50 questions and answers

What is an Antiseptic?

A chemical used to disinfect living tissue.

What is Antisepsis?

The process of cleaning living tissues of pathogens.

What are the main types of heat used as physical methods of sterilization and disinfection?

Dry heat and moist heat.

Which type of heat is less effective and requires higher temperatures and longer durations?

Dry heat.

Which type of heat is more effective and operates at lower temperatures for shorter times?

Moist heat.

What is an example of a moist heat sterilization method?

Autoclaves using steam.

What type of radiation is highly penetrating, breaks DNA, and is sterilizing?

Ionizing Radiation.

What type of radiation disinfects surfaces but is not reliable for killing endospores?

Nonionizing Radiation.

Name an example of a chemical agent gas that can be sterilizing or disinfecting.

Ethylene oxide.

Name two examples of liquid antiseptics used for animate objects.

Iodines and alcohols.

What is an example of a mechanical agent used to remove microbes physically from air or solutions?

HEPA filters.

What microbial characteristic indicates high resistance to antimicrobial agents?

Endospores.

What microbial characteristics indicate moderate resistance to antimicrobial agents?

Mycobacterium and viruses.

What microbial characteristics indicate low resistance to antimicrobial agents?

Vegetative bacteria and enveloped viruses.

How does microbial load affect the effectiveness of antimicrobial agents?

Higher loads require more time and effort to kill microbes.

Name some types of organic material that can hinder the effectiveness of antimicrobial agents.

Blood, pus, feces, and urine.

How does material type, such as porous surfaces, affect germicide efficacy?

Porous surfaces can absorb agents, limiting efficacy.

Generally, how does germicide concentration relate to effectiveness?

Higher concentration usually leads to better effectiveness.

What is an exception to the rule that higher germicide concentration leads to better effectiveness?

Ethanol, which works better at 70% concentration.

How do higher temperatures generally affect antimicrobial agent effectiveness?

They usually enhance effectiveness.

What is the purpose of the Kirby-Bauer Test?

To determine the effectiveness of antibiotics.

In the Kirby-Bauer Test, what is the 'zone of inhibition'?

The area around the antibiotic disc where microbes cannot grow.

What does a larger zone of inhibition indicate in the Kirby-Bauer Test?

More effective antimicrobials.

What does no inhibition around an antibiotic disc indicate?

The microbe is resistant to that antimicrobial.

What does the Tube Dilution Test measure?

The minimum inhibitory concentration (MIC) required to inhibit growth.

What is the function of the Catalase Test?

It detects the presence of the catalase enzyme that breaks down hydrogen peroxide.

What indicates a positive Catalase Test result?

The presence of bubbles (oxygen gas).

Name an example of a bacterium that tests positive for the Catalase Test.

Staphylococcus aureus.

Name an example of a bacterium that tests negative for the Catalase Test.

Streptococcus species.

What is the purpose of the Coagulase Test?

To further differentiate species of Staphylococcus.

What indicates a positive Coagulase Test result?

The demonstration of clotting when mixed with rabbit plasma.

Name an example of a bacterium that tests positive for the Coagulase Test.

Staphylococcus aureus.

What is the purpose of Capsule Staining?

To identify bacteria with capsules, which evade immune response.

What is a key step to preserve capsule integrity during Capsule Staining?

No heat fixation should be used.

Name two examples of bacteria that test positive for Capsule Staining.

Streptococcus pneumoniae and Klebsiella pneumoniae.

What is the purpose of Spore Staining?

To identify resistant endospores.

What is the primary stain used in Spore Staining?

Malachite green.

What color do endospores appear after Spore Staining?

Green.

What color do vegetative cells appear after Spore Staining?

Red/pink.

Name two genera of bacteria known for producing endospores, identifiable by Spore Staining.

Bacillus and Clostridium species.

What is the purpose of Acid-Fast Staining?

To identify mycobacteria based on mycolic acid in their cell walls.

What is the primary stain used in Acid-Fast Staining?

Carbolfuchsin.

What is the decolorizing agent used in Acid-Fast Staining?

Acid alcohol.

What is the counterstain used in Acid-Fast Staining?

Methylene blue.

What color do acid-fast cells appear after Acid-Fast Staining?

Pink.

What color do non-acid-fast cells appear after Acid-Fast Staining?

Blue.

Name two examples of bacteria that test positive for Acid-Fast Staining.

Mycobacterium tuberculosis and Mycobacterium leprae.

How does moist heat compare to dry heat in terms of effectiveness for sterilization?

Moist heat is more effective than dry heat.

What is a key difference in effectiveness between ionizing and nonionizing radiation?

Ionizing radiation is sterilizing, while nonionizing radiation only disinfects surfaces and isn't reliable for endospores.

Why is it important to differentiate between sterilization, disinfection, and antisepsis?

Each term refers to a different level of microbial control, affecting appropriate application methods and targets (living tissue vs. inanimate objects).