Lecture 24 - Burkholderia

Question 1

describe the bukholderia genera and list the 4 pathogenic species

Answer 1

• G-ve rods, 70+ species, diverse niches, most non-pathogenic
  1. cepecia complex (BCC)
  2. mallei
  3. pseudomallei
  4. Thailandensis

Question 2

what is the location, disease and resistance of Bulkholderia cepecia complex (BCC)?

Answer 2

• soil, plants (onion rot), mammals = recycling organics
• Cystic fibrosis = nosocomial opportunistic, immunocomp
• contaminated hospital equipment and liquids
• Fatal cepacia syndrome = necrotising pneumonia, resp failure, bacteremia
• Resistant to aminoglycosides, quinolones, polymyxins, beta lactams

Question 3

list the 5 pathogenic components ofBulkholderia cepecia complex (BCC)

Answer 3

1. Cable pilus = epithelial invasion
2. Biofilms
   3.Exopolysac (EPS) cepacian = colonisation and persistence
3. Antimicrobial resistance
4. B cepacia epidemic strain marker (BCESM) on genomic island for metabolism and virulence

Question 4

describe b mallei and the animal/human disease forms it causes

Answer 4

• g-ve aerobic non-motile facultative intracellular
• never isolated from environ
• glanders in horses = swelling below jaw and mucous discharge from nostrils
• humans = nodular lung lesions, fever, septicaemia, death

Question 5

describe the history of b mallei

Answer 5

• hippocrates, aristotle, apsyrtus
• Isolated 1882 by loffler and schutz and french scientists
• 1900 control programs
• WW1 and 2 bioterrorism = germany vs russia, japan, russia vs afghan

Question 6

how does the mallein test for b mallei work? who made it and when?

Answer 6

• glycerin fluid with glanders put in horses eyes = swelling after 1-2 days positive
• russians 1891

Question 7

describe the transmission, location, disease and risk factors of b pseudomallei

Answer 7

• melioidosis = rapid growth, motile, no lesions meant not glanders
• tropical, contaminated soil/air/water esp after rain
• Endemic in SE asia and N aussie
• Cutaneous infection = asymptomatic, acute septicaemia/chronic/latent
• fever, pneumonia, abscesses, life-threatening
• risks = diabetes and renal disease

Question 8

describe the history of b pseudomallei

Answer 8

• whitmore and krishnaswami in morphia addicts in burma 1911
• stanton and fletcher 1932 = melioidosis
• 40% dead in thailand
• australian Currie’s study in QLD/WA over 23yrs
• australia = contaminated wound saline

Question 9

compare and contrast pseudomallei and mallei

Answer 9

• both g-ve safety pin rods, intracellular, 2 chromosomes Chr1 and Chr2
• Pseudo motile vs mallei not
• Pseudo wrinkled on ashdown agar
• Mallei host restricted

Question 10

describe the 3 main virulence factors of burkholderia

Answer 10

1. capusle = CPS of -3)-2-O-acetyl 6-deoxy-β-D-manno-heptopyranose essential for survival and rep in macrophages
2. LPS = heteropolymer of d-glucose and l-talose units ( -3)-β-d-
   glucopyranose-6-deoxy-α-l-talopyranose-)
3. T3SS-3 to escape vesciles + required for full virulence; T3SS-1 and -2 only mallei/thailandensis

Question 11

describe the 5 step intracellular invasion process of burkholderia using the virulence factors involved

Answer 11

1. Invasion = FliC and PilA, BoaA and BoaB, Sap1
2. Phagosome survival = sigma factors, catalase, DpsA
3. Phagosome escape = T3SS
4. Host actin polymerisation = BimA, surface associated protein,
5. Host cell apoptosis and bacterial spread = T6SS