Salmonella Typhi: Introduction, Identification Features, Keynotes, and Salmonella Footages

Introduction of Salmonella Typhi

Salmonella Typhi is a member of the family, Enterobacteriaceae and it is a Gram-negative bacillus, non-sporing, non-encapsulated, aerobic, or facultative anaerobe of size 2 to 4 × 0.6 µm that causes enteric fever (typhoid fever) and food poisoning or gastroenteritis.

Salmonella Typhi growth on MacConkey, Gram stained image, biochemical tests and Salmonella Typhi and S.  Paratyphi on XLD agar
Fig. 1. Salmonella Typhi growth on MacConkey medium, 2. Gram-stained image, 3. biochemical tests in TSI, SIM, citrate, and urea agar, and 4. Salmonella Typhi (black) and Salmonella Paratyphi on XLD agar

Biochemical Tests of Salmonella Typhi

Basic FeaturesProperties
1. Gram StainingGram-Negative Rods (GNRs)
2. SporeNon-Sporing
3. CapsuleNegative
4. MotilityPositive
5. PigmentNegative
6. Growth in potassium cyanide (KCN) mediumNegative
7. Catalase testPositive
8. Oxidase testNegative
9. Nitrate reduction testPositive
10. MR (Methyl Red) testPositive
11. VP (Voges- Proskauer) assayNegative
12. OF (Oxidative-Fermentative) testFermentative/Facultative anaerobe
13. Gas Negative
14. H2S productionPositive
15. Indole formationNegative
16. Urease/ urea hydrolysis testNegative
17. Citrate/ citrate utilizationNegative
18. DNase testNegative
19. Glucose fermentationPositive 
20. Maltose fermentationPositive
21. Lactose fermentationNegative
22. Sucrose fermentationNegative
23. Xylose fermentationPositive 
24. Mannitol fermentationPositive
25. Acetate UtilizationNegative
26. ONPG (β-galactosidase)Negative
27. Phenylalanine Deaminase (PDA)/PPA TestNegative
28. Lipase testNegative
29. Esculin Hydrolysis testNegative
30. Lysine Decarboxylase TestPositive
31. Ornithine Decarboxylase TestNegative
32. Arginine Dihydrolase TestNegative
Table: Properties of Salmonella Typhi

Keynotes on Salmonella

  • The mode of transmission of S. Typhi is the faeco-oral route.
  • The infective dose of typhoid is 10 bacilli through ingestion.
  • Most strains of Salmonella are motile except Salmonella gallinarum and S. pullorum.
  • Antigens of Salmonella are o antigen (somatic),H antigen (flagellar), Vi antigen and K antigen (capsular antigens), F antigen (fimbrial), M antigen and R antigen (in S R mutation due to the loss of O antigens).
  • Salmonella Paratyphi causes paratyphoid.
  • Salmonella Typhi differs from Salmonella Paratyphi in TSI reactions on the basis of H2S production (S. Typhi) and gas formation (S. paratyphi).

Salmonella Footages

Gram-negative rods of S. Typhi in Gram staining of culture

Gram negative rods of Salmonella Typhi in Gram staining of culture
Fig. Gram-negative rods of Salmonella Typhi in Gram staining of culture at a magnification of 1000X

S. Typhi Growth on BHI Broth (Blood Culture Bottle)

Salmonella Typhi Growth on BHI Broth (Blood Culture Bottle)
Fig. S. Typhi Growth on BHI Broth (Blood Culture Bottle)

Salmonella Typhi Colony Morphology on Nutrient Agar

Salmonella Typhi Colony Morphology on Nutrient Agar
Fig. S. Typhi Colony Morphology on Nutrient Agar

Salmonella Typhi Colony Characteristics on Blood Agar

Salmonella Typhi Colony Characteristics on Blood Agar
Fig. S. Typhi Colony Characteristics on Blood Agar

Salmonella non-lactose fermenter colony on MacConkey medium

Salmonella non-lactose fermenter colony on MacConkey medium
Fig. Salmonella non-lactose fermenter colony on MacConkey medium

Salmonella Typhi (black colony) and Salmonella Paratyphi colony on XLD agar expo

Salmonella Typhi (black colony) and Salmonella Paratyphi colony on XLD agar expo
Fig. S. Typhi (black colony) and Salmonella Paratyphi colony on XLD agar expo

Salmonella Typhi biochemical reactions in TSI, SIM, citrate, and urea agar

Salmonella Typhi biochemical reactions in TSI, SIM, citrate and urea agar
Fig. S. Typhi biochemical reactions in TSI, SIM, urea, and citrate agar

Salmonella Paratyphi biochemical reactions in TSI, SIM, urea agar, and citrate medium

Salmonella Paratyphi biochemical reactions in TSI, SIM, urea agar, and citrate medium
Fig. Salmonella Paratyphi biochemical reactions in TSI, SIM, urea agar, and citrate medium

S. Typhi Details

Salmonella Typhi Growth on Nutrient agar, Blood agar, MacConkey medium, BHI broth and biochemical assays in TSI, SIM, Citrate and urea agar
Fig. S. Typhi Growth on Nutrient agar, Blood agar, MacConkey medium, BHI broth and biochemical assays in TSI, SIM, Citrate, and urea agar

Further Readings

  • Cowan and Steel’s, manual for the identification of medical bacteria
  • Topley and Wilson’s microbiology and microbial infection Topley and Wilson’s microbiology and microbial infection – Bacteriology-2-10th Edn.
  • Manual of Clinical Microbiology   -Patrick R. Murray -8th Edn.
  • Bailey and Scott’s  Diagnostic Microbiology -13th Edn.
  •  Mackie & Mc Cartney  Practical Medical Microbiology- 14th  Edn.
  • Diagnostic Microbiology -Connie R. Mahon & George Manuselis
  • Koneman Color Atlas and Textbook of Diagnostic Microbiology-6th  Edn.
  • Jawetz Melnick and Adelberg’s Medical Microbiology- 25th Edn.
  • Lippincott’s –Illustrated- review-Microbiology-3rd Edn.
  •  Mandell’s Infectious Disease-7th Edn.
  • Bergey’s Manual of Systemic Bacteriology – 2nd  Edn.
  • Text Book of Microbiology -Anantanarayan & Paniker-9th Edn.

66 thoughts on “Salmonella Typhi: Introduction, Identification Features, Keynotes, and Salmonella Footages”

  1. You could definitely see your expertise in the work you write. The world hopes for more passionate writers like you who aren’t afraid to say how they believe. Always follow your heart.

    Reply
  2. I am now not sure where you’re getting your information, but great topic. I needs to spend a while studying more or working out more. Thanks for magnificent information I was in search of this info for my mission.

    Reply
  3. There are some fascinating points in time on this article however I don’t know if I see all of them middle to heart. There’s some validity but I will take maintain opinion until I look into it further. Good article , thanks and we would like more! Added to FeedBurner as well

    Reply
  4. Once I originally commented I clicked the -Notify me when new feedback are added- checkbox and now each time a comment is added I get four emails with the identical comment. Is there any method you can take away me from that service? Thanks!

    Reply
  5. Hi there, just became alert to your blog through Google, and found that it’s truly informative. I am going to watch out for brussels. I’ll appreciate if you continue this in future. Numerous people will be benefited from your writing. Cheers!

    Reply
  6. Very good blog you have here but I was curious if you knew of any message boards that cover the same topics talked about here? I’d really love to be a part of community where I can get responses from other knowledgeable people that share the same interest. If you have any suggestions, please let me know. Thank you!

    Reply
  7. Hey, I think your website might be having browser compatibility issues. When I look at your website in Firefox, it looks fine but when opening in Internet Explorer, it has some overlapping. I just wanted to give you a quick heads up! Other then that, wonderful blog!

    Reply
  8. There are certainly a number of particulars like that to take into consideration. That may be a great level to carry up. I supply the thoughts above as normal inspiration but clearly there are questions like the one you bring up where an important factor might be working in trustworthy good faith. I don?t know if greatest practices have emerged round issues like that, however I am sure that your job is clearly recognized as a good game. Both boys and girls really feel the impact of just a moment’s pleasure, for the rest of their lives.

    Reply
  9. An impressive share, I just given this onto a colleague who was doing just a little analysis on this. And he in fact bought me breakfast as a result of I discovered it for him.. smile. So let me reword that: Thnx for the deal with! But yeah Thnkx for spending the time to discuss this, I really feel strongly about it and love reading extra on this topic. If possible, as you develop into experience, would you thoughts updating your weblog with extra details? It is extremely helpful for me. Large thumb up for this blog submit!

    Reply
  10. Wonderful items from you, man. I have be aware your stuff previous to and you are just too great. I really like what you’ve bought right here, certainly like what you are saying and the way in which through which you assert it. You’re making it enjoyable and you continue to take care of to stay it sensible. I can’t wait to read far more from you. That is really a wonderful website.

    Reply
  11. Greetings from Ohio! I’m bored to tears at work so I decided to check out your website on my iphone during lunch break. I really like the information you present here and can’t wait to take a look when I get home. I’m amazed at how fast your blog loaded on my phone .. I’m not even using WIFI, just 3G .. Anyways, amazing site!

    Reply
  12. Hi there, just turned into aware of your blog through Google, and found that it is truly informative. I am going to watch out for brussels. I’ll appreciate if you happen to continue this in future. Numerous people can be benefited out of your writing. Cheers!

    Reply
  13. Thanks for all your hard work on this website. My mother take interest in managing internet research and it’s easy to understand why. Most people know all relating to the lively mode you offer powerful guides on your blog and strongly encourage contribution from website visitors on that concern so my child is now becoming educated a lot of things. Enjoy the rest of the year. You are always conducting a dazzling job.

    Reply
  14. Your style is reall unique comparred to otther people I hasve read stuhff from.
    Than youu for posting when you have the opportunity, Guess I will
    just book mmark ths site.

    Reply
  15. Did you write the article yourself or you hired someone to do it?
    I was wondering because I am a site owner too and struggle
    with writing new content all the time. Someone told me to use
    AI to do create articles which I am kinda considering because the output is almost written by
    human. Here is the sample content they sent me – https://sites.google.com/view/best-ai-content-writing-tools/home

    Let me know if you think I should go ahead and use
    AI.

    Reply
  16. I’m impressed, I need to say. Really hardly ever do I encounter a weblog that’s each educative and entertaining, and let me tell you, you may have hit the nail on the head. Your idea is excellent; the problem is something that not sufficient persons are talking intelligently about. I’m very completely satisfied that I stumbled throughout this in my seek for something relating to this.

    Reply
  17. Throughout this awesome scheme of things you receive an A+ for effort. Where exactly you lost us was first on the specifics. You know, they say, the devil is in the details… And it couldn’t be more true in this article. Having said that, allow me reveal to you just what exactly did work. Your writing is actually rather engaging and that is possibly the reason why I am making the effort in order to opine. I do not make it a regular habit of doing that. Second, whilst I can easily notice a jumps in logic you come up with, I am not really convinced of exactly how you appear to unite the points that make the conclusion. For now I will, no doubt yield to your position however trust in the near future you actually connect the facts much better.

    Reply
  18. Hi there this is kind of 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 skills so I wanted to get advice from someone with experience. Any help would be enormously appreciated!

    Reply
  19. Hi there! Someone in my Myspace group shared this site with us so I came to check it out.

    I’m definitely enjoying the information. I’m book-marking
    and will be tweeting this to my followers! Fantastic blog and fantastic style and
    design.

    Reply
  20. Greetings! Very useful advice in this particular post! It’s the little changes that make the biggest changes. Many thanks for sharing!

    Reply
  21. Pretty nice post. I just stumbled upon your blog and wanted to mention that I’ve truly enjoyed browsing your blog posts. After all I will be subscribing to your feed and I’m hoping you write once more very soon!

    Reply
  22. What’s Happening i’m new to this, I stumbled upon this I have found It positively useful and it has helped me out loads. I’m hoping to give a contribution & help different users like its helped me. Good job.

    Reply
  23. Very nice post. I just stumbled upon your blog and wanted to say that I ave really enjoyed surfing around your blog posts. After all I will be subscribing to your feed and I hope you write again soon!

    Reply

Leave a Comment