Good Microbiological Practices and Procedures (GMPP) 5: autoclaves — Transcript

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1. 0:05of all the methods surveillance to
2. 0:08decontaminate laboratory waste
3. 0:10autoclaving is one of the easiest and
4. 0:13most effective autoclaving combines heat
5. 0:16steam and high pressure to kill
6. 0:19biological agents it's important to note
7. 0:23that some biological agents are more
8. 0:25robust than others for example bacterial
9. 0:29spores and prions pretreatment with
10. 0:32disinfectant increased temperature
11. 0:34pressure and contact time may be
12. 0:37required to neutralize such agents
13. 0:40different combinations of temperature
14. 0:43and contact time are used depending on
15. 0:46the types of materials being sterilized
16. 0:48a fundamental requirement is the need
17. 0:51for the heat to penetrate throughout a
18. 0:53load dense loads or ones with high
19. 0:57organic content are hardest to sterilize
20. 1:00because they resist the penetration of
21. 1:03the steam and heat glassware is the
22. 1:07easiest because there is a lower load
23. 1:10density and it traps heat within the
24. 1:12contents steam is generated at the
25. 1:16beginning of a cycle delivered either by
26. 1:19boiling water in a reservoir or
27. 1:21injecting piped steam depending on the
28. 1:24type of autoclave and facilities
29. 1:26available the autoclave cycle consists
30. 1:31of three phases in the heat up phase
31. 1:35temperature and pressure are raised to
32. 1:38preset values some autoclaves create a
33. 1:42partial vacuum during this phase to help
34. 1:45steam penetrate the load
35. 1:47during the dwell time or holding time
36. 1:50the autoclave maintains a constant
37. 1:53temperature and pressure to ensure
38. 1:55sterilization
39. 1:58during the cooling down phase heat and
40. 2:01pressure are allowed to fall to ambient
41. 2:03levels in some autoclaves there may be
42. 2:06an assisted cooling function to reduce
43. 2:08the overall cycle time
44. 2:12some typical autoclave parameters are
45. 2:16115 Celsius for 30 minutes 121 Celsius
46. 2:21for 15 minutes or a hundred and 15
47. 2:24Celsius for 60 minutes these are all
48. 2:27validated to achieve sterilization of
49. 2:30most biological agents assuming
50. 2:32sufficient penetration but spores and
51. 2:35prions may require higher temperatures
52. 2:38and all pretreatment the dwell time may
53. 2:41be increased to ensure sufficient
54. 2:43penetration in denser loads or generally
55. 2:46as an additional precautionary measure
56. 2:50in modern autoclaves there is usually a
57. 2:53safety thermal lock which prevents the
58. 2:56lid or door being opened at scalding
59. 2:58temperature if the autoclave has a
60. 3:02printout that displays the temperature
61. 3:04it may display the sterilization cycle
62. 3:07as a graph or as the temperatures
63. 3:10actually achieved these may fluctuate
64. 3:13slightly above and below the set
65. 3:15temperature but this is normal as the
66. 3:18heater pulses so long as it achieves the
67. 3:20average over the time period when the
68. 3:23autoclave is serviced this will be
69. 3:25checked and validated it's important to
70. 3:29note that when autoclaving bottles
71. 3:31either full or empty it's advisable to
72. 3:34loosen the caps to ensure that pressure
73. 3:37differentials don't cause them to break
74. 3:40waste to be autoclaved must be packaged
75. 3:43such that steam can penetrate the entire
76. 3:46load plastic autoclave bags must be
77. 3:49loosely taped ideally with indicator
78. 3:52tape and not tightly bound these should
79. 3:55then be placed in autoclave herbal boxes
80. 3:58to contain their contents as the plastic
81. 4:01bags may melt and leak some packaging
82. 4:04such as paper autoclave bags often used
83. 4:07for sterilizing small items like steel
84. 4:10coupons and spatulas is designed so that
85. 4:13the steam will permeate through the
86. 4:15packaging which remains completely
87. 4:17sealed appropriate PPE such as a
88. 4:24laboratory coat and gloves and eye
89. 4:27protection for handling liquids should
90. 4:29be worn when handling waste and when
91. 4:32transporting waste to the autoclave
92. 4:35items should not be stacked on top of
93. 4:37one another as this prevents steam
94. 4:40penetration unless there is shelving or
95. 4:43baskets to create space between the
96. 4:45items
97. 4:48the autoclave cycle should be verified
98. 4:51before first use and periodically
99. 4:54thereafter to make sure the cycle
100. 4:57parameters are effectively killing the
101. 4:59microorganisms handled in your
102. 5:01laboratory some autoclaves can be fitted
103. 5:05with load sensing probes which can be
104. 5:08inserted into the center of a dense load
105. 5:10to monitor temperature and verify that
106. 5:13sterilization temperature has been
107. 5:15achieved chemical indicators such as
108. 5:19autoclave tape use heat sensitive ink
109. 5:22that changes color when it reaches a set
110. 5:25temperature this is a useful indicator
111. 5:27but it's only checking the temperatures
112. 5:30on the outside surfaces not the contents
113. 5:32and it doesn't tell you if the required
114. 5:35pressure and dwell time were achieved
115. 5:38another method of verification is to put
116. 5:42a broth culture of an appropriate
117. 5:43biological agent through the autoclave
118. 5:46cycle if subsequent attempts to grow the
119. 5:49biological agent from the autoclave
120. 5:51broth fail to produce growth then the
121. 5:54autoclave cycle has been shown to be
122. 5:56effective biological indicators such as
123. 6:02spore strips or discs may also be used
124. 6:04to provide verification there Oh bust
125. 6:08nature means that if they are killed by
126. 6:10the autoclave cycle then most other
127. 6:12biological agents will be killed by the
128. 6:15same cycle spore strips or discs are
129. 6:19generally placed at various locations
130. 6:21within the autoclave to ensure that all
131. 6:24areas reach the required parameters they
132. 6:27can also be placed within a typical
133. 6:29autoclave load although it can prove
134. 6:32difficult to extract them from the load
135. 6:34when the autoclave cycle is complete the
136. 6:39recovered strips or discs are placed in
137. 6:41liquid broth and incubated
138. 6:45no growth after a set time period such
139. 6:49as 48 hours would mean the autoclave
140. 6:51cycle is effective autoclaves must be
141. 6:56well-maintained
142. 6:57to make sure they perform as required
143. 7:00this increases productivity and reduces
144. 7:03downtime routine in use maintenance
145. 7:07includes making sure any water
146. 7:10reservoirs are kept clean and filled
147. 7:12with water and are regularly checked for
148. 7:15signs of wear and tear such as corrosion
149. 7:18the temperature profile of each
150. 7:20autoclave load must be checked to make
151. 7:23sure that the sterilization conditions
152. 7:25have been achieved this is important as
153. 7:28if the waste has not been sterilized
154. 7:31other people handling the waste post
155. 7:34autoclaving are at risk of exposure and
156. 7:37subsequent potential infection
157. 7:42autoclaves should be serviced at least
158. 7:44annually and tested by a specialist
159. 7:47contractor who can make sure the set
160. 7:49temperature and pressure cycles are
161. 7:51accurate and check the overall condition
162. 7:54of the autoclave this is important
163. 7:57because of the high pressures at which
164. 7:59they operate because of these high
165. 8:02pressures in some countries it is also a
166. 8:04statutory requirement for autoclaves to
167. 8:07be tested by an independent pressure
168. 8:10systems Assessor if there is a power
169. 8:14failure or if the autoclave breaks down
170. 8:17during a sterilization cycle the
171. 8:19autoclave should not be opened straight
172. 8:21away instead attempts should be made to
173. 8:25fix the autoclave and repeat the cycle
174. 8:30only if it's not possible to restart
175. 8:32should the autoclave be open and the
176. 8:35incompletely autoclaved waste removed
177. 8:39the waste removed from the autoclave may
178. 8:43still contain live biological agents so
179. 8:46you will need to wear the same PPE that
180. 8:48you used when loading the autoclave this
181. 8:52waste must be suitably contained for
182. 8:54storage and should be labeled to
183. 8:57indicate that it is an autoclave waste
184. 9:01if the waste needs to be sent elsewhere
185. 9:04for sterilization it will need to be
186. 9:07suitably packaged for transportation in
187. 9:09accordance with the UN model regulations
188. 9:14once the waste has been removed if
189. 9:17access to the autoclave chamber is
190. 9:19required for maintenance or repair the
191. 9:21inside of it should be wiped down with
192. 9:24an effective disinfectant in summary
193. 9:29good practices when using autoclaves
194. 9:32include wear appropriate PPE when
195. 9:36loading and unloading verify cycle
196. 9:40parameters are being achieved by
197. 9:42checking temperature profiles and use
198. 9:45load sensing probes where possible
199. 9:48ensure steam penetration by taping bags
200. 9:52loosely and not tightly packing or over
201. 9:55filling the autoclave loosened lids of
202. 9:59bottles before starting the autoclave
203. 10:02use autoclave boxes or tins to contain
204. 10:06any melted items or liquids use chemical
205. 10:11and biological indicators to check that
206. 10:14cycle parameters are effective for the
207. 10:16biological agents you are handling have
208. 10:20a regular maintenance program in place
209. 10:28[Music]
210. 10:32you