The first day of the independent experiment was on October 25, 2016. Mannitol Salt Agar and Phenylethanol Agar are selective media that were used to isolate M. luteus from the environmental samples. Sterile cotton swabs were used to obtain the samples from the skin, arms and dust through wiping the surface of the sample source. A handful of backyard soil was previously diluted and then 2mL of this diluted soil was transferred to a sterile test tube containing 9mL water using a pipette. Four MSA and four PEA plates were used for isolation. PEA plate number 1 was divided into three parts and was used to isolate all of the samples obtained from the skin by rolling the cotton swabs on the surface of the medium. PEA plate number …show more content…
Then, two more tests were conducted. The oxidase test and the catalase test. The oxidase test was done using a sterile cotton swab and an oxidase strip. First, wet a part of the strip using small amount of water and then obtain an inoculum from one of the agar slants using the wooden part of the cotton swab and apply it to the wet part of the strip. Observe for any color change within 15 seconds and interpret the results. The catalase test was performed using the slant that was the source of the inoculum used for the oxidase test. A drop of 3% hydrogen peroxide was added to the said slant and the tube was observed for any …show more content…
SIM deep covers three tests, namely motility, hydrogen sulfide reduction and indole production. Using an inoculating needle, get an inoculum from one of the slants that was transferred last week and then stab the SIM deep medium for about an inch. Incubate the medium at 37˚C for about 48 hours. Citrate test was then conducted. Simmons citrate agar was lightly inoculated using the inoculating loop for this test, however, put pressure while painting the surface of the medium to ensure correct results. Also incubate the agar slant at 37˚C for about 48 hours. The third test that was performed was a fermentation test for sucrose. Using the inoculating loop, transfer an inoculum of the suspected microbe into a phenol red sucrose broth. Mix the inoculum and the broth then incubate it within 48 hours at 37˚C. Urease test was the last biochemical test that was performed this day. A urea tablet was added using the tweezers to a small tube containing one mL of distilled water. After adding the tablet, heavily inoculate the tube with the microbe that was transferred last week. Incubate the small tube at 37˚C for about 48