Point-Of-Care MIC Biosensor For The Treatment Of Coliform Bovine Mastitis
In this study we attempt to develop a colorimetric microfluidic assay for an in-situ determination of the antibiotic susceptibility of bacteria responsible for mastitis infection in bovine. The study consists of two stages. The first stage focuses in the design and development of a compact microfluidic device capable of self-loading at an efficient time rate to avoid biochemical reactions before it is fully loaded. PDMS material has been implemented to assist with pumping due to its innate capability of absorbing air when degassed. This self-pumping mechanism of the PDMS will force bacteria inoculated liquid samples to flow through microchannels until chambers pre-loaded with different antibiotics are filled. The second stage of the biosensor involves the quantification of bacteria growth in the presence of Ceftiofur hydrochloride, Pirlimycin HCl, Cephapirin sodium and Amoxicillin. Using tetrazolium salts and menadione solutions, non-susceptible bacteria cells to the antibiotics will produce changes in color due to the production of formazan from the succinate-tetrazolium salt reductase system. These biochemicals reactions only take place in the mitochondria of metabolically active cells. If bacteria do not grow, then it is susceptible to the antibiotic and there will be no changes in color. This result is expected due to the absence of mitochondrial enzymes and electron carriers. Stage II experiments will be performed in a 96-well plate where the antibiotics will be pre-loaded and dehydrated in each plate row. Their concentration will be varied in each plate column, and subsequently inoculated liquid samples will be added. The colorimetric assay visual results will then be quantified with the use of a micro plate reader to determine the Minimum Inhibition Concentration (MIC). The goal is to eventually substitute inoculated samples with raw milk. In this way, a farmer can determine which antibiotic will be most suitable for the mastitis infection in a specific bovine with a sample from its milk and the visual reading of changes in color. By using a system with personalized infection treatment, development of antibiotic resistance in livestock may be minimized.