In Vitro Synergistic Effect of Chlorpromazine with Imipenem Against Carbapenem-Resistant Klebsiella Pneumoniae

Abstract

This study was designed to determine the potential in vitro synergistic effects of chlorpromazine with imipenem against carbapenem-resistant Klebsiella Pneumoniae.  In this study, 63 isolates of carbapenem-resistant Klebsiella Pneumoniae (CRKp) were detected from 204 isolates of the bacteria obtained from clinical urine samples. Out of CRKp isolates, the majority (69.8 %) was carbapenemase-producing with variant susceptibility to polymyxin-B, colistin, tigecycline, ceftazidime-avibactam and rifampin. The minimum inhibitory concentrations (MIC) of chlorpromazine and imipenem against CRKp isolates were determined and concentrations above MIC were used to investigate the synergism between the two drugs qualitatively using paper strip diffusion. The relevant investigation indicated the presence of such synergism. Furthermore, determination of critical inhibitory concentrations (CIC), using agar diffusion method, of the two drugs individually and in combination assessed the synergism quantitively and demonstrated the potent synergistic effect of chlorpromazine with imipenem against CRKp which was probably due to inhibition of bacterial carbapenemase enzyme.