Infection control in the dental setting Dr Kate Miller College of - PDF document

27/03/2020 Infection control in the dental setting Dr Kate Miller College of Public Health, Medical and Veterinary Science James Cook University McGregor Rd. Smithfield 4878 kate.miller1@jcu.edu.au Learning Objectives At the end of this lecture students should be able to: 1. Discuss basic principles of effective control of microbial growth 2. List the main methods used to destroy and inactivate microorganisms 3. Explain why infection control is important in healthcare settings Why is infection control important? • Both patients and dental health care personnel (DHCP) can be exposed to pathogens • Eg. blood-borne viruses (BBV), respiratory tract viruses • http://www.abc.net.au/news/2015-07-02/dental- health-hiv-hepatitis-scare-sydney-may-affect- thousands/6588534 • Proper procedures can prevent transmission of infections among patients and DHCP • Treat all patients as potential carriers • Have effective cleaning, disinfection and sterilisation procedures • Need to “break” the chain of infection 1

27/03/2020 Potential sources of infection from patients and staff SOURCES OF INFECTION Patients in the acute phase of an infection EASILY RECOGNISED Influenza, common cold Patients in the prodromalphase of an NOT EASILY RECOGNISED infection Measles, mumps, chickenpox Healthy carriers of pathogenic organisms NOT EASILY RECOGNISED Includes convalescent carriers and asymptomatic carriers HIV, hepatitis B and C, herpes viruses Bagg, et al. Figure 30.3 Typhoid Mary • Lived from 1869-1938 Known carrier of typhoid bacteria ( Salmonella typhi ) • First identified asymptomatic carrier • Shed bacteria in faeces and urine (no symptoms) • Worked as a cook moving around the New York city region. • Worked for 8 families, members of 7 fell ill with typhoid fever. • Infected at least 53 people with 3 deaths (underestimate) • Disease: severe diarrhoea and fevers • Spread by faecal-oral route. Need vigorous scrubbing with soap and hot water to remove the bacteria from the hands • Suspected as a carrier by medical profession • Typhoid Mary is a generic term for a healthy carrier of a dangerous disease. Modes of transmission • Direct • Unprotected contact with infectious lesions or other skin infections • Herpes, gonorrhea, ringworm • Droplet • Coughing and sneezing (<1 metre) • Colds, influenza, TB, whooping cough, SARS, chicken pox, measles, mumps • Exchange of bodily fluids • HIV, hepatitis, cytomegalovirus, EBV 2

27/03/2020 Modes of transmission • Indirect • Airborne • Pathogens carried >1 metre • Dental aerosols, Air conditioning units • Spore-forming bacteria, fungal spores, oocysts/cysts (can tolerate drying out), Legionnaires disease • Contaminated objects (fomites) • Microbes are transferred to an object or surface (fomite) then to a susceptible host • Medical instruments, clothing, taps, door handles, telephones, computer keyboards • Microbes transmitted on fomites include Vancomycin-resistant Enterococcus, methicillin-resistant Staph. aureus, Strep. pyogenes, Pseudomonas aeruginosa, rhinoviruses, rotavirus, Candida, Athlete’s foot Potential routes of transmission in the dental surgery • Contaminated saliva or blood • Contaminated instruments and surfaces • Inhalation of airborne pathogens • Aerosols • Improper sterilisation If Saliva were Red https://www.youtube.com/watch?v=hLHMEF6RAtY Saliva contains up to 10 8 microorganisms per ml Bagg, et al. Figure 30.1 Key elements of infection control • Medical history • Dental instrument decontamination (for reusable devices) • Disinfection of laboratory items • Use of disposables • Decontamination of surgery surfaces • Personal protective equipment • Avoidance of needlestick and other sharps injuries • Immunisation of staff • Effective ventilation • Safe waste disposal • Effective training of staff • Effective management of infection control • Audit Bagg, et al. Figure 30.4 3

27/03/2020 Standard precautions in healthcare settings • Standard Precautions (sometimes called Universal Precautions) = all patients/samples treated as potential carriers/hazards • Standard precautions are applied at all times • We need them because: • people may be placed at risk of infection from others who carry infectious agents; • people may be infectious before signs or symptoms of disease are recognised or detected, or before lab tests are confirmed in time to contribute to care; • people may be at risk from infectious agents present in the surrounding environment including environmental surfaces or from equipment; and • there may be an increased risk of transmission associated with specific procedures and practices. Standard precautions consist of : • hand hygiene, before and after every episode of patient contact ; • the use of personal protective equipment ; • the safe use and disposal of sharps ; • routine environmental cleaning ; • reprocessing of reusable medical equipment and instruments ; • respiratory hygiene and cough etiquette; • aseptic non-touch technique; • waste management Dental instrument decontamination • Legislation covering the cleaning, disinfection and sterilisation of reusable medical devices (AS/NZS4187-2003) • Surgical instruments must be sterile at point of use • Procedures used during the reprocessing of contaminated instruments must minimise risk of exposure of dental staff 4

27/03/2020 Important terms used in destruction or control of microorganisms • Antiseptic - Type of chemical disinfectant suitable for use of skin or living tissue, used to kill or remove harmful microorganisms without damaging the tissues • Biocide - Chemical capable of killing microbe • Decontamination - Removal of possibly harmful microorganisms from an object by cleaning or disinfecting • Cleaning - Mechanical removal (+ usually detergent and water) of material from surface of an object Important terms used in destruction or control of microorganisms • Disinfectant - Type of chemical suitable for use on inanimate objects • Disinfection - destruction or removal of most microorganisms (usually kills bacteria, may not kill spores and viruses) • Sterilisation - complete destruction or removal of all microorganisms including spores and viruses • Sterile - free of all living organisms Approaches to prevent infection in healthcare settings • Removal of microorganisms from the environment • Cleaning • Disinfection • Removal of organisms from patient care equipment • Often requires cleaning, disinfection or sterilisation (sometimes all three) • Depends on equipment type 5

27/03/2020 Instruments and infection risk 1. Critical instruments Penetrate mucous membranes or contact bone, the bloodstream, or other normally sterile tissues (of the mouth) - Surgical instruments, scalpel blades, periodontal scalers 2. Semi-critical instruments Contact mucous membranes but do not penetrate soft tissue - Dental mouth mirrors, amalgam condensers, and dental handpieces 3. Non-critical instruments Contact intact skin - X-ray heads, bib chain, alginate spatula, protective eyewear Processing in JCU Dental JCU Dental manual p.45 Cleaning • Sites that may harbour microorganisms • Blood • Pus • Mucous • Grease • Dirt • Microorganisms require organic compounds and water to reproduce • Detergent is a solvent • Instrument and equipment cleaning • Environment cleaning 6

27/03/2020 Cleaning • Instrument and equipment • Physical removal of debris • Manual scrubbing and/or ultrasonic bath, or automated washer • Detergent, disinfectant/detergent or enzymatic cleaner • Environment • Transmission through indirect contact • Routine cleaning of floors, walls, furnishings important • Details in Australian Guidelines for the Prevention and Control of Infection in Healthcare Disinfection • Disinfection = Removal or destruction of harmful microbes not usually including bacterial spores • Does not sterilize • Methods • Heat • Pasteurisation, controlled temp washers, boiling for 5 min • Radiation • Short wave UV • Liquids • Phenolic compounds, bleach, 70% alcohol, glutaraldehyde Factors affecting liquid disinfectant activity • Properties of organisms • bacterial spores are highly resistant, Gram-negative more resistant than Gram-positive, non-enveloped viruses more resistant than enveloped • Inactivation • presence of soil (blood, pus) or incompatibility with other chemicals • Dilution/volume • Use manufacturer’s instructions for concentration and contact time • Contact time • a prolonged contact time may be required for sporicidal activity 7