PhD Scientific Days 2026

Poster Session 3.U - Molecular Medicine

Persistent Ciprofloxacin Tolerance is Linked to Altered Baseline Transcription in Mycobacterium Smegmatis

Előadó neve

Döbrőssy, Gergely, MSc

Neptune code

BM9THY

Előadó munkahelye

HUN-REN TTK

Előadó telefonszáma

+36308749775

Előadó e-mail címe

dobrossy.gergely@phd.semmelweis.hu

Az előadás címe

Persistent Ciprofloxacin Tolerance is Linked to Altered Baseline Transcription in Mycobacterium Smegmatis

Szerző(k) neve és munkahelye

Gergely Döbrőssy^1,1, Lilla Fajka^2,3, Angéla Békési^3,4, Dániel Molnár², Beáta G. Vértessy^3,4, Rita Hirmondó⁴, Judit Tóth⁴

1: Molecular Medicine Division, Semmelweis University Doctoral College, Budapest
2: Department of Biochemistry, Eötvös Loránd University, Budapest
3: Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, Budapest
4: Institute of Molecular Life Sciences, HUN-REN Research Centre for Natural Sciences, Budapest

Bemutatás módja

Poszter

Szekció

Poster Session 3.U - Molecular Medicine

Language of the presentation

English

Preferred session

Molecular Medicine

Összefoglaló szövege

Introduction
Tuberculosis (TB), caused primarily by Mycobacterium tuberculosis, remains a major global health threat, and the rise of drug-resistant strains continues to challenge TB control efforts. Our earlier work showed that prolonged antibiotic exposure can induce stable phenotypic tolerance in Mycobacterium smegmatis (Msm) without adaptive mutations, although its molecular basis remains unclear [1].

Aims
This study aimed to characterize the transcriptomic programs associated with ciprofloxacin (CIP)-induced phenotypic tolerance in Msm and to investigate the persistence of this tolerance after growth under antibiotic-free conditions.

Methods
Msm cells were conditioned by prolonged exposure to sublethal CIP, while untreated cells served as controls. For transcriptomic analysis, both groups were sampled under baseline conditions and after acute CIP exposure. We performed exploratory transcriptomic comparisons and functional enrichment analyses on samples from the four experimental conditions. To assess the stability of phenotypic tolerance, minimal inhibitory concentration (MIC) assays were conducted on conditioned and control cells grown under antibiotic-free conditions over time.

Results
Comparison of the four transcriptomic profiles showed that acute CIP exposure triggered similar stress responses, characterized by metabolic downshifts and activation of the DNA damage repair pathway, in both groups. However, conditioned cells showed fewer transcriptional changes in stress-related pathways and broader activation of DNA repair functions. MIC assays confirmed that conditioned cells retained elevated CIP tolerance even after two months in antibiotic-free conditions.

Conclusion
Overall, CIP conditioning altered the baseline transcriptional profile, whereas the response to acute stress remained broadly similar. The lasting increase in drug tolerance indicates a stable physiological state that may be sustained by additional regulatory mechanisms, potentially including epigenetic processes.

References
1. Molnár D et al. (2024) eLife, doi:10.7554/eLife.96695.2

University

Semmelweis University

Supervisor

dr. Judit Tóth, dr. Rita Hirmondó

Publication of my abstract

I give consent to the publication of my abstract on the website of the congress.

phd.section.field

in doctoral studies before complex exam (PhD)

Kind

Szabad

Status

elfogadva

Accepted presentation method

poszter

Előadás fájl jóváhagyás

nem rendelkezett róla

Előadó

9801

Start

14:30

End

14:33