You are working in a microbiology laboratory that is developing a media type to

Question

You are working in a microbiology laboratory that is developing a media type to types of bacteria. The types of bacteria you are trying to isolate are Gra halophilic, mannitol fermenters that grow in the presence and absence of o media would you use (tube or plate)? What components would you include in t would favor the growth of these types of organisms? List all components below purpose each component serves (selective, differential, indicator, etc.): (3 pts) Biosolt make oram t grouo , 4 components You streak an unknown bacterium on an EMB agar and incubate at room isolate certain xygen. What form of and what 3.) m-positive, motile rDye(to temperature. After 48 4.) hours of incubation, you observe NO growth on the plate. is this unknown bacterium a lactose fermenter? Explain your answer. (2 pts)

Explanation / Answer

3. The criteria for formulating the media type and culture method is as follows:

1. The form of media will be tube culture: This is because the organism that needs to be isolated grows in the presence and absence of oxygen. Only in tube this range of organism can be isolated, especially facultative anaerobes, which means they can grow in the absence of oxygen as well. They may thrive best in decreased oxygen saturation level. Moreover, the organism is motile and tube culture is the method used to test motility.

2. The components needed for the growth of the organism are: halophilic organisms are salt loving organisms: NaCl must be supplemented to make the medium selective for halophilic; mannitol fermenters and so mannitol is supplemented with phenol red to selectively differentiate mannitol fermenting organisms. Phenol red is the indicator that supplements this selective differentiation as the pH of the medium changes because of the mannitol fermentation thus changing the colour of the dye and accommodates easy isolation of the organism under consideration.

The four components are: NaCl, phenol red and mannitol with agar.

4. EMB agar is used for enetric coliform isolation. This is also a differential media for lactose and non-lactose fermentors. The medium contains lactose and so the absence of the growth of these organisms shows that they are not lactose fermentors and will need minimal sugar in the medium. The presence of lactose is not encouraging their growth.

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