Lecture 8: Control of Microbes Flashcards
What is sterilization?
No living cells, spores, or viruses
Sterilization is a process that eliminates all forms of microbial life.
What is the purpose of disinfectants?
Killing, inhibiting, removing organisms that cause disease, from inanimate objects
Disinfectants are used on surfaces to reduce the risk of infection.
Define sanitization.
Reducing microbial numbers to levels safe for the public
Sanitization is often applied in public health contexts.
What are antiseptics?
Kill or inhibit infection-causing organisms from living tissue
Antiseptics are commonly used in wound care.
What are germicides?
Kill certain organisms, e.g., fungicide, viricide, bactericide
Germicides are used to target specific types of pathogens.
List factors affecting anti-microbial efficiency.
Population size
Population composition Concentration of anti-microbial agent
Length of exposure
Temperature
Local environment
What is a common mistake made while taking antibiotics?
Failure to follow dosage directions
Incorrect dosage can lead to ineffective treatment and resistance.
What is another common mistake made while taking antibiotics?
Failure to finish the course of antibiotics
Not completing the treatment can lead to the selection of resistant bacteria.
What are the five modes of killing by antibiotics?
- Bind to ribosomes, stop translation * Stop cell wall synthesis
- Disrupt membranes
- Stop nucleic acid synthesis
- Inhibit metabolic pathways
Each mode targets a specific aspect of bacterial physiology.
Give an example of an antibiotic that binds to ribosomes.
Streptomycin
Streptomycin is part of the amino glycoside class of antibiotics.
What is a mechanism of bacterial antibiotic resistance involving target modification?
Changes to RNA sequences in the ribosomes
This modification can prevent antibiotics from binding effectively.
What is an example of a drug-altering enzyme produced by bacteria?
Penicillinase
Penicillinase can inactivate penicillin, rendering it ineffective.
What is a method by which bacteria prevent drug entrance?
Efflux pumps
Efflux pumps actively expel antibiotics from bacterial cells.
True or False: Resistant mutants arise spontaneously and are selected for in the presence of antibiotics.
True
This highlights the importance of responsible antibiotic use.
How do bacteria acquire drug resistance?
- Receive resistance genes from other bacteria (horizontal gene transfer)
- Spontaneous, random mutations
These mechanisms contribute to the spread of antibiotic resistance.
When is it appropriate to use antibiotics?
Bladder infections
* Severe sinus infections that last longer than 2 weeks
* Strep throat
* Infections of the skin that get red and swollen (with pus) quickly
Antibiotics should be used judiciously to combat bacterial infections.
Fill in the blank: Anti-fungals and anti-protozoals are difficult to achieve selective toxicity because they are _______.
eukaryotic
Eukaryotic cells share many similarities with human cells, complicating treatment.
What makes anti-virals difficult to achieve selective toxicity?
Obligate intracellular parasites
Footnote Viruses rely heavily on host cell machinery for replication.
