ABSTRACT
OBJECTIVE: Silybin and curcumin have potential antimicrobial effects. This study aimed to evaluate the synergistic antimicrobial effects of silybin and curcumin on virulence and carbapenemase genes expression among multidrug-resistant (MDR) Klebsiella oxytoca. RESULTS: A total of 70 MDR K. oxytoca (carrying blaIMP and blaOXA-48-like genes) were included. The antibiotic susceptibility and biofilm production of isolates were determined. The silybin and curcumin at concentrations 10-500 mg/mL alone and in combination were exposed to bacterial isolates in Mueller Hinton broth medium for 24 h. The expression of blaIMP, blaOXA-48-like, mrkA, pilQ, matB and fimA genes was evaluated using quantitative real-time polymerase chain reaction (qRT-PCR). The mean minimum inhibitory concentration (MIC) of curcumin and silybin were 250 mg/mL and 500 mg/mL, respectively. The anti-virulent effect of 100 mg/mL of silybin and curcumin was shown by significant reduction in the expression of fimA (2.1-fold, P < 0.0001) and mrkA (2.1 fold, P < 0.0001) genes. Moreover, these compounds significantly decreased the expression of blaIMP1 (3.2-fold, P < 0.0001) gene. Notably, there was no significant effect on pilQ, matB and blaOXA-48-like genes. The results showed that silybin and curcumin can be candidate as natural way for control the MDR virulent strains of K. oxytoca.
