Molecular epidemiology and molecular characterization of respiratory syncytial viruses at a tertiary care university hospital in Catalonia (Spain) during the 2013-2014 season.

BACKGROUND

Human respiratory syncytial virus (HRSV) is the main cause of lower respiratory tract infections among infants and young children.

OBJECTIVES

The molecular epidemiology and characterization of HRSV strains detected at a Spanish tertiary hospital during the 2013-2014 season is reported.

STUDY DESIGN

Phylogenetic analysis and molecular characterization of HRSV laboratory-confirmed respiratory samples were performed, based on coding sequences of G and F proteins.

RESULTS

HRSV infection was laboratory-confirmed in respiratory samples from 320 patients of which 223 (70%) were less than 2 years of age and none undergoing Palivizumab treatment. HRSV was detected at varying levels throughout the season with a maximum rate in the week 52/2013, right before the beginning of the influenza epidemic. Whilst both HRSV groups were found co-circulating, HRSV-B group clearly predominated. The phylogenetic analyses from 139 HVR-2 sequences revealed that most characterized strains belonged to ON1 and BA9 genotypes. Three different phylogenetic subgroups could be distinguished within these genotypes. In addition, three strains (out of the 52 randomly selected) were carrying amino acid substitutions in the epitope A of the F protein, one of them previously related to Palivizumab resistance.

CONCLUSIONS

The results of the present study highlight the importance of a continuous HRSV surveillance to monitor not only the introduction of new genotypes on circulation but also the emergence of viral variants with new genetic characteristics that can affect the antigenicity features and the susceptibility to the only current prophylaxis treatment and also for the future development of HRSV vaccines.