iScience (Aug 2024)

Genomic analysis of Staphylococcus aureus isolates from bacteremia reveals genetic features associated with the COVID-19 pandemic

  • Miquel Sánchez-Osuna,
  • Marc Pedrosa,
  • Paula Bierge,
  • Inmaculada Gómez-Sánchez,
  • Marina Alguacil-Guillén,
  • Mateu Espasa,
  • Ivan Erill,
  • Oriol Gasch,
  • Oscar Q. Pich

Journal volume & issue
Vol. 27, no. 8
p. 110402

Abstract

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Summary: Genomic analyses of bacterial isolates are effective to compare the prevalence of antibiotic resistance genes and virulence determinants in different contexts. This study provides a comprehensive genomic description of 339 Staphylococcus aureus strains isolated from patients with bacteremia (2014–2022). Nosocomial acquisition accounted for 56.6% of cases, with vascular catheters being the main infection source (31.8%). Fatality (27.4%), persistent bacteremia (19.5%), and septic emboli (24.2%) were documented. During the COVID-19 pandemic, S. aureus bacteremia episodes increased by 140%. Genetic features in pandemic isolates revealed higher prevalence of methicillin (mecA) and macrolide (msrA and mphC) resistance genes. Additionally, genes encoding clumping factors A and B, involved in fibrinogen binding, were more prevalent. This was linked to extensive macrolide use in COVID-19 accessory therapy and elevated fibrinogen levels in SARS-CoV-2 infection. These findings highlight S. aureus adaptation to COVID-19 selective pressures and the value of whole-genome sequencing in molecular epidemiology studies.

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