Unknown Bacteria Essay
Exercise 5
Introduction:
Many different species of bacteria look similar under the microscope and also have the same staining results (ex. Gram stain). To be able to differentiate between the different species, one can look at the metabolic differences (fermentation), as well as the environmental condition differences (temperature, pH, oxygen requirements). Being able to manipulate these conditions in a controlled environment can help to correctly identify the exact bacteria. Different media can be used to culture and identify bacteria.
Some bacteria require specific nutrients and conditions, while others can make due with whatever the environment has available. Some bacteria lack the enzymes to break down a complex carbon source, while …show more content…
Usually the media is based on a known environmental condition range that they tolerate and most groups can not. An example is Manitol Salts Agar (MSA). This media contains salts that most organisms can’t tolerate due to their osmolity ranges. Microbes that normally exist under these conditions are able to grow. MSA is usually used for Staphylococcal species. Differential media provides chemical compounds that bacteria metabolize differently. The difference is observed by a colony or media color change. This media is often used to differentiate between groups of organisms with the same morphology and biochemical resemblances. Eosin Methylene Blue (EMB) is an example that can be used to differentiate between various Gram (-) rods of the intestinal tract. Escherichia coli and other enteric bacteria are able to ferment. Lactose fermentation results in a colony color change ranging from pink to purple.
Determination of oxygen requirements is a test to determine whether a microbe is an obligate aerobe, anaerobe, or facultative. The culture is put in a melted 5% glucose TSA. As the media cools it solidifies, oxygen is blocked out in the deeper area to create an anaerobic environment. The top and just below the surface has oxygen. The glucose is added to determine if the microbe can ferment glucose. This is shown as a positive if there are cracks or bubbles in the media.
When working with the various media it is
Introduction:
Many different species of bacteria look similar under the microscope and also have the same staining results (ex. Gram stain). To be able to differentiate between the different species, one can look at the metabolic differences (fermentation), as well as the environmental condition differences (temperature, pH, oxygen requirements). Being able to manipulate these conditions in a controlled environment can help to correctly identify the exact bacteria. Different media can be used to culture and identify bacteria.
Some bacteria require specific nutrients and conditions, while others can make due with whatever the environment has available. Some bacteria lack the enzymes to break down a complex carbon source, while …show more content…
Usually the media is based on a known environmental condition range that they tolerate and most groups can not. An example is Manitol Salts Agar (MSA). This media contains salts that most organisms can’t tolerate due to their osmolity ranges. Microbes that normally exist under these conditions are able to grow. MSA is usually used for Staphylococcal species. Differential media provides chemical compounds that bacteria metabolize differently. The difference is observed by a colony or media color change. This media is often used to differentiate between groups of organisms with the same morphology and biochemical resemblances. Eosin Methylene Blue (EMB) is an example that can be used to differentiate between various Gram (-) rods of the intestinal tract. Escherichia coli and other enteric bacteria are able to ferment. Lactose fermentation results in a colony color change ranging from pink to purple.
Determination of oxygen requirements is a test to determine whether a microbe is an obligate aerobe, anaerobe, or facultative. The culture is put in a melted 5% glucose TSA. As the media cools it solidifies, oxygen is blocked out in the deeper area to create an anaerobic environment. The top and just below the surface has oxygen. The glucose is added to determine if the microbe can ferment glucose. This is shown as a positive if there are cracks or bubbles in the media.
When working with the various media it is