Control of Microorganism Flashcards
introduced the concept of aseptic surgery using carbolic acid.
Joseph Lister
Complete destruction of all forms of life, including
bacterial spores
Sterilization
Sterilization can be achieved with the use of what?
High pressure, heat, and chemicals
A process that eliminates a defined scope of microorganisms, including some spores.
Disinfection
is sterilization selective or nonselective?
non selective
is disinfection selective or non selective?
selective
are chemical agents applied to inanimate objects.
Disinfectants
a substance applied to the skin for the purpose of eliminating or reducing the number of bacteria present. However, it does not kill spores.
antiseptic
Microorganisms living together in communities and
provides protection to the microorganisms against
chemical and physical means of destruction
Biofilm
Naked pieces of protein and thought to be the agents
that cause a number of degenerative diseases of the
nervous system
Prions
Prions can withstand high temperature. Give the value
More than 121 degrees Celsius
When an object or material is thought to be contaminated with a prion, special methods need to
be taken to destroy the agent. Simple disinfection or
sterilization may not be sufficient. True or False?
True
Enumerate the different types of organisms according to most resistant to least resistant.
Prions - Bacterial spores - mycobacteria - nonlipid viruses - fungi - bacteria - lipid viruses
The total number of organisms present.
Microbial load
Composed of organisms with differing degrees of
susceptibility to killing agents, all the organisms
die at the same time. True or false?
False - not all organisms die at the same time.
If the number of organisms is plotted against the
time they are exposed to the killing agent
(exposure time) logarithmically, the result is a
straight line. The straight line is called?
The death curve
Higher numbers of organisms require longer or shorter exposure times?
Longer exposure times
what disinfectant may actually allow microorganism to survive because it is not enough to kill microorganism?
Povidone-iodine
what organic material affects the killing activity by inactivating disinfecting agent?
blood, mucus, and pus
Alcohol and iodine preparations (e.g., Betadine) must be
in contact with an object for at least?
1-2 minutes
What is the temperature of disinfectants?
20 - 22 degrees Celsius
Considered a community of bacteria or other
microorganisms.
Biofilms
What place in the hospital is where biofilms commonly seen?
Catheters
What materials that invade sterile tissues or enter the vascular system. These materials are most likely to produce infection if contaminated, and they require sterilization.
Critical materials
before they come contact they require high level of disinfection agents
semi critical materials
require intermediate-level to
low-level disinfection before contact with intact skin
non critical materials
the most common method used for elimination of microorganisms
heat
it is the agent used in autoclaves
moist heat
give the values of autoclaves
121 degrees , 15 minutes at 15 PSI
It requires much longer exposure times
and higher temperatures than moist heat.
Dry heat
This method may be used for heat-stable
substances that are not penetrated by moist
heat, such as oils.
Dry heat
commonly used physical methods to sterile glassware
dry heat
Methods that achieve disinfection but not
sterilization; these
boiling and pasteurization
what is the temperature of boiling and pasteurization
72 degrees or 121 F for 15 seconds
physical method that May be used with both liquid and air
Filtration
filtration is accomplished by
HEPA or High efficiency particulate air
Identify the physical method
Short wavelength and high energy
- For the sterilization of disposable supplies
such as syringes, catheters, and gloves
Ionizing radiation
Identify the physical method
- Long wavelength and low energy
- it damages DNA by forming _ and _
- usefulness is limited
non ionizing wavelength
One of the most important contributions by
microbiologists to the general welfare of the
worldwide population
Germ theory of disease
Two most effective alcohols used in hospitals for disinfection purposes are?
Ethyl alcohol and isopropyl alcohol
Alcohols are not sporicidal solutions, alcohol may actually
be contaminated with spores. True or false?
True
use as disinfectant of biosafety hoods?
formaldehyde
what disease has been known to survive for many years in tissue fixed in formaldehyde?
tuberculosis
Saturated five-carbon dialdehyde that has
broad-spectrum activity and rapid killing action and remains active in the presence of organic
matter
Glutaraldehyde
Extremely susceptible to pH changes and is
active only in an alkaline environment. Formaldehyde or Glutaraldehyde?
Glutaraldehyde
are alcohol and iodine solutions, used
mainly as antiseptics
Tincture
is a combination of iodine and a neutral
polymer carrier that increases the solubility of the agent. This combination allows the slow release of
iodine.
Iodophor
Commonly used as skin preparation agents for sites
where blood is to be drawn for blood cultures.
Iodophors
Some of the oldest and most commonly used disinfectants.
chlorine compounds
It has been used for more than 30 years in hospital settings.
Chlorhexidine gluconate
Chlorhexidine gluconate is more effective in what gram stain?
gram positive
Primarily effective against gram-positive bacteria.
Hexachlorophene
it has good activity against gram-positive bacteria, but it is less
active against gram-negative bacteria, M. tuberculosis,
fungi, and viruses
chloroxylenol
A diphenyl ether that disrupts the cell wall
Triclosan
triclosan has fair activity against ____ and poor activity against ____
M. tuberculosis; Fungi
it is rarely used in clinical application
heavy metals
first solid surface that get the approval of EPA to be considered antimicrobial for health care use
Copper and copper alloys
gas most commonly used for sterilization
ethylene oxide
what relative humidity is use in ethylene oxide in order to kill spores?
30%
Primarily used as a sterilant in the pharmaceutical
and medical device manufacturing industries.
Hydrogen peroxide
hydrogen peroxide is active against?
bacterial endospores and fungal spore
The main goal of handwashing is to eliminate
transient biota
used to stop the spread of infectious agents that may be transmitted through direct or indirect
contact with the patient or with the patient’s
environment.
Contact precautions
used to stop the spread of infectious agents that can be transmitted by close respiratory contact
or by exposure of mucous membranes to
respiratory secretions
Droplet precaution
These precautions are used for infectious
agents, such as M. tuberculosis, varicella virus, and rubeola virus, that can remain airborne and infectious over long distances
Airborne precautions
is an important part of every microbiology laboratory safety program
Biological risk assessment
has long been known to cause tuberculosis in laboratory workers exposed to aerosols
created in processing sputum samples
M. Tuberculosis
other infectious
agents that can be transmitted through inhalation of an
aerosol created during the processing or handling of
specimens (e.g., blood that may harbor these organisms)
or cultures of the organism
Brucella spp. and Francisella tularensis
the most infectious fungus, can
infect several people in a room if culture plates on which
the organism is growing are not sealed with tape or are
open in the absence of a biosafety hood
coccidiodes immitis
A common practice is to perform all specimen processing in a because of the
uncertainty regarding the infectious agents that
might be present in the sample.
biosafety cabinet
what class of BSC uses an exhaust fan to move air inward through open front?
Class I
what class is the most common in microbiology lab where air is pulled inward and downward by a blower and passed up through the air flow plenum
Class II
what class is a self contained ventilated system for highly infectious microorganism or materials
Class III
what biosafety level where infectious agents are classified that are not known to cause disease and pose minimal threat to lab personnel and environment?
biosafety level I
Bacillus subtilis ,
Naegleria gruberi and Enterobacter aerogenes. What biosafety level?
biosafety level I
what biosafety level where infectious agent that poses a
moderate potential hazard?
biosafety level II
HBV, HIV,
Salmonella spp., and Toxoplasma gondii)
What biosafety level?
biosafety level II
what biosafety level where Infectious agents that are either
indigenous or exotic. These agents have the potential for aerosol transmission, and diseases with
these agents may have serious lethal
consequences. Laboratory personnel must have specific training in handling these pathogenic and
potentially lethal organisms.
Biosafety level III
M. tuberculosis,
St. Louis encephalitis virus, and Coxiella burnetii.
What biosafety level?
biosafety level III
what biosafety level where infectious agents that are
dangerous and exotic. These agents have a high risk of causing life-threatening infections, can be
transmitted by aerosols, or have an unknown risk of
transmission?
biosafety level IV
Marburg virus and
Congo-Crimean hemorrhagic fever viruses.
What biosafety level?
Biosafety level IV
are provided by the manufacturer or distributor for
hazardous chemicals.
SDS ( safety data sheet )
chemical should be stored alphabetically. True or False?
False - it must be stored according to establish rules of compatibility
must not be
stored with carbon dioxide, chlorinated hydrocarbons, or
water.
Alkali metals
must never be stored together
acids and bases
should never be stored
with oxidizing agents.
acetic acid and sulfuric acid
are incompatible with ammonia, acetylene,
and hydrocarbons
Halogen
are one of the most important
pieces of equipment for the protection of workers from
exposure to hazardous chemicals
Laboratory fume hoods
are among
the biggest sources of fire hazards in the clinical
microbiology laboratory
bunsen burners and open flame burner
Agents pose the greatest public health threat because they are easily transmitted and are
highly infectious
Category A
Agents have moderate morbidity and low
mortality and are not as easily transmitted
as category A agents
Category B
Agents are classified as emerging pathogens
Category C
