Human neurobrucellosis with intracerebral granuloma caused by a marine mammal Brucella spp

Brucella microti and Rodent-Borne Brucellosis: A Neglected Public Health Threat

Brucellosis is one of the most important zoonoses worldwide, primarily affecting livestock but also posing a serious threat to public health. The major Brucella species are known to cause a feverish disease in humans with various clinical signs. These classical Brucella species are (re-)emerging, but also novel strains and species, some of them transmitted from rodents, can be associated with human infections. As a result of our review on rodent-borne brucellosis, we emphasise the need for more comprehensive surveillance of Brucella and especially Brucella microti in rodent populations and call for further research targeting the ecological persistence of rodent-associated Brucella species in the environment, their epizootic role in wild rodents and their virulence and pathogenicity for wildlife.

The effect of Brucella abortus on glial activation and cell death in adult male rat's hippocampus

A zoonotic disease called brucellosis can cause flu-like symptoms and heart inflammation. The bacteria responsible for this disease can also enter the brain, causing a condition called neurobrucellosis that can result in long-term neurological problems. In this study, researchers aimed to determine the changes in the hippocampal cells of rats infected with Brucella. For the study, 24 adult male albino rats were inoculated with 1 × 106 CFU Brucella abortus 544. The rats were then deeply anesthetized, and their hippocampus samples were taken for stereological, histological, and molecular studies. The results showed that the infected rats had increased microgliosis and astrogliosis. Furthermore, a high level of caspase-3 in their hippocampal tissue indicated their susceptibility to apoptosis. Additionally, there was a decrease in expression of Ki67, which further supported this. Sholl's analysis confirmed a significant failure in glial morphology. The study demonstrated that the pathogen has the ability to destroy the hippocampus and potentially affect its normal physiology. However, more research is needed to clarify various aspects of neurobrucellosis.

Investigations on the Health Status and Infection Risk of Harbour Seals (Phoca vitulina) from Waters of the Lower Saxon Wadden Sea, Germany

Harbour seals (Phoca vitulina) are the most common pinniped species in the Wadden Sea of Schleswig-Holstein, Hamburg and Lower Saxony, Germany. Their numbers have recovered after significant depletion due to viral outbreaks and effects of anthropogenic activities like pollution and habitat disturbance. Within the Wadden Sea National Park of Lower Saxony the harbour seal is protected. As a top predator in the Wadden Sea ecosystem, the harbour seal is a sentinel species for the state of the environment. Between 2015 and 2017, a total of 80 stranded dead harbour seals were collected along the coastline of Lower Saxony and submitted for pathological investigations. Of these, 70 seals were born in the same year (0-7 months, age group 1) and eight in the previous year (8-19 months, age group 2), due to high mortality rates in these age groups. However, two perennial animals were also available for examination during this period, one of which was in good nutritional condition. Many of the seals that had been mercy-killed and found dead were in poor nutritional status. Histopathological, microbiological, parasitological and virological examinations were conducted on 69 individuals (86% (69/80)) in a suitable state of preservation. Respiratory tract parasitosis, cachexia, and bronchopneumonia were the most common causes of death or disease. Overall, there was no evidence of a relapse of a viral disease outbreak. Macrowaste, such as plastic waste or fishery-related debris, were not found in any gastrointestinal tract of the animals examined. There was also no evidence of grey seal predation. Weakness and cachexia were prominent causes of disease and death in harbour seals found within a few weeks after birth, but bronchopneumonia and septicaemia also developed in slightly older animals. Frequently found microbial pathogens in seals from Lower Saxony were similar to those found in other studies on seals from the Wadden Sea region in Schleswig-Holstein, for example streptococci and Escherichia coli/v. haemolytica, Brucella spp. and Erysipelothrix rhusiopathiae, potentially human pathogenic germs. The results of the examinations of dead harbour seals from Lower Saxony show that pathological investigations on a representative number of animals deliver urgently needed information on the health status of the population. The results represent an important contribution to the state of the top predators of the Wadden Sea as part of the obligations within the Trilateral Wadden Sea Agreement, Oslo and Paris Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) and the Marine Framework Directive. The investigations should be continued as a matter of urgency and the stranding network should be expanded.

Combination of in silico and molecular techniques for discrimination and virulence characterization of marine Brucella ceti and Brucella pinnipedialis

Introduction

Mammals are the main hosts for Brucella sp., agents of worldwide zoonosis. Marine cetaceans and pinnipeds can be infected by Brucella ceti and B. pinnipedialis, respectively. Besides classical bacteriological typing, molecular approaches such as MLVA, MLSA, and whole-genome sequencing (WGS) can differentiate these species but are cumbersome to perform.

Methods

We compared the DNA and genome sequences of 12 strains isolated from nine marine mammals, with highly zoonotic B. melitensis, B. abortus, and B. suis, and the publicly available genomes of B. ceti and B. pinnipedialis. In silico pipelines were used to detect the antimicrobial resistance (AMR), plasmid, and virulence genes (VGs) by screening six open-source and one home-made library.

Results and discussion

Our results show that easier-to-use HRM-PCR, Bruce-ladder, and Suis-ladder can separate marine Brucella sp., and the results are fully concordant with other molecular methods, such as WGS. However, the restriction fragment length polymorphism (RFLP) method cannot discriminate between B. pinnipedialis and B. ceti B1-94-like isolates. MLVA-16 results divided the investigated strains into three clades according to their preferred host, which was confirmed in WGS. In silico analysis did not find any AMR and plasmid genes, suggesting antimicrobial susceptibility of marine Brucella, while the presence of the VGs btpA gene was variable dependent on the clade.

Conclusion

The HRM-PCR and Suis-ladder are quick, easy, and cost-effective methods to identify marine Brucella sp. Moreover, in silico genome analyses can give useful insights into the genetic virulence and pathogenicity potential of marine Brucella strains.

Case Report: Neurobrucellosis Presenting as Malignancy

Neurobrucellosis, caused by Brucella species, is a zoonotic infection that may involve the central nervous system. Although uncommon, it can manifest as a solitary intracranial mass. We report a case of neurobrucellosis in a 25-year-old woman from Peru who presented with headache, weight loss, and right-side hemiparesis and paresthesia. A contrast-enhanced magnetic resonance imaging scan revealed an intracerebral mass in the left temporal lobe. Serum testing subsequently were positive. Brain biopsy demonstrated non-necrotizing granulomas without malignant cells. Neurobrucellosis should be considered in the differential diagnosis of brain space occupying lesions in endemic countries.

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.

[Zoonotic potential of brucellosis in marine mammals]

Introduction

Brucellosis in marine mammals (cetacean and pinnipeds) has emerged in a very significant way during the last two decades. Currently Brucella ceti and Brucella pinnipedialis are the two recognized species in marine mammals, but available information is still limited. Several genotypes have been identified, and studies on the relationship between sequence type (ST) and organ pathogenicity or tropism have indicated differences in pathogenesis between B. ceti sequences in cetaceans. The zoonotic potential of this disease is based on the identification of the main sources of introduction and spread of Brucella spp. in the marine environment as well as on the factors of exposure of marine mammals and humans to the bacteria.

Bibliographic review

This article is a bibliographical review on marine mammal brucellosis, including the features, sources and transmission modes of each Brucella species, as well as their potential pathogenicity in animals and humans.

Conclusion

Different genotypes of marine Brucella spp have been isolated from marine mammal species but without any evidence of pathology induced by these bacteria. Associated lesions are variable and include subcutaneous abscesses, meningo-encephalomyelitis, pneumonia, myocarditis, osteoarthritis, orchitis, endometritis, placentitis and abortion. The isolation of marine B. spp from marine mammal respiratory parasites associated to lung injury has raised the intriguing possibility that they may serve as a vector for the transmission of this bacterium.The severity of marine B. spp remains unknown due to the lack of an estimate of the prevalence of this disease in marine mammals. The number of suspected human cases is still very limited. However, by analogy with other germs of the genus Brucella responsible for abortion in ruminants and for a febrile and painful state in human beings, prevention measures are essential. The significant increase in the number of strandings coupled with a high seroprevalence in certain species of marine mammals must be considered for people in direct or indirect contact with these animals. Ongoing epidemiological monitoring combined with extensive post-mortem examinations (necropsy, bacteriology and sequencing) of all species of stranded marine mammals would deepen knowledge on the zoonotic potential of marine Brucella species.

Halocercus lagenorhynchi infection in a stranded striped dolphin Stenella coeruleoalba (Meyen, 1833) on the Southwest coastline of India

Necropsy on a striped dolphin Stenella coeruleoalba (Meyen, 1833) entangled in ghost fishing net and dead while rescuing yielded some helminth parasites, later identified as Halocercus lagenorhynchi. DNA barcoding of the host and parasite and the phylogenetic analysis of the parasite was conducted. This study provides valuable information towards establishing basal data of marine mammal parasite diversity and distribution in the Indian waters. We believe this is the first report of the occurrence of Halocercus lagenorhynchi in marine mammals in India.

Brucella infection in rough-toothed dolphin (Steno bredanensis) with severe orchitis stranded on the Pacific coast of Japan

In the western North Pacific, prominent granulomatous testes have been detected in many Brucella-infected common minke whales (Balaenoptera acutorostrata), but there have been no reports in toothed cetaceans. We found severe orchitis with granulomatous lesions in a rough-toothed dolphin (Steno bredanensis) stranded on the Pacific coast of Japan in 2011. Histopathological examination revealed leukocyte infiltration of the lesions. DNA from the lesion was analyzed by PCR and it showed molecular biological similarities with those of Brucella-infected common minke whales and Brucella ceti of sequence-type 27 (ST27). These results suggest that the type of Brucella ceti that infected the dolphin was ST27, which may have caused severe orchitis. This study adds to our understanding of Brucella infections in marine mammals.

Brucella spp. are facultative anaerobic bacteria under denitrifying conditions

IMPORTANCE

Respiration is a fundamental and complex process that bacteria use to produce energy. Despite aerobic respiration being the most common, some bacteria make use of a mode of respiration in the absence of oxygen, called anaerobic respiration, which can yield advantages in adaptation to various environmental conditions. Denitrification is part of this respiratory process ensuring higher respiratory flexibility under oxygen depletion. Here, we report for the first time the evidence of anaerobic growth of Brucella spp. under denitrifying conditions, which implies that this genus should be reconsidered as facultative anaerobic. Our study further describes that efficient denitrification is not equally found within the Brucella genus, with atypical species showing a greater ability to denitrify, correlated with higher expression of the genes involved, as compared to classical species.

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.

Brucella ceti Infection in Striped Dolphins from Italian Seas: Associated Lesions and Epidemiological Data

Brucella ceti infections have been increasingly reported in cetaceans. In this study, we analyzed all cases of B. ceti infection detected in striped dolphins stranded along the Italian coastline between 2012 and 2021 (N = 24). We focused on the pathogenic role of B. ceti through detailed pathological studies, and ad hoc microbiological, biomolecular, and serological investigations, coupled with a comparative genomic analysis of the strains. Neurobrucellosis was observed in 20 animals. The primary histopathologic features included non-suppurative meningoencephalitis (N = 9), meningitis (N = 6), and meningoencephalomyelitis (N = 5), which was also associated with typical lesions in other tissues (N = 8). Co-infections were detected in more than half of the cases, mostly involving Cetacean Morbillivirus (CeMV). The 24 B. ceti isolates were assigned primarily to sequence type 26 (ST26) (N = 21) and, in a few cases, ST49 (N = 3). The multilocus sequence typing (cgMLST) based on whole genome sequencing (WGS) data showed that strains from Italy clustered into four genetically distinct clades. Plotting these clades onto a geographic map suggests a link between their phylogeny and the topographical distribution. These results support the role of B. ceti as a primary neurotropic pathogen for striped dolphins and highlight the utility of WGS data in understanding the evolution of this emerging pathogen.

An Epidemiological Study of Brucellosis in Different Animal Species from the Al-Qassim Region, Saudi Arabia

Brucellosis is a zoonotic bacterial illness that affects humans and a variety of domestic animals, especially ruminants. It is mostly transmitted through the consumption of contaminated drinks, foods, undercooked meat, or unpasteurized milk or contact with infected animals. Therefore, the present study aimed to investigate the seroprevalence of brucellosis in camels, sheep, and goat herds in the Qassim region, Saudi Arabia, using commonly used diagnostic serological procedures such as the Rose Bengal test (RBT), complement fixation test (CFT), and enzyme-linked immunosorbent assay (ELISA). The seroprevalence of brucellosis in camels, sheep, and goats was determined in the selected areas using a cross-sectional study design and a total of 690 farm animals of both sexes of different ages from the three animal species (274 camels, 227 sheep, and 189 goats). According to RBT results, 65 sera were positive for brucellosis, including 15 (5.47%) for camels, 32 (14.09%) for sheep, and 18 (9.50%) for goats. CFT and c-ELISA were performed as confirmatory tests on positive samples resulting from RBT. With c-ELISA, 60 serum samples were confirmed positive, in 14 (5.10%), 30 (13.21%), and 16 (8.46%) camels, sheep, and goats, respectively. There were 59 serum samples confirmed as positive for CFT, including 14 (5.11%), 29 (12.77%), and 16 (8.46%) for camels, sheep, and goats, respectively. Overall, the highest seroprevalence of brucellosis was found in sheep while the least was found in camels from the three tests (RBT, c-ELISA, and CFT). The highest seroprevalence of brucellosis was found in sheep while the least seroprevalence was found in camels. There was also a higher seroprevalence of brucellosis among female animals than males as well as among old animals than young animals. The study, thus, demonstrates brucellosis seroprevalence among farm animals (camels, sheep, and goats) and the significance of intervention measures against brucellosis incidence in both humans and animals through the creation of public awareness and other relevant policy measures such as livestock vaccination, effective hygiene management, and adequate quarantine or serological analysis for newly introduced animals.

The Development of Diagnostic and Vaccine Strategies for Early Detection and Control of Human Brucellosis, Particularly in Endemic Areas

Brucellosis is considered one of the most serious zoonotic diseases worldwide. This disease affects both human and animal health, in addition to being one of the most widespread zoonotic illnesses in the Middle East and Northern Africa. Human brucellosis generally presents in a diverse and non-specific manner, making laboratory confirmation of the diagnosis critical to the patient's recovery. A coordinated strategy for diagnosing and controlling brucellosis throughout the Middle East is required, as this disease cannot be known to occur without reliable microbiological, molecular, and epidemiological evidence. Consequently, the current review focuses on the current and emerging microbiological diagnostic tools for the early detection and control of human brucellosis. Laboratory assays such as culturing, serology, and molecular analysis can frequently be used to diagnose brucellosis. Although serological markers and nucleic acid amplification techniques are extremely sensitive, and extensive experience has been gained with these techniques in the laboratory diagnosis of brucellosis, a culture is still considered to be the "gold standard" due to the importance of this aspect of public health and clinical care. In endemic regions, however, serological tests remain the primary method of diagnosis due to their low cost, user-friendliness, and strong ability to provide a negative prediction, so they are commonly used. A nucleic acid amplification assay, which is highly sensitive, specific, and safe, is capable of enabling rapid disease diagnosis. Patients who have reportedly fully healed may continue to have positive molecular test results for a long time. Therefore, cultures and serological methods will continue to be the main tools for diagnosing and following up on human brucellosis for as long as no commercial tests or studies demonstrate adequate interlaboratory reproducibility. As there is no approved vaccine that prevents human brucellosis, vaccination-based control of animal brucellosis has become an important part of the management of human brucellosis. Over the past few decades, several studies have been conducted to develop Brucella vaccines, but the problem of controlling brucellosis in both humans and animals remains challenging. Therefore, this review also aims to present an updated overview of the different types of brucellosis vaccines that are currently available.

Pathogen Exposure in White Whales (Delphinapterus leucas) in Svalbard, Norway

The Svalbard white whale (Delphinapterus leucas) population is one of the smallest in the world, making it particularly vulnerable to challenges such as climate change and pathogens. In this study, serum samples from live captured (2001−2016) white whales from this region were investigated for influenza A virus (IAV) antibodies (Abs) (n = 27) and RNA (n = 25); morbillivirus (MV) Abs (n = 3) and RNA (n = 25); Brucella spp. Abs; and Toxoplasma gondii Abs (n = 27). IAV Abs were found in a single adult male that was captured in Van Mijenfjorden in 2001, although no IAV RNA was detected. Brucella spp. Abs were found in 59% of the sample group (16/27). All MV and T. gondii results were negative. The results show that Svalbard white whales have been exposed to IAV and Brucella spp., although evidence of disease is lacking. However, dramatic changes in climate and marine ecosystems are taking place in the Arctic, so surveillance of health parameters, including pathogens, is critical for tracking changes in the status of this vulnerable population.

Brucella ceti and Brucella pinnipedialis genome characterization unveils genetic features that highlight their zoonotic potential

The Gram-negative bacteria Brucella ceti and Brucella pinnipedialis circulate in marine environments primarily infecting marine mammals, where they cause an often-fatal disease named brucellosis. The increase of brucellosis among several species of cetaceans and pinnipeds, together with the report of sporadic human infections, raises concerns about the zoonotic potential of these pathogens on a large scale and may pose a threat to coastal communities worldwide. Therefore, the characterization of the B. ceti and B. pinnipedialis genetic features is a priority to better understand the pathological factors that may impact global health. Moreover, an in-depth functional analysis of the B. ceti and B. pinnipedialis genome in the context of virulence and pathogenesis was not undertaken so far. Within this picture, here we present the comparative whole-genome characterization of all B. ceti and B. pinnipedialis genomes available in public resources, uncovering a collection of genetic tools possessed by these aquatic bacterial species compared to their zoonotic terrestrial relatives. We show that B. ceti and B. pinnipedialis genomes display a wide host-range infection capability and a polyphyletic phylogeny within the genus, showing a genomic structure that fits the canonical definition of closeness. Functional genome annotation led to identifying genes related to several pathways involved in mechanisms of infection, others conferring pan-susceptibility to antimicrobials and a set of virulence genes that highlight the similarity of B. ceti and B. pinnipedialis genotypes to those of Brucella spp. displaying human-infecting phenotypes.

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.

Survey for Leptospira and Brucella in Amazonian manatees, Amazon river dolphins, and a tucuxi in the Brazilian Amazon

Leptospirosis and brucellosis are zoonotic diseases with global distributions that represent severe hazards to humans and animals. We investigated exposure to Leptospira spp. and Brucella spp. in samples from Amazonian manatees Trichechus inunguis, Amazon river dolphins Inia geoffrensis, and a tucuxi Sotalia fluviatilis. The animals were free-ranging or undergoing in situ rehabilitation in the mid-Solimões River region, Brazilian Amazon. Serum samples from 19 Amazonian manatees were tested by microscopic agglutination test, Rose Bengal test, and 2-mercaptoethanol Brucella agglutination test. Antibodies against Leptospira spp. were detected in 63% of the manatees tested and serovar Patoc was considered the infecting serovar in all positive samples. Titers were generally low, indicating chronic exposure, but higher titers indicative of an active infection were detected in 3 animals. Anti-Brucella spp. antibodies were not detected. Tissue and/or body fluid samples from 12 Amazon river dolphins, a tucuxi, and 2 Amazonian manatees were investigated by multiplex PCR and bacteriology for Leptospira spp. and Brucella spp. All samples were negative. However, Enterococcus faecalis was isolated from uterine fluid, lymph node, and lung of 3 Amazon river dolphins. Bacillus spp. were isolated from milk and synovial fluid from 2 Amazon river dolphins and from a milk sample from 1 Amazonian manatee. Knowledge of the pathogens present in Amazonian manatees, Amazon river dolphins, and tucuxis is of great relevance to species conservation and environmental health. Although no clinical signs were noted, further research is needed to elucidate the clinical relevance of infection by Leptospira sp. serovar Patoc in Amazonian aquatic mammals.

Immunosuppressive Mechanisms in Brucellosis in Light of Chronic Bacterial Diseases

Brucellosis is considered one of the major zoonoses worldwide, constituting a critical livestock and human health concern with a huge socio-economic burden. Brucella genus, its etiologic agent, is composed of intracellular bacteria that have evolved a prodigious ability to elude and shape host immunity to establish chronic infection. Brucella's intracellular lifestyle and pathogen-associated molecular patterns, such as its specific lipopolysaccharide (LPS), are key factors for hiding and hampering recognition by the immune system. Here, we will review the current knowledge of evading and immunosuppressive mechanisms elicited by Brucella species to persist stealthily in their hosts, such as those triggered by their LPS and cyclic β-1,2-d-glucan or involved in neutrophil and monocyte avoidance, antigen presentation impairment, the modulation of T cell responses and immunometabolism. Attractive strategies exploited by other successful chronic pathogenic bacteria, including Mycobacteria, Salmonella, and Chlamydia, will be also discussed, with a special emphasis on the mechanisms operating in brucellosis, such as granuloma formation, pyroptosis, and manipulation of type I and III IFNs, B cells, innate lymphoid cells, and host lipids. A better understanding of these stratagems is essential to fighting bacterial chronic infections and designing innovative treatments and vaccines.

Identification of cerebrospinal fluid metabolites as biomarkers for neurobrucellosis by liquid chromatography-mass spectrometry approach

Neurobrucellosis is the most morbid form in brucellosis disease. Metabolomics is an emerging method which intends to explore the global alterations of various metabolites in samples. We aimed to identify metabolites in cerebrospinal fluid (CSF) as biomarkers that were potentially unique for neurobrucellosis. CSF samples from 25 neurobrucellosis patients and 25 normal controls (uninfected patients with hydrocephalus) were collected for metabolite detection using liquid chromatography-mass spectrometry (LC-MS) approach. Inflammatory cytokines in CSF were measured with Enzyme-linked immunosorbent assay (ELISA). The base peak chromatogram in CSF samples showed that small-molecule metabolites were well separated. Principal Component Analysis (PCA) analysis exhibited the examined samples were arranged in two main clusters in accordance with their group. Projection to Latent Structures Discriminant Analysis (PLS-DA) revealed there was a noticeable separation between neurobrucellosis and normal groups. Orthogonal Partial Least-Squares-Discriminant Analysis (OPLS-DA) could responsibly illuminate the differences between neurobrucellosis and normal controls. Neurobrucellosis showed a total of 155 differentiated metabolites. Prominent potential biomarkers including 30 metabolites were then selected out, regarded as more capable of distinguishing neurobrucellosis. TNF-α and IL-6 in CSF were remarkably increased in neurobrucellosis. We presented the heatmaps and correlation analyses among the identified 30 potential biomarkers. In conclusion, this study showed that CSF metabolomics based on LC-MS could distinguish neurobrucellosis patients from normal controls. Our data offered perspectives for diagnosis and treatment for neurobrucellosis.

Brucella ceti sequence type 23, 26, and 27 infections in North American cetaceans

Brucella ceti infection is associated with a variety of disease outcomes in cetaceans globally. Multiple genotypes of B. ceti have been identified. This retrospective aimed to determine if specific lesions were associated with different B. ceti DNA sequence types (STs). Characterization of ST was performed on 163 samples from 88 free-ranging cetaceans, including common bottlenose dolphin Tursiops truncatus (T.t.; n = 73), common short-beaked dolphin Delphinus delphis (D.d.; n = 7), striped dolphin Stenella coeruleoalba (n = 3), Pacific white-sided dolphin Lagenorhynchus obliquidens (n = 2), sperm whale Physeter macrocephalus (n = 2), and harbour porpoise Phocoena phocoena (n = 1), that stranded along the coast of the US mainland and Hawaii. ST was determined using a previously described insertion sequence 711 quantitative PCR. Concordance with 9-locus multi-locus sequence typing was assessed in a subset of samples (n = 18). ST 26 was most commonly identified in adult dolphins along the US east coast with non-suppurative meningoencephalitis (p = 0.009). Animals infected with ST 27 were predominately perinates that were aborted or died shortly after birth with evidence of in utero pneumonia (p = 0.035). Reproductive tract inflammation and meningoencephalitis were also observed in adult T.t. and D.d. with ST 27, though low sample size limited interpretation. ST 23 infections can cause disease in cetacean families other than porpoises (Phocoenidae), including neurobrucellosis in D.d. In total, 11 animals were potentially infected with multiple STs. These data indicate differences in pathogenesis among B. ceti STs in free-ranging cetaceans, and infection with multiple STs is possible.

Brucella and Its Hidden Flagellar System

Brucella, a Gram-negative bacterium with a high infective capacity and a wide spectrum of hosts in the animal world, is found in terrestrial and marine mammals, as well as amphibians. This broad spectrum of hosts is closely related to the non-classical virulence factors that allow this pathogen to establish its replicative niche, colonizing epithelial and immune system cells, evading the host's defenses and defensive response. While motility is the primary role of the flagellum in most bacteria, in Brucella, the flagellum is involved in virulence, infectivity, cell growth, and biofilm formation, all of which are very important facts in a bacterium that to date has been described as a non-motile organism. Evidence of the expression of these flagellar proteins that are present in Brucella makes it possible to hypothesize certain evolutionary aspects as to where a free-living bacterium eventually acquired genetic material from environmental microorganisms, including flagellar genes, conferring on it the ability to reach other hosts (mammals), and, under selective pressure from the environment, can express these genes, helping it to evade the immune response. This review summarizes relevant aspects of the presence of flagellar proteins and puts into context their relevance in certain functions associated with the infective process. The study of these flagellar genes gives the genus Brucella a very high infectious versatility, placing it among the main organisms in urgent need of study, as it is linked to human health by direct contact with farm animals and by eventual transmission to the general population, where flagellar genes and proteins are of great relevance.

Cross-sectional study of Brucella spp. using real-time PCR from bovine whole blood in Colombia

A cross-sectional study was conducted in Colombia to recover Brucella spp. DNA from bovine whole-blood samples through probe-based real-time PCR (qPCR). By an SNP-based assay, vaccine strains were differentiated from field strains. The associated factors were evaluated using logistical regression models. A total of 656 random cows from 40 herds were selected and analyzed using serology and PCR. The qPCR assay detected 9.5% (n = 62/656; 95% CI: 7.3, 12.0) of the animals with Brucella-DNA presence, while the serological test detected a 6.6% (n = 43/656; CI: 4.8, 8.7). 62.5% (n = 25/40; 95% CI: 45.8, 77.3) of positive cases were detected at the herd-level by the qPCR, while only 27.5% (n = 11/40; 95% CI: 14.6, 43.9) were detected by the serological test. All positive samples were identified as field Brucella strains employing the SNP-based assay. In the final regression model at the animal-level, five variables were associated with Brucella-DNA presence: the use of bulls for mating recorded history of reproductive problems, pregnant cows, parlor milking, and cows belonging to farms ≤200 m from the main road. At the herd-level, two variables were associated with Brucella-DNA presence: recorded history of reproductive problems and the use of bulls for mating. Given the fluctuant brucellosis prevalence in endemic areas, updated epidemiological studies are necessary to evaluate the disease dynamic and if established prevention and control measures have been effective or need to be adjusted. The increase in the prevalence of brucellosis in animal reservoirs creates an important risk of transmission in humans.

PdeA is required for the rod shape morphology of Brucella abortus

Cyclic-di-GMP plays crucial role in the cell cycle regulation of the α-Proteobacterium Caulobacter crescentus. Here we investigated its role in the α-Proteobacterium Brucella abortus, a zoonotic intracellular pathogen. Surprisingly, deletion of all predicted cyclic-di-GMP synthesizing or degrading enzymes did not drastically impair the growth of B. abortus, nor its ability to grow inside cell lines. As other Rhizobiales, B. abortus displays unipolar growth from the new cell pole generated by cell division. We found that the phosphodiesterase PdeA, the ortholog of the essential polar growth factor RgsP of the Rhizobiale Sinorhizobium meliloti, is required for rod shape integrity but is not essential for B. abortus growth. Indeed, the radius of the pole is increased by 31 ± 1.7% in a ΔpdeA mutant, generating a coccoid morphology. A mutation in the cyclic-di-GMP phosphodiesterase catalytic site of PdeA does not generate the coccoid morphology and the ΔpdeA mutant kept the ability to recruit markers of new and old poles. However, the presence of PdeA is required in an intra-nasal mouse model of infection. In conclusion, we propose that PdeA contributes to bacterial morphology and virulence in B. abortus, but it is not crucial for polarity and asymmetric growth.

Case Report: Metagenomic Next-Generation Sequencing Confirmed a Case of Central Nervous System Infection With Brucella melitensis in Non-endemic Areas

Brucellosis is a highly contagious zoonotic disease caused by bacteria that belong to the genus Brucella. It is a major endemic disease in northern China. We reported a rare case of central nervous system (CNS) infection caused by Brucella melitensis in a patient living in non-endemic areas. The medical history of the patient included chronic headache and trunk numbness. Based on the presented clinical symptoms and medical examinations, a clinical diagnosis of binocular uveo-encephalitis was made in the local hospital. The patient's symptoms were unrelieved after being treated with empiric therapy. Soon after, the patient was admitted to our hospital because of the obnubilation and coma in the trip. We ran a few examinations and sent the cerebrospinal fluid (CSF) for metagenomic next-generation sequencing (mNGS) immediately. The Magnetic resonance imaging (MRI) examination was unremarkable, and bilateral mastoid inflammation was attached. Metagenomic next-generation sequencing suggested a CNS infection caused by Brucella melitensis. Then, the results of the serum agglutination test and quantitative polymerase chain reaction assay also confirmed that. After being treated with doxycycline, rifampin, and cefatriaxone, consciousness of the patient was restored and headache diminished. Two months later, a lumbar puncture was used to check the pressure of the CSF, and the total course of treatment was more than 6 months. This case highlighted the potential value of mNGS in early clinal diagnosis. We believe that mNGS may be a complementary method for rapid identification of infection of CNS caused by the pathogen.

Brucella Infection Investigation in Cetaceans and Manatees in Northeast Brazil

Among the bacterial infections that impair the health status of marine mammals, those caused by Brucella spp. are the most reported worldwide. Brucella infections in marine mammals can result in acute or chronic disease and are associated with variable clinical outcomes, depending on the organ involved during the infectious process, infection route, host immunity, and strain pathogenicity. Asymptomatic infections may also occur. The current study expands the investigation of Brucella infection in northeast Brazil by analyzing 19 dead, stranded cetaceans and 52 Antillean manatees Trichechus manatus manatus. The manatees included 8 dead, captive manatees and 44 live specimens, of which 10 were analyzed only after reintroduction into the wild as part of a rehabilitation program, 9 were analyzed both while in captivity or semi-captivity and after reintroduction, 20 were sampled only in captivity or semi-captivity, and 5 were free-living manatees. Serological tests were used to screen for antibodies against smooth Brucella spp. Whole blood, swabs, and tissue samples were screened for Brucella spp. DNA by PCR. Samples with positive PCR results were cultured for Brucella spp. isolation. All manatees yielded negative results in serological and molecular tests. Brucella spp. DNA was detected in the kidney of one adult Guiana dolphin Sotalia guianensis exhibiting necrosis in the liver. No growth of Brucella spp. was observed via microbiological culturing. This study is the first report of Brucella spp. DNA detection in cetaceans in the state of Pernambuco, and it highlights the importance of conducting systematic monitoring for the presence of Brucella infection in marine mammals along the Brazilian coast, especially in the northeast region, where several cases have been reported.

The one hundred year journey of the genus Brucella (Meyer and Shaw 1920)

The genus Brucella, described by Meyer and Shaw in 1920, comprises bacterial pathogens of veterinary and public health relevance. For 36 years, the genus came to include three species that caused brucellosis in livestock and humans. In the second half of the 20th century, bacteriologists discovered five new species and several 'atypical' strains in domestic animals and wildlife. In 1990, the Brucella species were recognized as part of the Class Alphaproteobacteria, clustering with pathogens and endosymbionts of animals and plants such as Bartonella, Agrobacterium and Ochrobactrum; all bacteria that live in close association with eukaryotic cells. Comparisons with Alphaproteobacteria contributed to identify virulence factors and to establish evolutionary relationships. Brucella members have two circular chromosomes, are devoid of plasmids, and display close genetic relatedness. A proposal, asserting that all brucellae belong to a single species with several subspecies debated for over 70 years, was ultimately rejected in 2006 by the subcommittee of taxonomy, based on scientific, practical, and biosafety considerations. Following this, the nomenclature of having multiples Brucella species prevailed and defined according to their molecular characteristics, host preference, and virulence. The 100-year history of the genus corresponds to the chronicle of scientific efforts and the struggle for understanding brucellosis.

Brucella sp. sequence-type 27 associated with abortion in dwarf sperm whale Kogia sima

A dwarf sperm whale Kogia sima stranded alive along the Central Pacific Coast of Costa Rica. The whale, handled by tourists and local inhabitants, was weak, had buoyancy difficulties, and eventually aborted and died, showing severe necrotizing placentitis and other pathological signs. Both the mother and the fetus had antibodies against Brucella lipopolysaccharide. Brucella organisms were isolated from various tissues of both animals and were characterized. The bacterium genome corresponded to sequence-type 27 (ST27) and clustered together with other Brucella ST27 isolated in humans and cetaceans.

Bovine brucellosis - a comprehensive review

Brucellosis is a zoonotic disease of great animal welfare and economic implications worldwide known since ancient times. The emergence of brucellosis in new areas as well as transmission of brucellosis from wild and domestic animals is of great significance in terms of new epidemiological dimensions. Brucellosis poses a major public health threat by the consumption of non-pasteurized milk and milk products produced by unhygienic dairy farms in endemic areas. Regular and meticulous surveillance is essentially required to determine the true picture of brucellosis especially in areas with continuous high prevalence. Additionally, international migration of humans, animals and trade of animal products has created a challenge for disease spread and diagnosis in non-endemic areas. Isolation and identification remain the gold standard test, which requires expertise. The advancement in diagnostic strategies coupled with screening of newly introduced animals is warranted to control the disease. Of note, the diagnostic value of miRNAs for appropriate detection of B. abortus infection has been shown. The most widely used vaccine strains to protect against Brucella infection and related abortions in cattle are strain 19 and RB51. Moreover, it is very important to note that no vaccine, which is highly protective, safe and effective is available either for bovines or human beings. Research results encourage the use of bacteriophage lysates in treatment of bovine brucellosis. One Health approach can aid in control of this disease, both in animals and man.

Uncovering the Hidden Credentials of Brucella Virulence

Bacteria in the genus Brucella are important human and veterinary pathogens. The abortion and infertility they cause in food animals produce economic hardships in areas where the disease has not been controlled, and human brucellosis is one of the world's most common zoonoses. Brucella strains have also been isolated from wildlife, but we know much less about the pathobiology and epidemiology of these infections than we do about brucellosis in domestic animals. The brucellae maintain predominantly an intracellular lifestyle in their mammalian hosts, and their ability to subvert the host immune response and survive and replicate in macrophages and placental trophoblasts underlies their success as pathogens. We are just beginning to understand how these bacteria evolved from a progenitor alphaproteobacterium with an environmental niche and diverged to become highly host-adapted and host-specific pathogens. Two important virulence determinants played critical roles in this evolution: (i) a type IV secretion system that secretes effector molecules into the host cell cytoplasm that direct the intracellular trafficking of the brucellae and modulate host immune responses and (ii) a lipopolysaccharide moiety which poorly stimulates host inflammatory responses. This review highlights what we presently know about how these and other virulence determinants contribute to Brucella pathogenesis. Gaining a better understanding of how the brucellae produce disease will provide us with information that can be used to design better strategies for preventing brucellosis in animals and for preventing and treating this disease in humans.

Evaluation of clinical, diagnostic features and therapeutic outcome of neurobrucellosis: a case series and review of literature

AIM

In this study, we aimed to discuss the clinical features, laboratory findings, treatment and outcome of seven cases of neurobrucellosis from a tertiary care center and review the available global literature.

MATERIALS AND METHODS

The diagnosis of neurobrucellosis was established using the following criteria in our setting: (1) signs and symptoms of neurological infection with examination of cerebrospinal fluid (CSF) revealing signs of meningitis, (2) isolation of Brucella spp. from blood and/or CSF and/or antibody titer ≥1:160 in serum using standard agglutination test (SAT) and/or the presence of anti-Brucella antibodies in CSF and/or detection of Brucella spp.-specific DNA from CSF using PCR. A literature search was performed to review previous cases of neurobrucellosis published worldwide during the last 30 years.

RESULTS

The proportion of neurobrucellosis was 2.8% in our setting. Fever with headache and altered sensorium were the major presenting complaints. Brucella melitensis was isolated from blood culture in 6 patients. From the literature search, a total of 221 cases of neurobrucellosis were reviewed and analyzed. Meningitis (32.6%), loss of hearing (25.8%) and encephalitis (14.9%) were the most common clinical features. Involvement of cranial nerves, polyradiculopathy and paraplegia were the major complications found in patients with neurobrucellosis.

CONCLUSIONS

Neurobrucellosis should always be considered in the differential diagnosis of befitting neurological, rheumatological, and neuropsychiatric presentations in endemic regions for brucellosis. To prevent morbidity and mortality associated with neurobrucellosis, a multimodal diagnostic approach is essential for early and accurate diagnosis and effective treatment.

Occurrence of Brucella ceti in stranded bottlenose dolphins Tursiops truncatus coincides with calving season

Brucellosis is a disease caused by the Gram-negative facultative intracellular bacterium Brucella spp. In terrestrial species, this zoonotic bacterium is a global public health risk, but there is also concern over the zoonotic potential of marine forms, such as B. ceti, which affects cetaceans. Due to the detection of B. ceti in samples from bottlenose dolphins Tursiops truncatus during the 2010-2014 Gulf of Mexico Unusual Mortality Event, a long-term study of the prevalence of Brucella in stranded bottlenose dolphins from South Carolina, USA, was conducted. From 2012 through 2017, 282 stranded bottlenose dolphins were tested for B. ceti via real-time PCR. Nearly 32% of the dolphins tested positive in at least one sample (brain, lung, blowhole swab). Very little information exists in the literature on the occurrence of Brucella spp. in marine mammals, though in terrestrial species, such as cattle and elk, higher prevalence is often reported in spring. Similar results were found in this study with the peak occurrence being between March and June, a known period of calving in South Carolina. Results from this study provide important insights into the occurrence of the marine bacterium B. ceti.

Occurrence of Brucella ceti in striped dolphins from Italian Seas

Brucella ceti infections have been increasingly reported in cetaceans, although a very limited characterization of Mediterranean Brucella spp. isolates has been previously reported and relatively few data exist about brucellosis among cetaceans in Italy. To address this gap, we studied 8 cases of B. ceti infection in striped dolphins (Stenella coeruleoalba) stranded along the Italian coastline from 2012 to 2018, investigated thanks to the Italian surveillance activity on stranded cetaceans. We focused on cases of stranding in eastern and western Italian seas, occurred along the Apulia (N = 6), Liguria (N = 1) and Calabria (N = 1) coastlines, through the analysis of gross and microscopic findings, the results of microbiological, biomolecular and serological investigations, as well as the detection of other relevant pathogens. The comparative genomic analysis used whole genome sequences of B. ceti from Italy paired with the publicly available complete genomes. Pathological changes consistent with B. ceti infection were detected in the central nervous system of 7 animals, showing non-suppurative meningoencephalitis. In 4 cases severe coinfections were detected, mostly involving Dolphin Morbillivirus (DMV). The severity of B. ceti-associated lesions supports the role of this microbial agent as a primary neurotropic pathogen for striped dolphins. We classified the 8 isolates into the common sequence type 26 (ST-26). Whole genome SNP analysis showed that the strains from Italy clustered into two genetically distinct clades. The first clade comprised exclusively the isolates from Ionian and Adriatic Seas, while the second one included the strain from the Ligurian Sea and those from the Catalonian coast. Plotting these clades onto the geographic map suggests a link between their phylogeny and topographical distribution. These results represent the first extensive characterization of B. ceti isolated from Italian waters reported to date and show the usefulness of WGS for understanding of the evolution of this emerging pathogen.

Temporal and spatial distribution trends of human brucellosis in Liaoning Province, China

Brucellosis is a natural epidemic zoonotic disease. Liaoning province, north-east of China, has been among the top 10 provinces with highest brucellosis incidence. In this study, the spatial and temporal distribution of brucellosis in Liaoning Province from 2006 through 2017 was analysed using the Bayesian theory of space-time modelling. The study found that in Liaoning Province, (a) all regions of the entire study area were stable counties; (b) the risk of brucellosis declined slowly with time without an obvious trend; (c) the declining trend of disease risk in three sub-hot-spot counties was faster than the overall trend, whereas in other counties, the trend was similar to the overall trend. Furthermore, the time and spatial trends of brucellosis incidence in Liaoning Province were calculated and analysed. These results may provide a theoretical and scientific basis for the public health department to develop targeted effective prevention and control measures for the disease.

Molecular characterization of Brucella ceti from a bottlenose dolphin (Tursiops truncatus) with osteomyelitis in the western Pacific

Although the presence of Brucella spp. in the western Pacific has been suggested by epidemiological studies on cetaceans, it has not been confirmed by bacterial isolation. Here, for the first time, we report that a marine Brucella strain was isolated in the western Pacific from a bottlenose dolphin with osteomyelitis. The isolate from the lesion was confirmed to be B. ceti of sequence type 27 by multilocus sequence typing and Bruce-ladder PCR. Infrequent-restriction-site PCR and omp2 gene sequencing revealed that molecular characteristics of this isolate were similar to those of Brucella DNA previously detected from minke whales in the western North Pacific. These results suggest that genetically related Brucella strains circulate in cetacean species in this region.

Detection of Brucella ceti in Two Indo-Pacific Finless Porpoises (Neophocaena Phocaenoides) Stranded in Hong Kong

Brucella ceti has been detected in several species of free-ranging odontocetes, in several geographic areas but it has not been reported in Indo-Pacific finless porpoises (Neophocaena phocaenoides) nor in any odontocetes in waters in the South China Sea. Sampling of odontocetes stranded in Hong Kong Special Administrative Region, People's Republic of China, was carried out as part of a stranding monitoring program to evaluate the pathogens harbored by these threatened species. A real-time PCR method targeting the Brucella genus-specific 31kDa Brucella cell surface salt extractable (bcsp31) gene, gene sequencing, and phylogenetic characterisation produced three PCR products of the expected size and sequence, from two stranded Indo-Pacific finless porpoises. The PCR products were obtained from brain tissue from of a neonate and from mammary fluid from a sexually mature female. Further testing for this pathogen should be performed to determine whether Brucella ceti might have a detrimental effect on reproduction and calf survival in Indo-Pacific finless porpoises and pose a threat to the conservation of this species. The importance of biosafety and biosecurity measures when handling cetaceans or their tissues and products in the South China Sea is also highlighted.

Perceptions and preparedness of veterinarians to combat brucellosis through Brucellosis Control Programme in India

Background and Aim:

Brucellosis caused by bacteria belongs to the genus Brucella is an important zoonosis and constitutes a serious public health hazard worldwide including India. The present study aimed to estimate the knowledge of veterinarians on brucellosis, its public health threat, diagnosis, and vaccination.

Materials and Methods:

This cross-sectional study was conducted during 2013-2015 and 453 veterinarians representing 11 states/Union Territories (UT) of India (Assam, Tripura, Meghalaya, Goa, Karnataka, Madhya Pradesh, Uttar Pradesh, Delhi, Jammu and Kashmir, Tamil Nadu, and Punjab) were interviewed using self-administered questionnaire.

Results:

Out of 453 veterinarians, 71.74% stated handling of the animals on day-to-day basis and 28.25% were engaged in administration activities. The veterinarians ranked foot-and-mouth disease and brucellosis at the first and fourth ranks among the list of ten economic impacted diseases in the country. A significant association was observed between laboratory confirmation with those who handled brucellosis-suspected cases (p=0.000). Similarly, significant association was noted for the availability of vials/slides (p=0.114), vacutainers (p=0.008), icebox (p=0.103), and refrigerator (p=0.106) for those who preferred laboratory diagnosis. Only 20% of the veterinarians recommended vaccination against bovine brucellosis, and 17% obtained laboratory confirmation for the brucellosis-suspected cases.

Conclusion:

The study highlighted the need for awareness programs, laboratory facilities, veterinary doctors, and protective measures for the veterinarians for combating brucellosis through the control program in the country.

Taxonomic Organization of the Family Brucellaceae Based on a Phylogenomic Approach

Deciphering the evolutionary history of pathogenic bacteria and their near neighbors may help to understand the genetic or ecological bases which led to their pathogenic behavior. The Brucellaceae family comprises zoonotic pathogenic species belonging to the genus Brucella as well as the environmental genus Ochrobactrum for which some species are considered as opportunistic pathogens. Here, we used a phylogenomic approach including a set of 145 Brucellaceae genomes representative of the family diversity and more than 40 genomes of the order Rhizobiales to infer the taxonomic relationships between the family’s species. Our results clarified some unresolved phylogenetic ambiguities, conducting to the exclusion of Mycoplana spp. out of the family Brucellaceae and the positioning of all Brucella spp. as a single genomic species within the current Ochrobactrum species diversity. Additional analyses also revealed that Ochrobactrum spp. separate into two clades, one comprising mostly environmental species while the other one includes the species considered as pathogens (Brucella spp.) or opportunistic pathogens (mainly O. anthropi, O. intermedium, and O. pseudintermedium). Finally, we show that O. intermedium is undergoing a beginning of genome reduction suggestive of an ongoing ecological niche specialization, and that some lineages of O. intermedium and O. anthropi may shift toward an adaption to the human host.

Neurobrucellosis: A neglected entity? An update from tertiary care Neurocentre of South East Asia

Neurobrucellosis is the most serious complication of brucellosis with neither a typical clinical manifestations nor a specific cerebrospinal fluid (CSF) picture and mimics other neurological disorders leading to diagnostic dilemma. The prevalence of Neurobrucellosis ranges from 1.7 to 10% of brucellosis worldwide. This present study highlights the integrated diagnostic and clinical approaches in the diagnosis of neurobrucellosis. Cases with neurological abnormalities associated with abnormal CSF findings were included in the study. Serum and CSF samples were subjected to Rose Bengal Plate Test (RBPT), standard tube agglutination test (STAT), indirect Enzyme linked immunosorbent assay (iELISA) for IgM & IgG antibodies and polymerase chain reaction (PCR) to detect BCSP31 gene. Out of 473 cases, 278 (58.8%) were positive in serum and/or CSF by any of the methods. Out of 278, Only IgM anti-brucella antibody was positive in 105 (22.19%) cases. 122 (25.79%) cases were positive by any of the diagnostic methods in serum and not in CSF whereas 51(10.78%) cases were positive in serum and CSF and these 51 cases were considered as Neurobrucellosis among patients presenting with neurological illness. Chronic meningitis was the most common form of presentation. Multimodal differential diagnostic approaches are crucial for accurate diagnosis, effective treatment and to prevent morbidity and mortality associated with neurobrucellosis.

Prediction of Human Brucellosis in China Based on Temperature and NDVI

Brucellosis occurs periodically and causes great economic and health burdens. Brucellosis prediction plays an important role in its prevention and treatment. This paper establishes relationships between human brucellosis (HB) and land surface temperature (LST), and the normalized difference vegetation index (NDVI). A seasonal autoregressive integrated moving average with exogenous variables (SARIMAX) model is constructed to predict trends in brucellosis rates. The fitted results (Akaike Information Criterion (AIC) = 807.58, Schwarz Bayes Criterion (SBC) = 819.28) showed obvious periodicity and a rate of increase of 138.68% from January 2011 to May 2016. We found a significant effect between HB and NDVI. At the same time, the prediction part showed that the highest monthly incidence per year has a decreasing trend after 2015. This may be because of the brucellosis prevention and control measures taken by the Chinese Government. The proposed model allows the early detection of brucellosis outbreaks, allowing more effective prevention and control.

Neurobrucellosis in a common bottlenose dolphin (Tursiops truncatus) stranded in the Canary Islands

Background

Brucella spp. isolation is increasingly reported in cetaceans, although associated pathologies, including lesions of the musculoskeletal and nervous systems, are less frequently described. Concerning the nervous system, Brucella sp. infection causing meningitis, meningoencephalitis or meningoencephalomyelitis have been extensively reported in striped dolphins (Stenella coeruleoalba), and less frequently in other cetacean species.

Case presentation

A juvenile female common bottlenose dolphin (Tursiops truncatus) was found stranded alive in Lanzarote (Canary Islands, Spain) in 2005, but died shortly after. On physical examination, the dolphin showed a moderate body condition and was classified as code 2 (fresh dead) at the time of necropsy. The main gross findings were severe multiorgan parasitism, thickened and congested leptomeninges, and (sero)fibrino-suppurative and proliferative arthritis of the shoulder joint. Histopathological examination revealed the distinct features of a sub-acute systemic disease associated with Cetacean Morbillivirus (CeMV) infection. However, brain lesions diverged from those reported in systemic CeMV infection. This led to suspect that there was a coinfecting pathogen, based on the characteristics of the inflammatory response and the lesion distribution pattern in the central nervous system. Brucella sp. was detected in the brain tissue by PCR and Brucella antigen was demonstrated by immunohistochemistry in the brain and shoulder joint lesions.

Conclusions

The zoonotic potential of marine mammal strains of Brucella has been demonstrated both in natural and laboratory conditions. In this study, PCR detected Brucella sp. in the brain of a common bottlenose dolphin stranded in the Canary Islands; the dolphin was also co-infected with CeMV. This is the first detection of Brucella sp. infection in a stranded cetacean in this archipelago. Therefore, we stress the importance of taking adequate measures during the handling of these species to prevent the transmissions of the infection to humans.

CLINICOPATHOLOGIC FEATURES OF INFECTION WITH NOVEL BRUCELLA ORGANISMS IN CAPTIVE WAXY TREE FROGS ( PHYLLOMEDUSA SAUVAGII) AND COLORADO RIVER TOADS ( INCILIUS ALVARIUS)

Two novel and distinct Brucella strains were recovered from 5 of 10 adult, sex undetermined, captive waxy tree frogs ( Phyllomedusa sauvagii) and two of five adult, sex undetermined, captive Colorado river toads ( Incilius alvarius) held in a zoologic collection with clinical and pathologic findings of bacterial disease. These amphibians originated from three separate private breeding facilities over several years and exhibited disease 9-49 mo following release from quarantine. Common presenting signs were vague but included focal abscessation, weight loss, change in coloration, anorexia, and decreased perching. Two waxy tree frogs and one Colorado river toad recovered with supportive care and antimicrobial treatment based on susceptibility testing. Microgranulomatosis, subcutaneous and renal abscessation, femoral osteomyelitis, and multicentric infection were the most common histologic findings. The organisms were identified antemortem in samples from subcutaneous abscesses, cloaca, and skin and from a variety of organ systems postmortem, and demonstrated a consistent susceptibility pattern. Initial isolates were misidentified as Ochrobactrum anthropi. Polymerase chain reaction and sequencing of the 16S rRNA gene identified the two organisms as novel Brucella strains similar to Brucella inopinata-like sp. and other novel organisms within the emerging "BO clade." Brucella strain oaks (isolated from waxy tree frogs) and Brucella strain leathers (isolated from Colorado river toads) differed from each other by 16 of 571 base pairs in a region of chromosome 2, and did not closely match any previous GenBank entries. This report describes the clinicopathologic features of infection by these bacteria in two amphibian species and expands the range of novel Brucella organisms from amphibian reservoirs.

Molecular, serological, pathological, immunohistochemical and microbiological investigation of Brucella spp. in marine mammals of Brazil reveals new cetacean hosts

Brucella-exposure and infection is increasingly recognized in marine mammals worldwide. To better understand the epidemiology and health impacts of Brucella spp. in marine mammals of Brazil, molecular (conventional PCR and/or real-time PCR), serological (Rose Bengal Test [RBT], Competitive [c]ELISA, Serum Agglutination Test [SAT]), pathological, immunohistochemical (IHC) and/or microbiological investigations were conducted in samples of 129 stranded or by-caught marine mammals (orders Cetartiodactyla [n = 124], Carnivora [n = 4] and Sirenia [n = 1]). Previous serological tests performed on available sera of 27 of the 129 animals (26 cetaceans and one manatee), indicated 10 seropositive cetaceans. Conventional PCR and/or real-time PCR performed in cases with available organs (n = 119) and/or blood or swabs (n = 10) revealed 4/129 (3.1%) Brucella-infected cetaceans (one of them with positive serology; the remaining three with no available sera). Pathological, IHC and/or microbiological analyses conducted in PCR/real-time PCR and/or seropositive cases (n = 13) revealed Brucella-type lesions, including meningitis/meningoencephalitis, pneumonia, necrotizing hepatitis, pericarditis and osteoarthritis in some of those animals, and positive IHC was found in all of them (excepting two live-stranded animals without available organs). Brucella spp. culture attempts were unsuccessful. Our results demonstrated exposure, asymptomatic, acute and chronic Brucella sp. infection in several cetacean species in the Brazilian coast, highlighting the role of this pathogen in stranding and/or death, particularly in Clymene dolphin (Stenella clymene) and short-finned pilot whale (Globicephala macrorhynchus) off Ceará State. Novel hosts susceptible to Brucella included the franciscana (Pontoporia blainvillei), the Guiana dolphin (Sotalia guianensis) and the spinner dolphin (Stenella longirostris). Additionally, three coinfection cases involving Brucella spp. and cetacean morbillivirus, Edwarsiella tarda and Proteus mirabilis were detected. To the best of our knowledge, this is the first long-term and large-scale survey of Brucella spp. in marine mammals of South America, widening the spectrum of susceptible hosts and geographical distribution range of this agent with zoonotic potential.

Distribution of Brucella field strains isolated from livestock, wildlife populations, and humans in Italy from 2007 to 2015

Brucellosis is a major public health problem still prevalent as a neglected endemic zoonosis requiring proactive attention in many communities worldwide. The present study involved analysis of Brucella field strains submitted for typing to the Italian National Reference Laboratory for Brucellosis from 2007 to 2015. Strains were identified at the species and biovar levels by classic and molecular techniques according to the World Organisation for Animal Health Manual. In total, 5,784 strains were typed: 3,089 Brucella abortus (53.4%), 2,497 B. melitensis (43.2%), 10 B. ovis (0.2%), 181 B. suis (3.1%), and 7 B. ceti (0.1%). The 2,981 strains from cattle were typed as B. abortus biovars 1, 3, and 6 (90.1%) and B. melitensis biovar 3 (9.9%). The 318 strains from water buffalo were typed as B. abortus biovars 1, 3 (95.9%) and B. melitensis biovar 3 (4.1%). The 2,279 strains from sheep and goats were typed as B. abortus biovars 1 and 3 (4.3%); B. melitensis biovars 1, 3, (95.3%); and B. ovis (0.4%). The 173 strains from wild boar were typed as B. suis biovar 2 (98.3%) and B. melitensis biovar 3 (1.7%). The 11 strains from pigs were typed as B. suis biovar 2. The 13 strains from humans were typed as B. melitensis biovar 3. The two strains from horses were typed as B. abortus biovar 1, while the seven strains from dolphins were typed as B. ceti. This additional knowledge on the epidemiology of brucellosis in Italy may be useful to formulate policies and strategies for the control and eradication of the disease in animal populations. The animal species affected, biovars typed, geographical origins, and spatial distributions of isolates are herein analyzed and discussed.

Concomitant Temperature Stress and Immune Activation may Increase Mortality Despite Efficient Clearance of an Intracellular Bacterial Infection in Atlantic Cod

The environmental temperature has profound effects on biological systems of marine aquatic organisms and plays a critical role in species distribution and abundance. Particularly during the warmer seasons, variations in habitat temperature may introduce episodes of stressful temperatures which the organisms must adapt to and compensate for to maintain physiological homeostasis. The marine environment is changing and predicted raises in water temperatures will affect numerous marine species. Translocation of pathogens follow migration of species and alternations in physical environmental parameters may have influence upon the virulence of pathogens, as well as the hosts immune responses. While pathogenicity of many true pathogens is expected to increase following climate induced temperature stress, the impact from environmental stressors on the occurrence and severity of opportunistic infections is unknown. Here we describe how thermal stress in the cold-water species Atlantic cod influenced the fish immune responses against an opportunistic intracellular bacterium. Following experimental infection with Brucella pinnipedialis at normal water temperature (6°C) and sub-optimal temperature (15°C), cod cleared the intracellular bacteria more rapidly at the highest temperature. The overall immune response was faster and of higher amplitude at 15°C, however, a significant number of cod died at this temperature despite efficient clearance of infection. An increased growth rate not affected by infection was observed at 15°C, confirming multiple energy demanding processes taking place. Serum chemistry suggested that general homeostasis was influenced by both infection and increased water temperature, highlighting the cumulative stress responses (allostatic load) generated by simultaneous stressors. Our results suggest a trade-off between resistance and tolerance to survive infection at sub-optimal temperatures and raise questions concerning the impact of increased water temperatures on the energetic costs of immune system activation in aquatic ectotherms.

Brucella pinnipedialis in lungworms Parafilaroides sp. and Pacific harbor seals Phoca vitulina richardsi: proposed pathogenesis

Brucella spp. were first isolated from marine mammals in 1994 and since have been described in numerous pinniped and cetacean species with nearly global distribution. Microscopic, electron microscopic, or culture results have shown lungworms in harbor seals to be infected with brucellae, suggesting that the lungworms may serve a role in this infection. In this study, we reviewed archived and more recent case material from 5 Pacific harbor seals from Washington State (USA) with evidence of B. pinnipedialis infection in the lungworm Parafilaroides sp. Twenty-two sections of lung containing approximately 220 Parafilaroides sp., stained with an immunohistochemical technique using antibody to B. abortus, showed approximately 80 (36%) infected nematodes. A few brucellae were also present in lung parenchyma in proximity to nematodes. Infection was present in the first- and fourth-stage larvae in the seal lung and intestines, as well as in the male and female reproductive organs of adult nematodes. Infected sperm deposits in the nematode uterus were suggestive of venereal transmission between lungworms. Massive infection of some degenerate adult lungworms and evidence of degeneration of some developing larvae in utero were observed. Based on these observations, we suggest that Parafilaroides sp., rather than the Pacific harbor seal Phoca vitulina richardsi, is the preferred host of B. pinnipedialis infection.

A MALDI-TOF MS database with broad genus coverage for species-level identification of Brucella

Brucella are highly infectious bacterial pathogens responsible for a severely debilitating zoonosis called brucellosis. Half of the human population worldwide is considered to live at risk of exposure, mostly in the poorest rural areas of the world. Prompt diagnosis of brucellosis is essential to prevent complications and to control epidemiology outbreaks, but identification of Brucella isolates may be hampered by the lack of rapid and cost-effective methods. Nowadays, many clinical microbiology laboratories use Matrix-Assisted Laser Desorption Ionization–Time Of Flight mass spectrometry (MALDI-TOF MS) for routine identification. However, lack of reference spectra in the currently commercialized databases does not allow the identification of Brucella isolates. In this work, we constructed a Brucella MALDI-TOF MS reference database using VITEK MS. We generated 590 spectra from 84 different strains (including rare or atypical isolates) to cover this bacterial genus. We then applied a novel biomathematical approach to discriminate different species. This allowed accurate identification of Brucella isolates at the genus level with no misidentifications, in particular as the closely related and less pathogenic Ochrobactrum genus. The main zoonotic species (B. melitensis, B. abortus and B. suis) could also be identified at the species level with an accuracy of 100%, 92.9% and 100%, respectively. This MALDI-TOF reference database will be the first Brucella database validated for diagnostic and accessible to all VITEK MS users in routine. This will improve the diagnosis and control of brucellosis by allowing a rapid identification of these pathogens.

Brucella are bacteria that mainly infect animals. They can also be transmitted to humans and cause a serious disease called brucellosis. Half the world's population is considered exposed, especially in the poorest rural areas. Experts agree that prompt identification of Brucella isolates is essential to provide appropriate treatment to patients and to control epidemiological outbreaks. Mis-identification of these highly infectious pathogens may lead to delays in diagnosis, but also to increased risks of accidental exposure for laboratory workers. MALDI-TOF mass spectrometry is now the first line of bacterial identification in many routine diagnostic laboratories. However, not all clinical mass spectrometers can identify Brucella. In this work, we updated a database with Brucella spectra to improve the performance of MALDI-TOF mass spectrometers. These instruments will now be able to identify accurately Brucella isolates. This will greatly improve the diagnosis of brucellosis.

A single-institution experience with a brucellosis outbreak in the United States

Human cases of brucellosis in the United States are primarily limited to imported infections or reservoirs. We describe a brucellosis outbreak involving 8 patients treated at a single hospital in the United States. Standardized precautionary microbiology processes and coordinated collaboration among hospital departments and local health departments assisted in optimally managing this disease at our institution.

Brucella spp. at the Wildlife-Livestock Interface: An Evolutionary Trajectory through a Livestock-to-Wildlife "Host Jump"?

Brucella infections in wildlife have gained a lot of interest from the scientific community and different stakeholders. These interests are often different and sometimes conflicting. As a result, different management perspectives and aims have been implemented (One Health, public health, veterinary public health, maintenance of a brucellosis free status in livestock, sustainable wildlife harvesting by hunters, wildlife and environmental health). When addressing Brucella infection in wildlife, the most important features of Brucella infection should be considered and the following questions need to be answered: (1) Is Brucella infection a result of a spillover from livestock or is it a sustainable infection in one or more wildlife host species? (2) Did the epidemiological situation of Brucella infection in wildlife change over time and, if so, what are the main drivers of change and does it impact the wildlife population dynamics? (3) Does Brucella infection in wildlife represent a reservoir of Brucella strains for livestock? (4) Is Brucella infection in wildlife of zoonotic concern? These questions point to the fundamental biological question of how animal (domestic and wildlife)/Brucella spp. partnerships are established. Will we be able to decipher an evolutionary trajectory through a livestock-to-wildlife "host jump"? Whole genome sequencing and new "omics" techniques will help in deciphering the molecular basis of Brucella host preference and open new avenues in brucellosis management aimed at preventing opportunities for Brucella host jumps.