
With antimicrobial resistance (AMR) claiming nearly 5 million lives globally each year—a figure projected to rise by 10% annually until 2030—the World Health Organisation (WHO) has declared it one of the major threats to global public health.
In response to this global health threat, two infectiology specialists at Geneva University Hospitals (Hôpitaux Universitaires de Genève) have developed an open source application aimed at countering antimicrobial resistance by optimising antibiotic usage and enhancing the identification of antimicrobial de-escalation (ADE) events.
A global health threat…
In 2019, it was estimated that AMR was directly responsible for 1.27 millions deaths and contributed to an additional 4.95 millions globally. The death rate associated with AME is primarily explained by the misuse and overuse of antimicrobials, in humans as well as in the broader biosphere. Resulting in the development of “drug-resistant pathogens”, This presents a critical risk to modern medicine as AMR renders a number of infectious diseases harder to treat and increases the risks linked to other medical treatments including cancer.
With the number of global deaths linked to AMR expected to continuously increase in the next few years, countering it has become a key priority for the WHO and world leaders. Demonstrating this is the recent approval of a political declaration on AMR at the 79th United Nations General Assembly, which aims at strengthening global efforts to reduce AMR.
…A scientific challenge…
To counter the effects of AMR, in particular the misuse of antimicrobial drugs including antibiotics, health professionals have developed Antimicrobial Stewardship Programmes (ASPs). These programmes aim to promote a better use of antimicrobial drugs, notably through the prescription of narrow-scope drugs.
Simply, a spectrum of activity refers to the range of microorganisms that can be targeted by the drug, the broader the spectrum the more microorganisms that can be killed or inhibited. This is a critical problem in countering AMR as the misuse, notably overuse, of broad-spectrum antibiotics directly contribute to AMR by impacting a larger range of microorganisms.
The prescription of more targeted, narrow-scope, antibiotics therefore represents a major opportunity to counter AMR. However, assessing antibiotics’ spectra and categorising them has long remained a challenge with little consensus in the scientific community on how to classify spectra.
…An open source solution
To facilitate the assessment and classification of antibiotic spectra, Dr. Mikael de Lorenzi-Tognon, an infectious diseases specialist at Geneva University Hospitals and Postdoctoral Researcher at the University of California San Francisco, alongside Professor Jacques Schrenzel, co-founder of the Centre of Excellence in Bacteriology at the University of Geneva, have launched S³ in April 2024. S³ stands for “Simplified Spectrum Score”.
S³ aims to facilitate antimicrobial / antibiotic de-escalation (ADE) processes. ADE are an element of ASPs by which a narrow-spectrum antibiotic is chosen to replace a broad-spectrum one. However, correctly ranking antibiotics’ spectra to calculate ADE is a complex process requiring manual calculations and is often based on subjective criteria in the weighted spectrum scope.
To facilitate this ranking and calculation processes, S³ is effectively an algorithm allowing the scoring and facilitated classification of antibiotic spectra. Practically this app can be used by health professionals to better target microorganisms when prescribing antibiotics. The app was developed using data from the European Committee on Antimicrobial Susceptibility Testing (EUCAST), covering 63 antibiotics and 837 microorganisms.
As a standardisation testing app, a key benefit of developing S³ as an open source app is to facilitate its access by health professionals in an hospital environment but also beyond, including by public health institutions.
The source code was published on GitHub and the accompanying research paper was published under a Creative Commons licence.
Featured image: National Cancer Institute via Unsplash