Fibronectin binding proteins in Staphylococcus aureus strains isolated from 6 to 14-year-old nasal carriers

Abstract number: R2085

Yapar N., Avkan-Oguz V.

Objective:Staphylococcus aureus is an important pathogen capable of causing a variety of infections. Nasal carriage rates for S. aureus have been reported to be between 18% and 50% in different populations and this carriage represents a risk factor for invasive infections. The aim of the study presented here was to investigate the presence of fibronectin binding proteins (FnBPs) mediating adhesion of S. aureus to human epithelial cells.

Methods: Fifty S. aureus strains isolated from nasal swab specimens of 6–14 years old healthy children were included in the study. Specimens were inoculated on mannitol salt agar plates and all colonies surrounded by yellow zones on plates after 24–48 hours of incubation at 37°C were selected. The isolates were identified by biochemical properties and tube coagulase test. Methicillin susceptibility tests of all strains were performed by disk diffusion test using 30 mcg cefoxitin disks and by agar dilution method using oxacilline base according to the recommendations of Clinical and Laboratory Standard Institute (CLSI) guidelines. Presence of FnBPs was investigated by detection of fnbA and fnbB genes via conventional PCR method. S. aureus NCTC 8325 was used to characterise the genes coding FnBP A and B as the reference strain.

Results: According to cultural properties and positive tube coagulase test all 50 isolates included in the present study were identified as S. aureus. All isolates were found to be susceptible to oxacilline (MIC < 1 mg/L). Of 50 S. aureus strains, 14 (28%) were found to be positive for gene fnbA and 5 (10%) for gene fnbB.

Conclusion: Presence of FnBPs in our study population was lower than the other studies performed on nasal carriers published previously. We concluded that the lower age of study population or geographical diversities could be resulted in this lower rate. Fibronectin binding proteins may represent an increased risk factor for subsequent infections but they are not efficient for adhesion alone.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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