Science Journal of Microbiology

August 2013, Volume 2013, ISSN: 2276-626X

Author(s) 2013. This work is distributed under the Creative Commons Attribution 3.0 License.

Short Report


Antibacterial and Synergistic Activity of Different Tea Crude Extracts against Antibiotic Resistant S. Aureus, E. Coli and a Clinical Isolate of S. Typhi

Koech K.R1, Wachira F.N.2, Ngure R.M.3, Wanyoko J.K.4, Bii C.5 and Karori S.M.6

1,4 Tea Research Foundation of Kenya,
P.O. Box 820, Kericho, Kenya.
3,6 Department of Biochemistry and Molecular Biology, Egerton University,
P.O Box 536, Egerton, Kenya.
2 Association for Strengthening Agricultural Research in Eastern and Central Africa, P.O. Box 765 Entebbe, Uganda.
5 Department of Infectious Diseases, Centre for Respiratory Diseases Research,Kenya Medical Research Institute,
P.O. Box 54840-00200 Nairobi, Kenya.

Accepted 5 July, 2013; Available Online 7 August, 2013

doi: 10.7237/sjmb/115


The antibacterial and synergistic effects of black, green, white tea and other specialty teas such as purple tea extracts processed from Kenyan tea germplasm were evaluated and compared with extracts from processed teas of Chinese and Japanese cultivars using disc diffusion method. Methicillin and penicillinase resistant S. aureus ATCC 25923 was most susceptible to the tea extracts; showing the largest inhibition diameters. Extracts from processed black, black tea buds, green, purple coloured leaf (both aerated and non-aerated) and white teas weakly inhibited (p>0.05) E. coli ATCC 25922 and a clinical isolate of S. typhi at a concentration of 1mg/ml after 24 hours. Synergism was observed between all tea extracts and penicillin G against methicillin and penicillinase resistant S. aureus ATTC 25923. This suggests that the concomitant administration of tea and penicillin G may not impair the antibacterial activity of penicillin G.

Keyword:Black tea; green tea; white tea; methicillin and penicillinase resistant S. aureus; E. coli; S. typhi