Selective and Differential Media
EMB Selective for Gram negative E.coli has green metallic sheen No growth of Gram pos Staph aureus
MSA: Selective and Differential Selective because of salt: only Staph can grow Differential because S. aureus ferments mannitol sugar (turns it yellow) but Staph epidermidis does not ferment mannitol. Note there is no growth or fermentation from M. luteus.
MSA with Staph aureus
Mitis Salivarius Agar
Mitis Salivarius Agar
Mitis Salivarius Agar
BLOOD AGAR: Enrichment media, and Differential
Fish Eye Colonies of Enterobacter on blood agar
MacConkey’s Agar: Selective and Differential Selective because Gram pos are inhibited by the bile salts. Differential because it has lactose. Gram negs that ferment lactose turn yellow.
Antibiotic Sensitivity
Antibiotic Sensitivity Organism is resistant to the antibiotic Organism is susceptible to the antibiotic
Antibiotic Sensitivity: Check zone diameters on given table Organism has intermediate resistance to the antibiotic Organism is resistant to the antibiotic Organism is susceptible to the antibiotic
Coagulase Test: Differentiates S. Aureus from S epidermidis Positive: S. aureus Negative: S. epidermidis