{
  "abstract": "Background/Objectives: Whether the COVID-19 pandemic uniformly increased antimicrobial resistance (AMR) is contested, and aggregate analyses may mask organism-specific patterns. The objective of the study was to characterize changes in the level and slope of monthly multidrug-resistant (MDR), possible extensively drug-resistant (pXDR), possible pandrug-resistant (pPDR), vancomycin-resistant enterococci (VRE), and methicillin-resistant Staphylococcus aureus (MRSA) positivity at a Mexican tertiary-care hospital, and to assess heterogeneity by organism, antimicrobial class, specimen type, and hospital service. Methods: Retrospective interrupted time-series of deduplicated bacterial isolates (October 2017 to January 2026), analyzed by segmented regression across pre-pandemic, pandemic, and post-peak phases. Results: Cohort-wide MDR positivity had been declining before 2020 and rose abruptly at pandemic onset (level shift +6.81 percentage points, p = 0.0092) with a simultaneous slope reversal, reaching 24.27 percentage points above the extrapolated pre-pandemic trend by February 2022 (95% CI 14.26-34.28, p < 0.0001). The decline resumed after the pandemic peak, but the two slope changes did not offset one another (joint p = 0.0064). pXDR and pPDR moved in the same direction (+8.93, p = 0.0233; +15.40, p = 0.0113). VRE showed no significant departure, whereas MRSA declined in every phase yet departed significantly from its extrapolated trajectory (+23.68, p = 0.0040). Among species, Escherichia coli showed the largest departure from its counterfactual (+48.82 percentage points, p < 0.0001) and Klebsiella pneumoniae had the largest abrupt level rise (+14.46 percentage points, p = 0.0055), while S. aureus declined in every phase despite an abrupt rise in level at pandemic onset. At the class level, carbapenem and third-/fourth-generation cephalosporin non-susceptibility rose at pandemic onset and returned to baseline afterwards (19.1% to 28.0% to 18.7%, and 51.7% to 59.4% to 52.5%; all q < 0.001), whereas fluoroquinolone non-susceptibility rose and did not revert, climbing further in E. coli (61.5% to 65.2% to 72.7%, q = 0.0012) and plateauing at an elevated level in K. pneumoniae (37.6% to 46.5% to 49.3%, q = 0.1919 post-peak). Conclusions: Resistance trajectories across pandemic-related phases were divergent and, for the Gram-negative organisms, incompletely reversed, with the highest burden of advanced resistance in high-intensity settings. Organism-resolved surveillance and sustained stewardship are needed.",
  "abstract_shown": true,
  "affiliations": [
    "División de Inmunología, Centro de Investigación Biomédica de Occidente (CIBO), Instituto Mexicano del Seguro Social (IMSS), Sierra Mojada 800, Colonia Independencia, Guadalajara 44340, Jalisco, Mexico.",
    "Programa de Doctorado en Ciencias en Biomédicas, Centro Universitario de Ciencias de la Salud (CUCS), Universidad de Guadalajara, Guadalajara 44340, Jalisco, Mexico.",
    "División de Medicina, Antiguo Hospital Civil de Guadalajara \"Fray Antonio Alcalde\", Calle Hospital 278, Centro Barranquitas, Guadalajara 44280, Jalisco, Mexico.",
    "Urgencias Adultos, Hospital Civil de Guadalajara \"Fray Antonio Alcalde\", Calle Hospital 278, Centro Barranquitas, Guadalajara 44340, Jalisco, Mexico.",
    "Unidad de Investigación Epidemiológica y en Servicios de Salud, Instituto Mexicano del Seguro Social (IMSS), Guadalajara 44340, Jalisco, Mexico.",
    "Laboratorio de Microbiología, Antiguo Hospital Civil de Guadalajara \"Fray Antonio Alcalde\", Calle Hospital 278, Centro Barranquitas, Guadalajara 44280, Jalisco, Mexico.",
    "Departamento de Disciplinas Filosófico, Metodológicas e Instrumentales, Instituto de Investigación de Recursos Humanos en Salud, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara 44340, Jalisco, Mexico.",
    "Departamento de Disciplinas Especializadas I, Decanato de Ciencias de la Salud, Universidad Autónoma de Guadalajara, Av. Patria 1201, Guadalajara 45129, Jalisco, Mexico.",
    "Unidad de Vigilancia Epidemiológica y Medicina Preventiva, Antiguo Hospital Civil de Guadalajara \"Fray Antonio Alcalde\", Calle Hospital 278, Centro Barranquitas, Guadalajara 44280, Jalisco, Mexico."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 12,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Jesús García-Gómez",
      "orcid": "0009-0004-5610-4041"
    },
    {
      "affs": [
        2
      ],
      "name": "Mauricio Alfredo Ambriz-Alarcón"
    },
    {
      "affs": [
        3
      ],
      "name": "Brian Rafael Rubio-Mora",
      "orcid": "0009-0009-2891-924X"
    },
    {
      "affs": [
        0
      ],
      "name": "Luis Felipe Jave-Suárez",
      "orcid": "0000-0001-6209-5031"
    },
    {
      "affs": [
        4
      ],
      "name": "Adriana Aguilar-Lemarroy",
      "orcid": "0000-0001-9288-4824"
    },
    {
      "affs": [
        0
      ],
      "name": "María Martha Villaseñor-García",
      "orcid": "0000-0002-9280-7893"
    },
    {
      "affs": [
        0
      ],
      "name": "Georgina Hernández-Flores"
    },
    {
      "affs": [
        5
      ],
      "name": "María Concepción Rodríguez-Lora"
    },
    {
      "affs": [
        6
      ],
      "name": "Teresita De Jesús Hernández-Flores",
      "orcid": "0000-0002-2849-8635"
    },
    {
      "affs": [
        7
      ],
      "name": "Liliana Iñiguez-Gutiérrez"
    },
    {
      "affs": [
        8
      ],
      "name": "Luis Eduardo Del Moral-Trinidad",
      "orcid": "0000-0002-3218-2019"
    },
    {
      "affs": [
        0,
        5
      ],
      "name": "Anibal Samael Méndez-Clemente",
      "orcid": "0000-0001-8120-896X"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3ggg6phs799es.bib",
  "cited_by": 0,
  "doi": "10.3390/antibiotics15101005",
  "fulltext_url": "https://europepmc.org/articles/PMC13700625",
  "id": "3ggg6phs799es",
  "issns": [
    "2079-6382"
  ],
  "landing_url": "https://europepmc.org/article/MED/42938746",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2402|Antibiotic Use and Resistance"
    ]
  ],
  "openalex": "W7221320914",
  "pdf_url": "https://europepmc.org/articles/PMC13700625?pdf=render",
  "pmcid": "PMC13700625",
  "pmid": "42938746",
  "published": "2026-10-10",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3ggg6phs799es.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:24Z",
      "native_id": "MED:42938746",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42938746"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "openalex:2402|Antibiotic Use and Resistance",
      "subfield": "microbiology"
    }
  ],
  "title": "Divergent Organism-Specific Trajectories of Multidrug Resistance Across the COVID-19 Pandemic: An Interrupted Time-Series Study in a Mexican Tertiary Hospital, 2017-Early 2026.",
  "title_text": "Divergent Organism-Specific Trajectories of Multidrug Resistance Across the COVID-19 Pandemic: An Interrupted Time-Series Study in a Mexican Tertiary Hospital, 2017-Early 2026.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:22:24Z",
  "url": "https://research.draconitic.com/paper/3ggg6phs799es",
  "venue": "Antibiotics (Basel, Switzerland)",
  "versions": []
}