(11) Flashcards
a liquid or solid medium with microorganisms growing in or on it
cultures
“sterile” transfer technique is required for virtually all procedures in which living microbes are handled, including isolations, staining, and differential testing; condition of being without contamination
aseptic
federal and private organizations that are responsible for the proper testing, registration, and classification of the substances or systems used to prevent the spread of pathogens; broadly both substances and systems, chemical and physical are germicides
germicides
target a wide variety of pathogens
broad-spectrum
reduction of pathogenic microorganisms to a level at which items are safe to handle without protective attire. Decontamination is the physical removal or cleaning of objects or surfaces and, such as, is the lowest level of pathogen control. It is frequently (but not always) the preparatory work prior to disinfection or sterilization.
decontamination
This level of control (between decontamination and sterilization) is designed to kill all or most targeted vegetative cells, but not spores. All levels employ solid, liquid, or gaseous agents (disinfectants) or inanimate objects or surfaces.
disinfection
high level disinfectants; they have the ability to kill all vegetative cells & spores
chemical sterilants
an actively metabolizing cell
vegetative cells
In bacteria, a dormant form of a microbe protected by specialized coatings produced under conditions of, and resistant to, adverse conditions; also know as an endospore; in fungi and plants, spores are specialized reproductive cells; frequently a means of dissemination.
spores
a disinfectant designed to be used on or in living tissue
antiseptics
highest level of control; complete elimination of viable organisms including spores; can be achieved by many ways such as chemicals, gases, incineration ect…
sterilization
Is hand washing considered decontamination, disinfection, or sterilization?
decontamination
What are the levels of disinfection?
low, medium, and high
What is an example of high-level of disinfection?
chemical sterilants because they have the ability to kill all vegetative cells and spores
What are disinfections used on skin called?
antiseptics
How is sterilization different from disinfection?
sterilization- is the complete elimination of viable organisms including spores
disinfection- designed to kill all or most targeted vegetative cells, but not spores
What are examples of sterilization?
chemicals, gases, incineration
substances designed to reduce the number of pathogens on a surface, liquid, and on or in living tissue
germicides
germicides designed for use on surfaces (floors, tables, sinks, countertops, surgical instruments, ect.) or liquids
disinfection
tests and classifies substances according to their effectiveness against pathogens; used to measure the effectiveness of disinfectants specifically agains Staphylococcus aureus, Salmonella enterica serovar Cholerasuis, and Pseudomonas aeruginosa; glass beads or stainless steel cylinders coated with living bacteria are exposed to varying concentrations (dilutions) of test disinfectants, then transferred to a growth medium; after a period of incubation, the medium is examined for growth; if a solution is sufficient to prevent microbial growth at lease 95% of the time, it meets the required standards and is considered a usable dilution of that disinfectant.
use-dilution test
describes any substance that kills microorganisms, natural or synthetic
antimicrobial
a valuable standard tool for measuring the effectiveness of antimicrobics against pathogenic microorganisms; antimicrobic-impregnated paper disks are placed on a plate inoculated to form a bacterial lawn; the plates are incubated to allow growth of the bacteria and time for the agent to diffuse into agar; as the substance moves through the agar, it establishes a concentration gradient; if the organism is susceptible to the agent, a clear zone will appear around the disk where growth has been inhibited
disk diffusion test
on an agar plate, the area of nongrowth surrounding a paper disc containing an antimicrobial substance
zone of inhibition
the lowest concentration of an antimicrobial substance required to inhibit growth of all microbial cells it contacts; on an agar plate, typically the outer edge of the zone of inhibition where the substance has diffused to the degree that it no longer inhibits growth
minimum inhibitory concentration (MIC)
If you are performing a disk-diffusion test and antibiotic X has a zone of inhibition of 2 cm and antibiotic Y has a zone of inhibition of 4 cm, which one is more effective?
antibiotic Y
What are the 3 groups of UV radiation? What are the wavelengths associated with each group?
UV-A: longest wavelengths; ranging from 315 to 400 nm
UV-B: wavelengths between 280 and 315 nm
UV-C: wavelengths ranging from 100 to 280 nm
Which group is the MOST detrimental to bacterial growth?
UV-C; bacterial exposure to UV-C for more than a few minutes usually results in irreparable DNA damage and death of the organism.
a sterilization chamber that allows the use of steam under pressure to sterilize materials. The most common temperature/pressure combination for an autoclave is 121 C and 15 psi.
autoclave
test systems that contain something living
biological indicator
the dormant form of an organism; are highly resistant to both chemical and physical means of control
bacterial spores
What is the normal sterilizing temperature?
Between 121 C for 15 mins
What is the minimum sterilization time?
Temperature of 134 C for 18 minutes
What organisms are resistant to temperatures >100°C?
Bacillus, Geobacillus and Clostridium
