بررسی مقاومت آنتی بیوتیکی باکتری های پاتوژن جداشده از تجهیزات پزشکی و محیط بیمارستان در مرکز آموزشی درمانی ولیعصر اراک در سال ۱۳۹۲

Background and purpose: Nosocomial infections are a major health problem worldwide. Hospital environment is a reservoir for nosocomial pathogens. This study aimed at determining the prevalence of antimicrobial resistance pattern of bacteria isolated from the environment and medical equipment in Valiasr Hospital in Arak. Material and Methods: A total of 210 samples was collected from hospital and identified. Inducible clindamycin resistance in Staphylococcus was determined with D Zone and sensitivity to vancomycin was identified by using Mueller Hinton agar and E-test. The sensitivity of these strains to cefoxitin and oxacillin was determined by disk diffusion method. The resistance was confirmed by investigating the presence of mec A gene using PCR technique. To identify the ESBL producing gram-negative bacill standard method was used. Amp C beta lactamase resistance was assessed by Amp C disk test, and for carbapenemase resistant MHT was applied. E-test with imipenem and imipenem+EDTA were used to identify the resistance pattern of metalo beta lactamase. Results: There were 240 isolates of which 185 (77%) were Staphylococcus. Among these isolates 136 (73.5%) were resistant to oxacillin and cefoxitin. Inducible clindamycin resistance was found in 46 (25%) isolates. Two samples of the Staphylococcus epidermidis were vancomycin resistant. The presence of Sa442 genes in Staphylococcus aureus and the mecA gene of MRSA was confirmed in all isolates expect in two. The frequency of gram-negative bacteria was 55(23%). ox51 gene was identified in acinetobacter baumannii. Fifteen nonfermenting gram-negative bacill and 40(65%) strains of Enterobacteriaceae were ESBL producers. Among the Klebsiella pneumoniae six (33.33%) were AmpC producers. MHT positive was found in nine (60%) nonfermenting bacills. Conclusion: According to this study presence of microorganisms in Valiasr Hospital environment and high incidence of antibiotic resistance are considered as major health problems. By determining potential pathogens in hospital setting and the pattern of antibiotic resistance markers physicians can perform more successful treatments.