Prevalence of erm Gene among Clinical Isolates of Staphylococcus aureus in Shahrekord, Iran

Abstract

<strong>Background:</strong> Development of drug resistance to<em> Staphylococcus aureus</em> <em>(S. aureus) </em>has led to the use of older antibiotics such as macrolide-lincosamide-streptogramin B (MLSB) for the treatment of infections. MLS_B resistance can be caused by several mechanisms, however, one of the predominant reasons is target modification mediated by <em>erm </em>genes. The objective of this study is to determine the prevalence of <em>erm</em> genes and the frequency of constitutive MLS_B (cMLS_B), inducible MLSB (iMLS_B), and MS phenotypes using D-test and polymerase chain reaction (PCR) methods<strong>.</strong> <strong>Methods:</strong>D-test was performed on 110 clinical specimens of <em>S. aureus</em> collected from Kashani and Hajar Hospitals in Shahrkord from October 2014 to May 2015. After sampling, DNA extraction was performed by simple boiling method and, in order to detect <em>erm</em> genes, multiplex PCR was carried out on erythromycin resistant isolates using specific primers. <strong>Results:</strong>The result of this study revealed that among 110 <em>S. aureus</em> isolates examined, 35 (31.8%) were MRSA and frequency of cMLS_B, iMLS_B, and MS resistant phenotypes were 22 (20%), 9 (8.2%), and 2 (1.8%), respectively. The genes <em>ermA</em>,<em> ermB</em>, and<em> ermC</em> were detected in 27 (24.5%), 28 (25.4%), and 26 (23.6%) isolates. <strong>Conclusion:</strong>This study demonstrated that cMLS_B was the most common phenotype among isolated <em>S. aureus</em>. Moreover, another interesting point to notice in our study was the high frequency of the <em>ermB</em> gene in iMLS_B resistant phenotypes.