The Correlation between Defined Daily Doses of Antibiotics with the Antimicrobial Resistance of Microorganisms Separated from Patients with Nosocomial Infections

Abstract Background & aim: Infection with resistant microorganisms in intensive care units (ICUs) is more prevalent than other parts of the hospital. The aim of this study was to determine the relationship between the daily dose of the antibiotic resistance and patterns of microorganisms isolated from patients with nosocomial infections. Methods: This cross-sectional study was conducted in a period of 9 months in three wards of ICU, internal medicine, neurosurgery of Namazi Hospital of Shiraz. The World Health Organization definition was used for determining the daily Dose. The sensitivity test of microorganisms to antibiotics was determined by E-test. The collected data were analyzed with Pearson test. Results: The highest incidences of nosocomial infection were observed in intensive care medicine and surgery, respectively. The total amount of consumed antibiotics were seen in intensive care of surgery, internal medicine and neurosurgery were 100.29 DDD/100 bed days. Uses of cephalosporins, especially third generation cephalosporins show the highest amount. The resistance rate of gram-negative bacteria such as Acinetobacter, Pseudomonas and Enterobacter to ceftriaxone were100, 100 and 82.4% respectively. Conclusion: The results of study showed that there was a relationship between antibiotic consumption and resistance of microorganisms. Although other variables than the antibiotic consumption causing antibiotic resistance should not be ignored. Key words: Defined daily dose, Intensive care unit, Antibiotics, Antibiotic resistance, Nosocomial infectio