Comparative study of in vitro activities of polymyxin B commercial products on Pseudomonas aeruginosa isolated from hospitalized patients

Abstract

Introduction: Polymyxin B has been applied as one of the last-resort antibiotics for the treatment of multidrug resistance among Gram-negative bacterial infections. Due to side effects such as renal toxicity, the use of polymyxin is associated with limitations. The present study evaluates in vitro antibacterial activity of a number of polymyxin B commercial products against Pseudomonas aeruginosa. Methods: This study included 63 non-duplicated P. aeruginosa isolates examined for in vitro polymyxin B susceptibility testing using the following powder disks: polymyxin B sulfate, otosporin, Poly-Mxb, and Myxacort. MIC50 and MIC90 have also been identified for polymyxin B antibiotics. Results: Myxacort had functional activity against most P. aeruginosa isolates, and only seven isolates had a relatively high MIC. The activities of Poly-MXb and Myxacort were the same as otosporin. Conclusions: Our findings revealed that the national generic polymyxin B product (Myxacort), and two external products (Otosporin, Poly-MXb) are similar in terms of microbiological activity.