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Welcome to Section E, Principles of Disinfection and Sterilization in the

Out-Patient Practice Settings. This is the fifth of a seven part state

approved course required to meet compliance with the NC Rule .0206

Infection Control in Healthcare Settings. This course is specifically

designed for the Out-Patient practice Settings.

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Every year millions of invasive medical procedures are performed in the

outpatient settings. Each of these procedures involves contact by a

medical device or surgical instrument with a patient’s sterile tissue or

mucous membranes. A major risk of all such procedures is the

introduction of pathogens which can lead to infection. Failure of

appropriate disinfection and sterilization can also lead to person to

person trans mission of BBP or MTb.

The objectives of this lecture are to have the participants be able to

state the principles of cleaning, disinfection and sterilization; and be

able to list the current methods for disinfection and sterilization, per the

CDC HICPAC Guideline for Disinfection and Sterilization in Healthcare

Facilities published in 2008. These Guidelines should be used for

developing policies and procedures in all healthcare practice settings.

It is critical that the facility designated infection preventionist be familiar

with the concepts of cleaning, disinfection, and sterilization to ensure

appropriate methods, monitor and evaluate practice, and monitor

patient outcomes in order to identify failures in practice or processes.

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Over 35 years ago, Dr Earle Spaulding devised a rational approach to

disinfection and sterilization of patient care items based on the item’s

intended use. He placed every patient care item into one of three

categories based on the risk of infection involved with its use. The 3

categories are critical, semi-critical, and noncritical. The level of

disinfection or sterilization then is dependent on the category the item is

placed in: critical are items that contact sterile tissue such as surgical

instruments and must be sterilized; semi-critical are items that contact

mucous membranes such as endoscopes or non-intact skin such as

wound therapy equipment and must be high-level disinfected because it

kills all but high numbers of bacterial spores; and noncritical devices

that contact only intact skin such as stethoscopes which must be low-

level disinfected.

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To understand why certain disinfection or sterilization products and

process are recommended, one must understand that microorganisms

have differing abilities or characteristics for resistance to disinfectants

and sterilants. In terms of most to least resistant, Prions, the causative

agent of Mad Cow and CJD disease, are the most resistant and do not

respond to conventional chemical and physical decontamination

methods. Next, in terms of resistance, are spores of which Clostridium

difficile, or C diff is common, and has a protective covering that forms in

about a day after it is expelled in fecal material into the environment.

Then MTB which also has a protective outer covering and makes it

more difficult to kill. The non-enveloped viruses which include norovirus

are resistant to alcohol and this is problematic because of the lack of

effectiveness associated with the widely used alcohol-based hand rubs

in healthcare. Next are the fungi like Candida, followed by the common

vegetative bacteria like Staph, strep, enterococci, and the gram

negatives like pseudomonas, E coli, Serratia. Finally, the easiest to kill

are the enveloped viruses like HIV and HBV.

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Healthcare workers (HCWs) should be aware that there are factors that

are known to influence the efficacy of the disinfection and sterilization

process outcome to include: one of the most important is the cleaning of

the object. Cleaning reduces the bioburden and removes foreign

material (organic and inorganic salts) that interfere with sterilization

process by acting as barriers to the sterilization agent. Precleaning in

patient-care areas may be needed on items that are heavily soiled with

feces, sputum, blood, and so on. Items sent to Central Processing

without removing gross soil may be difficult to clean because of dried

secretions and excretions. One of the common failures of reprocessing

is not testing to confirm that the concentration and exposure time to the

disinfectant or sterilant follows the manufacturer’s directions. Another

factor is the nature of the object, meaning does the object have hinges,

crevices, or lumens that could create difficulties in reprocessing. Some

factors that influence disinfectant processes are temperature and water

hardness. For example the activity of disinfectants increases as the

temperature increases, but some exceptions exist. Furthermore, too

great an increase in temperature causes the disinfectant to degrade

and weakens its germicidal activity. An increase in pH improves the

effectiveness of some disinfectants (glutaraldehydes, quaternary

ammonium compounds) but decreases the antimicrobial activity by

altering the disinfectant molecule of phenolics, hypochlorites, and

iodine. Also, water hardness reduces the rate of kill of certain

disinfectants.

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The first of the three categories we will review is the processing of

critical instruments and patient care items.

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Critical patient care items or instruments involve a high risk of infection.

These items penetrate the bloodstream or other normally sterile tissues.

They have the highest risk of transmitting infection and should be heat-

sterilized between patient uses. Alternatively, use sterile, single-use

disposable devices.

The goal of sterilization processing is to kill all microorganisms.

• Examples of items included in this category are surgical

instruments, for example scalpels, cardiac catheters, all

intravenous devices, and urinary catheters,

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The next category is semi-critical instrument processing. Semi-critical

items and equipment are very commonly used in the out-patient setting.

One of the most commonly used items in this category is endoscopes

used for millions of procedures in the US each year for diagnostic

screening, treatment, and surgery. However, more healthcare

associated outbreaks have been linked to contaminated endoscopes

than to any other medical device. This is because of the complexity of

the equipment, with multiple channels and difficulty of adequately

reprocessing. Endoscopes have been associated with numerous

breeches including: inadequate cleaning, improper selection of cleaning

and disinfecting agents, failure to follow automatic endoscopic

reprocessor (AER) manufacturer’s recommendations for disinfection, or

lack of maintenance resulting in healthcare associated infections and

outbreaks.

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Semi-critical items are those items that contact only mucous

membranes or non-intact skin and do not penetrate soft tissues. Intact

mucous membranes, such as those in the lungs or the GI tract,

generally are resistant to infection by common bacterial spores, but

susceptible to other organisms, such as bacteria, mycobacteria, and

viruses. As such, they have a lower risk of transmission than critical

items.

Semi-critical instruments require high level disinfection to kill all

microorganisms except high numbers of bacterial spores.

Items in this category that are heat-tolerant should be heat sterilized

between patient uses. For respiratory therapy equipment that is heat

sensitive, facilities may use the heat automated pasteurization method.

However, for other heat-sensitive instruments immersion in chemical

sterilants will achieve high level disinfection (HLD).

Examples of semi-critical instruments include respiratory therapy

anesthesia and equipment, GI endoscopes and bronchoscopes, ear and

vaginal speculums, and diaphragm fitting rings.

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There are many products on the market that can be used for high level

disinfection of semi-critical items. Healthcare providers should follow the

manufacturers’ directions for use of products to achieve high level

disinfection. The times for immersion to achieve high level disinfection

will vary according to the germicide used and the concentration. The

exposure times may be as short as 10 minutes or as long as 45

minutes, and at in-use temperatures from 20o to 25oC.

Glutaraldehyde, hydrogen peroxide, ortho-phthalaldehyde, peracetic

acid with hydrogen peroxide and chorine are cleared by the Food and

Drug Administration (FDA) provided all factors recommended are met.

Compatibility of some sterilants with patient equipment should be

considered when choosing products for high level disinfection; for

example some scopes may be damaged when using hydrogen peroxide

formulations. Importantly, outbreaks continue to occur particularly in the

outpatient settings when ineffective disinfectants, including iodophors,

alcohol, and over-diluted glutaraldehyde are used for high level

disinfection.

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The last category is noncritical items. In contrast to critical and some

semi-critical items, most noncritical items may be decontaminated

where they are used and do not need to be transported to a central

processing area. There is no direct risk of infection from patient contact

with contaminated noncritical items used on patients’ intact skin.

However, there is a risk of a subsequent secondary infections to

patients from contact with contaminated noncritical items used during

patient care. This can happen by secondary transmission, when HCWs

handle contaminated noncritical items (blood pressure cuffs) without

performing adequate hand hygiene or are wearing gloves that are not

changed. Or, the patients themselves touching contaminated surfaces

in their environment ( bedrails, exam tables) colonize their skin or

mucous membranes with MDROs that could become a subsequent

secondary infection with that pathogen, especially if the patient has

areas of non-intact skin, invasive procedures or devices, or have

underlying immunocompromising conditions.

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There are non-critical surfaces like the walls, floors, windows, room

curtains. And then there are noncritical devices and instruments that are

directly on the patient. Noncritical instruments and devices only contact

intact (unbroken) skin, which serves as an effective barrier to

microorganisms. However, these devices, if contaminated with

epidemiological important organisms (MDROs), could result in

colonization of the patient or HCWs hands.

These items carry a lower risk of transmitting infections and usually

require only cleaning and low-level disinfection.

Intermediate-level disinfectants destroy vegetative bacteria,

mycobacteria, most viruses, most fungi, but not bacterial spores. Low-

level disinfectants destroy vegetative bacteria, some fungi and viruses,

but not mycobacteria or spores.

When using a low-level disinfectant and there is visible blood on the

item, according to OSHA it must have a label claim for killing HIV and

HBV or have tuberculocidal activity. Alternatively, if an item is visibly

bloody, it may be cleaned and disinfected using an intermediate-level

disinfectant before use on another patient.

• Examples of instruments in this category include blood

pressure cuffs, EKG leads, pulse oximeters, stethoscopes, and

bedpan.

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Intermediate-level EPA-registered hospital disinfectants are those with label claims regarding tuberculocidal activity such as chlorine-based products with a 1:10 or 1:100 dilution, phenolics, and some quaternary ammonium compounds. Low-level EPA- registered hospital disinfectants with no tuberculocidal claim may include chlorine at a 1:500 dilution,( or 100 ppm concentration), quaternary ammonium compounds, or 70 to 90% alcohol.

A relatively new product available is accelerated hydrogen peroxide which contains very low levels of anionic and nonionic surfactants that act with hydrogen peroxide to produce microbicidal activity. These ingredients are considered safe for humans and benign for the environment. This product is prepared and marketed in several concentrations from 0.5% to 7%. The lower concentrations (0.5%) are designed for the disinfection of hard surfaces while the higher concentrations (2%) are recommended for use as high-level disinfectants. A 0.5% accelerated hydrogen peroxide demonstrated bactericidal and virucidal activity in 1 minute, and mycobactericidal and fungicidal activity in 5 minutes. It is more costly than other low-level disinfectants such as quaternary ammonium compounds. The product is claimed to have an excellent antimicrobial performance and a favorable safety profile.

Generally, HCWs should follow the manufacturer's ―use dilution‖ for all products to achieve the level of disinfection required. Exposure times vary but are minimally 60 seconds to allow for drying and completion of the disinfectant activity.

One major controversy of disinfecting non-critical surfaces is that the CDC Disinfection and Sterilization Guidelines recommended a minute exposure for all non-critical surface disinfection, which is in conflict with manufacturer’s instructions. In order to get EPA clearance of the CDC Guideline, it was necessary to insert the sentences, "By law, all applicable label instructions on EPA-registered products must be followed. If the user selects exposure conditions that differ from those on the EPA-registered product label, the user assumes liability from any injuries resulting from off-label use and is potentially subject to enforcement action under FIFRA". There are several points that should be made about this apparent disconnect between label instructions and what studies show. Multiple scientific studies have demonstrated the efficacy of hospital disinfectants against pathogens causing healthcare-associated infections with a contact time of at least 1 minute; the only way an institution can achieve a contact time of 10 minutes is to reapply the surface disinfectant 5-6 times to the surface as the typical dry time for a water-based disinfectant is 1.5-2 minutes and currently, healthcare facilities like UNC Health Care are achieving surface disinfection of non-critical patient care items and environmental surfaces by one application of a disinfectant and requiring a >1 minute dry time; equally important as disinfectant contact time is the application of the disinfectant to the surface or equipment to ensure that all contaminated surfaces and non-critical patient care equipment are wiped as current studies demonstrate that only approximately 50% of high-risk objects are cleaned at terminal cleaning. There are no data that demonstrate improved infection prevention by a 10 minute contact time versus a 1 minute contact time. Thus, the CDC Disinfection and Sterilization Guideline authors, who are from UNC Healthcare, believe the guideline allows them to continue the use of low-level disinfectants for noncritical environmental surfaces and patient care equipment with a 1 minute contact time Additionally, all healthcare facilities should emphasize the thoroughness of cleaning to ensure that all contaminated surfaces are wiped.

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Many Ambulatory Care facilities are challenged with space limitations

for complying with CDC recommendations when reprocessing reusable

patient care items. In the next section, we will review the steps for

instrument processing. The Central Processing area ideally should be

divided into at least 3 separate areas. Physical barriers should

separate the decontamination area from the other sections to contain

contamination on used items. In the decontamination area reusable

contaminated supplies are received, sorted, and decontaminated. The

recommended airflow pattern should contain contaminates within the

decontamination area and minimize the flow of contaminates to clean

areas. The American Institute of Architects recommends negative

pressure and no fewer than 6 air exchanges per hour in the

decontamination area; AAMI recommends 10 air exchanges per hour in

the decontamination room and positive pressure in the sterilizer

equipment room. The packing area is for inspecting, assembling, and

packaging clean but not sterile items. The sterile storage area should be

a limited access area except for sterile storage, where the relative

humidity should not exceed 70%. The walls, floors, and ceiling should

be made of non-shedding materials.

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Most instrument cleaning, disinfecting, and sterilization should occur in a

designated central processing area to control both quality and personnel

safety.

To prevent cross-contamination, the instrument processing area should

be physically or spatially divided into 3 regions for cleaning, packaging,

sterilization, and storage.

• In the cleaning area, reusable contaminated instruments are

received, sorted, and cleaned.

• The packaging area is for inspecting, assembling, and

packaging clean instruments in preparation for final sterilization.

• The sterilization and storage area contains the sterilizers and

related supplies, incubators for analyzing spore tests (if

performed in office—although some states require using a

testing service), and can contain enclosed storage for sterile

items and disposable (single-use) items.

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Cleaning is the first step in all decontamination processes. Cleaning

involves the physical removal of debris by scrubbing and using water

with detergents or enzymatic cleaners, or by an energy based process

such as using washer-decontaminators or ultrasonic cleaners.

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Automated or mechanical cleaning equipment, such as ultrasonic

cleaners, instrument washers, and washer-disinfectors, are commonly

used to clean instruments. Automated cleaners improve the efficacy of

the cleaning process and reduce the handling of sharp instruments. A

more alkaline detergent is generally used with mechanical equipment to

compensate for the lack of friction used with manual cleaning. The

manufacturer’s recommendations for dilution, temperature, water

hardness, and use (designed for use in washer/decontaminators) should

be followed. After cleaning, instruments should be rinsed with water to

remove chemical or detergent residue.

Photo credit: Chris Miller, PhD, Indiana University School of Dentistry.

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If manual cleaning is necessary, soak instruments in a rigid container filled with a

detergent/disinfectant, enzymatic cleaner, or even plain water. This step prevents

drying of patient material and makes cleaning easier and less time consuming. Manual

cleaning requires a nearly neutral detergent. Enzymes, usually proteases are

sometimes added to neutral pH detergent solutions to assist in removal of organic

material. Cleaning solutions can also contain lipases (enzymes active on fats) and

amylases (enzymes active on starches). Enzyme detergents are cleaners, not

disinfectants, and some disinfectants may inactivate enzymes. Neutral pH detergents

that are compatible with medical instruments and endoscopes may be the best choice

for cleaning, especially delicate instruments. Some data show that enzymatic

detergents are more effective than neutral pH detergents. New formulations of non

enzymatic hydrogen peroxide have demonstrated efficacy comparable to enzymatic

detergents in removing protein and endotoxin materials in lab testing.

Other issues include:

• Do not use high-level disinfectants/sterilants (e.g., glutaraldehyde) as

instrument-holding solutions.

To avoid injury from sharp instruments, personnel should wear puncture-resistant,

heavy-duty, utility gloves (i.e., not patient care gloves,) proceed slowly and carefully

when handling or manually cleaning contaminated instruments and devices to avoid a

percutaneous injury.

Submerge instruments in detergent solution and scrub with long handled brush to

avoid spattering

• To protect against splashes, a facemask, eye protection or face shield, and a

gown or jacket should be worn.

Photo credit: Lt. Col. Jennifer Harte, U.S.A.F. Dental Investigation Service, Great

Lakes, IL.

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After thorough cleaning and drying of instruments, critical and semi-

critical instruments that will be stored before use should be wrapped or

placed into container systems prior to heat sterilization. This step

protects items from contamination after the sterilization cycle and during

storage.

Open or unlock hinged instruments so that all surfaces are exposed.

Place a chemical indicator inside each wrapped package. If the

indicator cannot be seen from the outside, place another indicator (e.g.,

indicator tape) on the outside of the package.

Always wear heavy-duty, puncture-resistant utility gloves while

inspecting and packaging instruments.

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After items are packaged, they are ready to undergo the sterilization

process, the goal of which is the complete elimination or destruction of

all forms of microbial life by either physical or chemical processes.

21

There are two types of heat sterilization methods commonly used in

outpatient settings.

1) Steam under pressure (autoclaving). There are two types of tabletop

steam autoclaves:

In most commonly used gravity displacement sterilizers,

steam enters the chamber and unsaturated air is forced out

of the chamber through a vent in the chamber wall.

In contrast, pre-vacuum sterilizers are fitted with a vacuum

pump to create a vacuum in the chamber and ensure air

removal from the sterilizing chamber and load before the

chamber is pressurized with steam. This method improves

the speed and efficiency of the sterilization process.

2) Dry heat sterilizers are either static air (convection or FDA-approved

oven type) or forced air (rapid heat-transfer).

With all of these methods, always use FDA-approved devices and

closely follow the manufacturer’s instructions for proper use.

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Each sterilization process method has time and temperature

parameters that must be followed depending on the type of sterilizer.

Gravity Displacement typical operating temperatures are 30 minutes at

121-123oC (250-254oF) and at 132-135oC (270-275oF).

Tabletop steam sterilizers used most commonly in doctor’s offices and

out-patients settings are compact gravity displacement steam sterilizers

that have a chamber volume of not more than 2 cubic feet and that

generate steam when distilled or deionized water is added.

The prevacuum sterilizer type, because of higher operating

temperatures ranging from 132–135oC (270-275oF) to 141-144oC (285-

291oF) and rapid removal of air, make for a shorter cycle time of 4

minutes.

Dry Heat sterilization has a typical standard cycle of one to two hours

at 170 to 190oC or 320 to 375oF.

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Steam sterilization has several advantages over other types of

sterilization processes including that it is nontoxic; the cycle is easy to

control and monitor with a huge safety margin. It is inexpensive, rapidly

microbicidal and the least affected by contamination with organic or

inorganic soils and penetrates medical packaging and device lumens.

For all these reasons, it is the first choice for use with heat tolerant

medical instruments.

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There are several disadvantages of steam sterilization as well. The

most serious of which is that steam sterilization will destroy heat or

moisture–sensitive instruments and likely damage most heat labile

instruments, which are often complex, and very expensive instruments.

Even heat tolerant items may have dulling or rusting from the steam

sterilization process.

Another important disadvantage is the potential of HCWs getting burns

when handling or removing the instruments from the sterilizer.

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Dry heat sterilizers work by transferring heat energy from air inside the

oven to the instruments. The lack of vapor pressure requires higher

temperatures to achieve sterilization.

Dry heat is good for items that are likely to dull or rust in the autoclave,

and it is good for items like powders, cellulose or ink that require

sterilization.

However, the packaging used must be able to withstand high

temperatures to prevent an accidental fire or charring of contents that

could happen inside the sterilizer.

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There are two types of dry heat sterilizers, static air and forced air. The

static air sterilizer has heating coils in the bottom of the chamber. It

works by natural convection as hot air rises from the coils in the

chamber to reach adequate temperatures. The forced air sterilizer

creates rapid air transfer by circulating heated air throughout the

chamber. The advantage is that the forced air sterilizer has a shorter

cycle time of about 12 minutes as compared to an hour or two for the

static air sterilizer.

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Heat-sensitive instruments that are require sterilization or high-level

disinfection can alternatively achieve this by soaking them in a liquid

chemical sterilant cleared by the FDA. However, exposure to these

powerful and toxic chemicals can be harmful to health care personnel

and patients if the manufacturer’s instructions for use and safety

precautions are not followed precisely. For these reasons, CDC

encourages the use of heat-tolerant or disposable alternatives.

A list of the FDA cleared sterilants and high level disinfectants with label

claims for reprocessing reusable medical devices is available at:

http://www.fda.gov/cdrh/ODE/germlab.html

Photo credit: Col. Shannon Mills, United States Air Force.

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A summary of important recommendations when facilities are

implementing sterilization:

First, steam is preferred for critical items not damaged by heat.

Second, follow the operating parameters recommended by the

manufacturer for the equipment or products used.

Third, use low temperature sterilization technologies for reprocessing

critical items that may be damaged by heat.

And fourth, immediately use critical items that have been sterilized by

an immersion in a chemo-sterilizer solution like glutaraldehyde or OPA.

There should not be long term storage because these items are not

wrapped for protection.

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To review, there are 3 key issues of sterilization . The first, that all

sterilization processes are effective in killing spores, the hardest of

microorganisms to kill.

Second, that cleaning removes salts and proteins and precede all high

level disinfection and sterilization.

And third, that failure to clean or ensure exposure of microorganisms to

sterilants could interfere with the adequacy of the sterilization process.

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Next, we will discuss monitoring. Monitoring the effectiveness of your

sterilization equipment, procedures, and recordkeeping is essential for

patient safety, and mandated by several regulatory agencies (TJC,

CMS, and NC rule .0206).

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The sterilization procedure should be monitored routinely by using a

combination of mechanical, chemical, and biological indicators to

evaluate the sterilizing conditions and indirectly the microbiologic status

of the processed items. The mechanical monitors for steam include the

daily assessment of cycle time and temperature by examining the

temperature record charts or computer readout, and an assessment of

pressure via the pressure gauge.

Chemical indicators usually are either heat or chemical sensitive inks

that change color when one or more sterilization parameters ( e.g.

steam-time, temperature, and or saturated steam) are present.

Biological indicators are recognized by most authorities as being the

closest to the ideal monitors of the sterilization process; because they

measure the sterilization process directly by using the most resistant

microorganisms (i.e. Bacilllus spores) and not merely by testing the

physical and chemical conditions necessary for sterilization.

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Chemical indicators are convenient, are inexpensive, and indicate that the item has been exposed to the sterilization process. Based on current studies, chemical indicators should be used in conjunction with biologic indicators but should not replace them because they indicate sterilization at marginal sterilization time and because only a biologic indicator consisting of resistant spores can measure the microbial killing power of the sterilization process.

Chemical indicators are affixed to the outside of each pack to show that the package has been processed through a sterilization cycle, but these indicators do not prove sterilization has been achieved. Preferably a chemical indicator also should be placed on the inside of each pack to verify sterilant penetration.

Chemical indicators have been grouped into five classes based on the their ability to monitor one or multiple sterilization parameters. If the internal or external indicator suggests inadequate processing, the item should not be used.

If using a prevacuum steam sterilizer, an air-removal test called the Bowie-Dick Test must be performed daily in the empty sterilizer to ensure air removal.

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Biological Indicator are the only process that directly monitor the

lethality of a given sterilization process. Spores used to monitor a

sterilization process have demonstrated resistance to the sterilizing

agent and are more resistant than the bioburden found on medical

devices. Geobacillus stearothermophilus spores (105) are used to

monitor steam sterilization, hydrogen peroxide, gas plasma , and liquid

peracetic acid sterilizers. Bacillus atrophaeus formerly known as

Bacillus subtilis at 106 are used to monitor ETO and dry heat.

Geobacillus stearothermophilus is incubated at 55-60C

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An ideal biological monitor of the sterilization process should be easy to use, be inexpensive, not be subject to exogenous contamination, provide positive results as soon as possible after the cycle so that corrective action may be accomplished, and provide positive only when the sterilization parameters (e.g. steam-time, temperature, and/or saturated steam, ETO time, temperature, relative humidity) are inadequate to kill microbial contamination.

Originally, spore strip biological indicators required up to 7 days of incubation to detect viable spores from marginal cycles. The next generation of biological indicators was self contained in plastic vials containing a spore-coated paper strip and a growth media in a crushable ampoule. This indicator had a maximum incubation of 48 hours but significant failures could be detected in <24 hours. Rapid readout indicators that have been available for more than 10 years, and have been shown to be comparable to that of the conventional biologic indicators.

The standard biological indicator used for monitoring full-cycle steam sterilizers does not provide reliable monitoring of flash sterilizers. Biological indicators specifically designed for monitoring flash sterilization are now available, and studies comparing them have been published.

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Steam and low temperature sterilizers (peracetic acid and hydrogen gas

plasma) should be monitored at least weekly (with the appropriate

commercial preparation of spores). Weekly biological monitoring is a

requirement in the NC Rule .0206

If a sterilizer is used frequently (e.g. several loads per day), daily use of

biological indicator allows for earlier discovery of equipment

malfunctions or procedure errors and thus minimizes the extent of

patient surveillance and product recall needed in the event of a positive

biological indicator.

Each load should be monitored with a biological indicator if it contains

an implantable object. If feasible, implantable items should not be used

until the results of spore tests are known to be negative.

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Since sterilization failure can occur (about 1% for steam) a procedure to follow

in the event of positive spore tests with steam sterilization has been provided

by the CDC and AORN. The positive spore test may occur for reasons such

as slight variations in the resistance of the spore, or improper use of the

sterilizer.

After a single positive biologic indicator test with steam sterilization, remove

and retest the sterilizer. Objects other than implantable object, do not need to

be recalled unless the sterilizer or the sterilization procedure is defective as

determined by maintenance personnel or inappropriate cycle settings are

identified. If additional spore tests remain positive, consider the items non-

sterile and recall. Then reprocess the items from the implicated load(s).

If patient care items were used before retrieval, the infection preventionist

should assess the risk of infection in collaboration with the physician, and if

needed, consult an outside reprocessing specialist. The margin of safety in

steam sterilization is sufficiently large that there is a minimal risk associated

with items in a load that show spore growth, especially if the item was properly

cleaned and the temperature was achieved as demonstrated by a chemical

and readout chart.

After a single positive biological indicator used with a method used other than

steam sterilization, treat as nonsterile all items that have been processed in

that sterilizer, dating from the last sterilization cycle having the last negative

biological indicator. Retrieve items and reprocess.

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As part of a quality control program maintain sterilization records

(mechanical, chemical and biological) for a time period that complies

with standards, for example 3 to 5 years to meet the Joint Commission

visitation schedule and the statutes of limitations, and some state and

federal regulations. Cat II

For each sterilization cycle record the type of sterilizer and cycle used;

the load identification number; the load contents, the exposure

parameters (e.g time and temperature): the operator’s name or initials;

and the results of mechanical, chemical, and biological monitoring. Cat

II

38

Once items are cleaned, dried, and inspected, those requiring

sterilization must be wrapped or placed in rigid containers and should

be arranged in instrument trays or baskets according to the guidelines

provided by AAMI and other professional organizations. These

guidelines state that hinged instruments should be opened; items with

removable parts should be disassembled unless the device

manufacturer or research suggest otherwise. Follow manufacturer’s

instructions for preparing instruments such as concave surfaces placed

downward and heavy items placed below light items to avoid damage.

The wrapping should be done in a manner to prevent gaps and tenting.

There are several choices in products to maintain sterility of surgical

instruments, including the most popular in ambulatory care, the peel

open pouches, also rigid containers, and roll stock that will self seal to

form a pouch and sterile wraps woven and nonwoven. Healthcare

facilities can choose any of these options. The key is the packaging

material must allow penetration of the sterilant, must be compatible with

the type of sterilizer, and must be puncture resistant and durable, and

have received FDA clearance.

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All items to be sterilized should be arranged so that all surfaces will be

directly exposed to the sterilizing agent. Thus the loading procedures

must allow for free circulation of steam (or another agent around each

item. Due to the variety of textiles and containers on the market, the

manufacturers of the sterilizer and wrap or container product should be

consulted on pack preparation and density parameters.

There are several important basic principles for loading a sterilizer:

allow for proper sterilant circulation; perforated trays should e placed on

their edge (e.g basins); small items should be loosely placed in wire

baskets; and peel packs should be placed on edge in perforated or

mesh bottom racks or baskets.

40

A summary of recommendations for sterilization include that steam is

preferred for critical and semi-critical items that are not damaged by

exposure to high heat.

It is vital to always follow the manufacturer’s operating instructions for

sterilizers and products, and equipment.

It is also important to use ―FDA cleared‖ containers, wrapping, or

packaging system that is compatible with the type of sterilization

process used.

And it is critical for successful sterilization to not overload the sterilizer

chamber.

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Next we will review CDC recommendations for storage of sterile items.

The sterile storage area should be a well-ventilated area that provides

protection against dust, moisture, and temperature and humidity

extremes. Sterile supplies should be stored far enough from the floor (8

to 10 inches), the ceiling (5 inches unless near a sprinkler head or18

inches from the sprinkler head), and outside walls (2 inches) to allow for

adequate circulation, ease of cleaning, and compliance with fire codes.

Store sterile items so the packaging is not compromised (e.g.,

punctured, bent). Sterilized items should be labeled with a load number

that indicates the sterilizer used, the cycle or load number, the date of

sterilization, and the expiration date (if applicable).

Closed or covered cabinets are ideal but open shelving may be used for

storage. Any package that has fallen on the floor must be inspected for

damage to the packaging and contents. If the package is heat-sealed in

impervious plastic and the seal is still intact, the package should be

considered not contaminated. If undamaged, items in packaged plastic

need not be reprocessed.

42

The shelf life of a packaged sterile item depends on the quality of the

wrapper, the storage conditions, the conditions during transport, the

amount of handling, and other events like exposure to moisture that

compromises the integrity of the package. If event-related storage of

sterile items is used, then packaged sterile items can be used

indefinitely unless the packaging is compromised. Packages should

always be inspected and evaluated before use for loss of integrity (e.g.

torn, punctured, or wet) If the integrity of the package is compromised,

repack and reprocess the pack before use.

Time related storage considers items remain sterile for varying periods

depending on the type of material used to wrap the item/tray. If time-

related shelf life (less common) is used, label the pack at the time of

sterilization with an expiration date. Once the expiration date is

exceeded the pack should be reprocessed.

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Recommendations for quality control are to provide comprehensive and

intensive training for all staff assigned to reprocess semi-critical and

critical medical/surgical devices to ensure they understand the

importance of reprocessing these instruments. To ensure and maintain

competency, 1)train each member of the staff who reprocesses semi-

critical and/or critical instruments as follows; 2) provide hands on

training according to facility policy for reprocessing; supervise all work

until competency is documented for each reprocessing task, 3) conduct

competency testing at the beginning of employment and regularly

thereafter (for example annually), and 4) review the written

reprocessing instructions regularly to ensure they comply with the

scientific literature and manufacturer’s instructions.

To assist NC healthcare facilities, a sample competency monitoring tool

for reprocessing developed by UNC Healthcare System is included in

the handouts.

44

As part of the quality control program, conduct infection control rounds

periodically, minimally annually, in high risk reprocessing areas ( e.g.

Gastroenterology or Endoscopy Clinics) to ensure reprocessing

instructions are current and accurate and are correctly implemented.

Include a sterilizer maintenance contract with records of service, a

system of process monitoring, visual inspection of packing materials,

and traceability of load contents. Perform preventive maintenance on

sterilizers by qualified personnel who are guided by the manufacturer’s

instructions.

Periodically review policies and procedures for sterilization to ensure

that they are current with guidelines.

Consult AAMI and or the manufacturer for correct preparation and

wrapping materials that may be used with sterilizer.

45

In the past two decades, newly emerging or remerging diseases have

created some concerns as to whether healthcare facilities should do

more or do something different with disinfection and sterilization of

equipment and instruments used on patients known or suspected of

having these emerging pathogens.

46

This is a fairly comprehensive list of the emerging pathogens reported

or that may have a potential to be in the US. There is hepatitis C that

can survive in the environment for at least a couple weeks, and that it is

not more resistant to cleaning and disinfection than hepatitis B.

However, Clostridium difficile because of its ability to be a spore former

in the environment is resistant to alcohol-based hand rubs and nearly all

surface disinfectants except those containing a 1:10 dilution of bleach.

Cryptosporidium and Helicobacter pylori and E. coli 0157:H7 have

contaminated water systems from farm animal runoff. There are

multidrug resistant pathogens prevalent in healthcare. The pathogens

that have been the source of outbreaks in the community and

healthcare facilities are SARS, coronavirus, avian influenza, and

norovirus. And there is even the potential of the bioterrorism agents

including anthrax, plague, and smallpox.

47

For all the these emerging pathogens just listed, healthcare facilities

can use standard disinfection and sterilization procedures for patient

care equipment which is adequate to sterilize or disinfect instruments or

devices contaminated with blood and other body fluids from persons

infected with these emerging pathogens.

48

Only one disease is an exception to being eradicated by normal

disinfection, and that is Creutzfeldt-Jakob Disease or CJD. There are

other neurologic diseases that are also caused by prions such as

scrapie.

Creutzfeldt-Jacob Disease (CJD) and other prion diseases are rare,

fatal diseases of the central nervous system characterized by rapid,

progressive dementia and other sensory and motor disturbances.

CJD is thought to be caused by small, abnormal pieces of protein

referred to as prions. Prions occur naturally in mammals and birds but

turn destructive when they become folded in a way that changes how

they react with other brain chemicals.

CJD has an extremely long incubation period and is fairly rare with only

one case per million worldwide reported.

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A new variant of CJD (vCJD), the human version of Bovine Spongiform

Encephalopathy (BSE), was recognized after what has become known

as Mad Cow Disease occurred from changes made in the processing of

food for bovines in Great Britain. Several hundred people to date have

been reported, mostly in the UK, Italy, France, Hong, and Canada which

is waning in number of new cases, since the food processing practices

were changed. One case reported in the US is a former UK resident.

50

Because of the devastating nature of this rare degenerative neurologic

disorder caused by a prion. The CJD does not appear to be

epidemiologically related by disease by age or sex, has no seasonal

distribution, and no geographic aggregation that cannot be accounted

for from a reservoir. Although the disorder has a very long, probably

several years in length, incubation period, once the individual becomes

symptomatic there is a rapid progression of serve symptoms and death.

Importantly to this discussion prions, although extremely rare, are

resistant to conventional disinfection and sterilization reprocessing.

51

High risk tissues include: brain, spinal cord, and posterior eye (retina

and optic nerve). All other tissues are considered low or no risk. If the

patient is identified with a neurologic disorder of unknown etiology and

has a procedure involving the high risk tissues with critical or semi-

critical equipment, then keep the equipment in a closed container or bag

until consultation from reprocessing experts or SPICE can be obtained

for the appropriate evaluation and methods for handling and

reprocessing.

52

Thank you for your time and attention. This concludes Section E,

Sterilization and Disinfection. The next slide contains important

references that were used in the development of this Section.

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