Study the antibacterial and antibiofilm activity of Carum copticum against antibiotic-resistant bacteria in planktonic and biofilm forms

Objectives Microbial biofilms has attracted interest in the recent years because they has become the most important cause of nosocomial infections. This study was aimed to examine the antibacterial activities of Carum copticum extracts on the development of microbial biofilms and planktonic form of six pathogenic bacteria. Methods Antimicrobial activity of the crude extracts against the planktonic form of six pathogenic bacteria: Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii and Klebsiella pneumonia was evaluated by using the disc diffusion method. Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) values was determined by macro-broth dilution technique. Anti-biofilm effects were assessed by microtiter plate method. The chemical composition of the herbal extract was identified by GC-MS. Results According to disc diffusion test (MIC and MBC) the ability of C. copticum extracts for inhibition of bacteria in planktonic form was confirmed. The best inhibitory effect of this plant on S. aureus and low inhibitory effect on A. baumannii in planktonic forms were observed. These extracts were efficient to inhibit biofilm structures and concentration of each extract has direct relation with inhibitory effect. The maximum and minimum inhibitory effects of C. copticum methanolic extract on biofilm formation were observed on A. baumannii (98%) and K. pneumoniae (19%) respectively. Conclusion The GC-MS analysis revealed that five active compounds were present in the extract of this plant. Data obtained, suggested that the C. copticum extracts applied as antimicrobial agents against these pathogens particularly in biofilm making.