Biochemical Tests and             Diagnostic Media• Labs #6 (white) and #7 (green)           white• Overall scheme: Lab #6...
SIM medium: Motility test   POSITIVE:       NEGATIVE:Organism moves     Organism does NOTaway from stab     move away from...
SIM medium: Sulfur testH2S-NEGATIVE:       H2S-POSITIVE:   no black        black precipitate  precipitate          formed ...
Simmon’s citrate agar slant negative            positive
Diagnostic Media• Mannitol salt agar• Eosin methylene blue (EMB) agar• Brilliant green agar
Selective medium   Selects for the GROWTH of some organisms and inhibits the growth of            other organisms.   i.e. ...
Differential medium  Differentiates between one type oforganism and another type of organism. Different types of organism ...
Mannitol salt agarStaphylococcus                                         Serratia    aureus                               ...
Mannitol salt agar      Differential mediumDifferentiates among staphylococci
Mannitol salt agar      Differential mediumDifferentiates among staphylococci
Mannitol salt agar                                                  Staphylococcus                                        ...
Mannitol salt agar                                                         StaphylococcusMicrococcus does not             ...
Levine Eosin-Methylene Blue (EMB)                  Agar  Gram negatives     (growth)  Gram positive(growth inhibited)     ...
Levine Eosin-Methylene Blue (EMB)                AgarLactose          Nonlactosefermenter        fermenters            DIF...
High acid producers on EMB             e.g. E. coliblue-black colonies or metallic sheen
Levine Eosin-Methylene Blue (EMB)                  Agar Lactose fermenter       Non-lactose fermenter  (high acid producer...
Brilliant Green Agar SELECTIVE    •   Growth of all gram positive and          many gram negative bacteria          inhibi...
Brilliant Green Agar          DIFFERENTIALDifferentiates lactose fermenters from        nonlactose fermenters
Brilliant Green AgarLactose fermenter   Non-lactose fermenter E. coli                     Salmonella
Catalase Test Many bacteria produce the enzyme catalase.           catalaseH2O2                  H2O       +     O2hydroge...
Catalase Test                     bubbles (gas)Catalase positive organism
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Diff mediasv

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Diff mediasv

  1. 1. Biochemical Tests and Diagnostic Media• Labs #6 (white) and #7 (green) white• Overall scheme: Lab #6 (white) , last page white
  2. 2. SIM medium: Motility test POSITIVE: NEGATIVE:Organism moves Organism does NOTaway from stab move away from stab
  3. 3. SIM medium: Sulfur testH2S-NEGATIVE: H2S-POSITIVE: no black black precipitate precipitate formed formed
  4. 4. Simmon’s citrate agar slant negative positive
  5. 5. Diagnostic Media• Mannitol salt agar• Eosin methylene blue (EMB) agar• Brilliant green agar
  6. 6. Selective medium Selects for the GROWTH of some organisms and inhibits the growth of other organisms. i.e. Some organisms grow on a selective mediumwhereas others do not grow (or do not grow well) on that same medium.
  7. 7. Differential medium Differentiates between one type oforganism and another type of organism. Different types of organism look different from each other when grown on differential media.
  8. 8. Mannitol salt agarStaphylococcus Serratia aureus marcescens grows does not grow Selective medium High salt (NaCl) concentration in medium favors organisms that tolerate high salt concentration, e.g. Staphylococcus.
  9. 9. Mannitol salt agar Differential mediumDifferentiates among staphylococci
  10. 10. Mannitol salt agar Differential mediumDifferentiates among staphylococci
  11. 11. Mannitol salt agar Staphylococcus ferments mannitol (yellow) Differential mediumDifferentiates among staphylococci: • pathogenic Staphylococcus species ferment mannitol to produce acid (yellow medium)
  12. 12. Mannitol salt agar StaphylococcusMicrococcus does not ferments ferment mannitol mannitol (pink) (yellow) Differential medium Differentiates among staphylococci: • pathogenic Staphylococcus species ferment mannitol to produce acid (yellow medium) • less pathogenic Micrococcus (a staphylococcus)
  13. 13. Levine Eosin-Methylene Blue (EMB) Agar Gram negatives (growth) Gram positive(growth inhibited) SELECTIVE MEDIUM
  14. 14. Levine Eosin-Methylene Blue (EMB) AgarLactose Nonlactosefermenter fermenters DIFFERENTIAL MEDIUM
  15. 15. High acid producers on EMB e.g. E. coliblue-black colonies or metallic sheen
  16. 16. Levine Eosin-Methylene Blue (EMB) Agar Lactose fermenter Non-lactose fermenter (high acid producer: black colonies) Gram positive(growth inhibited) Lactose fermenter (low acid producer: pink colonies)
  17. 17. Brilliant Green Agar SELECTIVE • Growth of all gram positive and many gram negative bacteria inhibited • Growth of many Salmonella species occursDIFFERENTIAL
  18. 18. Brilliant Green Agar DIFFERENTIALDifferentiates lactose fermenters from nonlactose fermenters
  19. 19. Brilliant Green AgarLactose fermenter Non-lactose fermenter E. coli Salmonella
  20. 20. Catalase Test Many bacteria produce the enzyme catalase. catalaseH2O2 H2O + O2hydrogen oxygenperoxide (gas)
  21. 21. Catalase Test bubbles (gas)Catalase positive organism
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