Sterilization, Disinfection, and Antisepsis Flashcards
1
Q
sterilization
A
- describes a process that destroys or eliminates all forms of microbial life and is carried out in health care facilities by physical or chemical methods
- reduces numbers of microorganisms on a device to a level that is insufficient to transmit infectious organisms
2
Q
disinfection
A
- describes a process that eliminates many or all pathogenic microorganisms, except bacterial spores, on inanimate objects
- doesn’t necessarily kill all microorganisms
- reduces numbers of microorganisms on a device to a level that is insufficient to transmit infectious organisms
3
Q
Health care associated infections
A
- over a quarter of all hospital acquired HAIs are caused by four types of infections:
- pneumonia
- bloodstream infection
- urinary tract infection
- surgical site infection
4
Q
high level disinfection
A
- destroys all microorganisms except high number of bacterial spores
- pasteurization and liquid immersion in chemical sterilants (used for heat sensitive semi-critical items such as GI endoscopes, bronchoscopes
5
Q
intermediate level disinfection
A
- destroys vegetative bactera, mycobacteria, most viruses, most fungi, not bacterial spores
- hospital disinfectants with label claim regarding tuberculocidal activity used in non critical patient care items or surfaces with visible blood
- chlorine based products
6
Q
low level disinfection
A
- destroys vegetative bacteria, some fungi and viruses, not sports or mycobacteria
- no tuberculocidal claim-phenolics, quants, 70-90% alcohol
7
Q
antisepsis
A
- the reduction of microorganisms on living skin/tissue
- do not kill spores and can’t be used as disinfectants
8
Q
HAI risk factors
A
- use of indwelling medical devices such as bloodstream, endotracheal, and urinary catheters
- transmission of communicable diseases between patients and HCWs
- surgical procedures
- injections
- contamination of healthcare environment
- overuse or improper use of antibiotics
9
Q
challenges to avoiding HAIs
A
- reprocessing of medical devices is a challenge w
- endoscopes are probably the most challenging reprocessing task in health care
- flexible endoscopes have intricate sophisticated small parts that are difficult to clean before they can be disinfected
- 23.0% of 71 internal channels grew more than 10^6 CFU and 78% of facilities didn’t sterilize forceps
10
Q
Ignaz Semmelweis
A
- professor of obsetrics
- thought particles from cadavers were spreading disease
- said they should soak hands in chlorine (1847)
- people called him crazy
- died in mental institution
11
Q
Florence Nightingal
A
-showed mortality rate in most hospitals was over 50%
12
Q
Joseph Lister
A
- 1865 Pasteur said decay was caused by organisms in air that cause fermentation-lister made connection with wound sepsis
- used carbolic acid to sterilize wounds
- ward remained clear of sepsis for 9 months
- 1869-spray techniques for aseptic surgery
13
Q
decontamination
A
- removal of debris, blood, and proteins and most microorganisms
- not necessarily rendering device safe to handle by HCWs who are not wearing protective attire
14
Q
critical items
A
- instruments or object that are introduced directly into the bloodstream of into other normally sterile areas of the body
- want sterilization
15
Q
semicritical items
A
- non-invasive flexible and rigid fiber optic endoscopes, endotracheal tubes, anesthesia breathing circuits and cytoscopes
- come into contact with mucous membranes or non intact skin, should be free of everything except spores
- high level disinfectant
16
Q
non-critical items
A
- those that either do not ordinarily touch the patient and touch only in tact skin
- have to be careful about MRSA
17
Q
cidal
A
- killing of microoganism
- germicides
- kill microbes but not necessarily their endospores
18
Q
static/stasis
A
-inhibit growth or multiplication of microorganism
19
Q
Resistance
A
- there is a scale of how resistant bacteria and viruses are to various disinfectants
- lipid enveloped viruses most susceptible, prions most resistant
20
Q
conditions influencing the effectiveness of physical and chemical microbial agens
A
- population size
- type of microbe
- physiological state of microbe
- concentration or intensity of antimicrobial agent
- duration of exposure
- temperature
- environmental factors
- amount of organic contamination
- pH
21
Q
physical methods of microbial control
A
- heat-incineration, dry heat, moist heat (below 100-pasteurization, 100=boiling, above 100=autoclave
- radiation-UV, ionizing
- Filtration
22
Q
autoclaving
A
- steam under pressure
- 121 C/15 psi for 15-90 min
- 132 C /27 psi for 4-20 min
- minimal time required
- loading and packing critical to performance
- non toxic to patient staff and enviro
- rapidly microbicidal
- penetrates medical packaging, device lumens
- can’t use for heat sensitive instruments
- microsurgical instruments damaged by repeated exposure
23
Q
flash sterilization
A
- process of sterilizing unwrapped instruments
- uses steam for 3 min at 270 F (132 C) at 27-28 psi
- not routine, only OR
24
Q
pasteurization
A
does not achieve sterility but kills pathogens that might be present in milk, dairy products, beer-mycobacterium, salmonella
- classic-63 C 30 min
- flash-high temp short time (HTST) 72 C 15 sec rapid cooling
- ultra high treatments (UHT) 140 C less than 1 sec, rapid cooling
25
filtration
- excellent way to sterilize solution of heat sensitive materials
- membrane filters of .1 mm thickness-cellulose acetate, cellulose nitrate, polycarbonate, polyvinylidene, difluoride
- pore size .45 or .22 mm for bacteria
- .01 mm for spirochetes, mycoplasma, viruses, and large proteins
26
masks
- physical barrier between your mouth and nose and environment
- N95 are 95% efficient at filtering out particles that are greater than 3 micrometers in diameter
- droplets emitted by sneezing, coughing, talking are 5 micrometers or bigger, so these work well for flu or TB
- must be fit properly every time they are used
27
ionizing radiation
- gamma, x, high E electron beams
- ionization of water forms highly reactive hydroxyl radicals
- uses-pharmaceuticals, disposable dental and medical supplies (syringes, gloves, sutures)
28
nonionizing radiation
- UV-thymine dimers inhibit replication of DNA
- not penetrating
- damages eyes, skin cancer, burns
29
irradiated blood products
- irradiated RBCs help to prevent graft versus host disease
| - prevents proliferation of leukocytes and T cells so the graft can't attack the host
30
irradiated food
- destroys bacteria by damaging DNA
- prolongs shelf life of food in cases where microbial spoilage is the limiting factor
- treatment of hamburger eliminates the residual risk of a contamination by e coli
31
phenol and phenolics
- exert antimicrobial activity by injuring PM, inactivate enzymes and denature proteins
- carbolic acid irritates skin and smell
- used to intermediate and low level disinfection
- triclosan-only good for gingivitis and may be contributing to antibiotic resistance
32
hexachlorophene (pHisoHex)
- most active against gram pos bacteria (staph aureus)
- toxic in newborns
- now used for staph skin decolonization in patients undergoing prosthetic or cardiac valve implant surgery
33
chlohexidine
- not a phenol deriv
- frequently used for disinfection of skin and mucous membranes
- chloraprep
- used for surgical hand scrubs and preop skin prep
- low toxicity, strong affinity to skin or mucous membranes
- killing effect by damaging PM
- effective against most vegetative bacteria but not sporicidal
- can be used in oral rinses
- some people allergic, some conferring resistance
34
aldehydes
- work by forming covalent crosslinks with a number of organic functional groups on proteins
- formalin-37% aq solution of formaldehyde gas
- glutaraldehyde-used to sterilize hospital instruments
- less irritating and more effective that formaldehyde
- Cidex-bacteriocidal,tuberculocida, virucidal in 10 min, sporucidal in 3-10 hours
- only liquid disinfectant that can be considered a sterilant
35
gaseous chemosterilizers
- ethylene oxide, propylene oxide
- denaturation of proteins by alkylation
- sterilize without heat
- sterilization of medical supplies and equipment:disposable plastic syringes, lensed instruments, artificial heart valves, heart lung machine, mattresses
- formaldehyde gas rarely used
- ethylene oxide requires aeration time to remove ETO residue- toxic, carcinogen, flammable
36
formaldehyde gas
- AD-same as formalin, effective penetration
- DISAD-same as formalin, flammable, pot carcinogen, gas irritates
- uses-on site decontamination of biological safety cabinet, HEPA filters
- enclosed areas
37
ETO has
- AD-broad spectrum, no heat/moisture, penetrates packing
- DISAD-flammable, reactive, carcinogen/mutagen, some items may need more than 24 hrs for outgassing
- uses:heat or moisture sensitive supplies, instruments, equipment
38
Quaternary Ammonium Compounds
- Ad-combined detergent and germicidal activity, stable and working dilutions have low toxicity
- Disad-non-sporicidal, limited activity against viruses, mycobacteria, may support growth of bacteria
- uses-surface decontamination, floors, walls, equipment wipe down, antiseptic formulations available
- crestm cepacol
- can be resistant
39
alcohols
- dehydrate cells, disrupt membranes and caus coagulation of protein
- may be used for hard surface disinfection of skin antisepsis
- isopropyl, methyl, and ethyl
- a 70% aqueous solution is more effective at killing microbes than absolute alcohols
- skin disinfectant, surface decontamination, bench top/cabinet wipedown
- inactivates most viruses with lipid envelope
- can't penetrate protein rich materials
- flammable
40
handwashing and sanitizer
- less time, more effective unless hands are visibly soiled
- reduces bacterial counts on hands
- more accessible than sinks
- physicians more willing than washing hands
41
halogens-iodine and chlorine
- oxidizing agents and cause damage by oxidation of essential sulfydryl groups of enzymes
- chlorine reacts with water to form hypochlorous acid, which is microbicidal
- chlorine gas is used to bleach water
- household bleach can be used at a dilution of 1:10 in decontamination of spillage of infectious material
- disadvantage-unstable when diluted-needs to be made daily, don't work on organic matter as well, may be corrosive
42
iodine preparations
- tincture of iodine (2% iodine, 70% alcohol) is an antiseptic
- iodophores-iodine can be combined with neutral carriers such as polyvinylpyrrolidone to prepare iodophores such as povidone-iodine
- betadine,isodine
- iodophores permit slow release and reduce irritation of antiseptic
43
heavy metals and organic acids
- metals combine with SH groups on proteins
- heavy metals-silver nitrate (1% for ohpthalmic prep), mercurochrome, copper sulfate, zinc chloride/oxide
- organic acid deriv-sorbic acid, benzoic acid, methylparaben, propylparaben
44
h2o2
- acts on the microorganisms through its release od nascent oxygen, produces hydroxyl free radicals that damages proteins and DNA
- used at 6% concentration to decontaminate instruments and equipment such as ventilators
- 3% used for skin disinfection and cleaning of wounds and ulcers
- strong solutions are sporicidal
- decomposes in light, broken down by catalase, proteinaceous organic matter drastically reduces activity
45
Peracetic Acid
- mixture of acetic acid and h2o2 in aq soln
- PAA disinfects by oxidizing the outer cell membrane of vegetative bacterial cells, endospores, yeast, and mold spores
- cooling tower water disinfectant where it prevents biofilm/legionella
- effective for sanitizing fowl carcasses without affecting skin or flesh-applied to meat
- plasma (gas phase) sterilization
46
plasma sterilization
- beneficial for sterilizing temperature sensitive polymeric material (endoscopes)
- safe, non tixic dry, low temp sterilization in 1 hour
- generated in an enclosed chamber under deep vacuum using UV or microwaves to create free radicals in a gaseous phase
- free radicals kill bacteria
47
STERRAD
- uses low temp h2o2 gas plasma tech to sterilize instruments and medical devices
- quick reprocessing
- express cycle for da Vinvci 3D endoscopes and other devices without lumens
- processes a wide range of instruments including multiple single channel flexible endoscopes, cameras, rigid scopes, light cords, batteries, power drills
