Antimicrobial resistance (AMR) is a mounting global challenge driven by the misuse of drugs and the rapid adaptability of microbes. As resistant bacteria spread across health systems, agriculture and the environment, the need for informed surveillance and intervention grows urgent.
Conventional treatments are becoming less effective, with some infections now resistant to last-resort antibiotics. This creates higher treatment costs, longer hospital stays and increased mortality. Without intervention, AMR will continue to undermine public health and global development.
This infographic explores the mechanisms by which bacteria evolve resistance, the scale of the global threat and the techniques used to track and combat resistance trends.
Download this infographic to explore:
- How AMR emerges and spreads
- Key resistance mechanisms used by bacteria to evade treatment
- Tools used to detect resistance genes and monitor treatment efficacy
TESTING AND TACKLING
ANTIMICROBIAL RESISTANCE
Written by Kate Robinson | Designed by Danielle Gibbons
Antimicrobial resistance (AMR) involves bacteria, viruses, fungi and parasites changing over
time to become resistant to antimicrobial medicines, threatening the effective prevention and
treatment of a range of infections.
This infographic will explore the mechanisms by which bacteria develop resistance, the growing global
challenge posed by resistant pathogens and the methods used to test antimicrobial effectiveness.
HOW BACTERIA DEVELOP RESISTANCE
Bacteria can develop resistance through two routes: mutation, by which a random DNA change
leads to resistance, or gene transfer, by which resistant bacteria share resistance genes.
THE GLOBAL CHALLENGE OF AMR
Resistance genes allow bacteria to avoid the killing action of antibiotics via the following mechanisms:
Ī Decreased permeability: Outer membrane and metabolite-gating porins decrease the uptake
of antibiotics.
Ī Efflux pumps: Proteins pump antibiotics out of the cell.
Ī Enzymatic degradation: Enzymes are produced to destroy or modify drugs.
Ī Target alterations: The antibiotic target is modified or protected by proteins so the drug can no
longer bind.
Ī Alternative enzymes: Alternative proteins are used instead of the ones targeted by the antibiotic.
Efflux pumps Decreased
permeability
Target alterations
mRNA
Alternative enzymes
DNA
Enzymatic
degradation
A B
Antibiotic Resistance
Horizontal Gene Transfer
Spontaneous mutation
Occurs in the chromosome
Transformation
Free DNA is taken up by the bacterium
Transduction
DNA is transferred from one organism
to another via a bacteriophage,
a virus that infects bacteria
Conjugation
“Mating” that results
in the exchange of DNA
between bacteria
According to the World Health Organization (WHO), AMR is one of the top 10 global
public health threats and an estimated 1.27 million deaths were directly attributed
to AMR in 2019.
While resistance can occur naturally, over- and inappropriate use of antimicrobial drugs in
humans, animals and agriculture is considered a major driver of AMR. These drugs can end up
in our water systems when excreted or by runoff from production sites. A lack of awareness of
proper antimicrobial use, poor waste management and global inequities are also accelerating
the spread of AMR.
According to a 2025 WHO report on global antibiotic resistance, gram-negative bacterial
pathogens pose the greatest threat worldwide, but resistance disproportionately affects lowand
middle-income countries and countries with weak health systems.
The latest bacterial priority pathogens list released by WHO categorizes families of antibioticresistant
pathogens into the following threat levels:
Drug-resistant bacteria are hard to treat and may require the use of antibiotics that come with
serious side effects. For example, fluoroquinolone medicines can cause potentially permanent
side effects including tendon rupture, cognitive issues and impaired hearing, vision, taste and
smell – among others.
Multidrug-resistant bacteria have limited treatment options and higher mortality rates.
Critical High Medium
Enterobacterales
(carbapenem-resistant)
Salmonella Typhi
(fluoroquinolone-resistant)
Group A Streptococci
(macrolide-resistant)
Enterobacterales
(third-generation
cephalosporin-resistant)
Shigella spp.
(fluoroquinolone-resistant)
Streptococcus pneumoniae
(macrolide-resistant)
Acinetobacter baumannii
(carbapenem-resistant)
Enterococcus faecium
(vancomycin-resistant)
Haemophilus influenzae
(ampicillin-resistant)
Mycobacterium tuberculosis
(rifampicin resistant)
Pseudomonas aeruginosa
(carbapenem-resistant)
Group B Streptococci
(penicillin-resistant)
Non-typhoidal Salmonella
(fluoroquinolone-resistant)
Neisseria gonorrhoeae
(third-generation
cephalosporin, and/or
fluoroquinolone-resistant)
Staphylococcus aureus
(methicillin-resistant)
THE GLOBAL CHALLENGE OF AMR
Antimicrobial susceptibility testing is vital in the surveillance of resistance.
Phenotypic methods:
These tests seek to determine the minimum inhibitory concentration (MIC) of the
antibiotic in question. Pre-determined MIC breakpoints allow the bacteria to be classified
as susceptible, intermediate or resistant. The speed and reliability of these methods can
be increased with automated systems.
Disk diffusion: Filter paper disks soaked in known
concentrations of antibiotic agents are placed on
agar inoculated with bacteria. The size of the zone
of inhibition (the area without organism growth
surrounding the disk) is measured to determine the
MIC of the antimicrobial.
Dilution: With broth dilution, consecutive dilutions of
antibiotics are added to a bacterial growth medium.
With agar dilution, antibiotics are diluted into agar,
and bacteria are applied to the plates.
For both methods, the MIC is the lowest concentration
of antibiotic that prevents visible growth.
Gradient diffusion: A combination of diffusion and
dilution, plastic or paper strips coated with varying
antibiotic concentrations are placed on inoculated agar.
The zone of inhibition is used to determine the MIC.
Preventing the spread of AMR requires an approach that combines increasing awareness, good hygiene
practices and responsible antibiotic use. While scientists work to develop new treatments and alternatives,
it is essential to preserve the effectiveness of existing antibiotics and safeguard global health.
m/z
Intensity
Laser
Flight tube
Ionised peptides
Electrostatic
field
Target plate
Detector
In 2023, one in six laboratory-confirmed bacterial infections worldwide were caused
by antibiotic-resistant bacteria.
Molecular methods:
These tests are used to detect mutations and expression of resistance genes.
Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF
MS)- Methods based on MALDI-TOF MS allow for the detection of antibiotic modification
and resistance mechanism proteins.
Quantitative polymerase chain reaction (qPCR): Used
to detect specific resistance genes. Can quantify the
amount of target genomic material present within a
sample without culturing cells.
DNA microarrays: Detect large numbers of resistance
genes simultaneously when they hybridize to a
matching probe on a chip.
