Antimicrobial Resistance: Types and Features

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What is the primary difference between intrinsic and acquired resistance?

The species of microbe involved
The severity of the infection
The type of antibiotic used
The origin of the resistance mechanism (correct)

Which of the following is a characteristic of intrinsic resistance?

It is transferable between microbes
It involves chromosomic genetic support (correct)
It is acquired through antibiotic use
It affects only a fraction of strains

What is the primary mechanism of horizontal evolution in acquired resistance?

DNA repair mechanisms
Gene duplication
Mutations and natural selection
Transfer of genes between microbes (correct)

What is the role of transposons in acquired resistance?

They provide a mechanism for gene transfer (A) Signup and view all the answers

How can genes duplicate to cause resistance in a strain?

Through transposon insertion (C) Signup and view all the answers

What is the result of mistakes in DNA repair in the context of antibiotic resistance?

Mutations that can lead to acquired resistance (B) Signup and view all the answers

What is the primary mechanism of gene transfer in lysogenic bacteriophage infection?

Transduction (B) Signup and view all the answers

Which of the following bacteria is NOT capable of genetically exchanging antimicrobial resistant genes?

Bacillus (A) Signup and view all the answers

What is the purpose of the minimum inhibitory concentration (MIC) test?

To determine the smallest concentration of antibiotic that inhibits the growth of an organism (B) Signup and view all the answers

What is the difference between the liquid media MIC test and the solid media MIC test?

The type of medium used (B) Signup and view all the answers

What is the mechanism of antimicrobial exclusion in gram-negative bacteria?

Preventing the antimicrobial from entering the microbe through the outer membrane (B) Signup and view all the answers

What is the function of beta-lactamases in bacteria?

To hydrolyse the beta-lactam ring (A) Signup and view all the answers

What is the characteristic of beta-lactamases in gram-negative bacteria?

Cell-bound and concentrated in the perisplasmic space (D) Signup and view all the answers

What is the mechanism of action of methicillin in combating beta-lactamases?

Increased steric hindrance (C) Signup and view all the answers

What is the primary mechanism of gene transfer in conjugation?

Transfer of DNA via sexual pilus (A) Signup and view all the answers

What is the purpose of the Kirby-Bauer disc test in the solid media MIC test?

To determine the susceptibility of an organism to an antibiotic (C) Signup and view all the answers

What is the mechanism of action of clavulanic acid in inhibiting beta-lactamases?

It causes irreversible acylation of beta-lactamases. (C) Signup and view all the answers

What is the mechanism of resistance to chloramphenicol?

Acylation of chloramphenicol by chloramphenical acetyl transferases (CAT) (D) Signup and view all the answers

How do glycopeptides inhibit bacterial growth?

By inhibiting peptidoglycan synthesis (D) Signup and view all the answers

What is the mechanism of resistance to glycopeptides in some bacteria?

Modification of the peptidoglycan precursor to reduce glycopeptide binding (A) Signup and view all the answers

What is the mechanism of trimethoprim resistance?

Modification of the dihydrofolate reductase enzyme (C) Signup and view all the answers

What is the mechanism of aminoglycoside resistance?

Modification of the bacterial ribosome (B) Signup and view all the answers

What is meant by drug target bypass?

The use of an alternative pathway that bypasses the target enzyme (A) Signup and view all the answers

How can methicillin resistance lead to drug target bypass?

By producing an additional transpeptidase not susceptible to penicillins (D) Signup and view all the answers

What is meant by enhanced target production as a mechanism of resistance?

The increased production of the target enzyme to overcome antibiotic inhibition (C) Signup and view all the answers

How do sulfonamides contribute to drug target bypass?

By providing an alternative route for folic acid biosynthesis (A) Signup and view all the answers

What is the mechanism of resistance to trimethoprim?

Overproduction of dihydrofolate reductase (D) Signup and view all the answers

What is the location of efflux pumps in bacterial cells?

Cytoplasmic membrane (B) Signup and view all the answers

Which of the following antibiotics is NOT affected by efflux mechanisms?

Penicillin (D) Signup and view all the answers

How do efflux pumps contribute to drug resistance?

By pumping the antibiotic out of the cell (C) Signup and view all the answers

What is the mechanism of resistance to azole anti-fungals in fungi?

Point mutations in the 14alpha-demethylase enzyme gene (C) Signup and view all the answers

What is the resistome?

A collection of antimicrobial resistance genes (D) Signup and view all the answers

What is one advantage of using bacteriophages as antibiotics?

They are natural viruses of bacteria and evolve in parallel to their target (D) Signup and view all the answers

What is the lytic cycle of bacteriophages?

A cycle where the phage reproduces and lyses the host cell (D) Signup and view all the answers

What is a limitation of using bacteriophages as antibiotics?

They need to be very specific to the infecting bacteria, making it hard to achieve (D) Signup and view all the answers

What is the purpose of using multiple antibiotics to combat drug resistance?

To reduce the development of resistance to a single antibiotic (A) Signup and view all the answers