0
So here is the deal, same use different recipies different results to do the same thing. I'll just post some lecture notes and hope that helps:
- MacConkey's Agar (enterics)
- Selective for gram negative
- Crystal violet and bile salts prevent non-enterics
- Differential for lactose fermentation
- Non-fermenter --> white/clear colonies
- Fermenter--> red/pink colonies
- Eosin Methylene Blue (EMB) (Weakly selective for intestinal pathogens)
- Selective for gram negative
- Eosin and methylene blue inhibit gram positive growth
- Differential for lactose fermentation
- Lactose fermenters produce a green-metallic sheen
- Non-fermenters do not
- NOTE: EMB Agar is not in common use anymore
Wiki User
∙ 14y ago
Wiki User
∙ 8y agoMacConkey agar plate and EMB are both selective for gram negative enteric and coliforms. They have inhibitors to stop growth of gram positive bacteria such as staphylococcus. Both media are also differential for fermenters. MacConkey agar plate contains lactose but EMB also contains sucrose in addition to lactose. Moreover, MacConkey agar plate has bile salt that inhibits gram positive bacteria, but EMB contains aniline dyes (methylene blue and eosin).
Add your answer:
Earn +20 pts
What conclusions may be drawn if no growth appeared on MacConkey agar and emb agar after inoculation of the media and an incubation period?
The conclusion drawn if no growth appeared on MacConkey agar and EMB agar after inoculation of the media and an incubation period could be the bacteria used was possibly a Gram positive non-enteric sample.
What function of emb agar?
function of eosin methylene blue agar (EMB)
Which gram negative bacteria do not grow on macconkey and EMB?
humein ni pata
The agar used most often for throat cultures is the?
Emb agar
Why do some bacteria produce a green metallic sheen on EMB agar?
Because it releases acid and gas when it ferments the lactose on the plate, which causes a color change of the colony. E. coli is a heavy lactose fermenter. This is similar to how when E. coli is grown on MacConkey agar, the colonies turn bright pink compared to a regular lactose fermenter which turns light pink and a non-lactose fermenter which is cream colored. The acid is causing a drop in pH and a reaction with the dye is occurring.
How does yersinia look on nutrient agar EMB agar and MacConkey agar?
Colorless, it doesnt ferment lactose.
What conclusions may be drawn if no growth appeared on MacConkey agar and emb agar after inoculation of the media and an incubation period?
The conclusion drawn if no growth appeared on MacConkey agar and EMB agar after inoculation of the media and an incubation period could be the bacteria used was possibly a Gram positive non-enteric sample.
What conclusion may be drawn if no growth appeared on MacConkey agar and EMB agar after inoculation of the media and an incubation period?
The conclusion drawn if no growth appeared on MacConkey agar and EMB agar after inoculation of the media and an incubation period could be the bacteria used was possibly a Gram positive non-enteric sample.
Which gram positive bacteria grows on macconkey and EMB?
Gram + bacteria do NOT grow on EMB agar, EMB agar inhibits their growth, and is selective for Gram -
Isolation media for actinomycetes?
the most recognized media for isolation of actinomycetes are starch casein and oat meal
Does Mycobacterium phlei grow on EMB agar?
yes it can be grow in EMB agar.
What function of emb agar?
function of eosin methylene blue agar (EMB)
Which gram negative bacteria do not grow on macconkey and EMB?
humein ni pata
The agar used most often for throat cultures is the?
Emb agar
Is EMB agar a defined or undefined medium?
undefined
State the usefulness of EMB agar?
EMB agar or Eosin methylene blue agar is to see which gram negative is lactose fermenters by colonies appearing a purple, black color. It also inhibits the growth of gram positive bacteria.
How do you differentiate between E. coli and salmonella?
E.coliIn stool samples microscopy will show Gram negative rods, with no particular cell arrangement. Then, either MacConkey agar or EMB agar (or both) are inoculated with the stool. On MacConkey agar, deep red colonies are produced as the organism is lactose positive, and fermentation of this sugar will cause the medium's pH to drop, leading to darkening of the medium. Growth on Levine EMB agar produces black colonies with greenish-black metallic sheen. This is diagnosic of E. coli.SalmonellaCulture is microbial growth on or in a nutritional solid or liquid medium; increased numbers of organisms simplify identification. Culture also facilitates testing of antimicrobial susceptibility.Communication with the laboratory is essential. Although most specimens are placed on general purpose media (eg, blood or chocolate agar), some pathogens require inclusion of specific nutrients and inhibitors or other special conditions
