1. Disinfection and Sterilization in the Healthcare Environment Richard A. Van Enk, Ph.D., CIC Director, Infection Prevention and Epidemiology, Bronson Methodist Hospital vanenkr@bronsonhg.org 1

2. Objectives You will be able to: 1.Know the terminology and definitions related to disinfection and sterilization 2.Differentiate the various methods used for disinfection and sterilization, with their advantages and disadvantages 3.Review and monitor the disinfection and sterilization processes in your facility 4.Recognize some recent challenges related to disinfection 2

3. Introduction This session will discuss the process by which we make invasive procedures safer by eliminating microorganisms on the devices used in the procedures Contaminated medical devices can cause infections Endoscopy procedures are the highest risk Because of some highly-publicized situations, regulators are looking at this process very closely and we have to work very hard to make it safer 3

4. Terminology of microbial control Sterilization – Destruction of all forms of microbial life – Prions are a special case – Examples of sterilants; autoclave and incineration Disinfection – Destruction of disease-causing microorganisms – Examples of disinfectants; bleach, “quats” Antisepsis – Disinfection safe for use on human tissues – Examples of antiseptics; iodine, alcohol, peroxide 4

5. Terminology of microbial control Sanitize – Microbial control to public health standards – Sanitizers prevents epidemics, mainly foodborne and other gastrointestinal infections – Used in bathroom and kitchen environments Decontaminate – Make safe to handle “-cide” denotes killing “-stat” denotes inhibition 5

6. Factors affecting microbial killing Microbial Factors – Microorganisms vary in susceptibility to killing and are ranked in six or seven groups – Antimicrobial agents are graded by the EPA according to the microbial rank they can kill – Log-phase bacteria are most susceptible to killing, stationary are most resistant Environmental Factors – Temperature, pH, and presence of organic matter protecting the microorganisms 6

7. Ranking of microorganisms in resistance to killing 7

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9. Kinetics of microbial death Like microbial growth, the rate of microbial death under constant conditions is constant and logarithmic and takes time Expressed as the decimal reduction time (D) – The time needed to kill 90% of the population – Example: If D is one minute, it takes one minute to go from 1000 cells to 100, two minutes to go to 10, three minutes to go to 1, four minutes to (theoretically) kill them all The fewer the microorganisms you start with, the shorter the time it takes to kill them 9

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11. Microbial killing by heat Different forms of heat are used for different applications Dry heat oxidizes (burns) the cell components Heat with moisture hydrolyzes chemical bonds Hydrolysis kills much faster than oxidation Positive features of heat; – Effective, fast, easy, reliable, cheap, non-toxic Negative features of heat; – Heat or moisture may damage some products (paper, plastic, organic chemicals) 11

12. Conventional autoclave Sterilizes (kills endospores) Uses steam under pressure Uses 121°C at 15 pounds per square inch (psi) for 15 minutes For items that can get wet Items are wrapped in paper and placed in metal caskets to protect them 12

13. The autoclave; flash sterilization When an instrument in the OR needs to be re-sterilized quickly and you don’t have time to take it through the whole reprocessing process – Dropped on the floor – Needed for the next case The item can be sterilized in a little autoclave in the OR and used immediately High risk; not inspected, used wet, no QC Regulators do not like it at all 13

14. Gas sterilizers Ethylene oxide gas – Steris Isomedix, 3M Steri-vac – Denatures proteins and DNA – Used for some heat- sensitive hospital instruments – Explosive, toxic, slow H 2 O 2 Plasma sterilizers – Sterrad®, others – Generates superoxide radicals in vapor form – Can replace autoclaves in some applications, not others 14

15. Pasteurization First discovered by Louis Pasteur A disinfectant process often used on medical devices for high level disinfection (not sterilization) – Endoscopes that go into the respiratory, genital or GI tract – Respiratory care parts – Anesthesia equipment – Vaginal probes Uses combinations of heat and moisture to kill microorganisms – Usually about 70° C for 30 minutes Item becomes safe but not sterile 15

16. Chemical disinfectants/sterilants Registered by the EPA (disinfectants) and FDA (sterilants) We use the Spaulding system (Earle H. Spaulding) of critical, semi-critical and non-critical disinfection in hospitals – Sterilants produce sterility, for critical items – High-level disinfectants kill all pathogens, for semi-critical – Intermediate-level disinfectants kill mycobacteria and below on the killing scale – Low-level disinfectants kill less resistant microorganisms, for non- critical items – The same chemical can be used as a sterilant or high-level disinfectant depending on the time of exposure or strength Must be used according to directions – Sensitive to temperature, pH, dilution, diluent, time, organic background 16

17. Chemical disinfectant classes Alcohols (ethanol and isopropanol) – Antiseptics – Dissolves lipids, disrupts membranes, proteins – Usually used as a 70% concentration in water – Example; hand sanitizer, wiping skin before an injection Halogens (iodine and chlorine) – Oxidize proteins – Iodine as tincture (with alcohol) or iodophor (a chemical that controls the release of the halogen) – Chlorine as 0.5 ppm in water (bleach) – Example; Betadine 17

18. Chemical disinfectant classes Phenol and Phenolics – Damages plasma membranes – Has residual activity on surfaces – Powerful, long-acting, but can damage some materials; was used in operating rooms, not used in hospital anymore Aldehydes – Inactivates proteins and DNA – Examples: formaldehyde, glutaraldehyde – Highly effective but classified as hazardous – Used as a general purpose high-level disinfectant 18

19. Chemical disinfectant classes Quaternary ammonium compounds (“quats”) – Benzalkonium chloride - Zephiran – Disrupts the cell membrane – General purpose low-level disinfectant, applied with a squirt bottle, left on for 10 minutes Metals – Combine with -SH groups, denature proteins – Examples: silver nitrate ointments, mercury (mercurochrome), copper – Used on burns; doesn’t sting or irritate skin 19

20. Common hospital chemical disinfectants/sterilants Peracetic acid/hydrogen peroxide (Acecide®, Endospor®, Peract®) for high-level Glutaraldehyde (old Cidex®, MetriCide®) for high-level Hydrogen peroxide (Clorox, STERRAD) for intermediate- level Ortho phthalaldehyde (OPA, new Cidex®) for high level Peracetic acid (Soluscope 3® endoscope processor) for high-level Improved peroxide (Oxivir TB®, Chlorox Healthcare®) spray for low-level 20

21. Types of devices to be reprocessed Flexible endoscopes ERCP scopes Cystoscopes Vaginal probes Laryngoscope blades Bronchoscopes All made of materials that you cannot autoclave 21

22. The reprocessing process; high-level disinfection 1.Cleaning 2.Disinfection 3.Rinsing 4.Drying 5.Storage Inspection at each step 22

23. The reprocessing process; cleaning The most important step in the reprocessing of medical items and equipment is not disinfection or sterilization The most important step is cleaning – Removal of organic material (bioburden, biofilm) using water and detergent or enzymatic cleaner plus scrubbing (friction) with brushes – You cannot disinfect or sterilize something that is dirty – Example; you must presoak dirty items at the point of use to prevent drying of bioburden in transport 23

24. The reprocessing process; cleaning In the reprocessing area, there are some machines that can clean some instruments – Some claim to be washer-sterilizers – Ultrasonic cleaner machines How clean is clean? – There are no practical ways to measure cleaning AAMI says <6.4 ug of protein per cm 2 is clean How do you measure that? Current controversy; should cleaning be done by non-specialists at the point of use or by specialists in the central reprocessing area? 24

25. The reprocessing process; disinfection 25 Manual chemical – After cleaning, the scope is soaked in a high-level disinfectant – A very error-prone process – Temperature, expiration date, concentration, time of exposure, PPE all must be perfect – Requires special air handling

26. The reprocessing process; disinfection Automated chemical – Olympus OER-Pro, Steris System 1 and Reliance, Evotech, Soluscope 3 – Machines are designed for each scope, hook up to each channel, run the chemical through, rinse, dry – More reliable than manual, but expensive, not all scopes are compatible with each machine 26

27. The reprocessing process; storage 27 Flexible endoscopes must be stored vertically in a clean cabinet – Prevents water drops in the channels, microbial growth – Absolutely cannot throw them in a drawer or put them in the box they were shipped in – Shown; regular case and drying case that forces dry air through the channels

28. The reprocessing process; sterilization 1.Cleaning 2.Inspection 3.Packaging 4.Sterilization 5.Sterile Storage 6.Quality indicators 28

29. Challenges to reprocessing Many of the devices have internal channels Materials compatibility Failure of the device over time; inspection No good way to scrub some parts Human factors; personnel are not trained, certified, or paid well and work in poor conditions Desired turnaround time does not allow for adequate reprocessing Reprocessing machines are expensive 29

30. Challenges to reprocessing Ambulatory surgery centers and other off-site settings No good way to do quality control Manufacturers instructions for use do not work Reliance on flash sterilizing rather than buying enough instruments Infection preventionist is not involved enough Transport of contaminated instruments Not presoaking instruments Reprocessing single-use devices 30

31. CDC Guidelines 2008 Guideline for Disinfection and Sterilization in Healthcare Facilities – http://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_N ov_2008.pdf http://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_N ov_2008.pdf Association for the Advancement of Medical Instrumentation – http://www.aami.org/ http://www.aami.org/ Interim Protocol for Healthcare Facilities Regarding Surveillance for Bacterial Contamination of Duodenoscopes after Reprocessing – http://www.cdc.gov/hai/pdfs/cre/interim-duodenoscope- surveillance-Protocol.pdf http://www.cdc.gov/hai/pdfs/cre/interim-duodenoscope- surveillance-Protocol.pdf 31