Cultural Characteristics of E. coli 4.6/5 (118)




Cultural Characteristics of E. coli

Cultural Characteristics of E. coli

1. E. coli is facultative anaerobes.
2. Its optimum growth temperature is 37°C and ranges from 10°C to 40°C.

E. coli on Nutrient Agar (NA)

E. coli on Nutrient Agar (NA)1. They appear large, circular, low convex, grayish, white, moist, smooth and opaque.
2. They are of 2 forms: Smooth (S) form and Rough (R) form.
3. Smooth forms are emulsifiable in saline.
4. Due to repeated sub culture, there is smooth to rough variation (S-R variation).

E. coli on Blood Agar (BA)

E. coli on Blood Agar (BA)1. Colonies are big, circular, gray and moist.
2. Beta (β) hemolytic colonies are formed.

E. coli on MacConkey Agar (MAC)

E. coli on MacConkey Agar (MAC)1. Colonies are circular, moist, smooth and of entire margin.
2. Colonies appear flat and pink.
3. They are lactose fermenting colonies.

E. coli on Mueller Hinton Agar (MHA)

E. coli on Mueller Hinton Agar (MHA)1. Colonies are pale straw colored.

E. coli on Eosin Methylene Blue (EMB) Agar

E. coli on EMB Agar
1. Green Metallic sheen colonies are formed.

E. coli on m-ENDO Agar

E. coli on m-ENDO Agar1. Colonies are green metallic sheen.
2. Metabolise lactose with the production of aldehyde and acid.

E. coli on Violet Red Bile Agar (VRBA)

E. coli on VRB Agar
1. Red colonies (pink to red) are formed.
2. Bluish fluorescence around are seen around colonies under UV.

E. coli on Cystine Lactose Electrolyte-Deficient (CLED) Agar

E. coli on Cystine Lactose Electrolyte-Deficient (CLED) Agar1. They give lactose positive yellow colonies.

E. coli on Liquid Media

E. coli on Liquid Media
1. They show homogenous turbid growth within 12-18 hours.
2. R form agglutinate spontaneously, forming a sediment on the bottom of the test tubes.
3. After prolonged incubation (>72 hrs), pellicle are formed on the surface of liquid media.
4. Heavy deposits are formed which disperses on shaking.

Cultural Characteristics of E. coli

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The Author

Sagar Aryal

Sagar Aryal

I am Sagar Aryal, a passionate Microbiologist and the Scientific Blogger. I did my Master's Degree in Medical Microbiology and currently working as a Lecturer at Department of Microbiology, St. Xavier's College, Kathmandu, Nepal. I am particularly interested in research related to Medical Microbiology and Virology.

11 Comments

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  1. Naveed ali.
    Am Naveed biotechnologist being interested such a work culturing I using this in my current research antimicrobial activities of mono particle

  2. Ajay Kumar Magraiya

    Nice valuable

  3. What media is useful to identify biofilms

  4. i am Aniagu c. tonia, a graduate in microbiology. this is a nice work i think i found it useful in my project research work.

  5. why E. coli gives greyish color colony on blood agar ?

  6. Thanks for your work which is useful for me

  7. I am Salma Mukhtar, I am working on microbial diversity. It is very informative. Thank you for sharing!

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