Neurobrucellosis presenting as leukoencephalopathy: the role of cytotoxic T lymphocytes

Neurobrucellosis (Brucella ceti) in striped dolphins (Stenella coeruleoalba): Immunohistochemical studies on immune response and neuroinflammation

Neurobrucellosis is a shared condition of cetaceans and humans. However, the pathogenesis and immune response in cetacean neurobrucellosis has not been extensively studied. In this multicentric investigation, 21 striped dolphin (Stenella coeruleoalba) neurobrucellosis (Brucella ceti) cases diagnosed over a 10-year period (2012-2022) were retrospectively evaluated. For each case, morphological changes were assessed by evaluating 21 histological parameters. Furthermore, the immunohistochemical expression of Brucella antigen, glial fibrillary acid protein (GFAP), and a selection of inflammatory cell (IBA-1, CD3, and CD20) and cytokine (tumor necrosis factor-alpha [TNF-α], interferon-gamma [IFN-γ], interleukin [IL]-1β, IL-2, and IL-6) markers were investigated. Inflammation of the leptomeninges, ependyma, and/or choroid plexus was lymphohistiocytic, containing macrophages/microglia (IBA-1+), T-cells (CD3+), and B-cells (CD20+) in equal proportion. B-cells occasionally formed tertiary follicles. GFAP expression showed astrocytosis in most cases. Expression of TNF-α, IFN-γ, and IL-2 indicated an intense proinflammatory response, stimulating both macrophages and T-cells. Our results showed that the inflammation and neuroinflammation in neurobrucellosis of striped dolphins mimic human neurobrucellosis and in vitro and in vivo studies in laboratory animals. Cetacean disease surveillance can be exploited to expand the knowledge of the pathogenesis and immunology of infectious diseases, particularly brucellosis, under a One Health approach.

The challenge of managing ischemic stroke in brucellosis: a case report

A 64-year-old woman was admitted to the hospital for sudden weakness in one of her left limbs. The patient was diagnosed with acute ischemic stroke (IS) of undetermined cause and received intravenous thrombolysis. Following thrombolysis, the patient's left limb weakness improved, but she subsequently developed recurrent high fever and delirium. Further diagnostic tests revealed that she had been infected with Brucella melitensis. The patient showed significant improvement during anti-infection treatment for Brucellosis and secondary prevention treatment for IS. However, her condition unexpectedly worsened on the 44th day after admission due to a hemorrhagic stroke (HS), which required an urgent craniotomy. Immunohistochemical analysis of the hematoma sample collected during the operation showed the presence of CD4+ and CD8+ T lymphocytes surrounding the blood vessels. This case highlights the unique challenge of managing IS in brucellosis and sheds light on the potential role of T lymphocytes in the immune response related to stroke.

Bystander activation of microglia by Brucella abortus-infected astrocytes induces neuronal death via IL-6 trans-signaling

Inflammation plays a key role in the pathogenesis of neurobrucellosis where glial cell interactions are at the root of this pathological condition. In this study, we present evidence indicating that soluble factors secreted by Brucella abortus-infected astrocytes activate microglia to induce neuronal death. Culture supernatants (SN) from B. abortus-infected astrocytes induce the release of pro-inflammatory mediators and the increase of the microglial phagocytic capacity, which are two key features in the execution of live neurons by primary phagocytosis, a recently described mechanism whereby B. abortus-activated microglia kills neurons by phagocytosing them. IL-6 neutralization completely abrogates neuronal loss. IL-6 is solely involved in increasing the phagocytic capacity of activated microglia as induced by SN from B. abortus-infected astrocytes and does not participate in their inflammatory activation. Both autocrine microglia-derived and paracrine astrocyte-secreted IL-6 endow microglial cells with up-regulated phagocytic capacity that allows them to phagocytose neurons. Blocking of IL-6 signaling by soluble gp130 abrogates microglial phagocytosis and concomitant neuronal death, indicating that IL-6 activates microglia via trans-signaling. Altogether, these results demonstrate that soluble factors secreted by B. abortus-infected astrocytes activate microglia to induce, via IL-6 trans-signaling, the death of neurons. IL-6 signaling inhibition may thus be considered a strategy to control inflammation and CNS damage in neurobrucellosis.

Innate Lymphoid Cells and Interferons Limit Neurologic and Articular Complications of Brucellosis

Brucellosis is a globally significant zoonotic disease. Human patients with brucellosis develop recurrent fever and focal complications, including arthritis and neurobrucellosis. The current study investigated the role of innate lymphoid cells (ILCs) in the pathogenesis of focal brucellosis caused by Brucella melitensis. After footpad infection, natural killer cells and ILC1 cells both limited joint colonization by Brucella. Mice lacking natural killer cells, and in particular mice lacking all ILCs, also developed marked arthritis after footpad infection. Following pulmonary infection, mice lacking adaptive immune cells and ILCs developed arthritis, neurologic complications, and meningitis. Adaptive immune cells and ILCs both limited colonization of the brain by Brucella following pulmonary infection. Transcriptional analysis of Brucella-infected brains revealed marked up-regulation of genes associated with inflammation and interferon responses, as well as down-regulation of genes associated with neurologic function. Type II interferon deficiency resulted in colonization of the brain by Brucella, but mice lacking both type I and type II interferon signaling more rapidly developed clinical signs of neurobrucellosis, exhibited hippocampal neuronal loss, and had higher levels of Brucella in their brains than mice lacking type II interferon signaling alone. Collectively, these findings indicate ILCs and interferons play an important role in prevention of focal complications during Brucella infection, and that mice with deficiencies in ILCs or interferons can be used to study pathogenesis of neurobrucellosis.

Pediatric neurobrucellosis: a systematic review with case report

Pediatric neurobrucellosis represents a common anthropozoonosis in endemic areas but only anecdotal reports are available till date. Using appropriate search terms in the database platforms of MEDLINE, SCOPUS and Web of Sciences, we performed a systematic review of all the cases of pediatric neurobrucellosis published in the medical literature till date, in the light of a case report. The protocol was registered under PROSPERO (CRD42022333907). Our search strategy yielded 187 citations of which 51 citations were included. A total of 119 cases were reviewed. Of these cases, eight of them had insufficient data. The most common presentation was meningitis with or without encephalitis (n = 79, 71.2%). A high prevalence of cranial neuropathies (n = 22, 20.7%) was observed in the pediatric population in which abducens palsy was the most common (n = 9, 8.1%). Diagnosis was based on multimodal investigations including standard agglutination test (n = 44, 39.6%), Rose Bengal test (n = 37, 33.3%), blood culture (n = 23, 20.7%), serology (n = 20, 18.0%) and cerebrospinal fluid (CSF) culture (n = 11, 9.9%). Rifampicin-based triple drug regimen was the most commonly employed (83/102, 81.4%). Pediatric neurobrucellosis was associated with greater frequency of sequalae (5.4%), deafness (2.7%) and mortality (2.7%), when compared to that of general population. Neurobrucellosis mimics neuro-tuberculosis in various aspects. The review highlights several unique aspects of this entity in children. A high index of suspicion can ensure prompt diagnosis, timely initiation of management and favorable outcomes.

Case report: Revealing a special and rare autoimmune GFAP astrocytopathy in the spinal cord succeeding Neurobrucellosis infection

Brucellosis, a zoonosis, can cause an inflammatory response in most organs and continues to be a public health problem in some endemic areas, whereas neurobrucellosis is a morbid form of brucellosis that affects the central nervous system (CNS) with poor prognosis. Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is an autoimmune disease, and there have been no reports of a Brucella infection, leading to GFAP astrocytopathy. We report the case of a patient with a positive and high level of GFAP antibodies in the cerebrospinal fluid (CSF), following a Brucella infection. Although this patient did not show any responsible lesions in the diffusion sequence of the magnetic resonant imaging (MRI) scan, we found an evidence of thoracolumbar (T12) involvement on fluorodeoxyglucose (FDG) positron emission tomography (PET). The symptoms of spinal cord involvement were only partly relieved after initial treatment [doxycycline (0.1 g Bid) and rifampicin (0.6 g Qd) for 6 weeks]; however, they markedly improved after the subsequent immunosuppressive therapy [intravenous methylprednisolone (1,000 mg for 3 days)], followed by a 50% reduction from the preceding dose after 3 days, and subsequently, oral prednisone tablets (60 mg/day) was started, which was then gradually tapered [reduced to 10 mg/day every 1–2 weeks)]. The positive response to immunosuppressive therapy and treatment outcome strongly indicated the presence of an autoimmune neurological disease probably triggered by some infectious factors. Therefore, our findings reveal that a Brucella infection is one of the causes of autoimmune GFAP astrocytopathy, and when this infection is difficult to be identified by regular MRI, FDG PET can be used as a supplementary method for diagnosis and treatment.

Neurobrucellosis: Brief Review

BACKGROUND

Brucella are small, nonmotile, intracellular, and aerobic gram-negative bacteria. Of the 10 species that currently form the genus Brucella, 5 were shown to be pathogenic in humans.

REVIEW SUMMARY

The epidemiology, clinical manifestations, diagnosis and imaging, and treatment of neurobrucellosis will be reviewed.Brucellosis's transmission to humans occurs by direct contact with contaminated animals. Older patients are at increased risk of nervous system involvement in brucellosis. Brucella spp. can lead to central nervous system involvement through direct damage via invasion of neural tissue or indirect damage caused by endotoxins or immune inflammatory reactions elicited by the presence of the bacteria in the body. Patients can have general nonspecific symptoms in addition to neurological and psychiatric symptoms. There are 4 diagnostic criteria for the diagnosis of neurobrucellosis, which include signs and symptoms suggestive of neurobrucellosis, a positive finding of Brucella spp. in the cerebrospinal fluid (CSF), and/or a positive titer of antibodies targeting brucella in the CSF, lymphocytosis with high protein levels and low glucose levels in CSF, and imaging findings (either cranial magnetic resonance imaging or computed tomography) peculiar to neurobrucellosis. For the treatment, a combined therapy is favored over monotherapy for the eradication of Brucella. Moreover, a multirouted therapy has been associated with increased treatment efficacy. The prognosis of neurobrucellosis is dependent on patients' clinical presentation: brucellar meningitis is associated with a good prognosis, whereas diffuse central nervous system involvement is associated with the development of long-term sequelae.

CONCLUSIONS

Neurobrucellosis affects patients globally and in endemic areas. Neurologists should familiarize themselves with its clinical presentation, diagnosis, and treatment to provide optimal care for their patients.

Cervical Epidural Abscess due to Brucella Treated with Decompression and Instrumentation: A Case Report and Review of Literature

Brucella is caused by a Gram-negative bacillus and is a common disease in endemic areas where people are in close contact with animals and dairy products, but brucellar cervical epidural abscess is rare. We describe a rare case of a C5–6 brucellar epidural abscess in a veterinary doctor who was treated with decompression and instrumentation. We also review the cases of cervical brucellar epidural abscess treated with instrumentation in the literature.

CCR5 and CCR5Δ32 in bacterial and parasitic infections: Thinking chemokine receptors outside the HIV box

The CCR5 molecule was reported in 1996 as the main HIV-1 co-receptor. In that same year, the CCR5Δ32 genetic variant was described as a strong protective factor against HIV-1 infection. These findings led to extensive research regarding the CCR5, culminating in critical scientific advances, such as the development of CCR5 inhibitors for the treatment of HIV infection. Recently, the research landscape surrounding CCR5 has begun to change. Different research groups have realized that, since CCR5 has such important effects in the chemokine system, it could also affect other different physiological systems. Therefore, the effect of reduced CCR5 expression due to the presence of the CCR5Δ32 variant began to be further studied. Several studies have investigated the role of CCR5 and the impacts of CCR5Δ32 on autoimmune and inflammatory diseases, various types of cancer, and viral diseases. However, the role of CCR5 in diseases caused by bacteria and parasites is still poorly understood. Therefore, the aim of this article is to review the role of CCR5 and the effects of CCR5Δ32 on bacterial (brucellosis, osteomyelitis, pneumonia, tuberculosis and infection by Chlamydia trachomatis) and parasitic infections (toxoplasmosis, leishmaniasis, Chagas disease and schistosomiasis). Basic information about each of these infections was also addressed. The neglected role of CCR5 in fungal disease and emerging studies regarding the action of CCR5 on regulatory T cells are briefly covered in this review. Considering the "renaissance of CCR5 research," this article is useful for updating researchers who develop studies involving CCR5 and CCR5Δ32 in different infectious diseases.

Spinal brucellosis

Spinal involvement in human brucellosis is a common condition and a significant cause of morbidity and mortality, particularly in endemic areas, because it is often associated with therapeutic failure. Most chronic brucellosis cases are the result of inadequate treatment of the initial episode. Recognition of spinal brucellosis is challenging. Early diagnosis is important to ensure proper treatment and decrease morbidity and mortality. Radiologic evaluation has gained importance in diagnosis and treatment planning, including interventional procedures and monitoring of all spinal infections.

Brucella abortus induces the secretion of proinflammatory mediators from glial cells leading to astrocyte apoptosis

Central nervous system (CNS) invasion by bacteria of the genus Brucella results in an inflammatory disorder called neurobrucellosis. In this study we present in vivo and in vitro evidence that B. abortus and its lipoproteins activate the innate immunity of the CNS, eliciting an inflammatory response that leads to astrogliosis, a characteristic feature of neurobrucellosis. Intracranial injection of heat-killed B. abortus (HKBA) or outer membrane protein 19 (Omp19), a B. abortus lipoprotein model, induced astrogliosis in mouse striatum. Moreover, infection of astrocytes and microglia with B. abortus induced the secretion of interleukin (IL)-6, IL-1beta, tumor necrosis factor (TNF)-alpha, macrophage chemoattractant protein-1, and KC (CXCL1). HKBA also induced these inflammatory mediators, suggesting the involvement of a structural component of the bacterium. Accordingly, Omp19 induced the same cytokine and chemokine secretion pattern. B. abortus infection induced astrocyte, but not microglia, apoptosis. Indeed, HKBA and Omp19 elicited not only astrocyte apoptosis but also proliferation, two features observed during astrogliosis. Apoptosis induced by HKBA and L-Omp19 was completely suppressed in cells of TNF receptor p55-/- mice or when the general caspase inhibitor Z-VAD-FMK was added to cultures. Hence, TNF-alpha signaling via TNF receptor (TNFR) 1 through the coupling of caspases determines apoptosis. Our results provide proof of the principle that Brucella lipoproteins could be key virulence factors in neurobrucellosis and that astrogliosis might contribute to neurobrucellosis pathogenesis.

Magnetic resonance spectroscopy features of normal-appearing white matter in patients with acute brucellosis

We aimed to evaluate whether the subtle metabolic cerebral changes are present in normal-appearing white matter on conventional MRI, in patients with acute brucellosis, by using MR spectroscopy (MRS). Sixteen patients with acute brucellosis and 13 healthy control subjects were investigated with conventional MRI and single-voxel MRS. Voxels were placed in normal-appearing parietal white matter (NAPWM). N-Acetyl aspartate (NAA)/creatine (Cr) and choline (Cho)/Cr ratios were calculated. There was no significant difference between the study subjects and the control group in NAA/Cr ratios obtained from NAPWM. However, the Cho/Cr ratios were significantly higher in patients with acute brucellosis compared to controls (p=0.01). MRS revealed metabolic changes in normal-appearing white matter of patients with brucellosis. Brucellosis may cause subtle cerebral alterations, which may only be discernible with MRS. Increased Cho/Cr ratio possibly represents an initial phase of inflammation and/or demyelination process of brucellosis.

Abducens nerve palsy and optic neuritis as initial manifestation in brucellosis

Cranial nerve involvement in brucellosis is rare. We present a case of brucellosis presenting with optic neuritis and abducens nerve palsy on the left side. Cerebrospinal fluid findings indicated Brucella meningitis with high protein count, low sugar level and pleocystosis. In addition, Brucella agglutination test (Wright test) was found to be 1/128 in cerebrospinal fluid. Serum agglutination test for Brucella was also positive at 1/1280. This case was diagnosed as brucellosis involving optic and abducens nerves. The patient was treated by ceftriaxone (intravenous), rifampicin (orally) and doxycycline (orally). Two months later the patient's vision acuity in the left eye had moderately improved and the patient's left abducens palsy had almost disappeared. In conclusion, cranial nerve involvement in brucellosis can have good prognosis if anti-Brucella treatment is undertaken early.

Brucellosis epidemiological and clinical aspects (Is brucellosis a major public health problem in Bosnia and Herzegovina?)

Brucellosis is primarily an animal disease, and in them it passes as an asymptomatic chronic infection. In humans, brucellosis can be acute, sub-acute and/or chronic disease, but its geographical distribution follows the pattern found in animals. After the last war, the first Brucella cases in Bosnia and Herzegovina were reported in 2000, in returnees, owners of donated livestock. The objective of this paper was to address an increased public health problem regarding brucellosis in Bosnia and Herzegovina and to initiate better cooperation among epidemiologists, veterinarians, microbiologists and infectologists and responsible authorities toward elimination and eradication of this severe disease. Retrospective analysis of Brucella case histories and treatment protocols of all the cases hospitalized in Clinic for Infectious Diseases, University of Sarajevo Clinics Center (CCUS) was conducted. All the patients hospitalized between 1 January 2000 and 1 July 2005 were included. The diagnoses were confirmed by laboratory tests, chemo culture or serologically. The Rose Bengal agglutination and ELISA tests were used as laboratory confirmation methods. The number of hospitalized cases over the last 5 years was compared with total number of reported cases in the first 6 months of 2005. The results of this study showed that Brucella infections in humans, compared to other zoonoses, was represented with 11.8%. Brucellosis was the second zoonose in a ranking of zoonotic diseases cases with steady increase in the number of reported cases each year. The number of cases treated in the first 6 months of 2005 already exceeded half of the total number of cases treated in the last 5 years. Human brucellosis is an increasing public health problem in Bosnia and Herzegovina, and it reflects spreading of the same disease in animals. The applied prevention measures have been insufficient, so it is necessary to mobilize all the available resources of human and veterinary medicine, as well as the authorities, microbiological laboratory diagnostics in order to identify foci of epidemics and to try to eliminate and eradicate this complicated disease.

Successful medical treatment of intracranial abscess caused by Brucella spp

An unusual presentation of unilateral cerebellar abscesses due to neurobrucellosis observed in a patient is reported. He gave a history of fever, headache, vomiting and had unilateral cerebellar signs. The abscess was detected on magnetic resonance imaging (MRI) and analysis of cerebrospinal fluid revealed neurobrucellosis. Patient treated by only antibiotics therapy, evolving to complete clinical and radiological resolution, without neurosurgical intervention. We are presenting a case of cerebellar abscess due to neurobrucellosis diagnosed by MRI, treated medically, and had both radiologic and clinical follow-up. We also made a review of the literature concerning the cerebellar abscess due to neurobrucellosis.

Recurrent transverse myelitis following neurobrucellosis: Immunologic features and beneficial response to immunosuppression

The authors report the clinical course and immune system response of a patient with disease-associated recurrent transverse myelitis (TM) following cerebral infection with Brucellosis melitensis. The patient suffered four recurrences of his TM (each at a distinct spinal cord level) over the course of 2 years following his initial presentation, which ultimately progressed to quadriplegia. He had progressively declining cerebrospinal fluid (CSF) brucella antibody titers, suggesting a postinfectious, rather than an infectious, etiology. The authors simultaneously examined the expression of multiple cytokines in the CSF of this patient using cytokine antibody arrays and found a marked elevation of interleukin (IL)-6, IL-8, and macrophage chemoattractant protein (MCP)-1 levels relative to controls. Quantitative enzyme-linked immunosorbent assay (ELISA) analysis of the CSF confirmed a 1700-fold elevation of IL-6 and more modest elevations of IL-8 and MCP-1. IL-6 levels returned to baseline following treatment of the patient with intravenous cyclophosphamide and plasma exchange and the patient experienced a significant and sustained recovery of function.

Spinal Brucellosis with Paraspinal Abscess Formation Treated with CT Guided Percutaneous Abscess Drainage

SUMMARY

Although brucellosis may be present in various systems, osteoarticular brucellosis is a serious complication of human brucellosis. We present two cases of Brucellar spondylitis (BS) having paraspinal abscess with epidural extension. The first case of non-complicated paraspinal abscess was treated effectively with percutaneous abscess drainage and antibrucellar chemotherapy. However, the second case with disseminated BS and multiseptated large abscess did not respond to needle drainage with medical treatment. Because of the persistence and re-growth of the abscess, he was treated with percutaneous catheter drainage using the Seldinger technique. They showed adequate radiological and clinical response to drainage and antibrucellar chemotherapy.