RESUMO
Olfactory ensheathing cells (OECs) are a type of specialized glial cell currently considered as having a double function in the nervous system: one regenerative, and another immune. Streptococcus pneumoniae is a major agent of severe infections in humans, including meningitis. It is commonly found in the nasopharynx of asymptomatic carriers, and, under certain still unknown conditions, can invade the brain. We evaluated whether pneumococcal cells recovered from lysed OECs and microglia are able to survive by manipulating the host cell activation. An intracellular-survival assay of S. pneumoniae in OECs showed a significant number of bacterial CFU recovered after 3 h of infection. In contrast, microglia assays resulted in a reduced number of CFU. Electron-microscopy analysis revealed a large number of pneumococci with apparently intact morphology. However, microglia cells showed endocytic vesicles containing only bacterial cell debris. Infection of OEC cultures resulted in continuous NF-κB activation. The IFN-γ-induced increase of iNOS expression was reversed in infected OECs. OECs are susceptible to S. pneumoniae infection, which can suppress their cytotoxic mechanisms in order to survive. We suggest that, in contrast to microglia, OECs might serve as safe targets for pneumococci, providing a more stable environment for evasion of the immune system.
Assuntos
Microglia/citologia , Bulbo Olfatório/citologia , Streptococcus pneumoniae/crescimento & desenvolvimento , Animais , Células Cultivadas , Contagem de Colônia Microbiana , Interferon gama/metabolismo , Microglia/metabolismo , Microglia/microbiologia , Microscopia Eletrônica , NF-kappa B/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Bulbo Olfatório/metabolismo , Bulbo Olfatório/microbiologia , RatosRESUMO
Clostridium difficile is an important nosocomial enteric pathogen and is the etiological agent of pseudomembranous colites. Recently, the rates of C. difficile infection (CDI) have increased worldwide, but in Brazil few data about this situation and the incidence of clonal types of C. difficile exist. This study aimed to isolate and characterize C. difficile strains from samples obtained of a university hospital (HUCFF) in Rio de Janeiro city, Brazil. CDI was identified by ELISA in 27.1% of HUCFF-in-patients enrolled in the study, and the bacterium was recovered from eight of these fecal samples. All strains, except one, presented tcdA and tcdB genes and presented neither the cdtA and cdtB genes nor any significant deletions in the tcdC gene. All strains were sensitive to metronidazole, vancomycin and moxifloxacin, and resistant to clindamycin, ciprofloxacin and levofloxacin. PCR-ribotyping and PFGE revealed four different clonal types among the isolates. The Brazilian PCR-ribotype 133 accounted for 50% of strains isolated, and PCR-ribotype 233 strains were obtained from 25% of the in-patients. The prevalence and resurgence of the Brazilian PCR-ribotype 133 among the hospitalized patients of HUCFF was established, and cross-infection of different patients associated to the same PCR-ribotypes was detected. Our results emphasize the importance of the diagnosis and control of CDI in order to prevent the emergence of specific clones that can lead to C. difficile-associated outbreaks in Brazilian hospitals.
Assuntos
Técnicas de Tipagem Bacteriana , Clostridioides difficile/classificação , Clostridioides difficile/isolamento & purificação , Infecções por Clostridium/epidemiologia , Infecção Hospitalar/epidemiologia , Ribotipagem , Adulto , Idoso , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Brasil/epidemiologia , Clostridioides difficile/genética , Infecções por Clostridium/microbiologia , Análise por Conglomerados , Infecção Hospitalar/microbiologia , Impressões Digitais de DNA , Farmacorresistência Bacteriana , Eletroforese em Gel de Campo Pulsado , Enterotoxinas/genética , Feminino , Genótipo , Hospitais Universitários , Humanos , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Ribotipagem/métodosRESUMO
The presence of enterotoxigenic Bacteroides fragilis and nontoxigenic B. fragilis (NTBF) among 109 strains isolated from 1980-2008 in Brazil were investigated by PCR. One strain, representing 0.9% of the total analyzed strains, harbored the bft gene which was identified as bft-1 isoform based on PCR-RFLP and sequencing. Forty-nine strains (44.9%) exhibited the NTBF pattern III which possesses the flanking region required for pathogenicity island acquisition in which the bft gene is codified. These data reinforce the potential of B. fragilis as an emerging enteropathogen in our country.
Assuntos
Bacteroides fragilis/genética , Enterotoxinas/biossíntese , Genes Bacterianos/genética , Bacteroides fragilis/classificação , Bacteroides fragilis/patogenicidade , Brasil , Humanos , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de RestriçãoRESUMO
The presence of enterotoxigenic Bacteroides fragilis and nontoxigenic B. fragilis (NTBF) among 109 strains isolated from 1980-2008 in Brazil were investigated by PCR. One strain, representing 0.9 percent of the total analyzed strains, harbored the bft gene which was identified as bft-1 isoform based on PCR-RFLP and sequencing. Forty-nine strains (44.9 percent) exhibited the NTBF pattern III which possesses the flanking region required for pathogenicity island acquisition in which the bftgene is codified. These data reinforce the potential of B. fragilis as an emerging enteropathogen in our country.
