Understanding the Impact of Diverse Antibiotics on Gut Bacteria Survival
Author
Libertella, Micael
Term
4. term
Education
Publication year
2025
Submitted on
2025-06-12
Pages
78
Abstract
Den menneskelige tarm rummer en mangfoldig mikrobiota bestående af kommensale bakterier, svampe og virus, som er vigtige for helbredet. Antibiotika kan forstyrre denne balance, hvilket kaldes dysbiose. Traditionelt skelnes der mellem bakteriostatiske antibiotika, som hæmmer vækst, og baktericide antibiotika, som dræber bakterier. Tidligere studier har dog vist, at nogle bakteriostatiske midler kan virke dræbende på bestemte stammer. I dette studie undersøger vi mere detaljeret, hvordan forskellige antibiotika påvirker kommensale tarmbakterier, og om deres virkning er hæmmende eller dræbende afhængigt af den enkelte stamme. Vi anvendte en højkapacitets-tilgang til at måle den minimale hæmmende koncentration (MIC) – den laveste dosis, der forhindrer vækst – for tarmbakteriestammer, hvor sådanne data ikke findes i offentlige databaser. Derefter udførte vi overlevelsesforsøg for at afgøre, om de samme antibiotika faktisk dræbte cellerne eller blot standsede væksten. Vores resultater viser, at flertallet af antibiotika, der tidligere betegnes som bakteriostatiske, udviser baktericide effekter i de undersøgte kommensale stammer. Dette understreger, at antibiotikas virkning kan variere betydeligt mellem stammer, og at selv "statiske" midler kan reducere gavnlige tarmbakterier.
The human gut hosts a diverse microbiota of commensal bacteria, fungi, and viruses that support health. Antibiotics can disrupt this balance, a state known as dysbiosis. Traditionally, antibiotics are described as bacteriostatic when they stop growth and bactericidal when they kill bacteria. However, prior work has shown that some bacteriostatic drugs can kill certain strains. This study takes a closer look at how different antibiotics affect common gut commensal bacteria and whether their actions are growth-inhibiting or killing, depending on the strain. We used a high-throughput approach to measure minimum inhibitory concentration (MIC)—the lowest drug level that prevents growth—for gut bacterial strains lacking published data. We then performed survival assays to test whether the same antibiotics killed cells or merely halted growth. We found that most drugs previously classified as bacteriostatic showed bactericidal effects in the commensal strains tested. These findings highlight that antibiotic effects vary across strains and that even “static” drugs may reduce beneficial gut bacteria.
[This summary has been rewritten with the help of AI based on the project's original abstract]
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