Cultivation of E. coli on BG agar, which is used to differentiate between E. coli and salmonellas.
To avoid getting too many images under the heading “Macromorphology” in VetBact, we have introduced the new heading “Special media” (see e.g. Escherichia coli). Our intention is to use this new heading for images of bacterial colonies cultivated on special media used for isolation and/or identification of the bacterium in question and not for many other bacteria. Under the heading Macromorphology, we will present pictures of bacterial colonies cultivated on “standard media” (e.g. blood agar, purple agar and FA agar). It will take some time to transfer images to this new heading.
Over 300 pictures are included in VetBact (you can see thumb nail images of most of them by chosing Images on the start page). In connection with the latest course in Bacteriology for veterinary students (sep-oct 2011), several new pictures were added in VetBact, for instance:
- Purple agar plates with maltose for Staphylococcus aureus subsp. aureus, S. hyicus and S. pseudintermedius. The metod is important to differentiate S. aureus subsp. aureus from S. pseudintermedius and S. intermedius. All three species are positive for maltose in tube fermentation, but on agar plates, where the conditions are more aerobic, S. pseudintermedius and S. intermedius are negative (or possibly weakly positive).
Colonies of Klebsiella pneumoniae subsp. pneumoniae cultivated on CLED agar.
Karl-Erik Johansson (BVF, SLU) is preparing agar plates with Brucella canis for photography in the safety lab at SVA . Photo: Lennart Melin (SVA).
Samples from a bitch which gave birth to stillborn pups were analyzed during the summer 2011 at the Department of Bacteriology of the National Veterinary Institute (SVA) in Uppsala. Brucellosis caused by Brucella canis was suspected and the isolate was, therefore, sent to the EU Reference Laboratory for Brucellosis in France for further characterization, where Brucella canis was confirmed.
The bitch had been imported from Poland, where it was mated with different male dogs that were suspected of having infected the bitch. Brucellosis is a serious disease, which can be transmitted to humans (a so-called zoonosis) and the infected dog was euthanized to prevent further transmission.
Pictures of the strain of B. canis that caused the first Swedish case of brucellosis on a dog can be found on the page for Brucella canis at VetBact.
Do you recognize this bacterium from its very typical appearence after Gram staining? If not, try the Image Quiz!
Different types of quizzes were added to VetBact during the last year. When the bacteriology course for veterinary students started this autumn, a new kind of quiz - the Image Quiz (IQuiz) – was released. In the IQuiz, you get a very brief description of a case and some images of the bacterium. From these data, it may be possible to identify the bacterium. If not, you can ask for more pictures and also hints.
You can find all quizzes under “Bacteriology Course 2011″ on the start page of VetBact. Then, click on “Image quiz” to check this new type of quiz. Try also the “Disease quiz“, where you will get a continuous compilation of your results. Good Luck!
The other new module of VetBact – the VetBactLab – for experiments in silico, is under evaluation and has not yet been released without a password.
The bacteriology course for the veterinary students, 2008.
On September 20 the bacteriology course starts for the veterinary students. We hope that VetBact will be useful during your studies and we appreciate all kinds of feed-back, which will help us to improve VetBact and its modules. One of the new modules in VetBact is VetBactLab that can be used for “experiments in silico” (dry experiments) and which we hope you will find interesting during your studies and later in your profession.
Feed-back can be given in different ways:
- By leaving a comment on this post (in English or Swedish) in the VetBactBlog. The comment will be published on the Blog if it is relevant.
- By using the contact form, which can be reached from most pages of VetBact (particularly useful if you want to comment or ask a question about a certain bacterial species).
- By leaving a comment on the form, which can be opened when you have finished a case in VetBactLab (particularly useful if you want to comment on the in silico cases).
The VetBactRef group
Gram staining of Klebsiella pneumoniae subsp. pneumoniae, strain CCUG 225. The lengths of the scale bars are equivalent to 5 µm in both A and B. Image: Karl-Erik Johansson (BVF, SLU and Laila Eriksson (SVA).
We have now introduced new images and replaced old ones of Klebsiella pneumoniae subsp. pneumoniae and Klebsiella oxytoca in VetBact. The former species may cause mastitis in cows, urinary tract infections in dogs and pneumonia in calves and foals. The latter species is an opportunist, which may cause diarrhea, bacteremia and mastitis in cattle.
We have also added more information (for instance carbohydrate fermentation schemes) on the bacterial pages for K. pneumoniae subsp. pneumoniae and K. oxytoca.
Escherichia coli, biotype EAggEC, strain O104:H4, cultivated on ESBL agar (Bio Merieux). The red (burgundy) colour of the colonies indicates that this strain has an extended spectrum of betalactamase (ESBL), which means that it is resistant to different penicillins and many cefalosporins. The image is published with permission from Dr. Beutin.
The recent outbreak of VTEC (verotoxin producing E. coli) O104 infections in Europe, leading in some cases to the serious complication HUS (hemolytic uremic syndrome), was first suspected to be caused by consumption of vegetables contaminated by Escherichia coli of the biotype EHEC (enterohaemorragic E. coli). However, it seemed to be a new variant of EHEC, because it was unusually aggressive. It has now been reported from two different European National Reference Laboratories for Escherichia coli (in Rome and Berlin) that this new variant, in addition to the gene for Verotoxin 2, also has the aggR gene, which helps this bacterium to adhere to the host cells. According to the National Reference Laboratories for Escherichia coli at the National Veterinary Institute in Sweden, this E. coli should, therefore, not be regarded as beeing of biotype EHEC, but rather of bioype EAggEC (enteroaggregative E. coli), because it has the aggR gene. Furthermore, this particular E. coli strain was neither found in samples from the vegetables that were suspected to be contaminated, nor from environmental samples although hundreds of samples have been investigated.
More information about biotypes of E. coli, can be found at the website of Dr. Lothar Beutin, at the website of VetBact and in a Ph.D. thesis of Dr. Erik Eriksson at the National Veterinary Institute, Sweden.
Note that it is not allowed to use the image without permission from Dr. Beutin (Natl. Ref. Lab. for E. coli, Federal Institute for Risk Assessment, Diedersdorfer Weg 1, D-12277 Berlin, Germany).
Streptococcus canis on A, purple agar with lactose and B, a SELMA plate.
Six new images of Streptococcus canis has been included in VetBact. Fereshteh Banihashem (Natl. Vet. Inst., Uppsala) has prepared the agar plates for morphological comparisons and Lise-Lotte Fernström (SLU) has performed the Gram staining and the CAMP test.
S. canis may cause mastitis in cows and opportunistic infections in dogs and cats.
The castor oil plant (ricin in Swedish or Ricinus communis in Latin) contains the same type of toxin as Escherichia coli (pathotype EHEC) and Shigella dysenteriae. The photo was taken outside the Academic hospital in Uppsala last year by Karl-Erik Johansson. Date: 2010-10-26.
Today it was written in Svenska Dagbladet (a daily journal in Sweden) that “A new bacterium transmitts ehec”. It is unfortunately a very common mistake among Swedish journalists to confuse the bacterium with the disease. Correctly, it should have been written “A new variant of the bacterium Escherichia coli (E. coli), pathotype EHEC, causes hemorrhagic colitis in humans”. EHEC means enterohemorrhagic E. coli and does not refer to the disease. It would also be correct to refer to the disease as an EHEC infection. As a serious complication of an EHEC infection, HUS (hemolytic uremic syndrome) may occur among young or elderly persons. Cattle may be carriers of Escherichia coli (E. coli), pathotype EHEC. Cattle do not contract the disease, but may transmitt the bacterium by direct contact or via contaminated water and vegetables to humans. More information about enterohemorrhagic E. coli and E. coli of other pathotypes can be found in the introduction to a recent thesis from the Swedish University of Acricultural Sciences by Erik Eriksson.
Veterinarian Annette Backhans nailed her Ph.D. thesis on April 29, 2011 at the Department of Clinical Sciences, SLU.
On May 20, 2011, veterinarian Annette Backhans will defend her thesis entitled: “Wild rodents as carriers of potential pathogens to pigs, chickens and humans, with special emphasis on Brachyspira spp. and Yersinia enterocolitica“.
Annette Backhans is affiliated to the Department of Clinical Sciences at the Swedish University of Agricultural Sciences. Professor Claes Fellström has acted as principal supervisor.
Place: “Ettans lecture room”, KC, Ultuna
Opponent: Dr. Jill Thomson, Scottish Agricultural College, Edinburgh Disease Surveillance Centre, UK.