans has raised concern related to the impact of infection with this virus. The extent to which BDV may be endemic in geographical regions outside Europe is of interest in management of international movement of animals including horses. Sera from Australian horses (N = 553) sampled in Sydney, New South Wales (NSW), were analysed for BDV antigen, circulating immune complexes (CICs), and antibodies by monoclonal antibody-based ELISAs. One-tenth of the samples were investigated by further antibody tests, namely immunofluorescence (IFA) and a peptide ELISA, as well as for BDV RNA. The study revealed a very low frequency of serological markers that may be associated with exposure to BDV in Australian horses from NSW with a few sera (0.7%) displaying low range positive results in the CIC assay, and no detectable BDV RNA. This pattern is inconsistent with endemic BDV infection and strongly contrasts with the pattern of endemic infection, particularly in Europe.

Borna disease virus-specific circulating immune complexes, antigenemia, and free antibodies--the key marker triplet determining infection and prevailing in severe mood disorders

Borna disease virus (BDV), a unique genetically highly conserved RNA virus (Bornaviridae; Mononegavirales), preferentially targets neurons of limbic structures causing behavioral abnormalities in animals. Markers and virus in patients with affective disorders and schizophrenia have raised worldwide interest. A persistent infection was suggestive from follow-up studies, but inconstant detectability weakened a possible linkage.This study for the first time discloses that detection gaps are caused by BDV-specific circulating immune complexes (CIC), and their interplay with free antibodies and plasma antigens (p40/p24). Screening 3000 sera each from human and equine patients over the past 4 years by new enzyme immunoassays (EIAs) revealed that BDV-CICs indicate 10 times higher infection rates (up to 30% in controls, up to 100% in patients) than did previous serology. Persistence of high amounts of CICs and plasma antigens correlates with severity of depression. Even BDV RNA could be detected in plasma samples with strong antigenemia. Our discovery not only explains the course of persistent infection, but offers novel easy-to-use diagnostic tools by which new insights into BDV-related etiopathogenesis of disease and epidemiology are possible.

Neutralization of borna disease virus depends upon terminal carbohydrate residues (alpha-D-man, beta-D-GlcNAc) of glycoproteins gp17 and gp94

Borna disease virus (BDV) is an enveloped, nonsegmented, negative-stranded RNA virus that causes infections of the brain in a wide range of animal species and man. The third open reading frame codes for a protein of 17 kD (gp17) that is N-glycosylated and contains terminal alpha-D-mannose and N-acetyl-beta-D-glucosamine residues. Rat sera raised against these carbohydrates (anti-sugar antisera) show high in vitro neutralization activity and were capable of precipitating BDV. The neutralizing capacity of sera derived from experimentally BDV-infected rabbits, in turn, decreased after adsorption with those carbohydrates. They partially inhibited infection of primary young rabbit brain cells in a dose-dependent manner. Furthermore, the anti-sugar antisera recognized a second virus-specific glycoprotein with an apparent molecular mass of 94 kD (gp94), providing indirect evidence that gp94 is involved in virus adsorption and/or entry into cells. Neutralization of BDV comprises a complex event and, as shown for the first time, involves the carbohydrate residues of both glycoproteins of BDV.

Borna disease virus: new aspects on infection, disease, diagnosis and epidemiology

A 'disease of the head' affecting horses, as described in the 17th Century is now known as Borna disease. Research over the past 100 years has established that the aetiological agent, Borna disease virus (BDV), is an unsegmented, single- and negative-stranded, enveloped ribonucleic acid (RNA) virus which represents the family Bornaviridae in the order Mononegavirales. The virus exists world-wide in horses, sheep, cattle, cats, dogs and ostriches. The infection can be fatal, but the majority of carriers are persistently infected without showing symptoms. The association with psychiatric diseases in humans led to an international explosion of research on BDV, with centres established in Germany, the United States of America and Japan. Experimental infections of tree shrews and rats served to examine the effects of persistent and overt disease, most excitingly, virus-induced behavioural changes, and emotional and learning deficits. This 'emerging' virus infection shows complex pathogenetic mechanisms in the nervous system, but also spreads through myelo-monocytic cells. Diagnosis can be made serologically, but detection of antigen markers in peripheral white blood cells, combined with nucleic acid amplification is more profitable. Comparative RNA studies reveal an unusually high genetic homology of viruses. Isolates recovered from humans and equines suggest species-specificity. Vaccination is not an advisable strategy, but antiviral therapy, especially with amantadine sulphate, promises efficacy in human mood disorders, and is effective in vitro. Infections with BDV follow a vulnerability principle to cause disease. Although cross-species transmission of this commensal virus has not been proven, zoonotic aspects of BDV should be carefully considered.

Amantadine in depressive patients with Borna disease virus (BDV) infection: an open trial

OBJECTIVE

Originally introduced into pharmacotherapy as an antiviral compound, amantadine was shown to also have multiple pharmacological eftfects on the central nervous system. In addition. only a few studies reported on certain antidepressive properties of amantadine. This effect was highlighted by the discovery of its antiviral effect on Borna disease virus (BDV), which is hypothesized to be an etiopathogenetic factor to subtypes of affective disorders. Therefore, the therapeutical use of amantadine in BDV-infected depressive patients was investigated.

METHODS

In this open trial, amantadine was added to antidepressive and or mood-stabilizing compounds treating BDV-infected depressed patients (n = 25) with bipolar or major depressive disorders. Amantadine was given twice a day (100-300 mg/day) for a mean of 11 weeks. Antidepressive treatment response was measured on the Hamilton rating scale for depression (HAM-D) and/or with an operationalized diagnostic criteria system (OPCRIT: version 3.31). Virological response was measured by expression of BDV infection parameters in blood samples.

RESULTS

The overall response rate of the amantadine augmentation in the BDV-infected patients with regard to depressive symptoms was 68% after a mean of 2.9 weeks of treatment. Bipolar I patients improved faster and did not show any following hypomania. In addition, the decrease of depression tended to correspond with the decrease in viral activity.

CONCLUSION

Amantadine appears to show a remarkable antidepressive efficacy in BDV-infected depressive patients. The antidepressive effect in this open trial appeared to be comparable to standard antidepressives, possibly being a result of its antiviral effect against BDV as a potentially relevant etiopathogenetic factor in these disorders.

Amantadine revisited: an open trial of amantadinesulfate treatment in chronically depressed patients with Borna disease virus infection

Amantadinesulfate is a well known substance which has proven useful in the treatment and prophylaxis of viral infections, in treating symptoms of Parkinson's disease, cocaine dependence, and apathy in multiple sclerosis. It has also been reported as having mild antidepressive effects not sufficient to warrant its use as an antidepressant. Striking antidepressive effects in some patients have been attributed to its antiviral activity against human Borna disease virus (BDV) infection which is frequently seen in patients with depressive episodes. In this 8 to 12 week open study of oral amantadine in 30 depressed patients with various states of BDV infection we found a significant antidepressive response in 19 of 30. Peripheral BDV antigen indicating acute infection was cleared in both responders and non-responders, but only in responders peripheral infection was significantly reduced.

Activated Borna disease virus in affective disorders

BACKGROUND

Borna disease virus (BDV) is an animal pathogen that causes behavioral changes in animals. Previous studies have found a high prevalence of serum antibodies as well as Borna disease viral antigens (BDVAGs) and RNA in the white blood cells of psychiatric patients, especially those with affective disorders. The present study attempts to offer a better description of the BDVAG cohort using clinical parameters.

METHODS

The prevalence of BDVAG was examined in the peripheral mononuclear leukocytes of patients with a major depressive episode. A subgroup of patients underwent further clinical analysis.

RESULTS

In this pilot study, at least, there was a significant difference in the prevalence of BDVAG between psychiatric inpatients with a major depressive episode and control individuals. It also appeared that BDVAG is more frequent in patients with recurrent major depression or bipolar disorder than in those with any other psychiatric disorder studied. The number of previous depressive episodes, as well as symptoms involving fatigue and concentration difficulties were positively related to BDVAG.

CONCLUSIONS

The high rate of BDVAG, especially in fatigued patients with recurrent major depression or bipolar disorder, may be a nonspecific aspect of immunosuppression. The question remains whether this neurotropic virus may contribute to the pathogenesis of some types of affective disorder.

A viro-psycho-immunological disease-model of a subtype affective disorder

Borna Disease Virus (BDV) infections are widespread in animal species. This neurotropic, negative and single-stranded enveloped RNA virus spreads via axonal and transsynaptic pathways quite specifically into olfactoric and limbic structures. The symptoms in BDV-infected animals range from unapparent or subtle clinical manifestations to fatal neurological disorders. The severe and fulminant course of the infection, which is often accompanied by neurobehavioral and "emotional" disturbances, occurs sporadically and, at least in experimentally infected animals (rats), is thought to be mediated by immunopathology. Increases in serum-BDV antibodies have also been detected in neuropsychiatric patients. In addition, viral antigen and viral RNA have been observed in acutely ill major depressive patients, leading to the conclusion that BDV was causally related to psychiatric disorders, in particular to affective disorders. A number of studies have meanwhile furnished evidence of abnormal immune functions in mentally ill patients. In addition, stress has been shown to decrease immune responses to viral infections. On the basis of these findings it is hypothesized that human BDV infection represents a co-factor in the development or course of psychiatric diseases. Stress may cause immunosuppression and thus induce activation of persisting BDV in the limbic system, resulting in an inflammatory reaction of these structures. These neuropathological changes might influence the serotonergic or dopaminergic neurotransmitter systems. In addition, a specific affinity of BDV structural elements for aspartate and glutamate receptors in the hippocampal formation might directly induce an imbalance of these transmitter system interactions, causing affective and behavioral disturbances. The possible interactions between stress-induced immunosuppression, BDV infection and affective disorders in humans, and the theoretical and clinical aspects of this concept are discussed.

The neuropathogenesis of Borna disease virus infections

The unique genetic and biological properties of this small enveloped RNA virus indicate that Borna disease virus (BDV) is an evolutionary old pathogen. It appears perfectly adapted to persist inside the limbic system, a most delicate and sensitive old area of the mammalian brain involved in the control of mood, behavior, and memory. In many infected individuals, BDV remains a commensal during their lifetime. In a minority of vulnerable subjects, BDV becomes frequently activated, leading to episodes of distinct, more or less severe disturbances of information processing, behavioral and mood alterations. BDV research in humans is anticipated to initiate new insights into the interplay of exogenous and endogenous factors governing mood disorders. In nature BDV preferentially behaves as a neurotropic virus, but may latently and/or persistently infect cells of the reticuloendothelial system. This has been shown to be of great diagnostic importance, because now BDV 'footprints' can be followed in vivo in animals and man. BDV, which has long been considered as a classical animal virus, is present in humans, and has been found to be associated with some defined psychiatric disorders in particularly vulnerable individuals. An interaction of BDV proteins with neurotransmitter activities is plausible in the light of experimental animal data. Interference with normal behavior and the influence on mood and cognitive functions as demonstrated in animals and assumed in humans require extensive future research on the molecular etiopathogenesis. Aside from these clinical aspects, BDV is an unusual agent with outstanding features, namely replication in the nucleus of its target cells by an elusive, partially unknown mechanism, showing no cytopathogenicity or disturbance of vital cell functions, but altering luxury functions, and with a lifelong persistence giving rise to periods of long latency and short activation.

Clinical similarities and close genetic relationship of human and animal Borna disease virus

Borna disease virus (BDV) is the prototype genus of a new family, Bornaviridae, within the order Mononegavirales. BDV naturally infects animals and man. The symptomatology in animals ranges from subclinical infection to rare cases of encephalitis. Asymptomatic infection seemed more frequent than expected, based on antibody data from 100 healthy horses derived from different stables with a history of diseased cases (30-40% carriers). Likewise, phasic episodes of a neurobehavioral syndrome followed by recovery were much more common than fatal neurologic disease. They were paralleled by expression of BDV antigens (N-protein p40, P-protein p24) and RNA transcripts in peripheral blood mononuclear cells, indicating viral activation. Representative longitudinal studies showed that episodes of depressive illness in humans as well as apathetic phases in infected horses were accompanied by antigen expression and followed a similar clinical course. After recovery, BDV antigen disappeared. This temporal congruence, together with the recent isolation of infectious BDV from such patients, points to a contributory role of this virus in human affective disorders. Successful amelioration of BDV-induced neurobehavioral disease in horses with antidepressants applied in psychiatry, supported a common viral pathomechanism, involving reversible disturbances of the neurotransmitter network in the limbic system. Sequences of genetic material amplified from infected animal tissue and human PBMCs revealed a close interspecies relationship and high sequence conservation of the BDV genome. In human BDV isolates, however, single unique mutations were prominent in four genes. This finding supports the hypothesis that despite of high genomic conservation, species-specific genotypes may be definable, provided the sequences are derived from RNA of infectious virus.

The glycosylated matrix protein of Borna disease virus is a tetrameric membrane-bound viral component essential for infection

Borna disease virus (BDV) is representative of the family of Bornaviridae in the order Mononegavirales (negative-stranded, non-segmented, enveloped RNA viruses). It is the causal agent for Borna disease, characterized as an encephalomyelitis (typical form) in a wide variety of domestic animals (from rodents to birds). Recent information shows the involvement of BDV in the pathogenesis of some human psychiatric disorders. The 8.9-kb viral antigenome codes for five major ORF. The third ORF codes for a 16-kDa protein (matrix protein) that is posttranslationally modified, yielding an N-linked glycoprotein. Our data show that the glycosylated matrix protein exists as a stable tetrameric structure detectable either by electrospray ionization or matrix-assisted laser-desorption ionization mass spectrometry. Under native conditions, the tetramer, with a relative molecular mass of 68 kDa, was isolated from a sediment-free brain suspension of a BDV-infected horse. The 68-kDa entity is stable in the presence of ionic and nonionic detergents but dissociates into subunits when heated. We found that the tetrameric matrix protein inhibits in vitro BDV infection in a dose-dependent manner. In contrast to inhibition of BDV infection with hydrophobic carbohydrate derivatives and protein-bound glycoconjugates, the glycosylated matrix protein is a very potent inhibitor of BDV infection, indicating that this protein represents an essential virus-specific membrane component for viral attachment.

Neurological disease and encephalitis in cats experimentally infected with Borna disease virus

Barrier-bred cats were inoculated intracerebrally with either the rabbit-adapted Borna disease virus (BDV) strain V or a newly isolated feline BDV, obtained from a cat with natural staggering disease (SD). Three out of eight inoculated cats developed neurological signs and non-suppurative encephalitis; all three recovered from the acute stage of disease. Sero-conversion and the development of neutralizing antibodies occurred in all of the virus-inoculated cats. In addition, cats inoculated with feline BDV showed an early peripheral T cell response not present in cats inoculated with BDV strain V, suggesting that the feline virus exerted a more vigorous effect on the immune system. Using immunohistochemistry and a reverse transcriptase-polymerase chain reaction assay, BDV-specific antigen and nucleic acid could be demonstrated in brain samples from each cat with encephalitis, showing that incomplete viral clearance was probably responsible for the maintenance of inflammation. The successful induction of neurological signs and encephalitis in one cat infected with feline BDV, together with the detection of BDV-specific antigen and nucleic acid in the brain, provides strong evidence for the notion that BDV is the etiological agent behind feline SD.

Sequence characterization of human Borna disease virus

Borna disease virus (BDV) causes a central nervous system disease in several vertebrate animal species, which is manifest by behavioral abnormalities. Seroepidemiologic data suggest that BDV might infect humans, possibly being associated with certain mental disorders. This is further supported by the detection of both BDV-specific antigens and RNA sequences in peripheral blood mononuclear cells (PBMCs) of psychiatric patients. For the first time the sequence characterization of human BDV is documented here. BDV was recovered by co-cultivation techniques from the PBMCs of three hospitalized psychiatric patients. BDV was unequivocally identified based on sequence identification of BDV open reading frames (ORFs) p24, p16 and p56, as well as of the predicted catalytic domain of the BDV L polymerase. Each human BDV isolate had an unique sequence, but they displayed a high degree of sequence conservation with respect of BDV isolates from naturally infected animals of different species.

First isolates of infectious human Borna disease virus from patients with mood disorders

Borna disease virus (BDV), an unique type of non-segmented negative-stranded enveloped RNA virus, is known as an animal pathogen that causes behavioral diseases in higher vertebrates. Past studies have found antibodies to BDV as well as BDV proteins and genomic transcripts in peripheral blood mononuclear cells (PBMCs) of infected animals and human psychiatric patients. Here, we present the first isolation of infectious BDV from such patients' PBMCs. Isolation attempts were conducted with randomly collected PBMC samples from 33 psychiatric inpatients, by co-cultivation and long-term passaging with a human cell line. BDV isolates were identified by infectivity, analysis of viral antigens, sequencing of one viral gene, and successful infection of animals. Three individual isolates could be recovered. They originated from two bipolar patients with acute depression, and one patient with a chronic obsessive-compulsive disorder. Rescue of human BDV required PBMC samples with strong viral antigen expression, and at least 11 subcultures per sample. Genetic and biological properties point to a close relationship of human and animal strains, but also to the uniqueness of each human isolate. Isolation of BDV from patients with major mood disorders at a time of acute depression strengthens the possibility that BDV infection is one of the environmental factors that contributes to recurrent depressive illnesses in man. These isolates represent the first three defined strains of the infectious human BDV.

Staggering disease in cats: isolation and characterization of the feline Borna disease virus

A Borna disease virus (BDV)-like agent was isolated from the central nervous system (CNS) of cats with a spontaneous non-suppurative encephalomyelitis ('staggering disease'). In contrast to the rabbit-adapted BDV strain V, which can be propagated in several primary and permanent cell cultures, the cat virus grew only in embryonic mink brain cells. Infection of adult Wistar rats with feline brain tissue material did not result in clinical disease during a period of 5 months, nor in growth of infectious virus in the brain. However, using the brain suspension of a newborn rat inoculated with feline brain tissue material, it was possible to induce typical Borna disease (BD) in four adult rats. This indicates a possible adaptation of the cat virus during passages in rats. By the use of an RT-PCR technique, BDV-specific RNA could be detected in a majority of brain samples from diseased cats. BDV-specific antigen was demonstrated in feline CNS samples both by immunohistochemistry and ELISA. However, the amount of BDV RNA and BDV antigen was less in the cats as compared to horses with BD, providing further support for the notion that a distinct feline BDV strain exists.

Presence of antibodies reacting with porcine circovirus in sera of humans, mice, and cattle

Antibodies reacting with porcine circovirus (PCV) were found in sera of humans, mice, and cattle by means of an indirect immunofluorescence assay (IFA) and an ELISA. In man, the highest seroprevalence (23.9% in IFA and 30.2% in ELISA) was found among hospitalized patients with fever of partially unclear etiology. Non-hospitalized "healthy" persons of the former German Democratic Republic showed a significantly higher number of positive sera (IFA = 20%) than blood donors from Berlin-West (IFA = 8.6%). Murine sera reacted positive with PCV in IFA between 12 to 69% in different breeding groups and about 35% of cattle sera were found reactive with PCV in IFA. Double-staining IFAs, immuno-electron microscopy and immunoblotting showed that non-porcine antibodies reacted with PCV structural antigen. Mathematical analysis revealed that in ELISA, non-porcine antibodies reacted specifically with PCV. Loss of binding specificity of non-porcine antibodies in ELISA after storage of sera and lower maximal optical densities obtained at equal titers in ELISA with non-porcine than with porcine sera suggest that antibodies in man, mice and cattle are caused by related species specific viruses sharing antigenic epitopes with PCV.

Distribution of antibodies to porcine circovirus in swine populations of different breeding farms

An enzyme linked immunosorbent assay (ELISA) was developed for mass antibody screening to porcine circovirus (PCV) in pig herds of different age groups and of different husbandries. Infection with PCV was found to be common in all swine herds tested, with only one exception, a herd at a small farm. Statistically, the percentage of PCV negative sera decreased and titer levels increased with increasing age of the pigs. Within individual age groups, differences were found to exist between different husbandries. No correlation was detected between antibody levels and reproductive disorders in the herds.

Borna disease virus genome transcribed and expressed in psychiatric patients

Borna disease virus (BDV) is a neurotropic, negative and single-stranded enveloped RNA virus that persistently infects various domestic animal species. Infection causes disturbances in behaviour and cognitive functions, but can also lead to a fatal neurologic disease. Human infections seemed likely, since serum antibodies were detected in neuropsychiatric patients. Further proof came from our discovery that peripheral blood monocytes carry viral antigens. Here, we present the first data on different viral genomic transcripts in such patients' cells as well as sequence data of transcripts. Both viral markers seem to coincide with acute episodes of mood disorders, thus pointing to a new human virus infection possibly threatening mental health.

Characterization and sequence of a 33-kDa enterohemolysin (Ehly 1)-associated protein in Escherichia coli

The nucleotide sequence of the 2.1-kb EcoRI-AccI fragment of the enterohemolysin (Ehly)-associated plasmid, pEO21, has been determined. A third of this sequence encodes a 29.6-kDa protein, and coincides with the location of Tn1725 insertions which inactivate the production of Ehly. A protein of similar size (33-35 kDa) was found to be produced in large amounts by JM83[pEO21] and found to be immunologically related to the approximately 65-kDa protein made by the parental strain, C3888. DNA sequences coding for the 29.6-kDa protein of phi C3888, now designated Ehly 1, were found only in some enterohemolytic Escherichia coli indicating the existence of multiple, genetically different Ehlys.

Natural Borna disease in domestic animals others than horses and sheep

In 24 cats (Uppsala, Sweden) with neurological signs of "staggering disease" and typical neuropathology, 44% had Borna disease virus (BDV)-specific antibodies. In 173 cat sera (Berlin, Germany) of animals with unknown record, 7% were BDV positive. Out of 24 cats with undefined neurological disorders, 13% were BDV positive. Similarities in staggering disease of cats and Borna disease of horses and sheep suggest related etiological agents.

Biology and neurobiology of Borna disease viruses (BDV), defined by antibodies, neutralizability and their pathogenic potential

Borna disease viruses (BDV) isolated from more than 20 naturally infected horses, 2 sheep and a possible feline isolate were included in these studies. Most of these wild-type viruses were grown in rabbit cells. Specifically rabbit-adapted viruses establish persistent infection in immortalized cell lines of various animal species. Brain-, tissue culture-, and cell-free released viruses could all be neutralized with antibodies from naturally and experimentally infected animals (horse; hamster, rat, rabbit, mouse, and chicken), with highest titres in birds. Splenectomized rabbits, which were subsequently infected with BDV, efficiently produced high titres of neutralizing antibodies. All of the neutralizing sera and cerebrospinal fluids from infected animals inhibited tissue culture spread of BDV. Experimental infection and hyperimmunization induced antibodies directed against the major components of the soluble antigen (60, 40/38, 25 and 14.5 kD proteins). Analysis of the s-antigen complex with these sera and 6 stable monoclonal antibodies revealed that it consists of 40/38 and 25 kD proteins. Although each of these antibodies detected intracellular virus-specific structures they did not recognize outer plasma membrane antigens, showed no cross-reactivity, and had no neutralizing capacity. Unifying pathogenetic concepts of this neurotropic virus and its structural elements are discussed.

Borna disease virus infection and affective disorders in man

Borna Disease virus (BDV) can persistently infect the central nervous system of a broad spectrum of animal species. The clinical course varies from slight behavioral disturbances to a fatal neurological syndrome. In-vivo diagnosis is based on the strong humoral immune response to BDV antigens. Since also human infections could be confirmed by specific antibodies and increased seroprevalence was found in patients with chronic neurologic or immunologic disorders, the contribution of BDV or a BDV-like human variant to syndromes with yet unknown etiology became of great interest. We presented the first data of a current follow-up study on 70 psychiatric patients who were tested three times each after hospitalization. In contrast to previously found low prevalence of antibody carriers by screening (2-4%), we now found 20% positives by follow-up testing. Furthermore, of the randomly selected patients with different psychiatric diagnosis, the highest proportion of antibody carriers was detected among patients with major depression (more than 30%), compared to only 8% among patients with dysthymia (neurotic depression). This led us to hypothesize that Bornavirus infection might contribute somehow to the syndrome of major depressive illness by altering neuronal cells in the limbic system.

Human infections with Borna disease virus: seroprevalence in patients with chronic diseases and healthy individuals

Borna disease virus (BDV) is as yet an unclassified infectious agent which causes a neurologic disease in horses and sheep and is transmissible to other animal species. Human sera were tested for BDV-specific antibodies by immunofluorescence and immunoprecipitation. The sera were collected from three thousand subjects in Europe, the USA, and Africa classified by clinical syndromes/infectious diseases, and from healthy controls. In all three continents, positive serum samples were detected which recognized the major BDV antigen of 38/40 KD present in the nuclei of infected cells. In contrast to 2% of seropositives among the normal population, significantly higher prevalences (13-14%) were present among patients with chronic progressive diseases of the brain and the immune system. In children, antibody frequencies were two to four times higher than in adults. The results suggest a latent infection with BDV in humans leading to low antigen expression in healthy subjects and frequent reactivation events in chronically ill patients.