More complex organisms, including all plants and animals, whose cells have. The best staining techniques to use is the Gram stain or the Acid- fast stain due to the fact that they both will provide a lot of information in detail regarding the bacteria being studied. Staphylococcus aureus and Staphylococcal Disease. Therefore, different methods of staining exist to be able not only to see but also to differentiate bacteria. A few little-known and poorly understood bacteria have different shapes, such as the star-shaped stella and axe-shaped labrys. Objective: To identify the bacterial unknowns in a mixed culture by morphological and biochemical methods. The bacteria were studied based on their physical characteristics and recorded.
Starch agar is a simple nutritive medium with starch added. The biochemical tests performed were chosen based on the identification table that was given from the lab instructor. These microorganisms are important to humans because they play a role in the ecology of life, by decomposing wastes, both natural and man-made, such as creating nitrogen fertilizer at the root zones of certain crops. The capsule stain detects if your unknown bacterium has a capsule which is a secondary structure made of polysaccharides surrounding the bacteria to confer it additional resistance, nutrient storage, adhesion and waste dumping. Identification of bacteria is important because they are not only useful but potentially dangerous as well. It is estimated that some 500,000 patients in American hospitals contract a staphylococcal infection each year.
Cocci and bacilli are further classified by the linkages they form after cell division. The methods used for The colonies were smooth, translucent, and had a white brownish color. Cooked meat medium contains heart tissues, meat containing cysteine residues. Alpha-amylase 1,4 alpha D-Glucan-glucanohydrolase acts upon large polymers of starch at internal bonds and cleaves them to short glucose polymers. This was seen in my gram stain and streak plate test results. This black line or tube indicates a positive H 2S reaction; absence of a black precipitate indicates a negative reaction.
An obligate aerobe requires oxygen for growth. The medium turns red if the test is positive for E. Anaerobic bacteria will grow everywhere in the medium, facultative anaerobes will grow everywhere with a preference for the top of the medium and aerobic bacteria will grow only at the top of the medium where there is still oxygen present. The purpose of doing so ensures that we have pure cultures of the unknown to be used in further testing and not a mixed culture. Amyloglucosidase works on the shorter polymers and splits off single glucose sugars. This narrowed it down to both of the Bacillus species.
Three different carbohydrates are used to determine whether the organism can ferment a sugar as well as if a gas is produced during heterofermentation. Some bacteria have the capability to convert the salts of organic acids, for example, Sodium citrate to alkaline carbonates. For healthcare providers it is very important to be aware of what organisms are pathogenic and cause a disease and, therefore, to find an appropriate treatment. The second is used as a stock sub-culture, should it be necessary to repeat any of the tests. A gram stain reaction test is used to differentiate between two bacterial species. Materials and Methods: The unknown number 123 handed out by the Professor on March 20, 2014 contained both a gram positive bacteria and a gram negative bacteria.
Nitrate reaction occurs only under anaerobic conditions Fig 8. At this point, both bacteria were successfully isolated and plated on stock nutrient agar plates. Words: 1178 - Pages: 5. Another test is whether or not your unknown has an hemolytic reaction. If your bacteria grows it is either an anaerobe or a facultative anaerobe. The following test is the coagulase test which shows if bacteria are capable of coagulating oxolated plasma. More prominent and visible bacteria.
First, the bacteria mix inside the Unknown 109 tube was streaked across a nutrient agar plate using the quadrant streak technique. This narrow view has certainly something to do with the obsolete taxonomy, which, as we have seen, is restricted to pathogenic micro-organisms or to those few others that are responsible for alimentary fermentation. Using a series of biochemical tests and characteristics, unknown 22 was concluded to be Pseudomonas aeruginosa. Prokaryotes move by means of propeller-like flagella unique to bacteria or by special fibrils that produce a gliding form of motility. The second step to your identification is to put your unknown on a microscope slide and observe the morphology of your cell.
The streak plate was then incubated at 37 degrees Celsius for 48 hours. The bacteria showed to metabolize sugars but did not produce any gaseous byproducts. This test is mostly used on streptococci species: it differentiates non pathogenic streptococci from pathogenic streptococci. Indole will react with Kovac's reagent to produce a cherry red complex, which indicates a positive indole test. This is indicated by the change in colour of the medium from orange red to deep red. All those stains give you additional data on your unknown cell and brings you closer to knowing which species it belongs to.
Since the original Unknown test tube was not allowing the gram negative to grow, an Alternative 4 tube was assigned as well. It builds resistance against a lot of antibiotics and even chemotherapeutic agents. After the Gram stain was completed, the bacteria were streaked on a Mannitol-Salt Agar plate and a Catalase test was performed. Environmental and Industrial Use of Bacillus Subtilis. The small amount of acid produced in the slant of the tube during glucose fermentation oxidizes rapidly, causing the medium to remain orange red or revert to an alkaline pH.
This test had a positive reaction meaning the reduction to nitrites occurred. Knowing the differences of each is vital to treat a patient correctly. The process of identification was achieved by utilizing procedures learnt during the semester. Unknown bacteria determined to be Alcaligenes faecalis because of its morphological, physiological and metabolic properties. We talked about cell morphology earlier but it is true that bacterial cells are often colorless and therefore you wouldn't be able to see anything under the microscope. You can also test for inulin fermentation.