Page 111 - Review of Medical Microbiology and Immunology ( PDFDrive )

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13
C
R
T
P
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Sterilization & Disinfection

Modification of Proteins mebooksfree.com
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mebooksfree.com mebooksfree.com PHYSICAL AGENTS mebooksfree.com mebooksfree.com
CHAPTER C ONTENT S

STERILIZATION, DISINFECTION, AND STANDARD
PRECAUTIONS
Heat
Radiation
PRINCIPLES OF STERILIZATION & DISINFECTION
Filtration
RATE OF KILLING OF MICROORGANISMS
Pearls
CHEMICAL AGENTS
Disruption of Cell Membranes
Practice Questions: USMLE & Course Examinations
Modification of Nucleic Acids Self-Assessment Questions
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STERILIZATION, DISINFECTION, AND

STANDARD PRECAUTIONS

The purpose of sterilization and disinfection procedures is
to prevent transmission of microbes to patients. In addition
should be specific for the task rather than for the particular
to sterilization and disinfection, other important measures
to prevent transmission are included in the protocol of
In addition, there are transmission-based precautions
that supplement the standard precautions and should be
“standard precautions” (previously known as Universal
Precautions).These standard precautions should be used in patient.
employed when the patient is infected (or suspected to be
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infected) with a highly transmissible organism. The three
interaction with all patients because it is unknown whether
categories of transmission-based precautions are contact,
any particular patient may be the reservoir of transmissible
bacteria, viruses, or other microbes.
droplet, and airborne. Table 13–1 describes some of the
Standard precautions include (1) hand hygiene, (2) respira-
tory hygiene and cough etiquette, (3) safe injection practices,
tional information, please consult the CDC Web site
and (4) proper disposal of needles and scalpels. Further, if
<http://www.cdc.gov/hai/>, where health care associated
exposure to body fluids or aerosols is likely, personal protective
infections (HAI) are discussed.
equipment (PPE) such as masks or face shields, gloves, gowns,
PRINCIPLES OF STERILIZATION & DISINFECTION
Sterilization is the killing or removal of all microorgan- organisms. For adequate disinfection, pathogens must be
Disinfection is the killing of many, but not all, micro-
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mebooksfree.com mebooksfree.com mebooksfree.com erties from the corrosive phenol-containing compounds, mebooksfree.com
isms, including bacterial spores, which are highly resistant.
killed, but some organisms and bacterial spores may
Sterilization is usually carried out by autoclaving, which
consists of exposure to steam at 121°C under a pressure of
survive. Disinfectants vary in their tissue-damaging prop-
2
15 lb/in for 15 minutes. Surgical instruments that can be
damaged by moist heat are usually sterilized by exposure to
which should be used only on inanimate objects, to less
ethylene oxide gas, and most intravenous solutions are
toxic materials such as ethanol and iodine, which can
sterilized by filtration.
be used on skin surfaces. Chemicals used to kill
100
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