Lisa Pagani


Last Name

Pagani

First Name

Lisa

ORCID

0009-0007-5475-9791

Organisational unit

03584 - Bonhoeffer, Sebastian / Bonhoeffer, Sebastian

Filters

2024 - 20252
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Publications 1 - 2 of 2
  • Mutant fate in spatially structured populations on graphs: Connecting models to experiments
    Item type: Journal Article
    Abbara, Alia; Pagani, Lisa; Garcia-Pareja, Celia; et al. (2024)
    PLoS Computational Biology
    In nature, most microbial populations have complex spatial structures that can affect their evolution. Evolutionary graph theory predicts that some spatial structures modelled by placing individuals on the nodes of a graph affect the probability that a mutant will fix. Evolution experiments are beginning to explicitly address the impact of graph structures on mutant fixation. However, the assumptions of evolutionary graph theory differ from the conditions of modern evolution experiments, making the comparison between theory and experiment challenging. Here, we aim to bridge this gap by using our new model of spatially structured populations. This model considers connected subpopulations that lie on the nodes of a graph, and allows asymmetric migrations. It can handle large populations, and explicitly models serial passage events with migrations, thus closely mimicking experimental conditions. We analyze recent experiments in light of this model. We suggest useful parameter regimes for future experiments, and we make quantitative predictions for these experiments. In particular, we propose experiments to directly test our recent prediction that the star graph with asymmetric migrations suppresses natural selection and can accelerate mutant fixation or extinction, compared to a well-mixed population.
  • Decline of antimicrobial resistance in Pseudomonas aeruginosa bacteraemia following the COVID-19 pandemic: a longitudinal observational study
    Item type: Journal Article
    Butscheid, Yulia; Frey, Pascal M.; Pfister, Marc; et al. (2025)
    Journal of Antimicrobial Chemotherapy
    Background: Understanding the effects of changes brought by the COVID-19 pandemic on antimicrobial resistance in P. aeruginosa (PA) is essential to inform clinical management. Methods: This single-centre retrospective cohort study included adult inpatients with PA bacteraemia at the University Hospital Zurich between January 2014 and December 2023. The primary outcome was the association between the start of the COVID-19 pandemic and PA with multidrug resistance (MDR), defined as resistance to $\geq$3 of 5 antibiotic classes. We used logistic regression to adjust for age, sex and ICU treatment. Secondary outcomes included changes in resistance patterns, patient demographics and antimicrobial consumption. Results: A total of 493 instances of PA bacteraemia in 333 patients were observed during the study period. The proportion of MDRPA declined from 21% (62/291) pre-pandemic to 9% (19/202) post-pandemic (adjusted OR 0.38, 95% CI 0.18-0.79, p = 0.01). The occurrence of MDRPA during hospitalization following an initial instance of non-MDRPA bacteraemia was rare and unlikely to happen earlier than after 2 weeks. After the start of the pandemic, we observed no MDRPA cases involving cardiovascular or pulmonary diseases and marked reductions in patients with burn injuries or organ transplants. Furthermore, ciprofloxacin and tobramycin use significantly decreased after the start of the pandemic. Overall in-hospital mortality among patients with MDRPA bacteraemia remained high (28%), with no substantial differences between time periods. Conclusion: We observed a decline in MDRPA occurrence after the start of the COVID-19 pandemic, possibly driven by intensified infection control measures, shifts in antimicrobial use and changes in patient populations.
Publications 1 - 2 of 2