Assessing the Antimicrobial Potential of Bacteriocin-Producing Murine Fecal Bacterial Isolates

Protocol

1. LAB Counting and Bacteriocin Activity

1. Weigh one fecal pellet of each sample in a 1.5 mL tube and add an adequate volume of ice-cold 0.9% NaCl to achieve a 10% (w/v) solution. Use sterile micro pestles for 1.5 mL tubes to homogenize the fecal suspension and prepare ten-fold serial dilutions in ice-cold 0.9% NaCl.
2. Count the total number of LAB cells.
   1. Transfer diluted cells (100 µL) to 4 mL of prewarmed Man Rogosa Sharpe (MRS) soft agar (50 °C, 0.8% agar). Mix by vortexing before pouring the cells onto a solid MRS agar plate (1.5% agar).
   2. Dry the plate by taking the lid off for 5 - 10 min in the st....