Characteristics of Staphylococcus aureus biofilm producer isolates capable of nasal colonization.

BARBAGELATA, MS; DOTTO, CM; GRUNERT, T; SORDELLI, DO; EHLING-SCHULZ, M; BUZZOLA FR

Conferencia; International Conference on Microbial Biofilms; 2014

Introduction: The nasal vestibule is the most frequent carriage location by Staphylococcus aureus and this is a risk factor for infection in hospitalized patients. More than 50% of the healthy adult population shows persistent or intermittent nasal colonization by S. aureus. The remaining individuals are rarely or never colonized by this pathogen. S. aureus is the causative agent of a diverse array of acute and chronic infections owing to its ability to attach to a surface and form a biofilm. The polysaccharide intercellular adhesin (PIA) encoded by the icaADBC operon play an important role in staphylococcal biofilms matrix production. Obj: The aim of the present study was analyse the biofilm production of S. aureus nasal isolates typed by molecular and phenotypic methods. Results: S. aureus isolates were collected from nasal swabs based on the standard prophylactic procedure at admission to two hospitals in Argentina. Of the 258 individuals screened, 62 (24%) tested positive for S. aureus nasal colonization. Forty-one isolates were registered as slime-positive by Congo red agar plates. In vitro quantification of biofilm production permitted to classify 19 and 15 isolates as high (HP) and moderate (MP) biofilm producers, respectively. The 28 isolates resting showed be weak or non-producer (NP) of biofilm. Treatment with proteinase K virtually disrupted preformed biofilms for the total of isolates. Whereas treatment with DNAse I did not affect biofilm detachment of 38% of the isolates. The quantity of PIA production was determined by ELISA method. Only four nasal isolates classified as HP and MP produced significantly (p