Pseudomonas Flashcards
Pseudomonas: Gram ________? Shape?
Gram Negative, Rods
Pseudomonas: Aerobic/Non-aerobic?
Obligate aerobe
Pseudomonas: Motile/Non-motile?
Motile
Pseudomonas: Distribution? Opportunist?
Ubiquitous - Worldwide - Remarkable capacity to adapt & thrive in diverse ecological niches **Opportunistic Pathogen**
Pseudomonas: What is the strain of veterinary importance?
P. aeruginosa - Secondary agent
Pseudomonas: Does it exhibit antimicrobial sensitivity?
**Significant antimicrobial resistance** R plasmids!
Pseudomonas: Places it can be found in the environment?
Wet, poorly aerated environments -Surgery areas w/support bags -Hoses in anesthetic machine -Mastitis preparations/infusions -Semen extenders -Irrigation Fluids -Hydrotherapy baths -***Endotracheal tubes
Pseudomonas: Virulence Factors
-Adhesins (different types) -Capsule -Cell Wall LPS -Extracellular Slime/Biofilm -Siderophores (types) -Exotoxins -Others: Elastase, Proteases, Phospholipase C (hemolysin)
Pseudomonas: Types of Adhesins
-Fimbrial, Type IV pili, bind glycoproteins on epithelial cells -Non-Fimbrial (OMPs) -Affinity for mucin -Flagella & LPS - Affinity for Cl- channels
Pseudomonas: Types of Siderophores
Pyochelin & Pyoverdin
Pseudomonas: Types of Exotoxins
T3SS - **Exotoxin A** -Exotoxin S, T, U & Y
Pseudomonas: Exotoxin A function
Inhibits protein synthesis
Pseudomonas: Exotoxin S & T function
Affect actin cytoskeleton, interfere with phagocytosis
Pseudomonas: Exotoxin U function
Cytotoxic effect
Pseudomonas: Exotoxin Y function
Increases intracellular cAMP to cytopathic levels
Pseudomonas: Miscellaneous products
Bacteriocins & Pigments -Toxic to bacteria and eukaryotic cells
Pseudomonas: Bacteriocins (Pyocins)
Useful epidemiologically
Pseudomonas: Pigments (Pyocyanins)
Use Diagnostically -Produce O2 radicals toxic to eukaryotes & prokaryotes -Self-protected by catalase & superoxide dismutase
Pseudomonas: Catalase and Superoxide dismutase function
Protect from O2 radicals produced by pigments/pyocyanins to kill host cells
Pseudomonas: Reservoir
Soil, water, feces of normal animals (NOT normal flora)
Pseudomonas: Transmission
Secondary to compromised host (environmental or endogenous)
Pseudomonas: Pathogenesis
Reduced normal flora / antimicrobial use –> Pseudomonas colonization, highly resistant, strong adherence –> Tissue destruction, inflammation, exotoxins, pyocyanin
Pseudomonas: Disease Patterns: Dog & Cat
*Otitis Externa (swimmers, long droopy ears, hair in ear canal) *Lower UTI Pyoderma
Pseudomonas: Disease Patterns: Horse
Metritis/Vaginitis (secondary or contaminated semen) Keratitis & conjunctivitis (after topical steroid-antibiotic mixtures)
Pseudomonas: Case Report:
Boxer dog, multifocal papular deep bacterial pyoderma
Pseudomonas: Disease Pattern: Farmed Mink
Particularly susceptible Hemorrhagic pneumonia & septicemia with high mortalities ~50%
Pseudomonas: Disease Pattern: Bovine
Mastitis (Contaminated intramammary infusion / teat-dipping solution)
Pseudomonas: Disease Pattern: Reptiles
Necrotic stomatitis, pneumonia, septicemia -Poor husbandry
Pseudomonal botryomycosis Presentation
Chronic granulomatous inflammation of skin, subcutis, viscera.
DDx of Pseudomonal botryomycosis
Fungal infections, Staphylococcal botryomycosis
Pseudomonas: Case Study Disease Pattern: Sheep
Fleece Rot -Purulent rhinitis & otitis after showered with contaminated “shower wash”
Pseudomonas: Disease pattern: Humans
Septicemia -Immunocompromised individuals -Burns, leukemia, cystic fibrosis
Pseudomonas: Immunology
No significant specific immune response -Need to decrease risk of secondary infection (hygiene, husbandry)
Pseudomonas: Vaccine?
Possible with extracts of organisms or exotoxin A
What Media should be used to grow Pseudomonas?
Grows on all common media, 4-42C
Does Pseudomonas exhibit hemolysis?
Beta-hemolytic & grows quickly
What do Pseudomonas cultures often smell like?
Corn tortillas, grapes, flowers
Are Pseudomonas spp. Oxidase positive or negative?
Oxidase Positive -Different from enterics!
What are the results of the TSI test with Pseudomonas?
-Red butt & slant (K/K) -Non-fermenter of all three sugars -No Gas Production
What do Pseudomonas spp. pigments do to the appearance of the colonies?
Pigments give darker appearance in areas of confluent growth
What does this image indicate about Pseudomonas grown on MacConkey agar?
That it is Lactose Negative
Pseudomonas: Lab Dx: Trypticase soy agar results
Pyocyanin production
What do these cultures reveal about Pseudomonas spp. pigments?
- Left: Pyocanin pigment production by P. aeruginosa on trypticase soy agar
- Right: Green pigmentation from two water-soluble dyes: blue pyocins & yellow fluorescein
Pseudomonas: Treatment & Control
**ID predisposing factor, eliminate source of organism** -Antimicrobial Therapy (other slide) -Hygeinic Practices -Vaccines may reduce disease severity
Pseudomonas: Antimicrobial Therapy
Very resistant so difficult -Often aids colonization of pseudomonads by eliminating other bacteria -Tetracycline for dog UTI -Gentamicin or tobramycin with cabenicllinin or potentiated ticarcillin
Pseudomonas: Resistance Factors
–Low outer membrane permeability –Multidrug efflux pumps –Production of chromosomally-encoded B-lactamases –Biofilms/Slimes
