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

Abstract

Source: Bäuerl, C., et al. A Method to Assess Bacteriocin Effects on the Gut Microbiota of Mice. J. Vis. Exp. (2017).

This video demonstrates the detection of bacteriocin-producing lactic acid bacteria derived from mouse fecal matter. The assay determines the antimicrobial activity of bacteriocin on specific bacterial strains.

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....

Results

Figure 1: Detection of Bacteriocin Production in LAB Recovered from Feces by a Three-layer Protocol (as described in the procedure)

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Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Plastic Petri dish	Thermo Scientific	101VR20
Brain-Heart-Infusion broth	Conda	1400
European Bacteriological Agar	Pronadisa	1800
Agarose D1 Low EEO	Pronadisa	8010
1x TAE buffer	Thermo Scientific	15558042
MRS broth	Difco	288130
PBS tablets	Sigma	P4417-100TAB
Scale	Mettler Toledo	PB602-S