Determination of antibiotic resistance and virulencedeterminants of different methicillin resistant and –sensitive S. aureus (MRSA & MSSA) types isolated from Shahid Mustafa Khomaini Hospitalof Ilam city by PCR, SCCmec and PFGE typing

Background and Aim : Staphylococcus aureus as a multi-capacity pathogenic bacterium whichholds virulence factors of antibiotic resistance is considered as one of the threatening factor forhuman life. Air conditions, hospital personnel and different surfaces have important roles intransferring of this bacterium among patients and hospital wards. Due to an increasing trend ofantibiotic resistance and pathogenesis ability of these strains (MRSA) globally and also in ourcountry, a proper planning for determining of the distribution source of theses strains in thecommunity and control of their associated infections is very necessary.Methods : Samples were taken from air, environment, personnel and patients admitted to differentwards of shahid Mstafa Khomeini Hospital in Ilam city, every four weeks for ۷ months. Strainsidentities were determined using standard biochemical tests as well as via tracing of spa and femAgenes. Identification of sensitive and residence strains to methicillin was performed using the testof sensitivity to cefoxitin via disk diffusion method and tracing of mec A gene by PCR.Antiobiogram was performed using ۱۱ different antibiotics. The ۱۳ virulence genes and ۱۲antibiotic resistance genes were studied via multi-PCR method and finally the methicillinresistance strains were typed using the SCCmec typing method. The current study aimed todetermine the type of MRSA by pulsed field gel electrophoresis (PFGE).Results : Totally ۸۸ strains were isolated from different samples including surfaces (۳۸.۹%),personnel (۲۶.۶%), air (۲۳%) and patients (۱۱.۹%). All strains were sensitive to linezolid,vancomycin, synercid, tigecyline, mupirocin, imipenem. Resistance to tetracycline, erythromycin,cefoxitin and gentamicin, clindamycin was ۱۰۰%, ۳۱.۹%, ۲۳.۶% ۱۳.۳% and ۸.۹% ,۸.۹%respectively.Among ۳۳ different pulsotypes, ۲۰ pulsotypes were known as the most frequentpulsotypes and ۱۳ pulsotypes were found as a single.Conclusion : . Nosocomial infections by Staphylococcus aureus particularly MRSA strains areamong worrisome problems in Iran. On the other hand personnel and environments of hospitalwards are often responsible for distributing of staphylococcus isolates. In the current studySCCmec types detected from patients and surfaces were the same that indicated a circulation ofMRSA between patients and hospital environment. Therefore an intensive and accurate control ofhospital environment for this infection is essential.

کلیدواژه ها:

MRSA ، PFGE