multidrug resistance pattern of bacterial agents isolated from patient with chronic sinusitis

background: treatment of chronic sinusitis is complicated due to increase of antibiotic-resistant bacteria. the aim of this study was to determine the multidrug resistance (mdr) pattern of the bacteria causing chronic sinusitis in north of iran. methods: this cross-sectional study was carried out on patients with chronic sinusitis. bacterial susceptibility to antimicrobial agents was determined according to the clsi 2013 standards. double-disk synergy (dds) test was performed for the detection of extended-spectrum beta-lactamase (esbl) producing bacteria; also methicillin-resistant staphylococcus (mrsa) strains were identified by mrsa screen agar.  the mdr isolates were defined as resistant to 3 or more antibiotics. data were analyzed using spss 17 software. descriptive statistics was used to describe the features of the data in this study. results: the rate of esbl-producing bacteria was 28.75-37.03% among enterobacteriaceae and the rate of mrsa was 42.75%-60% among staphylococcus strains. the most detectable rate of the mdr bacterial isolates was gram-negative bacteria 39 (76.47%) and enterobacter spp. 19(70.37%) was the most multidrug resistant isolate among gram negative bacteria. also 36 (73.46%) of the gram positive bacterial isolated were multidrug resistance and staphylococcus aureus 9(90%) was the most mdr among gram positive bacteria. conclusion: antimicrobial resistance is increasing in chronic bacterial sinusitis. the emergence of mrsa and esbl bacteria causing chronic sinusitis is increasing