Lab 8.2: Pyoderma & Otitis
1.) Canine Pyoderma is also called Canine _______ _______ ________.
2.) What is the most common isolate from pyoderma in dogs?
3.) Otitis and pyoderma are often caused by an _______ of normal microbiota.
1.) Superficial Bacterial Folliculitis
2.) Staphylococcus pseudointermedius
3.) overgrowth
1.) The infective spore of a dermatophyte is _______, not macroconidia. If ______ are seen on a sample taken directly from an animal, it is likely a contaminant and not infection.
2.) In cats and dogs, _______ ____ is the most common cause of Dermatophytosis. This fungus is extremely contagious and the arthrospores adhere to/infect hair shafts, resulting in an identifiable structure called an _____. These arthrospores will glow under a specialized UV light called a _____ ____.
3.) True or False. Endothrix will fluoresce on a Wood's Lamp.
1.) arthroconidia (infective spore), macroconidia
2.) Microsporum canis, ectothrix, Wood's lamp
3.) False! Endothrix don't glow; Ectothrix glow.
1.) Actinomyces or Nocardia? Found in the soil
2.) Actinomyces or Nocardia? Normally present on mucous membranes of animals
3.) Actinomyces or Nocardia? Migrating grass awns/foxtails
1.) Nocardia
2.) Actinomyces
3.) Actinomyces
1.) The majority of mastitis cases are caused by the same three basic groups of bacteria. What are they?
2.) What are the 4 stages of a lactation cycle?
3.) ___ are females who have had at least one calf. A ____ is a female who has not yet calved. As you know, producing milk starts with cows. Once a cow has given birth, that cow can be milked for about ___ days before it needs to dry off to prepare to have another calf.
1.) 1. Staphylococcus species 2. Streptococcus species 3. Enterobacteriaceae (E. coli, Klebsiella, Proteus)
2.) 1. Early Lactation 2. Mid Lactation 3. Late Lactation 4. Dry Period
3.) Cows, heifer, 300
1.) Name 3 important bacterial pathogens that cause contagious mastitis in dairy cows
2.) Name 3 important bacterial pathogens which cause environmental mastitis in dairy cows
1.) Streptococcus agalactiae, Staphylococcus aeurus, Mycoplasma bovis
2.) Streptococcus dysgalactiae, Coliforms (like E. coli, Klebsiella), Staphylococcus species
1.) True or False. Treating pyoderma as well as otitis involves addressing the pathogen in addition to predisposing conditions, pruritis, pain, and inflammation.
2.) Pyoderma literally means "__ in skin". The most frequently involved etiologic agents are pyogenic bacteria, such as ________.
3.) Name 2 gram positive bacteria, 1 yeast, and 3 gram negative bacteria that are more frequently implicated in otitis cases in dogs.
1.) True
2.) pus, staphylococcus
3.) Gram positive - Staph, Strep. Yeast - Malassezia pachydermatitis. Gram negative - Pseudomonas aeruginosa, E. coli, Proteus.
1.) Explain why this is True or False: If you see fluorescence of a lesion under a Wood's Lamp, then that is a definitive diagnosis for Ringworm (aka Dermatophytosis).
2.) When scraping crusty material or plucking hair from a lesion you suspect is ringworm, should you sample from the periphery or center of the lesion?
3.) If you place the paintbrush lesions on a slide, then what form/appearance of Dermatophilus will you see?
1.) False. Debris, scales, blood, and topical medications commonly elicit a false fluorescence. Ringworm with endothrix don't fluorescence. In addition, ~50% of Microsporum canis lesions will fluoresce (which ~50% will not!).
2.) Periphery
3.) Tram-track appearance
1.) Actinomyces or Nocardia? Opportunistic infection after trauma/wounds to mucous membranes
2.) Actinomyces or Nocardia? Tends to be more refractory to treatment and chronic infections are associated with poorer prognosis
3.) Canine Actinomycosis occurs when Actinomyces viscosus gains access to wounds through _____.
4.) Actinomyces or Nocardia? Form 'club colonies' in tissues
5.) Actinomyces or Nocardia? Rarely associated with sulfur granules
1.) Actinomyces
2.) Nocardia
3.) licking
4.) Actinomyces
5.) Nocardia
1.) Infection of the mammary gland almost always occurs via the ___ ____.
2.) Dairy cattle ideally have __ calf every year
3.) This ___ ____ is the primary barrier against intramammary infections, and it is kept closed with a _______. This sphincter must relax for milking and then stays open about an hour after milking, making this a critical time for _____ prevention. The canal is also lined with ____ which helps seal this opening and inhibits bacterial growth.
1.) teat canal
2.) one
3.) teat canal, sphincter, mastitis, keratin
What is the most likely source for the mastitis pathogen in the following – environmental or contagious?
1.) Scenario 1: A gram-negative rod identified from a subclinical mastitis case.
2.) Scenario 2: Gram-positive cocci identified in a systemically sick cow, recently calved, with gangrenous mastitis and large abscesses of the udder. Two other cows are affected and refractory to therapy.
1.) Environmental (Coliforms are gram negative rods)
2.) Contagious (Staph aeureus)
1.) What's the definition of otitis externa?
2.) True or False. Predisposing factors such as genetics/hypersensitivities/environment are often involved in otitis pathogenesis and should be addressed during treatment.
3.) How many Malassezia yeast, cocci bacteria, and rod bactera might you see in a DISEASED ear on 40X objective on microscope?
1.) Inflammation of external ear canal
2.) True
3.) >/= 5 malassezia, >/= 25 cocci, >/= 1 rod
Lactophenol Cotton Blue (LPCB) stain is a premier mounting medium and staining agent used to identify dermatophytes (fungi causing skin, hair, and nail infections) by staining chitin in fungal cell walls blue. It ___ fungi via phenol, preserves structure via lactic acid, and stains hyphae and conidia. LPCB is highly effective for microscopic identification of dermatophytes
kills
1.) Actinomyces and Nocardia are both gram-_____, filamentous, branching ___ that cause _________ reactions in tissue.
2.) Actinomyces or Nocardia? Strict aerobes
3.) Actinomyces or Nocardia? High lipid content in cell walls (which makes it more refractory to treatments)
4.) Actinomyces or Nocardia? Do not form 'club colonies' in tissues
1.) positive, rods, pyogranulomatous
2.) Nocardia
3.) Nocardia
4.) Nocardia
1.) Most mastitis is ______ and detected through increased _____ _____ _____ in the milk since there is rarely a change in the appearance of the milk, but production losses may be noted.
2.) What test do we commonly use to test for Somatic Cell Counts (SCC) in milk?
1.) subclinical, somatic cell counts
2.) California Mastitis Test (CMT)
1.) The CMT is used to detect subclinical mastitis by estimating somatic cell counts (SCC) in milk – the SCC reagent reacts with nucleated cells, usually neutrophils, in mastitic milk. The CMT also detects pH changes – mastitic milk is more _____.
2.) When using a Tri-Plate to diagnose a mastitis pathogen:
- Gram _____ bacteria grow well on MacConkey agar but will struggle to grow on Factor or Focus media.
- Gram _____ bacteria grow well on Factor media, but will struggle to grow on MacConkey agar.
- Of the gram-positives, only the _______ will grow well on BOTH Factor and Focus media.
1.) alkaline
2.) negative, positive, streptococci
1.) True or False. Rods may or may not be significant if you see them on an ear cytology.
2.) True or False. Low numbers of commensals, such as Staph (cocci) and Malassezia (yeast), may not be significant and must be interpreted in context for each case.
1.) False! Any rod is considered significant! Gram negative rods aren't common commensals of the skin, but they're commonly implicated in otitis cases, so considered significant.
2.) True
1.) Dermatophilus congolensis infects the outermost layer of the _____ to cause a disease also known as “rain rot” or “rain scald”. While we now know this is a bacterial infection, it is often mistaken for ____ disease and has fungal-like growth characteristics.
2.) This bacterium will lie dormant within the skin until there is a barrier breakdown. Sometimes that is due to prolonged wetness, high humidity, trauma from biting flies or heat. Dermatophilus produces infective ______ which germinate in compromised skin
3.) Is Dermatophilus congolensis gram positive or gram negative?
1.) epidermis, fungal
2.) zoospores
3.) Gram positive
1.) Actinomyces or Nocardia? The actinomycetes are generally commensals of mucous membranes that cause chronic, pyogranulomatous infections when they gain access to tissues outside the mucous membranes.
2.) What's the etiologic agent of Lumpy Jaw in cattle?
3.) Actinomyces or Nocardia? Sulfur granules are common
1.) Actinomyces
2.) Actinomyces bovis
3.) Actinomyces
Complete the sentences with the appropriate term. You can select from subclinical, mild clinical/ localized, severe acute, and chronic clinical presentations.
1.) A California Mastitis Test is used to detect ____________ mastitis.
2.) A febrile, lethargic goat with a painful and inflamed teat has ________________ mastitis.
3.) Reddish milk from an inflamed quarter with no signs of systemic disease indicates __________ mastitis.
4.) ___________ mastitis can appear as an atrophied quarter with firm areas on palpation.
5.) Most cases of mastitis are _____________.
1.) subclinical
2.) Severe acute
3.) Mild clinical/localized
4.) Chronic clinical
5.) subclinical
1.) A _____ CAMP test is indicated by an arrowhead of complete hemolysis, which is indicative of ________ ________.
2.) A negative CAMP test, which is just a straight line (no arrow of hemolysis), is indicative of Streptococcus ________.
3.) When using a Tri-Plate, Focus media is selective for __________ species. Factor media is selective for gram ______ bacteria. MacConkey media is selective for gram _______ bacteria. On MacConkey media, lactose fermenters (such as Coliforms) will have ___ colonies.
1.) positive, Streptococcus agalactiae
2.) dysgalactiae
3.) Streptococcus, positive, negative, pink
True or False. Generally, dermatophilosis is self-limiting and will eventually heal on its own. However, the lesions can progress and cause pain and discomfort for the animal, in particular if the lesions are under a saddle. Most of these infections respond well to bathing the horse with an antimicrobial shampoo followed by a good currying to remove the scabs and paintbrush lesions. Deeper, severe infections may require systemic antimicrobials.
True
1.) Actinomycetes form ‘___ colonies’ within deeper tissues through a host response to the chronic infection. The filamentous organism will grow within the tissue and be surrounded by areas of mineralized calcium phosphate. These lesions become _________ and ____ and will develop sinus and draining tracts with purulent exudate containing ‘____ _____’. These granules will have club colonies within them if crushed and examined under a microscope. Collectively, the fibrotic, granulomatous nodules formed in the deeper tissue are called ________.
2.) True or False. Nocardiosis affects several species of mammal and fish, but dogs are the most common. The disease is more _____ than actinomycosis with regional or widespread abscess/granuloma formation and lymph node involvement. The invasive nature of this pathogen as well as treatment challenges due to its unique morphology make nocardiosis difficult to treat. Nocardiosis is also associated with cases of chronic mastitis that are refractory to therapy and often result in culling.
1.) club, granulomatous, fibrotic, sulfur granules, mycetomas
2.) True
1.) Lactating or Dry cow intramammary infusions?
- TODAY®
2.) Lactating or Dry cow intramammary infusions?
- TOMORROW®
3.) True or False. You can use dry cow therapy on a lactating cow.
1.) Lactating cow intramammary infusions
2.) Dry cow intramammary infusions
3.) False! Don’t use dry cow therapy on a lactating cow!
On the Tri-Plate, Lactose fermenters will have pink colonies on _______ agar. Most _____ are considered lactose-fermenters. Staphylococcus ______ will grow well on Factor media (not Focus or MacConkey) and also has a clear zone of hemolysis surrounding that growth.
MacConkey, coliforms, aureus