Profile of erythromycin resistance genes ermA, B, C and msrA in Staphylococcus aureus strains isolated from Ahvaz hospitals

Staphylococcus aureus is currently one of the main causes of nosocomial. The present study aimed to evaluate erythromycin resistant genes in Staphylococcus aureus strains isolated from clinical samples obtained from hospitals. In this study, 100 patients with positive S. aureus in clinical samples were collected from hospitals in Ahvaz. Resistance to antibiotics erythromycin, tetracycline, penicillin and clindamycin using antibiogram disks on all samples of blood, urine, sputum and trachea was tested. The presence of four genes involved in antibiotic resistance, namely ermA, ermB, ermC and msrA were determined by PCR in genome and plasmid. Also 21 samples with positive ermC gene were sequenced for evaluation of genetic variation. Molecular analysis showed that 64 samples were resistant to erythromycin while 87.5%, 93.8%, 92.2% and 70.3% of samples were positive in ermA, ermB, ermC and msrA respectively and 25 samples were susceptible to erythromycin including % 88 ermA, 92 % ermB, 100% ermC and 48% msrA with P value of: 0.23, 0.66, 0.31 and 0.83 showed no significant differences between susceptible and resistance to erythromycin samples. The presence of erm genes in erythromycin susceptible samples may be due to mutations in promoters or coding regions of genes which may inhibit their functions. Also the results of sequencing of ermC gene proved presence of this gene on plasmids.