Gene expression of Toll-like receptors, cytokines and a nuclear factor and cytokine secretion in DH82 canine macrophage cells infected with Brucella canis.

Canine brucellosis caused by Brucella canis infection occurs mainly in dogs, and is a zoonotic disease that also has the possibility of infection in humans. Many studies have been conducted to understand the immunopathological mechanism of B. canis infection. However, the precise immune mechanism remains to be elucidated because compared to other Brucella spp., B. canis has different immune evasion mechanisms. In this study, gene expression levels of Toll-like receptors (TLRs) and TLR-associated molecules and cytokine production were analyzed to figure out the roles of immune-related host factors in B. canis infection. Time-dependent gene expression of TLRs (1-10) and TLR-related molecules (TNF-α, IL-5, IL-23, CCL4, CD40 and NFκ-B) and release of Th1, Th2 and Th17-related cytokines (IFN-γ, IL-1ß, IL-4, IL-6, IL-10 and IL-17A) were investigated in DH82 canine macrophages infected with B. canis. Time-dependent induction of TLRs 3, 7 and 8 was observed, and TLR 7 had the highest expression level (p <0.05). The expression levels of all TLR-related genes were significantly increased after infection. In particular, the expression of the CCL4 and IL-23 genes was highly induced. The amounts of IL-1ß, IL-6 and IL-10 were significantly increased by B. canis infection, but the amounts of IL-4 and IL-17A were not. The production of IL-1ß and IL-6 was the highest at 24 hr after B. canis infection (p <0.05). This study demonstrates that TLRs 3, 7 and 8 are prominent sites of to immune response induction with the production of related cytokines and a nuclear factor in DH82 cells infected with B. canis. These results suggest a sequential immune mechanism of B. canis infection, involving TLRs, cytokines and their associated factors.

Primary and memory immune responses against rough Brucella canis are less robust compared to smooth B. abortus and B. melitensis following intratracheal infection in mice.

Brucella canis is the cause of canine brucellosis, a globally distributed, zoonotic pathogen which primarily causes disease in dogs. B. canis is unique amongst the zoonotic Brucella spp. with its rough lipopolysaccharide, a trait typically associated with attenuation in gram-negative bacteria. Unfortunately, no vaccine is available against B. canis, and vaccine development is hampered by a limited understanding of the immune response required to combat it and the course of infection following a physiologically relevant, mucosal route of inoculation. To address these concerns and analyze the impact of the rough phenotype on the immune response, we infected mice intratracheally with rough B. canis or smooth B. melitensis or B. abortus. Bacterial colonization and histologic lesions were assessed in systemic target organs as well as locally in the lungs and draining mediastinal lymph node. Mice were also reinfected with Brucella following antibiotic treatment and cytokine production by T lymphocytes in the lung and spleen was assessed by flow cytometry to investigate the memory immune response. Despite its rough phenotype, B. canis established a persistent infection at the same level of colonization as the smooth strains. However, B. canis induced significantly less granulomatous inflammation in the spleen as well as a lack of bronchial-associated lymphoid tissue (BALT) hyperplasia in the lungs. These differences coincided with increased IL-10 and decreased IFN-γ in the spleen of B. canis-infected mice. Previous exposure to all Brucella strains provided protection against colonization following secondary challenge, although induction of IFN-γ by T lymphocytes was seen only in the lungs during B. canis infection while the smooth strains induced this cytokine in the spleen as well. Neither Brucella strain induced significant polyfunctional T lymphocytes, a potential immunomodulatory mechanism that appears to be independent of lipopolysaccharide phenotype.

First genome sequence of Chilean Brucella canis SCL strain provides insights on the epidemiology and virulence factors, explaining differences between geographical origins

BACKGROUND: Brucella canis is the etiological agent of canine brucellosis, a worldwide neglected zoonosis that constitutes one of the major infectious causes of infertility and reproductive failure in dogs. Although genomic information available for this pathogen has increased in recent years, here we report the first genome sequencing of a B. canis strain in Chile, and the differences in virulence genes with other B. canis strains. RESULTS: Genome assembly produced a total length of 3,289,216 bp, N50 of 95,163 and GC% of 57.27, organized in 54 contigs in chromosome I, and 21 contigs in chromosome II. The genome annotation identified a total of 1981 CDS, 3 rRNA and 36 tRNA in chromosome I, and 1113 CDS and 10 tRNA in chromosome II. There is little variation between the different strains and the SCL isolate. Phylogenetic analysis showed that the Chilean SCL strain is closely related to B. canis and B. suis strains. Small differences were found when compared to the Serbian isolate, but all strains shared the same recent common ancestor. Finally, changes in the sequence of some virulence factors showed that the SCL strain is similar to other South American B. canis strains. CONCLUSIONS: This work sequenced and characterized the complete genome of B. canis strain SCL, evidencing the complete presence of all the genes of the virB operon, and minor changes in outer membrane proteins and in the urease operon. Our data suggest that B. canis was introduced from North America and then spread throughout the South American continent.

Brucella ovis mutant in ABC transporter protects against Brucella canis infection in mice and it is safe for dogs.

BACKGROUND/OBJECTIVES: Vaccination is the most important tool for controlling brucellosis, but currently there is no vaccine available for canine brucellosis, which is a zoonotic disease of worldwide distribution caused by Brucella canis. This study aimed to evaluate protection and immune response induced by Brucella ovis ΔabcBA (BoΔabcBA) encapsulated with alginate against the challenge with Brucella canis in mice and to assess the safety of this strain for dogs. METHODS: Intracellular growth of the vaccine strain BoΔabcBA was assessed in canine and ovine macrophages. Protection induced by BoΔabcBA against virulent Brucella canis was evaluated in the mouse model. Safety of the vaccine strain BoΔabcBA was assessed in experimentally inoculated dogs. RESULTS: Wild type B. ovis and B. canis had similar internalization and intracellular multiplication profiles in both canine and ovine macrophages. The BoΔabcBA strain had an attenuated phenotype in both canine and ovine macrophages. Immunization of BALB/c mice with alginate-encapsulated BoΔabcBA (108 CFU) induced lymphocyte proliferation, production of IL-10 and IFN-γ, and protected against experimental challenge with B. canis. Dogs immunized with alginate-encapsulated BoΔabcBA (109 CFU) seroconverted, and had no hematologic, biochemical or clinical changes. Furthermore, BoΔabcBA was not detected by isolation or PCR performed using blood, semen, urine samples or vaginal swabs at any time point over the course of this study. BoΔabcBA was isolated from lymph nodes near to the site of inoculation in two dogs at 22 weeks post immunization. CONCLUSION: Encapsulated BoΔabcBA protected mice against experimental B. canis infection, and it is safe for dogs. Therefore, B. ovis ΔabcBA has potential as a vaccine candidate for canine brucellosis prevention.

Bruceloma hepático: manifestación infrecuente de una enfermedad endémica / Hepatic Brucelloma: uncommon manifestation of an endemic disease

Se presenta el caso de un varón de 44 años de edad, que consultó por fiebre de origen desconocido de dos semanas de evolución. Los cultivos revelaron la presencia del microorganismo Brucella Canis.

Deletion of the LuxR-type regulator VjbR in Brucella canis affects expression of type IV secretion system and bacterial virulence, and the mutant strain confers protection against Brucella canis challenge in mice.

Brucella spp. are facultative intracellular pathogens and zoonotic agents which pose a huge threat to human health and animal husbandry. The B. melitensis, B. abortus, and B. suis cause undulant fever and influenza-like symptoms in humans. However, the effects of B. canis have not been extensively studied. The quorum sensing-dependent transcriptional regulator VjbR influences the Brucella virulence in smooth type Brucella strains, such as B. melitensis, B. abortus and rough type Brucella ovis. However, the function of VjbR in the rough-type B. canis is unknown. In the present study, we discovered that deletion of this regulator significantly affected Brucella virulence in macrophage and mice infection models. The expression levels of virB operon and the ftcR gene were significantly altered in the vjbR mutant strain. We further investigated the protective effect of different doses of the vjbR mutant in mice and the results indicated that VjbR conferred protection against the virulent B. canis strain. This study presents the first evidence that the transcriptional regulator VjbR has important function in B. canis. In addition, according to its reduced virulence and the protective immunity it induces in mice, it can be a potential live attenuated vaccine against B. canis.

Characterization of Brucella canis infection in mice.

Canine brucellosis, caused by Brucella canis, is a disease of dogs and represents a public health concern as it can be transmitted to humans. Canine brucellosis is on the rise in the United States and there is currently no vaccine for use in dogs. Mice have been extensively utilized to investigate host-pathogen interactions and vaccine candidates for smooth Brucella species and could serve a similar role for studying B. canis. However, comparatively little is known about B. canis infection in mice. The objective of this study was to characterize the kinetics of colonization and pathogenicity of B. canis in mice in order to evaluate the mouse as a model for studying this pathogen. C57BL/6 mice were inoculated intraperitoneally with 105, 107, or 109 CFU of Brucella canis RM6/66 and euthanized 1-, 2-, 4-, 6-, 9-, and 12-weeks post-inoculation. B. canis induced splenomegaly in mice infected with 109 CFU at 1- and 2 weeks post-inoculation while no gross lesions were observed in other dose groups. Infection at the two higher doses resulted in dose-dependent granulomatous hepatitis and histiocytic infiltration of the spleen and mesenteric lymph nodes by 1-2 weeks. B. canis was cultured from the liver, spleen, uterus, bone marrow, lung, and kidney in all groups with colonization declining at a slow but steady rate throughout the experiment. Clearance was achieved by 9 weeks 105 CFU group and by 12 weeks in the 107 CFU group, while B. canis persisted in the spleen until 12 weeks in the highest dose group. Although B. canis does not demonstrate significant replication in C57BL/6 mice, it has the ability to establish an infection, induce splenomegaly, and persist for several weeks in multiple organs. Moreover, 1 x 107 CFU appears to be a suitable challenge dose for investigating vaccine safety.

Caracterización de la variabilidad genética de cepas de campo de Brucella canis aisladas en Antioquia / Characterization of the genetic variability of field strains of Brucella canis isolated in Antioquia

Brucella canis, un patógeno intracelular facultativo, es responsable de la brucelosis canina, una enfermedad zoonótica que afecta a los caninos y al hombre. En los primeros causa abortos y fallas reproductivas; en el ser humano genera síntomas inespecíficos. En el año 2005 se demostró la presencia de B. canis en Antioquia (Colombia). Las cepas halladas se identificaron como tipo 2. La secuenciación del genoma completo de una cepa de campo denominada Brucella canis str. Oliveri mostró indels específicos de especie; a partir de estos se buscó conocer características genómicas de las cepas de B. canis aisladas y establecer relaciones filogenéticas, así como el tiempo de divergencia de la cepa Oliveri. Se realizó PCR convencional y secuenciación de 30 cepas de campo, se identificaron 5 indels reconocidos en B. canis str. Oliveri, se empleó ADN de Brucella suis, Brucella melitensis y cepas vacunales de Brucella abortus como controles. Se determinó que las cepas de campo estudiadas comparten 4 de los 5 indels de la cepa Oliveri, lo que indica la presencia de más de una cepa de B. canis circulando en la región. El análisis filogenético se realizó con 24 cepas de Brucella mediante secuencias concatenadas de genes marcadores de especie. Se probó la hipótesis del reloj molecular y adicionalmente se realizó test de tasas relativas de Tajima. De esta manera se demostró que la cepa Oliveri, al igual que las otras cepas de B. canis analizadas, divergen de B. suis. Se rechazó la hipótesis del reloj molecular entre las especies de Brucella y se demostró una tasa de evolución y una distancia genética similar entre las cepas de B. canis.

Brucella canis is a facultative intracellular pathogen responsible for canine brucellosis, a zoonotic disease that affects canines, causing abortions and reproductive failure; and the production of non-specific symptoms in humans. In 2005 the presence of B. canis in Antioquia was demonstrated and the strains were identified as type 2. The sequencing of the genome of a field strain denoted Brucella canis str. Oliveri, showed species-specific indel events, which led us to investigate the genomic characteristics of the B. canis strain isolated and to establish the phylogenetic relationships and the divergence time of B. canis str. Oliveri. Conventional PCR sequencing was performed in 30 field strains identifying 5 indel events recognized in B. canis str. Oliveri. ADN from Brucella suis, Brucella melitensis and vaccine strains from Brucella abortus were used as control, and it was determined that all of the studied field strains shared 4 out of the 5 indels of the sequenced Oliveri strain, indicating the presence of more than one strain circulating in the region. Phylogenetic analysis was performed with 24 strains of Brucella using concatenated sequences of genetic markers for species differentiation. The molecular clock hypothesis and Tajima's relative rate test were tested, showing that the Oliveri strain, similarly to other canis species, diverged from B. suis. The molecular clock hypothesis between Brucella species was rejected and an evolution rate and a similar genetic distance between the B. canis were demonstrated.

Tissue distribution and cell tropism of Brucella canis in naturally infected canine foetuses and neonates.

Brucella canis infection is an underdiagnosed zoonotic disease. Knowledge about perinatal brucellosis in dogs is extremely limited, although foetuses and neonates are under risk of infection due to vertical transmission. In this study, immunohistochemistry was used to determine tissue distribution and cell tropism of B. canis in canine foetuses and neonates. Diagnosis of B. canis in tissues of naturally infected pups was based on PCR and sequencing of amplicons, bacterial isolation, and immunohistochemistry, whose specificity was confirmed by laser capture microdissection. PCR positivity among 200 puppies was 21%, and nine isolates of B. canis were obtained. Tissues from 13 PCR-positive puppies (4 stillborn and 9 neonates) presented widespread immunolabeling. Stomach, intestines, kidney, nervous system, and umbilicus were positive in all animals tested. Other frequently infected organs included the liver (92%), lungs (85%), lymph nodes (69%), and spleen (62%). Immunolabeled coccobacilli occurred mostly in macrophages, but they were also observed in erythrocytes, epithelial cells of gastrointestinal mucosa, renal tubules, epidermis, adipocytes, choroid plexus, ependyma, neuroblasts, blood vessels endothelium, muscle cells, and in the intestinal lumen. These results largely expand our knowledge about perinatal brucellosis in the dog, clearly demonstrating a pantropic distribution of B. canis in naturally infected foetuses and neonates.

Pigs, pooches and pasteurisation: The changing face of brucellosis in Australia

BACKGROUND: Brucellosis, also known as undulant, Mediterranean or Malta fever, is a systemic infection that causes fever, sweats, arthralgias and myalgias. A globally important disease, brucellosis is re-emerging in Australia in association with feral pig hunting activities. OBJECTIVE: This article aims to provide clinicians with an overview of brucellosis, covering epidemiology, clinical features, diagnosis, management and prevention. DISCUSSION: Brucellosis should be suspected in all patients with non-specific, flu-like illness who fall into one of the major risk groups (feral pig hunters, overseas travellers and migrants). Depression is common and often severe, relative to other symptoms. Early diagnosis and treatment are important for preventing complications, which include osteoarticular, genitourinary or, more rarely, neurological or cardiovascular diseases. Diagnosing acute infections is based on serology and blood cultures; imaging and biopsy may be required for diagnosis of focal infections. Dual therapy with doxycycline and gentamicin is the recommended treatment. Relapse occurs in up to 10% of patients. Prevention is achieved through the use of protective gear during hunting and avoidance of unpasteurised dairy products in countries where occur in animals.

The influence of canine brucellosis on morphofunctional features of epididymal spermatozoa: case report / Influência da brucelose canina nos aspectos morfofuncionais de espermatozoides epididimários: relato de caso

The present work reports a clinical case of a mongrel dog, with serological diagnosis of brucellosis, from which epididymal sperm analysis was performed. Sperm samples were collected from different segments of the epididymis (tail, corpus, and caput). Sperm samples were evaluated for computer-assisted motility analysis (CASA), spermatic morphology, mitochondrial activity and sperm plasmatic membrane and acrosomal integrity. Changes in sperm movement patterns were found (progressive motility, percentage of rapid sperm, percentage of rapid velocity, average pathway, curvilinear velocity, velocity straight line, amplitude of lateral head displacement, straightness and linearity), increase of total morphological defects (51%) and absence of sperm mitochondrial activity (20%) were verified, especially for cauda epididymides. We highlight that such changes can contribute to clinical diagnosis of Brucellosis in dogs and to the use of epididymal sperm in reproductive biotechnologies.(AU)

Relata-se o caso de um cão mestiço, com diagnóstico sorológico para brucelose canina, a partir do qual foram realizadas análises do sêmen epididimário. As amostras espermáticas foram coletadas dos diferentes segmentos epididimários (cabeça, corpo e cauda). Foram realizadas as avaliações de motilidade computadorizada do sêmen (CASA), morfologia espermática, atividade mitocondrial, integridade das membranas plasmática e acrossomal. Houve alteração no padrão de movimentação espermática (motilidade progressiva, espermatozoides rápidos, velocidade média da trajetória, velocidade curvilínea, velocidade linear progressiva, amplitude de deslocamento lateral da cabeça, retilinearidade e linearidade), aumento do total de defeitos morfológicos (51%) e da ausência de atividade mitocondrial espermática (20%) dos espermatozoides, especialmente da cauda do epidídimo. Ressalta-se que tais achados podem contribuir para o diagnóstico clínico da brucelose canina e para a utilização do sêmen epididimário em biotecnologias da reprodução.(AU)

Prevalência e fatores de risco para a leptospirose e brucelose na população canina da Estância Turística de Ibiúna, São Paulo, Brasil / Prevalence and risk factors for leptospirosis and brucellosis in the canine population of the Tourist Resort of Ibiúna, State of São Paulo, Brazil

O objetivo do trabalho foi determinar a prevalência de leptospirose e brucelose por Brucella canis e determinar os fatores de risco associados com a positividade em cães da Estância Turística de Ibiúna, estado de São Paulo, Brasil. Foram examinados 570 animais distribuídos em 4 regiões nos 48 bairros do município, no período de setembro de 2007 a março de 2008. O diagnóstico sorológico da leptospirose foi efetuado com o teste de soroaglutinação microscópica (SAM), e para o diagnóstico de brucelose foi realizado hemocultivo. Dos 570 animais examinados, 187 (32,8%; IC95% 28,9 - 36,8) foram soropositivos para leptospirose, com predomínio de reações para os sorovares Pyrogenes, Autumnalis e Canicola, e 6 (1,05%; IC95% 0,4 - 2,2) foram positivos para brucelose. A variável atividade sexual (OR = 1,73) foi identificada como fator de risco associado à positividade para leptospirose, e o manejo do tipo solto foi considerado fator de risco tanto para leptospirose (OR = 1,96) quanto para brucelose (OR = 10,85). Conclui-se que a leptospirose e a brucelose estão presentes em cães da Estância Turística de Ibiúna, São Paulo, e que a atividade sexual e o acesso irrestrito à rua são condições associadas com a prevalência das infecções.(AU)

The aim of this survey was to determine the prevalence of leptospirosis and brucellosis due to Brucella canis and to determine the risk factors associated with positivity in dogs of the Tourist Resort of Ibiúna, State of São Paulo, Brazil. A total of 570 blood samples were collected from dogs from 4 regions of 48 districts of the county of Ibiúna during the period of September 2007 to March 2008. Serological diagnosis of leptospirosis was performed with the microscopic agglutination test (MAT), and blood culture was used for the diagnosis of brucellosis. Of the 570 dogs used 187 (32.8%; 95%CI 28.9 - 36.8) were seropositive to leptospirosis, with predominance of reactions to serovars Pyrogenes, Autumnalis and Canicola, and 6 (1.05%; 95%CI 0.4 - 2.2) were positive to brucellosis. Variable sexual activity (OR = 1.73) was identified as risk factor associated with the positivity to leptospirosis, and free access to street was considered risk factor for both leptospirosis (OR = 1.96) and brucellosis (OR = 10.85). It is concluded that leptospirosis and brucellosis are present in dogs of the Tourist Resort of Ibiúna, State of São Paulo, and sexual activity and free access to street are conditions associated with the prevalence of infections.(AU)

Brucella canis is an intracellular pathogen that induces a lower proinflammatory response than smooth zoonotic counterparts.

Canine brucellosis caused by Brucella canis is a disease of dogs and a zoonotic risk. B. canis harbors most of the virulence determinants defined for the genus, but its pathogenic strategy remains unclear since it has not been demonstrated that this natural rough bacterium is an intracellular pathogen. Studies of B. canis outbreaks in kennel facilities indicated that infected dogs displaying clinical signs did not present hematological alterations. A virulent B. canis strain isolated from those outbreaks readily replicated in different organs of mice for a protracted period. However, the levels of tumor necrosis factor alpha, interleukin-6 (IL-6), and IL-12 in serum were close to background levels. Furthermore, B. canis induced lower levels of gamma interferon, less inflammation of the spleen, and a reduced number of granulomas in the liver in mice than did B. abortus. When the interaction of B. canis with cells was studied ex vivo, two patterns were observed, a predominant scattered cell-associated pattern of nonviable bacteria and an infrequent intracellular replicative pattern of viable bacteria in a perinuclear location. The second pattern, responsible for the increase in intracellular multiplication, was dependent on the type IV secretion system VirB and was seen only if the inoculum used for cell infections was in early exponential phase. Intracellular replicative B. canis followed an intracellular trafficking route undistinguishable from that of B. abortus. Although B. canis induces a lower proinflammatory response and has a stealthier replication cycle, it still displays the pathogenic properties of the genus and the ability to persist in infected organs based on the ability to multiply intracellularly.

Booster vaccination with safe, modified, live-attenuated mutants of Brucella abortus strain RB51 vaccine confers protective immunity against virulent strains of B. abortus and Brucella canis in BALB/c mice.

Brucella abortus attenuated strain RB51 vaccine (RB51) is widely used in prevention of bovine brucellosis. Although vaccination with this strain has been shown to be effective in conferring protection against bovine brucellosis, RB51 has several drawbacks, including residual virulence for animals and humans. Therefore, a safe and efficacious vaccine is needed to overcome these disadvantages. In this study, we constructed several gene deletion mutants (ΔcydC, ΔcydD and ΔpurD single mutants, and ΔcydCΔcydD and ΔcydCΔpurD double mutants) of RB51 with the aim of increasing the safety of the possible use of these mutants as vaccine candidates. The RB51ΔcydC, RB51ΔcydD, RB51ΔpurD, RB51ΔcydCΔcydD and RB51ΔcydCΔpurD mutants exhibited significant attenuation of virulence when assayed in murine macrophages in vitro or in BALB/c mice. A single intraperitoneal immunization with RB51ΔcydC, RB51ΔcydD, RB51ΔcydCΔcydD or RB51ΔcydCΔpurD mutants was rapidly cleared from mice within 3 weeks, whereas the RB51ΔpurD mutant and RB51 were detectable in spleens until 4 and 7 weeks, respectively. Vaccination with a single dose of RB51 mutants induced lower protective immunity in mice than did parental RB51. However, a booster dose of these mutants provided significant levels of protection in mice against challenge with either the virulent homologous B. abortus strain 2308 or the heterologous Brucella canis strain 26. In addition, these mutants were found to induce a mixed but T-helper-1-biased humoral and cellular immune response in immunized mice. These data suggest that immunization with a booster dose of attenuated RB51 mutants provides an attractive strategy to protect against either bovine or canine brucellosis.

Evidence for unapparent Brucella canis infections among adults with occupational exposure to dogs.

Human serological assays designed to detect brucellosis will miss infections caused by Brucella canis, and low levels of periodic bacteremia limit diagnosis by blood culture. Recent B. canis outbreaks in dogs and concomitant illnesses in caretakers suggest that unapparent human infections may be occurring. With more than a quarter of a million persons in occupations involving dogs, and nearly 80 million dog owners in the United States, this pathogen is an under-recognized human health threat. To investigate occupational exposure to B. canis, we adapted a commercial canine serological assay and present the first controlled seroepidemiological study of human B. canis infections in recent years. 306 adults with occupational exposure to dogs and 101 non-matched, non-canine-exposed subjects were enrolled. Antibodies were detected using the canine D-Tec(®) CB rapid slide agglutination test (RSAT) kit with a secondary 2-mercaptoethanol (ME)-RSAT. Results were validated on a blinded subset of sera with an additional RSAT and indirect enzyme-linked immunoassay at the National Administration of Laboratories and Health Institutes (ANLIS) in Argentina. Seroprevalence ranged from 10.8% (RSAT) to 3.6% (ME-RSAT) among canine-exposed subjects. Kennel employees were more likely to test RSAT seropositive compared with other canine exposures (OR = 2.7; 95% CI, 1.3-5.8); however, low seroprevalence limited meaningful occupational risk factor analyses. Two seropositive participants reported experiencing symptoms consistent with brucellosis and having exposure to B. canis-infected dogs; however, temporality of symptom onset with reported exposure could not be determined. D-Tec(®) CB results had substantial agreement with ANLIS assays (Cohen's kappa = 0.60-0.68). These data add to a growing body of literature suggesting that people occupationally exposed to dogs may be at risk of unapparent B. canis infection. It seems prudent to consider B. canis as an occupational public health concern and encourage the development of serological assays to detect human B. canis infections.

Infección por Brucella canis en humanos: propuesta de un modelo teórico de infección a través de la ruta oral / Brucella canis infection in humans: Proposal of a theoretical model of infection through the oral route

La infección por Brucella canis en los humanos se ha reconocido recientemente como una zoonosis, pero frecuentemente es sub reportada debido a que los síntomas pueden confundirse con los de un resfriado común u otras infecciones causadas por otros patógenos. Los caninos son los hospederos primarios de Brucella canis ; el incremento en la tendencia de tener perros como mascotas podría también aumentar la posibilidad de transmisión de la infección a los humanos por el estrecho contacto entre la mascota infectada y su propietario. En Colombia, hay reportes de aislamientos de B. canis de caninos de criaderos y de un humano en contacto con perros infectados, al igual que reportes de caninos seropositivos a la infección. Sin embargo, no hay mucha información disponible sobre los mecanismos de interacción hospedero-patógeno que conduzcan al establecimiento de la infección por Brucella canis en perros y en humanos esta información es todavía menor. En esta revisión se propone un modelo para la infección humana con Brucella canis a través de la ruta oral utilizando la información disponible para otras especies de Brucella que infectan al humano, incluyendo B. abortu s y B. melitensis , que difieren de B. canis en la composición estructural de su lipopolisacárido. También se hipotetiza el mecanismo de infección celular que es usado por B. canis para invadir y establecer la infección en células no fagocíticas y fagocíticas.

Brucella canis infection in humans has recently been recognized as a zoonosis, but it is frequently under reported because the flu-like symptoms are often confused with the presence of other disease-causing pathogens. Dogs are the primary hosts for Brucella canis ; the increasing trend to adopt dogs as pets also enhances the likelihood of transmission of Brucella canis infection through contact between infected dogs and owners. In Colombia, there are reports of isolates of B. canis from kennel dogs and also from one human being along with seropositive results from dogs and humans. However, the mechanism of hostpathogen interactions leading to the infection of Brucella canis in dogs is still unknown and even less is known about human infections. This review proposes a model for human infection with Brucella canis through the oral route. We use the information available for other human-infecting Brucella species, including B. abortu s and B. melitensis, which differ from B. canis in the structural composition of the lipopolysaccharide molecule. The mechanism of cellular infection used by B. canis to invade and establish infection in nonphagocytic and phagocytic cells is also hypothesized.

Factores asociados con la seropositividad a Brucella canis en criaderos caninos de dos regiones de Antioquia, Colombia / Factors associated with Brucella canis seropositivity in kennels of two regions of Antioquia, Colombia / Fatores associados à soropositividade por Brucella canis em cães reprodutores em duas regiões no Estado de Antioquia, Colômbia

El objetivo fue determinar la seroprevalencia a Brucella canis en perros y humanos convivientes en criaderos caninos y explorar los factores de riesgo asociados a la seropositividad. Se tomaron 20 criaderos, en los cuales se realizó diagnóstico serológico por PARP-2ME de 428 caninos y 91 humanos. Se aplicó una encuesta para determinar los factores de riesgo y se analizaron los datos mediante regresión logística. Se determinó una seroprevalencia de 15% en caninos y 9% en humanos convivientes. Se determinaron como factores asociados a la seropositividad canina el historial de seropositividad canina, conservar los caninos seropositivos, historial de aborto, higiene y protección del operario deficientes durante el servicio reproductivo, y procedimiento inseguro durante la atención de abortos. Como factores protectores se establecieron la ubicación rural de los criaderos, facilidad de aseo de los caniles, PARP-2ME premonta, y procedimiento seguro durante la atención de partos. En humanos se determinaron factores asociados: criaderos ubicados en el Valle Aburrá y de tipo urbano.

The objectives of this study were to determine Brucella canis seroprevalence in dogs and in humans living near kennels and to explore risk factors associated with seropositivity. Twenty kennels were included in a serological survey with RSAT-2ME, and samples were collected from 428 dogs and 91 humans. An interview was applied to determine risk factors, and the data were analyzed using logistic regression. Seroprevalence was 15% in dogs and 9% in humans. Factors associated with current canine seropositivity were: history of canine seropositivity, non-culling of seropositive dogs, history of abortion, poor hygiene and personal protection during reproductive service, and unsafe procedures during care for abortions. Protective factors included: rural location of kennels, ease of cleaning kennels, pre-mating RSAT-2ME, and safe procedures during care for delivery. Factors associated with seropositive status in humans were: kennels located in Valle de Aburrá and urban location.

O objetivo desta pesquisa foi determinar a soroprevalência de brucelose dada por Brucella canis na população canina e os seres humanos que moram junto com os cães reprodutores, e explorar os fatores de risco associados à soropositividade.Vinte cães foram amostrados, nestes se fez o diagnóstico sorológico por PARP-2ME para 428 caninos e 91 pessoas. Para o estudo de fatores de risco associados à doença foi realizada uma análise por regressão logística. Encontrou-se uma soroprevalência de 15% e 9% nos caninos e humanos, respectivamente. Foram identificados como fatores de risco associados à soropositividade canina nos canis avaliados a história clínica com antigos diagnósticos de abortos e de soropositividade, conservar caninos que sejam soropositivos, a má higiene no canil e uma indumentária laboral insuficiente para o trabalhador que mexe com os cães, tanto durante o serviço reprodutivo quanto na atenção de abortos que possam ser inseguros. Encontraram-se como fatores de proteção nesta pesquisa as regiões rurais onde estava a incubadora, a facilidade de limpeza que possibilita uma melhor higiene dos canis, PARP-2ME pré-nupcial e procedimento seguro durante o parto. Em humanos foram determinados como fatores associados: criadores localizados no Valle Aburrá e do tipo urbano.

Detección de Brucella canis por método de inmunocromatografía en perros vagos capturados en la ciudad de Temuco, Chile, 2011 / Detection of Brucella canis by immunochromatography method in vague dogs captured in Temuco city, Chile, 2011

Background: Brucella canis is responsible for brucellosis in dogs, causing reproductive disorders and is considered a zoonoses, as described in several countries. The epidemiological data are scarce in our country. Aim: To determine the prevalence of Brucella canis in vague dogs in Temuco city and housed in the Temuco Kennel. Methods: Quantitative and cross-section study. We used 400 samples of dogs of both sexes, different ages and mainly mixed race, which were tested by immunochromatography. Results: Antibodies were detected in 4 samples Brucella canis which represented 1% of the population studied, 2 females (0.5%) and 2 males (0.5%). Discussion: We conclude that dogs are infected by B. canis in a low range but remains a risk condition to the health of the human population if not maintained adequate sanitary control of pets, like vague dogs.

Introducción: Brucella canis es responsable de la brucelosis en perros, provocándoles trastornos reproductivos y es considerada una zoonosis, ya descrita en varios países. Los datos epidemiológicos en nuestro medio son exiguos. Objetivo: Determinar la prevalencia de B. canis en perros vagos capturados en la ciudad de Temuco y albergados en el Canil Temuco. Materialy Métodos: Estudio de tipo cuantitativo y de corte transversal. Se utilizaron 400 muestras de perros de ambos sexos, diferentes edades y principalmente mestizos, procesadas mediante la prueba de inmunocromatografía. Resultados: Se detectaron anticuerpos anti-B. canis en 4 muestras lo cual representó 1% de la población estudiada, 2 hembras (0,5%) y 2 machos (0,5%). Conclusión: El hallazgo de perros serológicamente positivos a B. canis, es baja pero no deja de ser un indicador del riesgo en el que se encuentra la salud de la población humana si no se mantiene un adecuado control sanitario de las mascotas, como ocurre con los perros vagos.

Endocarditis por Brucella canis: primer caso documentado en un paciente adulto en Argentina / [Brucella canis endocarditis: first documented case in Argentina].

We herein present the case of an adult male patient who consulted for lower extremity edema, a 2- month history of fever and oppressive chest pain radiating to the left arm. He referred neither contact with breeding animals nor consumption of unpasteurized dairy products. A diagnosis of endocarditis was confirmed by cardiac studies. Since the empirical treatment with cephalotin, ampicillin and gentamicin failed, the patient underwent aortic valve replacement. A total of four blood cultures were positive with a gram-negative rod. Bacterial identification was performed using the API 20 NE technique (bioMÞrieux), the Phoenix automated method (BD) and conventional biochemical tests which were unable to classify the isolate as to genus and species. The strain was sent to the INEI-ANLIS "Dr. Carlos G. Malbrán" where it was identified as Brucella canis. The antimicrobial treatment was switched to doxycycline, rifampicin and trimethoprim-sulfamethoxazole with good evolution of the patient. The clinical significance of this case report lies in the possible failure of the empiric antibiotic therapy administered for endocarditis, since B. canis did not respond to the conventional antimicrobial treatment for this pathology.

Differential expression of iron acquisition genes by Brucella melitensis and Brucella canis during macrophage infection.

Brucella spp. cause chronic zoonotic disease often affecting individuals and animals in impoverished economic or public health conditions; however, these bacteria do not have obvious virulence factors. Restriction of iron availability to pathogens is an effective strategy of host defense. For brucellae, virulence depends on the ability to survive and replicate within the host cell where iron is an essential nutrient for the growth and survival of both mammalian and bacterial cells. Iron is a particularly scarce nutrient for bacteria with an intracellular lifestyle. Brucella melitensis and Brucella canis share ~99% of their genomes but differ in intracellular lifestyles. To identify differences, gene transcription of these two pathogens was examined during infection of murine macrophages and compared to broth grown bacteria. Transcriptome analysis of B. melitensis and B. canis revealed differences of genes involved in iron transport. Gene transcription of the TonB, enterobactin, and ferric anguibactin transport systems was increased in B. canis but not B. melitensis during infection of macrophages. The data suggest differences in iron requirements that may contribute to differences observed in the lifestyles of these closely related pathogens. The initial importance of iron for B. canis but not for B. melitensis helps elucidate differing intracellular survival strategies for two closely related bacteria and provides insight for controlling these pathogens.