Final Exam: Skin infections Flashcards
What is one of the first clinical signs you may see that would lead to you consider a fungal infection?
Alopecia
If you see a patient with dermatitis or pyoderma, the first thing that comes to your mind is..?
bacterial infection
may be secondary - but is causing pyoderma
What is panniculitis?
inflammation of SQ fat
What is cellulitis?
Inflammation of the dermis and SQ fat - dissects through tissue planes
What types of bacteria would you suspect with an infection presenting with suppurative inflammation?
Granulomatous?
pyogranulomatous?
Suppurative - pyogenic bacteria like Staph
Granulomatous - more complex bacteria like Mycobacteria
Pyogranulomatous - Nocardia, corynebacterium, atinobacillus, actinomyces
Since many skin infections have a similar outward appearance, what are some things that you must not forget to take into consideration?
Geographic location
Weather
Distribution/location on body
Detailed history from owner (ectoparasites? access to water? ect)
What is the MOST COMMON pyogenic bacteria seen in dogs?
NEVERFORGET
Staphylococcus pseudintermedius
T/F: Methicillin resistant staphylococcus means that bacteria is resistant to methicillin only
FALSE
Resistance to multiple antimicrobials
When performing a bacterial culture and susceptibility, what should be collected?
Fresh purulent discharge or fresh tissue. Using a swab (should never be sent in dry for a culture)
T/F: Dermatohistopathology can be useful in ruling out fungal infections
TRUE
also helps rule out autoimmune, and neoplastic differentials
What is important to keep in mind when treating a skin infection?
**there is almost always an underlying cause! If that is not treated, you will have repeat infections
What staphylococcus isolates should be considered Clindamycin resistant?
Staph isolates which are macrolide (erythromycin) resistant.
Due to inducible clindamycin resistance
What is the etiology for Greasy Pig Disease?
Staphylococcus hyicus
Piglets 1-6 weeks of age
What is the etiology for Bumble Foot in chickens?
Staphylococcus aureus
*can also cause pyogranulomatous infections in lab mice, humans, and horses
Staphylococcal species with super antigens can cause what syndrome?
TOXIC SHOCK SYNDROME
What is the etiology of feline leprosy?
Common etiology of lymph node abscess in cats?
Common etiology of cat bite abscesses?
- Feline leprosy = mycobacterial infections
- LN abscess = Yersina pestis
- Cat bite abscesses = Pasteurella spps
T/F: Clostridium is a gram POSITIVE anaerobe
TRUE
There is one gram negative clostridium = piliforme
What bacteria can cause pyoderma in dogs post operatively, and sometimes have a green/blue appearance and sweet odor?
Pseudomonas aeruginosa
facultative pathogenic - usually secondary infection
T/F: Coagulase negative staphylococci often cause disease in immunocompetent animals
FALSE
**less pathogenic than coagulase positive staph
Rarely will cause dz in animals with a functional immune system
Are topical or systemic antimicrobials preferred to treat superficial skin infections?
Judiciously choose topical vs systemic when possible- to decrease antimicrobial resistance
You are concerned you are a carrier of MSRP, and would like to have a culture confirm that, from where do you collect a sample?
Nasal swab!
Humans are often carries of MRSP - nares are the most common site of colonization
What is the most common mode of transmission of ring worm from pet to human? What animal is usually responsible and what fungus?
Cats are often asymptomatic carriers of Microsporum canis - direct contact with owner
You take a sample from a a cow that has a scabby head and back, under the microscope you see bacteria that have a distinct “train track” appearance. What does your scabby cow have?
Dermatophilis congolensis
What disease does Actinomyces bovis cause?
Lumpy jaw
pyogranulomatous osteomyelitis
What anaerobe causes foot root in cattle, sheep, and goats?
Fuscobacterium necrophorum
Hairy heel warts is caused by what bacteria?
Who is affected?
Treponema spps
Cattle - causes lamenes
Which matching is incorrect? What is the common name for these pathogens?
- Dogs - Microsporum. Canis, M. gypseum
- Cattle - Trichophyton verrucosum
- Cats - Microsporum felis
- Equine - Trichophyton mentagrophyts, T. equinum
3 is incorrect
Cats = Microsporum canis
These all cause ringworm
superficial infection of keratinized skin/hair follicles
What disease is caused by Erysipelothris rhusiopathia? In what animals?
Diamond skin disease in pigs
**systemic dz
Nitrate reducing Corynebacterium pseudotuberculosis causes what disease in which animals?
Causes pigeon fever aka Colorado strangles aka dry land distemper in horses
Ulcerative lymphangitis of the lower extremities
What does swamp fever in horses resemble? What pathogen is the cause?
Resembles proud flesh or excessive granulation tissue
Causes by pithiosis - water fungus like microgranism
A dog comes into your clinic with a granuloma, that you decide to surgically explore/excise. Inside the mass you find a fox tail grass among pyogranulomatous material. You collect a sample for culture, what pathogen do you suspect to find and what test do you run?
Actinomyces hordeovulneris - commonly associated with fox tail grass FB
Need to run an aerobic and anaerobic culture bc atinomyces spps can be either aerobic or anaerobic
What antifungal is useful for treating dermatophyte infections? What is the MOA and the mode of administration?
Griseofulvin
Is active in keratinocytes - inhibits mitotic division of fungus. Admin PO only
If you are treating a bacterial infection with aminoglycosides, but see no improvement after a full course of treatment, what should you suspect?
That the infection you are treating is cause by anaerobic bacteria
aminoglycosides are ineffective against anaerobic bacteria
T/F: Bulckholderia mallei is an obligate pathogen of horses
TRUE
B. mallei = glanders
B. pseudomallei = Melioidosis –> horses can get this from the environment
Cryptococcus affects what animals the most? What is the parthenogenesis?
Cats!
Dz of immunocompromised cats
Causes granulomatous lesions in the upper resp. tract, face, and CNS
Where do you see lesions from Sporothrix schenkii?
SQ lesions restricted to skin nodules and regional lymphatic involvement
seen most frequently in horses and cats
What bacteria causes abscess formation of the retropharyngeal LN in horses? What is the disease is causes?
Streptococcus equi
Causes strangles
*reportable
What pathogen causes caseous lymphadentitis in goats and sheep?
Corynebacterium pseudotuberculosis
