Microbial Control Methods

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Cooking utensils are often __ when used in restaurants.

sanitized

Dry heat is more effective at killing microbes than moist heat.

False (B)

Which of the following is NOT a physical agent used to control microbes?

  • filtration
  • boiling water
  • ethylene oxide (correct)
  • pasteurization
  • radiation

100% Ethanol solutions are more effective antimicrobial agents than are 70% solutions.

<p>False (B)</p> Signup and view all the answers

Alcohol sterilizes skin.

<p>True (A)</p> Signup and view all the answers

Nonionizing radiation such as __ kills bacteria by __.

<p>UV: including mutations in DNA</p> Signup and view all the answers

Household bleach is used as a common disinfectant because it has __.

<p>hypochlorite</p> Signup and view all the answers

Placing objects in boiling water __ them.

<p>disinfects</p> Signup and view all the answers

Which of the following has the HIGHEST resistance to killing?

<p>bacterial endospores (A)</p> Signup and view all the answers

A chemiclave sterilizes objects by exposing them to __ gases.

<p>formaldehyde</p> Signup and view all the answers

An autoclave sterilizes objects by using __.

<p>steam under pressure</p> Signup and view all the answers

Chemical surfactants kill microbes by __.

<p>disrupting membranes</p> Signup and view all the answers

A viricidal agent will __.

<p>kill viruses</p> Signup and view all the answers

Treatment with cold __ microbial growth.

<p>slows</p> Signup and view all the answers

If you had a nonautoclave safe object that you needed to use as a surgical implant, how would you clean it for use? (Select all that apply)

<p>antisepsis (A), vaporized hydrogen peroxide (B), plasma sterilization (C)</p> Signup and view all the answers

What are the advantages of antisepsis? (Select all that apply)

<p>compatibility (A), penetration (B), effectiveness (D)</p> Signup and view all the answers

What are the advantages of vaporized hydrogen peroxide sterilization? (Select all that apply)

<p>less toxic than ETO (B), shorter time used on materials sensitive to high temps (D), penetrating power (E)</p> Signup and view all the answers

What are the advantages of plasma sterilization? (Select all that apply)

<p>various materials (C), quick (D), low temp process (E)</p> Signup and view all the answers

Which of the following are characteristics of moist heat? (Select all that apply)

<p>physical (A), denatures proteins (B), autoclave (C)</p> Signup and view all the answers

Which of the following are characteristics of ethylene oxide? (Select all that apply)

<p>chemiclave (A), damages DNA, RNA, and proteins (B), chemical (C)</p> Signup and view all the answers

Which of the following are characteristics of pasteurization? (Select all that apply)

<p>denatures proteins (A), physical (B), pasteurizing milk (C)</p> Signup and view all the answers

Which of the following are characteristics of halogenation? (Select all that apply)

<p>disrupts S bonds (A), chemical (B), antibiotics (vancomycin, chloramphenicol) (C)</p> Signup and view all the answers

Which of the following are characteristics of filtration? (Select all that apply)

<p>isolating or separating organisms (A), HEPA filters (B), mechanical (C)</p> Signup and view all the answers

Which of the following are characteristics of ionizing radiation? (Select all that apply)

<p>breaks DNA (A), physical (B), irradiation of mail (C)</p> Signup and view all the answers

Which of the following are characteristics of surfactants? (Select all that apply)

<p>cell membrane (A), chemical (B), rubbing alcohol (C)</p> Signup and view all the answers

Which of the following are characteristics of hydrogen peroxide? (Select all that apply)

<p>chemical (A), oxidizes proteins (B), antiseptic use (C)</p> Signup and view all the answers

Which of the following are characteristics of quaternary ammonia compounds? (Select all that apply)

<p>chemical (A), detergent (B), shampoos, hand soaps, disinfectant sprays (C)</p> Signup and view all the answers

Which of the following are characteristics of heavy metals? (Select all that apply)

<p>thimerosal (A), proteins and enzymes (B), chemical (C)</p> Signup and view all the answers

Which of the following are characteristics of Aldehydes? (Select all that apply)

<p>cidex (A), chemical (B), cross-link proteins (C)</p> Signup and view all the answers

Which of the following are characteristics of sanitizing? (Select all that apply)

<p>pathogens (A), mopping, dishwasher (B), mechanical (C)</p> Signup and view all the answers

Which of the following are characteristics of cold temperatures? (Select all that apply)

<p>refrigeration (A), cell membrane (B), physical (C)</p> Signup and view all the answers

Which of the following are characteristics of phenolics? (Select all that apply)

<p>protein denaturant (A), chemical (B), triclosan (soap) (C)</p> Signup and view all the answers

Unwanted organisms in a culture are called __.

<p>contaminants</p> Signup and view all the answers

Which of the following are examples of contaminants? (Select all that apply)

<p>poison air (A), pollute (B), soil (C), water (D), food (E)</p> Signup and view all the answers

What are the three methods used in decontamination protocols? (Select all that apply)

<p>disinfection (B), antisepsis (C), sterilization (D)</p> Signup and view all the answers

What is the difference between physical and chemical methods of microbial control?

<p>Physical methods use physical forces to control microbes, such as heat, radiation, or pressure, whereas chemical methods use chemical reactions.</p> Signup and view all the answers

Are all contaminants equally susceptible to physical and chemical means of decontamination?

<p>False (B)</p> Signup and view all the answers

How do sterilization and disinfection differ?

<p>A sterile object has no living cells, spores, or viruses, while a disinfected object may still have a small number of these.</p> Signup and view all the answers

Can something be almost sterile?

<p>False (B)</p> Signup and view all the answers

What is the difference between a -cidal agent and a -static agent?

<p>-cidal agents kill microorganisms, while -static agents only inhibit their growth and reproduction.</p> Signup and view all the answers

If you take bacteriostatic antibiotics for an infection, what will happen when you stop taking the antibiotic?

<p>Stopping bacteriostatic antibiotics too soon can allow the infection to reoccur and may contribute to antibiotic resistance.</p> Signup and view all the answers

Disinfectants are used on __ surfaces.

<p>inanimate</p> Signup and view all the answers

Antiseptics are used on __.

<p>body</p> Signup and view all the answers

Which of the following are examples of disinfectants? (Select all that apply)

<p>bleach (A), alcohol (D), hydrogen peroxide (E)</p> Signup and view all the answers

Which of the following are examples of antiseptics? (Select all that apply)

<p>antibacterial soap (A), mouthwash (B), antimicrobial cleaner (C), hydrogen peroxide (E)</p> Signup and view all the answers

Your bathroom in a public restroom may say "sanitized for your protection". Is sanitization the same as sterilization?

<p>False (B)</p> Signup and view all the answers

When is a microbe considered dead?

<p>When it has permanently lost its ability to reproduce under ideal conditions.</p> Signup and view all the answers

How do the number of organisms and their state of growth (spores vs. vegetative cells) affect microbial death rate?

<p>A larger population takes longer to completely eliminate due to the logarithmic nature of microbial death, with spores generally being much more resistant, leading to a slower death rate compared to vegetative cells.</p> Signup and view all the answers

How does a chemical agent's concentration affect microbial death rate?

<p>Higher concentrations generally lead to a faster rate of microbial killing.</p> Signup and view all the answers

What are the four major cellular targets for antimicrobial agents? (Select all that apply)

<p>protein synthesis (ribosomes) (B), cell wall (C), nucleic acid synthesis (DNA) (D), cell membrane (E)</p> Signup and view all the answers

Name one agent that targets bacterial cell walls.

<p>penicillin (A), cephalexin (B), vancomycin (C)</p> Signup and view all the answers

How do surfactants work?

<p>Surfactants interfere with and break up the cell membrane components such as lipids and proteins.</p> Signup and view all the answers

How may proteins be denatured?

<p>Proteins can be denatured by heat, chemicals, or pH extremes. This process disrupts the 2nd,  3rd and 4th structure of proteins, causing them to lose their function. The loss of structure and function can lead to the death of the cell.</p> Signup and view all the answers

How does heat affect microbial cells?

<p>Heat denatures their proteins and disrupts their cell membranes, which can lead to cell death at high temperatures.</p> Signup and view all the answers

Moist heat is more effective than __ heat.

<p>dry</p> Signup and view all the answers

If organism A has a TDT of 15 minutes and organism B has a TDT of 35 minutes, using the same temperature, which organism is most resistant to heat?

<p>organism B (B)</p> Signup and view all the answers

Why is pressure added to the stream present in an autoclave?

<p>Pressure in an autoclave serves to increase the temperature and efficiency of sterilization, prevent evaporation, and enable the process to occur faster and more effectively.</p> Signup and view all the answers

What is tyndallization?

<p>Tyndallization is a method of sterilization that involves intermittent boiling with periods of cooling to destroy both vegetative cells and endospores over multiple cycles.</p> Signup and view all the answers

Does boiling water sterilize the water?

<p>False (B)</p> Signup and view all the answers

Does pasteurization sterilize milk?

<p>False (B)</p> Signup and view all the answers

What does pasteurization of milk do?

<p>Pasteurization kills harmful bacteria in milk, making it safe to drink and increasing its shelf life.</p> Signup and view all the answers

Why is cold not used to kill microbes?

<p>Cold temperatures primarily only slow down or inhibit their growth, not outright destroy them.</p> Signup and view all the answers

Why does radiation limit microbe growth?

<p>Radiation can damage the DNA of microorganisms, disrupting their ability to replicate and causing cell death.</p> Signup and view all the answers

What is ionizing radiation?

<p>Ionizing radiation is a type of high-energy radiation that has enough power to remove electrons from atoms within a cell, creating ions and potentially causing significant damage to DNA, leading to cell death.</p> Signup and view all the answers

How is the usefulness of nonionizing radiation limited?

<p>The usefulness of nonionizing radiation is limited by its penetration power, resistance of certain microorganisms, dose requirements, safety concerns, and environmental interference.</p> Signup and view all the answers

When is filtration an effective method to remove contaminants?

<p>Filtration is effective when removing contaminants that are large, suspended, or when a high level of purity is required.</p> Signup and view all the answers

How do aqueous solutions differ from tinctures?

<p>Aqueous solutions are water-based, while tinctures are alcohol-based.</p> Signup and view all the answers

Describe several characteristics that the ideal chemical antimicrobial agent would have.

<p>The ideal chemical antimicrobial agent would have broad-spectrum activity against a variety of microbes while maintaining selective toxicity towards pathogens, high potency at low concentrations, rapid action, stability in different environments, minimal resistance development potential, low toxicity to host tissues, good solubility in body fluids, reasonable cost, and a manageable half-life allowing for appropriate dosing intervals.</p> Signup and view all the answers

How does bleach work as a disinfectant?

<p>Bleach works as a disinfectant by denaturing proteins in microorganisms, which kills bacteria, viruses, and fungi.</p> Signup and view all the answers

How does alcohol kill bacteria?

<p>Alcohol kills bacteria through a process called denaturation, which breaks down the proteins in the structure of germs.</p> Signup and view all the answers

What is the cellular target of detergents?

<p>The cellular target of detergents is the cell membrane.</p> Signup and view all the answers

What are the cellular targets of heavy metals?

<p>Heavy metals can target various cellular components, including proteins, DNA, cell membranes, mitochondria, and enzymes.</p> Signup and view all the answers

Glutaraldehyde is used to sterilize contaminated areas--how does it kill microbes?

<p>Glutaraldehyde kills microbes by cross-linking proteins and nucleic acids, disrupting cell membranes, and preventing the microbe from replicating, making it a powerful and broad-spectrum sterilizing agent.</p> Signup and view all the answers

Ethylene oxide is a sterilant. Why is it not used on human tissues?

<p>Ethylene oxide is a known human carcinogen, meaning it can directly cause cancer in humans, due to its ability to damage DNA.</p> Signup and view all the answers

Flashcards

Cooking utensils, sanitization

Cleaning of utensils to remove harmful microorganisms.

Dry heat vs. Moist heat

Dry heat is less effective than moist heat at killing microbes.

Physical agent vs. Ethylene oxide

Ethylene oxide is a chemical agent, not a physical one.

100% Ethanol vs. 70% Ethanol

70% ethanol is more effective as an antimicrobial agent.

Signup and view all the flashcards

Alcohol sterilizing skin

Alcohol can sterilize skin if used correctly.

Signup and view all the flashcards

UV radiation and microbes

UV radiation damages DNA in microbes.

Signup and view all the flashcards

Household bleach and disinfectant

Bleach is a common disinfectant due to hypochlorite.

Signup and view all the flashcards

Boiling water and disinfection

Boiling water disinfects objects.

Signup and view all the flashcards

Bacterial endospores resistance

Bacterial endospores are highly resistant to killing.

Signup and view all the flashcards

Chemical agents, Formaldehyde, and sterilization.

Formaldehyde is a chemical agent used in chemical vapor sterilizations.

Signup and view all the flashcards

Chemical agents vs. Filtration

Filtration is a physical method, not a chemical one.

Signup and view all the flashcards

Autoclave, Sterilization

Autoclaves use steam under pressure for sterilization.

Signup and view all the flashcards

Surfactants and microbes.

Surfactants disrupt cell membranes.

Signup and view all the flashcards

Viricidal agent function

Viricidal agents kill viruses.

Signup and view all the flashcards

cold treatment effect

Cold temperatures slow microbial growth.

Signup and view all the flashcards

Non-autoclave, surgical implant cleaning

Methods for cleaning objects for surgical implants include antisepsis, vaporized hydrogen peroxide, and plasma sterilization.

Signup and view all the flashcards

Antisepsis pros

Effective, compatible with materials, and penetrates well.

Signup and view all the flashcards

Vaporized hydrogen peroxide pros

Less toxic than ethylene oxide and shorter time is best for materials sensitive to heat.

Signup and view all the flashcards

Plasma sterilization pros

Low temperature process, various materials, and quick.

Signup and view all the flashcards

Moist heat method

Denatures proteins, and works with steam at pressure.

Signup and view all the flashcards

Study Notes

Microbial Control Methods

  • Sanitization: Reduces microorganisms to safe public health levels. Often used on cooking utensils.

  • Dry Heat vs. Moist Heat: Dry heat is not more effective at killing microbes than moist heat.

  • Physical Agents: Ethylene oxide is not a physical method to control microbes. Physical methods include heat, radiation, and filtration.

  • Alcohol Effectiveness: 70% ethanol solutions are more effective antimicrobial agents than 100%.

  • Alcohol's Role: Alcohol can sterilize skin.

  • UV Radiation: Nonionizing radiation like UV light kills microbes by causing mutations in DNA.

  • Bleach as Disinfectant: Household bleach's disinfecting power comes from its hypochlorite content.

  • Boiling Water: Boiling water disinfects objects.

  • Endospore Resistance: Bacterial endospores have the highest resistance to killing methods compared to other microbial forms.

  • Chemical Sterilization: A chemiclave uses formaldehyde gas for sterilization.

  • Chemical vs. Physical Control: Filtration is a physical method, not a chemical one. Chemical agents directly affect microbial cells, while physical agents often alter the environment to kill or inhibit.

  • Autoclave: An autoclave sterilizes using steam under pressure.

  • Surfactant Mechanism: Chemical surfactants kill by disrupting cell membranes.

  • Viricidal Agents: Viricidal agents kill viruses.

  • Cold Temperatures: Cold temperatures slow microbial growth.

  • Decontamination Protocols: The three methods are sterilization, disinfection, and antisepsis.

  • Sterilization vs. Disinfection: Sterilization eliminates all living microorganisms, whereas disinfection reduces them to safe public health levels.

  • Sterile vs. Almost Sterile: 100% sterility is unattainable, and the concept of 'almost sterile' exists.

  • -Cidal vs. -Static: -Cidal agents kill microbes, while -static agents inhibit their growth.

  • Antibiotic Usage: Stopping bacteriostatic antibiotics too soon can allow the infection to return and potentially lead to antibiotic resistance.

  • Disinfectant vs. Antiseptic: Disinfectants are used on inanimate objects, and antiseptics on living tissue.

  • Types of Microbial Death: A microbe is considered dead when it permanently loses reproductive ability under ideal conditions.

  • Death Rate Factors: Microbial death rate depends on population size, growth state (e.g., spores vs. vegetative cells), and agent concentration.

  • Cellular Targets: Key targets for antimicrobial agents are cell walls, cell membranes, proteins, and nucleic acids.

  • Microbial Death Mechanisms: Various mechanisms exist, from disrupting structures to altering protein or DNA function.

  • Heat's Effect: Heat affects microbial cells through protein denaturation and membrane disruption.

  • Moist vs. Dry Heat: Moist heat is generally more effective than dry heat in microbial killing.

  • TDT (Thermal Death Time): Lower TDT values indicate greater sensitivity to heat.

  • Autoclave Principle: Pressure in autoclaves increases temperature and sterilization efficiency.

  • Tyndallization: A method of sterilization that targets both vegetative cells and endospores in intermittent boiling cycles.

  • Pasteurization: Pasteurization does not sterilize, merely reduces microbial load in foods and liquids.

  • Cold's Effect: Cold slows microbial growth, preventing their cell development but not necessarily their death.

  • Radiation Effects: Ionizing radiation damages DNA, limiting microbial growth through cell destruction or mutations. Nonionizing radiation also limits microbe growth.

  • Filter Effectiveness: Filtration effectively removes pathogens from air or liquids, particularly with large or suspended organisms.

  • Solution Types: Aqueous solutions are water-based, while tinctures are alcohol-based.

  • Ideal Chemical Antimicrobial Agent: Characteristics include broad spectrum, selective toxicity, rapid action, and stability.

  • Bleach Action: Bleach's disinfectant effect is due to protein denaturation.

  • Alcohol Action: Alcohol denatures proteins, killing bacteria.

  • Detergent Target: Detergents act on cell membranes.

  • Heavy Metals: Heavy metals affect proteins, DNA, cell membranes, mitochondria, and enzymes.

  • Glutaraldehyde: Glutaraldehyde crosslinks proteins and nucleic acids to destroy microbes.

  • Ethylene Oxide: Ethylene oxide is a potent sterilant but is a known carcinogen and thus, not used on human tissues.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser