Comparison of Antibiotic Susceptibility by Disc Diffusion Method Using Internal and External Disc Brands in High Resistance Bacteria

Introduction: Today, increasing the resistance of microorganisms to existing antibiotics is one of the most important treatment challenges in most countries. To determine the susceptibility of microorganisms against different types of antibiotics, both Iranian and imported brands can be used. Determining the degree of conformity of the results of internal discs with its external samples is one of the ways to reduce dependency, especially in sanctions conditions.Materials and Methods: In this descriptive-analytical study, with convenience simple sampling method, 176 different samples of patients who were admitted in different wards of Sina Hospital of Hamadan in northwest of Iran were enrolled for culture and antibiograms in 2017. For all patients with positive culture results, antibiogram were performed by disc diffusion method using Padtan (made in Iran) and MAST (made in England) antibiogram discs brands. The results were analyzed by SPSS software version 16 at 95% confidence interval. Pearson correlation coefficient and Kappa coefficient agreement were used to determine the degree of conformity between quantitative and qualitative variables, respectively.Results: The most common culture sample was taken from trachea (45.5%) and urine (42.6%), and the most commonly cultured microorganisms were E.coli (33.5%), Klebsiella (29.5%) and Acinetobacter (18.8%). In all cultured microorganisms, the kappa coefficient of agreement between Padtan and MAST disc antibiogram results, based on CLSI 2017, ranged from 0.114 to 0.986. Also, the highest coefficient of agreement was related to three antibiotics including Ciprofloxacin, Co-trimoxazole and Piperacillin, respectively and the lowest coefficient of agreement was related to in-order three antibiotics including Imipenem, Cefepime and Amikacin. Meanwhile, in the quantitative comparison method based on the measurement of non-growth zone diameter in millimeters, the correlation coefficient of the results using these two brands, was between 0.552 and 1.00.Conclusion:The results of this study showed that the results of Iranian and imported antibiogram discs brands, have an acceptable coefficient of agreement and correlation in high antibiotic resistance strains. But in cases of poor coefficient of agreement and correlation including Imipenem, Cefepime and Amikacin, accurate results may require the use of imported disc brands or more precise methods such as E-test to assist the patient.

کلیدواژه ها:

Antibiogram ، Disc diffusion