{
  "abstract": "Background\n\nMultidrug-resistant (MDR) Serratia marcescens is an important opportunistic pathogen associated with persistent healthcare-associated infections, partly because of its capacity to form biofilms and express virulence-associated factors. Probiotic-derived cell-free supernatants (CFSs) contain secreted metabolites that may provide non-antibiotic approaches for controlling resistant bacteria. However, comparative data on bacterial- and yeast-derived CFSs against S. marcescens remain limited.Methods\n\nCFSs were prepared from Lacticaseibacillus rhamnosus GG, Bacillus coagulans, Bifidobacterium longum, and Saccharomyces boulardii. Metabolite profiles were examined by GC-MS. Antibacterial activity was assessed by disk diffusion and broth microdilution. Biofilm-formation inhibition was evaluated by crystal violet staining at 1/2 and 1/4 MIC. Expression of fimA, bsmA, and shlA was examined by qRT-PCR, and HEK293 cell viability was assessed by MTT.Results\n\nAll four CFSs inhibited S. marcescens growth in a concentration-dependent manner. L. rhamnosus GG showed the greatest activity, with a MIC/MBC of 0.375/0.75 mg/mL and a 26-mm inhibition zone at 12 mg/mL. At 1/2 MIC, biofilm-formation inhibition was 71%, 57%, 47%, and 32%, respectively. All four CFSs significantly reduced fimA and bsmA expression, whereas shlA expression was significantly reduced by L. rhamnosus GG, B. coagulans, and B. longum, but not by S. boulardii. HEK293 cell viability remained above 80% under the tested conditions.Conclusion\n\nProbiotic-derived CFSs demonstrated antibacterial and biofilm-formation inhibitory activities and were associated with reduced expression of selected virulence-associated genes in S. marcescens. L. rhamnosus GG-derived CFSs showed the strongest overall activity, supporting further mechanistic and in vivo studies.",
  "abstract_shown": true,
  "affiliations": [
    "Cellular and Molecular Research Center, Qom University of Medical Sciences, Qom, Iran.",
    "Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.",
    "Department of Laboratory Sciences, Faculty of Paramedicine, Tabriz University of Medical Sciences, Tabriz, Iran."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Mahdi Asghari Ozma",
      "orcid": "0000-0002-4918-8820"
    },
    {
      "affs": [
        1
      ],
      "name": "Niloofar Fallahi Alileh"
    },
    {
      "affs": [
        2
      ],
      "name": "Seyyed Reza Moaddab"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7gqexd74r7gx4.bib",
  "cited_by": 0,
  "doi": "10.2147/idr.s647738",
  "fulltext_url": "https://europepmc.org/articles/PMC13712229",
  "id": "7gqexd74r7gx4",
  "issns": [
    "1178-6973"
  ],
  "landing_url": "https://europepmc.org/article/MED/42948688",
  "language": "eng",
  "licence": "CC-BY-NC",
  "licence_label": "CC BY-NC",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Original Research"
    ],
    [
      "openalex",
      "1312|Bacterial biofilms and quorum sensing"
    ]
  ],
  "openalex": "W7223225750",
  "pdf_url": "https://europepmc.org/articles/PMC13712229?pdf=render",
  "pmcid": "PMC13712229",
  "pmid": "42948688",
  "published": "2026-10-23",
  "publisher": "Dove Press",
  "ris": "https://research.draconitic.com/paper/7gqexd74r7gx4.ris",
  "sources": [
    {
      "first_seen": "2026-10-31T00:20:34Z",
      "native_id": "MED:42948688",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42948688"
    },
    {
      "first_seen": "2026-10-31T12:22:51Z",
      "native_id": "PMC13712229",
      "source": "pmc",
      "url": "https://doi.org/10.2147/idr.s647738"
    }
  ],
  "subjects": [
    {
      "field": "biochemistry",
      "origin": "openalex:1312|Bacterial biofilms and quorum sensing",
      "subfield": "molecular-biology"
    }
  ],
  "title": "Antibacterial Activity, Biofilm Inhibition, and Modulation of Virulence-Associated Gene Expression by Probiotic-Derived Cell-Free Supernatants Against Multidrug-Resistant Serratia marcescens.",
  "title_text": "Antibacterial Activity, Biofilm Inhibition, and Modulation of Virulence-Associated Gene Expression by Probiotic-Derived Cell-Free Supernatants Against Multidrug-Resistant Serratia marcescens.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-31T12:22:51Z",
  "url": "https://research.draconitic.com/paper/7gqexd74r7gx4",
  "venue": "Infection and drug resistance",
  "versions": []
}