Transcript Cleaning/decontamination, disinfection, and sterilization

Cleaning/decontamination,
disinfection, and sterilization
Kumthorn Malathum, MD
Chair, ICC, Ramathibodi Hospital
Scope
Cleaning/decontamination, disinfection,
and sterilization of medical devices
 Environmental cleaning

Routine: floor, bed rail, etc.
 MDR bacteria
 Respiratory pathogens (virus, mycobacteria)

Virulence is not
Certain enveloped (lipophilic)correlated
viruses
with
(e.g., HSV, HIV, influenza virus, and
RSV are susceptible to alcohols.
the
ease
to
be
Hepatitis B virus is an enveloped virus
that is somewhat less susceptible
but
destroyed!
is killed by 60%–70% alcohol; hepatitis
C virus also is likely killed by this
percentage of alcohol.
APIC guidelines Am J Infect
Control 1996:24;313-42
Cleaning
Removing all foreign material from objects
by using water and detergents or soaps
and washing or scrubbing the object
 Must be done before any disinfection or
sterilization process

Disinfection
A process that eliminates many or all
microorganisms except spores
 Done with liquid chemicals or by
pasteurization
 Proper contact time and dilution of the
disinfectant must be followed

Definitions

High-level disinfection


All microorganisms except high numbers of
bacterial spores
Intermediate disinfection

M. tuberculosis, vegetative bacteria, most
viruses, and most fungi
 Not necessarily kill bacterial spores
Sterilization

A process that completely eliminates or
kills all microorganisms
Classification of device, process, and products
Device
Process
Product
Classification
Examples
Critical
Implant, surgical
instrument
Sterilization
Sterilant/disinfectant
Semicritical
Flexible endoscope,
laryngoscope,
endotracheal tube
High-level
Sterilant/disinfectant
Thermometer,
hydrotherapy tank
Intermediate Hospital disinfectant
-level
with tuberculocidal
activity
Noncritical
Stethoscope,
Low-level
tabletops, bedpans
Sterilant/disinfectant
without tuberculocidal
activity
Chemical disinfection
Aldehydes: glutaraldehyde & orthophthaldehyde (OPA)
 Alcohol
 Biguanides: chlorhexidine
 Halogen and halogen releasing agents:
chlorine, iodine
 Quaternary ammonium compound

Glutaraldehyde
High-level disinfectant
 Working solution pH 7.5 to 8.5, 14 to 28 days
 Mode of action: cross-linking with proteins,
inhibit synthesis of DNA, RNA
 2%: vegetative bacteria < 2 minutes, M.
tuberculosis, fungi, viruses < 10 minutes,
spore of Bacillus & Clostridium spp. 3 h
 Use: medical equipment
 Toxic: respiratory system

Glutaraldehyde

Advantages
Rapid low-temperature disinfection
 OPA has greater anti-mycobacterial activity,
no activation required, less noxious, more
stable


Disadvantages
Irritating
 Absorbed into plastics leads to toxicity (e.g.,
colitis)

Alcohol
Optimal conc. 60% to 80%
 Not HIGH level (spores and hydrophilic
virus are not destroyed)
 Use: oral and rectal thermometers, small
surfaces (multiple dose medication vials),
external surface of equipment
(stethoscope, ventilators, manual
ventilation bags)

Biguanides

Chlorhexidine (bisbiguanide)
Insoluble in water
 Active against Gm +ve > Gm –ve bacteria >
yeasts & molds
 Not sporicidal
 Can be inactivated by nonionic surfactant
presented in soaps, hand creams, and
inorganic water contaminants (phosphate,
chlorine)

Chlorine compound

Concentration dependent:
25 ppm: mycoplasma and vegetative bacteria
(<1 ppm) within seconds
 100 ppm: Bacillus subtilis spores within 5
minutes, fungus < 1 h
 1000 ppm: M. tuberculosis


Household bleach 5.25% = 52,500 ppm
Iodophors
Tincture of iodine
 7.5% Povidone-iodine (PVP-I), 0.7%
available iodine

Bactericidal, fungicidal, tuberculocidal, and
virucidal
 Short time residual effect

Quaternary ammonium compound:
benzalkonium chloride
Associated with many outbreaks including
non-tuberculous Mycobacterium & GNR
 Not recommended for use as skin and
tissue disinfectant
 Use: environmental sanitation of
noncritical surfaces (floors, furniture, walls)

Problems associated with the
use of disinfectants
Ineffective cleaning
 Too low concentration


Contaminants unlikely to survive in
recommended use-dilution
The amount of use and costs of
antiseptics/disinfectants per bed per year
Danchaivijitr S et al. J Med Assoc Thai 2005; 88 (Suppl 10): S133-9
Places where antiseptics/disinfectants
were prepared
Danchaivijitr S et al. J Med Assoc Thai 2005; 88 (Suppl 10): S133-9
Persons who prepared
antiseptics/disinfectants used in wards
Danchaivijitr S et al. J Med Assoc Thai 2005; 88 (Suppl 10): S133-9
Microbial contamination (%)
Danchaivijitr S et al. J Med Assoc Thai 2005; 88 (Suppl 10): S133-9
Danchaivijitr S et al. J Med Assoc Thai 2005; 88 (Suppl 10): S133-9
Infection control in flexible
endoscopy
Alvarado C et al. Am J Infect Control 2000;28:138-55.
Agents recommended for high-level
disinfection of flexible endoscopes
Glutaraldehyde preparations
 Peracetic acid
 Orthophalaldehyde

Alvarado C et al. Am J Infect Control 2000;28:138-55.
Agents not recommended for
disinfection of flexible endoscopes
Hypochlorites
 Quaternary ammonium compounds



Not sporicidal, tuberculocidal, or viricidal
against hydrophilic viruses
Phenolics

Intermediate-level disinfectants
Alvarado C et al. Am J Infect Control 2000;28:138-55.
Disinfection of a Probe Used in
Ultrasound-Guided Prostate Biopsy
Rutala WA., et al. Infect Control Hosp Epidemiol 2007; 28:916-919
Main findings

Disinfection (i.e., a reduction in bacterial
load of greater than 7 log10 CFU) could be
achieved if the needle guide was removed
from the probe
Rutala WA., et al. Infect Control Hosp Epidemiol 2007; 28:916-919
Main findings

If the needle guide was left in the probe
channel during immersion in 2%
glutaraldehyde, disinfection was not
achieved (i.e., the reduction was
approximately 1 log10 CFU)
Rutala WA., et al. Infect Control Hosp Epidemiol 2007; 28:916-919
Treatment of endoscope after
disinfection or sterilization

Rinsing
Sterile water
 Alcohol rinse followed by complete drying
 Only sterile water should be used for
endoscopes that pass through sterile tissues.

Alvarado C et al. Am J Infect Control 2000;28:138-55.
Treatment of endoscope after
disinfection or sterilization

Drying


Drying with alcohol and compressed air
should be done between each patient use
when tap water is used to rinse the
endoscope channels and before storage
whether tap water or sterile water is used.
Storage
Alvarado C et al. Am J Infect Control 2000;28:138-55.
Sterilization

Heat sterilization
Dry heat
 Moist heat: pressure steam sterilizer
(autoclave)


Chemical
Ethylene oxide
 Glutaraldehyde

Autoclave
Steam must come into direct contact with
the surface
 Air must be completely removed

Downward displacement
 Pre-vaccuum

Flash sterilization
Steam sterilization of patient care items for
immediate use
 Not for convenience or an alternative to
purchasing additional instrument sets or to
save time
 Not recommended for implantable devices

Flash sterilization

Lack of timely biologic indicators to
monitor performance, absence of
protective packaging following sterilization,
possibility for contamination of processed
items during transportation to operating
rooms, and use of minimal sterilization
cycle parameters (i.e., time, temperature,
pressure)
Parameters for flash sterilization
Ethylene oxide
Extremely penetrative
 Non-corrosive
 Toxic, irritant, and explosive when mixed
with air at conc. >3%
 Odorless

Quality assurance for sterilization

Mechanical monitoring
Exposure time, temperature, and pressure
 Ascertain that the sterilization system function
within parameters


Chemical monitoring
Does not verify sterilization
 Indicate procedural errors and equipment
malfunction

ความถี่ในการตรวจสอบ
Mechanical
monitoring
ทุกครั้งที่ทาการอบ
External chemical ทุกห่อยกเว้นถ้าสามารถมองเห็นตัวบ่งชี้
indicators
ทางเคมีภายในได้ชัดเจน
Internal chemical
indicators
Biological
monitoring
ทุกห่อถ้าปฏิบัติได้
ควรใส่ในห่อขนาดใหญ่และห่อ
เครื่องมือผ่าตัด
Daily or at least weekly
AAMI ,AORN ,CDC,CSA
Definition of a chemical indicators

CI – System that reveals a change in one
or more predefined process variables
based on a chemical or physical change
resulting from exposure to a process.
CI classes

Class 1 – Process Indicators

Used to show exposure to a process. No
information about the success or failure of the
process
Class 2 – Specific Test Indicators (e.g.
BDT)
 Class 3 – Single variable indicators


Respond to a single variable in the process
e.g. temperature
CI classes

Class 4 – Multivariable Indicators


Respond to two or more variables in the
process
Class 5 – Integrating Indicators (Chemical
Biological Indicators)

Respond in a way which mimics the response
of a BI if used in the same process
CI classes

Class 6 – Emulating Indicators (Cycle
Verification Indicators -Chemical Chart
Recorders)

Respond to all critical variables of the process
at levels associated with acceptable sterilizing
conditions e.g. 134 for 5 mins.
Quality assurance for sterilization

Bowie-Dick test
Performed daily, with pre-vacuum system, in
an empty chamber
 Detect residual air in the sterilizer chamber

Biologic monitoring of steam
sterilization
Biologic indicators demonstrated bacterial
growth from spore strips on 15 (12%) out
of 125 cycles
 Chemical indicators revealed a change of
color to black after all 125 cycles

Kelkar U et al AJIC 2004, 512-513
BI – changes
Bacillus subtilis renamed to B. atrophaeus
 Bacillus stearothermophilus renamed to
Geobacillus stearothermophilus

QA for sterilization
Whenever sterilizers are used, they should
be routinely tested with biological
indicators to ensure they are working
correctly
 Items that are sterilized should remain
sterile until the package is torn, wet, or
damaged. Sterility is a function of intact
packaging, not time.

ขั้นตอนการตรวจสอบด้ วยสปอร์ เทสต์
นาสปอร์เทสต์มาทาการอุ่นเชื้อในเครือ
่ งอุ่นเชื้อที่
สามารถควบคุมอุณหภูมิให้มีความเหมาะสมใน
การเจริญเติบโตได้ดี
Steam 56  1o C
EtO 37  1 o C
การอ่านผลการตรวจสอบ
ตรวจดูการเปลี่ยนแปลงสีของน้าเลี้ยงเชื้อทุก 8,
12, 24 และ 48ชม
 การเปลี่ยนแปลงสีเป็นสีเหลืองแสดงว่าการทาให้
ปราศจากเชื้อไม่สมบูรณ์เชื้อโรคถูกฆ่าตายไม่
หมด
 ไม่มีการเปลี่ยนแปลงสีแสดงว่าการทาให้
ปราศจากเชื้อสมบูรณ์เชื้อโรคถูกฆ่าตายหมด

การอ่ านผล
Successful
Sterilization
Process
Failed
Sterilization
Process
อ่านผล จากการเปลี่ยนแปลงสีของน้าเลี้ยงเชื้อ
ภายหลังการอุ่นเชื้อที่ 8, 12, 24, 48 ชั่วโมง ถ้ามีการ
เปลี่ยนแปลงสีเป็นเหลืองให้ทาการอ่านผลได้เลย
ปัญหาที่พบบ่อย
แช่ก่อนล้าง
 แช่ของที่ควรนึ่ง หรืออบแก๊ส
 การระบายอากาศในห้องที่ใช้ Glutaraldehyde
ระบบการตรวจสอบการทางานของเครื่องนึ่ง/
เครื่องอบแก๊ส
 โครงสร้าง

บุคคล
 สถานที่
