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Unformatted text preview: SELECTIVE AND DIFFERENTIAL MEDIA 1. Selective media—suppress the growth of unwanted bacteria and encourage the growth of a desired microbe or group of microbes. Bismuth sulfite agar--- Salmonella typhi Sabouraud’s dextrose agar—fungus organisms Brilliant green agar--- Salmonella and other gram-negative bacteria 2. Differential media---these media cause colonies of certain microbes to grow with a characteristic appearance. Just by observing growth, the presence of a certain type of microbe can be determined. Streptococcus pyogenes---blood agar (a clear ring forms around colonies) 3. Some media combine the two types and are both selective and differential. Mannitol salt agar--- Staphylococcus aureus Levine's EMB agar McConkey's agar Desoxycholate agar More about selective media for fungi. These media in general contain a higher level of sugar (4%) and a lower pH (3.8 - 5.6) than bacterial media. These conditions discourage growth of (4%) and a lower pH (3....
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- Fall '09
- Bacteria, 4%, Levine, mannitol, Differential Media, McConkey