Biofilm formation of Streptococcus pneumoniae from bronchial alveolar lavage and from nasal swab

Abstract

Introduction. Infection induced by Streptococcus pneumoniae concerns mainly children, the elderly, and people suffering from chronic diseases. The number of deaths caused by pneumococcus infections is rising worryingly. The ability to create biofilm is the main virulence factor for S. pneumoniae . The aim of this study was to evaluate the ability to form biofilm (using two different dyes) of the bacterial strains isolated from nasal and BAL, and evaluate the relationship between antibiotic sensitivity and production of biofilm. Materials and methods. For the study of S. pneumoniae biofilm formation in 96-well microtitre plates, crystal violet (CV) and tetrazolium dyes — 2,3,5-triphenyl-tetrazolium chloride (TTC) were used. Results. All isolates were able to form some degree of biofilm. The results obtained by the two methods were not significantly correlated when comparing the biofilm mass. The strains produced biofilm mass intensive when the dye was CV — 29 (96.6%) strains of S. pneumoniae strong biofilm production. When the dye was TTC, it was observed that 14 (46.6%) strains of S. pneumoniae formed strong biofilm. Conclusions. There was no significant relationship between the ability of S. pneumoniae to form biofilms and the source of isolates.