RESUMO
Respiratory syncytial virus (RSV) is a major cause of diseases of the respiratory tract in young children and babies, being mainly associated with bronchiolitis. RSV infection occurs primarily in pulmonary epithelial cells and, once infection is established, an immune response is triggered and neutrophils are recruited. In this study, we investigated the mechanisms underlying NET production induced by RSV. We show that RSV induced the classical ROS-dependent NETosis in human neutrophils and that RSV was trapped in DNA lattices coated with NE and MPO. NETosis induction by RSV was dependent on signaling by PI3K/AKT, ERK and p38 MAPK and required histone citrullination by PAD-4. In addition, RIPK1, RIPK3 and MLKL were essential to RSV-induced NETosis. MLKL was also necessary to neutrophil necrosis triggered by the virus, likely promoting membrane-disrupting pores, leading to neutrophil lysis and NET extrusion. Finally, we found that RSV infection of alveolar epithelial cells or lung fibroblasts triggers NET-DNA release by neutrophils, indicating that neutrophils can identify RSV-infected cells and respond to them by releasing NETs. The identification of the mechanisms responsible to mediate RSV-induced NETosis may prove valuable to the design of new therapeutic approaches to treat the inflammatory consequences of RSV bronchiolitis in young children.
Assuntos
Armadilhas Extracelulares/metabolismo , Necrose/metabolismo , Neutrófilos/metabolismo , Desiminases de Arginina em Proteínas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Infecções por Vírus Respiratório Sincicial/metabolismo , Vírus Sincicial Respiratório Humano/patogenicidade , Adulto , Células Epiteliais Alveolares/metabolismo , Células Epiteliais Alveolares/virologia , Animais , Apoptose/fisiologia , Bronquiolite/metabolismo , Bronquiolite/virologia , Linhagem Celular , Chlorocebus aethiops , Armadilhas Extracelulares/virologia , Feminino , Humanos , Pulmão/metabolismo , Pulmão/virologia , Masculino , Necrose/virologia , Neutrófilos/virologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteína-Arginina Desiminase do Tipo 4 , Infecções por Vírus Respiratório Sincicial/virologia , Transdução de Sinais/fisiologia , Células VeroAssuntos
Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/crescimento & desenvolvimento , Antibacterianos/farmacologia , Meropeném/farmacologia , Polimixina B/farmacologia , Acinetobacter baumannii/isolamento & purificação , Doença Crônica , Contagem de Colônia Microbiana , Farmacorresistência Bacteriana , Sinergismo Farmacológico , Humanos , Testes de Sensibilidade Microbiana , Viabilidade MicrobianaRESUMO
Stenotrophomonas maltophilia is an emerging nosocomial pathogen responsible for several infections in immunocompromised patients. To characterize the antimicrobial resistance and virulence potential of this microorganism in a Brazilian hospital, a total of 936 samples were collected from a nosocomial environment and medical devices, and 100 isolates from clinical specimens were obtained in the same hospital. S. maltophilia was found in 3% of the samples collected, especially in bed rails from hospital rooms. The smf-1 gene was detected in 23% and 42% of the clinical and hospital environment isolates, respectively, and almost all (96.8%) isolates that harbored smf-1 were able to form biofilm. All isolates were susceptible to minocycline and chloramphenicol, and the majority of isolates were susceptible to levofloxacin. High resistance to ceftazidime was detected in both groups of isolates. Resistance to trimethoprim-sulfamethoxazole (TMP/SMX) was found in 14.8% of the isolates. All TMP/SMX-resistant isolates presented class 1 integron and sul1 gene, and 47.4% of them also harbored the sul2 gene, which was inserted into a 7.3 kb plasmid. Genetic relatedness among the isolates was evaluated by enterobacterial repetitive intergenic consensus-PCR, and eight genetic patterns were identified. One pattern comprised 54.7% of isolates and was spread among clinical and environmental (furniture and medical devices) sources. The presence of S. maltophilia in the hospital environment indicates that it can act as a reservoir of this microorganism. In addition, hospital isolates resistant to TMP/SMX showed that the genetic determinants were present in mobile elements, which can constitute great concern, as it may indicate a tendency to spread.