Week 6 - Infection Control in Healthcare settings UPDATED Flashcards
Define infection control
processes and precautions taken to control the spread of infection
What is the chain of infection
the cycle of which infection is continuously spread
1. infectious agent
2. Reservoir (water, food, soil, humans, animals)
3. Portal of exit
4. made of transmission (droplet, faecal-oral, vector-borne)
5. portal of entry (mouth, nose, skin cuts, eyes)
6. susceptible host (human)
What are the basic principles of effective control of microbial growth
- Physical Strategies
- Immunization
- Chemotherapeutic
what does it mean by physical strategies
sterilization and disinfection
What does it mean by immunization
Use of antigens from a specific microbe to generate a protective immune response
What does it mean by Chemotherapeutic
Use of drugs to kill or inhibit growth of microorganisms
What are the standard precautions in healthcare settings
Treat all patients as potentially infectious because of prodromal phase, asymptomatic carriers and transmission risk associated with certain procedures.
- hand hygiene
- use of PPE
- safe use and disposal of sharps
- routine environmental cleaning
What are the main methods used to destroy and inactivate microorganisms in heathcare settings
- Removal of microorganisms from the environment through - cleaning and disinfection
- Removal of organisms from patient care equipment through - cleaning, disinfection and/or sterilization
What sites need to be cleaned
- blood
- pus
- mucous
- grease
- dirt
What are methods which clean equipment
- automated washer
- ultrasonic bath
- manual
Methods of disinfection
- heat - boiling for 5 min
- liquids e.g. phenolic compounds, bleach, 70% alcohol
What makes bacteria harder to be disinfected
if the bacteria has
- spores (tough outer layer)
- gram negative (LPS acts as a protective barrier)
- non-enveloped (disinfectants target the lipid envelope)
- a large amount of bacteria
- contact time
- repeated exposure as it gains resistance
What are types of antiseptics
- alcohol e.g. skin wipes
- chlorhexidine (common)
- iodine-containing
What are the different levels of risk for care equipment
Critical
Semi-critical
Non-critical
What makes a piece of equipment classified as critical
If they penetrate sterile tissue, body cavity or bloodstream
How do you clean critical level equipment
Sterilisation
What are examples of critical risk equipment
surgical instruments, needles, periodontal scalers, implants
What is a semi critical level of risk item
an item which comes in contact with mucous membranes or non intact skin
How do you clean semi critical level risk items
single use
sterilization
high level chemical disinfection
Examples of semi critical level risk items
dental mouth mirrors
amalgam condensers
dental handpieces
What are non-critical level of risk items
items which only come in contact with intact skin
How do you clean non critical level risk items
cleaning
decontamination
Examples of non critical level risk items
x ray heads
bib chain
alginate spatula
protective eyewear
How is equipment in JCU cleaned
sterilisation
JCU - item is washed in the thermal instrument washer, is wrapped, tracked then sterilised
e.g. surgical instruments, needles, periodontal scalers, implants
How does Sterilization work
Using an autoclave
Autoclaves steam the tools under pressure and high temperature. The combination of high temperature (usually around 121°C) and pressure (typically 15 psi or higher) effectively kills microorganisms, including bacteria, viruses, and fungi, as well as their spores.
What impacts steriliaztion
- high amounts of micro-organisms
- presence of organic material to buffer the effect of the sterilant
What are alternative methods to sterilization
- Filtration (heat sensitive instruments)
- Hydrogen peroxide (delicate instruments)
- Incineration (disposable equipment)
- Gamma irradiation (anesthetics, syringes, implants, single-use medical supplies)
How do you store sterile and clean items
- 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
Why is infection control important in healthcare settings
- infections can be transmitted in medical settings and procedures
- to break chain of infection - to prevent the spread of infectious diseases into and out of people - to prevent the pathogenic outcomes of the illness
- Protect vulnerable patients
- Maintenance of patient safety
How can patients and dental health care professionals be infected within healthcare settings
- sharp instruments
- aerosol (mode of infection transmission)
- saliva and plaque
- other patients (acute phase, prodromal phase, healthy carriers)
What are the modes of trasmission
- Direct
- Indirect
What is the direct mode of transmission
- unprotected contact with infectious lesions or other skin infections e.g. Herpes, gonorrhea
- droplet (aerosols which turn into droplets in less than 1 m) e.g. coughing and sneezing
- Exchange of bloody fluids e.g. HIV, hepatitis
What are the forms of indirect modes of transmission
- Airborne (droplets which can travel as an aerosol for more than 1m) e.g. dental aerosols
- Contaminated objects (formites) - medical instruments, clothing, surfaces
How is HIV spread
Infected instrument or direct injection of blood
How is Hepatitis B spread
Sharps injury
How is Hepatitis C spread
Re-using needles, poor infection control practices
Define antiseptic
- Use for people
- type of chemical disinfectant suitable for use of skin or living tissue, used to kill or remove harmful microorganisms without damaging the tissue
Define disinfectant
- not used on people
- type of chemical suitable for use on inanimate objects
Define disinfection
destruction or removal of most microorganisms (usually kills bacteria, may not kill spores and viruses)
Define sterilization
Complete destruction or removal of all microorganisms including spores and viruses
Define sterile
free of all living organisms
define decontamination
removal of possibly harmful microorganisms from an object by cleaning or disinfecting
define cleaning
mechanical removal (+usually detergent and water) of material from surface of an object
Define biocide
chemical capable of killing microbe
What is the minimum volume of blood to transmit HBV
0.04 uL
What is the minimum volume of blood to transmit HCV
0.6 - 0.8 microL
What is the minimum volume of blood to transmit HIV
100 microL
What is the percentage risk of infection following needlestick injury from a seropositive patient of HBV
7-30%
What is the percentage risk of infection following needlestick injury from a seropositive patient of HCV
1.8%
What is the percentage risk of infection following needlestick injury from a seropositive patient of HIV
0.3%
What is an acute phase of infection and how recognizable is it
short-term illnesses that can be severe but come and go quickly
e.g. influenza, common cold
EASILY RECOGNISED
What is an prodromal phase of an infection and how recognizable is it
not easily recognized
The stage after incubation and before symptoms occur
Measles, mumps, chickenpox
What was the significance of Typhoid Mary
First asymptomatic carrier of Salmonella typhi
