Antibiotic Resistance Pattern of Hospital Isolates of Staphylococcus aureus in Mashhad-Iran During 2009 - 2011

Background: Staphylococcus aureus is a major human pathogen. Due to high prevalence of S. aureus infections and increasing resistance to antibiotics, physicians have been facing problems in choosing the appropriate empirical antibiotic therapy for such infections. Objectives: The aim of this study was to determine the pattern of antibiotic resistance in S. aureus clinical isolates of Mashhad Quaem Hospital between 2009 and 2011. Materials and Methods: In this study 170 isolates of Staphylococcus aureus were identified in laboratory. The specimens (including 82 urine, 43 wound, 37blood, 8 stool samples) were collected and examined by standard diagnostic methods. Determination of S. aureus sensitivity to antibiotics was performed using standard disc diffusion method. The antibiotic sensitivity of bacteria were reported according to the clinical laboratory standards institute (CLSI) manual as sensitive (S), intermediate (I) and resistant (R). Results: Among tested antibiotics, Staphylococci isolates were highly resistant against Ceftazidime (94%), followed by Penicillin (91%), Ampicillin (82%), Cefotaxime (65%), Erythromycin (60%), and Oxacillin (43%). Nearly all strains were susceptible to tested Vancomycin. Conclusions: Our results are similar to the reports from other parts of Iran. According to this study, resistance pattern among Staphylococcus aureus strains were widespread in Quaem hospital. The implication of this high resistance is that Staphylococcus aureus infections should be treated more consciously and not with Penicillin and other ineffective antibiotics.