M: Sterilization 2 - Week 8 Flashcards
Name and describe 2 new techniques used for chemical based sterilisation?
What makes these techniques better than previous ones?
Sterrad process: uses hydrogen peroxide as the sterilizing agent that breaks down to h2o and O2
Sterris process: uses peracetic acid as the sterilizing agent. However you need to rinse the article with sterile water after it’s been sterilised with paracetic water
— these techniques are far less toxic and are still effective
Explain process monitoring
Check that the sterilisation process has been effective by measuring and assessing many parameters
Name 3 parameters assessed in process monitoring
- Physical indicators (temp, time, pressure)
- Chemical indicators (sterilisation strip that changes colour, autoclave tape)
- Biological indicators (spore strips)
What is the best way to make the sterilisation process more effective?
Prevent problems in the first place by checking the critical points in the process. Then you are less likely to have unsterilised loads coming out of the autoclave
What does HACCP stand for?
Hazard Analysis Critical Control Points
When is disinfection often used and what does this achieve?
Before sterilisation. It reduces the initial load of organisms originally in the article and therefore reduces the time it takes to reach the sterility assurance level desired
Name 3 methods of disinfection
- simple washing and cleaning
- hot water or steam for shorter times
- chemical disinfectants
Name 3 purposes of hand washing.
- remove transient bacteria and debris
- reduce resident flora
- inhibit rapid rebound of bacteria growth
True or false: hand washing can completely remove resident flora
False. It can only reduce it
Describe the features of an ideal hand wash:
- affects broad spectrum of microbes
- non irritant and non allergenic
- has rapid and residual action
Which disinfectants work best?
Aldehydes and halogens because they have a broad spectrum and biocidal action
How good of a disinfectant is chlorine? Explain
Poor. Chloride does not work at cold temperatures and it needs low organic activity
Which disinfectant can cause contact dermatitis?
Iodophors, which is a halogen disinfectant
For the following chemical disinfectants, state the dilation used to disinfect tonometers and gonioscopy prisms:
A) Chlorine
B) Hydrogen Peroxide
C) Alcohols
A: Chlorine - 0.4-0.5% solution
B: Hydrogen Peroxide - 3% solution
C: Alcohols - 70% solution
What disinfectants should be made fresh when you use them? Why?
Halogens and Hydrogen peroxide. Because they are not stable and solutions will only last a short time (around a day or so)
What affects the disinfectant action of chlorine? List 3 influencing factors
- temperature
- pH
- organic material
Out of the following disinfectants, which are active against spores, cysts and enveloped viruses?
- Halogens
- Alcohols
- Phenols
- Chlorhexidine (biguanide)
Halogens
The rest are all not active against spores. Alcohols are not active against cysts too while phenols and chlorhexadine are both not active against non-enveloped viruses
What factors affect the efficiency of a disinfectant? List 5 factors
- concentration
- contact time
- temperature
- pH
- presence of organic material
What affects your choice of disinfectant? List 4 factors
- type and state of microorganisms
- contact time available
- physical nature of surface or article
- allowable concentration
How essential is pre-cleaning prior to disinfection?
Very
When are strong oxidising agents like hydrogen peroxide, chlorine dioxide and peracetic acid considered “sporicidal”?
When they are at a high concentration
What are halogens active against? (4)
Active against:
- most bacteria and viruses, including HIV and HIB
- spores and cysts
When would you use iodophor as an alternative to chlorhexidine?
When broader spectrum of bactericidal and soricidal action needed
How would you describe the spectrum of action for strong oxidizing agents like hydrogen peroxide, chlorine dioxide and peracetic acid?
Reasonably broad spectrum of action
What can affect the activity of chlorhexadine?
anions and soap
What are QACs? What does QAC stand for?
Quaternary Ammonium Compounds (e.g. cetrimide)
- are cationic surface-active disinfectants
What are QACs useful for?
Useful for gram positive bacteria and non-enveloped viruses, otherwise limited or no activity
Is 0.9% saline a disinfectant?
NO!
When cleaning contact lenses, what does rubbing them accomplish?
Rubbing removes biofilms. Biofilms are much more resistant to disinfectants compared to individual bacteria
