RESUMEN
The early host response during pulmonary nocardiosis is highly dependent on neutrophils and the successful clearance of bacteria in tissue. The data presented in this study showed that IL-17 mediated the neutrophil response following intranasal inoculation with Nocardia asteroides strain GUH-2. Flow cytometry revealed that neutrophil levels in C57BL/6 mice were increased by day 1 post inoculation and remained elevated until day 3, during which time the majority of bacterial clearance occurred. Intracellular cytokine staining for IL-17 showed a 3.5- to 5-fold increase in IL-17 producing T-lymphocytes that were predominately comprised by CD4(-)CD8(-) γδ T-lymphocytes. The importance of IL-17 and γδ T-cells was determined by the in vivo administration of antibody, capable of blocking IL-17 binding or TCR δ, respectively. Neutralization of either IL-17 or γδ T-cells in Nocardia treated mice resulted in attenuated neutrophil infiltration. Paralleling this impaired neutrophil recruitment, nearly a 10-fold increase in bacterial burden was observed in both anti-IL-17 and anti-TCR δ treated animals. Together, these data indicate a protective role for IL-17 and suggest that IL-17 producing γδ T-lymphocytes contribute to neutrophil infiltration during pulmonary nocardiosis.
Asunto(s)
Interleucina-17/inmunología , Neutrófilos/inmunología , Nocardiosis/inmunología , Nocardia asteroides/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Subgrupos de Linfocitos T/inmunología , Animales , Femenino , Inmunidad Innata , Interleucina-17/metabolismo , Pulmón/inmunología , Pulmón/microbiología , Ratones , Ratones Endogámicos C57BL , Infiltración Neutrófila/inmunología , Neutrófilos/metabolismo , Nocardiosis/microbiología , Nocardia asteroides/crecimiento & desarrollo , Receptores de Antígenos de Linfocitos T gamma-delta/metabolismo , Subgrupos de Linfocitos T/metabolismoRESUMEN
The pathogenic strain Nocardia cyriacigeorgica GUH-2 was isolated from a fatal human nocardiosis case, and its genome was sequenced. The complete genomic sequence of this strain contains 6,194,645 bp, an average G+C content of 68.37%, and no plasmids. We also identified several protein-coding genes to which N. cyriacigeorgica's virulence can potentially be attributed.
Asunto(s)
Genoma Bacteriano , Nocardiosis/microbiología , Nocardia/clasificación , Nocardia/genética , Animales , Regulación Bacteriana de la Expresión Génica , Humanos , Datos de Secuencia MolecularRESUMEN
Nocardia asteroides (Nocardia cyriacigeorgica) strain GUH-2 infects the brains of mice following intravenous injection. Non-lethal infections resulted in a transitory increase of bacterial numbers in the brain followed by the development of permanent impaired movements at a time when bacteria appeared to be eliminated from the brain. These signs included headshake, rigidity, stooped posture, dyskinesia, retropulsion, and abnormal tail positioning in approximately 20% of infected animals. The attached video presents a typical mouse following infection with this organism, as compared to an age- and gender-matched uninfected control mouse.
Asunto(s)
Encefalitis/complicaciones , Encefalitis/microbiología , Enfermedad de la Neurona Motora/microbiología , Nocardiosis/complicaciones , Nocardiosis/microbiología , Nocardia asteroides/fisiología , Animales , Encéfalo/microbiología , Femenino , Ratones , Ratones Endogámicos BALB CRESUMEN
We describe here the first case of Nocardia nova spondylodiscitis accompanied by a psoas abscess due to spreading from pulmonary nocardiosis. Nocardia was cultured from all affected sites. After 1 year of an appropriate antimicrobial therapy and a surgical drainage of the abscess that was required, the patient's clinical condition had improved.
Asunto(s)
Discitis/microbiología , Nocardiosis/complicaciones , Absceso del Psoas/microbiología , Adulto , Discitis/diagnóstico por imagen , Femenino , Humanos , Vértebras Lumbares/diagnóstico por imagen , Imagen por Resonancia Magnética , Nocardia/clasificación , Nocardia/aislamiento & purificación , Nocardiosis/microbiología , Absceso del Psoas/diagnóstico por imagen , Radiografía , Tomógrafos Computarizados por Rayos XRESUMEN
Many bacterial pathogens have the ability to induce apoptosis in their hosts. It was previously shown that Nocardia asteroides strain GUH-2, a Gram-positive facultatively intracellular pathogen, is capable of inducing the apoptotic death of dopaminergic cells in the murine brain and in PC12 cells, a rat cell line. In this study, the apoptosis-inducing potential of N. asteroides GUH-2 was further explored using HeLa cells, a human epithelial cell line. HeLa cells were incubated for 5h with live nocardiae, heat-killed bacteria, or unconcentrated nocardial culture filtrate, and changes to the cells were monitored. Consistent with the previous studies, N. asteroides GUH-2 induced DNA fragmentation and apoptosis in HeLa cells. Caspase activation and disruption of the mitochondrial membrane potential were also investigated to determine their roles in the induction of cell death. In all these experiments, significant changes were only induced by live nocardiae. A recent publication demonstrated that systemic administration of proteasome inhibitors can induce a Parkinsonian syndrome in rats that includes intraneuronal inclusions and characteristic behavioral alterations. Similar effects have been observed in mice and monkeys infected with N. asteroides GUH-2. In addition, some reports have shown that proteasome inhibition causes apoptotic death of affected cells. We therefore investigated the ability of N. asteroides GUH-2 to inhibit proteasome activity. Proteasome activity was significantly reduced, suggesting that this mechanism may be involved in the induction of apoptosis by these bacteria.
Asunto(s)
Apoptosis , Proteínas Bacterianas/metabolismo , Nocardiosis/microbiología , Nocardia asteroides/fisiología , Complejo de la Endopetidasa Proteasomal/metabolismo , Células HeLa , HumanosRESUMEN
Apoptosis, or programmed cell death, is normally responsible for the orderly elimination of aged or damaged cells, and is a necessary part of the homeostasis and development of multicellular organisms. Some pathogenic bacteria can disrupt this process by triggering excess apoptosis or by preventing it when appropriate. Either event can lead to disease. There has been extensive research into the modulation of host cell death by microorganisms, and several reviews have been published on the phenomenon. Rather than covering the entire field, this review focuses on the dysregulation of host cell apoptosis by members of the order Actinomycetales, containing the genera Corynebacterium, Mycobacterium, Rhodococcus, and Nocardia.
Asunto(s)
Infecciones por Actinomycetales/complicaciones , Actinomycetales/patogenicidad , Apoptosis/fisiología , Células Eucariotas/microbiología , Animales , Corynebacterium diphtheriae/patogenicidad , Corynebacterium diphtheriae/fisiología , Humanos , Modelos Biológicos , Mycobacterium avium/patogenicidad , Mycobacterium avium/fisiología , Mycobacterium bovis/patogenicidad , Mycobacterium bovis/fisiología , Mycobacterium tuberculosis/patogenicidad , Mycobacterium tuberculosis/fisiología , Nocardia/patogenicidad , Nocardia/fisiología , Rhodococcus/patogenicidad , Rhodococcus/fisiologíaRESUMEN
Systemic infection of BALB/c mice with Nocardia asteroides strain GUH-2 results in widespread replication of the organism in the brain, followed by its immune-mediated clearance. The present study compared the sensitivity of polymerase chain reaction (PCR) to bacterial culture for detection of cerebral nocardial infection in this experimental system. Mice (n=4/time point) were administered N. asteroides by intravenous injection, and brain specimens were evaluated for Nocardia by PCR and culture at post-infection days 2, 7, 14 and 21. Nocardia was detected by PCR in all infected animals on post-infection days 2, 7, and 14, and in one of four mice on post-infection day 21; in contrast, the organism was detected by culture only on post-infection days 2 and 7. These findings suggest that PCR may be more sensitive than culture for the detection of low numbers of Nocardia in the brain.
Asunto(s)
Encéfalo/microbiología , Infecciones Bacterianas del Sistema Nervioso Central/microbiología , Nocardia asteroides , Reacción en Cadena de la Polimerasa/métodos , Animales , Técnicas Bacteriológicas , Medios de Cultivo , Femenino , Ratones , Ratones Endogámicos BALB C , Nocardiosis/microbiología , Nocardia asteroides/genética , Nocardia asteroides/crecimiento & desarrollo , Nocardia asteroides/aislamiento & purificación , Sensibilidad y EspecificidadRESUMEN
Experimental infection of BALB/c mice with the Gram-positive bacterium Nocardia asteroides (strain GUH-2) results in life-long movement abnormalities including head shaking and spinning when held by the tail. The head shaking is temporarily inhibited by treatment with dopamine's precursor levodopa, suggesting that abnormalities in dopaminergic neurotransmission may be involved in these movement abnormalities. Cell-free filtrates from N. asteroides cultures induce > 70% dopamine depletion in rat pheochromocytoma PC12 cells, suggesting that Nocardia's effects on dopamine neurons may result in part from secreted factors. The nature of this dopamine-depleting activity was examined in the present study. Dopamine-depleting activity in N. asteroides culture filtrate was resistant to heat (100 degrees C x 30 min), proteases, and chloroform extraction, and was present in a low molecular mass (< 3 kDa) fraction. It was partially inhibited by decreasing (to 4.0) or increasing (to 10.0) the filtrate pH. GUH-2 filtrate increased cellular lactate dehydrogenase release by only 2%, and induced apoptotic morphology in only 11% of PC12 cells, suggesting that dopamine-depleting activity was not due to either cell injury or induction of apoptosis. These results suggest that a protease-resistant, low molecular mass substance secreted by N. asteroides may be responsible for its dopamine-depleting effects.
Asunto(s)
Dopamina/metabolismo , Nocardia asteroides/metabolismo , Células PC12/microbiología , Animales , Medios de Cultivo , Ratones , Ratones Endogámicos BALB C , Nocardia asteroides/enzimología , RatasRESUMEN
As current research illuminates the dynamic interplay between the innate and acquired immune responses, the interaction and communication between these two arms has yet to be fully investigated. Polymorphonuclear neutrophils (PMNs) and interferon-gamma (IFN-gamma) are known critical components of innate and acquired immunity, respectively. However, recent studies have demonstrated that these two components are not entirely isolated. Treatment of PMNs with IFN-gamma elicits a variety of responses depending on stimuli and environmental conditions. These responses include increased oxidative burst, differential gene expression, and induction of antigen presentation. Many of these functions have been overlooked in PMNs, which have long been classified as terminal phagocytic cells incapable of protein synthesis. As this review reports, the old definition of the PMN is in need of an update, as these cells have demonstrated their ability to mediate the transition between the innate and acquired immune responses.
Asunto(s)
Interferón gamma/inmunología , Activación Neutrófila/inmunología , Quimiocinas/biosíntesis , Citotoxicidad Inmunológica , Humanos , Neutrófilos/inmunología , Fagocitosis/inmunología , Transducción de Señal/inmunologíaRESUMEN
Experimental infection of BALB/c mice with the gram-positive bacterium Nocardia asteroides produces marked loss of nigrostriatal dopamine neurons, resulting in striatal dopamine depletion. To investigate the mechanism(s) responsible for this neuronal loss, we evaluated the influence of N. asteroides cell-free culture filtrates on rat pheochromocytoma PC12 cells, an in vitro model for dopamine neurons. Changes in cell viability and cell numbers were minimal after 24 h, but increased with longer incubation. In contrast, dopamine depletion occurred after 30 min incubation, and was greater with GUH-2 filtrate than with filtrate from the less virulent strain 10905. Incubation with the culture filtrate decreased viability in neuroblastoma and glioma cell lines, indicating that cytotoxic effects were not limited to dopaminergic cells. These findings suggest that the loss of nigrostriatal dopamine neurons and concomitant striatal dopamine depletion in Nocardia-infected mice may be due, at least in part, to the neurotoxicity of nocardial secretory products.
Asunto(s)
Factores Biológicos/toxicidad , Dopamina/metabolismo , Neuronas/efectos de los fármacos , Neurotoxinas/toxicidad , Nocardia asteroides/metabolismo , Animales , Factores Biológicos/metabolismo , Catecolaminas/metabolismo , Supervivencia Celular/efectos de los fármacos , Medios de Cultivo , Filtración , Neuroglía/citología , Neuroglía/efectos de los fármacos , Neuronas/citología , Neuronas/metabolismo , Neurotoxinas/metabolismo , Nocardia asteroides/aislamiento & purificación , Células PC12 , Ratas , Factores de TiempoRESUMEN
Nocardia transvalensis is a rarely reported cause of clinically significant disease, and, to our knowledge, has not been reported previously as a cause of infection in the cardiac transplant population. We report a case of N transvalensis new taxon-2 pulmonary infection that disseminated to the brain and skin in a cardiac transplant recipient despite adequate sulfonamide serum levels. Subsequent isolates were resistant to sulfonamides, and molecular ribotyping of the primary and subsequent isolates confirmed that these were the same N transvalensis new taxon-2 strain. The taxonomic and diagnostic considerations, as well as the clinical significance of anti-microbial-resistant nocardia, are reviewed and discussed herein.
Asunto(s)
Antibacterianos/uso terapéutico , Cardiomiopatía Dilatada/cirugía , Resistencia a Medicamentos , Trasplante de Corazón/efectos adversos , Nocardiosis/tratamiento farmacológico , Nocardiosis/etiología , Nocardia/patogenicidad , Evaluación de Resultado en la Atención de Salud , Complicaciones Posoperatorias , Sulfonamidas/uso terapéutico , Combinación Amoxicilina-Clavulanato de Potasio/uso terapéutico , Ceftriaxona/uso terapéutico , Ciprofloxacina/uso terapéutico , Humanos , Masculino , Persona de Mediana Edad , Nocardia/efectos de los fármacosRESUMEN
Our previous studies found that experimental infection of BALB/c mice with the Gram-positive bacterium Nocardia asteroides induced a parkinsonian-type syndrome with levodopa-responsive movement abnormalities, loss of nigrostriatal dopaminergic neurons, depletion of striatal dopamine, and intraneuronal inclusions in the substantia nigra (SN) with an appearance similar to Lewy bodies. In the present study, an in situ hybridization technique was developed to detect nocardial 16S ribosomal RNA (rRNA), using a Nocardia-specific probe (B77). Cerebral cortical specimens from cynomolgus monkeys were examined for the presence of nocardial RNA 48 h, 3.5 months, and 1 year after experimental infection with N. asteroides. Hybridization reactions were detected within Nocardia-like structures 48 h after infection and within intracellular inclusion bodies (immunoreactive for alpha-synuclein and ubiquitin) in one of two 3.5-month-infected monkeys. The in situ hybridization procedure was then applied in a blinded fashion to 24 human SN specimens with Lewy bodies and 11 human SN specimens without Lewy bodies (including five normal controls). Hybridization reactions were detected in nine Lewy body-containing specimens and none of the others. Reactivity was limited to inclusions with the appearance of Lewy bodies, with the exception of one specimen in which intracellular reactivity was also observed in Nocardia-like structures. These results suggest a possible association between Nocardia and neurodegenerative disorders in which Lewy bodies are present.
Asunto(s)
Encéfalo/microbiología , Cuerpos de Inclusión/microbiología , Cuerpos de Lewy/microbiología , Nocardiosis/patología , ARN Complementario , ARN Ribosómico 16S/aislamiento & purificación , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/microbiología , Animales , Encéfalo/patología , Encéfalo/ultraestructura , Femenino , Humanos , Inmunohistoquímica , Hibridación in Situ , Cuerpos de Lewy/patología , Enfermedad por Cuerpos de Lewy/microbiología , Macaca fascicularis , Masculino , Persona de Mediana Edad , Nocardia asteroides/aislamiento & purificaciónRESUMEN
Nocardia asteroides causes an acute, necrotizing pneumonia characterized by extensive infiltration of polymorphonuclear neutrophils (PMNs) into the lungs. Although PMNs have historically been classified as end-point cells, recent investigations have indicated that PMNs have the ability to secrete cytokines such as interleukin (IL)-4 and IL-12. This study investigated the ability of PMNs to produce cytokines in a murine model of N. asteroides pulmonary infection. Flow cytometric analysis demonstrated the production of interferon-gamma (IFN-gamma), but not IL-4, by PMNs in response to this infection. IFN-gamma production correlated with peak infiltration of PMNs into the lungs. Cell sorting and enzyme-linked immunosorbent assay were used to confirm cytokine production by cells with nuclear morphology characteristic of PMNs. This is the first report of IFN-gamma production by neutrophils in response to an infection in vivo. These results suggest that PMNs play an important role in directing the host toward a T helper cell type 1 phenotypic response in the lungs.
Asunto(s)
Interferón gamma/biosíntesis , Nocardiosis/inmunología , Nocardia asteroides/inmunología , Neumonía Bacteriana/inmunología , Animales , Ensayo de Inmunoadsorción Enzimática , Femenino , Expresión Génica , Interferón gamma/genética , Interleucina-4/análisis , Ratones , Ratones Endogámicos C57BL , Nocardiosis/microbiología , Nocardiosis/patología , Nocardia asteroides/aislamiento & purificación , Neumonía Bacteriana/microbiología , Neumonía Bacteriana/patología , Organismos Libres de Patógenos Específicos , Factores de TiempoRESUMEN
Helicobacter cinaedi may cause proctocolitis or bacteremia in homosexual men infected with human immunodeficiency virus or occasionally in other immunocompromised hosts. There are scattered reports of H. cinaedi isolated from a variety of animal hosts, but to date only hamsters have been found to be a common natural reservoir. Microaerophillic cultures of feces from 5 of 16 asymptomatic rhesus monkeys (Macaca mulatta) (31%) were positive for a curved gram-negative rod. A polyphasic taxonomic approach was used to identify the organism as H. cinaedi. These results show that H. cinaedi frequently colonizes asymptomatic captive rhesus monkeys, which may serve as another potential reservoir for human infection.
Asunto(s)
Animales de Laboratorio , Infecciones por Helicobacter/veterinaria , Helicobacter/clasificación , Helicobacter/aislamiento & purificación , Macaca mulatta , Enfermedades de los Monos/microbiología , Animales , Técnicas de Tipificación Bacteriana , Medios de Cultivo , ADN Ribosómico/análisis , ADN Ribosómico/genética , Heces/microbiología , Femenino , Genotipo , Helicobacter/genética , Helicobacter/metabolismo , Helicobacter/ultraestructura , Infecciones por Helicobacter/microbiología , Masculino , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , ARN Ribosómico 23S/genética , Análisis de Secuencia de ADNRESUMEN
Os autores, em um período de 10 anos (1976/1986) realizaram um estudo clínico, histopatológico e micológico em 47 casos de actinomicetoma. Os agentes etiológicos isolados foram: Actinomadura madurae - 20 casos (42,5%); Nocardia brasiliensis - 13 casos (27,6%); Nocardia spp - 7 casos (14,8%); Streptomyces somaliensis - 4 casos (8,5%); Nocardia asteroides - 2 casos (4,2%) e N. otitidis caviarum (N. caviae) - 1 caso (2,1%). A maioria dos casos procedia de zona rural, prevalecendo a infecçäo no sexo masculino (4:1). A idade dos pacientes variou de 18 a 80 anos. Dos 47 casos registrados, 24 foram observados no Estado de Lara, representando 51% do total das observaçöes