Genomic characterization of a clinical multidrug-resistant Serratia marcescens ST6 isolate from Ecuador
preprint
OA: closed
CC-BY-4.0
Abstract
This study reports the genomic and phenotypic characterization of a multidrug-resistant Serratia marcescens ST6 isolate recovered from a tracheal aspirate in an intensive care unit in Ecuador. Whole-genome sequencing revealed a 5,027,153 bp genome with 59.50% GC content. Antimicrobial susceptibility testing showed resistance to β-lactams, aminoglycosides, and tetracycline, with intermediate susceptibility to meropenem and gentamicin. Resistome analysis identified a limited set of determinants, including the intrinsic genes aac(6′)-Ic, blaSRT, and tet(41). Virulence profiling revealed a complete flagellar and chemotaxis system, iron acquisition systems (enterobactin, aerobactin), a type VI secretion system, biofilm-associated factors (ompA, luxS, rcsB), and stress response regulators (rpoS, phoP). No plasmids or integrons were detected. Phylogenetic analysis placed ST6 within a genetically diverse regional population with no clustering by geography or sequence type, and no evidence of recent clonal expansion. These findings suggest that clinical persistence of this isolate may be supported primarily by chromosomally encoded intrinsic resistance and virulence traits, without usual horizontal gene acquisition. This study highlights the need for continued genomic surveillance of S. marcescens in resource-limited settings.
Full text
1,530 characters
· extracted from
oa-doi-fallback
· click to expand
Full text loading...
Abstract
This study reports the genomic and phenotypic characterization of a multidrug-resistant Serratia marcescens ST6 isolate recovered from a tracheal aspirate in an intensive care unit in Ecuador. Whole-genome sequencing revealed a 5,027,153 bp genome with 59.50% GC content. Antimicrobial susceptibility testing showed resistance to β-lactams, aminoglycosides, and tetracycline, with intermediate susceptibility to meropenem and gentamicin. Resistome analysis identified a limited set of determinants, including the intrinsic genes aac(6′)-Ic, blaSRT, and tet(41). Virulence profiling revealed a complete flagellar and chemotaxis system, iron acquisition systems (enterobactin, aerobactin), a type VI secretion system, biofilm-associated factors (ompA, luxS, rcsB), and stress response regulators (rpoS, phoP). No plasmids or integrons were detected. Phylogenetic analysis placed ST6 within a genetically diverse regional population with no clustering by geography or sequence type, and no evidence of recent clonal expansion. These findings suggest that clinical persistence of this isolate may be supported primarily by chromosomally encoded intrinsic resistance and virulence traits, without usual horizontal gene acquisition. This study highlights the need for continued genomic surveillance of S. marcescens in resource-limited settings.
- Received:
- Version Posted:
Funding
-
Universidad de Especialidades Espíritu Santo
(Award UEES 2026-MED-003)
- Principal Award Recipient: Marco Larrea-Álvarez
Text is read by the "Ask this paper" AI Q&A widget below. Extraction quality varies by source — PMC NXML preserves structure cleanly, OA-HTML may include some navigation residue, and OA-PDF can have broken hyphenation. The publisher copy (via DOI) is the canonical version.
My notes (saved in your browser only)
Ask this paper
Answers must be backed by verbatim quotes from this paper's full text. Hallucinated quotes are dropped automatically; if no verbatim passage answers the question, we say so. How this works
Citation neighborhood (no data yet)
We don't have any in-corpus citations linked to this paper yet. This is a recent paper (2026) — citers typically take a year or two to land, and the OpenAlex reference graph may still be filling in.
Source provenance
- europepmc
- last seen: 2026-05-20T01:45:00.602351+00:00
- unpaywall
- last seen: 2026-05-29T02:00:03.542394+00:00
License: CC-BY-4.0