SCCmec and spa Typing of Staphylococcus aureus Strains Isolated from Patients with Urinary Tract Infection: Emergence of spa Types t426 and t021 in Iran

Urinary tract infection (UTI) is one of the most frequent types of infections in community and hospital settings.
The aim of the present study was to investigate antimicrobial susceptibility patterns and also to determine spa and SCCmec types of Staphylococcus aureus strains isolated from patients with UTI.
During a 12-month period, 863 urine samples were investigated. In vitro susceptibility of isolates was performed using the Kirby-Bauer disk diffusion method. Moreover, conventional PCR was performed to detect mecA, nucA, spa, and toxin (pvl, tst) genes as well as Multiplex PCR to determine SCCmec types.
A total of 90 isolates (10.4%) were analyzed in the present survey. Methicillin resistance was observed in 61.1% of the isolates. In total, 25 isolates (27.8%) were positive for the pvl-encoding gene and 40 (44.4%) for tst-1 encoding gene. Based on a multiplex PCR assay, the 4 different SCCmec types were detected as type III (38.9%), followed by type II (31.1%), type IV (28.9%), and type I (1.1%). Panton-Valentine Leukocidin (PVL) positive isolates belonged to SCCmec type IV (14.4%) and II (13.3%). The 90 S. aureus isolates were classified to 10 spa types t037 (23.3%), t924 (15.6%), t383 (15.6%), t426 (12.2%), t044 (12.2%), t790 (6.7%), t084 (4.4%), t021 (4.4%), t7580 (4.4%), and t064 (1.2%). The spa types t044, t790, and t084 were obtained from methicillin-resistant S. aureus (MRSA) strains and spa types t924 and t7580 from methicillin-sensitive S. aureus strains.
To the best of the author’s knowledge, this is the first study on spa types t426 and t021 in Iran. Since the majority of strains isolated from patients with UTI were MRSA, detection of MRSA clones and their characteristics is necessary.