STERILIZATION AND DISINFECTION

1. STERILIZATION AND DISINFECTION Meral Sonmezoglu, MD. Assoc Professor of Infectious Dıseases

3. DEFINITIONS • Decontamination: Removal of disease-producing m.o. to leave an item • Disinfection: Inactivation of disease-producing m.o. (not destroy) • Sterilization: Destruction of all forms of microbial life (bacteria, viruses, spores, fungi) • Sanitation: A process that reduces mo on an inanimate object to a level of below infectious hazard

4. Disinfection—The process of microbial inactivation that eliminates virtually all recognized pathogenic microorganisms, but not necessarily all microbial forms (e.g., spores) • Sterilization—The use of physical or chemical procedures to destroy all microbial life, including large numbers of highly resistant bacterial endospores. Procedures include— • Steam sterilization • Heat sterilization • Chemical sterilization

5. Efficacy of Disinfection/Sterilization • Cleaning of the object • Organic and inorganic load present • Type and level of microbial contamination • Concentration of and exposure time to disinfectant/sterilant • Nature of the object • Temperature and relative humidity

6. Decreasing Order of Resistance of Microorganisms to Disinfectants/Sterilants Prions Spores Mycobacteria Non-Enveloped Viruses Fungi Bacteria Enveloped Viruses

7. Disinfection and Sterilization An object will be disinfected depended on the object’s intended use. CRITICAL - objects which enter normally sterile tissue or the vascular system or through which blood flows should be sterile. SEMICRITICAL - objects that touch mucous membranes or skin that is not intact require a disinfection process (high-level disinfection[HLD]) that kills all microorganisms but high numbers of bacterial spores. NONCRITICAL -objects that touch only intact skin require low-leveldisinfection.

8. Processing “Critical” Patient Care Objects Classification: Critical objects enter normally sterile tissue or vascular system, or through which blood flows. Object: Sterility. Level germicidal action:Kill all microorganisms, including bacterial spores. Examples: Surgical instruments and devices; cardiac catheters; implants; etc. Method: Steam, gas, hydrogen peroxide plasma or chemical sterilization.

9. Critical Objects • Surgical instruments • Cardiac catheters • Implants

10. Chemical Sterilization of “Critical Objects” Glutaraldehyde (> 2.0%) Hydrogen peroxide-HP (7.5%) Peracetic acid-PA (0.2%) HP (1.0%) and PA (0.08%) HP (7.5%) and PA (0.23%) Glut (1.12%) and Phenol/phenate (1.93%) _______________________________________________ Exposure time per manufacturers’ recommendations

12. Processing “Semicritical” Patient Care Objects Classification: Semicritical objects come in contact with mucous membranes or skin that is not intact. Object: Free of all microorganisms except high numbers of bacterial spores. Level germicidal action:Kills all microorganisms except high numbers of bacterial spores. Examples: Respiratory therapy and anesthesia equipment, GI endoscopes, thermometer, etc. Method: High-level disinfection

13. Semicritical Items • Endoscopes • Respiratory therapy equipment • Anesthesia equipment • Endocavitary probes • Tonometers • Diaphragm fitting rings

14. High Level Disinfection of “Semicritical Objects” Exposure Time > 12 m-30m, 20oC Germicide Concentration_____ Glutaraldehyde > 2.0% Ortho-phthalaldehyde (12 m) 0.55% Hydrogen peroxide* 7.5% Hydrogen peroxide and peracetic acid* 1.0%/0.08% Hydrogen peroxide and peracetic acid* 7.5%/0.23% Hypochorite (free chlorine)* 650-675 ppm Glut and phenol/phenate** 1.21%/1.93%___ *May cause cosmetic and functional damage; **efficacy not verified

15. Processing “Noncritical” Patient Care Objects Classification: Noncritical objects will not come in contact with mucous membranes or skin that is not intact. Object: Can be expected to be contaminated with some microorganisms. Level germicidal action:Kill vegetative bacteria, fungi and lipid viruses. Examples: Bedpans; crutches; bed rails; EKG leads; bedside tables; walls, floors and furniture. Method: Low-level disinfection

16. Low-Level Disinfection for “Noncritical” Objects Exposure time > 1 min Germicide Use Concentration Ethyl or isopropyl alcohol 70-90% Chlorine 100ppm (1:500 dilution) Phenolic UD Iodophor UD Quaternary ammonium UD _____________________________________ UD=Manufacturer’s recommended use dilution

17. Disinfectants for Surface Disinfection • Noncritical Surfaces • Medical equipment surfaces (BP cuff, stethoscopes) • May frequently become contaminated with patient material • Repeatedly touched by health care personnel • Disinfectant/detergent should be used • Housekeeping surfaces (bed rails, bedside tables) • May play a theoretical but less significant role in diseases transmission • Disinfectants/detergents may be used (II) and detergents (non-patient care areas)

18. Sterilization and Disinfection of Patient Care Items

19. Critical Instruments • Penetrate mucous membranes or contact bone, the bloodstream, or other normally sterile tissues (of the mouth) • Heat sterilize between uses or use sterile single-use, disposable devices • Examples include surgical instruments, scalpel blades, periodontal scalers, and surgical dental burs

20. Semi-critical Instruments • Contact mucous membranes but do not penetrate soft tissue • Heat sterilize or high-level disinfect • Examples: Dental mouth mirrors, amalgam condensers, and dental handpieces

21. Noncritical Instruments and Devices • Contact intact skin • Clean and disinfect using a low to intermediate level disinfectant • Examples: X-ray heads, facebows, pulse oximeter, blood pressure cuff

22. Instrument Processing Area • Use a designated processing area to control quality and ensure safety • Divide processing area into work areas • Receiving, cleaning, and decontamination • Preparation and packaging • Sterilization • Storage

23. Automated Cleaning • Ultrasonic cleaner • Instrument washer • Washer-disinfector

24. Manual Cleaning • Soak until ready to clean • Wear heavy-duty utility gloves, mask, eyewear, and protective clothing

25. Preparation and Packaging • Critical and semi-critical items that will be stored should be wrapped or placed in containers before heat sterilization • Hinged instruments opened and unlocked • Place a chemical indicator inside the pack • Wear heavy-duty, puncture-resistant utility gloves

26. Heat-Based Sterilization • Steam under pressure (autoclaving) • Gravity displacement • Pre-vacuum • Dry heat • Unsaturated chemical vapor

27. Liquid Chemical Sterilant/Disinfectants • Only for heat-sensitive critical and semi-critical devices • Powerful, toxic chemicals raise safety concerns • Heat tolerant or disposable alternatives are available

28. Sterilization Monitoring Types of Indicators • Mechanical • Measure time, temperature, pressure • Chemical • Change in color when physical parameter is reached • Biological (spore tests) • Use biological spores to assess the sterilization process directly

29. Storage of Sterile and Clean Items and Supplies • Use date- or event-related shelf-life practices • Examine wrapped items carefully prior to use • When packaging of sterile items is damaged, re-clean, re-wrap, and re-sterilize • Store clean items in dry, closed, or covered containment

30. Environmental Infection Control

31. Environmental Surfaces • May become contaminated • Not directly involved in infectious disease transmission • Do not require as stringent decontamination procedures

32. Categories of Environmental Surfaces • Clinical contact surfaces • High potential for direct contamination from spray or spatter or by contact with DHCP’s gloved hand • Housekeeping surfaces • Do not come into contact with patients or devices • Limited risk of disease transmission

33. Clinical Contact Surfaces

34. Housekeeping Surfaces

35. General Cleaning Recommendations • Use barrier precautions (e.g., heavy-duty utility gloves, masks, protective eyewear) when cleaning and disinfecting environmental surfaces • Physical removal of microorganisms by cleaning is as important as the disinfection process • Follow manufacturer’s instructions for proper use of EPA-registered hospital disinfectants • Do not use sterilant/high-level disinfectants on environmental surfaces

36. Cleaning Clinical Contact Surfaces • Risk of transmitting infections greater than for housekeeping surfaces • Surface barriers can be used and changed between patients OR • Clean then disinfect using an EPA-registered low- (HIV/HBV claim) to intermediate-level (tuberculocidal claim) hospital disinfectant

37. Cleaning Housekeeping Surfaces • Routinely clean with soap and water or an EPA-registered detergent/hospital disinfectant routinely • Clean mops and cloths and allow to dry thoroughly before re-using • Prepare fresh cleaning and disinfecting solutions daily and per manufacturer recommendations

38. Medical Waste: Not considered infectious, thus can be discarded in regular trash Regulated Medical Waste: Poses a potential risk of infection during handling and disposal Medical Waste

39. Regulated Medical Waste Management • Properly labeled containment to prevent injuries and leakage • Medical wastes are “treated” in accordance with state and local EPA regulations • Processes for regulated waste include autoclaving and incineration

40. Monitoring Options • Water testing laboratory • In-office testing with self-contained kits • Follow recommendations provided by the manufacturer of the dental unit or waterline treatment product for monitoring water quality

41. Definition: Medications that are injected into the body Cases of disease transmission have been reported Handle safely to prevent transmission of infections ParenteralMedications

42. LOW LEVEL DISINFECTANTS • PHENOLIC DISINFECTANTS: • Effective against bacteria (gram+) and enveloped viruses • Not effective against nonenveloped viruses and spores • Active in the presence of organic material • Used for decontamination of hospital environment • Not recommended for semicritical items

43. LOW LEVEL DISINFECTANTS • QUARTERNARY AMMONIUM COMPOUNDS: • Widely used as disinfectants • Contraindicated as antiseptics • Not effective against nonenveloped viruses, fungi and bacterial spores • Commonly used in ordinary environment sanitation of noncritical surfaces

44. INTERMEDIATE LEVEL DISINFECTANTS • ALCOHOLS • Ethyl alcohol • Isopropyl alcohol • Rapidly bactericidal against against vegetative forms of bacteria • Effective against M. tuberculosis, fungi, enveloped viruses

45. INTERMEDIATE LEVEL DISINFECTANTS • ALCOHOLS • Optimum bactericidal concentration is 60-90 % in water • Commonly used topical antiseptics (hand) • Also used to disinfect the surface of medical equipment • May not penetrate organic material • Flammable, irriates tissue, expensive for general use

46. INTERMEDIATE LEVEL DISINFECTANTS • HYPOCHLORITES • Most widely used of the chlorine disinfectants • Most common product is 4-6 % sodium hypochlorite • Inexpensive and fast acting • May produce skin and ocular irritation or gis burns • Corrosive to metals in high concent, inactivated by organic material • Release toxic chlorine gas when mixed with ammonia or acid

47. INTERMEDIATE LEVEL DISINFECTANTS • HYPOCHLORITES • Eliminate enveloped and non envelopedviruses • Effective against fungi, bacteria, algae, but not spores • Broad spectrum of antimicrobial activity • Most recommended for decontamination of hepatitis and HIV viruses • Used as solution in water (20.000 ppm)

48. INTERMEDIATE LEVEL DISINFECTANTS • IODINE AND IODOPHOR • Formulations in soaps (surgical scrubs) • Bactericidal, sporicidal, virucidal, fungicidal • Require a prolonged contact time • Is neutralized in the presence of organic material • Frequent application needed • Irrigate tissues, corrosive • Used for disinfection of some medical equipment (not silicone catheters)

49. HIGH LEVEL DISINFECTANTS • HYDROGEN PEROXIDE • Often used as antiseptic to clean wounds • Greatest effect against anaerobic bacteria • Effective against a broad range of pathogens • Damage tissues in high concentrations • Provides high levelof disinfection in 5 min • May be blended with iodophors, quarterner ammonia, paracetic acid

50. HIGH LEVEL DISINFECTANTS • GLUTERALDEHYDE • Has a wide germicidal spectrum • Used as disinfectant or sterilant • Highly toxic • Only used in a well ventilated setting