57 Questions
Which method is used to remove nearly all microbes over 0.3 micrometer from air?
High-efficiency particulate air (HEPA) filters
What do germicidal chemicals do?
React irreversibly with proteins, DNA, cytoplasmic membranes, or viral envelopes
Which organization is responsible for ensuring the safety and effectiveness of chemicals used to treat medical devices in the United States?
FDA (Food and Drug Administration)
What are antiseptic rubs used for?
Hand sanitization
What is the main difference between sterilization and disinfection?
Sterilization removes or destroys all microorganisms and viruses, including endospores, while disinfection eliminates most or all pathogens with some viable microbes remaining
What is the purpose of decontamination?
To reduce the number of pathogens to a safe level
What is the main purpose of preservation in the context of controlling microorganisms?
To delay spoilage of perishable products
What is the significance of controlling microbes in healthcare settings?
Weakened patients are more susceptible to infection and may undergo invasive procedures
What is the role of soap in routine control of microorganisms in daily life?
Soap aids in the mechanical removal of organisms
Why is it important for healthcare facilities to protect personnel?
Healthcare facilities must protect personnel as they are at risk of exposure to pathogens
What is the main purpose of pasteurization?
To reduce the number of spoilage organisms and destroy pathogens without changing the characteristics of the product
What distinguishes antiseptics from disinfectants?
Antiseptics are chemicals used on living tissues, while disinfectants are used on inanimate objects
Which type of disinfectant destroys all microbes, including heat-sensitive critical instruments?
Sterilants
What type of disinfectant destroys viruses and vegetative cells, but not reliably endospores?
High-level disinfectants
Which type of disinfectant destroys fungi, vegetative bacteria except mycobacteria, and enveloped viruses, but does not kill endospores or non-enveloped viruses?
Low-level disinfectants
Which of the following is a class of germicidal chemicals?
Aldehydes
Which germicidal chemical is known for its extensive use as an antiseptic with relatively low toxicity?
Biguanides
Which germicidal chemical is a gaseous sterilant for heat- or moisture-sensitive items, but is explosive, toxic, and potentially carcinogenic?
Ethylene oxide
Which class of germicidal chemicals includes chlorine and chlorine dioxide?
Halogens
Which type of compound is extensively used in creams and bandages?
Silver compounds
What replaced silver nitrate eye drops?
Antibiotics
When did the discovery of antimicrobial medications date back to?
Early 20th century
What is the source of most antibiotics?
Microorganisms in the soil
What is the purpose of Generating Antibiotic Incentives Now (GAIN) law?
To encourage new antimicrobial development
What is the difference between bacteriostatic and bactericidal chemicals?
Bacteriostatic chemicals inhibit bacterial growth, while bactericidal chemicals kill bacteria
What is the potential drawback of broad-spectrum antibiotics?
Disrupting the microbiome
What are some adverse effects of antimicrobials?
Allergic reactions, toxic effects, and dysbiosis
What is the role of resistance in antimicrobials?
Intrinsic, acquired, and involve mechanisms targeting specific bacterial processes and structures such as cell wall synthesis
What is selective toxicity in antimicrobial medications?
Interference with essential structures in microbes
How do antimicrobial behaviors differ in the body?
Affecting tissue distribution, metabolism, and excretion
What are some possible interactions of antimicrobial combinations?
Antagonistic, synergistic, or additive
Why is developing new antimicrobial drugs financially risky?
Due to strict and expensive FDA testing
Who purified Streptomycin from the soil bacterium Streptomyces griseus?
Selman Waksman
What does GAIN stand for in the context of antimicrobial development?
Generating Antibiotic Incentives Now
What are Standard Precautions used for in patient care?
To prevent infection of both patients and personnel
In what settings are Transmission-Based Precautions used?
When a patient might be infected with a highly transmissible pathogen
What is the purpose of aseptic technique in microbiology laboratories?
To prevent contamination of samples, workers, and the environment
What factors influence the selection of an antimicrobial procedure?
Type and number of microbes, environmental conditions, and the composition of the item to be treated
Which of the following present challenges for antimicrobial procedures?
Bacterial endospores, protozoan cysts, Mycobacterium species, Pseudomonas species, and non-enveloped viruses
What impacts the time required to sterilize or disinfect a product?
The number of microbes and biofilms
How are medical instruments categorized according to the risk of transmitting infectious agents?
Critical, semicritical, and non-critical items
Why are some sterilization and disinfection methods inappropriate for certain items?
Due to their composition
What is the purpose of autoclaves in microbial control?
To sterilize by raising the steam temperature to kill endospores
What is the purpose of pasteurization and high-temperature–short-time (HTST) methods?
Used in food sterilization
What is extensively used to remove organisms from heat-sensitive fluids in healthcare settings?
Filtration, including membrane filtration
What is the purpose of dry heat, incineration, and hot air ovens in microbial control?
To sterilize and destroy microbes in various settings
Which antibiotic group includes members that are inactivated by extended-spectrum β-lactamases (ESBLs)?
Cephalosporins
Which antibiotic group is generally ineffective against anaerobes, enterococci, and streptococci?
Aminoglycosides
Which antibiotic group is known for being effective against a wide range of Gram-positive and Gram-negative bacteria?
Carbapenems
Which antibiotic group is often considered a last resort against extended-spectrum β-lactamase (ESBL)-producing organisms?
Carbapenems
Which antibiotic group is known for interfering with the transport of peptidoglycan precursors across the membrane, limiting its use to topical applications?
Bacitracin
Which antibiotic group is effective only against Gram-positives and does not cross the outer membrane of Gram-negatives?
Glycopeptide antibiotics
Which antibiotic group is irreversibly bound to the 30S ribosomal subunit, causing it to malfunction and leading to misreading of mRNA by ribosomes past initiation?
Aminoglycosides
Which antibiotic group has members that are generally bacteriostatic and can exploit differences between prokaryotic and eukaryotic ribosomes?
Glycopeptide antibiotics
Which antibiotic group includes members that are from Penicillium chrysogenum and are deactivated by penicillinases?
Penicillins
Which antibiotic group has some members that can produce altered penicillin-binding proteins (PBPs) to which β-lactam antibiotics do not bind well?
Penicillins
Which antibiotic group is grouped by modifications in their side chain and includes penicillinase-resistant members developed in response to penicillinase from S. aureus strains?
Penicillins
Study Notes
Control of Microorganisms in Healthcare Settings
- Standard Precautions are used in patient care to prevent infection of both patients and personnel, while Transmission-Based Precautions are used if a patient might be infected with a highly transmissible pathogen.
- Special care is taken in hospitals and healthcare facilities to control microorganisms in operating rooms, sterilize instruments, and address concerns about prions.
- Microbiology laboratories use rigorous methods of control, including aseptic technique to prevent contamination of samples, workers, and the environment.
- The selection of an antimicrobial procedure is complex and depends on factors such as the type and number of microbes, environmental conditions, and the composition of the item to be treated.
- Multiple highly resistant microbes, including bacterial endospores, protozoan cysts, Mycobacterium species, Pseudomonas species, and non-enveloped viruses, present challenges for antimicrobial procedures.
- The number of microbes and biofilms impact the time required to sterilize or disinfect a product, and environmental conditions such as dirt, grease, body fluids, temperature, and pH influence effectiveness.
- Medical instruments are categorized according to the risk of transmitting infectious agents, with critical, semicritical, and non-critical items requiring different levels of microbial control.
- Some sterilization and disinfection methods are inappropriate for certain items due to their composition, and physical methods such as heat treatment, filtration, irradiation, and high-pressure treatment are used to destroy or remove microorganisms and viruses.
- Moist heat irreversibly denatures proteins, boiling destroys most microorganisms, while pasteurization and high-temperature–short-time (HTST) and ultra-high-temperature (UHT) methods are used in food sterilization.
- Autoclaves use pressurized steam to sterilize by raising the steam temperature to kill endospores, and biological indicators can confirm lack of microbial growth after autoclaving.
- Dry heat, incineration, and hot air ovens are used to sterilize and destroy microbes in microbiology laboratories, medical wastes, and contaminated animal carcasses.
- Filtration, including membrane filtration, is extensively used to remove organisms from heat-sensitive fluids in healthcare settings.
Test your knowledge of controlling microorganisms in healthcare settings with this quiz. Explore topics such as standard precautions, transmission-based precautions, sterilization of instruments, antimicrobial procedures, and methods for controlling highly resistant microbes.
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