Abstract

Background and Objective: Staphylococcus aureus is an important opportunistic pathogen causing a wide range of infections in human .Most clinical isolates of S.aureus are resistant to a number of antibiotics. For appropriate antimicrobial therapy, this study was conducted to determine antibacterial drug resistance patterns of S.aureus isolates obtained from different clinical samples in Rasht.

Material and Methods:  the clinical isolates of S.aureus were collected from different clinical laboratories in Rasht. Thirty coagulase positive S.aureus strains were identified using biochemical tests and amplification of 23SrRNA and coa genes by polymerase chain reaction.  Finally, the resistance pattern of the isolates to 16 selected antimicrobial agents was evaluated by disk diffusion method.

Results:  the S.aureus isolates (75%) were resistant to methicillin and all of them were multidrug resistance. The isolates were high resistance to ampicillin (73%), amoxicillin (60%), cloxacillin (53%) and low resistance to vancomycin (7%) and gentamicin (10%).

Conclusion: given the high prevalence of methicillin resistant, multi drug resistant and presence of vancomycin resistant S.aureus isolates in Rasht, continuously monitoring of drug resistance pattern of S.aureus isolates is recommended for having appropriate therapeutic regime.

Keywords: Staphylococcus Aureus, Coagulase, Drug Resistance, PCR

ABSTRACT
          Background and Objectives: Determining the genetic relationship between S. aureus isolates is important for epidemiological surveillance and control of infections caused by this bacterium. The present study was conducted to determine polymorphisms of coagulase gene (coa) among S. aureus isolates from pastry and cheese samples using restriction fragment length polymorphism (RFLP) analysis.
         Methods: Overall, 65 S. aureus isolated from pastry (n=45) and cheese (n=20) samples were examined for the coa gene by polymerase chain reaction (PCR). PCR products were digested with AluI enzyme and the products were assessed using gel electrophoresis.
          Results: Except for two isolates, all isolates were positive in coa-PCR and produced four different PCR products, with molecular sizes ranging from 570 to 970 bp. Overall; five distinct RFLP patterns were detected (I-V). Although pattern types I and III were present in isolates from both samples, types I and IV were mainly present in isolates from cheese and pastry samples, respectively.
        Conclusion: PCR-RFLP analysis of the coa gene indicates that S. aureus isolates from pastry and cheese samples may be originated from different sources. However, as one pattern type was predominant in each group, it can be concluded that majority of the isolates may have the same origin.
          Keywords: Staphylococcus aureus, PCR-RFLP, Coagulase, Pastry, Cheese.