High frequency of exfoliative toxin genes among Staphylococcus aureus isolated from clinical specimens in the north of Iran: Alarm for the health of individuals under risk

Exfoliative toxins (ETs) of Staphylococcus aureus are the main reason of scalded skin syndrome in infants and young children. The aim of this study was to investigate the prevalence of eta, etb and etd genes in S. aureus.
A total of 150 S. aureus isolates were collected from clinical specimens during the years 2014 to 2016 in the north of Iran. After confirmation of the species using standard diagnostic procedures, polymerase chain reaction was used for detection of the eta, etb and etd genes among the isolates.
Overall, 131 (87.3%) isolates were positive for at least one of the ET genes; 11 (76.7%), 25 (16.7%) and 81 (54%) of the isolates carried the eta, etb and etd genes, respectively. Although eta and etd genes were present in all types of clinical samples, etb was found only in the wound, synovial fluid, sputum and tracheal aspirate. Overall, 7 toxin genotypes were observed, among which the genotypes eta-etd, eta and eta-etb-etd predominated at rates of 35.3%, 26.7% and 9.3%, respectively.
Detection of the high rate of prevalence of ET genes in the current study is considered as a serious problem because it is likely to spread and transfer these genes between strains. Furthermore, these isolates circulating in the community, particularly from infants, old people and immunocompromised patients, are important health-wise.