Genetic clustering of human rhinovirus strains in infants with severe bronchiolitis
Session III – Paranhos-Baccala, Glaucia, Abstract 2 of 2
Title of Contribution: Genetic clustering of human rhinovirus strains in infants with severe bronchiolitis
Author(s): Florence Komurian-Pradel1, Jean-Noel Telles1, Bertrand Bonnaud2; Magali Perret1, Alain Rajoharison1, Nathalie Richard3, Daniel Floret3, Guy Vernet1, Bruno Lina 4, Gláucia Paranhos-Baccalà1
Affiliation(s): 1Emerging Pathogens Laboratory, Fondation Mérieux, IFR128 BioSciences Lyon-Gerland, Lyon-France, 2Knowledge engineering Department, bioMérieux, Marcy l’Etoile-France,3 Service d’Urgences et de Réanimation Pédiatriques, HFME, Bron-France, 4 Laboratoire de Virologie, HFME, Bron-France
Abstract:
Human rhinoviruses (HRV) cause a wide spectrum of clinical outcomes, and are more and more reported in and related to acute lower respiratory infections such as bronchiolitis. The diversity of rhinoviruses is represented by the presence of 101 distinct antigenic entities designated as serotypes. But little is known about the circulation and the relative impact of each HRV serotypes and their potential differences in term of pathogenicity. The aim of our study is to characterize rhinoviruses at the molecular level, to explore the presence and the role of genetically distinct HRVs in infants suffering from bronchiolitis, hospitalized either in a short-term unit or in a pediatric intensive care unit (PICU) according to their bronchiolitis severity. For this purpose, 180 infants aged less than 12 months, were enrolled during two consecutive winter seasons 2003/2004 and 2004/2005. Molecular analysis were performed to detect respiratory viruses in nasal/throat swabs and nasal aspirates. HRV was found in 21.2 % of cases (39/180), and then represent the second viral agent identified, after RSV (Richard et al., PIDJ 2008; 27(3):213-217). 29 of these HRV positive specimen were available for further analysis. Phylogenetic analysis was performed on the VP4 region of HRV. The relationship between HRV characterized in this study and the most related HRV prototypes or published strains was investigated. The most divergent HRVs were found into HRV-C group. Indeed, whereas the maximum of diversity in nucleotide reach 11.2% for HRVs from two cases belonging to group A and B respectively, a diversity of up to 28.7% was observed inside HRVs from group C. To assay the clinical impact of HRV genotype, the distribution of HRV-A, -B and - C was compared among infants requiring or not intensive care support (PICU). Statistical analysis showed that there is no link (p = 0.078, Fisher exact test) between genotypes and bronchiolitis severity. 9 out of 16 HRVs belongs to group A, 3 out 3 HRVs from group B and 4 out of 10 HRVs from group C were detected in infants who had been admitted to PICU for supplemental oxygen requirement. Interestingly, HRVs from group B were observed only in samples obtained from patients hospitalized in PICU. The relationship between HRV genotypes and HRV dual viral infection was also investigated. Dual infection was found in 13 out 29 studied cases of HRV infection (62.5% in PICU, 23% in short term unit) and represents as previously described, a risk factor for admission in PICU. No relationship could be found between the genotypes and the presence of dual infection (p = 0.17, Fisher exact test).
