Exam 2: Ch 13

Question 1

What two factors heavily influence the level of cleanliness required for a particular fomite?

Answer 1

• the type of item: for example, items that require insertion into the human body require a much higher level of cleanliness (surgical tools)
• the level of resistance to antimicrobial treatment by potential pathogens

Question 2

BSL-1

Answer 2

• requires the fewest precautions because it applies to situations with the lowest risk for microbial infection
• agents are those that generally do not cause infection in healthy human adults
• example: non-pathogenic Escherichia coli and Bacillus subtilis
• lab workers use standard aseptic techniques
• wearing PPE, such as lab coat, goggles, and gloves
• may use an autoclave to sterilize equipment

Question 3

BSL-2

Answer 3

• Agents include those that post moderate risk to laboratory workers
• “indigenous”, meaning they are commonly found in that geographical area
• example: Staphylococcus aureus and Salmonella spp., and viruses like hepatitis, mumps, and measles viruses
• additional precautions include restricted access, required PPE, including face, shield, and biological safety cabinets for procedures that may disperse agents through the air
• will also utilize an autoclave to sterilize equipment

Question 4

BSL-3

Answer 4

• agents have the potential to cause lethal infections by inhalation
• agents may be “indigenous” or “exotic”, meaning that they are derived from a foreign location
• example: Mycobacterium tuberculosis, Bacillus anthracis, West Nile virus, and HIV
• workers are under surveillance, receiving vaccinations, must wear respirator
• biological safety cabinet at all times
• must have access to directional airflow, the air cannot be recirculated

Question 5

BSL-4

Answer 5

• Agents are the most dangerous and often fatal
• typically, exotic, are easily transmitted by innovation, and cause infections for which there are no treatment or vaccinations
• example: Ebola virus, Marburg Virus, both causing hemorrhagic fevers and smallpox virus
• workers must change clothes when entering lab, must wear a full body protective suit, shower in exiting
• must conduct all work with any biological safety cabinet with a HEPA filtered air supply

Question 6

Sterilization

Answer 6

the complete removal or killing of all vegetative cells, endospores, and viruses from the targeted item or environment (example surgical tools)

Question 7

Aseptic techniques

Answer 7

involves the combination of protocols that collectively maintain sterility, or sepsis, thus preventing contamination of the patient with microbes and infectious agents

Question 8

Commercial sterilization

Answer 8

a food, sterilization protocol, uses heat at a temperature low enough to preserve food quality, but high enough to destroy common pathogens responsible for food poisoning
* aims for pathogens that spoil food

Question 9

Disinfection

Answer 9

and activates most microbes on the surface of a fomite by using antimicrobial chemicals or heat
* because some of my groups remain, the disinfected item is not considered sterile
* disinfectant should be fast, acting, stable, easy to prepare, inexpensive, and easy to use
* example of a natural disinfectant is vinegar
* example of a chemical disinfectant is chlorine

Question 10

Antiseptics/antisepsis:

Answer 10

antimicrobial chemicals, safe for use on living skin or tissues
* examples: hydrogen peroxide and isopropyl alcohol
* the process of applying an antiseptic is called antisepsis

Question 11

Critical items, semi critical, non critical

Answer 11

• Critical items: must be sterile because it will be used inside the body (surgical items, catheters and intravenous fluids)
• semi critical items: may contact mucous membranes or non-intact skin, but do not penetrate tissues (do not typically need to be sterilized but do require a high level of disinfection)
• non-critical items: items that may contact but not penetrate intact skin (examples are bed, linens, furniture, crutches, stethoscopes, blood pressure cuffs), I need to be clean, but not highly disinfected

Question 12

Degerming

Answer 12

microbial numbers are significantly reduced by gently scrubbing living tissue, mostly skin, with a mild chemical (soap) to avoid transmission of pathogenic, microbes
* examples: handwashing and wiping the skin with an alcohol swab at an injection site
* removes most, but not all microbes from the skins surface

Question 13

Sanitation

Answer 13

cleansing of fomites to remove enough microbes to achieve level steamed safe public health
* commercial dishwashers are an example of sanitation

Question 14

Used in fomites

Answer 14

disinfection, sanitization, and sterilization

Question 15

Used on living tissue

Answer 15

antisepsis and degerming

Question 16

Bactercides

Answer 16

Kill bacteria

Question 17

Viricide

Answer 17

Kill or inactivate viruses

Question 18

Fungicides

Answer 18

Kill fungi

Question 19

Bacteriostatic

Answer 19

Inhibit the growth of bacteria

Question 20

Fungistatic

Answer 20

Inhibit the growth of fungi

Question 21

Common control methods for food preservation

Answer 21

• high temperatures
• radiation
• filtration
• desiccation (drying)

Question 22

Heat

Answer 22

one of the most common and oldest forms of microbial control
* Used in cooking and canning
* boiling is not as effective bc it doesn’t kill all endospores

Question 23

Thermal death point (TDP)

Answer 23

lowest temperature at which all micro groups are killed in a 10 minute exposure

Question 24

Thermal death time (TDT)

Answer 24

length of time needed to kill all microorganisms in a sample at a given temperature

Question 25

Dry heat sterilization

Answer 25

direct application of heat * example: sterilizing inoculating loops and incineration at a very high temperature destroys all microorganisms

Question 26

Moist heat sterilization:

Answer 26

* more effective because in penetrates cells better * uses steam * example: autoclave

Question 27

Autoclaves

Answer 27

* rely on moist heat sterilization * considered the most effective method of sterilization * temp 121*C and 15 psi pressure for 15 minutes

Question 28

Resorts

Answer 28

* similar to autoclaves, but on a much bigger scale * they are like large industrial autoclaves * allows for moist sterilization on a large scale

Question 29

Charles Chamberland

Answer 29

designed the modern autoclave while working in the laboratory of Louis Pasteur

Question 30

What microbe is good for testing autoclaves and the biological indicator spore test?

Answer 30

* Geobacillus Stearothermophilus: resistant to high temperature * a good working autoclave would show no growth of this germ

Question 31

Pasteurization

Answer 31

kills pathogens and reduces the spoilage, causing microbes for maintaining food quality * most commonly used to kill heat sensitive pathogens in milk and other food products

Question 32

Types of pasteurizations:

Answer 32

HTST and UHT

Question 33

High temperature short time pasteurization (HTST):

Answer 33

exposes milk to a temperature of 72°C for 15 seconds, which lowers bacterial numbers while preserving the quality of the milk

Question 34

Ultra high temperature pasteurization (UHT)

Answer 34

milk is exposed to a temperature of 138°C for two or more seconds - UHT pasteurized milk can be stored for a long time and sealed containers without being refrigerated - Can altered proteins in the milk, causing slight changes in the taste and smell

Question 35

Refrigeration

Answer 35

effective method of microbial control with the exception of psychrophiles - refrigerators should be maintained between 0°C and 7°C

Question 36

Safest way to thaw frozen food

Answer 36

inside the refrigerator, immersed in cold water and changed every 30 minutes

Question 37

Pasteurization

Answer 37

heat treatment process used to reduce or eliminate harmful microorganisms in food and beverages without significantly affecting their taste or nutritional value. The process was named after the French scientist Louis Pasteur, who developed it in the 19th century. Purpose: The goal is to kill pathogens (bacteria, yeast, molds) that can cause foodborne illness or spoilage, extending the shelf life of products

Question 38

Filtration

Answer 38

involves physically separating microbes from samples * air is commonly filtered through high efficiency particulate air (HEPA) filters, which removed microbes, endospores, and viruses as air flows through them (used in hospitals) * there’s also membrane filtration, which is used for heat sensitive liquids

Question 39

Phenolics

Answer 39

denature proteins and disrupt the membranes * cresols, o-Phenylphenol, Hexachlorophene, Triclosan * example: disinfectant and Lysol, antibacterial soap

Question 40

Heavy Metals

Answer 40

* considered disinfectants and antiseptics * kill microbes by binding to proteins, thus inhibiting enzymatic activity * heavy metals are oligodynamic, meaning that very small concentration show significant antimicrobial activities * mercury, silver, copper, nickel, and zinc

Question 41

Argyria

Answer 41

skin turns irreversibly blue/grayish due to too much silver accumulating in the body

Question 42

Heavy Metal Murcury

Answer 42

* used to treat scyphus * the use of mercury has diminished because of its toxicity to the central nervous, digestive, and renal systems at high concentrations

Question 43

Heavy metal silver:

Answer 43

* contains a lot of antimicrobial properties * which is why babies are fed with silver spoons

Question 44

Heavy metal copper and zinc:

Answer 44

* copper: control algal growth in swimming pools, combat diarrheal diseases * zinc: found in mouthwashes, calamine lotions, diaper ointments, baby powder, dandruff shampoos

Question 45

Halogens

Answer 45

* oxidation and D stabilization of cellular macromolecules * used for disinfection * includes iodine, chlorine, and fluorine

Question 46

Alcohols

Answer 46

* most effective at 70% concentration * 100% not best because it dries fast * and antiseptic, but also a disinfectant

Question 47

Fomites

Answer 47

Inanimate items, such as doorknobs, toys, or towels, which may harbor microbes and aid in disease transmission

Question 48

Which biosafety level is appropriate for research with microbes or infectious agents that pose moderate risk to workers in the community, and are typically indigenous?

Answer 48

BSL-2

Question 49

HEPA filters and complete body suits are required for which Biological Safety Level?

Answer 49

BSL-4

Question 50

The biosafety level for a clinical microbiology laboratory, working with indigenous and exotic, potentially airborne pathogens, such as tuberculosis bacteria is?

Answer 50

BSL-3

Question 51

an agent used to reduce the number of bacteria on a toilet would most accurately be called?

Answer 51

Disenfectant

Question 52

Which of the following types of medical items require sterilization?

Answer 52

Needles

Question 53

Sanitation leaves an object free of microbes (true or false)?

Answer 53

False

Question 54

Commercial Sterilization kills all microbes (true or false)?

Answer 54

False

Question 55

Complete sterilization kills all microbes (true or false)?

Answer 55

True

Question 56

From a clinical perspective, aseptic technique is carried out to do which of the following?

Answer 56

Prevent contamination in living tissue

Question 57

Which halogen or halogen containing compound is typically used as a form of topical antisepsis?

Answer 57

Iodine

Question 58

Which concentration of ethanol or alcohol is the most effective bactericide?

Answer 58

70%

Question 59

What is the best method to sterilize heat sensitive solutions?

Answer 59

Membrane filtration