Clinical Microbiology and Antimicrobial Chemotherapy. 2014; 16(1):70-77
Staphylococcus aureus is known as the leading pathogen in hospital-acquired infections and the most common cause of skin and soft tissues. The present study aimed to test the genetic background of MSSA isolates obtained from pediatric patients and carriers (medical personnel and visitors) during local outbreak of exfoliative dermatitis. S. aureus isolates were analyzed by spa-, MLST-, coa-, SCC mec- и agr-typing, and 11 toxin- encoding genes were tested. All pediatric patient isolates were identical and have characteristics: S. aureus t272 (ST121). The main genomic features of this strain are genes of exfoliative toxins eta and etb, and the enterotoxin gene cluster. The analysis of the genetic structure of the S. aureus t272 (ST121) demonstrates clonal relationship with the strains circulating in France and the difference with the strains circulating in the Far East region. Isolates obtained from medical personnel and visitors divided to 9 S. aureus lineages. One isolate, S. aureus t284 (ST121), belongs to the genetic lineage, which can cause exfoliative dermatitis, but specific exfoliative dermatitis determinants are absent at the same time. The rest were belonging to the 8 genetic variants of S. aureus, which were not detected among strains causing exfoliative dermatitis. Most of the isolates were identified as the known spa types S. aureus: t002 (ST5), t012 (ST30) и t015 (ST45). These genetic lineages are characterized by high-frequency of horizontal virulence gene transfer, which includes SCC mec and toxin genes. All spa type t012 isolates carried toxic shock syndrome toxin gene and some of them carried the gene PantonValentine leukocidin.