Evaluation of the Antibacterial Activity of Piperacillin–tazobactam Against Burkholderia Pseudomallei in Vitro

Abstract Objective:Melioidosis is a zoonotic disease caused by Burkholderia pseudomallei (B. pseudomallei). Because B. pseudomallei is naturally resistant to a variety of antibiotics, such as penicillin, ampicillin, first-and second-generation cephalosporins, macrolides, aminoglycosides, streptomycin, polymyxin, etc., the selection of drugs is limited. The present study aimed to evaluate the antibacterial activity of piperacillin/tazobactam against B. pseudomallei in vitro to provide a theoretical basis and a variety of therapeutic options for clinical application.The antimicrobial susceptibilities of all B. pseudomallei isolated from melioidosis patients were detected by Etest method. Results: The MIC50 values of piperacillin/tazobactam, imipenem, meropenem, doxycycline, trimethoprim–sulfamethoxazole, ceftazidime, tetracycline, and amoxicillin/clavulanic acid were 0.25 μg/ml, 0.5 μg/ml, 0.5 μg/ml, 0.5 μg/ml, 1 μg/ml, 1 μg/ml, 2 μg/ml, and 2 μg/ml, respectively. Their MIC90 values were 0.5 μg/ml, 0.5 μg/ml, 1 μg/ml, 2 μg/ml, 2 μg/ml, 2 μg/ml, 4 μg/ml, and 4 μg/ml, respectively. All the isolates were uniformly sensitive (100%) to ceftazidime, imipenem and amoxicillin–clavulanic acid. The rate of antimicrobial sensitivity for doxycycline was 99.08%, for tetracycline-sulfamethoxazole 94.50%, and for tetracycline 94.49%.Both the MIC50 and MIC90 values of piperacillin/tazobactam were lower than those of the seven other antibiotics, indicating that it has strong antibacterial activity against B. pseudomallei in vitro.