Although bacteria is microscopic in size, it is largely important in the healthcare field, environmental work, food preparation, as well as many other industries. In particular, it is essential that healthcare workers be able to identify the species of bacteria invading a human reservoir in order to prescribe the correct antibiotic that will kill that species. For the purpose of bacteria identification, numerous tests have been devised to find out the exact species in question. However, because new strains continue to emerge, it is of the utmost importance that microbiologists and microbiology students understand the nature of each bacterial species and how that species creates and maintains its complex communities. Of equal …show more content…
This was done using an inoculating needle and aseptically transferring the bacteria into a slant of Simmon's citrate agar by stabbing the needle into the butt of the agar, then streaking it across the top of the agar as the needle was pulled out. The tube was then placed in the 37 degrees Celsius incubator for 48 hours, observed for a blue color, then placed back in the incubator for another 5 days and observed again.
The sixth and seventh tests performed was the fermentation of sucrose and arabinose. This was performed by aseptically inoculating a tube of phenol red sucrose broth, and a tube of phenol red arabinose broth with the unknown culture and incubating at 37 degrees Celsius for 48 hours. After incubation, the two tubes were examined for color change.
The eighth test was to find out if the bacteria in question had flagella. The motility test was performed by aseptically inoculating the unknown bacteria into a tube of TSA broth and allowing it to incubate for 24 hours at 37 degrees Celsius. After the TSA broth culture had incubated, it was used to inoculate a tube of motility medium S to the third. The inoculated motility medium was then incubated at 37 degrees Celsius for another 24 hours and observed for red streaks radiating from the stab …show more content…
If the bacterium produces butanediol as an end product, it undergoes butanediol fermentation. Because Unknown 1 tested negative for this test, it must ferment glucose by mixed acid fermentation. All bacteria that could complete butanediol fermentation were eliminated from possible species of bacteria.
Certain species of bacteria will produce hydrogen sulfide from the amino acid cysteine. This unknown species of bacteria tested positive for hydrogen sulfide production, indicating it is capable of catabolizing cysteine. This is important in certain environments when cysteine can be used as an energy source for respiration. Any bacteria that could not use cysteine as an energy source were eliminated.
The indole production test was used to find out if this species of bacteria could hydrolyze tryptophan into indole, pyruvic adic and ammonia. The red layer at the top of the test tube showed a positive test for the unknown species of bacteria indicating that it possess the enzyme tryptophanase. All bacterial species that did not contain this enzyme were