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Activity of novel antibiotics against dual metallo-Beta-lactamase producing
<i>Enterobacter hormaechei</i>
clinical isolates
(Oxford University Press (OUP), 2026-01-07)
Camila Solar
;
LORENA DIAZ BAYO
;
Katherine Soto
;
Jose R W Martínez
;
Nicolas Canales
<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Background</jats:title> <jats:p>Metallo-β-lactamase (MBL)-producing carbapenemase-resistant Enterobacterales infections are associated with significant mortality. Several β-lactam/β-lactamase inhibitor combinations (BL/BLI) with promising activity against MBLs are in the pipeline.</jats:p> </jats:sec> <jats:sec> <jats:title>Objective</jats:title> <jats:p>To investigate the in vitro activity of upcoming BL/BLI agents against Enterobacter hormaechei clinical isolates co-producing NDM and VIM enzymes.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Eleven E. hormaechei isolates co-harbouring blaNDM-7 and blaVIM-1 were identified from 10 patients admitted to a tertiary hospital in Santiago, Chile, between July 2022 and July 2023. Reference broth microdilution (BMD) panels were developed to determine minimum inhibitory concentrations (MICs) to aztreonam/avibactam, cefepime/taniborbactam, cefepime/zidebactam, cefiderocol and cefiderocol/xeruborbactam. Cefiderocol population analysis profile–area under the curve (PAP–AUC) was performed in strains exhibiting cefiderocol susceptibility to assess for cefiderocol heteroresistance. Long-read sequencing, using the Oxford Nanopore Technologies platform, was conducted on all isolates to characterize the genomic background of blaNDM-7 and blaVIM-1.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Among the 11 E. hormaechei isolates assemblies revealed blaNDM-7 and blaVIM-1 were located on separate plasmids. All isolates were susceptible to aztreonam/avibactam, cefepime/taniborbactam and cefepime/zidebactam. Cefiderocol susceptibility was variable; the addition of xeruborbactam restored susceptibility.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Our findings indicate that E. hormaechei clinical isolates co-producing NDM and VIM metallo-carbapenemases exhibited susceptibility to all tested novel BL/BLIs, including aztreonam/avibactam, cefepime/taniborbactam and cefepime/zidebactam. The combination of cefiderocol and xeruborbactam restored the activity of cefiderocol.</jats:p> </jats:sec>
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Actividad in vitro de ceftazidima/avibactam contra aislados clínicos de Klebsiella pneumoniae resistente a carbapenémicos y comparación de técnicas de susceptibilidad
(SciELO Agencia Nacional de Investigacion y Desarrollo (ANID), 2025-06)
Valeria Quiroz
;
RIVAS JIMENEZ, LINA MARIA
;
Katherine Soto
;
Yohanna Antolínez
;
Valentina Sanfurgo
7
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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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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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Performance of the VITEK® MS system for the identification of filamentous fungi in a microbiological laboratory in Chile
(Public Library of Science (PLoS), 2024-12-23)
PORTE TORRE, LORENA ISABEL
;
Rodrigo Cruz
;
Pérez Villa, Inia
;
Carmen Varela
;
Cristina Díaz
<jats:p>Filamentous fungi are an emergent cause of severe infections in immunocompromised patients. Timely and accurate identification is crucial to initiate appropriate therapy. Traditional identification methods are time-consuming, labor-intensive, and operator-dependent. Matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry is a rapid and easy-to-perform identification method. The effectiveness of a commercial MALDI-TOF MS platform to identify filamentous fungi in a clinical laboratory was evaluated. The study included 67 fungal isolates from 35 species/species complexes, which were identified and confirmed in mycology reference laboratories; 32 derived from clinical samples, 34 from strain collections and one was an ATCC strain. The study used the VITEK<jats:sup>®</jats:sup> MS system (v3.2.0 database), after sample extraction by VITEK<jats:sup>®</jats:sup> MS Mould Kit. Results were classified as “correct species”, “correct species complex”, “correct genus”and “no identification”. VITEK<jats:sup>®</jats:sup> MS correctly identified 91.0% of isolates (58.2% to species, 29.9% to species complex, and 1.5% to genus level only). In 82%, the result matched the species/species complex identified by reference methods. No misidentifications were observed. The kit was rapid and easy to use. In conclusion, the VITEK<jats:sup>®</jats:sup> MS system showed a high capability to accurately identify filamentous fungi in a clinical laboratory.</jats:p>
1
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Salmonella enterica Serovar Abony Outbreak Caused by Clone of Reference Strain WDCM 00029, Chile, 2024
(Centers for Disease Control and Prevention (CDC), 2025-01)
Alejandro Piña-Iturbe
;
Diego Fredes-García
;
Patricia García
;
PORTE TORRE, LORENA ISABEL
;
Timothy J. Johnson
Scopus© Citations 1 1
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LINC00662 Promotes Aggressive Traits by Modulating OCT4 Expression through miR-335-5p in Gallbladder Cancer Cells
(2024)
Pablo Pérez-Moreno
;
Ismael Riquelme
;
Carolina Bizama
;
Luis Vergara-Gómez
;
Julio C. Tapia
<jats:p>Long non-coding RNAs (lncRNAs) are nucleotide sequences that participate in different biological processes and are associated with different pathologies, including cancer. Long intergenic non-protein-coding RNA 662 (LINC00662) has been reported to be involved in different cancers, including colorectal, prostate, and breast cancer. However, its role in gallbladder cancer has not yet been described. In this article, we hypothesize that LINC00662 has an important role in the acquisition of aggressiveness traits such as a stem-like phenotype, invasion, and chemoresistance in gallbladder cancer. Here, we show that LINC00662 is associated with larger tumor size and lymph node metastasis in patients with gallbladder cancer. Furthermore, we show that the overexpression of LINC00662 promotes an increase in CD133+/CD44+ cell populations and the expression of stemness-associated genes. LINC00662 promotes greater invasive capacity and the expression of genes associated with epithelial–mesenchymal transition. In addition, the expression of LINC00662 promotes resistance to cisplatin and 5-fluorouracil, associated with increased expression of chemoresistance-related ATP-binding cassette (ABC) transporters in gallbladder cancer (GBC) cell lines. Finally, we show that the mechanism by which LINC00662 exerts its function is through a decrease in microRNA 335-5p (miR-335-5p) and an increase in octamer-binding transcription factor 4 (OCT4) in GBC cells. Thus, our data allow us to propose LINC00662 as a biomarker of poor prognosis and a potential therapeutic target for patients with GBC.</jats:p>
1Scopus© Citations 2
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Catheter-associated bloodstream infection caused by Leifsonia aquatica in a haemodialysis patient: a case report
(2012)
Lorena Porte
;
Andrés Soto
;
Daniela Andrighetti
;
Jeannette Dabanch
;
Stephanie Braun
Scopus© Citations 16 3
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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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Chromosome-Mediated Colistin Resistance in Clinical Isolates of Klebsiella pneumoniae and Escherichia coli: Mutation Analysis in the Light of Genetic Background
(2023)
María Paz Riquelme
;
Jose Rodrigo W Martínez
;
Bárbara Brito
;
Patricia García
;
Paulette Legarraga
Scopus© Citations 4 2

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