Characteristics of Prophage Patterns and Virulence Gene Profiles among Methicillin-Resistant Staphylococcus aureus Isolates from Patients with Diabetic Foot Infections in a Referral Hospital in Tehran, Iran

Diabetic patients are at risk of developing serious foot infections with methicillin-resistant Staphylococcus aureus (MRSA) strains, which are associated with high morbidity and mortality. This study aimed to investigate the frequency of different prophage types and virulence factors among MRSA strains isolated from patients with diabetic foot infections (DFIs) in a referral hospital in Tehran, Iran during 2019 and 2020.

A total of 238 S. aureus isolates were collected and confirmed using specific primers. The presence of staphylococcal enterotoxins (sea-seq) and hlb, sak, eta, etb, and tsst-1 genes among MRSA isolates was tested using separate polymerase chain reaction (PCR) assays. Also, multiplex PCR was employed for prophage typing of MRSA isolates.

A total of 73 (31%) isolates were confirmed as MRSA, among which four prophage types and 13 different prophage patterns were identified, and prophage type SGF and prophage pattern 7 consisting of SGB, SGF, SGFa, and SGFb types were the dominant ones. Also, 11 enterotoxin-encoding genes and four virulence factor genes were detected among the isolates. All MRSA isolates were positive for sea, sek, seq, and hlb genes. Moreover, out of 12 different enterotoxin patterns, most MRSA isolates were classified into enterotoxin pattern 1, harboring three enterotoxin genes (sea, sek, and seq).

This study results indicated the presence of different prophage types and virulence factor genes among MRSA strains isolated from DFI patients, which enable them to produce a variety of diseases.