Journal of Global Antimicrobial Resistance (Dec 2024)
Antibiotic Resistance and Genotypic Diversity of CC45-MRSA Isolates In Kuwait Hospitals
Abstract
BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) belonging to clonal complex 45 (CC45-MRSA) is rare in Kuwait. This study aimed to characterize MRSA isolates identified as CC45-MRSA by DNA microarray for antibiotic resistance and genetic backgrounds. METHODS: A total of 91 CC5-MRSA isolates obtained from clinical samples between 2016 and 2022 were investigated. Antibiotic resistance was determined by disc diffusion, and MIC determination. Staphylococcal protein A (Spa) typing was used to investigate genetic relatedness. RESULTS: The isolates were resistant to penicillin G (n=91), fusidic acid (n=71), erythromycin (n=16), inducible clindamycin (n=15), ciprofloxacin (n=11), trimethoprim (n=4) and gentamicin (n=2), and harbored blaZ, fusC, erm(C), dfrS1, and aacA-aphD. The isolates belonged to 25 spa types, dominated by t362 (29.6%), t132 (14.2%), followed by t004 (3.3%), t026 (2.2%), t050 (2.2%), t1575 (2.2%) and t2674 (2.2%), and nine genotypes with CC45-MRSA-IV+SCCfus (n=27), CC45-MRSA-[VI +fus] (n=22), CC45-MRSA-IV, Berlin EMRSA (n=17) and CC45-MRSA-[IV+fus] (n=9) constituting 93.4% of the isolates, CC45/agrIV-MRSA-V (n=5), CC45-MRSA-IV(tst1+) (n=3), CC45-MRSA-V (n=3), CC45-MRSA-V [tst1+], WA MRSA-4 (n=4), and CC45-MRSA-V [PVL+] (n=1). Eighty-six (94.5%) isolates belonged to accessory gene regulator type 1, while five belonged to type IV. All CC45-MRSA isolates harbored genes for capsular polysaccharide type 8, immune evasion cluster (staphylokinase, chemotaxis-inhibiting protein, and staphylococcal complement inhibitor), but harbored varied enterotoxins, and toxic shock syndrome toxin genes. One isolate was positive for Panton-Valentine Leukocidin. CONCLUSIONS: The diverse genetic backgrounds suggest independent acquisition of the CC45-MRSA isolates. The high prevalence of fusidic acid resistance in the dominant genotypes is disturbing.
