Antibacterial and antibiofilm activity of cinnamaldehyde against carbapenem-resistant Acinetobacter baumannii in Egypt: In vitro study

Abstract

Acinetobacter baumannii has emerged as a problematic nosocomial pathogen due to its antibiotic resistance as well as its ability to colonize and cause serious infection among patients. This study aimed to evaluate the ability of A. baumannii to form biofilms as well as to investigate the antibacterial activity of cinnamaldehyde against carbapenemresistant strains of A. baumannii. A total of 23 A. baumannii clinical strains were screened for their ability to form a biofilm using tissue culture plate method. Cinnamaldehyde antibacterial ability was investigated on planktonic cells and its biofilm inhibition ability was tested. Scanning electron microscopy (SEM) was applied to confirm the antibiofilm effect of cinnamaldehyde. Biofilm formers (86.95%) were categorized into strong (17.39%), moderate (52.17%), and weak (17.39%). Cinnamaldehyde showed a strong antimicrobial activity against planktonic cells of A. baumannii at low concentrations. The best antibiofilm activity was achieved at 1/2 minimum inhibitory concentration (MIC) and 1/4 MIC causing inhibition percentages ranging from 49.5% to 71.2% and 18.5% to 29.6%, respectively. Cinnamaldehyde exerted strong antimicrobial and antibiofilm properties indicating their potential therapeutic value that can be used as an option for treating biofilm associated clinical problems caused by A. baumannii.