بررسی فراوانی استافیلوکوکوس اورئوس های مقاوم به متی سیلین دارای ژن mecA درنمونه های بدست آمده از بیماران مراجعه کننده به بیمارستان های آموزشی شهر اهواز، ایران

Title

Prevalence of Methicillin-Resistant Staphylococcus aureus with MecA Gene Isolated From Admitted Patients in Teaching Hospitals in Ahvaz City, Iran

English Abstract

Background & Objectives: Staphylococcus aureus is a major cause of nosocomial infections, osteomyelitis, myocarditis, pneumonia in children, skin abscesses and infected surgical wounds. Methicillin is one of the most important antibiotics that used in treatment of S. aureus infections, however, resistance to this antibiotic has been raised in recent years. The aim of this study was detection of mecA gene in methicillin-resistant S. aureus (MRSA) which were isolated from admitted and hospitalized patients. Methods: 255 isolates suspected to S. aureus were collected from patients in three teaching hospitals in Ahvaz city, Iran, during 2011. These strains were isolated from different specimens and identified using microscopic and standard biochemical tests. S. aureus strains phenotypically resistance to methicillin were screened after determination of drug resistance patterns of these strains against 10 antibiotics by disk diffusion Methods. Then, DNA was extracted from MRSA and mecA gene was amplified by PCR. Results: Out of 255 suspected isolates, 180 strains were confirmed as S. aureus. The examined specimens were as follow: lesions (36.1%), catheters (13.8%), blood (13.3%), trachea (5%), abscesses (5%) , urine (2.7%) and the other specimens(24.1%). Antibiogram results and the rate of sensitivity to examined antibiotics were as follow:Vancomycin (100%), nitrofurantoin (98.3%), chloramphenicol (98.3%), rifampin (90%), Norfloxacin (71.1%), gentamicin (69.4%), ciprofloxacin (67.2% ), azithromycin (66.7%), oxacillin (62.8%), cotrimoxazole (60.6%).These results also showed that out of 180 strains of S. aureus, 59 strains (32.8%) were phenotypically resistance to methicillin which among them, the mecA gene were confirmed in 58 strains by PCR. Conclution: The results of this study showed that all of S. aureus (100%) isolates were susceptible to Vancomycin although, nearly one third of them were resistance to methicillin. We believe Vancomycin could be used as a choice drug for treatment of Staphylococcal infections, especially MRSA, but based on some of the reports about Vancomycin-resistant S. aureus (VRSA), determination of MIC and sensitivity of S. aureus isolates to Vancomycin is necessary for prevention of spreading of VRSA in community.

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