Selected and Differential Media

Define Selective Media Differential Media Enriched Media

Blood Agar Plate (BAP) Differential Enriched Use  Growth  Hemolysis Alpha Beta Gamma

C-CNA Selective Differential Results  Gram (+) Colistin Naldixic acid  Blood Hemolysis

MSA Selective Differential Results  Halotolerant (7.5% NaCl)  CH2O: Mannitol  pH phenol red Fermentation  Acid  Yellow

MAC Selective Differential Results  Gram (-) CV Bile Salts  Lactose  pH indicator Neutral red indicator  Ferment = pink/red  No acid = colorless

EMB Selective Differential Results  Gram (-) Eosin dye MB dye  Lactose Some acid = pink Large acid = green No acid = colorless

Set Up One plate for each group Label quadrants as lab book indicates for each plate Cultures on cart Anaerobic Gas Pack  BAP  C-CNA All others aerobic 37°C

BAP results Sheep blood enriched Growth most all microbes Fastidious Differential  GP Hemolysins  Hemolysis types Gamma Alpha Beta

Hemolysis No hemolysis

C-CNA results Selective  Growth GP Colistin Nalidixic acid Differential  Hemolysis

MSA results Selective 7.5% NaCl Staphylococcus sp Differential Mannitol fermentation phenol red  yellow

MAC results Selective: GN  CV  Bile Salts Differential  Lactose fermentation  NF = colorless  Coliforms Neutral red  pink

EMB results Selective: GN  Dyes Eosin MB Differential  Lactose fermentation  NF = colorless  Acid production Small = pink Large = metallic green