Gram negative bacillus Flashcards
(22 cards)
when you have a gram negative rod, what is the first test you do in diagnostics?
oxidase test
If the oxidase test was positive, what tests will you do next?
Growth on chocolate agar and pseudomonas chrome agar if it is a straight rod.
If the rod has a distinct helical or curved shape, growth on MAC agar.
if an oxidase positive straight rod grows on chocolate agar, what bacteria do we have?
Haemophilus sp.
if an oxidase positive straight rod grows green/blue on nutrient agar and grows on pseudomonas chrome agar, what bacteria do we have?
Pseudomonas sp,
- most likely P. aeruginosa
if we have a gram negative, oxidase positive curved or helical bacillus, what agar do we grow it on?
MacConkey agar
If we have no growth on a macConkey agar for a helical or curved oxidase positive bacillus, what test do we do next?
urease test
If we have growth on a MacConkey agar plate with NO lactose fermentation of a helical or curved oxidase positive bacillus, what bacteria do we have?
Vibrio sp.
if we have a helical or curved, oxidase +ve bacillus, no growth on a MAC agar plate and a positive urease test, what bacteria do we have?
Helicobacter sp
if we have a helical or curved, oxidase +ve bacillus, no growth on a MAC agar plate and a negative urease test, what bacteria do we have?
campylobacter sp.
If we have a gram negative oxidase negative bacillus, what is the next test we do?
culture on a MacConkey agar plate
If we have a gram negative oxidase negative bacillus, that ferments lactose what test do we do next?
Eosin-methylene Blue agar, Bile esculine and Nutrient agar.
if we have green, metallic growth of an oxidase negative bacillus on an EMB plate, what bacteria do we have?
Escherichia Coli
if we have pink colonies on an EMB plate of an oxidase negative bacillus, what bacteria do we have?
Klebsiella sp
Enterobacter sp
If an oxidase negative, lactose fermenting gram negative bacillus turns agar brown on a bile-Esculin plate, what bacteria do we have?
Klebsiella sp.
If an oxidase negative, lactose fermenting gram negative bacillus has mucoid colonies on a nutrient agar plate, what bacteria do we have?
Klebsiella sp.
If we have an oxidase negative result and the bacteria ferments lactose on a MAC agar, what three options of bacteria could it be?
E. coli
Klebsiella sp
Enterobacter sp.
if we have growth but no lactose fermentation on a MAC agar plate of an oxidase negative bacillus, what tests do we do next?
Bile esculine agar, XLD agar and Nutrient agar.
if we have growth but no lactose fermentation on a MAC agar plate of an oxidase negative bacillus, and turns a bile esculin agar plate brown, what bacteria do we have?
Serratia sp
if we have growth but no lactose fermentation on a MAC agar plate of an oxidase negative bacillus, and grows red colonies on an XLD agar plate, what bacteria do we have?
Shigella sp
if we have growth but no lactose fermentation on a MAC agar plate of an oxidase negative bacillus, and grows colonies with a dark center on an XLD agar plate, what bacteria do we have?
salmonella sp
if we have growth but no lactose fermentation on a MAC agar plate of an oxidase negative bacillus, and grows red colonies on a nutrient agar plate, what bacteria do we have?
Serratia sp
if we have growth but no lactose fermentation on a MAC agar plate of an oxidase negative bacillus, and swarms on a nutrient agar plate, what bacteria do we have?
Proteus sp
