Microbiology Unknown 1 was found in a nearby pond that was created by an earthquake. Some of the various methods introduced and practiced in class were applied in identifying the microbe. Procedures were followed as stated in the index of the Virtual Unknown Software.
The MSA will select for organisms such as Staphylococcus species which can live in areas of high salt concentration plate on the left in the picture below. This is in contrast to Streptococcus species, whose growth is selected against by this high salt agar plate on the right in the picture below.
The differential ingredient in MSA is the sugar mannitol. Organisms capable of using mannitol as a food source will produce acidic byproducts of fermentation that will lower the pH of the media.
The acidity of the media will cause the pH indicator, phenol red, to turn yellow. Staphylococcus aureus is capable of fermenting mannitol left side of left plate while Staphylococcus epidermidis is not Gram negative unknown lab report side of left plate.
This is a test commonly used when trying to identify Gram-negative enteric bacteria, all of which are glucose fermenters but only some of which produce gas. Like MSA, this medium also contains the pH indicator, phenol red. If an organism is capable of fermenting the sugar glucose, then acidic byproducts are formed and the pH indicator turns yellow.
Escherichia coli is capable of fermenting glucose as are Proteus mirabilis far right and Shigella dysenteriae far left. Pseudomonas aeruginosa center is a nonfermenter. The end product of glycolysis is pyruvate. Organisms that are capable of converting pyruvate to formic acid and formic acid to H2 g and CO2 gvia the action of the enzyme formic hydrogen lyase, emit gas.
This gas is trapped in the Durham tube and appears as a bubble at the top of the tube. Escherichia coli and Proteus mirabilis far right are both gas producers.
Notice that Shigella dysenteriae far left ferments glucose but does not produce gas. The degree of hemolysis by these hemolysins is helpful in differentiating members of the genera Staphylococcus, Streptococcus and Enterococcus. Beta-hemolysis is complete hemolysis.
It is characterized by a clear transparent zone surrounding the colonies. Staphylococcus aureus, Streptococcus pyogenes and Streptococcus agalactiae are b-hemolytic the picture on the left below shows the beta-hemolysis of S. Partial hemolysis is termed alpha-hemolysis.
Colonies typically are surrounded by a green, opaque zone. Streptococcus pneumoniae and Streptococcus mitis are a-hemolytic the picture on the right below shows the a-hemolysis of S. If no hemolysis occurs, this is termed gamma-hemolysis. There are no notable zones around the colonies.
Staphylococcus epidermidis is gamma-hemolytic. What type of hemolysis is seen on each one of the following plates?
TOP Streak-stab technique Often when inoculating a BAP to observe hemoloysis patterns, investigators will also stab several times through the agar using an inoculating loop.
This stab allows for the detection of streptolysin O, a specific hemolysin produced by Streptococcus pyogenes. This hemolysin is inactivated by O2 and is only seen subsurface in an anaerobic environment around the stab mark.
Note the oval-shaped areas of clearing around the stab marks in the picture below; these are caused by streptolysin O.Each culture contained one unknown Gram positive bacteria and one unknown Gram negative bacteria. The purpose of the experiment was for each student to “identify the genus and species of [these two unknown bacteria]” by “utiliz[ing] the techniques and information learned in previous exercises” (p.
).5/5(3). their OU report. 1. Receive your unknown tube and immediately record its code label in your unknown number and the name of your lab instructor.
3. Introduction: This section briefly describes the nature of the problem and what No key is provided for Gram negative cocci, so if your species belongs to this group, you need to make the key.
The gram negative in my original tube (unknown #) would not grow or even show up in the nutrient agar. So I was given a tube that was a gram negative bacteria by Professor Snaric, from that moment on, every went by swiftly as I tried to find out my unknown (ALT 5).
UNKNOWN LAB REPORT. Unknown number The Gram test concluded that the bacterium was a Gram negative rod. This narrowed down the unknown to 5 possible answers: Escherichia coli, Klebesiella pneumoniae, Enterobacter aerogenes, Proteus vulgaris, and Pseudomonas aeruginesa.
The first biochemical test performed was a Simmons Citrate, and. The unknown gram-negative bacteria is Enterobacter aerogenes. The other bacteria which was microscopically viewed as gram positive was missing in the incubator, another tube of sample was derived from the lab professor.
LAB REPORT OF MICROBIOLOGY 3. Uploaded by. Akbar Haqi. are several objective why we should do this experiments such as knowledge of the differences between gram positive and gram negative bacteria, develop the lab skill, and be more familiar with gram staining procedure.
There are also several material that we use in this experiment such as.