Prevalence and Antimicrobial Susceptibility of methicillin Resistant Staphylococcus aureus and Coagulase-negative staphylococci in the Southwest of Iran

Background and Objectives: Globally nosocomial infection is a major problem. Methicillin resistant Staphylococcus aureus (MRSA) and methicillin resistant coagulase negative staphylococci (MRCoNS) are the major causes of nosocomial infections. The aim of this study was to determine the prevalence and antimicrobial susceptibility of MRSA and MRCoNS in the southwest of Iran. Materials and Methods: This cross-sectional study was conducted on 221 non-duplicated staphylococci isolates collected from two tertiary care hospitals in Shiraz, southwest of Iran. The prevalence of MRSA and MRCoNS in clinical samples was identified using conventional microbiological tests. After identification of MRSA and MRCoNS, all the isolates were subjected to antimicrobial susceptibility test and polymerase chain reaction (PCR) to identify the presence of femA, mecA and pvl genes and their association with the clinical outcomes or antimicrobial resistance. Result: Among 168 S. aureus, 31.67% (70) were methicillin resistant and among 53 CoNS, 15.48% (26) were methicillin resistant in the study. The data showed that the highest resistance rates in both strains were observed against chloramphenicol (91.4%), ciprofloxacin (70%) and tobramycin (71.4%), respectively. The frequency of pvl gene among S. aureus strains was 3.57%. Conclusion: There is a need for continuous monitoring of the antimicrobial susceptibility pattern of MRSA and MRCoNS for selecting appropriate therapy, developing the antibiotic policy and limiting the use of powerful antibiotics.