Comparison of toxin genes in staphylococcus aureus isolates obtained from patients and carriers

Abstract

It is important to have information about virulence characteristics of S. aureus isolates obtained from the nasal cultures of carriers in terms of the capability to cause severe infections. In the present study, S. aureus isolates obtained from carriers and isolates obtained from clinical specimens, and which were determined as causative agents of infection, were compared in terms of the genes of staphylococcal enterotoxin A and B (sea and seb), TSST-1 (tst), and PVL (pvl). A total of 44 S. aureus strains isolated from clinical specimens and 44 carrier isolates were tested for the genes with polymerase chain reaction method. As the results, the most common gene was sea with a rate of 45.5% (40/88). This gene was found in 34.1% (15/44) of the carrier isolates and in 56.8% (25/44) of the clinical group. Furthermore, the presence of the sea gene was found to be significantly higher in the clinical isolates than in the carriers' (P=0.032). The tst, seb, and pvl genes were positive at rates of 18.2% (16/88), 4.5% (4/88), and 5.7% (5/88), respectively. No significant differences were found between the groups according to positivity rates of the tst, seb, and pvl genes (p>0.05 for each gene) To our knowledge, differences between carrier isolates and clinical isolates in terms of toxin genes have not been investigated before the present study. The presence of sea at a significantly higher rate in clinical isolates shows the need for advanced molecular analysis on this topic.