41 Questions
What type of resistance involves chromosomic genetic support, affects almost all species strains, and existed before antibiotic use?
Intrinsic resistance
Which form of antimicrobial resistance affects a fraction of strains and increases with antibiotic use?
Acquired resistance
What is the process by which genetic material is transferred between microbes to cause acquired resistance?
Conjugation
Which of the following is NOT a way in which alteration of the microbial genome occurs?
Transduction
What type of DNA sequences can move or be copied to other regions of the microbial genome?
Transposons
How can mutations arise to cause resistance in a strain?
Spontaneous point mutations
Which form of resistance involves circular 'mini chromosomes' replicating independently of chromosomal DNA?
Plasmidic resistance
'Intrinsic resistance' is characterized by which of the following?
'Existed before antibiotic use.'
How does Clavulanic acid inhibit beta-lactamases?
By causing irreversible acylation of beta-lactamases
What is the purpose of the minimum inhibitory concentration (MIC) test?
To measure the smallest concentration of antibiotic that inhibits the growth of an organism.
What is the main reason for Chloramphenicol resistance?
Acylation by chloramphenicol acetyl transferases (CAT)
What is one method used for the MIC test?
Dilution in liquid broth
Which of the following is a mechanism of resistance exhibited by microbes?
Modifying the drug target
Which process leads to resistance against Aminoglycosides?
Modification like acetylation, phosphorylation, or nucleotide conjugation
What is the mechanism of action of glycopeptides as antibacterials?
Inhibition of bacterial cell membrane synthesis
What type of resistance mechanism involves preventing antimicrobials from entering the microbe?
Antimicrobial exclusion
How does increased methyl groups contribute to drug resistance?
By reducing drug penetration into bacterial cells
Which enzyme is responsible for hydrolyzing the beta-lactam ring in penicillins?
Beta-lactamases
What are the properties of beta-lactamases in gram-positive bacteria?
Inducible and extracellular
How do beta-lactams combat beta-lactamases?
By creating increased steric hindrance
Which aspect describes the mechanism of resistance to glycopeptides in microbes?
Replacement of D-Ala - D-Ala with D-Ala - D-Lac
What is a feature of glycopeptide intrinsic resistance?
Resistance conferred by precursors similar to acquired resistance
How does trimethoprim resistance develop?
Modification of the target enzyme DHFR
What is a characteristic of glycopeptide acquired resistance?
Resistance conferred through the production of 7 new polypeptides
What is the key difference between the lytic and lysogenic cycles of bacteriophages?
The lytic cycle results in the immediate lysis of the host cell, while the lysogenic cycle involves integration of the phage DNA into the bacterial chromosome.
Why do bacteriophages as antibiotics need to be very specific?
To ensure they only target harmful bacteria without affecting beneficial ones.
What contributes to the increase in bacteria resistance to antibiotics?
Overuse and misuse of antibiotics in human and veterinary medicine.
Which mechanism is NOT a common way bacteria develop resistance to antibiotics?
Use of broad-spectrum antibiotics only.
How is antibiotic resistance spread controlled in bacteria?
Proper hand hygiene and sanitation practices.
Which statement accurately describes one way resistance is developed in bacteria?
Resistance can be acquired through horizontal gene transfer from other resistant bacteria.
Which factor is NOT a mechanism of bacterial resistance to antibiotics?
'Good' vs. 'bad' strains within the same species.
What action contributes to reducing antibiotic resistance?
'Rotating' antibiotics - changing them often to prevent resistance buildup.
What impact does prophage excision have on bacterial chromosomes?
It initiates a lytic cycle causing cell lysis.
How does methicillin cause drug target bypass?
By increasing the production of the target enzyme not affected by penicillins.
What does it mean when microbes use enhanced target production to resist drugs?
Microbes increase the production of the drug target.
What is one way that efflux pumps contribute to drug resistance?
By pumping antibiotics out of the cell.
What is one example of drug resistance in fungi?
Resistance to azole antifungals
What is a resistome?
A collection of antimicrobial resistance genes
How can antifolates cause drug target bypass?
By developing an alternative route for folic acid biosynthesis.
What are efflux pumps, where are they located, and what do they require?
Transporter proteins that pump things out of the cell, located in the cytoplasmic membrane, requiring ATP or potential difference for function.
In what way do microbes do a drug target bypass?
By developing alternative mechanisms that side-step key steps in antibiotic action.
Test your knowledge on the two forms of antimicrobial resistance: intrinsic and acquired. Additionally, identify three features of intrinsic resistance such as chromosomal genetic support, affecting almost all species strains, and existing before antibiotic use.
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