Chapter 13 Microbiology UTA Tholen Verified Answers
Main Goals of Controlling Microbial Growth - Reduce microbial load to minimize infection and contamination.
Definitions of Key Terms - Sterilization: Complete removal and killing of ALL microbes from inanimate objects (fomites) or
organisms....
- Reduce microbial load to minimize infection and contamination.
Definitions of Key Terms
- Sterilization: Complete removal and killing of ALL microbes from inanimate objects (fomites) or
organisms.
- Disinfection: Inactivation or killing of microbes on fomites, not necessarily complete sterilization.
- Sanitization: Decrease of microbial load (the number of microbes) to safe levels.
Biological Safety Levels (BSL)
- Levels of cleanliness assigned to laboratories established by organizations like the CDC, NIH, and WHO.
# BSL-1
- Description: Microbes that pose minimal risk and are not known to cause disease in healthy hosts.
- Features: Sink for handwashing, laboratory doors for containment.
- Example: Non-pathogenic strains of Escherichia coli.
# BSL-2
- Description: Microbes associated with diseases that pose moderate risk.
- Features: BSL-1 features plus personal protective equipment (PPE), self-closing doors, eyewash station,
and autoclave.
- Example: Staphylococcus aureus.
# BSL-3
- Description: Microbes that cause lethal diseases transmitted through respiratory routes.
- Features: BSL-2 features plus respirators, biological safety cabinets, hands-free sinks, and double-door
entrances.
, - Example: Mycobacterium tuberculosis.
# BSL-4
- Description: Dangerous and exotic microbes with high risk of aerosol-transmitted infections, often fatal
without treatment.
- Features: BSL-3 features plus full biohazard suits, showers on exit, and dedicated air supply.
- Example: Ebola and Marburg viruses.
Levels of Cleanliness in Clinical Settings
1. Critical: Must be sterile; items contact sterile tissue (e.g., surgical instruments).
2. Semicritical: Do not require high-level sterilization; items might contact sterile tissue (e.g.,
gastrointestinal scopes).
3. Noncritical: Do not require sterilization; items do not penetrate tissue (e.g., stethoscopes).
Methods of Sterilization and Disinfection
- Sterilization Methods: Heat, pressure, filtration, or chemical agents (sterilants).
- Aseptic Technique: Methods used to prevent contamination of sterile environments.
- Antiseptic: Kills microbes but does not harm the host tissue.
- Disinfectants: Do not kill endospores; examples include hydrogen peroxide and rubbing alcohol.
- Sanitization: Mechanical methods (e.g., hand washing, wiping surfaces) often combined with
disinfectants for effective microbial reduction.
Microbial Control Terminology
- -cides: Agents that kill; examples include bactericidal, virucidal, fungicidal.
- -static: Agents that inhibit growth; examples include bacteriostatic, viristatic, fungistatic.
Concepts Related to Microbial Death
- Microbial Death Curve: A measure of the percentage of microbial kill.
- Decimal Reduction Time (DRT): The time required to kill 90% (1 log reduction) of a microbial
population.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller bestscores1. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $11.12. You're not tied to anything after your purchase.
