Mupirocin‐Resistant <i>Staphylococcus aureus</i> in Iran: A Biofilm Production and Genetic Characteristics

Abstract

The spread of mupirocin-resistant <i>Staphylococcus aureus</i> strains in hospitals and communities is a universal challenge. Limited data is available on the genetic features of high-level mupirocin resistant- (HLMUPR-) <i>S. aureus</i> isolates in Tehran. In the present research, we investigated 48 high-level mupirocin resistance <i>S. aureus</i> by antimicrobial activity, virulence analysis, biofilm formation, multilocus sequence typing (MLST), and staphylocoagulase (SC) typing. All the HLMUPR strains were positive for <i>mupA</i> gene. The frequency of multidrug resistance was 97.9%. Twenty-one (43.8%) were toxinogenic with 14 producing <i>pvl</i> (29.2%), 5 <i>tst</i> (10.4%), and two <i>eta</i> (4.2%). Among the HLMUPR isolates, biofilm production was detected in 45 (89.6%) isolates with complete dominance <i>clfB</i>, <i>clfA</i> genes, and a noticeably high frequency <i>fnbA</i> (95.8%), followed by <i>fnbB</i> (93.8%), <i>eno</i> and <i>icaD</i> (each 83.3%), <i>sdrC</i> (81.3%), <i>ebps</i> (79.2%), <i>icaA</i> (75%), <i>sdrD</i> (66.7%), <i>fib</i> (60.4%), <i>sdrE</i> (50%), <i>cna</i> (41.7%), and <i>bap</i> (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 (<i>n</i> = 3) and CC8/ST239 (<i>n</i> = 1). Observations highlighted the circulation of the CC/ST22 HLMUPR <i>S. aureus</i> strains with strong biofilm-production ability in our hospitals, indicating the possibility of transmission of this type between community and hospital.