Procedures and Biochemical Identification of Bacteria

  1. What does Catalase test for?
    Catalase, an enzyme that produces water and oxygen from hydrogen peroxide
  2. What organisms does the Catalase test identify?
    • POS - Staphlococcus
    • NEG - Streptococcus
  3. What organism does the Coagulase test identify?
    • POS - Staph aureus (also S. intermedius and S. hyicus)
    • More specific agglutination tests are now performed
  4. What does the PYR test for?
    Detects the enzyme L-pyrrolidonyl arylamidase
  5. What organism does PYR differentiate?
    • NEG - Staph aureus
    • POS - S. lugdensis, S. schleiferi, Strep pyogenes (Group A), and Enterococcus species
  6. What organism does the Bile solubility test identify?
    • Strep pneumoniae
    • In the presence of bile at 37 degrees celcius, colonies will autolyse within 30 min and disappear from the agar surface
  7. What does the Hippurate Hydrolysis test for?
    Detects the bacterial enzyme hipuricase - which hydrolyzes hippurate to glycine and benzoic acid
  8. What organism does the Hippurate hydrolysis test differentiate?
    • POS - Group B Strep, Campylobacter jejuni
    • NEG - Most other beta-hemolytic Streps, Campylobacter species
  9. What does the Oxidase test for?
    Detects chytochrome oxidase that is used in the electron transport system
  10. What organism does the Oxidase test differentiate?
    POS - Pseudomonas species, Neisseria gonorrheae
  11. What does the Indole test for?
    Detects the bacterial enzyme tryptophanase (tryptophan is broken down by tryptophanase into pyruvic acid, ammonia, and indole)
  12. What does the Urease test for?
    Urease breaks down urea to form ammonia (NH3)
  13. What does the Triple sugar iron agar (TSI) test for?
    TSI will show the pattern of glucose, lactose, and sucrose fermentation in addition to H2S and gas production
  14. What organisms does the TSI differentiate?
    • Alkaline slant/alkaline deep (K/K) - Nonfermentor, NOT Enterobacteriaceae
    • Alkaline slant/acid deep (K/A) - Nonlactose and nonsucrose fermenter, glucose fermenter
    • Acid slant/acid deep (A/A) - Lactose and/or sucrose fermenter, and glucose fermenter
    • Black deep, production of H2S gas - production of hydrogen sulfide (H2S) from sulfer-containing molecules in the medium
    • Lead acetate - added to filter paper strips and one end is held in place by the cap.  If H2S gas is produced, a black color will form
  15. What does the TSI result of K/K mean?
    • Nonfermentor
    • NOT Enterobacteriaceae
  16. What does the TSI result of K/A mean?
    • Nonlactose and/or Nonsucrose fermenter
    • Glucose fermenter
  17. What does the TSI result of A/A mean?
    • Lactose and/or sucrose fermenter
    • Glucose fermenter
  18. What does Methyl Red (MR) test for?
    • pH indicator
    • Yellow at acid pH (indicating glucose fermentation)
    • Red is NEG
  19. What does Voges-Proskauer (VP) test for?
    • Detects the metabolism of glucose to acetyl-methyl-carbinol (acetoin)
    • Bacteria are usually MR or VP POS
  20. What does Citrate test for?
    Determines if citrate is used as a sole carbon source
  21. What does ONPG (o-nitrophenyl-beta-D-galactopyranoside) test for?
    • Detects the presence of beta-galactosidase, an enzyme that cleaves ONPG and lactose
    • Test is useful in detecting delayed (late) lactose fermenters that lack or are deficient in beta-galactoside permease
  22. What does the Amino acid degradation test for?
    Detects bacterial enzymes that break down various amino acids
  23. What does the Deaminase reaction test for?
    Detects the ability of an organism to remove the amino group from specific amino acids
  24. What does the Decarboxylation reaction test for?
    Detects the ability of bacteria to remove the carboxyl group from a specific amino acid
  25. What are the reactions in an Amino acid degradation test?
    • Deaminase reaction
    • Decarboxylation reaction
  26. What are some examples of bacterial enzymes that will turn positive for the Amino acid degradation test?
    • Tryptophan (tryptophan deaminase)
    • Lysine (lysine decarboxylase)
    • Ornithine (ornithine dihydrolase)
  27. What does the carbohydrate fermentation test for?
    Detects the ability of bacteria to produce organic acids by the fermentation of various carbs
  28. What does the Nitrate reduction test for?
    Determines the ability of an organism to reduce nitrate (NO3) to nitrite (NO2) and nitrogen gas (N2)
  29. What does the Sherlock Microbial Identification System identify?
    The fatty acid composition of the bacterial cell wall as determined by gas chromatography
  30. How are the fatty acids in mycobacteria identified?
    • The fatty acids in mycobacteria have a larger molecular weight
    • Identified via high-performance liquid chromatography in the Sherlock Mycobacteria Identification System
  31. Name the Gram Stain Reagents, in order
    • Gram Crystal Violet
    • Gram Iodine
    • Acetone-Alcohol Decolorizer
    • Safranin Counterstain
  32. What are key characteristics of Micrococcus?
    • Catalase POS
    • Glucose fermentation NEG
    • Bacitracin SENSITIVE
    • Modified Oxidase POS
  33. Describe the differentiation techniques for Staphlococcus species
    Image Upload 1
  34. Describe the differentiation techniques for Streptococcus species
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  35. Image Upload 3
    Haemophilus parainfluenzae
  36. Image Upload 4
    Haemophilus influenzae
  37. Image Upload 5
  38. Name the H2S producers
    • Salmonella
    • Proteus
    • Citrobacter
  39. Name the positive urease organisms
    • Proteus
    • K. pneumo
    • Providencia
    • Morganella
  40. Name the ONPG positive organism
  41. Name the IMViC patterns for Enterics
    Image Upload 6
  42. Image Upload 7
    • Clostridium perfringens
    • (Reverse CAMP test)
  43. Image Upload 8
    • Positive for Group B beta Strep
    • (Positive CAMP test)
Card Set
Procedures and Biochemical Identification of Bacteria
Biochemical Identification Bacteria and MIDI Inc Identification Systems