Unknown report Micro
Identification of Unknown Report
Abstract: The purpose of this lab was to determine the identity of an unknown bacteria slant culture. The unknown was identified using differential tests to determine its metabolic and morphology characteristics. Results from the differential tests indicated that unknown culture 5 is Staphylococcus aureus.
Introduction: The purpose of this lab was to determine the identity of an unknown bacteria slant culture using a series of differential tests. The tests used to identify the unknown bacterial culture included: Gram stain, mannitol salt agar, coagulase tube test, and an antimicrobial susceptibility test. The tests selected were based on the results of a gram stain. Gram staining, the most commonly used differential stain, allows for the fast and easy detection between gram negative and gram positive organisms based on the presence or absence of peptidoglycan. A gram positive organism resists the decolorization process due to a large amount of peptidoglycan and appears a purple color. A gram negative organism is successfully destained, counterstained with safranin and appears reddish-pink. Mannitol salt agar is used to detect an organism’s ability to ferment mannitol, which lowers the pH of the phenol red containing medium. Phenol red is yellow below pH 6.8, red at 7.4-8.4, and pink at pH 8.4 and above. The coagulase test uses rabbit plasma to determine if the organism produces the coagulase enzyme in either the free or bound coagulase forms. Staphylococcus aureus produces a positive test for the coagulase enzyme while other Staphylococcus organisms do not. The last test performed was the test for the resistance to certain antibiotics. The results of the antimicrobial susceptibility test produced different sized zones of inhibition. The size of the zone of inhibition, or lack thereof, to a certain antibiotic determines it’s susceptibility to that antibiotic. Materials and Methods:
Inoculating loop
Abstract: The purpose of this lab was to determine the identity of an unknown bacteria slant culture. The unknown was identified using differential tests to determine its metabolic and morphology characteristics. Results from the differential tests indicated that unknown culture 5 is Staphylococcus aureus.
Introduction: The purpose of this lab was to determine the identity of an unknown bacteria slant culture using a series of differential tests. The tests used to identify the unknown bacterial culture included: Gram stain, mannitol salt agar, coagulase tube test, and an antimicrobial susceptibility test. The tests selected were based on the results of a gram stain. Gram staining, the most commonly used differential stain, allows for the fast and easy detection between gram negative and gram positive organisms based on the presence or absence of peptidoglycan. A gram positive organism resists the decolorization process due to a large amount of peptidoglycan and appears a purple color. A gram negative organism is successfully destained, counterstained with safranin and appears reddish-pink. Mannitol salt agar is used to detect an organism’s ability to ferment mannitol, which lowers the pH of the phenol red containing medium. Phenol red is yellow below pH 6.8, red at 7.4-8.4, and pink at pH 8.4 and above. The coagulase test uses rabbit plasma to determine if the organism produces the coagulase enzyme in either the free or bound coagulase forms. Staphylococcus aureus produces a positive test for the coagulase enzyme while other Staphylococcus organisms do not. The last test performed was the test for the resistance to certain antibiotics. The results of the antimicrobial susceptibility test produced different sized zones of inhibition. The size of the zone of inhibition, or lack thereof, to a certain antibiotic determines it’s susceptibility to that antibiotic. Materials and Methods:
Inoculating loop