9 part 2

• MAC-POSITIVE OXIDASE -POSITIVE ORGANISMS

  • Pseudomonas
  • Burkholderia
  • Achromobacter
  • Chryseobacterium
  • Sphingobacterium
  • Alcaligenes
  • Bordetella (NP)
  • Comamonas
  • Vibrio
  • Aeromonas
  • Plesiomonas
  • Chromobacterium
• Characteristics of MAC-positive oxidase-positive organisms


  • Oxidase positive
  • Catalase positive
  • Grow on MacConkey agar
  • Oxidize glucose
  • NLF
• Cytochrome oxidase

  Participates in electron transport and nitrate metabolic pathways

  
• Reagent used for oxidase test
• Oxidase test procedure


  Rub sample on filter paper impregnated with reagent
• Members of Enterobacteriaceae give negative oxidase test
• Pseudomonas

  • Non-fermentative gram negative bacilli
  • Strictly aerobic
  • Catalase-positive
  • Oxidase-positive
• MacConkey Agar

  Primary selective and differential agar
• MacConkey Agar contains crystal violet dye
• Neutral red


  PH indicator in MacConkey Agar
• Pseudomonads oxidase positive except Burkholderia cepacia and Stenotrophomonas
• Pseudomonas aeruginosa produces slime polysaccharide, endotoxin, and proteases
• Pseudomonas aeruginosa is the species causing the greatest morbidity and mortality today
• Pseudomonas aeruginosa is rarely found as part of the normal flora
• Pseudomonas aeruginosa is ubiquitous in the hospital
• Pseudomonas aeruginosa exists almost anywhere there is moisture
• Agent of "blue pus"

  Produces a blue pigment, PYOCYANIN
• Some strains of Pseudomonas aeruginosa produce other pigments

  Pyoverdin<|>Pyorubin<|>Pyomelanin
• Diseases produced by Pseudomonas aeruginosa

  • UTI
  • Pneumonia
  • Otitis media/externa
  • Eye infection in contact lens wearer
  • Skin lesion
• Pseudomonas aeruginosa causes pneumonia especially in cystic fibrosis patients
• Pseudomonas aeruginosa can cause ecthyma gangrenosum

  
• Biochemical Reactions of Pseudomonas aeruginosa

  • TSI: K/K with a metallic sheen on the slant surface
  • Oxidase and catalase (+)
  • Lysine and ornithine decarboxylase (-)
  • Dihydrolyze arginine
• Pseudomonas maltophilia


  Now Stenotrophomonas maltophilia
• Pseudomonas maltophilia has an ammonia-like odor
• Burkholderia

  • Aerobic, non–spore-forming, gram-negative rods
  • Most are motile
  • Catalase positive
  • Most are oxidase positive
• Burkholderia produces lactose-negative colonies on MacConkey’s agar
• Burkholderia mallei


  Previously Pseudomonas mallei
• Burkholderia mallei causes glanders, a disease of horses transmissible to man
• Burkholderia mallei causes fatal lymphangitis & sepsis in humans

  
• Straus test is used to diagnose glanders
• Burkholderia pseudomallei is also known as Whitmore’s bacillus
• Burkholderia pseudomallei causes melioidosis
• Burkholderia cepacia is a nosocomial pathogen associated with contaminated equipment
• Burkholderia cepacia is most commonly associated with cystic fibrosis patients

  
• Cystic fibrosis patients infected with Burkholderia cepacia have a decreased rate of survival
• Cystic fibrosis

  A chronic, progressive, and frequently fatal genetic disease of the body’s mucus glands

  
• Cystic fibrosis is caused by a defective gene
• Cystic fibrosis causes the body to produce abnormally thick and sticky fluid, called mucus

  
• Mucus in cystic fibrosis clogs the lungs, causing breathing problems

  
• Achromobacter spp can cause bacteremia, meningitis, pneumonia, and peritonitis