Corynebacterium Flashcards
What is ment by the term palisades when referring to the morphology of Corynebacterium
The term palisades referrs to the bacteria making a row of eachother.
Corynebacterium are the only genus becides acid-fast organisms which display such a unique morphology
WARNING: Corynebacterium also exhibit clumping of bacteria! So they do not have to show this palisades
- What is the species name of the human pathogenic strain of Corynebacterium?
- T or F the above mentioned pathogen has been eliminated completely in developed countries because of routine vaccination programs (DPT)
- Corynebacterium diphtheriae
- False. Routine vaccination programs in developed countries have largely eliminated Corynebacterium diphtheriae however in many developing countries, there may be only 10% of children receiving adequate immunization. As a result, diphtheria causes about 1 million deaths per year.
- Corynebacterium renale is responsible for what diseases in cattle?
- What diseases in sheep and goats?
- Cattle: Pyelonephritis, urinary tract infections, cysitis
- Sheep: Ulcerative posthitis (pizzel rot)
Give the general cell morphology/colony characteristics of Corynebacterium renale
Short, stumpy rods, sometimes thicker at one end, non-hemolytic
- Describe the distribution of C. renale
- What does the distribution tell you about what is nessacary for a cow or sheep to develop disease
- Distribution of C. renale is widely distributed in normal cattle and sheep in the urethra and prepuce.
- This tells you that a cow or sheep must have predisposing factors to develop disease
- List a treatment option when treating for a cow with a C. renale infection
- What about a sheep or goat with a C. renale infection
- Penicillin!
- Surgical intervention or application of topical medication
List the two biovars present in Corynebacterium pseudotuberculosis
Biovar ovis
Biovar equi
List the colony characteristics of Corynebacterium pseudotuberculosis
- Small
- Grayish to yellow to pink
- Fragment easily and can be pushed around the agar surface
- Crumbly (dry) look
- Narrow zone of beta hemolysis
- What would the biochemical results on a urease and a reverse CAMP test show with the organism Corynebacterium pseudotuberculosis
- What two toxins are exibited by C. pseudotuberculosis and what are there primary effects?
- Biochemicals: Urease positive, Reverse CAMP (inhibits staphylococcal beta hemolysin)
- Toxins
- Phospholipase D
- Lethal
- Dermonecrotic (causing necrosis of the skin)
- Weak hemolysin
- Surface lipid
- Toxic for phagocytes
- Phospholipase D
List 2 different modes of transmission of C. pseudotuberculosis?
- Transmission
- Present in the soil (can be ingested, enter wound etc… from here)
- Via wounds (ex. caused by shearing and butting)
- Abraded buccal mucosa or inhalation
- Flies and other insects (mechanical vectors)
- What species would you commonly see the C. pseudotuberculosis Biovar ovis in?
- What does it cause in these species
- Sheep, goats, and cattle
- Caseous lymphadenitis in sheep and goats, and abscesses in cattle
- What species would you commonly see the C. pseudotuberculosis Biovar equi in?
- What does it cause in these species?
- Equids (horses and donkeys) and cattle
- In Equids ulcerative lymphangitis, external abscesses in horses in chest area (pigeon fever) & internal abscesses in the liver, lung, kidneys and spleen, and abscesses in cattle
What tests can you do to diagnose Corynebacterium pseudotuberculosis?
- Based off clinical signs
- ID on culture
-
Synergistic Hemolysis Inhibition test
- Synergizes (makes total effect worst) w/ Rhodococcus equi
- Possibly useful for internal abscesses
How would you treat an zebra with C. pseudotuberculosis
Drainage of abscesses
Penicillin and other antibiotics will not work because they will be unable to get into lesions
Prevention is KEY: quarantine, drain abscesses, vaccination
- List the clinical signs in a Rhodococcus equi infection in a foal?
- Human patient with AIDS?
- Purulent bronchopneumonia, enteritis, and arthritis in foals
- Pulmonary infection
What are the characteristics of colonies of Rhodococcus equi?
- Distinct
- Moist
- Mucoid
- Flowing
- Non-hemolytic
Why is the morphology for the species Rhodococcus equi so difficult to identify?
Bacteria range form large rod – cocci depending on where it is cultured from (Cocci more common for media cultures, Lg. rods more common in liquid media)
As well as, bacteria being heavy encapsulation
- What is the biochemical test result you look for in Rhodococcus equis?
- What is the major antigen associated with R. equis?
- R. equis will have a very strong CAMP postive result extending down to the far end
- Antigen: Virulence-associated protein A (VapA)
- Found in 70-80% of isolates that were disease causing
- What is the typical distribution for the Rhodococcus equi bacteria?
- Your client presents to you a foal with purulent bronchopneumonia, enteritis, and arthritis! When you offer the suggestion of R. equi in your mind you recall that the client mentioned about not having horses in this barn for 10 yrs. Is it possible for the organism to survived for this long?
- Common commensal of the horse and grows in soil
- YES! R. equi are very hardy organisms. They can survive in dust for long periods
List a typically suceptible horse canidate for a Rhodococcus equi infection? (include age range)
- A foal presenting with CID(combined immunodeficiency disease) or some other underlying stresser such as failure of passive transfer (FPT)
- Common in Arabian foals
- Effects foals ~2-5 months of age
In the murine (rat) model of disease the presence of what leads to the killing of Rhodococcus equis?
- The presence or gamma interferon
- Bacterial killing is dependent upon the presence of gamma interferon –> activation of MOs –> production reactive nitrogen & oxygen intermediates –> death of the bacteria
In swine Rhodococcus equi may develop secondary too?
- Tuberculosis
- Organism is frequently isolated from LNs of these sows
What are the treatment options for a foal with Rhodococcus equi?
Erythromycin + rifampin or long-acting macrolides (e.g. Azithromycin)
- Long-acting macrolides tend to work better
Treatment however has to be early enough in the disease in order to be successful
- The organism Corynebacterium bovis is typically found where?
- List a likely disease process of this bacteria
- Tend to be found as commensal organisms on udder
- Mastitis
During a necropsy you identify pyelonephritis on a cow. A student who is working for you asks what possible bacteria can cause this. Based on the bacteria we have covered so far what organism will you choose?
Corynebacterium renale
In the image below of a male goat buck what possible bacteria which we have caused this?
Corynebacterium pseudotuberculosis
