Fecal Luciferase Measurement for Mouse Infection

Mouse infections were confirmed by luciferase measurement of mouse fecal samples following a previously reported protocol (43 (link)). Briefly, 20 mg of fecal sample was weighed into a 1.5-ml microcentrifuge tube and homogenized in 1 ml of lysis buffer (50 mM Tris-HCl, 10% glycerol, 1% Triton-X, 2 mM dithiothreitol [DTT], 2 mM EDTA) using 10 to 15 glass beads (3 mm) and a vortex mixer for 1 min, followed by clarification of lysate by brief centrifugation. One hundred microliters of lysate was mixed with an equal volume of NanoGlo luciferase buffer, prepared with a 1:50 dilution of the substrate (Promega). Three technical replicates per sample were conducted. Luminescence was measured in a Synergy HT Luminator (BioTek).