Background and objective: Bloodstream infections (BSI) are dangerous and if not treated appropriately will be accompanied by high mortality. the aim of this study was to determine the frequency of different etiological agents of BSI and their resistance to commonly used antibiotics.
Material and Method: This study performed by 129 positive blood culture samples collected during 2009 to 2010 from patients of tehran besat hospital. Antibiotic susceptibility testing was performed by using disk diffusion method as per clinical and laboratory standards institu (CLSI) guideline. Data analysed by Chi-square test and SPSS soft ware. P value of <0.05 was determined as significant.
Results: The most common causes of BSI were coagulase-negative staphylococcus (CONS) and E.coli 45(34.9%), 38(29.5%) respectively. Infections with proteus vulgaris was rare 2 (1.6%). Prevalence of gram negative infections in comparison with gram positive infections was (1.58:1). The highest resistance was demonstrated as: Penicillin 73.6% - Ampicillin 66.6% -Tetracyclin 58.9%. The highest susceptibility was demonstrated as Gentamicin and Imipenem 68.3%,65.9% respectively.
Conclusion: BSI caused by gram negative bacteria is 1.5 fold more than gram positive bacteria. In our hospital CONS and E.coli are more common etiological agents of BSI (64% of all infections). Vancomycin are suitable antibiotic for treatment of CONA and S.aureus infections.