Abstract

IN VITRO EVALUATION OF ANTIBACTERIAL AND ANTIBIOFILM EFFECT OF GALLIC ACID AGAINST STANDARD STRAINS AND CLINICAL ISOLATES

*Anuya Aparna Rege and Dipti Bhushan Kolte

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Abstract

In era of antimicrobial resistant superbugs the development of not only new antibacterial agents but candidates that are able to target bacteria in biofilms is very much needed and phytochemicals can be an alternative source for such new drugs. Hence, in the present in vitro study, Antibacterial and Antibiofilm potential of Gallic acid was tested against 8 standard strains, namely, Escherichia coli (ATCC- 10148), Klebsiella pneumoniae (ATCC-700603), Pseudomonas aeruginosa (Fisher’s Immuno Type IV), Salmonella typhi (NCTC-786), Bacillus subtilis (ATCC-9372), Enterococcus faecalis (ATCC- 29212), Methicillin Resistant Staphylococcus aureus (MRSA ATCC- 25923), Sarcina lutea (NCTC-2470), Mixed culture of gram Negative organisms, Mixed culture of gram Positive organisms & Mixed culture of all Standard Strains as well as 6 Clinical Isolates namely, Klebsiella aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Proteus vulgaris, Shigella flexneri and Mixed culture of Clinical Isolates using various assays. The study has revealed broad spectrum antibacterial activity inhibiting gram positive as well as gram negative Standard Strains and Antibiofilm effect of Gallic acid against standard bacterial strains as well as their Mixed Cultures. Additionally, current in vitro study has exhibited Antibacterial and Antibiofilm potential of Gallic acid against Clinical Isolates and their Mixed Culture. Moreover, combination Gallic acid + Ciprofloxacin revealed synergistic effect against Biofilms of Standard Strains & Clinical Isolates as well as Biofilms of their respective Mixed cultures. Additionally, Gallic acid has also displayed strong Antioxidant potential through DPPH assay. Thus, Gallic acid exemplifies a possible source of effective, cheap and safe Antibacterial and Antibiofilm agent.

Keywords: Gallic acid, Phytochemicals, Natural Products, Antimicrobial, Antibiofilm.