35113 Study Guide - Final Guide: Pill Testing, Reagent, Methyl Red
Document Summary
Knowing what is in the agar will help you understand why it is used and how it works. Carbohydrate, peptone, yeast extract, ph indicator to the detect changes in the media. This is in combination with a selective agent to stop the growth of unwanted bacteria. General purpose: nutrient agar, tsa agar and bhia grow most bacteria. Selective agar: maconkey agar, mannitol salt agar, pemba agar, tsc agar and bp agar. Differential agar: blood agar, maconkey, msa agar, pemba agar, bp agar. The bp agar is for the isolation of s. aureus from food specimens. This agar is used for the presumptive identification of s. aureus. A coagulase test would be needed to confirm s. aureus. Black colonies indicate tellurite reduction, opaqueness indicate lipase activity, halo clearing indicate proteolytic activity that re presumptive for s. aureus. Mannitol causing a drop in ph that causes the. Macconkey is both a differential and selective agar.
