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Felipe Francisco Bondan Tuon

Publications and source records attributed to Felipe Francisco Bondan Tuon.

2 recordsLinked to original sources
PubMed2026

Molecular determinants associated with resistance to imipenem and imipenem-relebactam in clinical Pseudomonas aeruginosa isolates.

BACKGROUND: Pseudomonas aeruginosa accounts for 10-20% of hospital-acquired infections and is a major pathogen in immunocompromised patients. Combination therapies with beta-lactam antibiotics and beta-lactamase inhibitors, such as imipenem-relebactam have improved treatment options, yet resistant strains have already emerged, with mechanisms still not fully elucidated. RESULTS: We sequenced and analyzed 10 clinical P. aeruginosa isolates resistant to imipenem-relebactam (IMI/REL) and compared them with publicly available genomes of imipenem-resistant (IMI-R) and imipenem-susceptible (IMI-S) strains. Resistance genes were identified using the RGI CARD database, while amino acid variations in core-genome proteins were evaluated through Gene Ontology overrepresentation analysis (GO), followed by GWAS. In total, 15,758 ARGs were detected, 25.85% associated with carbapenem resistance, but only 568 classified as beta-lactamases. Among IMI/REL isolates, 36.36% carried Ambler class A and 54.54% class B beta-lactamases, contrasting with much lower frequencies in IMI-R (5.4% and 3.6%) and IMI-S (0% and 0.73%). Core-genome analysis revealed 1,106 proteins with resistance-associated variations. Comparative analyzes identified 1,618 proteins differing between IMI/REL and IMI-R genomes, and 1,015 differing between IMI/REL and all other strains. GWAS highlighted candidate genes with strong statistical associations, including those involved in metal ion transport (e.g., tonB, foxA, phuR, pfeA) and efflux pumps (e.g., czcB), as well as regulators such as mexT and biofilm-related proteins. CONCLUSIONS: These findings suggest that, beyond classical beta-lactamases, resistance may be associated with multifactorial contributions from periplasmic and outer membrane proteins, metal ion homeostasis, efflux regulation, and biofilm-associated pathways. Our results expand current knowledge of P. aeruginosa resistome and highlight novel genomic signatures potentially driving resistance to imipenem-relebactam.

Imipenem↗
PubMed2025

Unveiling the Dynamics of SARS-CoV-2 Gamma and Delta Waves in Paraná, Brazil - Delta Displacing a Persistent Gamma Through Alternative Routes of Dispersal.

The Gamma and Delta variants of concern (VOCs) of SARS-CoV-2 drove the second and third wave in Brazil and significantly intensified the number of cases and deaths. In this study, we investigate the timeline and origins of the Gamma and Delta variants using a spatiotemporal analysis based on 1508 genomes collected between March and September 2021 from health administrative regions in Paraná state, Brazil. Our findings indicate that community transmission of Gamma-P.1 began in late 2020, with substantial contributions from the Northeast and North regions. In contrast, our analysis of the Delta-AY.101 genomes underscored the crucial role of Paraná in national-level transmission dynamics beginning in late March 2021. At a local level, the movement estimates inferred from the monophyletic clades showed that the Curitiba health region was the primary source for Gamma-P.1, with a substantial contribution from Londrina. This health-region also emerged as an important hub for Delta-AY.101. Our phylogeographical GLM analysis demonstrates that air travel fluxes and population size at the origin of locations were the strongest predictors of shaping SARS-CoV-2 dispersal dynamics within Paraná. In addition, viral load analysis suggests that Gamma-P.1 and Delta-AY.101 may have maintained a similarly high transmissibility potential throughout the evaluated months, providing insights into the prolonged co-circulation dynamics. Our study underscores the relevance of understanding SARS-CoV-2 introductions and regional circulation contributions at the country level to enhance public health preparedness and strengthen local surveillance programs.

Brazil↗