Mannitol Salt Agar (MSA) Bacterial Growth Medium: Microbiology Lab Tutorial — Transcript

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1. 0:01in this video I'll teach you the basics
2. 0:04of manitol salt specialized bacterial
3. 0:07growth
4. 0:28medium
5. 1:39here are some more examples of
6. 1:40halophilic salt loving bacteria growing
7. 1:43on manitol salt
8. 1:47auger here are two nasal samples plated
9. 1:51on manatal salt
10. 1:53augur let's first examine the plate on
11. 1:56the
12. 1:57left there is growth so so we know these
13. 2:00are halophilic
14. 2:02bacteria we can also see that the growth
15. 2:05on this plate has triggered the pH
16. 2:07sensitive Dy to change color meaning
17. 2:10that the bacteria on this plate are
18. 2:12manitol
19. 2:14fermenters so that is what I've learned
20. 2:16about the bacteria growing on that left
21. 2:18plate from The Selective and
22. 2:21differential properties of manitol salt
23. 2:25AER I can also sometimes get additional
24. 2:28information about the bacteria growing
25. 2:30on my plate by looking at their colony
26. 2:35morphology Colony morphology refers to
27. 2:38what each different type of bacteria
28. 2:41looks like when growing in a visible
29. 2:43Colony on the surface of the
30. 2:52augur when I look at the colony
31. 2:55morphology of the bacteria growing on
32. 2:57the left plate I see two main types of
33. 3:03bacteria towards the top of the plate
34. 3:05above the word nose are some larger
35. 3:08creamy yellow colonies most likely
36. 3:13micrococcus and starting on the right
37. 3:15Edge then extending towards the center
38. 3:17of the plate are these tiny punctiform
39. 3:20colonies these are the bacteria that
40. 3:23change the color of the plate these are
41. 3:25the bacteria that ferment manitol and
42. 3:28they are staak
43. 3:32orus the plate on the right also shows
44. 3:36growth which means there are halophiles
45. 3:38or salt loving bacteria growing on that
46. 3:42plate but the bacteria growing on this
47. 3:45plate are not manitol fermentors we know
48. 3:48that because the growth did not trigger
49. 3:51that change in the color of the medium
50. 3:53from pink to Yellow this medium remained
51. 3:56pink indicating non manitol fermenters
52. 4:00most typically normal flora like sta
53. 4:03lakus
54. 4:06epidermus here is staf cacus epidermus
55. 4:10normal flora that will grow on manitol
56. 4:13salt augur but not change the color of
57. 4:16the
58. 4:17medium here's staff appy from two nasal
59. 4:20samples growing in their characteristic
60. 4:22punctiform small white creamy colonies
61. 4:25and here's staff appy on manitol salt
62. 4:29auger
63. 4:30these bacteria were streak
64. 4:36plated on this plate we also see the
65. 4:38growth of halophiles but in this case
66. 4:42the bacteria triggered the pH sensitive
67. 4:44die to change color that means that we
68. 4:47have manitol fermenters stacus orius a
69. 4:52pathogen here's a nasal sample plate
70. 4:55prepared by a pair of Lab
71. 4:57Partners the sample on the left
72. 4:59indicates pathogen stacus orus a
73. 5:04halophile that will grow on manitol salt
74. 5:07augur and ferment manitol triggering
75. 5:10that pH sensitive die to change
76. 5:13color the sample on the right indicates
77. 5:16stacus epidermus which is normal flora
78. 5:20that is halophilic it will grow on
79. 5:22manitol salt augur but does not ferment
80. 5:24manital so there is no change in the
81. 5:26color of the
82. 5:28augur
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