In vitro antimicrobial activity of Cinnamomum verum, Allium sativum, and Zingiber officinale extracts on metallo-β-lactamase-producing Acinetobacter baumannii: A potential therapeutic approach

Introduction and Objectives: Metallo-β-lactamase (MBL)-producing Acinetobacter baumannii is a leading cause of nosocomial infections, especially in burn patients worldwide. The antimicrobial properties of Cinnamomum verum, Allium sativum, and Zingiber officinale known as cinnamon, garlic, and ginger, respectively have not yet been reported in clinical isolates of A. baumannii producing metallo-β-lactamase. The present study was aimed to detect MBL genes and evaluate the inhibitory effect of cinnamon, garlic and ginger extracts on MBL-producing A. baumannii.Materials and Methods: Antibiotic resistance pattern of MBL-producing A. baumannii isolates was evaluated by Kirby-Bauer disk diffusion method. MBL-producing isolates were phenotypically tested by combined disk test (CDT). The prevalence of blaVIM-1 and blaIMP-1 genes encoding metallo-β-lactamase were detected by PCR. Minimum inhibitory concentration (MIC) of the acetonic, methanolic, and chloroformic extracts of cinnamon, garlic, and ginger on MBL-producing isolates was evaluated by the broth microdilution method.Results: 92 out of 105 (87.6%) multi drug resistant A. baumannii isolates were MBL-producing strains. 11 out of 92 (11.9%) and 7 out of 92 (7.60%) MBL-producing A. baumannii were positive for blaIMP-1 and blaVIM-1 genes, respectively. The inhibitory concentrations of the acetonic, methanolic, and chloroformic extracts of cinnamon, garlic, and ginger ranged from ≥0.78 mg/ml to ≥12.50 mg/ml.Conclusion: We find that the chloroformic, methanolic, and acetonic extracts of cinnamon, garlic, and ginger, respectively has significant antibacterial activity against the MBL-producing A. baumannii. This medicinal plants can be considered as a source of forgotten antimicrobial agents to avoid treatment failure and mortality.

Keywords:

Metallo-β-lactamase , Acinetobacter baumannii , Cinnamon , Garlic , Ginger