Fluoroquinolone resistance-associated determinants in ciprofloxacin-susceptible Shigella isolates from Senegal
4 affiliations
- 1Pôle Microbiologie, Institut Pasteur de Dakar
- 2École Doctorale des Sciences de la Vie, de la Santé et de l'Environnement, Université Cheikh Anta Diop de Dakar
- 3Plateforme de Séquençage du Pôle de Virologie, Institut Pasteur de Dakar
- 4Groupe de Recherche Biotechnologies Appliquées and Bioprocédés Environnementaux (GRBA-BE), École Supérieure Polytechnique, Université Cheikh Anta Diop
Abstract
Introduction: Fluoroquinolones remain important therapeutic options for shigellosis, but the accumulation of chromosomal and plasmid-mediated resistance determinants threatens their continued effectiveness. Genomic data on fluoroquinolone resistance-associated determinants in Shigella from West Africa remain limited. Here, we investigated the epidemiological, phenotypic, and genomic characteristics of clinical Shigella isolates recovered through Senegal’s national sentinel surveillance system between 2020 and 2021, with particular emphasis on fluoroquinolone resistance-associated genomic determinants.
Methods: Stool specimens collected from patients with acute diarrhea were cultured for Shigella , followed by antimicrobial susceptibility testing and whole-genome sequencing. Genomes were analyzed for antimicrobial resistance determinants, quinolone resistance-determining region (QRDR) mutations, plasmid replicons, virulence-associated genes, sequence types, and core-genome phylogenetic relationships.
Results: Among 900 diarrheal stool specimens, 22 Shigella isolates were recovered, including 12 S. flexneri , 7 S. sonnei , and 3 S. boydii . All isolates were phenotypically susceptible to ciprofloxacin, whereas qnrS1 was detected in 9/22 isolates (40.9%) and the QRDR substitution gyrA S83L in 4/22 (18.2%). These determinants occurred in non-overlapping isolates, and no gyrA S83V or parC QRDR mutation was detected. IncFII replicons were identified in all isolates, while additional replicons showed heterogeneous distributions across species and sequence types. The fluoroquinolone resistance-associated determinants were distributed across distinct genetic backgrounds rather than being restricted to a single lineage.
Conclusion: These findings demonstrate that phenotypic susceptibility to ciprofloxacin may coexist with fluoroquinolone resistance-associated genomic determinants in clinical Shigella isolates. Integrating WGS with routine antimicrobial susceptibility testing may strengthen surveillance of emerging fluoroquinolone resistance in Shigella in Senegal and West Africa.
Related
- pH-Dependent Evolution of Delafloxacin and Ciprofloxacin Resistance in Pseudomonas aeruginosa from cystic fibrosis (CF) and non-CF-patients
- How do the molecular determinants of antiviral resistance shape the dynamic of phytoplankton-virus interaction?
- Understanding Contemporary Determinants of Antimicrobial Resistance: Towards One Health Literacy and Differentiated Responsibility.
- Whole-genome sequencing-based characterization of antimicrobial resistance determinants and phenotype–genotype concordance in uropathogenic Escherichia coli isolates from ICU patients in Saudi Arabia
- Translation elongation factor EF-P drives susceptibility to fluoroquinolone antibiotics in Bacillus subtilis
BibTeX
@article{lo2026fluoroquinolone,
title = {{Fluoroquinolone resistance-associated determinants in ciprofloxacin-susceptible Shigella isolates from Senegal}},
author = {Cheikh Ibrahima Lo and Elhadj Aly Niang and Ousmane Sadio and Safietou Sankhe and Adja Bousso Guèye and Mouhamed Kane and Marie Odile Ndiaye and Maimouna Mbanne and Jaubert Yelkouni and Sokhna Ndongo and Fatime Poulo Ly and Abdoul Aziz Wane and Cheikh Fall and Moussa Moise Diagne and Yakhya Dieye},
journal = {Frontiers in Microbiology},
year = {2026},
month = oct,
doi = {10.3389/fmicb.2026.1974062},
url = {https://www.frontiersin.org/articles/10.3389/fmicb.2026.1974062/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Fluoroquinolone resistance-associated determinants in ciprofloxacin-susceptible Shigella isolates from Senegal
AU - Cheikh Ibrahima Lo
AU - Elhadj Aly Niang
AU - Ousmane Sadio
AU - Safietou Sankhe
AU - Adja Bousso Guèye
AU - Mouhamed Kane
AU - Marie Odile Ndiaye
AU - Maimouna Mbanne
AU - Jaubert Yelkouni
AU - Sokhna Ndongo
AU - Fatime Poulo Ly
AU - Abdoul Aziz Wane
AU - Cheikh Fall
AU - Moussa Moise Diagne
AU - Yakhya Dieye
PY - 2026
DA - 2026/10/07
JO - Frontiers in Microbiology
DO - 10.3389/fmicb.2026.1974062
UR - https://www.frontiersin.org/articles/10.3389/fmicb.2026.1974062/full
AB - Introduction: Fluoroquinolones remain important therapeutic options for shigellosis, but the accumulation of chromosomal and plasmid-mediated resistance determinants threatens their continued effectiveness. Genomic data on fluoroquinolone resistance-associated determinants in Shigella from West Africa remain limited. Here, we investigated the epidemiological, phenotypic, and genomic characteristics of clinical Shigella isolates recovered through Senegal’s national sentinel surveillance system between 2020 and 2021, with particular emphasis on fluoroquinolone resistance-associated genomic determinants. Methods: Stool specimens collected from patients with acute diarrhea were cultured for Shigella , followed by antimicrobial susceptibility testing and whole-genome sequencing. Genomes were analyzed for antimicrobial resistance determinants, quinolone resistance-determining region (QRDR) mutations, plasmid replicons, virulence-associated genes, sequence types, and core-genome phylogenetic relationships. Results: Among 900 diarrheal stool specimens, 22 Shigella isolates were recovered, including 12 S. flexneri , 7 S. sonnei , and 3 S. boydii . All isolates were phenotypically susceptible to ciprofloxacin, whereas qnrS1 was detected in 9/22 isolates (40.9%) and the QRDR substitution gyrA S83L in 4/22 (18.2%). These determinants occurred in non-overlapping isolates, and no gyrA S83V or parC QRDR mutation was detected. IncFII replicons were identified in all isolates, while additional replicons showed heterogeneous distributions across species and sequence types. The fluoroquinolone resistance-associated determinants were distributed across distinct genetic backgrounds rather than being restricted to a single lineage. Conclusion: These findings demonstrate that phenotypic susceptibility to ciprofloxacin may coexist with fluoroquinolone resistance-associated genomic determinants in clinical Shigella isolates. Integrating WGS with routine antimicrobial susceptibility testing may strengthen surveillance of emerging fluoroquinolone resistance in Shigella in Senegal and West Africa.
SN - 1664-302X
ER -