Taehyung
If a bacterium is susceptible to the effect of an antibiotic then the bacterium is
sensitive
citrase
are able to utilize the sodium citrate for energy to convert the ammonium phosphate to ammonia
peptonization
bacteria used the amino acids for food which produces ammonia and makes the local pH more alkaline
Kovac's reagent
added to SIM to detect indole and makes the cherry red compound
do not ferment lactose
resistant
Chromagar
helps differentiate many members of the Enterobacteriaceae based on color
Alkaline reverison/conversion
bacteria initially rapidly ferment all the sugars, turning the media yellow
Citirc acid metabolism
agar contains sodium citrate as the only carbon source
Eosin Y and methylene blue
inhibits the growth of Gram-positive bacterial and acts as an indicator that reacts with the acid produced by lactose fermenters
Bacteria are classified as intermediate which means
The bacteria may be gaining resistance to the antibiotic
phenol red
is added to monitor the pH
In addition to sugar fermentation and peptonization, bacteria may reduce sulfate for anaerobic respiration which produces
H2S gas
Positive for citrase activity color
blue
negative: green
EMB
pink- dark purple=
metallic green colonies=
orange-red=
1. coliforms are present
2. rapid lactose fermenters (e.coli) are present
3. no coliforms are present
Gram negative rods that ferment glucose
yellow
acidic pH
Ferrous sulfate
detects H2S gas which turns black
Positive for urease activity
Pink
negative: yellow/orange
MCA
pink=
tan=
1. coliforms present
2. no coliforms are present
Differential media
allows us to determine the presence of enzymatic activity bc some enzymes cause changes in the pH of the media
pink-red
alkaline
Tryptophanase
Coliform bacteria
Gram-negative bacillus, facultative anaerobes, ferment lactose, only live in GI tract of animals
HEA
yellow-pinkish orange=
blue-green=
black=
1. 3 sugars were fermented (likely coliforms)
2. no coliforms are present
3. media id sulfur reduction occurred