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107 Cards in this Set
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Normal bacterial flora in dogs (residents): |
1) Coagulase-negative Staphylococcus sp. 2) Streptococcus sp. 3) Micrococcus sp. 4) Acinetobacter sp. 5) alpha-hemolytic Streptococcus sp. |
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Transient bacterial flora in dogs |
1) Bacillus 2) Corynebacterium 3) Escherichia coli 4) Proteus mirabilis 5) Pseudomonas sp |
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Normal bacterial flora residents of cats |
1) Acinetobacter sp 2) Micrococcus sp. 3) Coagulase-negative Staphylococcus sp. |
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Transient bacterial flora of cats |
1) Alcaligenes sp. 2) Bacillus sp 3) Escherichia coli 4) Proteus mirabilis 5) Pseudomonas sp. 6) Coagulase-positive and coagulase negative Staphylococcus sp. 7) alpha-hemolytic Streptococcus sp. |
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What is pyoderma? |
A bacterial skin infection consisting of pus filled blisters that break and crust over Usually superificial and secondary to allergies (flea, food, atopy), endocrine diseases, seborrheic disease, ectoparasites, skin fold anatomy or poor grooming |
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What usually triggers pyoderma? |
Overgrowth of resident Staphylococcus intermedius |
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What is impetigo? |
Superficial pyoderma in puppies |
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Is pyoderma a big deal? |
Usually not serious, can be treated topically |
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What is a deep pyoderma? |
Infection involving the dermis, deep dermis, or cause furunculosis May spread or persist |
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What is otitis externa? |
Acute or chronic inflammation of the epithelium of the external ear canal Most common disease of the ear canal in dogs and cats - occasionally seen in rabbits, uncommon in large animals |
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Parasitic agents of otitis externa |
Ear mites Fleas Mange mites Ticks |
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Bacterial agents of otitis externa |
S. interedius Beta-hemolytic Streptococci Proteus Pseudomonas |
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What other agents can cause otitis externa? |
Fungal Foreign bodies Tumours Allergies |
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Common lab procedures for diagnosing skin diseases |
1. Skin scrapings 2. Combing hair coat 3. Cytology 4. Hair examination 5. Fungal cultures 6. Bacterial cultures 7. Biopsy 8. Intradermal allergy testing 9. CBC/Chem/UA |
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What is the difference between coagulase positive and coagulase negative staph? |
Coagulase positive tend to be more virulent Coagulase negative tend to be opportunistic - usually only pathogenic in mastitis, and even then only cause low grade smouldering subclinical mastitis **EXCEPT S. suis** |
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What are the 3 coagulase positive Staphylococci? |
S. aureus S. intermedius S. pseudointermedius |
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What are the 6 coagulase negative Staphylococci? |
S. epidermis S. simulans S. schleiferi S. sciuri S. felis S. suis - greasy pig disease in piglets! |
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Staphylococcus aureus virulence factors (11) |
1. Capsule - inhibits chemotaxis and phagocytosis, promotes adherence 2. Cell wall peptidoglycan - leukocyte attractant, inhibits complement 3. teichoic acids - binds fibronectin 4. exo-toxins - hemolysins, leukotoxins 5. Protein A - binds immunoglobulin 6. Exfoliative toxins - superantigens 7. Endo-toxin - toxic shock syndrome toxin - superantigen 8. Coagulase - converts fibrinogen to fibrin - clot formation 9. Hyaluronidase - hydrolyzes connective tissue 10. Lipase - hydrolyzes lipids 11. Nuclease - hydrolyzes DNA |
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Which antibiotics are MRSA strains currently resistant to? |
Penicillin Oxacillin Amoxicillin Tetracycline Erythromycin Clindamycin |
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How are new strains of MRSA quickly developed? |
Antibiotic resistance genes and toxin genes are transferred together to other bacteria |
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How is MRSA transmitted? |
Direct contact with carrier, fomites |
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What does MRSA do to animals? |
Animals can be transiently colonized - reverse zoonosis from people Then can transmit MRSA back to people MRSA can cause severe disease in animals |
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Which Staph causes greasy pig disease? |
Staphylococcus hyicus Gram-positive coccus Coagulase negative |
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What is greasy pig disease? |
Exudative epidermitis in suckling and weaned piglets worldwide |
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What is the pathogenesis of S. hyicus? |
1) Predisposition to infection: - sarcoptic mange, high humidity, skin wounds from fighting, rough bedding 2) Virulent strains produce an exfoliative toxin (30-kDA protein) which disrupts cell attachment at the level of the stratum granulosum 3) Excess sebaceous secretion, exfoliation, cellulitis, crusts, vesicles, pustules 4) Death results from dehydration and loss of serum protein from progressive exfoliation |
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What causes ear necrosis in greasy pig disease? |
S. hyicus/S. aureus coinfection |
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Prevention of greasy pig disease |
**Usually an immunity problem!** 1. Teeth clipping to prevent skin wounds 2. Sanitation when ear clipping 3. Sanitation and disinfection of feeders and pen surfaces 4. Prompt treatment of early lesions on sow and piglets 5. Autogenous bacterin - toxoid vaccines prefarrowing for maternal antibody protection of piglets |
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Diagnosis of greasy pig disease |
Based on clinical signs and the age of the affected pigs (7 days to 5 weeks) |
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Treatment of greasy pig disease |
Treat early! Typically penicillin resistant Use Trimethoprim sulfa's and cephalosporins used Topically: surgical scrub, hibitane or Virkon wash, topical antibiotic medication Mineral oil, preferably veggie oil applied to skin Zinc oxide based ointments Maintain hydration! |
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What causes Diamond skin disease in pigs? |
Erysipelothrix rhusiopathiae Gram-positive rod, can be pleomorphic, nonsporulating, alpha-hemolytic World-wide distribution |
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Which animals does E. rhusiopathiae cause disease in? |
Pigs, turkeys, poultry, sheep, cattle, fish |
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How is E. rhusiopathiae transmitted? |
Direct contact with infected animals, fomites |
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What age of pigs does diamond skin disease occur in? |
All ages |
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What clinical signs are seen in diamond skin disease? |
Urticaria Red rhomboid patches on skin Septicemia Polyarthritis Polysynovitis Endocarditis |
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What are the two serotypes in Erysipelas in pigs and how do they differ in disease? |
Serotype 1 - acute disease and death to chronic disease Serotype 2 - Diamond skin lesions, polyarthritis and villonodular synovitis (classic lesion of erysipelas) |
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What does Erysipelas commonly do in unvaccinated sows? |
Cause abortion |
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What do the skin lesions of diamond skin disease occur from? |
Results from antigen/antibody complexes causing vasculitis and thrombus formation - results in infarction of tissue |
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Treatment of Erysipelas in pigs |
Penicillins, cephalosporins |
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Prevention of Erysipelas |
Vaccination |
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What is Erysipeloid and how is it contracted? |
Zoonotic infection with Erisipelothrix, usually from pigs which are the domestic reservoir |
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Can Erisipelothrix survive in soil? |
Briefly |
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What does the human zoonotic Erysipieloid look like? |
Localized cellulitis infection Systemic spread is RARE, unless immunocompromised - then septicemia, polyarthritis, polysynovitis |
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What is Moraxella bovis? |
Proteobacteria Gram negative, short plump rods or short chains, non-motile Fastidious, aerobic |
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Where do most Moraxella species colonize (in the body)? |
Mucous membranes Conjunctiva of commensal hosts Oral cavity, nasal cavity, upper respiratory tract and eyes |
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What causes Bovine Keratoconjunctivitis (IBK, pink eye) |
M. bovis |
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What signs do you see with Bovine Keratoconjuntivitis? |
Serous to purulent conjunctivitis and keratitis, rarely meningitis
Can get melting ulcers in the eye, when Pseudomonas colonizes the wound made by M. bovis |
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What is a mechanical vector for M. bovis? |
The face fly |
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Why is Bovine Keratoconjunctivitis a problem for cow herds? |
Second most common disease in cattle, and has an important economic impact: - decreased growth - decreased milk production - disfigurement - decreased marketability |
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Transmission of M. bovis |
Animal to animal Direct contact with ocular or nasal exudates or fomites Mother licking newborn calves Intra and interherd transmission by flies |
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When do we see seasonal outbreaks in grazing cattle of M. bovis? |
Summer and early autumn |
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What age of cattle are more resistant to M. bovis? |
>2 years of age |
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Virulence factors of M. bovis(3) |
1) Q-pilus - mediates attachment to corneal surface 2) I-pilus - local persistence and maintenance of infection 3) Cytotoxins - Cytolysin/hemolysin - produced after colonization a) pore forming b) promotes formation of ulcers through lysis of corneal epithelium c) lysis of host neutrophils -> leakage of degradative enzymes -> corneal liquefaction and ulceration |
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Diagnosis of M. bovis |
Clinical signs Isolation of organism from conjunctival swabs or lacrimal secretions |
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Why do you need to deliver samples of what you think is M. bovis to the lab very quickly? |
M. is extremely fragile and has limited viability outside the host |
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Treatment of M. bovis in cattle |
Antimicrobials and isolation of affected animals Two injections of long-acting oxytetracycline formulations at 72 hour intervals |
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Prevention of M. bovis |
Insidious disease, therefore prevention better than treatment! Eliminate the contributing factors: - controlling face flies (insecticides) - proper pasture management - mowing tall grasses and weeds (reduce flies) - proper nutrition - adequate shade - UV light |
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What is Chlamydiophila felis and what does it cause? |
Infectious conjunctivitis in cats! Gram negative Non-motile, spherical Cell- wall differs from gram-negative bacteria: no peptidoglycan Obligate intracellular microorganisms |
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True or false, Chlamydiophila felis is unstable outside the body |
True! Survival in lacrimal fluid <3 days |
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What is Chalmydiophila felis very sensitive to? |
Antiseptics |
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Unique life cycle of Chlamydiophila felis? |
1. Intracellular form: reticular body 2. Extracellular form: elementary body |
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Transmission of Chlamydiophila felis |
Direct contact Infectious conjunctival or nasal secretions Paws Infected objects (very short amount of time) |
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Clinical signs of Infectious feline conjunctivitis |
Predominantly: inflammation of conjunctiva and nictitating membrane **Squinty eyed cats!** Initially: serous ocular secretions, blepharospasm, chemosis and hyperemia Secondary: mucopurulent discharge Upper resp signs: fever, ocular discharge, sneezing |
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Can c. felis spread into the body? |
Yes. Spreads internally to colonize many tissues: - tonsil - lung - liver - spleen - kidney |
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True or false: Infections with C. felis resolve quickly
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False! Infections are persistent and often become chronic and insidious Cats may be asymptomatic carriers - organisms in the conjunctiva, and shed for up to 18 months |
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Which organisms can co-infect with C. felis? |
Feline coronavirus, FHV-1, Bordetella, Mycoplasma Increases the clinical severity of infection and duration of shedding |
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Which secondary infections can be seen with C. felis? |
Streptococcus sp Staphylococcus sp. Mycoplasma felis |
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Diagnosis of Infectious feline conjunctivitis |
Persistent conjunctivitis Rising antibodies (paired sera: 3-4 weeks) Isolation difficult, can only culture in cell cultures - obligate intracellular pathogen Conjunctival smears - stamp stain, show intracellular inclusion bodies in beginning of infection (day 4-7) Immunofluorescence on smears PCR conjunctival swabs, brushings |
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Treatment of infectious feline conjunctivitis |
Topical tetracycline opthalmic ointment (3 weeks) |
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Prevention of IFC |
FVRCP vaccination reduces co-infections |
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What is mycobacterial dermatitis? |
Mycobacterial skin disease in cats - associated with atypical mycobacteria - uncommon in cats, rare in dogs! Mycobacteria should be considered in cases of chronic nodular dermatitis, draining tracts and panniculitis |
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Diagnosis of mycobacterial dermatitis |
Histopath findings Growth of causative organisms PCR |
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Treatment of mycobacterial dermatitis |
Based on antibiotic sensitivity test results Treatment is prolonged and unsuccessful in many cases |
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What is feline leprosy? |
Cats develop granulomas of the subcutis and and skin in association with intracellular acid-fast bacilli that do not grow on routine lab media The mycobacerial species can be identified by PCR |
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Which Mycobacterium cause feline leprosy? |
Mycobacterium lepraemurium in young cats Novel mycobacterium in older cats |
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Which mycobacterium cause opportunistic infections? (4) |
Mycobacterium chelonei M. fortuitum M. smegmatis M. phlei |
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What do Eumycetomas and Actinomycetomas cause? |
Chronically progressive granulomatous, locally destructive subcutaneous infections that share clinical appearance Lesions may affect underlying bone May form fistulas and draining tracts Prognosis guarded due to extensive tissue involvement |
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What is most commonly isolated from Eumycetomas? |
Fungi |
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What is most commonly isolated from Actinomycetomas? |
Bacteria - Actinobacillus - Nocardia - Actinomyces |
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Treatment of granulomas due to Eumycetomas and Actinomycetomas? |
Radical surgical excision, long term anti-fungal or antibiotic therapy |
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What is Nocardia asteroides? |
Actinomycete - gram positive, aerobic, nonmotile, pleiomorphic - has muramic acid in cell wall, no membrane bound mitochondria and nucleus Opportunistic pathogen of wounds, that lives in soil, compost, fresh/salt water, feces - usually infects animals that are immunosuppressed |
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What is Nocardiosis? |
Infection with Nocardia sp. Suppurative to granulomatous infections 1. Pulmonary 2. Systemic or disseminated 3. Solitary non-pulmonary cutaenous or subcutaneous abscess, lymph node abscess |
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What is Dermatophilus congolensis? |
Actinomcyte - gram positive, aerobic, catalase positive - resembles "rail road tracks" Obligate symbiotic parasite, environmentally resistance and affects a wide range of hosts: - cattle, goats, reptiles, wildlife, cats, dogs, pigs, seals |
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How is Dermatophilus congolensis spread? |
Direct contact Fomites Biting insects (ticks) |
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Predisposing factors to infection by Dermatophilus congolensis |
Chronic exposure of skin to trauma or moisture Immunosuppressive therapy Concurrent debilitating disease |
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True or false, dermatophilus congolensis is zoonotic? |
True |
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Pathogenesis of D. congolensis |
Hemophilic Excrete phospholipases and proteolytic enzymes - may play a role in penetration of epithelial barrier and invade hair follicles High [CO2] - deeply seated zoospore population in tissue produces high [CO2] -> accelerates their escape to surface of epidermis -> accelerated infection/spread |
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What is Dermatophilus disease called in cattle and horse? |
Mycotic dermatitis - causes "rain scald" or "rain rot" - also "lumpy skin disease" in cattle |
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Dermatophilosis in pets present with which clinical signs? |
Generalized exudative dermatitis |
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Treatment of rain rot in horses |
Antimicrobial and antibacterial shampoos and rinses Topical Betadine, Phenol or Nolvasan application once a day or week |
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Diagnosis of Dermatophilosis |
Remove dry scabs or take biopsy samples Wet mounts stained with new methylene blue Dry mounts with Giemsa |
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Is Dermatophilosis important in humans? |
Human infection is usually self-limiting and regresses gradually without treatment - but can recur if skin remains moist |
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Geographic distribution of dermatophilus and tick vector |
Worldwide - higher in rainy season |
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Aerobic species that infect surgical wounds |
Coliforms, enterocci, staphylococci, Pseudomonas |
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Anaerobic species that infect surgical wounds |
Bacteroides |
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How are surgical wounds often infected? |
1. Patients endogenous microflora - disinfection does not completely get rid of skin flora - bacteria can reside in deeper parts of the skin, such as follicles, sebaceous glands 2. Inadequate sterilization of surgical equipment 3. Inadequate or improper operating room air flow 4. Contaminated staff - MRSA, VRE 5. Poor surgical technique - vascular compromise to tissue - excessive electrocautery - bleeding into tissue spaces (blood clots allow adherence and replication) |
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Signs seen with surgical wound infection caused by Serratia marcescens |
It's an environmental bacteria - firm, painful edema where wound is, tachycardia, dry mucous membranes, increased temp etc Forms an excellent biofilm |
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Prevention targets to minimize occupational infections |
Exposed people Exposed animals Infectious agents Host animals Environmental sources |
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What is erythema nodosum? |
Most common form of panniculitis (inflammation of subcu fat) Frequently associated with fever, malaise, joint pain and inflammation presents as smooth, shiny, tender red nodules on shins Many infectious agents associated with it!! |
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Which 3 organisms cause systemic manifestations from bite wounds? |
Pasteurella multocida Capnocytophaga canimorsus Eugonic fermenter 4b (unclassified) |
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Which pathogen commonly causes cat bite abscesses in cats? |
Pasteurella multocida Also causes human cellulitis from cat bites - pain, redness, swelling |
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What is pasteurella multocida sensitive to? |
Penicillins, tetracyclines, chloramphenicol |
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Which species typically infect after a dog bite? |
Neisseria - Animaloris - Canis - Weaveri - Zoodegmatis Acinetobacter sp. - use penicillins, ampicillins, cephalosporins |
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Which species is associated with infection in aquarium fish? |
Mycobacterium - signs of fish tuberculosis (curved spine, wasting, skeletal deformity, nodules, ulcers) |
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Why are fish tank granuloma infections hard to treat? |
The bacteria are neither truly gram + or gram - so they are naturally resistant to antibiotics that target the cell wall |
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Which species associated with infection in pet snakes, amphibians and fish? |
Aeromonas - opportunistic pathogen of cold-blooded animals Related to poor husbandry and cold temp, which predispose pets to infection |
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How is Aeromonas transmitted in humans? |
Fecal oral route, skin or eye contact with contaminated water, food soil feces, contaminated fish or reptiles |
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Which 4 diseases forms are present in humans infected by Aeromonas? |
Granuloma Cellulitis Myonecrosis Ecthyma gangrenosum |