Recently, World Antimicrobial Resistance Awareness Week took place. What are we talking about?
Dr Alexandre Charmillon : The problem of resistance does not only concern antibiotics, which target bacteria, but also antivirals which treat viral infections, antiparasitics against parasites, and antifungals used against fungi.
Each of these areas presents more or less significant resistance issues depending on the region of the world. But bacterial resistance is the main concern, particularly due to the massive use of antibiotics all over the planet.
For example, during antibiotic therapy to treat pneumonia, the antibiotic acts not only on the bacteria responsible for the infection, but also on the many others that constitute the patient’s intestinal microbiota.
Certain bacteria, naturally resistant or having acquired resistance, can then proliferate. Hence the increased risk that a future infection will be caused by a resistant strain and will also alter the balance of the microbiota.
What about fungal infections?
The resistance of antifungals is worrying but less so than that of bacteria, because they are rarer. However, certain yeasts such as Candida, notably Candida auris, require particular vigilance worldwide.
This fungus, detected in several countries including France, has the capacity to easily acquire resistance to treatments and to persist in the environment, making its elimination difficult once established, potentially causing hospital epidemics.
Bacterial resistance is acquired but can also be transmitted, like an epidemic?
Indeed, a bacteria can be naturally resistant to an antibiotic or a family of antibiotics. This resistance will be transmitted to its descendants during its multiplication.
But a bacteria can also become resistant to an antibiotic either by mutation or even acquisition of a resistance gene. This consists of the transmission of a resistance gene from one bacterium to another bacterium, sometimes of a different species, via mobile genetic elements such as plasmids (small circular DNA molecule distinct from chromosomal DNA, editor’s note ).
For example, a sensitive Escherichia coli bacteria can acquire resistance to penicillins by coming into contact with another resistant bacteria, Escherichia coli or even Klebsiella pneumoniae, which transfers this resistance gene to it.
On an individual scale, this phenomenon can be observed in everyone, especially if we are regularly exposed to antibiotics. A sensitive bacteria initially present in a patient may become resistant over time.
In the absence of strict hygiene measures, this resistance can spread within hospital services (hands of nursing staff, medical equipment, contaminated surfaces, etc.), leading to epidemics which can go unnoticed if they are not detected.
This is why we speak of a “silent pandemic”. But we are also seeing more and more antibiotic resistance in cities, particularly resistance to E. coli to fluoroquinolone antibiotics.
Since this summer, pharmacists can dispense certain antibiotics in cases of cystitis or tonsillitis, provided that a rapid test is carried out beforehand. Will this reduce the consumption of antibiotics?
This measure is based on the observation of the underuse of these rapid tests, particularly in community medicine. However, they make it possible to distinguish in a few minutes bacterial infections requiring an antibiotic from infections which do not require one, such as viral infections, and therefore promote the proper use of antibiotics.
Another way to reduce antibiotic consumption is to prescribe increasingly shorter antibiotic treatments, supported by solid scientific data. For example, for community-acquired pneumonia, three days of antibiotics may be sufficient in certain conditions, compared to seven days previously.
Better compliance with treatment by the patient, reduction of side effects, lower risk of infections associated with antibiotics such as those caused by Clostridioides difficile*, less risk of emergence of resistance to the antibiotic… There are only benefits!
Similar adjustments were made for other pathologies: in spondylodiscitis (serious bacterial infection of the spine, especially in seniors), the duration was reduced from 12 weeks to 6 weeks.
Although certain situations still justify extended durations, most antibiotic treatments follow this dynamic of duration reduction. Or how to limit the risks of emergence of resistance while guaranteeing clinical effectiveness.
* Certain antibiotics destroy a person’s normal intestinal flora, which allows the development of Clostridioides difficile, which causes diarrhea.
