Lecture 18 Flashcards
(27 cards)
What is the biocontainment level for Burkholderia mallei?
3
What is the biocontainment level for Burkholderia pseudomallei?
3
Describe the appearance of pseudomonas & non-fermenters
gram negative rods to cocci-bacillus
What is Pseudomonas & Stenotrophomonas famous for?
Difficult to tx opportunistic infections due to intrinsic drug resistance
& pseudomonas is famous for production of alginate biofilm
What is Pseudomonas aeruginosa famous for?
Green colouration
What is the appearance of Pseudomonas aeruginosa on blood agar? (2)
Metallic sheen
Characteristic smell - fruity or wet tortilla chips
Darker colonies
What is the appearance of Stenotrophomonas maltophila?
Foul smelling ammonia like odour
What is the appearance of Pseudomonas aeruginosa on microscopy?
Medium-large gram negative rods
Where is Burkholderia mallei located?
host adapted to equids (doesn’t survive outside the host)
Where is Burkholderia pseudomallei located?
Water & soil of equatorial regions
What are the virulence factors for Pseudomonas aeruginosa? (4)
Elastase - damage to blood vessels & lung tissues, disrupts neutrophil function
Siderophores - ion scavenging giving a characteristic colour
Type III secretion sys - secretion of effector molecules to damage shot tissues or other bacteria
Alginate biofilm - slimy matrix produced by some strains prevents phagocytosis (decrees efficacy of a/b)
Describe the oxidase test
Take a stick & get a colony
Smear colony onto a square of the test
If it is positive it will turn purple in 10-15 secs & if it is neg no colour change
Positive for presence of cytochrome c (component of electron transport chain found in aerobic bacteria)
What diseases does pseudomonas aeruginosa cause? (4)
Pneumonia in farmed milk
Sepsis in poultry
Mastitis in ruminants
Otitis externa in dogs - opportunistic infection
Describe the otitis externa presentation in dogs & horses from pseudomonas aeruginosa
Melting ulcers due to proteolytic enzymes
Sloughing of cornea
How do Pseudomonas fluorescens infections in fish present?
Septicemia of high intensity in aquaculture operations
Fish are lethargic & may have cutaneous lesions
More common in waters with organic pollutants
Why is tx for Pseudomonas fluorescens in fish challenging?
Intrinsic resistance
Since the fish are lethargic, they are less likely to eat the pelleted a/bs so they don’t actually receive the tx
How is Burkholderia mallei transmitted b/w equids?
Ingestion of food or water contaminated by nasal discharges
How does Glanders from Burkholderia mallei present in equids?
Acute
Begins with pyrexia, depression & anorexia
Watery discharge from nostril & coughing
Nodules & ulcers develop on septum & discharge becomes thick
Enlarged lymph nodes
How does Farcy from Burkholderia mallei present in equids?
Cutaneous lesions on limbs & belly
Lymphangitis & lymphadenitis
Nodules may ulcerate
Often fatal within several wks
Not found in NA
How do Burkholderia pseudomallei infections present? & how is it transmitted
Glanders like disease called meliondosis
Broad host range
Contaminated by food or water
Not in NA
How do you collect samples for P. aeruginosa & S. maltophila?
Sites of infection
How do you collect samples for B. mallei?
Discharges for culture
Blood for serology
How does the lab dx Pseudomonas & Stenotrophomonas?
routine test media
easy to identify
How does the lab dx Burkholderia mallei & pseudomallei? (4)
Blood agar & MacConkey agar - colony morph
PCR
Serology
ELSIA
