One of the leading concerns pertaining to the ferocity of bacterial infection, is the formation of biofilms. Biofilms are aggregations of microbes within an exoskeleton-like structure composed of extracellular polymeric substances and DNA produced by bacterial colonies once they adhere to a surface. They have become an increasingly important research area within the fields of medicine, veterinary medicine, agriculture, and food science. However, most, if not all, research pertaining to them has focused primarily on in vitro studies. While this is an important contribution to a better understanding of biofilms, it is equally as important to understand biofilm in in vivo models. Here, we use the house fly, Musca domestica, as an animal model to identify and characterize biofilms.
This project, to the knowledge of my advisor and myself, attempts something never done before: visualizing biofilm within a live host using staining techniques that can be easily replicated in medical, veterinary, and food science fields. It involved an intense literature search and review, many different technical approaches and failures, and a close working relationship with the microbiology department. Methodology for this project included orally infecting laboratory-reared flies with Serratia marcescens, surgically dissecting the foregut (crop) of the fly, then utilizing PBS, Triton x100, and safranin die to allow for bacterial growth and to close the crop duct, permeate the membrane to allow the die to enter, and then stain the bacterial cells within the crop, respectively.