Gram Positive Bacteria Flashcards
Name three types of canine pyoderma caused by Staphylococcus pseudointermedius.
- Superficial pyoderma
- Pustular pyoderma
- Deep pyoderma
Name and describe four Staphylococcus spp. virulence factors.
- Capsule/ slime layer
- Adhesions
- Toxins & Super antigens
- Protein A
Name the bacterial agent that causes Greasy Pig Disease.
Staphylococcus hyicus
Describe the pathogenesis of staphylococcus hyicus
- Causes exudative non-pruritic dermatitis in young pigs (up to 3 months of age)
Extremely contagious
Name the genus and species causing canine and feline dermatitis.
Staphylococcus pseudointermedius
Using one bacterial example, describe the mechanism of action of superantigens and how they induce an inflammatory response.
Superantigens bind to the MHC class II molecules of antigen-presenting cells and T cells (in a non-antigen-specific manner), which lead to the massive release of cytokines that subsequently bypasses the normal antigen-presenting pathway. This process signals the release of mass inflammatory mediators which cause havoc and make it harder for the immune system to hone in on the specific pathogen.
e.g. Streptococcus canis causing STSS
Name and describe four Streptococcus spp. virulence factors.
- Capsule
- Cell wall proteins (M proteins)
- Adhesions
- Toxins
Name the aetiological agent and describe the treatment and control of equine strangles.
Streptococcus equi subsp. equi
Treatment:
- Compress of lymphadenopathy
Describe the pathogenesis of listeriosis
What bacterial agent is “Silage eye” associated with?
Listeria monocytogenes
What gross & histopathologic lesions might you expect to see in a case of listeriosis?
hint: blood, liver, brain
- Focal hepatitis (white spots on liver)
- Peri-vascular cuffing with micro-abscessation (brain smear - medulla and brain stem)
Name the toxin linked to Greasy Pig Disease.
Exfoliative toxins
Staphylococcus hyicus
Name the bacterial agent causing caseous lymphadenitis in sheep.
Corynebacterium pseudotuberculosis
Name the bacterial agent causing Pizzle Rot in cattle or Ovine Posthitis (Pizzle Rot) in sheep.
Corynebacterium renale
Name the bacterial agent which causes diphtheria in humans
Corynebacterium diphtheriae
Describe the gross findings on necropsy of a sheep with caseous lymphadenitis.
- Encapsulated caseous material found in lymph nodes (characteristic ‘onion ring’ cross section apperance)
- Lung abscessation
- Liver abscessation
List and describe three virrulence factors of Corynebacterium
- Cell wall lipid
- phospholipase D (PLD)
- Serum protease/s
With regard to corynebacterium pseudotuberculosis list and describe the virrulence factors that are required for abscessation in the viscera to occur.
- Phospholipase D (PLD)
- Serum protease/s
If PLD and or/proteases are absent, only local abscesses are formed
List the treatment, control and prevention strategies for Caseous lymphadenitis in sheep.
Treatment:
1. Corynebacterium suseptible to Penecillin’s in vitro, however abscesses limit penetration of the antimicrobial, rendering it reletively ineffective in practice.
2. Surgery - surgical excision/ drainage of caseous lymph nodes. Care must be taken however to ensure bacteria is not then spread in the environment. Treatment is limited as abscesses often reoccur post surgical intervention.
3. Culling of infected sheep.
Control & Prevention:
1. Vaccination - Sheep vaccinated 4-6 weeks prior to sheering (preventing opportunistic infection from knicks when sheering)
2. Culling of infected sheep
3.Imporved sanitation in sheering sheds and on farm in general
4.Reduced stocking densities and close contact between sheep
5.Avoid wet diping where possible
6.Sheer, dip and handle young sheep first (more susceptible to infection)
Name the bacterial agent causing ‘blackleg’
Clostridium chauvoei
Name the bacterial agent that causes Gas gangrene
Clostridium perfringens Type A
Name the bacterial agent that causes ‘Braxy’ in cattle.
Clostridium septicum
Name the bacterial agent causing ‘Blacks disease’.
Clostridium novyi
Name two bacterial agents that may cause polyarthritis in pigs.
Mycoplasma hyorhinus
Mycoplasma Hyosynoviae
Does Mycoplasma hyosynoviae cause polyarthritis in younger or older pigs?
Older, often seen in pigs aged 10-30 weeks old.
How would you treat a case of discospondylysis caused by Aspergillus fumigatus?
- Treatment of disseminated Aspergillosis fumigatus is complicated, time-consuming, and can often be expensive.
- Antifungal treatment is available (for example, fluconazole), however, requires long-term use (months – years).
- Pain medication (NSAIDs or opioids)
- Restricted exercise and physical activity and bed/ cage rest
- Euthanasia is a treatment option in severe cases (neurological signs and no resolution following antifungal & supportive treatment).
How would you treat a case of discospondylysis caused by Staphylococcus pseudointermedius?
- S. pseudointermedius is an opportunistic infection, therefore investigate the potential underlying cause of primary infection (surgical wound, surgical bone implant wound).
- Deep infection (as it has disseminated to the bone), therefore long and high dose AMs are required to treat the infection.
- Perform culture and sensitivity to determine if it is a MRSP and determine which antimicrobial is most likely to be effective.
- If not MRSP, systemic antibiotics likely – Cephalosporins, beta-lactamase resistant penicillins (long course –> 3-12 weeks)
- Pain medication (NSAIDs or opioids)
- Restricted exercise and physical activity and bed/cage rest
- Euthanasia is a treatment option in severe cases (neurological signs and no resolution following AM & supportive treatment)
What is the aetiological agent that caused Lumpy wool (sheep) & rain rot/ rain scald (horses)?
Dermatophilis congolensis
Name the aetiological agent causing Johne’s disease?
Mycobacterium avium subsp paratuberculosis
Name the atieological agent causing ringworm in horses.
Trichophyton equinum
Name the atieological agent causing ringworm in cattle.
*Thricophyton verrucosum *
Name the agent causing swine dysentry
Brachyspira hyodysenteriae
