Exploring the Synergistic Potential of Thymol/Ceftazidime against Acinetobacter baumannii: A Novel Therapeutic Approach
Exploring the Synergistic Potential of Thymol/Ceftazidime against Acinetobacter baumannii: A Novel Therapeutic Approach
sajjad jafari,1,*Mina Shirmohammadpour,2Mahsa Ghanizadeh Pirlo,3Mansour Khakpour,4Bahman Mirzaei,5
1. Department of Microbiology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, West Azerbaijan, Iran 2. Department of Microbiology and Virology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran 3. Department of Microbiology, Faculty of Mizan Institute of Higher Education, Tabriz, Iran 4. Department of Microbiology, Faculty of Mizan Institute of Higher Education, Tabriz, Iran 5. 1Department of Microbiology and Virology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
Introduction: This study aimed at the antimicrobial effects of thymol/ceftazidime on Acinetobacter baumannii bacteria.
Methods: Antimicrobial effects of thymol/ceftazidime were performed first individually and then combined on A. baumannii ATCC 19606 by the MIC-MBC method. Therefore, the antimicrobial effects of the compounds that had a synergistic impact were performed on eighteen clinical strains using the MIC-MBC method. The identification of chemical bonds, functional groups, and molecular interactions of the mentioned compounds was investigated using an FTIR device. Checkered method, time killing curve, and biofilm inhibition on A. baumannii ATCC 19606, investigation of cytotoxicity on red blood cells (RBCs) by hemolysis method and human skin fibroblast cells (Ffk) by MTT method were performed. Thymol/ceftazidime had synergistic effects.
Results: The study's findings demonstrated that when applied to A. baumannii ATCC 19606, the antimicrobial activities of thymol, ceftazidime, and thymol/ceftazidime (A4 compound) were, respectively, 256 µg/ml, 128 µg/ml, and 1024/256 µg/ml (FICI: 1 µg/ml). The A4 compound exhibited antibacterial activity of 256-1024/4-16 µg/ml on clinical strains of A. baumannii, respectively. Compared to the individual modes, the combined mode had a longer time curve for eliminating A. baumannii. Examination with FTIR showed that these two compounds have C=C conjugated, C≡C compound. Thymol, ceftazidime, and other chemicals have biofilm inhibition rates of 11%, 18.51%, and 23.41%, respectively against A. baumannii bacteria. The toxicity of thymol, ceftazidime, and A4 compound against human RBCs were 36.12, 8.33, and 8.38, and against human Ffk cells were 19.66, 7.08, and 9.03 respectively.
Conclusion: This study proved that the thymol/ceftazidime could become one of the new drugs for treating A. baumannii infections due to its high antimicrobial effects and low toxicity.