TY - JOUR T1 - Nasal microbiota in RSV microbiota JF - European Respiratory Journal JO - Eur Respir J DO - 10.1183/13993003.congress-2019.PA4994 VL - 54 IS - suppl 63 SP - PA4994 AU - Sabrina Persia AU - Antonella Frassanito AU - Raffaella Nenna AU - Laura Petrarca AU - Greta Di Mattia AU - Antonella Merola AU - Valerio Iebba AU - Serena Schippa AU - Carolina Scagnolari AU - Alessandra Pierangeli AU - Fabio Midulla Y1 - 2019/09/28 UR - http://erj.ersjournals.com/content/54/suppl_63/PA4994.abstract N2 - Background: Respiratory Syncytial Virus (RSV) is the leading cause of bronchiolitis. The local bacterial ecosystem may influence RSV disease severity and the immune response.Aim: To evaluate the association between RSV infection, nasal microbiota composition (NMC) and patients’ immune response in infants with bronchiolitis.Materials and Methods: We characterized the NMC of 47 hospitalized infants <6 months with bronchiolitis from RSV (30 RSV-A and 17 RSV-B) and 29 non RSV. We evaluated biodiversity using the major ecological index and performed a partial least squares-discriminant and PCoA analysis. Linear discriminant analysis effect size algorithm was applied to determine discriminant bacterial species. In RSV-positive nasal samples, expression of several IFN type I/III related-genes were determined by quantitative RT-PCR. Moreover, the pattern of T-cell immune response was evaluated by intracellular staining of whole blood cultures.Results: NMC differed among RSV and non RSV groups. In RSV-positive nasal samples alfa-diversity was reduced and NMC differed between RSV-A and RSV-B. Discriminant bacterial species were Clostridium indolis for RSV-A group and Hemophilus haemolyticus for RSV-B. In infants with RSV, there was a significant cross-correlation among NMC (evaluated as β diversity) and white blood cells level, expression of Lambda3 and Beta IFN genes and Th1/Th2 response.Conclusions: This preliminary study showed differences in the NMC in relation to the aetiological cause of bronchiolitis and the type of immune response, that are worthy of further examination in larger groups.FootnotesCite this article as: European Respiratory Journal 2019; 54: Suppl. 63, PA4994.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only). ER -