Abstract

IN VITRO EVALUATION OF ANTIMICROBIAL AND ANTIBIOFILM POTENTIAL OF CITRIC ACID

*Anuya Aparna Rege, Dipti Bhushan Kolte and 3Manasi Ajit Naik

ABSTRACT

Microbial biofilms are problematic in medical, industrial and environmental settings. Citric acid finds broad applications in various industrial sectors such as pharmaceutical, food, chemical and cosmetic industries. Assessment of Antimicrobial and Antibiofilm potential of Citric Acid could be an added advantage for its usage in medical field as well as food industry. Hence, in the present in vitro study, Antimicrobial and Antibiofilm potential of Citric Acid was tested against 8 bacteria, Escherichia coli (Hb-101), Pseudomonas aeruginosa (Fisher’s Immuno Type-IV), Salmonella enterica (NCIM-5256), Salmonella typhi (NCTC-786), Bacillus cereus (ATCC-11778), Bacillus subtilis (ATCC-9372), Enterococcus faecalis (ATCC-29212), Methicillin Resistant Staphylococcus aureus (MRSA ATCC-25923) and their 3 Mixed cultures namely, Mixed Culture-I (Gram Negative Bacteria), Mixed Culture-II (Gram Positive Bacteria) and Mixed Culture-III (Mixture of All Bacteria) as well as 2 fungi Aspergillus niger (ATCC-16404) and Candida albicans (ATCC-10231) using various assays such as MIC, MBC/MFC, Agar Well Diffusion, Time Course study and Antibiofilm assay. This study has revealed broad spectrum antibacterial activity of Citric Acid inhibiting gram positive as well as gram negative bacteria. Additionally, Citric Acid exhibited Antibiofilm potential against mono as well as poly-microbial biofilms. The antibiofilm activity was noted in the order of Mixed Culture-III > P. aeruginosa > Mixed Culture-I > S. typhi > E. coli > B. cereus > E. faecalis > S. enterica > B. subtilis > Mixed Culture-II > MRSA > C. albicans. Furthermore, combination of Citric Acid with standard antibiotics exerted strong synergistic effect against the tested microbes in time course study. Thus, Citric Acid exemplifies a possible source of effective Antibacterial and Antibiofilm agent.

Keywords: Citric Acid, Antimicrobial, Antibiofilm, Natural Products, Biofilm Assay.