Tuesday, December 6, 2011

Bacteria Description

Our unknown bacteria, L-25, is of the genus Serratia, and we believe of the genus marcesens. Here are descriptive qualities we have obtained through testing in the lab-

Morphological Characteristics
Cell shape: Bacilli
Size: Small
Spores: none
Gram's Stain: Negative
Motility: Motile
Capsules: none
Special stains: Acid-fast

Cultural Characteristics
Colonies: red
      Nutrient agar: red
      Blood agar:  white, partial lysis
Agar slant: red
Nutrient broth: pink
Gelatin slab: turbid
Oxygen requirements: facultative anaerobe
Optimum temperature: 25 degrees Celsius (but varies, also grows well at 37 degrees Celsius)

Physiological Characteristics
Fermentation
  • Glucose: positive
  • Lactose: partial
  • Sucrose: positive
  • Mannitol: negative
Hydrolysis
  • Gelatin liquefaction: positive
  • Starch: negative
  • Casein: partial
  • Fat: positive
iMViC
  • Indole: positive
  • Methyl Red: negative
  • Voges-Proskauer (acetylmethylcarbinol): positive
  • Citrate Utilization: positive
  • Nitrate Utilization: positive
  • Urease: negative
  • Oxidase: positive
Litmus Milk
  • Acid: no pH change
  • Alkaline: no pH change
  • Coagulation: soft curd formed
All of these characteristics indicate that our unknown bacteria is Serratia marcesens
 

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