Disinfection Flashcards
What is the difference between biosecurity & infection control
Biosecurity: Preventing infection from entering site, managing animal & material movement into hospitals, farms & clinics.
Infection Control: Reducing risk of infection within site through processes like cleaning & reducing reinfection risk
What are the 4 levels of cleaning
Physical cleaning: Removal of material contamination.
Sanitation: Application of chemical reduce contamination
Disinfection: Use of licenced product to kill pathogens (virus, bacteria & parasites) variable efficacy on spores.
Sterilisation: Validated inactivation of pathogens including spores.
What are the goals of disinfection in infection control?
Reduce infection & reinfection
Prevent spread on surfaces & fomites
Manage infected materials effectively
*Perform thorough cleaning before disinfection
What is the relative resistance of pathogens to disinfection (from most resistant to least)?
why are mycobacteria resistant to disinfection
have mycolic acids in the membranes which make then less susceptible to chemical penetration so more tolerant.
why are spores resistant to disinfection
have evolved to tolerate hostile environments and are inert.
why are TSEs resistant to disinfection
very tolerant as already denatured so need compounds that degrade such as strong hypochlorite for a long time, often damaging the thing you try to disinfect so where TSEs suspected equipment may end up being treated and disposed of.)
What considerations are there for the use of disinfectants?
Generalised action
Damaging
Potential harm to self/patient
Some toxic so tainting a risk
Hypersensitivity
What are some common disinfectants & their mechanism?
Alcohols: Denature proteins, damage lipids (fast-acting but flammable).
Alkalis: Alter pH & saponify fats (effective but caustic).
Aldehydes: Denature proteins & alkylate nucleic acids (toxic, carcinogenic).
Oxidizing agents: Denature proteins (environmentally friendly, corrosive).
Phenols: Disrupt cell walls & denature proteins (stable but toxic to certain species).
Halogens (Chlorine/Iodine): Denature proteins, effective on broad spectrum (corrosive, UV-sensitive).
What are the components of infection control plans?
What can be done to prevent spread of infection via the faecal-oral route in practice?
Thorough cleaning guidelines for all animal contact items & surfaces
Food rotated first in first out basis (i.e. not constantly topped up)
Food stored where pest can’t get in (i.e. rodents on farms)
Waste & Food streams kept separate
Isolation units for patients with suspected/diagnosed infectious disease
Routine to clean areas of exercise /general areas
Prompt cleaning of bodily fluids where patient traffic may occur
Give examples of how contacts can be controlled in an infectious case
Limit staff-patient interactions
Reduce congestion in waiting areas
Cover wounds or draining tracks
Use disposable items where possible
Sequence patient rounds (clean to infectious areas last)
Cleaning protocols for stalls, pens, carriers
Barrier control
Give examples of intervention strategies for fomites
Wash hands frequently or use gloves
Clean & disinfect equipment after each use
Avoid topping off dispensers; use full refills
Disinfect shoes & boots regularly & use dedicated work footwear
Hand free sinks & towel dispensers
Change PPE when dirty
Give examples of intervention strategies for farm facilities
Never use manure buckets to move feed
Pest control, insect repellents
House different ages groups separately
Minimise manure run-off/have adequate storage
Drain areas with standing water
Advise clients to isolate incoming animals / returning patients
Have foot bath/protective clothing available for visitors (spray down vehicles)
Have a routine protocol for biosecurity
Put in step-over barriers
What are specific strategies for controlling Streptococcus equi?
Quarantine & screen new arrivals
Disinfect fomites & educate handlers
Use hypochlorite or QAC disinfectants with proper contact time
Rest contaminated pastures for several weeks
Consider route of infection, close contact & aerosols
What are the control strategies for managing Salmonella on an equine site?
Isolate positive cases
minimize area traffic
Clean thoroughly before disinfection
Use protective clothing and separate equipment
Manage waste appropriately
Sequence rounds contacting isolated animals last
How can canine Parvovirus be managed?
Use barrier controls & proper PPE
Disinfect with hypochlorite (bleach) for at least 1-hour contact time
Focus on vaccination and pre-admission biosecurity
