PART 4

What resistance mechanism involves bacteria producing altered cell wall precursors that prevent vancomycin from binding effectively?

Production of altered cell wall precursors

Which genes are commonly associated with altered cell wall precursors causing glycopeptide resistance in enterococci?

vanA and vanB

How does overproduction of the peptidoglycan (PG) layer contribute to glycopeptide resistance?

It binds excessive amounts of glycopeptide molecules, making the drug ineffective

What is a key difference in the peptidoglycan layer between glycopeptide-susceptible and resistant cells?

Resistant cells have a visibly thicker peptidoglycan layer

How does alteration of the binding site affect glycopeptide antibiotic action?

It prevents effective drug binding, leading to resistance

What enzymatic process causes aminoglycoside resistance by modifying hydroxyl groups through phosphorylation?

Aminoglycoside O-phosphotransferase (APH)

What enzymatic process causes aminoglycoside resistance by adenylation of hydroxyl groups?

Aminoglycoside O-adenyltransferase (ANT)

What enzymatic process causes aminoglycoside resistance by acetylation of amine groups?

Aminoglycoside N-acetyltransferase (AAC)

Name three bacteria species associated with high-level aminoglycoside resistance due to enzymatic degradation.

Enterobacterales, Pseudomonas aeruginosa, Acinetobacter spp.

What type of target alteration leads to aminoglycoside resistance?

Modification of the bacterial 30S ribosomal subunit (aminoglycoside binding site)

How do bacteria reduce intracellular aminoglycoside concentrations to resist the drug?

Decreased uptake pathways or altered uptake mechanisms

What is the overall effect of enzymatic degradation on aminoglycoside antibiotics?

It inactivates the drug, leading to high levels of resistance

What resistance mechanism involves mutations localized to the amino-terminal domains of GyrA and ParC, affecting quinolone binding?

Production of altered target in the quinolone-resistance-determining region (QRDR)

Which subunits of DNA gyrase are involved in quinolone resistance mutations?

gyrA and gyrB subunits

What is the effect of mutations in the QRDR on DNA gyrase function?

DNA gyrase no longer binds quinolones, allowing DNA replication to continue

What resistance mechanism decreases the intracellular concentration of quinolones by actively removing the drug from the cell?

Decreased uptake via efflux pumps

What type of genetic element carries resistance genes that can be transferred between bacteria?

Plasmids

Name a plasmid-borne variant involved in enzymatic inactivation of quinolones.

AAC(6′)-Ib-cr

What is the role of qnr genes in plasmid-mediated quinolone resistance?

They produce proteins that protect DNA gyrase from quinolones

How do plasmid-borne AAC(6’)-Ib variants confer quinolone resistance?

By acetylating fluoroquinolones, reducing their activity

What does PMQR stand for in relation to quinolone resistance?

Plasmid-Mediated Quinolone Resistance

What is the most important mechanism for bacteria to spread antimicrobial resistance?

Lateral Gene Transfer (LGT) or Horizontal Gene Transfer

Name the three physical methods by which DNA is moved during lateral gene transfer.

Conjugation, Transformation, Transduction

What happens to DNA after it is physically transferred during lateral gene transfer?

Incorporation of DNA into the receiving genome

How have clinically relevant bacteria adapted to survive antimicrobial treatment?

By adopting resistance mechanisms encoded on one or more genes

Can resistance genes be shared between different species or genera of bacteria?

Yes, resistance genes are readily shared between strains of the same species, different genera, and distantly related bacteria

What can happen when a single bacterial organism acquires multiple resistance genes?

It can become resistant to the full spectrum of available antimicrobial agents

What does a single potent resistance gene potentially mediate?

Resistance to multiple antimicrobial agents

What is the key action in antimicrobial stewardship to help control antimicrobial resistance?

Guideline-based prescribing and de-escalation

What is the lab scientist’s role in antimicrobial stewardship?

Report susceptibilities and guide therapy

What are the key actions involved in diagnostic stewardship?

Rapid identification and accurate reporting

What is the lab scientist’s role in diagnostic stewardship?

Maintain rapid tests and interpret resistance

What are the key infection prevention and control measures to prevent antimicrobial resistance?

Hand hygiene, isolation, and environmental cleaning

How does the lab scientist contribute to infection prevention and control?

Screen for multidrug-resistant organisms (MDROs) and inform control measures

What actions are involved in surveillance and reporting of antimicrobial resistance?

Cumulative antibiograms and data sharing

What is the lab scientist’s role in surveillance and reporting?

Analyze and submit antimicrobial resistance data

What are key education and awareness strategies to combat antimicrobial resistance?

Provider training and patient education

What role do lab scientists play in education and awareness?

Lead in-service training and public outreach

What are the key research and regulation actions to control antimicrobial resistance?

New drug development and policy advocacy

How do lab scientists support research and regulation efforts?

Validate new assays and support clinical trials