Introduction of E. coli
Table of Contents
Escherichia coli is a member of the family, Enterobacteriaceae and it is a Gram-negative, aerobe, and facultative anaerobic, rod-shaped bacterium. The optimal temperature for growth is 36-37°C with most strains growing over the range 18-44 °C. It is a commensal that is found inhabiting the lower intestine of our body. A small proportion of E. coli strains are pathogenic. The harmless strains produce vitamin K and prevent the colonization of the intestine by pathogenic bacteria. It is classified into serotypes based on cell wall (O), capsular (K), fimbria (F), and flagellar (H) antigens. e.g. E. coli O157:H7
Pathogenic strains
- Enterotoxigenic Escherichia coli (ETEC)
- Enteropathogenic E.coli (EPEC )
- Enteroinvasive E. coli (EIEC)
- Enterohaemorrhagic E. coli (EHEC)
- Enteroaggregative E. coli ((EAEC))
Identification Features of E. coli
| Basic Features | Properties |
| 1. Gram Staining | Gram-Negative Rods (GNRs) |
| 2. Spore | Non-Sporing |
| 3. Capsule | Capsulated (many isolates) |
| 4. Motility | Motile |
| 5. Pigment | Negative |
| 6. Growth in potassium cyanide (KCN) medium | Negative |
| 7. Catalase test | Positive |
| 8. Oxidase test | Negative |
| 9. Nitrate reduction test | Positive |
| 10. MR (Methyl Red) test | Positive |
| 11. VP (Voges- Proskauer) assay | Negative |
| 12. OF (Oxidative-Fermentative) test | Fermentative |
| 13. Gas from Glucose | Positive |
| 14. H2S production | Negative |
| 15. Indole formation | Positive |
| 16. Urease/ urea hydrolysis test | Negative |
| 17. Citrate/ citrate utilization | Negative |
| 18. DNase test | Negative |
| 19. Glucose fermentation | Positive |
| 20. Maltose fermentation | Positive |
| 21. Lactose fermentation | Positive |
| 22. Sucrose fermentation | Negative |
| 23. Xylose fermentation | Positive |
| 24. Mannitol fermentation | Variable |
| 25. Acetate Utilization | Positive |
| 26. ONPG (β-galactosidase) | Positive |
| 27. Phenylalanine Deaminase (PDA)/PPA Test | Negative |
| 28. Lipase test | Negative |
| 29. Esculin Hydrolysis test | Variable |
| 30. Lysine Decarboxylase Test | Positive |
| 31. Ornithine Decarboxylase Test | Variable |
| 32. Arginine Dihydrolase Test | Negative |
Escherichia coli Footages
Gram negative rods (GNRs) of Escherichia coli in Gram staining of culture
E. coli growth on MacConkey medium
E. coli colony morphology on blood agar
E. coli Colony Characteristics on Chocolate Agar
Indole positive Escherichia coli in MIU medium
Indole positive Escherichia coli in peptone water
Escherichia coli metallic green sheen on eosin methylene blue (EMB) agar demonstration
Sorbitol MacConkey Agar (SMAC) expressing sorbitol fermenting colony of Escherichia coli and the non-sorbitol fermenting colony of Escherichia coli
Escherichia coli on CLED agar
Further Readings
- https://www.sciencedirect.com/science/article/pii/B97801241584670000
- https://universe84a.com/sorbitol-macconkey-agar-smac-introduction/
- Cowan & Steel’s Manual for identification of Medical Bacteria. Editors: G.I. Barron & R.K. Felthani, 3rd ed 1993, Publisher Cambridge University Press.
- Bailey & Scott’s Diagnostic Microbiology. Editors: Bettey A. Forbes, Daniel F. Sahm & Alice S. Weissfeld, 12th ed 2007, Publisher Elsevier.
- Mackie and Mc Cartney Practical Medical Microbiology. Editors: J.G. Colle, A.G. Fraser, B.P. Marmion, A. Simmous, 4th ed, Publisher Churchill Living Stone, New York, Melborne, Sans Franscisco 1996.
- Textbook of Diagnostic Microbiology. Editors: Connie R. Mahon, Donald G. Lehman & George Manuselis, 3rd edition2007, Publisher Elsevier.
Hey there, You’ve performed a great job. I will certainly digg it and individually suggest to my friends. I’m confident they will be benefited from this web site.
I am extremely inspired with your writing abilities and also with the layout in your blog. Is this a paid topic or did you modify it yourself? Either way stay up the excellent high quality writing, it is rare to see a nice weblog like this one nowadays..
I am glad to be one of many visitants on this outstanding internet site (:, regards for putting up.
I have been checking out a few of your posts and i can state pretty nice stuff. I will make sure to bookmark your website.
I like this web site so much, saved to bookmarks.
I reckon something truly special in this site.
Undeniably believe that that you said. Your favourite reason appeared to be at the net the simplest thing to remember of. I say to you, I certainly get irked even as people think about concerns that they plainly don’t recognize about. You managed to hit the nail upon the top and outlined out the whole thing without having side-effects , folks could take a signal. Will probably be back to get more. Thank you
Hello! I just would like to give a huge thumbs up for the great info you have here on this post. I will be coming back to your blog for more soon.
I’ve been surfing online more than 3 hours today, but I never found any interesting article like yours. It is pretty price enough for me. Personally, if all web owners and bloggers made just right content as you probably did, the net shall be much more helpful than ever before. “I thank God for my handicaps, for through them, I have found myself, my work and my God.” by Hellen Keller.
Great blog here! Also your website loads up fast! What host are you using? Can I get your affiliate link to your host? I wish my website loaded up as quickly as yours lol
I am curious to find out what blog platform you happen to be utilizing? I’m experiencing some small security problems with my latest site and I’d like to find something more secure. Do you have any solutions?
Appreciate it for this howling post, I am glad I found this website on yahoo.
I would like to thnkx for the efforts you have put in writing this blog. I am hoping the same high-grade blog post from you in the upcoming as well. In fact your creative writing abilities has inspired me to get my own blog now. Really the blogging is spreading its wings quickly. Your write up is a good example of it.
I’m truly enjoying the design and layout of your blog. It’s a very easy on the eyes which makes it much more enjoyable for me to come here and visit more often. Did you hire out a developer to create your theme? Outstanding work!
You are a very bright person!
You could certainly see your skills within the work you write. The sector hopes for even more passionate writers like you who are not afraid to mention how they believe. At all times go after your heart. “We are near waking when we dream we are dreaming.” by Friedrich von Hardenberg Novalis.
Wohh precisely what I was searching for, thankyou for posting.
You are my intake, I have few blogs and infrequently run out from post :). “Yet do I fear thy nature It is too full o’ the milk of human kindness.” by William Shakespeare.
Your place is valueble for me. Thanks!…
Great write-up, I’m normal visitor of one’s site, maintain up the nice operate, and It’s going to be a regular visitor for a long time.
Appreciating the dedication you put into your site and detailed information you present. It’s nice to come across a blog every once in a while that isn’t the same unwanted rehashed material. Excellent read! I’ve saved your site and I’m adding your RSS feeds to my Google account.
Greetings I am so glad I found your web site, I really found you by accident, while I was browsing on Aol for something else, Nonetheless I am here now and would just like to say thanks a lot for a marvelous post and a all round enjoyable blog (I also love the theme/design), I don’t have time to browse it all at the moment but I have book-marked it and also added your RSS feeds, so when I have time I will be back to read a lot more, Please do keep up the fantastic job.
You made some respectable points there. I regarded on the web for the problem and found most people will go along with together with your website.
Your place is valueble for me. Thanks!…
Howdy! Do you know if they make any plugins to help with SEO? I’m trying to get my blog to rank for some targeted keywords but I’m not seeing very good success. If you know of any please share. Appreciate it!
It is truly a nice and helpful piece of info. I’m happy that you simply shared this useful information with us. Please stay us informed like this. Thanks for sharing.
I used to be very pleased to seek out this net-site.I wanted to thanks on your time for this excellent read!! I positively enjoying each little little bit of it and I’ve you bookmarked to take a look at new stuff you weblog post.
Pretty nice post. I just stumbled upon your weblog and wished to say that I have really enjoyed browsing your weblog posts. In any case I’ll be subscribing in your feed and I am hoping you write again very soon!
Great line up. We will be linking to this great article on our site. Keep up the good writing.
It’s really a cool and helpful piece of information. I am satisfied that you just shared this useful info with us. Please stay us up to date like this. Thank you for sharing.
Thanks for your thoughts. One thing I have noticed is the fact banks as well as financial institutions know the spending habits of consumers plus understand that a lot of people max out and about their own credit cards around the trips. They wisely take advantage of this fact and begin flooding a person’s inbox plus snail-mail box using hundreds of no interest APR card offers immediately after the holiday season concludes. Knowing that if you are like 98 of the American open public, you’ll rush at the chance to consolidate personal credit card debt and shift balances for 0 APR credit cards.
Hi there, I enjoy reading all of your post.
I like to write a little comment to support you.
Thanks for your personal marvelous posting! I quite enjoyed reading it, you happen to be a great author.I will be sure to bookmark your blog and will come back in the future. I want to encourage you to definitely continue your great work, have a nice day!
I am not sure where you’re getting your information, but good topic. I needs to spend some time learning much more or understanding more. Thanks for wonderful information I was looking for this information for my mission.
I am grateful for your post. I would really like to say that the tariff of car insurance differs from one insurance policy to another, due to the fact there are so many different facets which give rise to the overall cost. By way of example, the brand name of the car or truck will have an enormous bearing on the cost. A reliable older family vehicle will have a more affordable premium than just a flashy racecar.
This article is a breath of fresh air! The author’s unique perspective and perceptive analysis have made this a truly engrossing read. I’m thankful for the effort he has put into producing such an informative and mind-stimulating piece. Thank you, author, for providing your knowledge and igniting meaningful discussions through your brilliant writing!
Good post. I learn one thing more difficult on completely different blogs everyday. It’s going to at all times be stimulating to read content from other writers and observe a bit something from their store. I?d favor to make use of some with the content material on my blog whether you don?t mind. Natually I?ll give you a hyperlink on your internet blog. Thanks for sharing.
Thanks for the something totally new you have exposed in your post. One thing I’d prefer to touch upon is that FSBO relationships are built after a while. By bringing out yourself to the owners the first weekend their FSBO will be announced, prior to masses start out calling on Monday, you build a good relationship. By giving them methods, educational products, free accounts, and forms, you become the ally. By using a personal affinity for them and also their problem, you develop a solid relationship that, many times, pays off when the owners decide to go with a realtor they know and also trust – preferably you actually.
Hey There. I discovered your weblog using msn. This is a very neatly written article. I?ll be sure to bookmark it and return to learn extra of your useful info. Thank you for the post. I?ll definitely return.
I just could not depart your web site before suggesting that I really enjoyed the standard information a person provide for your visitors? Is gonna be back often to check up on new posts
Something more important is that while looking for a good on-line electronics shop, look for web shops that are consistently updated, trying to keep up-to-date with the latest products, the best deals, and helpful information on services. This will ensure that you are getting through a shop that stays on top of the competition and give you things to make intelligent, well-informed electronics buys. Thanks for the vital tips I have really learned from the blog.
Wonderful post but I was wondering if you could write a litte more on this subject? I’d be very grateful if you could elaborate a little bit further. Bless you!
I’ve observed that in the world the present day, video games would be the latest phenomenon with children of all ages. There are occassions when it may be unattainable to drag young kids away from the activities. If you want the very best of both worlds, there are several educational activities for kids. Interesting post.
Hello this is kinda of off topic but I was wondering if blogs use WYSIWYG editors or if you have to manually code with HTML. I’m starting a blog soon but have no coding expertise so I wanted to get advice from someone with experience. Any help would be enormously appreciated!
you are truly a excellent webmaster. The site loading speed is incredible. It kind of feels that you’re doing any distinctive trick. Also, The contents are masterwork. you’ve done a great process on this subject!
Good post. I be taught one thing more challenging on totally different blogs everyday. It’ll all the time be stimulating to read content from other writers and observe just a little something from their store. I?d favor to use some with the content on my weblog whether you don?t mind. Natually I?ll provide you with a hyperlink in your web blog. Thanks for sharing.
Have you ever thought about adding a little bit more than just your articles? I mean, what you say is fundamental and everything. However imagine if you added some great photos or video clips to give your posts more, “pop”! Your content is excellent but with pics and video clips, this site could certainly be one of the greatest in its niche. Awesome blog!
Thanks for another informative web site. Where else could I get that kind of information written in such a perfect way? I have a project that I am just now working on, and I’ve been on the look out for such info.
Valuable information. Lucky me I found your web site by accident, and I am shocked why this accident didn’t happened earlier! I bookmarked it.
I think this is among the most significant info for me. And i’m happy reading your article. But should remark on few general things, The site style is ideal, the articles is truly excellent : D. Excellent task, cheers
I have noticed that online degree is getting preferred because accomplishing your college degree online has developed into a popular alternative for many people. Quite a few people have not necessarily had a possibility to attend an established college or university although seek the increased earning potential and career advancement that a Bachelor Degree offers. Still people might have a degree in one training but want to pursue anything they now have an interest in.
Hmm is anyone else encountering problems with the images on this blog loading? I’m trying to determine if its a problem on my end or if it’s the blog. Any feedback would be greatly appreciated.
Thanks for expressing your ideas in this article. The other element is that any time a problem develops with a laptop or computer motherboard, folks should not consider the risk regarding repairing this themselves because if it is not done properly it can lead to irreparable damage to an entire laptop. In most cases, it is safe just to approach the dealer of the laptop for the repair of its motherboard. They have got technicians that have an knowledge in dealing with laptop motherboard difficulties and can make right prognosis and undertake repairs.
What an insightful and well-researched article! The author’s meticulousness and capability to present complicated ideas in a digestible manner is truly commendable. I’m thoroughly captivated by the breadth of knowledge showcased in this piece. Thank you, author, for sharing your wisdom with us. This article has been a game-changer!
very nice publish, i certainly love this website, keep on it
Thanks for the marvelous posting! I truly enjoyed reading it, you might be a great author.I will make sure to bookmark your blog and will eventually come back in the future. I want to encourage that you continue your great writing, have a nice holiday weekend!
I really like what you guys tend to be up too. This type of clever work and coverage! Keep up the wonderful works guys I’ve added you guys to our blogroll.
Thanks for your publication. One other thing is that often individual states have their particular laws which affect people, which makes it very difficult for the the legislature to come up with a fresh set of recommendations concerning home foreclosure on people. The problem is that each state features own legislation which may work in an unwanted manner when it comes to foreclosure insurance plans.
I?m not sure where you’re getting your info, but great topic. I needs to spend some time learning much more or understanding more. Thanks for fantastic information I was looking for this information for my mission.
Thanks for your short article. I would love to say that the health insurance agent also utilizes the benefit of the actual coordinators of any group insurance policy. The health insurance agent is given a list of benefits sought by someone or a group coordinator. Such a broker may is try to find individuals or coordinators which best match up those desires. Then he presents his referrals and if all sides agree, the broker formulates binding agreement between the two parties.
WONDERFUL Post.thanks for share..more wait .. ?
This will be a terrific blog, would you be involved in doing an interview regarding how you developed it? If so e-mail me!
you’re really a good webmaster. The web site loading speed is incredible. It seems that you’re doing any unique trick. In addition, The contents are masterwork. you’ve done a wonderful job on this topic!