Browsing by Author "Carvajal, Lina P."

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    Dynamics of the MRSA Population in a Chilean Hospital: a Phylogenomic Analysis (2000-2016)
    (2023) Martinez, Jose R. W.; Planet, Paul J.; Spencer-Sandino, Maria; Rivas, Lina; Diaz, Lorena; Moustafa, Ahmed M.; Quesille-Villalobos, Ana; Riquelme-Neira, Roberto; Alcalde-Rico, Manuel; Hanson, Blake; Carvajal, Lina P.; Rincon, Sandra; Reyes, Jinnethe; Lam, Marusella; Calderon, Juan F.; Araos, Rafael; Garcia, Patricia; Arias, Cesar A.; Munita, Jose M.
    Methicillin-resistant Staphylococcus aureus (MRSA) is a major public health pathogen that disseminates through the emergence of successful dominant clones in specific geographic regions. Knowledge of the dissemination and molecular epidemiology of MRSA in Latin America is scarce and is largely based on small studies or more limited typing techniques that lack the resolution to represent an accurate description of the genomic landscape.
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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
    (2025) Martínez, José R. W.; Alcalde-Rico, Manuel; Jara-Videla, Estefanía; Reyes, Jinnethe; Carvajal, Lina P.; Sandra Rincon; Ríos, Rafael; Diaz, Lorena; Quesille-Villalobos, Ana; Riquelme-Neira, Roberto; Rivas, Lina; Moustafa, Ahmed M.; Blake, Hanson; Undurraga, Eduardo A.; Olivares-Pacheco, Jorge; García Cañete, Patricia; Araos, Rafael; Planet, Paul J.; Arias, César A.; Munita, José M.
    Methicillin-resistant Staphylococcus aureus (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-SCCmecI 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% (n = 71) of the ST5-SCCmecI 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-SCCmecI isolates, depending on the environmental availability of these heavy metals. Our results suggest that the divergence of the ST5-SCCmecI MRSA lineage in Latin America could have been fostered by environmental disasters and influenced by the presence/absence of HMRGs harbored in a plasmi.
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    Heavy Metal Pollution From a Major Earthquake and Tsunami in Chile Is Associated With Geographic Divergence of Clinical Isolates of Methicillin-Resistant Staphylococcus aureus in Latin America
    Martínez, José R.W.; Alcalde-Rico, Manuel; Jara-Videla, Estefanía; Ríos, Rafael; Moustafa, Ahmed M.; Blake, Hanson; Rivas, Lina; Carvajal, Lina P.; Rincon, Sandra; Díaz, Lorena; Jinnethe Reyes, Jinnethe; Quesille-Villalobos, Ana; Riquelme-Neira, Roberto; Undurraga, Eduardo A.; Olivares-Pacheco, Jorge; García Cañeta, Patricia del Carmen; Araos, Rafael; Planet, Paul J.; Arias, César A.; Munita, José M.
    Methicillin-resistant Staphylococcus aureus (MRSA) is a priority pathogen listed by the World Health Organization. The global spread of MRSA is characterized by successive waves of epidemic clones that predominate in specific geographical regions. The acquisition of genes encoding resistance to heavy-metals is thought to be a key feature in the divergence and geographical spread of MRSA. Increasing evidence suggests that extreme natural events, such as earthquakes and tsunamis, could release heavy-metals into the environment. However, the impact of environmental exposition to heavy-metals on the divergence and spread of MRSA clones has been insufficiently explored. We assess the association between a major earthquake and tsunami in an industrialized port in southern Chile and MRSA clone divergence in Latin America. We performed a phylogenomic reconstruction of 113 MRSA clinical isolates from seven Latin American healthcare centers, including 25 isolates collected in a geographic area affected by an earthquake and tsunami that led to high levels of heavy-metal environmental contamination. We found a divergence event strongly associated with the presence of a plasmid harboring heavy-metal resistance genes in the isolates obtained in the area where the earthquake and tsunami occurred. Moreover, clinical isolates carrying this plasmid showed increased tolerance to mercury, arsenic, and cadmium. We also observed a physiological burden in the plasmid-carrying isolates in absence of heavy-metals. Our results are the first evidence that suggests that heavy-metal contamination, in the aftermath of an environmental disaster, appears to be a key evolutionary event for the spread and dissemination of MRSA in Latin America.