Contamination and Decontamination Quiz
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Questions and Answers

What is the primary purpose of cleaning before sterilization or disinfection?

  • To remove organic material and reduce microorganisms (correct)
  • To chemically alter the microorganisms
  • To make the surface aesthetically pleasing
  • To enhance the effectiveness of the disinfectants
  • Which sterilization method effectively kills bacterial endospores?

  • Filtration through a membrane
  • Dry heat oven at 160-170 deg C
  • Autoclave at 121 deg C (correct)
  • Boiling at 100 deg C
  • What is the mode of action of phenols in chemical sterilization?

  • Denaturation of enzymes and disruption of plasma membranes (correct)
  • Destruction of microbial DNA
  • Inhibition of protein synthesis
  • Oxidation of cell wall components
  • At what temperature and duration does dry heat sterilization typically occur?

    <p>160-170 deg C for 1-2 hours</p> Signup and view all the answers

    What is the main disadvantage of using phenolics as a sterilizing agent?

    <p>They can cause irritation and have a disagreeable odor</p> Signup and view all the answers

    What is the minimum temperature and time required for effective sterilization in an autoclave?

    <p>121 deg C for 15-20 minutes</p> Signup and view all the answers

    Which method involves passing liquid or gas through a filter to sterilize?

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

    Which of the following methods is NOT considered a physical method of sterilization?

    <p>Chemical disinfection</p> Signup and view all the answers

    What is the term used to describe the process of making something dirty or poisonous?

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

    Which of the following is NOT a form of decontamination?

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

    What level of decontamination eliminates virtually all pathogenic microorganisms except bacterial spores?

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

    Which factor does NOT influence the effectiveness of disinfection?

    <p>Color of the disinfectant</p> Signup and view all the answers

    Which process involves applying a liquid antimicrobial chemical to skin or tissue?

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

    What is the primary purpose of cleaning in a decontamination process?

    <p>To wash away dirt and organic matter</p> Signup and view all the answers

    Which aspect is least likely to affect the level of decontamination achieved on an instrument?

    <p>Type of water used</p> Signup and view all the answers

    What term describes the unintentional introduction of microbial agents into the food chain?

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

    Which mechanism is primarily involved in the action of phenolics on plasma membranes?

    <p>Disruption of membrane integrity</p> Signup and view all the answers

    What is the primary characteristic of triclosan among disinfectants?

    <p>Broad-spectrum antimicrobial activity</p> Signup and view all the answers

    What role does iodine play in antiseptic treatments?

    <p>Inhibits protein function</p> Signup and view all the answers

    How does chlorine function as a disinfectant?

    <p>Alters cellular components</p> Signup and view all the answers

    Which disinfectant is most effective against Gram-positive bacteria?

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

    What is the primary action of alcohols in microbial control?

    <p>Protein denaturation and lipid dissolution</p> Signup and view all the answers

    What is a key drawback of using alcohol as a disinfectant?

    <p>Ineffective against endospores</p> Signup and view all the answers

    What is the primary function of heavy metals in microbial control?

    <p>Denaturation of proteins</p> Signup and view all the answers

    What is the primary mechanism of cationic detergents in microbial control?

    <p>Protein denaturation and membrane disruption</p> Signup and view all the answers

    Which acid is mentioned as effective at controlling molds at low pH levels?

    <p>Benzoic acid</p> Signup and view all the answers

    Which of the following statements about peroxygens is true?

    <p>Ozone can be used as a supplement to chlorination.</p> Signup and view all the answers

    What is the primary purpose of gaseous sterilants such as ethylene oxide?

    <p>To effectively sterilize medical equipment</p> Signup and view all the answers

    Which of the following is NOT a characteristic of acid-anionic detergents?

    <p>High toxicity</p> Signup and view all the answers

    Which component primarily acts through oxidation to exert antimicrobial effects?

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

    What is the function of the plasma membrane in microbial cells?

    <p>Regulation of environmental interaction</p> Signup and view all the answers

    Which of the following antimicrobial agents is categorized as a metabolic inhibitor?

    <p>Ascorbic acid</p> Signup and view all the answers

    What is the primary action of polymyxin B in microbial control?

    <p>Cell membrane disruption</p> Signup and view all the answers

    Which of the following antibiotics specifically inhibits the final step of cell wall biosynthesis?

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

    What type of agents are classified as DNA inhibitors in antimicrobial action?

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

    Which statement accurately describes the mechanism of sulfanilamides?

    <p>They serve as competitive inhibitors of a crucial metabolite.</p> Signup and view all the answers

    Which antimicrobial agent is primarily effective against Gram-positive bacteria?

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

    What is the primary effect of erythromycin on bacterial cells?

    <p>Inhibition of protein synthesis</p> Signup and view all the answers

    What characteristic defines a substance that inhibits nucleic acid synthesis?

    <p>It targets process of DNA and RNA generation.</p> Signup and view all the answers

    Which antibiotic is known for targeting both DNA and RNA synthesis?

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

    Study Notes

    Contamination and Decontamination

    • Contamination refers to the process of making something dirty or toxic, including containing harmful substances.
    • Microbial contamination occurs when harmful microorganisms like bacteria, viruses, or parasites unintentionally enter the food chain and are consumed.
    • Decontamination is the process that makes medical devices, instruments, or surfaces safe to handle and involves sterilization, disinfection, and antisepsis.

    Levels of Decontamination

    • Disinfection: Utilizes liquid chemicals to destroy almost all pathogenic microorganisms except bacterial spores on surfaces and equipment. Effectiveness varies with organism type, organic matter, and exposure conditions.
    • Antisepsis: Involves applying antimicrobial chemicals to living tissues, such as skin, to inhibit or destroy microorganisms. Common in swabbing injection sites and hand washing.
    • Cleaning: Involves using water, detergent, and mechanical actions like scrubbing to remove dirt and reduce microorganisms before further decontamination.
    • Sterilization: Aims to eliminate all microbial life, including resistant bacterial endospores, through physical or chemical means.

    Physical Methods of Sterilization (In Vitro)

    • Radiation: Utilizes short, invisible UV light for germicidal effects, effective against vegetative cells.
    • Burning/Open Flame: Involves heating instruments at 65°C to cause coagulation.
    • Dry Heat Oven: Operates at 160-170°C for 1-2 hours to sterilize instruments like petri dishes.
    • Boiling: Applies temperatures of 100°C or higher to kill vegetative states.
    • Filtration: Involves passing liquids or gases through materials with pores, such as HEPA or membrane filters.
    • Autoclaving: Employs steam under pressure at 121°C for 15-20 minutes to eliminate bacteria and spores.

    Chemical Methods of Sterilization (In Vitro)

    • Phenols & Phenolics: Disrupt plasma membranes and denature enzymes; generally not preferred due to irritating qualities.
    • Bisphenols: Effective as disinfectants in soaps; target a broad spectrum of bacteria.
    • Biguanide (Chlorhexidine): Bactericidal especially against Gram-positive bacteria; used in surgical scrubs.
    • Halogens: Iodine and chlorine serve as strong oxidizing agents for disinfecting water and surfaces.
    • Alcohols: Denature proteins and dissolve lipids; common examples include ethanol and isopropanol.
    • Heavy Metals: Use silver nitrate for microbial denaturation, effective in various applications.
    • Surface-active Agents: Mechanical removal through scrubbing; includes soaps and cationic detergents for broad-spectrum activity.

    Actions of Antimicrobial Drugs

    • Damage to Plasma Membrane: Leads to leakage of cellular contents. Example: Polymyxin B.
    • Inhibition of Cell Wall Synthesis: Protects bacteria from injury; common antibiotics include penicillin and cephalosporins.
    • Inhibition of Protein Synthesis: Disrupts new protein generation; examples are chloramphenicol and erythromycin.
    • Inhibition of Metabolite Synthesis: Compounds that interfere with normal metabolism. Examples include sulfanilamides and trimethoprim.
    • Inhibition of Nucleic Acid Synthesis: Targets DNA and RNA production. Examples are quinolones and rifampicin.

    Specific Antimicrobial Drug Actions

    • Penicillin: Inhibits transpeptidase, essential for cell wall biosynthesis and effective against Gram-positive bacteria.

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    Description

    Test your knowledge on the concepts of contamination and decontamination processes. This quiz covers various aspects including microbial contamination, the significance of sterilization, disinfection, and antisepsis in making surfaces safe to handle. Perfect for students in health sciences or environmental studies.

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