Effects of Curcumin on Biofilm Production and Associated Gene inMultidrug-Resistant Acinetobacter baumannii Isolated from HospitalizedPatients

Document Type : Original Article

Authors
Kasra Javadi 1
Mohammad Hossein Ahmadi 1
Mehdi Rajabnia 2
Mehrdad Halaji 2
1 Department of Microbiology, Faculty of Medicine, Shahed University, Tehran, Iran.
2 Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran.
10.22088/IJMCM.BUMS.14.1.567
Abstract
Multi-drug-resistant (MDR) Acinetobacter baumannii has become a major global healthcare concern
due to its opportunistic infections and high antibiotic resistance. This investigation is intended to
investigate curcumin's potential anti-bacterial and antibiofilm impacts on MDR A. baumannii and to
present a promising strategy for fighting against infections caused by this pathogen. This cross-
sectional investigation comprised 34 MDR A. baumannii clinical isolates. The Kirby-Bauer disc
diffusion method evaluated the sensitivity of isolates to multifaceted anti-bacterial agents. The
microdilution broth method quantified curcumin's minimum inhibitory concentration (MIC) and the
minimum bactericidal concentration (MBC). The efficacy of curcumin in inhibiting MDR A.
baumannii biofilm was assessed via 96-well microtiter plates. The expression of the biofilm-
associated protein (bap) gene was evaluated by employing quantitative real-time PCR (qRT-PCR).
Within the 34 MDR A. baumannii isolates, the highest resistance was noted for
trimethoprim/sulfamethoxazole and ciprofloxacin, with all 34 isolates (100%) indicating resistance.
The lowest resistance was noted for ampicillin/sulbactam, with 22 isolates (64.7%) exhibiting
resistance. The MICs of curcumin ranged from 0.625 to 2.5 mg/ml, while the MBCs varied between
1.25 to 5 mg/ml. Curcumin reduced biofilm formation by 25% to 91%, depending on the
concentration. In contrast to the untreated control, the average relative activity of the bap gene in
MDR A. baumannii isolates declined by 62.07%. The findings indicate that curcumin demonstrates
antimicrobial and anti-biofilm activities against MDR A. baumannii. The downregulation noted in
the bap gene further supports the curcumin's anti-biofilm impact.
Keywords
Acinetobacter baumannii
Multidrug-resistance
Curcumin
Biofilm