Identifying unknown bacteria
... next step is to inoculate a TSI slant and inoculate a Urea Broth tube and let them incubate for 48 hours. Unknown #128 showed no growth on MacConkey so a catalase test needed to be performed which gave a negative result. The next step is to inoculate a blood agar plate and a Mannitol Salt Agar plate. Incubate the cultures for 48 hours and observe results. Results: Data Table of Results Media or Test Used Unknown # 127 Unknown # 128 MacConkey Agar Growth with no fermentation No Growth Catalase Test Not applicable Negative Blood Agar Not applicable Beta Hemolysis Mannitol Salt Not applicable No growth TSI Slants Glucose-acid/gas, lactose (-), sucrose (+) and H2S (+) Not applicable Urea Broth Positive Not applicable Conclusion: Unknown # 127 is the organism Proteus Vulgaris. This is concluded from the information gathered from the cultures and tests. There was growth on the MacConkey, which would indicate a gram-negative rod since MacConkey is a selective media that encourages gram-negative growth. MacConkey is also differential for lactose fermentation, but there was no fermentation reaction. The TSI reactions showed that glucose was acid with gas, lactose was negative and sucrose was positive. The TSI reactions also showed H2S production. The Urea broth reaction was also positive. All of these reactions combined are properties of Proteus Vulgaris. Unknown #128 is the organism Streptococcus Pyogenes. This is concluded from the information gathered from the cultures and tests. There was no growth on the MacConkey, which would indicate gram-positive cocci since MacConkey inhibits gram-positive growth. The Catalase test was negative which indicates a Streptococcus sp. The Mannitol salt showed no growth and the Blood agar showed Beta Hemolysis. All of these...