Indicience of bacteria nad antibacterial activity of selected types of tea

Abstract

The purpose of this study was to determine in vitro antibacterial activity of selected teas (Assam: Indian black tea from Camellia sinensis, Pu-erh: darkpu-erh (shu) from Camellia sinensis, Sencha: Japanese green tea from Camellia sinensis) against five species of pathogenic microorganisms. In our study, we determined the total viable count (TVC), yeasts (Y) andEnterobacteriaceae counts (E). MALDI-TOF MS Biotyper was used for identification of colonies after cultivation. Evaluation of the antimicrobial activity was performed by disc diffusion method, well diffusion method and detection of minimum inhibitory concentration (MIC). For antibacterial activity against Escherichia coli CCM 2024, Yersinia enterocolitica CCM 5671, Klebsiella pneumonie CCM 2318, Staphylococus aureus CCM 2461 and Bacillus thurigiensis CCM19 were detected. The inhibition zones were measured in mm in disc diffusion method and well diffusion method. The MIC of the individual extracts was measured spectrophotometrically. The high number of total viable count was found in Pu-erh tea (2.1 log CFU.g-1) and lowest number was found in Assam tea (0.7 log CFU.g-1). The high number of Enterobacteriacea was found in Pu-erh tea (2.03 log CFU.g-1) and lowest in Assam tea (0 log CFU.g-1). The higher number of yeasts was found in Pu-erh tea (1.83 log CFU.g-1) and lowest in Assam tea (0.3 log CFU.g-1). Mass spectrometry revealed the presence of seven Gram positive bacteria Bacillus cereus, B. mycoides, B. pumilus, Enterococcus durans, Staphylococcus epidermis, S. hominis, S. warneri, four Gram negative bacteriaAcinetobacter junii, Hafnia alvei, Klebsiella pneumoniae, Sphingomonas spp. and two yeast - Candida glabrata, Cryptococcus albidus. The results show that certain tea extracts are particularly active against various pathogenic bacteria. Tea extracts (Sencha, Rooibos, Mate, Assam) were found to have the strongest antibacterial activity against Staphylococcus aureus CCM 2461.