Molecular Typing of Community‑acquired Methicillin‑Resistant Staphylococcus aureus Isolated from 2‑ to 6‑year old Children by Staphylococcal Protein A and Agr Typing in Isfahan, Iran

Methicillin‑resistant Staphylococcus aureus (MRSA) has become a considerable public health concern in the entire world due to the rapid spread of this bacterium in human community; also the epidemiology of MRSA has changed, as the isolation of MRSA strains from healthy and non‑healthy patients. Therefore, the objective of this study is to determine the genetic diversity and antibiotic resistance profile of community‑acquired (CA)‑MRSA nasal carriage in the Iranian samples.

A total of 25 CA‑MRSA were isolated from the anterior nares of 410 healthy preschool children. All MRSA isolates were characterized by the detection of the toxic shock syndrome toxin‑1 (TSST‑1) and typed by γ‑hemolysin genes, agr groups, and staphylococcal protein A (spa) typing. Kirby‑Buyer antibiotic susceptibility testing was performed and interpreted as per the standard guidelines.

A total of 25 (6.1%) MRSA isolates were recovered from the anterior nares of 410 preschool children. Sixteen isolates (64%) were positive for the TSST‑1 gene. Three agr specificity groups were determined, as follows: eight (32%) isolates belonged to agr Group I, five (20%) isolates belonged to agr Group II, and 12 (48%) isolates belonged to agr Group III. The repeated profiles of these spa types of 25 isolates were organized into eight different lineages groups. Five of lineages contained a single strain, three of lineages contained two strains, and three of lineages consisted of more than three strains.

The results of our study show that the rate of MRSA in our region is significantly high. Additionally, spa type t037 was the predominant type among CA S. aureus.