Background: Most methicillin-resistant Staphylococcus aureus (MRSA) infections occur in health care settings; therefore, it is important to know about antimicrobial susceptibility, and carriage of virulence genes in S. aureus isolates. Objectives: The current study aimed at determining the prevalence of genes coding antimicrobial resistance, toxins, and adhesion factors among various SCCmec types of MRSA isolated from intensive care units (ICUs). Methods: From April 2016 to March 2017, a total of 200 MRSA species were isolated from various clinical samples of patients hospitalized in ICUs. The Kirby-Bauer disk diffusion method was employed to determine resistance pattern. Conventional polymerase chain reaction (PCR) assay was utilized to demonstrate antimicrobial resistance, toxins, and adhesion genes. Different SCCmec types of MRSA strains were determine by the multiplex PCR assay. Results: Antibiotic susceptibility testing revealed that all the isolates were sensitive to linezolid, teicoplanin, and vancomycin. The frequency of high-level mupirocin-resistant MRSA was 5.5%. The presence of resistance genes ant(4')-Ia, aac(6')-Ie/aph(2"), tetM, msrA, ph(3')-IIIa, ermA, msrB, ermB, ermC, and mupA were detected 73.5%, 60.5%, 57.5%, 37%, 36.5%, 34.5%, 24%, 17%, 15% and 5.5%, respectively. The most prevalent adhesion genes were clfA (93.5%) followed by clfB (90%), fnbA (81.5%), fnbB (77%), can (51%), ebp (46.5%), and bbp (2.5%). The frequency of etb, eta, pvl, and tst genes were 4.5%, 9.5%, 21.5%, and 61.5%, respectively. Inducible macrolide-lincosamidestreptogramin B (inducible MLSB resistance; iMLSB), and constitutive MLSB (cMLSB) phenotypes were observed in 88 (44%) and 26 (13%) isolates. Different SCCmec types comprising type III (56.5%), type IV (25%), type II (11%) and type I (7.5%) were identified among the MRSA strains. Conclusions: Results of the current study showed a high prevalence of resistance to commonly used antibiotics that can be a serious threat to patients hospitalized in ICUs. Also, the current study findings showed that different SCCmec types causing nosocomial infections were associated with specific antimicrobial resistance, adhesion, and toxin gene profiles.

Background: Urinary tract infection (UTI) is one of the most frequent types of infections in community and hospital settings. Objectives: 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. Methods: 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. Results: 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%). PantonValentine 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. Conclusions: 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.

The spread of mupirocin-resistant Staphylococcus aureus strains in hospitals and communities is a universal challenge. Limited data is available on the genetic features of high-level mupirocin resistant- (HLMUPR-) S. aureus isolates in Tehran. In the present research, we investigated 48 high-level mupirocin resistance S. aureus by antimicrobial activity, virulence analysis, biofilm formation, multilocus sequence typing (MLST), and staphylocoagulase (SC) typing. All the HLMUPR strains were positive for mupA gene. The frequency of multidrug resistance was 97.9%. Twenty-one (43.8%) were toxinogenic with 14 producing pvl (29.2%), 5 tst (10.4%), and two eta (4.2%). Among the HLMUPR isolates, biofilm production was detected in 45 (89.6%) isolates with complete dominance clfB, clfA genes, and a noticeably high frequency fnbA (95.8%), followed by fnbB (93.8%), eno and icaD (each 83.3%), sdrC (81.3%), ebps (79.2%), icaA (75%), sdrD (66.7%), fib (60.4%), sdrE (50%), cna (41.7%), and bap (4.2%). Coagulase typing distinguished isolates into four genotypic patterns including III (50%), II (27.1%), and type IVa (22.9%). A total of three clonal complexes (CCs) and 4 sequence types (STs) including CC/ST22 as the most prevalent (52.1%), CC8/ST239 (20.8%), CC/ST8 (16.7%), and CC/ST5 (10.4%) were identified in current work. According to our analysis, nonbiofilm producer isolates belonged to CC8/ST239 (6.3%) and CC/ST8 (4.2%). Fusidic acid-resistant isolates belonged to CC/ST45 ( n = 3 ) and CC8/ST239 ( n = 1 ). Observations highlighted the circulation of the CC/ST22 HLMUPR S. aureus strains with strong biofilm-production ability in our hospitals, indicating the possibility of transmission of this type between community and hospital.