Comparison of Antibiogram Results of Two Types of Antibiotic Discs and Validation by E.test Method on Bacteria with High Antibiotic Resistance Patterns

Abstract

Background and Objective: The increased resistance of microorganisms to common antibiotics is one of the major therapeutic challenges for patients. The present study aimed to compare the antibiogram results of two types of antibiotic discs and validate them by the Epsilometer test (E-test) method on bacteria with high antibiotic resistance patterns. Materials and Methods: This descriptive-analytical study was performed by the census method on 176 patients admitted to different wards of Sina Hospital in Hamadan from March 2016 to March 2019. The patients entered the study with a positive culture result and underwent the antibiogram using two types of discs. Following that, validation was performed by the E-test method in cases with significant differences. Finally, the results were described and analyzed in SPSS software (version 16) at a 95% confidence interval. Results: Out of 176 patients, 80 (45.4%) and 96 (54.5%) cases were male and female, respectively. The mean age of patients was reported as 62.44.±20.47 years. The most common culture sites were trachea (45.5%) and urine (42.6%), and the most common cultured microorganisms were E.coli (33.5%), Klebsiella (29.5%), and Acinetobacter (18.8%). The highest correlation coefficients of the results by disk diffusion method were observed in levofloxacin (r=1.00), piperacillin (r=0.917), ciprofloxacin (r=0.907), cotrimoxazole (r=0.904). On the other hand, the lowest correlation coefficients were related to imipenem (r=0.634), cefoxitin (r=0.556), and ceftriaxone (r=0.552). Conclusion: As evidenced by the obtained results, significant differences were detected between the results of antibiogram in Iranian and imported disks. After verification and validation using E.test, the percentage of agreement was in favor of imported disks.

Keywords

• antibiogram
• disk diffusion
• e.test