RESUMO
Bacillus subtilis subsp. subtilis G7 was isolated from a deep-sea hydrothermal vent and is pathogenic to pathogenic to fish (Japanese flounder) and mice. G7 is able to survive in host sera and phagocytes. In this study, we investigated the underlying mechanism of G7 serum resistance. We found that (i) the remaining complement activity was very low in G7-incubated flounder serum but high in G7-incubated mouse serum; (ii) cleaved C3 and C5 components were detected on flounder serum-incubated G7 but not on mouse serum-incubated G7; (iii) abundant uncleaved C5 was localized in G7-incubated mouse, but not flounder, serum; (iv) G7-incubated flounder, but not mouse, serum exhibited strong chemotactic activity; (v) pre-treatment with low-dose lysozyme abolished the serum resistance of G7. Hence, G7 activates flounder complement but is protected from complement-mediated destruction by its cell wall structure, while G7 prevents the activation of mouse complement. These results indicate that G7 employs different mechanisms to avoid the complement killing of different hosts.
Assuntos
Infecções por Bacillaceae/imunologia , Bacillus subtilis/imunologia , Proteínas do Sistema Complemento/imunologia , Doenças dos Peixes/imunologia , Linguado/imunologia , Evasão da Resposta Imune/imunologia , Animais , Infecções por Bacillaceae/sangue , Infecções por Bacillaceae/microbiologia , Bacillus subtilis/isolamento & purificação , Bacillus subtilis/patogenicidade , Western Blotting , Ensaio de Imunoadsorção Enzimática , Doenças dos Peixes/microbiologia , Linguado/sangue , Linguado/microbiologia , Interações Hospedeiro-Patógeno/imunologia , Fontes Hidrotermais/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Células RAW 264.7 , Virulência/imunologiaAssuntos
Infecções por Bacillaceae/imunologia , Bacillus cereus , Citocinas/sangue , Recém-Nascido de Peso Extremamente Baixo ao Nascer , Doenças do Prematuro/imunologia , Infecções Oportunistas/imunologia , Infecções por Bacillaceae/diagnóstico , Evolução Fatal , Proteínas Hemolisinas/sangue , Humanos , Recém-Nascido , Doenças do Prematuro/diagnóstico , Masculino , Infecções Oportunistas/diagnóstico , Fosfolipases/sangue , Valores de ReferênciaRESUMO
We used the Bacillus brevis-pNU212 system to develop a mass production system for the protective antigen (PA) of Bacillus anthracis. A moderately efficient expression-secretion system for PA was constructed by fusing the PA gene from B. anthracis with the B. brevis cell-wall protein signal-peptide encoding region of pNU212, and by introducing the recombinant plasmid, pNU212-mPA, into B. brevis 47-5Q. The clone producing PA secreted about 300 microg of recombinant PA (rPA) per ml of 5PY-erythromycin medium after 4 days incubation at 30 degrees C. The rPA was fractionated from the culture supernatant of B. brevis 47-5Q carrying pNU212-mPA using ammonium sulfate at 70% saturation followed by anion exchange chromatography on a Hitrap Q, a Hiload 16/60 Superdex 200 gel filtration column and a phenyl sepharose hydrophobic interaction column, yielding 70 mg rPA per liter of culture. The N-terminal sequence of the purified rPA was identical to that of native PA from B. anthracis. The purified rPA exhibited cytotoxicity towards J774A.1 cells when combined with lethal factor. The rPA formulated in either Rehydragel HPA or MPL-TDM-CWS adjuvant (Ribi-Trimix) elicited the expression of a large amount of anti-PA and neutralizing antibodies in guinea pigs and completely protected them against a 100 LD50 challenge with fully virulent B. anthracis spores.
Assuntos
Antígenos de Bactérias/genética , Bacillus anthracis/genética , Bacillus anthracis/imunologia , Bacillus/genética , Bacillus/imunologia , Toxinas Bacterianas/genética , Sequência de Aminoácidos , Animais , Anticorpos Antibacterianos/biossíntese , Antígenos de Bactérias/biossíntese , Antígenos de Bactérias/isolamento & purificação , Antígenos de Bactérias/toxicidade , Infecções por Bacillaceae/imunologia , Infecções por Bacillaceae/prevenção & controle , Toxinas Bacterianas/biossíntese , Toxinas Bacterianas/isolamento & purificação , Toxinas Bacterianas/toxicidade , Sequência de Bases , Linhagem Celular , Clonagem Molecular , DNA Bacteriano/genética , Feminino , Expressão Gênica , Genes Bacterianos , Cobaias , Técnicas In Vitro , Camundongos , Testes de Neutralização , Plasmídeos/genética , Sinais Direcionadores de Proteínas/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/toxicidade , Esporos Bacterianos/genética , Esporos Bacterianos/imunologia , VirulênciaRESUMO
Reported here is a case of Bacillus cereus pneumonia that occurred in a patient with acute lymphoblastic leukemia. The presentation was severe, essentially marked by respiratory distress and pleuritic chest pain. Classic empirical treatment initiated for febrile neutropenia did not cover this rare pathogen and appropriate therapy was therefore delayed. B. cereus is most often a culture contaminant, but it can also be responsible for self-limited gastrointestinal intoxication and, more rarely, severe systemic diseases. Virulence in the case of systemic disease is attributed to tissue necrosis mediated by toxin release. B. cereus pneumonia, as described in the English-language literature, mainly affects immunocompromised patients and most often has a fatal outcome. Thus, the identification of B. cereus in clinical specimens of severely ill immunocompromised patients should lead physicians to question its clinical significance.
Assuntos
Infecções por Bacillaceae/diagnóstico , Infecções por Bacillaceae/imunologia , Bacillus cereus/isolamento & purificação , Hospedeiro Imunocomprometido , Pneumonia Bacteriana/microbiologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/complicações , Adulto , Antibacterianos , Infecções por Bacillaceae/tratamento farmacológico , Progressão da Doença , Quimioterapia Combinada/uso terapêutico , Evolução Fatal , Feminino , Humanos , Insuficiência de Múltiplos Órgãos/diagnóstico , Pneumonia Bacteriana/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/imunologia , Índice de Gravidade de DoençaRESUMO
We present a case of Bacillus cereus bacteremia and catheter infection in an immunocompetent patient subjected to abdominal surgery, who recovered following central catheter removal and treatment with piperacillin/tazobactam.
Assuntos
Infecções por Bacillaceae/microbiologia , Bacillus cereus/isolamento & purificação , Bacteriemia/microbiologia , Cateteres de Demora/microbiologia , Infecção Hospitalar/microbiologia , Procedimentos Cirúrgicos do Sistema Digestório/efeitos adversos , Ácido Penicilânico/análogos & derivados , Idoso , Infecções por Bacillaceae/tratamento farmacológico , Infecções por Bacillaceae/imunologia , Bacteriemia/tratamento farmacológico , Bacteriemia/imunologia , Cateterismo Venoso Central/efeitos adversos , Cateteres de Demora/efeitos adversos , Infecção Hospitalar/tratamento farmacológico , Quimioterapia Combinada , Humanos , Imunocompetência , Masculino , Ácido Penicilânico/uso terapêutico , Piperacilina/uso terapêutico , TazobactamRESUMO
In the zebrafish embryo, the only known site of hemopoieisis is an intra-embryonic blood island at the junction between trunk and tail that gives rise to erythroid cells. Using video-enhanced differential interference contrast microscopy, as well as in-situ hybridization for the expression of two new hemopoietic marker genes, draculin and leucocyte-specific plastin, we show that macrophages appear in the embryo at least as early as erythroid cells, but originate from ventro-lateral mesoderm situated at the other end of the embryo, just anterior to the cardiac field. These macrophage precursors migrate to the yolksac, and differentiate. From the yolksac, many invade the mesenchyme of the head, while others join the blood circulation. Apart from phagocytosing apoptotic corpses, these macrophages were observed to engulf and destroy large amounts of bacteria injected intravenously; the macrophages also sensed the presence of bacteria injected into body cavities that are isolated from the blood, migrated into these cavities and eradicated the microorganisms. Moreover, we observed that although only a fraction of the macrophage population goes to the site of infection, the entire population acquires an activated behaviour, similar to that of activated macrophages in mammals. Our results support the notion that in vertebrate embryos, macrophages endowed with proliferative capacity arise early from the hemopoietic lineage through a non-classical, rapid differentiation pathway, which bypasses the monocytic series that is well-documented in adult hemopoietic organs.
Assuntos
Macrófagos/citologia , Peixe-Zebra/embriologia , Animais , Infecções por Bacillaceae/imunologia , Bacillus subtilis/imunologia , Diferenciação Celular , Escherichia coli/imunologia , Infecções por Escherichia coli/imunologia , Gástrula/citologia , Regulação da Expressão Gênica no Desenvolvimento , Marcadores Genéticos , Hematopoese/genética , Células-Tronco Hematopoéticas/citologia , Hibridização In Situ , Ativação de Macrófagos , Macrófagos/imunologia , Glicoproteínas de Membrana , Mesoderma/citologia , Proteínas dos Microfilamentos , Microscopia de Vídeo , Fosfoproteínas/genética , Saco Vitelino/embriologia , Peixe-Zebra/genética , Peixe-Zebra/imunologiaRESUMO
We describe a case of rapidly progressive necrotizing cellulitis in an immunocompromised farmer caused by Bacillus cereus, and review 15 additional cases of serious soft tissue infection due to this organism reported in the English language literature. These cases illustrate the potential for B. cereus to cause fulminant soft tissue disease indistinguishable from that caused by clostridia.
Assuntos
Infecções por Bacillaceae/diagnóstico , Bacillus cereus/isolamento & purificação , Celulite (Flegmão)/microbiologia , Infecções por Clostridium/diagnóstico , Infecções por Bacillaceae/imunologia , Celulite (Flegmão)/imunologia , Infecções por Clostridium/imunologia , Diagnóstico Diferencial , Humanos , Hospedeiro Imunocomprometido , Masculino , Pessoa de Meia-Idade , Necrose , Infecções dos Tecidos Moles/imunologia , Infecções dos Tecidos Moles/microbiologiaRESUMO
An in vitro model of Bacillus piliformis infection was developed to investigate the mechanisms of adhesion and internalization of this obligate intracellular bacterium. Adhesion and internalization events were examined by electron microscopic evaluation of infected Caco-2 cell monolayers. A few bacteria were identified in apical surface invaginations and in vacuoles subjacent to the apical surface, whereas the majority of bacteria were observed free within the cytoplasm, suggesting that B. piliformis entered epithelial cells via a phagocytic process and rapidly escaped the phagosome. To confirm that host cell phagocytosis was involved in entry of B. piliformis into mammalian cells, Intestine 407 cells were treated with the phagocytic inhibitor cytochalasin D, infected with B. piliformis, and evaluated for bacterial internalization by double-fluorescence labeling. The results showed decreased intracellular bacteria, suggesting that internalization was dependent on host cell microfilament function. To examine the role of B. piliformis in internalization, growth of live and Formalin-killed bacteria was compared. Dead bacteria were not internalized, suggesting that B. piliformis actively participates in internalization. B. piliformis appears to enter host cells by a bacterially directed phagocytic process. The in vitro system described should prove invaluable in further investigations of B. piliformis pathogenic mechanisms.