TITLE - Escherichia coli
SUBTITLE - Characteristics, Identification, Isolation, Significance and Biochemical test
profile for Escherichia coli
Gurleen Kaur
School of Engineering Technology and Applied Science
Centennial College
Microbiology Project 1 (BI-207) - 103
Rochelle Fleming
19 th February,2023
, Characteristics
1. Microscopic Morphology
● Escherichia coli (E. coli) are straight, gram-negative cylindrical rods.
● They are generally 1-1.5μm in diameter and 2.0-6.0μm in length and appear
alone or in pairs. Escherichia coli (E. coli) are from Enterobacteriaceae
family and are Non-motile or motile via peritrichous flagella (Brenner et
al.,2005).
2. Colonial morphology
● The phenotypes of strains grown on agar media are classified as smooth (S) or
rough (R) according to the amount of O antigen polysaccharide polymerized.
● While R forms typically grow as flat, dry, dull, wrinkled colonies (1- 5 mm
diameter) with a blurred edge on agar and agglutinate spontaneously in fluid
media, they have lost their polysaccharide side chains through mutation.
● S forms typically grow on nutrient agar as convex, glistening, moist, grey
colonies (2-3 mm diameter) with a defined edge or in fluid medium as turbid
growth (Brenner et al.,2005).
3. Atmospheric requirements & nutritional requirements
● Strains of E. coli survive and develop throughout the medium range (15–45C).
● E. coli may grow in the mid-range of pH, or between 5.0 and 9.0.
● There are anaerobic biotypes, although most organisms are aerobic and
facultatively anaerobic, that have both a respiratory and a fermentative form of
metabolism.
● oxygenase negative.
● Chemoorganotrophic (Brenner et al.,2005).
SUBTITLE - Characteristics, Identification, Isolation, Significance and Biochemical test
profile for Escherichia coli
Gurleen Kaur
School of Engineering Technology and Applied Science
Centennial College
Microbiology Project 1 (BI-207) - 103
Rochelle Fleming
19 th February,2023
, Characteristics
1. Microscopic Morphology
● Escherichia coli (E. coli) are straight, gram-negative cylindrical rods.
● They are generally 1-1.5μm in diameter and 2.0-6.0μm in length and appear
alone or in pairs. Escherichia coli (E. coli) are from Enterobacteriaceae
family and are Non-motile or motile via peritrichous flagella (Brenner et
al.,2005).
2. Colonial morphology
● The phenotypes of strains grown on agar media are classified as smooth (S) or
rough (R) according to the amount of O antigen polysaccharide polymerized.
● While R forms typically grow as flat, dry, dull, wrinkled colonies (1- 5 mm
diameter) with a blurred edge on agar and agglutinate spontaneously in fluid
media, they have lost their polysaccharide side chains through mutation.
● S forms typically grow on nutrient agar as convex, glistening, moist, grey
colonies (2-3 mm diameter) with a defined edge or in fluid medium as turbid
growth (Brenner et al.,2005).
3. Atmospheric requirements & nutritional requirements
● Strains of E. coli survive and develop throughout the medium range (15–45C).
● E. coli may grow in the mid-range of pH, or between 5.0 and 9.0.
● There are anaerobic biotypes, although most organisms are aerobic and
facultatively anaerobic, that have both a respiratory and a fermentative form of
metabolism.
● oxygenase negative.
● Chemoorganotrophic (Brenner et al.,2005).
