Date of Award

8-2017

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Biology

Thesis Sponsor/Dissertation Chair/Project Chair

Lee H. Lee

Committee Member

John Gaynor

Committee Member

Ann Marie DiLorenzo

Subject(s)

Green tea--Therapeutic use, Plant polyphenols--Health aspects, Epigallocatechin gallate, Antibiotics--Physiological effect

Abstract

The rapidly emerging phenomenon of antibiotic resistance is continually becoming uncontrollable. Over recent years there have been an alarming increase in untreatable multi-drug resistant (MDR) infections that need earnest attention. The mechanisms by which antibiotic resistance is achieved in pathogenic bacteria have been extensively researched and various alternate treatment or intervention strategies have been designed. However, a recently established means of antibiotic resistance observed in bacteria is the formation of a physiological state known as Biofilm. Biofilm are complex adhesive microbial communities known to habitat animate and fomite surfaces. High mortality clinically infectious cases have been associated to the biofilms produced by the pathogens. Multiple factors contribute have been indicated to interplay the biofilm stimulated antibiotic resistance. These established mechanisms are entirely different from canonical antibiotic resistance mechanisms. Thus, biofilm is an elusive problem due to its resilient nature. Biofilm’s increased resistance to multiple antimicrobials indicate the pressing need of alternative natural product therapeutics. Green tea polyphenols (GTP) extracts from the leaves of the herbal plant Camellia sinensis, have been attributed to multiple health-promoting properties such as anti-inflammatory, anti-tumorigenic, antioxidant, antibacterial and antiviral activities. The purified and highly abundant polyphenol extracted from green tea, specifically EGCG have been tested for antibacterial properties and for anti-biofilm activity on certain bacteria. Chemical modification of EGCG has enhanced the green tea beneficial properties. This study focusses on utilizing green tea polyphenols as novel synergistic agents with antibiotics to prevent or control biofilm. Purified and chemically modified lipid soluble green tea polyphenol and prescribed antibiotics at different concentrations were used to study their sole and combinatorial effects on biofilms produced by six different potential pathogenic bacteria. The optimal inhibitory combination concentration was determined for inhibiting the biofilm formation and reducing the preformed biofilm in each organism by more or equal to 90%. Four assays namely Crystal Violet (CV), Colony Forming Unit (CFU), Resazurin and Bacterial Live/Dead, were used to derive the best combination and correlate with each other to a high extent. These results depict the potential of EGCG-S as a synergistic agent with antibiotics and as an antibiofilm agent.

Included in

Biology Commons

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