Microbial control Flashcards
free of life of every kind
Sterile
the process of complete removal or destruction of all forms of microbial life which may be effected by physical or chemical means
Sterilization
having the property of inhibiting bacterial growth or multiplication
▪ Bacteriostatic
having the property of killing or destroying bacteria
Bactericidal
the process of killing or removing microorganisms on inanimate surfaces through the use of chemical agents
Disinfection
a chemical substance used to kill infection- producing microorganisms on surfaces but too toxic to be applied directly to tissues
Germicide or Disinfectant
characterized by the presence of pathogenic microbes in living tissues
Septic
characterized by the absence of
pathogenic microbes
Aseptic
a chemical substance which opposes sepsis or putrefaction either by killing microorganisms or by preventing their growth; applied topically to living tissues
Antiseptic
that temperature which in a given time destroys all the bacteria present
Thermal Death Point
- minimum time required to kill a suspension of organisms at a given temperature in a specified environment
Thermal Death Time
Period of adaptation; little or no multiplication but active metabolically
Lag Phase (Phase of Rejuvenescence or
Phase of Physiologic Youth
Organisms grow at maximum rate
Logarithmic Phase (Exponential Phase)
Rate of cell reproduction equals the rate of cell death
Stationary Phase (Plateau Phase or
Phase of Equilibrium)
- Total number of viable cells in the population decreases as cells die off at a constant rate
Death Phase (Phase of Decline
▪ aka. Clean Technique
▪ involves procedures and practices that reduce the number and transmission of pathogens
Medical Asepsis
▪ aka. Sterile Technique
▪ includes practices used to render and keep objects and areas sterile (free from microorganisms)
Surgical Asepsis
Easy to obtain and inexpensive; rapid
evaporation limits their contact time
Alcohols
Capable of destroying all forms of microbial life. Irritating to the respiratory tract, skin, and eyes
Aldehydes
(Formaldehyde)
Relatively low toxicity, destroys a wide range of microbes, adheres to and persists on skin and mucous membranes
Biguanides(Chlorhexidine)
Easily penetrates hard- to- reach places and fabrics and does not damage moisturesensitive material. It is toxic, explosive, and potentially carcinogenic
Ethylene Oxide Gas
Chlorine solutions are inexpensive and readily available however, organic compounds and other impurities neutralize the activity. Iodine is more expensive than chlorine and does not reliably kill endospores
Halogens (Chlorine and Iodine)
Most metal compounds are too toxic to be used medically
Metals (Silver
This unstable form of molecular oxygen readily breaks down
Ozone
Readily biodegradable and less toxic than traditional alternatives. The effectiveness of hydrogen peroxide as an antiseptic is limited because the enzyme catalase breaks it down. Peracetic acid is more potent germicide than is hydrogen peroxide.
Peroxygens (hydrogen peroxide and peracetic acid)
Wide range of activity, reasonable cost, remains effective in the presence of detergents and organic contaminants, leaves an active antimicrobial residue
Phenolic Compounds (triclosan and hexachlorophene)
Non- toxic enough to be used on food preparation surfaces. Inactivated by anionic soaps and detergents.
Quaternary Ammonium Compounds (benzalkonium chloride and cetylpyridium chloride)
Most microorganisms are not killed by cold temperatures and freezing but their metabolic activities are slowed, inhibiting their growth
Cold
▪ freeze- drying
▪ used to preserve foods, antisera, toxins, antitoxins, antibiotics, and pure culture of microorganisms
Lyophilization
▪ Definition by the CDC in 1996
▪ used for the care of all hospitalized patients, regardless of their diagnosis or presumed infection status
Standard Precautions
▪ infection control techniques that were recommended following the AIDS outbreak in
1980s
▪ a set of precautions designed to prevent the transmission of HIV, HBV and other
blood- borne pathogens when providing first aid and healthcare
Universal Precautions
designed for patients known or suspected to be infected with highly transmissible or epidemiologically important pathogens for which additional precautions beyond Standard Precautions are required to interrupt transmission within hospitals
Transmission- based
Precautions
involves either airborne droplet nuclei or dust particles containing a pathogen
Airborne Precautions
are small- particle residue (5 um or less in diameter) of evaporated droplets containing microorganisms; they remain suspended in air for long periods
*Airborne droplet nuclei
▪ Use private room that has:
▪ Monitored negative air pressure,
▪ 6- 12 air changes per hour,
Patient Placement
▪ Wear an N95 respirator when entering the room of a patient with known or suspected infectious pulmonary tuberculosis
Respiratory Protection
▪ Limit transport of patient from room to essential purposes only
▪ Use surgical mask on patient during transport
Patient Transport
produced primarily as a result of coughing, sneezing, and talking, as well as during hospital procedures such as suctioning and bronchoscopy
Droplets
resistant pneumococcal meningitis or pneumonia Whooping cough
Multidrug
▪ Private room.
▪ If a private room is not available, the patient may be placed in a room with a
patient having active infection with the same pathogen but with no other
infection (Cohort).
Patient Placement
Persons working within 3 feet of the patient must wear a mask (or upon entering the room)
Mask
Limit transport to essential purposes only. Use surgical mask is placed on the
patient during transport.
▪ Patient Transport
Contact transmission is the most important and frequent mode of transmission of nosocomial infections
Contact Precautions
▪ transfer of microorganisms by body surface- to- body surface contact
Direct- contact transmission
▪ transfer of microorganisms via a contaminated intermediate object (FOMITE), such as instruments, needles, and dressings
▪ Indirect- contact transmission
▪ Gloves are worn when entering the patient’s room. ▪ Change gloves after having contact with infective material that may contain high concentration of microorganisms (fecal material and wound drainage).
Gloves
Wash hands with antimicrobial agent immediately after glove removal.
Wash
Wear a gown when entering the patient’s room if you anticipate that your clothing will have substantial contact with the patient, environmental surfaces, or items in the patient’s room or if the patient
▪ Gown
▪ Dedicate the use of noncritical patient- care equipment to a single patient.
▪ If common equipment is used, clean and disinfect between patients.
Patient- Care Equipment
▪ placing into isolation patients with tuberculosis or other contagious diseases to protect other people from becoming infected
Source Isolation
▪ aka. Reverse Isolation or Neutropenic Isolation
▪ placing patients who are vulnerable to infection in a total protective environment (TPE)
Protective Isolation
▪ includes private room where vented air entering the room is passed through HEPA
filters.
▪ The room is under positive pressure to prevent the hallway air from entering when
the door is opened.
▪ The room must be thoroughly cleaned and disinfected before the patient is
admitted.
▪ All items coming in contact with the patient must be disinfected or sterilized.
Total Protective Environment (TPE)
widely used to sterile medical instruments
Glutaraldehyde
used in vaccine preparation
Formalin
widely used as an antiseptic in soaps and lotions, and more recently, impregnated into catheters and surgical mesh
Chlorohexidine
Commonly used to sterilize medical devices
Ethylene Oxide Gas
are inexpensive and readily
available however, organic compounds and
other impurities neutralize the activity
Chlorine solutions
is more expensive than chlorine and
does not reliably kill endospores
Iodine
used in topical dressings to prevent infection of burns
Silver Sulfadiazine
drops can be used to
prevent eye infections caused by N. gonorrheae in
newborns.
Silver Nitrate
used to sterilize containers for
aseptically packaged juices and milk.
Hydrogen Peroxide
is widely used to disinfect and sterile medical devices
Peracetic acid
used in a variety of personal care products, including toothpaste, lotions and deodorant soaps
Triclosan
is highly effective against Staph.
aureus, but its use is limited because it can cause
neurological damage
Hexachlorophene
Quaternary Ammonium Compounds
benzalkonium chloride and cetyl peridium chloride
