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No description available.

Background: Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infection and hospitalization in children worldwide. With no vaccine or antivirals available for the routine prevention or treatment of RSV, an effective RSV antiviral is required. Previous studies have shown that the RSV nucleocapsid complex (NC), phosphoprotein (P), and large polymerase (L) are essential for the replication and survival of RSV since they form the core of the RNA-dependent RNA polymerase (RdRp) complex. Thus, these proteins are viable targets for novel RSV antivirals. Objective: The Mahony laboratory has previously shown that 20 µM of a peptide mimetic composed of the 21 terminal amino acids of the RSV phosphoprotein (RSVP220-241) fused to an HIV-1 Tat cell penetrating peptide (CPP), a hexa-histidine (His) tag, and the Escherichia coli (E. coli) maltose binding protein carrier (MBP) molecule was sufficient to attenuate RSV A and B replication in vitro by approximately 90 and 80%, respectively. We evaluated the fusion of this His-MBP-Tat-RSVP220-241 mimetic to a more suitable carrier molecule, an albumin-binding domain (ABD), for future use in vivo. In addition, we designed a novel antiviral mimetic composed of the 30 terminal amino acids of the RSV A P protein (RSVP212-241), which are involved in binding both L polymerase and NC complexes, fused to a CPP consisting of Tat or nine arginine residues (Arg9), a His-tag, and the MBP carrier. We evaluated the activity of His-MBP-Tat-RSVP212-241, Tat-His-MBP-Tat-RSVP212-241, and His-Arg9-MBP-RSVP212-241 mimetics in vitro and hypothesized that a mimetic designed to target both L and NC interactions would be a more effective RSV antiviral than the original His-MBP-Tat-RSVP220-241 mimetic. Methods and Results: The Gateway® Cloning System was used to create expression vectors containing His-, GST-, or His-MBP-ABD-Tat-RSVP220-241 and His-MBP-Tat-RSVP212-241, whereas inverse PCR and both the In-Fusion® and Gateway® Cloning systems were used to generate expression vectors containing Tat-His-MBP-Tat-RSVP212-241 and His-Arg9-MBP-RSVP212-241. The fusion proteins were expressed, purified by affinity chromatography, and evaluated in vitro. No soluble protein was obtained for the ABD constructs. His-MBP-Tat-RSVP212-241 was toxic and not internalized by LLC-MK2 cells, whereas only 0.26 mg of Tat-His-MBP-Tat-RSVP212-241 was purified. We were able to show that His-Arg9-MBP-RSVP212-241 was non-toxic, internalized, and interacted with the RSV nucleoprotein (N) in a GST pull-down experiment. Furthermore, His-Arg9-MBP-RSVP212-241 attenuated RSV A replication and progeny production by 94.8 and 93.33% at 200 µM, respectively. We demonstrated 50.7 and 49% inhibition of RSV A replication and progeny production at 20 µM, respectively. We showed that inhibition of viral replication by 25 µM His-Arg9-MBP-RSVP212-241 was not significantly different from inhibition by 20 µM His-MBP-Tat-RSVP220-241. Thus, in this thesis we were unable to show that His-Arg9-MBP-RSVP212-241 was a more effective RSV antiviral. Conclusion: The ABD was not a suitable carrier molecule for use with our fusion protein mimetics. However, RSV P protein mimetics that target interactions with the NC complexes and L polymerase are a novel and viable antiviral strategy. We showed that a His-Arg9-MBP-RSVP212-241 mimetic was non-toxic, internalized, and interacted with the RSV N protein in vitro. Furthermore, we showed that at 200 µM this novel mimetic could attenuate RSV A replication and progeny production in vitro by 94.8 and 93.3%, respectively. Further studies are required to characterize the construct, increase its bioactivity, and identify a suitable human carrier molecule for future evaluation in vivo. / Thesis / Master of Science (MSc) / Worldwide, respiratory syncytial virus is a leading cause of lower respiratory infection and hospitalization in children. Nearly all children are infected with the virus by the young age of two. However, respiratory syncytial virus also causes a significant amount of illness and death in the elderly and in immunocompromised individuals. Furthermore, repeated infections by the virus are common throughout life in all populations. With the lack of a vaccine or treatment for this viral infection, an effective antiviral against RSV is required. In this thesis, we developed and evaluated a novel RSV antiviral therapeutic peptide that targets proteins of the viral replication machinery. Since the replication machinery is required for respiratory syncytial virus survival, we hypothesized that infection could be attenuated by preventing formation of the replication machinery. Furthermore, since small protein therapeutics are often cleared quickly from the human body, we investigated human carrier molecules that could be attached to the antiviral protein for stabilization within the body.

Respiratory syncytial virus (RSV) causes a common infection that is associated with a range of respiratory illnesses from common cold-like symptoms to serious lower respiratory tract illnesses such as pneumonia and bronchiolitis. RSV is the single most important cause of serious lower respiratory tract illness in children < 1 year of age. Host innate and acquired immune responses activated following RSV infection have been suspected as contributing to RSV disease. Toll-like receptors (TLRs) activate innate and acquired immunity and are candidates for playing key roles in the host immune response to RSV. Leukocytes express TLRs including TLR2, TLR6, TLR3, TLR4, and TLR7 that can potentially interact with RSV and promote immune responses following infection. Using knockout mice, we have demonstrated that TLR2 and TLR6 signaling in leukocytes can activate innate immunity against RSV by promoting TNF-α, IL-6, CCL2 (MCP-1), and CCL5 (RANTES) production. As previously noted, TLR4 also contributed to cytokine activation (71, 90). Furthermore, we demonstrated that signals generated following TLR2 and TLR6 activation were important for controlling viral replication in vivo. Additionally, TLR2 interactions with RSV promoted neutrophil migration and dendritic cell activation within the lung. Collectively, these studies indicate that TLR2 is involved in RSV recognition and subsequent innate immune activation and may play a role in modulating acquired immune responses through DCs. Despite the fact that RSV is the single most important cause of infant upper respiratory tract disease, there are no licensed vaccines available to prevent RSV disease. We have developed a virus-like particle (VLP) vaccine candidate for RSV. The VLP is composed of the NP and M proteins of Newcastle disease virus (NDV) and a chimera protein containing the cytoplasmic and transmembrane domains of the NDV HN protein and the ectodomain of the human RSV G protein (H/G). BALB/c mice immunized with 10 or 40 μg total VLP-H/G protein by intraperitoneal or intramuscular inoculation stimulated antibody responses to G protein as good as or better than comparable amounts of UV-inactivated RSV. Furthermore, VLP-H/G induced robust CTL responses in vaccinated animals. Immunization with two or even a single dose of these particles resulted in the complete protection of BALB/c mice from RSV replication in the lungs. Upon RSV challenge of VLP-H/G immunized mice, no enhanced pathology in the lungs was observed, although lungs of mice immunized in parallel with formalin-inactivated RSV (FI-RSV) showed the significant pathology that has been previously observed with FI-RSV vaccination. Thus, the VLP-H/G candidate vaccine was immunogenic in BALB/c mice and prevented replication of RSV in murine lungs with no evidence of immunopathology. These data support further development of virus-like particle vaccine candidates for RSV.

Introdução: A bronquiolite aguda é a principal causa de internação de lactentes menores de um ano de idade e tem como principal agente etiológico o vírus sincicial respiratório. As principais diretrizes baseadas em evidências recomendam o tratamento de suporte com hidratação e oxigenoterapia, quando necessário e não indicam o uso rotineiro de corticosteroides, broncodilatadores e antibióticos. No entanto, estudos anteriores mostraram que o uso inadvertido dessas medicações é frequente na prática clínica. Objetivo: Analisar o tratamento aplicado a lactentes com bronquiolite viral aguda em um hospital público e compará-lo a diretrizes nacionais e internacionais. Casuística e métodos: Foi realizado um estudo observacional, transversal, descritivo e analítico que incluiu crianças menores de 2 anos, internadas no Hospital do Servidor Público Estadual durante dois anos (2012 - 2014), com primeiro episódio de sibilância e que tiveram coletado aspirado de nasofaringe, para pesquisa de vírus sincicial respiratório na admissão. Foram excluídos os lactentes com fatores de risco conhecidos para desenvolver doença grave. As informações foram coletadas dos prontuários e por contato telefônico com os responsáveis. Resultados: Dentre os 129 pacientes com resultado positivo para a pesquisa do vírus sincicial respiratório, 7 foram excluídos por apresentarem alguma comorbidade ou fator de risco prognóstico e 2 não tiveram o seus prontuários encontrados. A idade média, dos 120 estudados, foi de 6,8 meses e 51,6% foram do sexo feminino. Broncodilatadores, corticosteroides, antibióticos e inalação com solução salina hipertônica foram prescritos, durante a internação, a 90%, 72,5%, 40% e 66,7% dos casos, respectivamente. O uso dessas medicações foi excessivo e não compatível com as diretrizes, exceto o uso de solução salina hipertônica inalatória que esteve em acordo com a recomendação da Sociedade Brasileira de Pediatria. Após ajuste para confundidores, a chance de prescrição de antibióticos foi menor em menores de 3 meses (OR=0,21, p= 0,007) e também associada à presença de febre na admissão (OR=3, p = 0,013) e maior tempo de internação (OR=2,53, p= 0,003). A introdução de oxigênio suplementar apresentou associação com maior tempo de internação (OR=12,9, p < 0,001). Os lactentes com idade abaixo de 3 meses tiveram menor chance de prescrição de corticosteroides (OR=0,67, p < 0,001) que também foi associada à saturação menor que 95% no momento da admissão (OR=3,17, p= 0,037) e ao maior tempo de internação. O uso de solução salina hipertônica também foi associado ao maior tempo de internação (OR=3,07, p < 0,001). Conclusão: Em lactentes hospitalizados em um hospital público, o uso de antibióticos, corticosteroides e broncodilatadores para tratamento da bronquiolite aguda foi elevado. Essas condutas não seguiram as recomendações das principais diretrizes nacionais e internacionais. O uso de solução salina hipertônica inalatória seguiu a diretriz da Sociedade Brasileira de Pediatria / Background: Acute bronchiolitis is the main cause of hospitalization of infants under one year of age and has respiratory syncytial virus as the main etiological agent. The main evidence-based guidelines recommend hydration and oxygen therapy support when necessary and do not indicate the routine use of corticosteroids, bronchodilators and antibiotics. However, previous studies have shown that inadvertent use of these medications is common in clinical practice. Objective: To analyze the treatment of infants with acute viral bronchiolitis in a public hospital and to compare it with national and international guidelines. Patients and methods: An observational, transversal, descriptive and analytical study was carried out, including children under 2 years of age, hospitalized between two years (2012 - 2014), with first episode of wheezing and nasopharyngeal test for respiratory syncytial virus on admission. Infants with known risk factors for developing severe disease were excluded. The information was collected from the medical records and by telephone contact with those parents. Result: Of the 129 patients with a positive test for respiratory syncytial virus, 7 were excluded because they presented some comorbidity or a prognostic risk factor, and 2 did not have their charts found. The mean age of the 120 studied was 6.8 months and 51.6% were female. Bronchodilators, corticosteroids, antibiotics and nebulised hypertonic saline were prescribed, during hospitalization, at 90%, 72.5%, 40% and 66.7% of the cases, respectively. The use of these medications was excessive and not compatible with the guidelines, except the use of nebulised hypertonic saline that was in agreement with the recommendation of the Brazilian Society of Pediatrics. After adjusting for confounders, the chance of antibiotic prescription was lower in children younger than 3 months (OR = 0.21, p = 0.007) and also associated with the presence of fever at admission (OR = 3, p = 0.013) and a longer stay (OR = 2.53, p = 0.003). The introduction of supplemental oxygen showed an association with longer hospitalization (OR = 12.9, p < 0.001). Infants less than 3 months of age had a lower chance of prescribing corticosteroids (OR = 0.67, p < 0.001), which was also associated with a saturation of less than 95% on admission (OR = 3.17, p = 0.037 ) and longer hospitalization time. The use of nebulised hypertonic saline was also associated with longer length of stay (OR = 3.07, p < 0.001). Conclusion: In infants hospitalized in a public hospital, the use of antibiotics, corticosteroids and bronchodilators to treat acute bronchiolitis was high. These conducts did not follow the recommendations of the main national and international guidelines. The use of nebulised hypertonic saline followed the guideline of the Brazilian Society of Pediatrics

Introdução: A bronquiolite aguda é a principal causa de internação de lactentes menores de um ano de idade e tem como principal agente etiológico o vírus sincicial respiratório (VSR). O diagnóstico baseia-se na apresentação clínica e epidemiologia. A maioria das medidas terapêuticas é controversa e apesar da etiologia viral, a prescrição de antibióticos sistêmicos é freqüente. Não está claro se a pesquisa etiológica viral pode influenciar na conduta nesses lactentes. Objetivo: Analisar o impacto da realização de pesquisa etiológica viral sobre a conduta terapêutica, em lactentes internados com bronquiolite aguda. Casuística e métodos: Foi realizado estudo de coorte histórica que incluiu lactentes menores de 12 meses, internados no Hospital Universitário da USP durante dois anos, com diagnóstico de alta de bronquiolite aguda e que tiveram coletado aspirado de nasofaringe, para pesquisa viral, por imunofluorescência indireta (IFI), à admissão. Foram excluídos os lactentes com fatores de risco conhecidos para desenvolver doença grave. As informações foram coletadas dos prontuários. As alterações de condutas realizadas até 24 horas após a divulgação do diagnóstico etiológico foram consideradas associadas ao resultado da IFI. Resultados: Dentre 1199 lactentes, menores de 12 meses hospitalizados, 71% apresentaram diagnóstico de doença aguda do aparelho respiratório, sendo que 33% apresentaram bronquiolite. Desses, 33 foram excluídos e 20 não puderam ter a análise concluída. A idade média, dos 230 lactentes estudados, foi de 4 meses (± 2,7) e 56% foram do sexo masculino. Broncodilatadores, corticosteróides e antibióticos foram prescritos, à admissão em 80%, 52% e 55% dos casos, respectivamente. A pesquisa viral foi positiva para algum vírus em 165 casos e negativa em 65. O VSR foi identificado em 146 casos e outros vírus em 19. Os grupos com pesquisa viral negativa e positiva foram semelhantes com relação à prescrição de antibióticos (52% x 56%, respectivamente, p = 0,636), corticosteróide (42% x 56% -p = 0,052) e broncodilatadores (74% x 83%, p = 0,114) à admissão. A suspensão de antibióticos predominou nos pacientes com pesquisa viral positiva (35,6% x 9,2%, p < 0,001). Não houve alteração significante quanto as prescrições de corticosteróides e broncodilatadores. Também na comparação entre pacientes VSR (+) e com resultado negativo para pesquisa viral, o padrão de alterações de conduta foi semelhante. Houve suspensão de antibióticos em 32,2% e 9,2%, respectivamente (p < 0,001). O resultado positivo da pesquisa viral foi o único fator independentemente associado à suspensão de antibióticos, tanto no grupo com pesquisa viral positiva para qualquer vírus (RR = 3,37, p = 0,005) como no grupo VSR(+) (RR = 3,33, p = 0,006) Conclusão: Em lactentes hospitalizados com BA, o resultado positivo da pesquisa viral por IFI, foi determinante da suspensão de antibióticos sistêmicos, prescritos à admissão. / Background: Acute bronchiolitis is the leading cause of infant hospitalization, and it is most commonly caused by respiratory syncytial virus (RSV). Etiological tests are not required for its diagnosis, which can be made clinically. The most prescribed therapeutic measures are controversial, and in spite of the viral etiology, the prescription of systemic antibiotics is frequent. It remains unclear whether viral screening could contribute to therapy adjustment. Objective: To analyze the impact of viral screening on the therapeutic management of hospitalized infants with acute bronchiolitis. Patients and methods: A retrospective cohort was performed to assess the impact of RSV screening on medication prescription. The study included infants up to 1 year of age who were hospitalized at the University Hospital USP for 2 years, with bronchiolitis as discharge diagnosis and who had nasopharyngeal samples collected on admission for virus screening, by indirect immunofluorescence assay (IFA). Infants were excluded if they had a known risk factors for developing severe disease. Clinical information was obtained from the patients medical records. Therapeutic changes were considered to be associated with viral screening when made within 24 hours of the release of IFA results. Result: Among 1199 hospitalized infants younger than 12 months, 71% were diagnosed with acute lower respiratory disease, of which 33% had bronchiolitis. Of these, 33 were excluded and 20 could not have the analysis completed. The average age of the 230 infants studied was 4 months (+/- 2.7) and 56% were male. Bronchodilators, steroids and antibiotics were prescribed on admission for 80%, 52%, and 55% of cases, respectively. The viral test was positive for some virus in 165 cases and negative in 65. RSV was identified in 146 cases and other viruses in the 19. At admission, the groups with negative or positive viral test were similar regarding the prescription of antibiotics (52% vs 56% respectively, p=0.636), corticosteroids (42% vs 56%, p=0.052) and bronchodilators (74% vs 83%, p=0.114). The discontinuation of antibiotics predominated in patients who tested positive for virus (35.6% vs 9.2%, p<0.001). There were no significant changes regarding the prescription of corticosteroids and bronchodilators. Also, when comparing patients with viral test positive for RSV or negative for any virus the patterns were similar. There was discontinuation of antibiotics in 32.2 % and 9.2%, respectively (p=0.001). The positive result of viral test was the only independent factor associated with the discontinuation of antibiotics, both in the group with positive viral test for any virus (RR=3.37, p=0.005) and in the RVS (+) group (RR=3.33, p=0.006). Conclusion: In hospitalized infants with acute bronchiolitis, the positive result for virus screening, by IFA was an independent factor associated to the discontinuation of systemic antibiotics prescribed at admission.

Neste projeto caracterizamos a interação da nucleoproteína viral (N) do Vírus Respiratório Sincicial Humano (HRSV) com as proteínas PRMT5 e WDR77, que constituem o metilosomo celular. Confirmamos que essa interação ocorre através de co-imunoprecipitação em células humanas, e de interação in vitro dessas proteínas purificadas. Demonstramos a co-localização dessas proteínas na célula através de microscopias de imunofluorescência e confocal. Inibindo ou aumentando a expressão de PRMT5 não observamos impacto na replicação viral. Verificamos que ocorre metilação em N tanto em resíduos de argininas como de lisinas, com anticorpos específicos para essas modificações, e por espectrometria de massas, indicando significado funcional. Com essa evidência testamos o efeito de inibidores de metilação e demetilação, em argininas e lisinas. Obtivemos efeito inibitório significativo da replicação do HRSV com um inibidor de metilação de lisina, UNC0646, indicando que a interação N-metilossomo tem potencial como alvo terapêutico contra HRSV. / In this project we had as objective to characterize the interaction observed previously in the laboratory of viral nucleoprotein (N) with PRMT5 and WDR77 proteins that constitute the cell metilosome. We confirmed that this interaction occurs through co-imunoprecipitation in human cells and in vitro interaction of these purified proteins. We also demonstrated the co-localization of these proteins in inclusion bodies, by immunofluorescence and confocal microscopy. Inhibiting or enhancing PRMT5 expression we didnt see effect on viral replication. Our results show that methylation occurs in both arginine and lysine residues, through reactivity with antibodies specific to these modifications, and analysis by mass spectrometry. We tested the effect of arginine and lysine methylation and de-methylation inhibitors in viral replication. We obtained significant inhibitory effect on HRSV replication with a lysine methylation inhibitor, UNC0646, indicating that N-metilossome interaction has the potential to be exploited as a therapeutic target in developing antiviral drugs.

O Vírus Respiratório Sincicial Humano (HRSV) causa doença respiratória principalmente em recém-nascidos e bebês. A infecção por HRSV exerce forte interferência sobre a localização de actina, fenômeno que propomos estar relacionado à interação de TPM com M e P, levando ao rearranjo dos microtúbulos. Os objetivos gerais do projeto são de analisar interações in vitro, em bactéria e em célula entre TPM com M e P. Os dados obtidos indicam que ocorre a interação in vitro entre M e TPM 3 mas não ocorre entre P e TPM 3. Os estudos realizados em célula indicam a interação de M e P com TPM 3. Com siRNA para TPM 3 os dados não foram conclusivos e para a super expressão de TPM 3 verificamos que ocorre inibição da replicação viral. Testamos uma droga que desacopla TPM 3 dos filamentos de actina e os resultados indicam inibição da replicação viral. Concluímos com esses dados que TPM 3 tem papel fundamental no ciclo replicativo do vírus e que sua interação com M tem potencial para ser explorada como alvo terapêutico no desenvolvimento de antivirais contra HRSV. / Human Respiratory Syncytial Virus (HRSV) causes respiratory disease in newborns and babies. The HRSV infection exerts strong interference on intracellular location of actin, a phenomenon that we propose to be connected to the interaction of TPM with M and P, leading to the rearrangement of microtubules. In this project we propose to analyze interactions in vitro, in bacteria and in cells between TPM and P or M. The obtained data indicate that an in vitro interaction between M and TPM occurs but does not occur between P and TPM. Cell studies indicate an interaction of M and P with TPM. With siRNA fot TPM 3 the data were not conclusive, and for overexpression of TPM 3 an inhibition of virus replication was shown. Also, in cell, we obtained results indicating that the use of a cytoskeletal destabilizing drug is affecting viral replication. These data indicate that Tropomyosin plays a key role in the virus cycle and therefore has the potential to be exploited as a therapeutic target in the development of antiviral drugs against HRSV.

Introdução: A bronquiolite aguda é a principal causa de internação de lactentes menores de um ano de idade e tem como principal agente etiológico o vírus sincicial respiratório. As principais diretrizes baseadas em evidências recomendam o tratamento de suporte com hidratação e oxigenoterapia, quando necessário e não indicam o uso rotineiro de corticosteroides, broncodilatadores e antibióticos. No entanto, estudos anteriores mostraram que o uso inadvertido dessas medicações é frequente na prática clínica. Objetivo: Analisar o tratamento aplicado a lactentes com bronquiolite viral aguda em um hospital público e compará-lo a diretrizes nacionais e internacionais. Casuística e métodos: Foi realizado um estudo observacional, transversal, descritivo e analítico que incluiu crianças menores de 2 anos, internadas no Hospital do Servidor Público Estadual durante dois anos (2012 - 2014), com primeiro episódio de sibilância e que tiveram coletado aspirado de nasofaringe, para pesquisa de vírus sincicial respiratório na admissão. Foram excluídos os lactentes com fatores de risco conhecidos para desenvolver doença grave. As informações foram coletadas dos prontuários e por contato telefônico com os responsáveis. Resultados: Dentre os 129 pacientes com resultado positivo para a pesquisa do vírus sincicial respiratório, 7 foram excluídos por apresentarem alguma comorbidade ou fator de risco prognóstico e 2 não tiveram o seus prontuários encontrados. A idade média, dos 120 estudados, foi de 6,8 meses e 51,6% foram do sexo feminino. Broncodilatadores, corticosteroides, antibióticos e inalação com solução salina hipertônica foram prescritos, durante a internação, a 90%, 72,5%, 40% e 66,7% dos casos, respectivamente. O uso dessas medicações foi excessivo e não compatível com as diretrizes, exceto o uso de solução salina hipertônica inalatória que esteve em acordo com a recomendação da Sociedade Brasileira de Pediatria. Após ajuste para confundidores, a chance de prescrição de antibióticos foi menor em menores de 3 meses (OR=0,21, p= 0,007) e também associada à presença de febre na admissão (OR=3, p = 0,013) e maior tempo de internação (OR=2,53, p= 0,003). A introdução de oxigênio suplementar apresentou associação com maior tempo de internação (OR=12,9, p < 0,001). Os lactentes com idade abaixo de 3 meses tiveram menor chance de prescrição de corticosteroides (OR=0,67, p < 0,001) que também foi associada à saturação menor que 95% no momento da admissão (OR=3,17, p= 0,037) e ao maior tempo de internação. O uso de solução salina hipertônica também foi associado ao maior tempo de internação (OR=3,07, p < 0,001). Conclusão: Em lactentes hospitalizados em um hospital público, o uso de antibióticos, corticosteroides e broncodilatadores para tratamento da bronquiolite aguda foi elevado. Essas condutas não seguiram as recomendações das principais diretrizes nacionais e internacionais. O uso de solução salina hipertônica inalatória seguiu a diretriz da Sociedade Brasileira de Pediatria / Background: Acute bronchiolitis is the main cause of hospitalization of infants under one year of age and has respiratory syncytial virus as the main etiological agent. The main evidence-based guidelines recommend hydration and oxygen therapy support when necessary and do not indicate the routine use of corticosteroids, bronchodilators and antibiotics. However, previous studies have shown that inadvertent use of these medications is common in clinical practice. Objective: To analyze the treatment of infants with acute viral bronchiolitis in a public hospital and to compare it with national and international guidelines. Patients and methods: An observational, transversal, descriptive and analytical study was carried out, including children under 2 years of age, hospitalized between two years (2012 - 2014), with first episode of wheezing and nasopharyngeal test for respiratory syncytial virus on admission. Infants with known risk factors for developing severe disease were excluded. The information was collected from the medical records and by telephone contact with those parents. Result: Of the 129 patients with a positive test for respiratory syncytial virus, 7 were excluded because they presented some comorbidity or a prognostic risk factor, and 2 did not have their charts found. The mean age of the 120 studied was 6.8 months and 51.6% were female. Bronchodilators, corticosteroids, antibiotics and nebulised hypertonic saline were prescribed, during hospitalization, at 90%, 72.5%, 40% and 66.7% of the cases, respectively. The use of these medications was excessive and not compatible with the guidelines, except the use of nebulised hypertonic saline that was in agreement with the recommendation of the Brazilian Society of Pediatrics. After adjusting for confounders, the chance of antibiotic prescription was lower in children younger than 3 months (OR = 0.21, p = 0.007) and also associated with the presence of fever at admission (OR = 3, p = 0.013) and a longer stay (OR = 2.53, p = 0.003). The introduction of supplemental oxygen showed an association with longer hospitalization (OR = 12.9, p < 0.001). Infants less than 3 months of age had a lower chance of prescribing corticosteroids (OR = 0.67, p < 0.001), which was also associated with a saturation of less than 95% on admission (OR = 3.17, p = 0.037 ) and longer hospitalization time. The use of nebulised hypertonic saline was also associated with longer length of stay (OR = 3.07, p < 0.001). Conclusion: In infants hospitalized in a public hospital, the use of antibiotics, corticosteroids and bronchodilators to treat acute bronchiolitis was high. These conducts did not follow the recommendations of the main national and international guidelines. The use of nebulised hypertonic saline followed the guideline of the Brazilian Society of Pediatrics

Introdução: A bronquiolite aguda é a principal causa de internação de lactentes menores de um ano de idade e tem como principal agente etiológico o vírus sincicial respiratório (VSR). O diagnóstico baseia-se na apresentação clínica e epidemiologia. A maioria das medidas terapêuticas é controversa e apesar da etiologia viral, a prescrição de antibióticos sistêmicos é freqüente. Não está claro se a pesquisa etiológica viral pode influenciar na conduta nesses lactentes. Objetivo: Analisar o impacto da realização de pesquisa etiológica viral sobre a conduta terapêutica, em lactentes internados com bronquiolite aguda. Casuística e métodos: Foi realizado estudo de coorte histórica que incluiu lactentes menores de 12 meses, internados no Hospital Universitário da USP durante dois anos, com diagnóstico de alta de bronquiolite aguda e que tiveram coletado aspirado de nasofaringe, para pesquisa viral, por imunofluorescência indireta (IFI), à admissão. Foram excluídos os lactentes com fatores de risco conhecidos para desenvolver doença grave. As informações foram coletadas dos prontuários. As alterações de condutas realizadas até 24 horas após a divulgação do diagnóstico etiológico foram consideradas associadas ao resultado da IFI. Resultados: Dentre 1199 lactentes, menores de 12 meses hospitalizados, 71% apresentaram diagnóstico de doença aguda do aparelho respiratório, sendo que 33% apresentaram bronquiolite. Desses, 33 foram excluídos e 20 não puderam ter a análise concluída. A idade média, dos 230 lactentes estudados, foi de 4 meses (± 2,7) e 56% foram do sexo masculino. Broncodilatadores, corticosteróides e antibióticos foram prescritos, à admissão em 80%, 52% e 55% dos casos, respectivamente. A pesquisa viral foi positiva para algum vírus em 165 casos e negativa em 65. O VSR foi identificado em 146 casos e outros vírus em 19. Os grupos com pesquisa viral negativa e positiva foram semelhantes com relação à prescrição de antibióticos (52% x 56%, respectivamente, p = 0,636), corticosteróide (42% x 56% -p = 0,052) e broncodilatadores (74% x 83%, p = 0,114) à admissão. A suspensão de antibióticos predominou nos pacientes com pesquisa viral positiva (35,6% x 9,2%, p < 0,001). Não houve alteração significante quanto as prescrições de corticosteróides e broncodilatadores. Também na comparação entre pacientes VSR (+) e com resultado negativo para pesquisa viral, o padrão de alterações de conduta foi semelhante. Houve suspensão de antibióticos em 32,2% e 9,2%, respectivamente (p < 0,001). O resultado positivo da pesquisa viral foi o único fator independentemente associado à suspensão de antibióticos, tanto no grupo com pesquisa viral positiva para qualquer vírus (RR = 3,37, p = 0,005) como no grupo VSR(+) (RR = 3,33, p = 0,006) Conclusão: Em lactentes hospitalizados com BA, o resultado positivo da pesquisa viral por IFI, foi determinante da suspensão de antibióticos sistêmicos, prescritos à admissão. / Background: Acute bronchiolitis is the leading cause of infant hospitalization, and it is most commonly caused by respiratory syncytial virus (RSV). Etiological tests are not required for its diagnosis, which can be made clinically. The most prescribed therapeutic measures are controversial, and in spite of the viral etiology, the prescription of systemic antibiotics is frequent. It remains unclear whether viral screening could contribute to therapy adjustment. Objective: To analyze the impact of viral screening on the therapeutic management of hospitalized infants with acute bronchiolitis. Patients and methods: A retrospective cohort was performed to assess the impact of RSV screening on medication prescription. The study included infants up to 1 year of age who were hospitalized at the University Hospital USP for 2 years, with bronchiolitis as discharge diagnosis and who had nasopharyngeal samples collected on admission for virus screening, by indirect immunofluorescence assay (IFA). Infants were excluded if they had a known risk factors for developing severe disease. Clinical information was obtained from the patients medical records. Therapeutic changes were considered to be associated with viral screening when made within 24 hours of the release of IFA results. Result: Among 1199 hospitalized infants younger than 12 months, 71% were diagnosed with acute lower respiratory disease, of which 33% had bronchiolitis. Of these, 33 were excluded and 20 could not have the analysis completed. The average age of the 230 infants studied was 4 months (+/- 2.7) and 56% were male. Bronchodilators, steroids and antibiotics were prescribed on admission for 80%, 52%, and 55% of cases, respectively. The viral test was positive for some virus in 165 cases and negative in 65. RSV was identified in 146 cases and other viruses in the 19. At admission, the groups with negative or positive viral test were similar regarding the prescription of antibiotics (52% vs 56% respectively, p=0.636), corticosteroids (42% vs 56%, p=0.052) and bronchodilators (74% vs 83%, p=0.114). The discontinuation of antibiotics predominated in patients who tested positive for virus (35.6% vs 9.2%, p<0.001). There were no significant changes regarding the prescription of corticosteroids and bronchodilators. Also, when comparing patients with viral test positive for RSV or negative for any virus the patterns were similar. There was discontinuation of antibiotics in 32.2 % and 9.2%, respectively (p=0.001). The positive result of viral test was the only independent factor associated with the discontinuation of antibiotics, both in the group with positive viral test for any virus (RR=3.37, p=0.005) and in the RVS (+) group (RR=3.33, p=0.006). Conclusion: In hospitalized infants with acute bronchiolitis, the positive result for virus screening, by IFA was an independent factor associated to the discontinuation of systemic antibiotics prescribed at admission.