MRSE and MRSH Genomic DNA Extraction

Total genomic DNA extraction was performed with the Cetyltrimethylammonium Bromide (CTAB) procedure as described by Nahaei et al. [16 (link)]. For final confirmation of methicillin-resistant S. epidermidis (MRSE) and methicillin-resistant S. haemolyticus (MRSH), the PCR method targeted the mecA gene was used. PCR conditions, the volume of materials, and primer sequence were set based on a previously published study by de Allori et al. [22 (link)]. Moreover, PCR analysis for icaA and icaD genes was performed using specific primers. The volume of materials, PCR conditions, and primer sequences have been described previously by Arciola et al. [23 (link)]. The PCR products were electrophoresed on 1.5% agarose gels in TBE buffer (89 mM Tris base, 89 mM boronic acid, 2 mM Na2, EDTA, pH 8.25). The gel was stained using the DNA-safe stain (SinaClon Co., Iran) and was observed under ultraviolet light. A 100 bp DNA ladder was used as a molecular size indicator.