Quantification of bacterial load by CFU counts and by Fluorescent Pixel Counts

CFU counts were performed as previously described [21]. For quantification of bacterial load by Fluorescent Pixel Counts (FPC), fluorescent bacteria were injected in the larvae and imaged using MVX10 Olympus microscope. Fluorescence was quantified by computation using Fiji (ImageJ software) as following: 1/ Background was measured in images of PBS injected larvae and then was subtracted in the fluorescence images, 2/ “make binary” function was run, and 3/ “measure area” function was used to determine the number of fluorescent pixels of the image.