L9 antibiotic resistance

What is antimicrobial resistance?

The ability of an organism to resist the action of an antimicrobial drug

When was penicillin introduced?

1940

By 1959, what percentage of Staphylococcus aureus strains were resistant to penicillin?

95%

Can resistance be natural, acquired, or both?

Both

What does MRSA stand for?

Methicillin

Name one reason for increasing antimicrobial resistance.

Inappropriate use of antibiotics

Give another reason for increasing antimicrobial resistance.

Weak or absent surveillance and monitoring

How does antimicrobial resistance affect healthcare costs?

Increases healthcare costs

What is intrinsic resistance?

Naturally occurring resistance due to normal genetic, structural, or physiological state

What is acquired resistance?

Resistance resulting from altered genetic, structural, or physiological state

Name one way acquired resistance occurs.

Induced genetic mutation after antibiotic pressure

Give another way acquired resistance occurs.

Transfer of genetic material between bacteria

Give an example of intrinsic resistance.

Bacteria without cell walls resistant to penicillin

What is an efflux pump in bacteria?

A pump that exports antibiotics out of the cell

Name an enzyme that inactivates antibiotics.

Beta

How do bacteria evade antibiotics using metabolic pathways?

By using alternative metabolic pathways

How does decreased permeability cause resistance?

Loss of porin channels prevents antibiotic entry

How does biofilm formation contribute to resistance?

Bacteria are covered in polymeric slime and not actively replicating, reducing antibiotic activity

Which bacteria produce beta

lactamases?

How do aminoglycosides like gentamicin face resistance?

Modifying enzymes, reduced uptake, altered ribosomal binding

How do tetracyclines face resistance?

Efflux pumps and reduced uptake

How do quinolones face resistance?

Decreased uptake and altered DNA gyrase binding site

What types of genetic material carry resistance genes?

Chromosomes and plasmids

Name three ways bacteria acquire genes horizontally.

Transduction, conjugation, transformation

Which antibiotic group acts on cell wall by binding PBPs?

Beta

What enzymes do beta

lactams inhibit?

What are ESBLs?

Extended spectrum beta

Name three ESBL

producing organisms.

Which antibiotics can treat ESBL infections?

Carbapenems, cephamycins, fosfomycin, nitrofurantoin, beta

Why has colistin resistance emerged?

Use in agriculture and selective pressure leading to mcr

Name one lab method to detect antibiotic resistance.

Disc diffusion testing

What does e

test measure?

Name one molecular method for detecting resistance.

PCR detection of MecA gene in MRSA

Give one solution to antimicrobial resistance.

Synergistic action of multiple antimicrobials

Give another solution to antimicrobial resistance.

Developing new antimicrobial agents and technologies

Name one aspect of the UK strategy for controlling resistance.

Optimising prescribing practice

Give another aspect of the UK strategy.

Improving infection prevention and control

What is the goal of molecular detection of resistance genes?

Confirm presence of specific resistance genes in pathogens

Why is plasmid

mediated resistance clinically significant?

How does transformation confer resistance?

Uptake of free DNA from the environment

How does conjugation confer resistance?

Transfer of plasmid DNA between bacteria

How does transduction confer resistance?

Bacteriophage transfers resistance genes between bacteria

Why are immunocompromised patients particularly at risk from ESBLs?

Higher vulnerability due to weakened immune system

How can resistance spread globally?

Through community, healthcare settings, and international travel

Why does disruption of commensal microflora increase resistance?

Reduced natural protection leads to increased antibiotic use

What role do beta

lactamase inhibitors play?

Which carbapenems are used for ESBL infections?

Imipenem, meropenem, doripenem

What is the significance of horizontal gene transfer in resistance?

Allows rapid spread of resistance genes across bacterial populations

Why is surveillance important in antimicrobial resistance control?

Detects trends, guides treatment, and informs policy

What is a key outcome of inappropriate antibiotic use in agriculture?

Selective pressure leading to resistance in human pathogens

Which bacterial gene is detected in MRSA PCR testing?

MecA

Name one non

beta

What is the global threat posed by antimicrobial resistance?

Reduced effectiveness of antibiotics, increased mortality, and public health crises

Which laboratory method uses standard zone measurements to assess resistance?

Disc diffusion testing

Which bacteria have plasmid

mediated ESBL genes?

Which environmental factor can contribute to resistance spread?

Antibiotics in water supplies and the environment