[MP LAB] MICROBIAL AND INFECTION CONTROL

Microbial Control

This refers to restricting the growth and normal activities of microorganisms.

Joseph Lister

He was a pioneer of antiseptic surgery and promoted the idea of sterile portable ports.

He was also known as the Father of Modern Surgery.

Phenol

Joseph Lister successfully introduced carbolic acid or now known as ________ to sterilize surgical instruments to clean wounds.

Sterilization

This refers to the removal or destruction of all microbes including viruses and endospores.

False

Sterilization also applies to prions (True or False)

Commercial Sterilization

This is a type of sterilization done in canned food and does not kill all hyperthermophilic microbes.

True

In practical terms, sterilization only eradicates harmful microorganisms and viruses. (True or False)

It is a term describing an environment or procedure that is free of contamination by pathogens

Disinfection

This refers to the use of physical or chemical agents to inhibit or destroy microorganisms especially pathogens.

This is also used only in reference to treatment of inanimate objects.

Disinfectants

These are the physical and chemical agents for disinfection

May include UV light, heat, alcohol, and bleach.

True

Disinfection does not guarantee that all pathogens are eliminated. (True or False)

Antisepsis

When a chemical is used on a skin or other tissue, the process is called _______

Reduction in the number of microorganisms and viruses on living tissue

Antiseptic

These are the chemicals used for antisepsis.

False

Antiseptics are more concentrated than disinfectants and can be left on a surface for longer periods of time. (True or False)

Degerming

This is the removal of microbes from a surface by scrubbing. (Mechanical)

Washing hands or a nurse prepares an area of skin for injection.

This is the process of disinfecting places and utensils used by the public to reduce the number of pathogenic microbes.

Pasteurization

This is the use of heat to kill pathogens and reduce the number of spoilage microorganisms in food and beverages.

True

Words ending in -cide or -cidal refer to agents that destroy or permanently inactivate a particular microbe. (True or False)

Virucides

Inactivates viruses.

Bactericides

Inactivates/kills bacteria.

Fungicides

Kill fungal hyphae, spores, and yeasts.

Germicides

These are chemical agents that destroy pathogenic microorganisms in general.

Cleaning

The removal of visible soil from objects and surfaces accomplished manually or mechanically.

Decontamination

Removes pathogenic microorganisms from objects so they are safe to handle, use or discard.

Microbial Death

This is the permanent loss of reproductive ability under ideal environmental conditions.

Microbial Death Rate

This is usually found to be constant over time for any particular microorganism under a particular set of conditions.

True

The two basic categories on the action of antimicrobial agents include [1] alteration of cell walls and membranes and [2] damage to proteins and nucleic acid. (True or False)

Hypotonic

A cell wall maintains cellular integrity by counteracting the effects of osmosis when the cell is in a ________ solution.

Cytoplasmic Membrane

The _____________ acts as a bag that contains the cytoplasm and controls the passage of chemicals into and out of the cell.

Envelope

In viruses, an __________ is a membrane composed of proteins and phospholipids that is responsible for the attachment of virus to its target cell.

Tolerance

The lack of an envelope in non-enveloped viruses accounts for their greater susceptibility of harsh environmental conditions, including antimicrobial agents. (Modified True or False)

Disulfide Bonds

A protein’s function depends on its exact 3D shape, which is maintained by hydrogen and ___________ between amino acids.

Denatured

__________ proteins cease to function, bringing about cellular death.

Ribozyme

The portion of the ribosome that catalyzes the synthesis of proteins.

An enzymatic RNA molecule.

False

There exists an agent that would control the growth and reproduction of every type of microbe while being harmless to humans, animals, and objects. (True or False)

Site to Be Treated

Relative Susceptibility

Environmental Conditions

Factors Affecting the Efficacy of Antimicrobial Methods

True

Moreover, when performing medical procedures, medical personnel must choose a method and level of microbial control based on the site of the procedure because the site greatly affects the potential for subsequent infection. (True or False)

True

Death rate is usually constant for a particular agent acting against a single microbe. (True or False)

False

Non-enveloped viruses (poliovirus) are more susceptible to antimicrobial agents than enveloped viruses (HIV). (True or False)

Clostridium

Bacillus

Which two common genuses are known to be endospore-bearing?

True

Small non-enveloped viruses are more resistant to antimicrobial drugs than large non-enveloped viruses. (True or False)

Mycobacterium

What genus is known to be acid-fast?

Mycolic Acid

What is the main characteristic of an acid-fast bacteria?

Cyst

A protozoan’s _______ may prevent entry of most disinfectants.

482°C

Temperature (in Celsius) to denature prions.

4 hours

How many hours to denature prions?

High-level

These germicides kill all pathogens, including bacterial endospores.

Intermediate-level

These germicides kill fungal spores, protozoan cysts, viruses, and pathogenic bacteria but not bacterial spores.

Low-level

These germicides eliminate vegetative bacteria, fungi, protozoa, and some viruses.

Used to disinfect furniture and electrodes

True

Warm disinfectants, for example, generally work better than cool ones because chemicals react faster at higher temperatures. (True or False)

Acidic

Basic conditions enhance the antimicrobial effect of heat. (Modified True or False)

BSL-1

This biosafety level is suitable for handling microbes such as E. coli, not known to cause disease in healthy humans

True

Precautions in BSL-1 are minimal and include handwashing with antibacterial soap and disinfecting surfaces. (True or False)

BSL-2

This biosafety level facilities are similar to those of BSL-1 but are designed for handling moderately hazardous agents, such as hepatitis and influenza viruses and methicillin-resistant Staphylococcus aureus.

False

Access to BSL-2 labs is available when work is being conducted; however, extreme precautions are taken with contaminated sharp objects, and procedures that might produce aerosols are conducted within safety cabinets. (True or False)

BSL-3

This biosafety level is stricter, requiring all manipulations be done within safety cabinets containing HEPA filters.

High-Efficiency Particulate Air

What does HEPA mean?

BSL-3 include double sets of doors and lower air pressure in the laboratory, allowing air to move into, not out of the room. (MO

Mycobacterium tuberculosis

Bacillus anthracis

Rickettsia rickettsii

What microbes are being experimented on BSL-3 laboratories?

BSL-4

This is the most secure biosafety level, designated for working with dangerous or exotic microbes that cause severe or fatal diseases (Ebola, smallpox, Lassa fever) in humans.

BSL-4

Entry and exit in BSL-3 are strictly controlled through electronically sealed airlocks with multiple showers, a vacuum room, an ultraviolet light room, and other safety precautions designed to destroy all traces of the biohazard. (Modified True or False)

Heat

This is one of the older and more common means of microbial control.

True

High temperatures denature proteins, interfere with the integrity of cytoplasmic membranes and cell walls, and disrupt the function and structure of nucleic acids. (True or False)

Thermal Death Point

This is the lowest temperature that kills all cells in a broth in 10 minutes.

Thermal Death Point

This is the time it takes to completely sterilize a particular volume of liquid at a set temperature.

False

In comparison to microbial growth, cell death occurs arithmetically. (True or False)

Decimal Reduction Time

This is the time required to destroy 90% of the microbes in a sample.

Clostridium botulinum

Decimal Reduction Time is useful to eliminate the endospores of ___________ which could germinate inside sealed cans.

10⁰ (1)

C. botulinum endospores are reduced to _____.

0.204 minute

What is the D value for C. botulinum endospores? (at 121°C)

Minutes

It would take 2.5 hours to reduce 10¹² C. botulinum endospores to 1. (Modified True or False)

True

Moist heat is more effective in microbial control than dry heat because water is a better conductor of heat than air. (True or False)

Boiling

This moist heat method kills vegetative cells of bacteria and fungi, the trophozoites of protozoa, and most viruses within 10 minutes at sea level.

True

Water at a slow boil is hotter than that of a rapid boil because escaping steam carrier excess heat away. (True or False)

False

At higher elevations, the water also boils at higher temperatures. (True or False)

True

Boiling is not recommended when true sterilization is required. (True or False)

The temperature at which water boils (and steam is formed) increases as pressure increases

Autoclave

This is an equipment that scientists routinely use to sterilize materials that can tolerate moist heat.

This consists of a pressure chamber, pipes to introduce and evacuate steam, and valves to remove air and control pressure.

121°C

What is the desired temperature for autoclaving?

15 psi

What is the desired pressure for autoclaving?

15-20 minutes

What is the desired time for autoclaving?

False

Solid objects must be wrapped in aluminum foil or plastic in autoclaving. (True or False)

Bacillus

A biological indicator of sterility uses endospores of bacteria such as ________ impregnated into tape.

6.9 × 10³ Pascals

SI equivalent of 1 psi is equal to _______

Pasteurization

Brucella melitensis, Mycobacterium bovis, and Escherichia coli are controlled in this heating method.

False

Pasteurization is equal to sterilization. (True or False)

True

Thermoduric and Thermophilic prokaryotes survive pasteurization but do not cause spoilage over the relatively short times, given that it is properly refrigerated. (True or False)

Batch Method

This is the pasteurization method used for milk in which it is pasteurized for 30 minutes at 63°C.

Flash

Most milk processors today use a high-temperature, short-time method known as ________ pasteurization. (72°C for 15 seconds)

1

Ultra High Temperature Pasteurization heats the milk at 135°C for 2 seconds. (Modified True or False)

140°C

Generally, Ultra High Temperature Sterilization involves passing the liquid through superheated steam at about ______ for 1-3 seconds.

The us

True

Hot air is an effective sterilizing agent because it denatures proteins and fosters the oxidation of metabolic and structural chemicals. (True or False)

171°C

What is the temperature needed for dry heat within 1 hour?

160°C

What is the temperature needed for dry heat within 2 hours?

Complete Incineration

This is the ultimate means of sterilization.

0 - 8

Temperature range for refrigeration.

Freezing

These processes decrease microbial metabolism, growth, and reproduction because liquid water is not available at sub-zero temperatures.

This is a freezing process where ice crystals have time to form and puncture cell membranes and is usually more effective than

True

Scientists store many bacteria and viruses in low-temperature freezers at -30°C to -80°C and are able to reconstitute the microbes into viable populations by warming them in media containing proper nutrients. (True or False)