HOSPITAL ACQUIRED INFECTIONS Flashcards
what is sterility?
an absolute state of total absence of viable micro-organisms
what is sterilisation?
where products are subjected to a process where all viable micro-organisms are either killed or removed. It is usually the last stage of production
give examples of natural non-specific defence mechanisms
unbroken skin
stomach acid
tears (contain antimicrobial enzyme)
Muco-Ciliary clearance from lungs
what are contaminants?
Bacterial spores Fungal spores fungi gram +/-ve bacteria viruses + prions
what needs to be sterile?
Parenteral products, injections (small volume), infusions (large volume)
Ophthalmic preparations especially if cornea is damaged
Products + devices applied to broken or burn damaged skin
give examples of things that need to be sterilised
Injections, infusions, eye drops+lotions, surgical instruments, dressings, some creams/ointments for burns/large open wounds
what are the 2 examples of a pyrogen test?
rabbit test
LAL test
what is bioburden?
total load of viable micro-organisms present in the product to be sterilised
how much does sterilisation reduce the bioburden by?
bioburden to 10-6 organisms per container
How long will the sterilisation process take?
Can work this out if you know the bioburden and the D-value of an organism resistant to the process
what is the D-value?
(for a thermal process) is the time taken at a fixed temp required to achieve a 90% reduction in the micro-organism population
what are the sources of contamination?
environment
people
how do UK hospitals try to improve hygiene?
Massive effort to educate staff and visitors
Compulsory staff handwashing training
Provision of alcohol gel / liquid
Clear signage / prompts
what are the hospital staffs responsibility to maintain hygiene?
Long fingernails + artificial nails banned
Remove jewellery at start of shift
Maintain good skin condition
must comply with local policies
what is the ‘washing event’?
w
why was the surgical hand disinfectant proposed?
Traditional scrub methods now being re-evaulated
Alcohol handrubs and gels NOT
effective against Clostridium difficle spores
what is ‘bare below the elbows’?
Aims to offer visual re-assurance to patients
may have hygiene benefit
how can you check and measure bioburden on surfaces?
Enzyme luciferase, from fireflies, reacts with an energy storage molecule (ATP) in cells to produce light.
Amount of light produced is proportional to the number of viable cells in the sample.
what is an ATP assay device?
Takes just 30 secs to perform test
Unit can store 100s of readings
what can be used to decontaminate a whole room?
hydrogen peroxide
what is a negative of using hydrogen peroxide to disinfect a room?
All patients + sensitive equipment must be moved out of ward,
hazardous fumes to contain, expensive
what is a positive of using hydrogen peroxide to disinfect a room?
Useful for serious outbreaks / contamination events.
what is now being tested to use to disinfect a whole room?
UV light
