Green tea and epigallocatechin-3-gallate are bactericidal against Bacillus anthracis

Bacillus anthracis, the etiological agent of anthrax, is listed as a category A biothreat agent by the United States Centers for Disease Control and Prevention. The virulence of the organism is due to expression of two exotoxins and capsule, which interfere with host cellular signaling, alter host water homeostasis and inhibit phagocytosis of the pathogen, respectively. Concerns regarding the past and possible future use of B. anthracis as a bioterrorism agent have resulted in an impetus to develop more effective protective measures and therapeutics. In this study, green tea was found to inhibit the in vitro growth of B. anthracis. Epigallocatechin-3-gallate (EGCG), a compound found abundantly in green tea, was shown to be responsible for this activity. EGCG was bactericidal against both the attenuated B. anthracis ANR and the virulent encapsulated B. anthracis Ames strain. This study highlights the antimicrobial activity of green tea and EGCG against anthrax and suggests the need for further investigation of EGCG as a therapeutic candidate against B. anthracis.