Simple and Rapid Method for Screening Antimicrobial Activities of Bifidobacterium Species of Human Isolates

The objective of this research was to develop a rapid procedure for the screening antimicrobial activities of Bifidobacterium species of human isolates. A bifidobacteria selective medium BIM‐25 agar was modified by adding of 0.5 g/L cysteine‐hydrochloride, 1.5 g/L lithium chloride, 1.0 g/L beef extract, and 5 mL/L Tween 20. This medium was inoculated (45C) with diluted fecal material from 5 subjects and overlaid into 0.1% Tween 20 BHI agar plates. Plates were incubated in anaerobic chamber at 37C for 48 h. Plates were then inverted to allow the two layers of agar to fall into the petri lid. BHI soft agar (0.45%) containing Micrococcus luteus (as indicator) was overlaid onto the other layers in the petri dish. Plates were incubated at 37C overnight and zone of growth inhibition was observed. This method is simple and rapid whereas the original method for screening of antimicrobial activities of bifidobacteria is a more time consuming and cumbersome procedure.