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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.
4
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Multispecies emergence of dual blaKPC/NDM carbapenemase-producing Enterobacterales recovered from invasive infections in Chile
(American Society for Microbiology, 2025-01-31)
QUESILLE VILLALOBOS, ANA MARIA
;
Camila Solar
;
Jose R. W. Martínez
;
RIVAS JIMENEZ, LINA MARIA
;
Valeria Quiroz
Carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE) represent a significant global threat. The emergence of dual CP-CRE is particularly alarming, as they can potentially compromise the efficacy of newer antibiotics, further decreasing therapeutic alternatives. Herein, we report the emergence of multiple species of CP-CRE recovered from invasive infections in Chile that simultaneously harbor and provide an in-depth genomic characterization of these worrisome pathogens. We collected carbapenem-resistant Enterobacterales (CRE) isolates from invasive infections over a 4-year period, across 11 healthcare centers in Chile. Bacterial species and the presence of carbapenemase genes were confirmed using MALDI-TOF and PCR assays, respectively. Antimicrobial susceptibility testing was conducted through disk diffusion and broth microdilution methods. Dual CP-CRE isolates were subjected to short- and long-read whole genome sequencing to perform a detailed genomic characterization of the isolates and of the mobile genetic elements harboring the enzymes. From a total of 1,335 CRE isolates, we observed an increase in the prevalence of CP-CRE, from 11% in 2019 to 38% in 2022. A total of 11 dual CP-CRE isolates were recovered, all of them harboring
Scopus© Citations 10 15
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Dynamics of the MRSA Population in a Chilean Hospital: a Phylogenomic Analysis (2000–2016)
(2023)
José R. W. Martínez
;
Paul J. Planet
;
Maria Spencer-Sandino
;
RIVAS JIMENEZ, LINA MARIA
;
Ahmed M. Moustafa
<jats:p> Methicillin-resistant <jats:named-content content-type="genus-species">Staphylococcus aureus</jats:named-content> (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. </jats:p>
Scopus© Citations 6 4
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Antibiotic Consumption During the Coronavirus Disease 2019 Pandemic and Emergence of Carbapenemase-Producing <i>Klebsiella pneumoniae</i> Lineages Among Inpatients in a Chilean Hospital: A Time-Series Study and Phylogenomic Analysis
(2023)
Kasim Allel
;
Anne Peters
;
José Conejeros
;
José R W Martínez
;
Maria Spencer-Sandino
<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>The impact of coronavirus disease 2019 (COVID-19) on antimicrobial use (AU) and resistance has not been well evaluated in South America. These data are critical to inform national policies and clinical care.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>At a tertiary hospital in Santiago, Chile, between 2018 and 2022, subdivided into pre- (3/2018–2/2020) and post–COVID-19 onset (3/2020–2/2022), we evaluated intravenous AU and frequency of carbapenem-resistant Enterobacterales (CRE). We grouped monthly AU (defined daily doses [DDD]/1000 patient-days) into broad-spectrum β-lactams, carbapenems, and colistin and used interrupted time-series analysis to compare AU during pre- and post-pandemic onset. We studied the frequency of carbapenemase-producing (CP) CRE and performed whole-genome sequencing analyses of all carbapenem-resistant (CR) Klebsiella pneumoniae (CRKpn) isolates collected during the study period.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Compared with pre-pandemic, AU (DDD/1000 patient-days) significantly increased after the pandemic onset, from 78.1 to 142.5 (P &lt; .001), 50.9 to 110.1 (P &lt; .001), and 4.1 to 13.3 (P &lt; .001) for broad-spectrum β-lactams, carbapenems, and colistin, respectively. The frequency of CP-CRE increased from 12.8% pre–COVID-19 to 51.9% after pandemic onset (P &lt; .001). The most frequent CRE species in both periods was CRKpn (79.5% and 76.5%, respectively). The expansion of CP-CRE harboring blaNDM was particularly noticeable, increasing from 40% (n = 4/10) before to 73.6% (n = 39/53) after pandemic onset (P &lt; .001). Our phylogenomic analyses revealed the emergence of two distinct genomic lineages of CP-CRKpn: ST45, harboring blaNDM, and ST1161, which carried blaKPC.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>AU and the frequency of CP-CRE increased after COVID-19 onset. The increase in CP-CRKpn was driven by the emergence of novel genomic lineages. Our observations highlight the need to strengthen infection prevention and control and antimicrobial stewardship efforts.</jats:p> </jats:sec>
30Scopus© Citations 36
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Real-World Performance of Susceptibility Testing for Ceftolozane/Tazobactam against Non-Carbapenemase-Producing Carbapenem-Resistant Pseudomonas aeruginosa
(2022)
RIVAS JIMENEZ, LINA MARIA
;
Manuel Alcalde-Rico
;
José R. W. Martínez
;
María Victoria Moreno
;
Pamela Rojas
<jats:p> Ceftolozane/tazbactam (C/T) is a potent anti-pseudomonal agent that has clinical utility against infections caused by non-carbapenemase, producing-carbapenem-resistant <jats:named-content content-type="genus-species">Pseudomonas aeruginosa</jats:named-content> (non-CP-CR-PA). Accurate, precise, and reliable antimicrobial susceptibility testing (AST) is crucial to guide clinical decisions. </jats:p>
19Scopus© Citations 2
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A Multicenter Study To Evaluate Ceftaroline Breakpoints: Performance in an Area with High Prevalence of Methicillin-Resistant Staphylococcus aureus Sequence Type 5 Lineage
(2019)
Ayesha Khan
;
Lina M. Rivas
;
Maria Spencer
;
Rodrigo Martinez
;
Marusella Lam
<jats:p> Ceftaroline (CPT) is a broad-spectrum agent with potent activity against methicillin-resistant <jats:named-content content-type="genus-species">Staphylococcus aureus</jats:named-content> (MRSA). The sequence type 5 (ST5) Chilean-Cordobés clone, associated with CPT nonsusceptibility, is dominant in Chile, a region with high rates of MRSA infections. </jats:p>
1Scopus© Citations 7 1

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