Universidad del Desarrollo

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Geographic divergence of methicillin-resistant Staphylococcus aureus ST5-SCCmecI in the aftermath of a major earthquake and tsunami: impact of a plasmid harboring heavy metal resistance genes
(American Society for Microbiology, 2025-04-09)
Jose R. W. Martínez
;
Manuel Alcalde-Rico
;
Estefanía Jara-Videla
;
Jinnethe Reyes
;
Lina P. Carvajal
(MRSA) is a major public health menace. The global spread of MRSA is characterized by successive waves of epidemic clones dominating specific geographical regions. The acquisition of genes encoding resistance to heavy metals (HMRGs) is thought to be a key feature in the geographic divergence of MRSA. However, the cause-effect relationship between the presence of HMRGs and the divergence of MRSA clones remains to be clarified. In this study, we assessed the role that HMRGs may have played in the evolutionary divergence of the MRSA ST5-SCC <jats:italic>mec</jats:italic> I lineage in Latin America. We conducted a genomic characterization of 113 MRSA clinical isolates from six Latin American healthcare centers, including 53 isolates collected from two cities in Chile (Santiago and Concepción). We found a plasmid (pSCL4752) harboring arsenic, cadmium, and mercury resistance genes in 65% ( <jats:italic>n</jats:italic> = 71) of the ST5-SCC <jats:italic>mec</jats:italic> I isolates. We also observed a geographic divergence associated with the presence of pSCL4752 in Chilean isolates, with a higher frequency in isolates from Concepción (88%) compared to Santiago (29%). Interestingly, a molecular clock analysis revealed that this divergence occurred in the aftermath of an 8.8 Mw earthquake and tsunami that struck the Concepción area in 2010. Moreover, our results demonstrate that the carriage of pSCL4752 can be beneficial or detrimental for ST5-SCC <jats:italic>mec</jats:italic> I isolates, depending on the environmental availability of these heavy metals. Our results suggest that the divergence of the ST5-SCC <jats:italic>mec</jats:italic> I MRSA lineage in Latin America could have been fostered by environmental disasters and influenced by the presence/absence of HMRGs harbored in a plasmid. </jats:p> <jats:sec> <jats:title>IMPORTANCE</jats:title> <jats:p> Methicillin-resistant <jats:italic>Staphylococcus aureus</jats:italic> (MRSA) is a major cause of life-threatening infections worldwide and a growing public health concern. The rise of antibiotic-resistant bacteria, such as MRSA, is often linked to genetic adaptations that enhance their survival. Our research sheds light on how environmental changes, such as those triggered by a natural disaster, can influence the evolution and geographic spread of a highly resistant MRSA lineage in Latin America. We identified a plasmid carrying genes for resistance to arsenic, cadmium, and mercury, which was associated with the geographic divergence of the ST5-SCC <jats:italic>mec</jats:italic> I MRSA lineage, with striking differences in its prevalence between regions affected by a major earthquake and tsunami. By linking environmental events to pathogen evolution, our study highlights the role of ecological pressures in the spread of MRSA. These findings emphasize the need to integrate environmental monitoring into public health strategies to better understand the global challenge of antimicrobial resistance.
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Static and Dynamic Loads on a Shallow Circular Tunnel: Practical Design Considerations
(2023)
MEDINA MOLINA, LUIS FELIPE
;
GUTIÉRREZ VEGA, CARLOS
;
LYON AUSENSI, BENJAMÍN
;
CANDIA AGUSTI, GABRIEL ALFONSO
7
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Adaptación y validación de la versión chilena de la escala de impacto de evento-revisada (EIE-R)
(2011)
Liliana Caamaño W
;
Diego Fuentes M
;
Luis González B
;
MELIPILLAN ARANEDA, EDMUNDO ROBERTO
;
Marcelo Sepúlveda C
Scopus© Citations 34 6
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Intensity measures properties and selection for risk analysis on structures subjected to earthquake induced pounding with a non-smooth contact dynamics method
(2021)
Langlade T.
;
Bertrand D.
;
Grange S.
;
CANDIA AGUSTI, GABRIEL
;
De la Llera J.C.
7Scopus© Citations 1
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A Computational Platform for the Assessment of Seismically-Induced Slope Displacements
(2020)
Jorge Macedo
;
CANDIA AGUSTI, GABRIEL ALFONSO
;
Norm Abrahamson
8
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Collapse risk assessment of a Chilean dual wall-frame reinforced concrete office building
(2019)
G. Araya-Letelier
;
P.F. Parra
;
D. Lopez-Garcia
;
A. Garcia-Valdes
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CANDIA AGUSTI, GABRIEL ALFONSO
Scopus© Citations 24 1
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Correlations of spectral accelerations in the Chilean subduction zone
(2020)
CANDIA AGUSTI, GABRIEL ALFONSO
;
Alan Poulos
;
Juan Carlos de la Llera
;
Jorge G.F. Crempien
;
Jorge Macedo
<jats:p> The correlation between spectral accelerations is key in the construction of conditional mean spectra, the computation of vector-valued seismic hazard, and the assessment of seismic risk of spatially distributed systems, among other applications. Spectral correlations are highly dependent on the earthquake database used, and thus, region-specific correlation models have been developed mainly for earthquakes in western United States, Europe, Middle East, and Japan. Correlation models based on global data sets for crustal and subduction zones have also become available, but there is no consensus about their applicability on a specific region. This study proposes a new correlation model for 5% damped spectral accelerations and peak ground velocity in the Chilean subduction zone. The correlations obtained were generally higher than those observed from shallow crustal earthquakes and subduction zones such as Japan and Taiwan. The study provides two illustrative applications of the correlation model: (1) computation of conditional spectra for a firm soil site located in Santiago, Chile and (2) computation of bivariate hazard for spectral accelerations at two structural periods. </jats:p>
Scopus© Citations 22 1
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Modelling of earthquake-induced pounding between adjacent structures with a non-smooth contact dynamics method
(2021)
T. Langlade
;
D. Bertrand
;
S. Grange
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CANDIA AGUSTI, GABRIEL ALFONSO
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J.C. de la Llera
7Scopus© Citations 12
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New developments for the performance-based assessment of seismically-induced slope displacements
(2020)
Jorge Macedo
;
CANDIA AGUSTI, GABRIEL ALFONSO
;
Maxime Lacour
;
Chenying Liu
Scopus© Citations 35 2
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Seismic risk of sliding ground-mounted rigid equipment
(2020)
Miguel A Jaimes
;
CANDIA AGUSTI, GABRIEL ALFONSO
7Scopus© Citations 16

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