ABSTRACT Background and Objectives: The resistance of gram-negative bacteria to antibiotics has become a serious problem, which imposes a significant increase in treatment costs. Klebsiella pneumoniae is an important nosocomial pathogen from the Enterobacteriaceae family. The aim of this study was to investigate the frequency and pattern of antibiotic resistance in K. pneumoniae strains isolated from clinical samples. Methods: This descriptive, cross-sectional study was performed on 150 K. pneumonia strains isolated from different clinical samples such as urine, sputum, blood, ulcers, lung secretions and abdominal abscess. Antibiogram test was performed using the disk diffusion method (Kirby-Bauer). Minimum inhibitory concentration of amikacin, tobramycin and gentamicin was determined via the E-test for 50 strains with high resistance rates. Results: In this study, the highest rate of resistance was observed against carbenicilin, ceftriaxone, cefepime and streptomycin. K. pneumonia isolates were most frequent in urine and sputum samples. In the E-test, the highest rate of resistance was observed against gentamicin, tobramycin (16µg/ml) and amikacin (64µg/ml). Conclusion: Based on our results, tigecycline, netilmicin, kanamycin and amikacin are the most effective antibiotics for the treatment of K. pneumoniae infections. Keywords: Klebsiella pneumoniae, antimicrobial resistance, E-test method
