Module 1 MiniModule 4: Microbiology of the Skin and Ears Flashcards
What is normal microbiota?
Microorganisms that live (reside, multiply) in different body sites of an individual
Which are the most common bacteria isolated from the skin of a dog?
- Staphylococcus spp (gram +)
- S. pseudintermedius*
- S. schleiferi
(T/F) Pyogranulomatous infections are difficult to diagnose and treat
True
List examples of normal microbiota found in the skin of dogs:
- Staphylococcus spp
- Malassezia spp
Definition:
Microorganisms that colonize the host for short periods of time
Transient Microbiota
- usually don’t reproduce in the host
- usually eliminated by host
- usually do not persist for a long defenses
List examples of environmental microorganisms:
- Pseudomonas spp
- Aspergillus spp (tends to be a transient microorganism)
Definition:
Organisms that can become pathogenic following a perturbation to their host (e.g., disease, wound, medication, prior infection, immunodeficiency, and aging)
Opportunistic Microorganisms
(T/F) Transient and/or normal microbiota can NOT become “opportunistic” pathogens
False, they can become opportunistic pathogens
Definition:
It is typically used to differentiate S. aureus from other Gram + cocci
Coagulase Test
The following are examples of ….
- S. aureus
- S. intermedius Group (SIG)
- S. schleiferi
Pathogenic Staphylococcus
The following are examples of …
- S. epidermidis
- S. xylosis
- S. warneri
Non-pathogenic Staphylococcus
In what species is S. aureus considered a normal microbiota?
Humans
- A high % of humans are colonized
In animals, S. aureus is most likely considered a __________ microbiota
Transient
- dogs will spontaneously decolonize S. aureus (2-3 weeks)
(T/F) Staphylococcus pseudintermedius can become pathogenic
True, this is due to virulence factors
The following clinical signs are associated with …
- pyogenic bacteria
- wound infections
- respiratory disease: pneumonia
- joint infections
Streptococcus spp (Gram +)
- Beta-hemolytic (S. canis, S. equi subsp zooepidemicus)
- Gram-negative bacilli, found in the environment
- Superficial - deep infections - wound infections in humans and many animal species
- When clinically important, it is difficult to treat -> Multidrug-resistant (antimicrobial) ** important to know **
- Many virulence factors. Produce pyocyanin pigment -> green color
- Biofilm
This is describing what?
Pseudomonas aeruginosa
Other Gram-negative “rods”:
Normal microbiota (commensal) of the oral and nasal mucosal surfaces
Pasteurella spp
Other Gram-negative “rods”:
Several members of this group are normal microbiota (commensal) in the intestine of animals and humans
Enterobacterales
- E. coli
- Proteus spp
- Klebsiella spp
- Enterobacter spp
Definition:
An infection confined to the superficial portion of the hair follicle (superficial skin infection)
Superficial pyoderma (bacterial folliculitis)
- Etiology: S. pseudintermedius
List the Clinical Signs for Superficial Pyoderma in dogs:
- Erythematous papules
- Pustules
- Variable:
- Crusts
- Papules
- Alopecia
What would be the best diagnosis for Superficial pyoderma in dogs?
- Cytology *
- Culture & Susceptibility
Definition:
Refers to diffuse infection and inflammation along tissue planes (going a bit deeper into the skin)
Cellulitis
- Etiology: Pasteurella multocida, S. pseudintermedius
What is the spp most commonly associated with cat scratch cellulitis?
Pasteurella multocida
List the signs of Deep pyoderma:
- Hemorrhagic bulla, draining sinuses, ulcers, edema, and severe inflammation
- Hemorrhagic and/or purulent discharge
- Pain
- Etiology: S. pseudintermedius, Pseudomonas aeruginosa
Definition:
- Rapid & progressive necrotizing infection of the skin, soft tissue, and deep fascia
- Uncommon
- Reported in humans, dogs, and cats
Necrotizing Fasciitis
The following clinical signs described …
- Lethargy, fever
- Soft tissue inflammation
- Extremely painful
- Epidermis may look normal
- May extend to deeper tissues and bone -> shock, CID, death
Necrotizing Fasciitis
What is the etiology of Necrotizing fasciitis?
- Streptococcus canis (group G)
- Staphylococcus pseudintermedius
List the most common pathogenic microorganisms causing otitis in dogs:
- S. pseudintermedius
- P. aeruginosa (greenish mucopurulent secretion)
- Proteus mirabilis
- Malassezia pachydermatis
Definition:
- A tumor in which polymorphonuclear cells have invaded an inflammation consisting of mononuclear cells
- non-degradable products can be foreign bodies and/or microorganisms, specifically bacteria and fungi
Pyogranuloma
List the etiology of Pyogranuloma:
- Actinomyces spp
- Nocardia spp
- Mycobacterium spp
- Corynebacterium spp
(all of these bacteria are Gram-positive “Rods”)
Definition:
Coryneform bacteria are normal microbiota of the skin and other mucosal membranes
Corynebacterium spp
Caseous lymphangitis and Ulcerative lymphangitis (Pigeon fever) are under …
Corynebacterium pseudotuberculosis
- Non-healing, granulomatous, or cutaneous abscesses
- With the most common being:
- C. auriscanis
- C. ulcerans
What is this describing?
Corynebacterium spp (Gram +)
- Normal oral microbiota
- Strict or facultative anaerobes (anaerobic culture)
- Example: Lumpy jaw (bovine)
What is this describing?
Actinomyces spp (Gram +)
- Actinomyces bovis
- A. canis
A. viscosus
- The bacteria are ubiquitous (found everywhere) -> soil, water, environment
- Obligate aerobes
- Example: Mastitis (in the US)
What is this describing?
Nocardia spp (Gram +)
- Bovine nocardiosis
- N. asteroids
Definition:
The bacteria usually attack the lungs, but the bacteria can attack any part of the body such as the kidney, spine, and brain
Mycobacterium tuberculosis
Uncultivable Mycobacteria:
Nodules of the skin and/or subcutis (which tend towards ulceration) on the head and/or forelimbs
M. lepraemurium also known as Feline leprosy
Uncultivable Mycobacteria:
Nodular granulomatous to pyogranulomatous lesions in the skin and/or subcutis
Canine leproid granuloma
Fungus, Yeast:
Otitis externa & seborrheic dermatitis
Malassezia pachydermatis
Fungus, Yeast:
Occasionally, subcutaneous granulomas often in the cervical regions
Cryptococcus
** Don’t need to know for Exam 1 **
Definition:
fungi that have a yeast (or yeast-like) phase and a mold (filamentous) phase
Dimorphic fungi
** Don’t need to know for Exam 1 **
Dimorphic fungi:
Subcutaneous nodules, lymphatics
Sporothrix
** Don’t need to know for Exam 1 **
Dimorphic fungi:
Primary lesions in lungs, but metastases to skin and other organs
- Blastomyces
- Coccidioides
** Don’t need to know for Exam 1 **
Dimorphic fungi:
Subcutaneous nodules, lymph nodes
Histoplasma
List the options when requesting a lab test:
- Aerobic culture
- Anaerobic culture: Actinomyces spp
- Mycology culture
- Mycobacterium culture
- Stains (Gram-stain, Acid-fast)
- PCR -> Nocardia, Mycobacterium, fungus
Which lab test is the following:
- Used to differentiate Gram-positive rods
- if positive: Mycobacterium and Nocardia
Acid-fast
What is in the mouth’s normal microbiota in mammals and can cause pyogranulomas?
Actinomyces spp.
Which of the following Gram neg. “rod” is not a normal microbiota in the intestine of animals and humans?
a. E. coli
b. Pasturella spp
c. Prouteus spp
d. Klebsilla spp
e. Enterobacter spp
b, Pasturella spp, because this is a normal microbiota of the ORAL and NASAL mucosal surface
