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Revision as of 03:58, 7 December 2017 by Jljordan77 (talk | contribs) (Habitat Information)
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  • Domain: Bacteria
  • Phylum: Proteobacteria
  • Class: Gammaproteobacteria
  • Order: Enterobacterales
  • Family: Enterobacteriaceae



  • Escherichia coli
  • NCBI Link: Escherichia coli Taxonomy: [1]

Habitat Information


  • Soil Sample Location: Copperfield Park and Greenbelt - 1425 E Yager Ln, Austin, TX 78753
  • Soil Collection Date & time: 9/7/2017 @ 10:00 AM
  • Conditions Present at time of soil collection:
    • No recent rain within past 48 hours
    • Temperature was 71 degrees F
  • Soil sample was retrieved at a depth of roughly 3 inches and about 6-8 inches from creek bed.
  • Description of Area:
    • Pond and creek area
    • Moderate erosion
    • Wildlife present (actually saw a coyote when collecting sample)
    • Area was damp and wet (close to creek bed)
    • Area gets roughly 1/2 day of sunlight everyday

Description and Significance

Antibiotic resistance in E. coli is of particular concern because it is the most common Gram-negative pathogen in humans, the most common cause of urinary tract infections, a common cause of both community and hospital-acquired bacteraemia as well as a cause of diarrhea. In addition, resistant E. coli strains have the ability to transfer antibiotic resistance not only to other strains of E.coli, but also to other bacteria within the gastrointestinal tract and to acquire resistance from other organisms. [2]

  • Colonial Appearance:
    • Shape: Circular
    • Margin: Entire
    • Elevation: Raised
    • Size: Punctiform, small
    • Texture: Smooth
    • Appearance: Shiny
    • Pigmentation: Non-pigmented / colorless
    • Optical Property: Translucent

Describe the appearance (colonial and cellular), possible antimicrobial activity etc. of the organism, and why the organism might be significant.

Genome Structure

  • E. coli has only one circular chromosome
  • Escherichia coli strain S17-13, complete genome
           Genes (total)          :: 5,359
           CDS (total)            :: 5,234
           Genes (coding)         :: 4,987
           CDS (coding)           :: 4,987
           Genes (RNA)            :: 125
           rRNAs                  :: 8, 7, 7 (5S, 16S, 23S)
           complete rRNAs         :: 8, 7, 7 (5S, 16S, 23S)
           tRNAs                  :: 90
           ncRNAs                 :: 13

NCBI Link: E. coli Strain S17-13: [3]

Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Include S Ribosomal sequence that you obtained from PCR and sequencing here.

Cell Structure, Metabolism and Life Cycle

  • Cell Structure: E. Coli is a Gram-negative, facultatively anaerobic, rod-shaped, coliform bacterium. [4]. It also possesses adhesive fimbriae and a cell wall that consists of an outer membrane containing lipopolysaccharides, a periplasmic space with a peptidoglycan layer, and an inner, cytoplasmic membrane. [5]. The integument, the tough outer protective layer, protects the bacterium from other organisms or oppressors.
  • Metabolism: E.coli has fairly simple nutritional requirements. It is a heterotrophic organism, therefor it cannot produce its own food and it must obtain nutrition and energy by taking it from other organisms, most often its host. Carbon is very important to e-coli, and it obtains its carbon from glucose.
  • Reproduction Cycle: E-coli has a very rapid growth cycle; it reproduces by either cell (binary) division (asexual) or through conjugation (sex pilus), the most common reproductive method is asexual reproduction. The time required for a complete cycle varies depending on several factors, however in optimal nutrient conditions, E. Coli can duplicate in about 20 minutes.
  • Life Cycle: In terms of its life cycle, it has a lag phase (growth is slow), log phase (bacteria multiplies exponentially), stationary phase (bacteria growth stabilizes), and death phase.

Interesting features of cell structure; how it gains energy; what important molecules it produces.

Physiology and Pathogenesis

Biochemical characteristics of E. coli:

Characteristic Reactions
Tests E-Coli In class results of organism
Lactose Acid+, gas+ Acid+, gas+
Mannitol Fermentation positive, usually with gas Negative
Methyl-Red Positive Negative
Voges-Proskauer Negative Positive
Catalase Positive Positive
Oxidase Negative Negative
Citrate Negative Negative
Mannitol Positive Negative for fermentation - organism growth
Urea No hydrolysis No hydrolysis
Gelatin Liquefaction Negative Positive
Hemolysis (Alfa/Beta/Gamma) Some Strains show Hemolysis Beta Hemolysis
Crimson DC 14 3C
DNase Negative Positive
Mannitol Positive Negative Fermentation / Organism grew
Bacitracin Negative Negative
Optochin Negative Negative

[[Biochemical characteristics, enzymes made, other characteristics that may be used to identify the organism; contributions to environment (if any). If relevant, how does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms]]








Page authored by Jennifer Jordan and Denise Zamarrippa, student of Prof. Kristine Hollingsworth at Austin Community College.