Bacterial skin disease Flashcards
Outline the classes of bacteria that can be cultured from the skin?
Resident - can replicate on the skin and can persist.
Nomad - organisms that can colonise and reproduce on the skin for short times.
Transient - can not replicate so stay for a short time.
Pathogens - organisms that become established and can proliferate on the skin surface and deeper that are deleterious to normal physiology of the skin.
Give examples of transient and resident bacteria found on dogs?
Resident - skin
- Micrococcus spp.
- Coagulase -ve Staphylococci
- Staphylococcus epidermidis
- Staphylococcus xylosus
- β-haemolytic streptococci
- Clostridium spp.
- Propionbacterium acnes
- Acinetobacter spp.
- Gram -ve aerobes.
Resident - hair
- Bacillus spp
- Micrococcus spp
- Gram –ve aerobes (proximal)
- Staphylococcus pseudintermedius
Resident - hair follicle
- Micrococcus spp
- Propionbacterium acnes
- Staphylococcus pseudintermedius
- Bacillus spp
Transient - skin
- Staphylococcus pseudintermedius
- E. coli
- Proteus mirabilis
- Cornyebacterium spp.
- Bacillus spp.
- Pseudomonas spp.
Give examples of transient and resident bacteria found on cats?
Resident - skin
- Micrococcus spp.
- Coagulase -ve staphylococci
- Staphylococcus simulans
- β-haemolytic streptococci
- Staohylococcus aureus
- Staphylococcus pseudintermedius
- Acinetobacter spp.
Transient - skin
- β-haemolytic streptococci
- E. coli
- Proteus mirabilis
- Pseudomonas spp.
- Alcaligenes spp.
- Bacillus spp.
- Staphylococcus spp
What innate and specific defences exist in the skin?
Innate
- Sebaceous glands have an antibacterial effect
- squames shed on the top (if skin is insulted get increase in squame production why animals with skin disease have an excessive production of squames)
Specific
- APCs in the dermis
Diagnostic techniques in dermatology?
- Dermatological signs
- Examination of coats with lens.
- Flea combing/wet paper
- Acetate tape preparation
- Cytology – aspirate/impression smear
- Trichogram
- Skin scrapings
- Wood’s lamp examination
- Fungal culture
- McKenzie toothbrush culture
- Bacterial culture and susceptibility testing
- Skin biopsies – histology +/- culture
What is the difference between primary and secondary infections?
Primary infection: infection on skin that is otherwise normal.
Secondary infection: (more common) result of cutaneous, immunological or metabolic abnormality.
Clinical signs of cat bite abscess?
- Acute onset
- Pyrexia
- Painful
- Fluctuant swelling
- Often head or back end
- Scab/2 puncture marks
- Inappetance and depression
What is an abscess?
- A collection of pus formed by tissue destruction in an inflamed area of a localized infection.
- A defensive reaction of the tissue to prevent the spread of infectious material.
- An inflammatory response
- Attracting white blood cells
- Increasing the regional blood flow.
- A wall is formed by the adjacent healthy cells in an attempt to keep the pus from infecting neighbouring structures.
- However this barrier can prevent immune cells from attacking bacteria in the pus.
- Abscesses are differentiated from emphysemas, which are accumulations of pus in a pre-existing rather than a newly formed anatomical cavity.
How may a rabbit jaw abscess be treated?
- Large jaw abscess
- Exteriorise and remove as much of abscess as possible
- Remaining abscess capsule is sutured to skin (marsupilised) to allow topical therapy on remaining abscess tissue
How should abscesses be managed?
- Sedate/GA?
- Administer analgesic
- Administer systemic antibacterial?? Do just as well if you lance and drain
- Clip and prep
- Local?
- Lance – scalpel blade – drain/pull off scab
- Lavage
- Leave open
- If large – insert a drain/marsupialise
- Continue systemic antibacterials??
Recognise the 3 types of canine pyoderma?
Surface pyoderma
- Secondary bacterial colonisation of skin surface.
- Acute moist dermatitis (“wet eczema”)
- Skin fold pyoderma (”intertrigo”)
Superficial pyoderma
- Infection involves skin and hair follicle epithelium.
- Impetigo
- Superficial bacterial folliculitis
- Pyotraumatic folliculitis
- Mucocutaneneous pyoderma
Deep pyoderma
- Infection involves the dermis and subcutaneous tissue.
- Cellulitis,
- Furunculosis
- Acral lick furnculosis
What can be seen in this image?
Canine surface pyoderma (CSP)
Acute moist dermatitis
- IS USUALLY A SECONDARY CONDITION
- Look for a primary pruritic condition
- Otitis externa
- Anal gland impaction
- Fleas/other ectoparasites
- ??Function of hair coat
- ??Breed predosposition – Golden retreiver
Where can Intertrigo – skin fold dermatitis often be found?
- Facial fold
- Vulval fold
- Lip fold
- Tail fold
How does acute moist dermatitis manifest?
Acute moist dermatitis (come on quickly and intensely pruritic)
- Hot spot
- Wet eczema
- Pyotraumatic dermatitis
How can canine surface pyoderma be managed?
- Treat the primary disease
- Skin folds – surgical?
- Skin fold owner can wipe daily with antibacterial wipe to prevent.
- AMD –is there a primary cause you need to be cognisant of fleas/ears/AGs?
- Treat the bacterial infection
- Anti-Staphylococcal antibacterial
- Treat the inflammation
- Usually corticosteroid
Name some staphylococcal antibiotics?
Use in order -
1. Clindamycin, lincomycin, erythromycin
Lincosamides/macrolides – action??
2. Amoxycillin-clavulanate
3. TMPS – cheap but resistance is an issue
5. Cefalexin (20-25mg/kg BID*)
5. Quinolones (C&S only if no alternative)
Canine surface pyoderma Management options?
Topical antibacterial/corticosteroid
- Easy, surface disease, controllable
- Fuciderm (fusidic acid/betamethasone) They have renamed it Isaderm now!!!!
Systemic
- Antimicrobial – injection and tablets?
- Glucocorticoid – 1 S-A injection?
What are these?
Epidermal collarettes (spreading lesion where pustule was, owners often think it’s ringworm)
What is this?
Furuncles within skin discharging to surface
What is this?
Anal furunculosis
- Sinuses that track through the skin round anus
- Occasionally affect inside back legs
- Open areas of ulceration.
- Technically NOT fistulas
- Near the anal sacs but do not connect with them, or rectum or colon
- Cause unknown
- not bacterial (may be 2ry infection)
- tail carriage?
- Most cases seen in GSD
- Lick and bite at the affected region.
- Pain, difficulty straining on defaecation.
- Tail-shy
Diagnosis
physical examination & r/o other causes
Treatment – often recurs
- Cyclosporin - immune mediated condition? Seems to respond well to cyclosporin but it is very expensive
- Radical surgery all diseased tissue removed
- Cryosurgery - apply freezing liquid nitrogen,
What is this?
Juvenile cellulitis: (puppy strangles)
- NOT bacterial!
- Immunological?
- Oedema, pustules, papules, crusts
- Perioral, periocular, chin, muzzle, ears
- Occasionally elsewhere
- Sub-mandibular lymphadenopathy
- Lethargy fever and anorexia in some
- Joint pain in some
- Aspirates - suppurative lymphadenitis with many neutrophils without bacteria.
- Corticosteroids – immunosuppression
- Usually cover with antimicrobials
Discuss Dermatophilus congolensis?
- Actinomycete
- Gram +ve filamentous bacterium.
- Initial infection requires at least superficial skin damage.
- Motile zoospore stage is activated to form a mycelium.
- Confined to the epidermis.
- The zoospore can remain dormant in skin debris and scabs for many months in dry conditions
- Dermatophilosis is contagious only when there is a reduction in systemic or local skin resistance allowing for establishment of infection and subsequent disease.
Discuss greasy pig disease?
Exudative dermatitis
Staphylococcus hyicus
- Dark, localised areas of grease and scale
- Excess sebum – smell!
- Limited in piglets from sow litters?
- May go generalised
- Stress – piglets/weaners
- Gilt litters?
- If severe - skin turns black due to necrosis and the pigs die.
- Can get systemic illness due to toxin release – liver/kidney damage
Often SECONDARY, primary causes:
- Damage – teeth/floors
- Abrasions from poor concrete surfaces or metal floors, troughs, side panels.
- Faulty procedures for iron injections, removing tails and teeth.
- Fighting and skin trauma at weaning.
- Mange giving rise to skin damage.
- Damage to the face by metal feeding troughs can precipitate disease.
- Abnormal behaviour - tail biting, ear biting, navel sucking, flank biting.
Describe Erysipelas in pigs?
- Erysipelothrix rhusiopathiae
- Sudden death
- Very high temperature
- Sick pigs
- Skin lesions
- Lameness
- Reproductive failure
- Penicillin
- Vaccine available
