Serratia liquefaciens
C0085068-Serratia_Liquefaciens_Biofilm_SEM-SPL.jpg
Serratia liquefaciens bacteria


Gram Stain: Serratia is a gram-negative bacterium. This means that it has two membranes: one made of peptidoglycan, and one made of lipopolysaccharide.
Gram Stain Test: To test the gram stain, we flamed the slide with our bacteria to kill it off, and also to make is stick. We then dipped the slide into a container of crystal violet, a stain that, if the bacteria was gram-positive, would have been soaked into the cell wall. After doing so, we put drops of iodine onto the slide, which fixed the color. Alcohol is then applied which would wash away the crystal violet if it were gram-negative. Finally, the slide is dipped into a container of safranin, a stain that colors gram-negative bacteria pink or red.

Methyl Red: For the methyl red test, Serratia liquefaciens turned yellow, which means that the test wass negative. This means that the bacteria produces waste products that are neutral(around 6.0).
Methyl Red Test: Place some bacteria into a test tube of glucose broth and twirl it around. Place the tube into the incubator. Wait 48 hours, and the apply 5 drops of methyl red. If the broth turns red, acidic waste is produced. If it turns yellow or orange, neutral waste is produced.

Motility: Serratia liquefaciens was positive for the motility test, which meant that it is a bacteria that can move.
Motility Test: In a motility test, bacteria is applied to a needle, which then punctures agar in a test tube. After waiting 24 hours, the test tube is studied. Is there is bacteria growing only around the puncture, it is nonmotile, and if the the bacteria grows around the entire test tube, it is motile.

Aerobic: Serratia liquefaciens is facultative, which means that it can live with or without oxygen.
Aerobic Test: In an aerobic test, a petri dish with agar and bacteria is placed inside a glass jar. If after 24 hours there is no growth, then the bacteria is not aerobic, but if there is growth, then it is aerobic.

Hemolysis: Gamma, which means that it does not eat hemoglobin
Hemolysis Test: Swab a blood agar plate with bacteria and wait 24 hours. After waiting, look at the plate. If there is no consumption of blood, it is gamma. If there is some consumption, it is Beta, and if all of the blood around the bacteria has been consumed, it is alpha hemolysis.

Ideal Temperature: 25 degrees Celsius
Temperature Test: Different petri dishes with bacteria and agar are placed at different temperatures. After waiting 24 hours, the petri dishes are taken back to the lab. Whichever petri dish shows the most growth tells you the ideal temperature.
Figura_6_3.jpg
Petri dishes containing Serratia liquefaciens


Bauer-Kirby
Ideal Antibiotic: Tetracycline
Bauer-Kirby Test: Using a sharpie, divide a petri dish into four quadrants and swab it with bacteria. Then, choose four different disks with antibiotics on them. Carefully place one in each of the quadrants, and wait for 24 hours. After the wait, observe the zone of inhibition(the zone around the disk where no bacteria grew). Whichever antibiotic had the largest zone of inhibition is the ideal antibiotic of the four.
Reference:
http://en.wikipedia.org/wiki/Methyl_red_test
http://en.wikipedia.org/wiki/Gram_stain



Max Paris
Serratia2.jpg
The typical rod shaped Serratia bacterium