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    Covid-19 in South America: clinical and epidemiological characteristics among 381 patients during the early phase of the pandemic in Santiago, Chile
    (2020)
    Macarena R. Vial
    ;
    Anne Peters
    ;
    Inia Pérez
    ;
    MarĂ­a Spencer-Sandino
    ;
    Mario Barbé
    <jats:title>Abstract</jats:title><jats:sec> <jats:title>Background</jats:title> <jats:p>Understanding the characteristics of the Covid-19 pandemic in different geographical regions, ethnic and socioeconomic settings are of emerging importance. This study presents the demographic and clinical features of SARS-CoV-2 infected patients in a large private healthcare center in Santiago, Chile, during the first month of the pandemic.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>We analyzed the demographics, laboratory and clinical characteristics including severity and outcome of all patients diagnosed with Covid-19 during the first month of the pandemic. SARS-2-CoV infection was confirmed by RT-PCR in nosopharyngeal samples. The primary outcome was a composite of ICU admission or all-cause, in-hospital mortality. Clinical and laboratory parameters of hospitalized patients were analyzed regarding their association with the primary outcome.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>From March 3 to April 4, 2020, 3679 individuals were tested for SARS-CoV-2 in our hospital. Of those, 381 had Covid-19 and were included into this analysis. Most patients (99.2%) were Chileans, 12% returning from recent travel. The median age was 39 years (IQR 31–49) and 52% were female. A total of 88 patients (23.1%) were hospitalized; 18 (3.7%) required ICU and/or died. The overall mortality was 0.7%. Increased body mass index (BMI) and elevated C-reactive protein (CRP) were independently associated with ICU care or death.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>During the first weeks of the pandemic in Chile, most Covid-19 patients were young, with low rates of hospitalization, ICU requirement, and fatality. BMI and CRP on admission were predictors for severity. Our data provide important information on the clinical course and outcome of Covid-19 in a Latin American setting.</jats:p> </jats:sec>
      1Scopus© Citations 15  3
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    Managing All the Genotypic Knowledge: Approach to a Septic Patient Colonized by Different Enterobacteriales with Unique Carbapenemases
    (2019)
    Stacy C. Park
    ;
    Alexander M. Wailan
    ;
    Katie E. Barry
    ;
    Kasi Vegesana
    ;
    Joanne Carroll
    <jats:p> The recent development of new antimicrobials active against carbapenemase-producing <jats:italic>Enterobacteriales</jats:italic> (CPE) has brought new hope for the treatment of infections due to these organisms. However, the evolving epidemiology of bacteria with carbapenemases may complicate management, as providers are faced with treating patients colonized by bacteria producing multiple carbapenemases. </jats:p>
    Scopus© Citations 7  1
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    Phenotypic and Genotypic Characterization of Macrolide, Lincosamide and Streptogramin B Resistance among Clinical Methicillin-Resistant Staphylococcus aureus Isolates in Chile
    (2022)
    Mario Quezada-Aguiluz
    ;
    Alejandro Aguayo-Reyes
    ;
    Cinthia Carrasco
    ;
    Daniela MejĂ­as
    ;
    Pamela Saavedra
    <jats:p>Macrolides, lincosamides, and type B streptogramins (MLSB) are important therapeutic options to treat methicillin-resistant Staphylococcus aureus (MRSA) infections; however, resistance to these antibiotics has been emerging. In Chile, data on the MLSB resistance phenotypes are scarce in both community-(CA) and hospital-acquired (HA) MRSA isolates. Antimicrobial susceptibility to MLSB was determined for sixty-eight non-repetitive isolates of each HA-(32) and CA-MRSA (36). Detection of SCCmec elements, ermA, ermB, ermC, and msrA genes was performed by PCR. The predominant clones were SCCmec I-ST5 (HA-MRSA) and type IVc-ST8 (CA-MRSA). Most of the HA-MRSA isolates (97%) showed resistance to clindamycin, erythromycin, azithromycin, and clarithromycin. Among CA-MRSA isolates, 28% were resistant to erythromycin, azithromycin, and 25% to clarithromycin. All isolates were susceptible to linezolid, vancomycin, daptomycin and trimethoprim/sulfamethoxazole, and over 97% to rifampicin. The ermA gene was amplified in 88% of HA-MRSA and 17% of CA-MRSA isolates (p &lt; 0.001). The ermC gene was detected in 6% of HA-SARM and none of CA-SARM isolates, whereas the msrA gene was only amplified in 22% of CA-MRSA (p &lt; 0.005). Our results demonstrate the prevalence of the cMLSB resistance phenotype in all HA-MRSA isolates in Chile, with the ermA being the predominant gene identified among these isolates.</jats:p>
    Scopus© Citations 7  3
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    ESBL-Producing Escherichia coli Carrying CTX-M Genes Circulating among Livestock, Dogs, and Wild Mammals in Small-Scale Farms of Central Chile
    (2021)
    Julio A. Benavides
    ;
    MarĂ­lia Salgado-Caxito
    ;
    Andrés Opazo-Capurro
    ;
    Paulina González Muñoz
    ;
    Ana Piñeiro
    Antibiotic-resistant bacteria of critical importance for global health such as extended-spectrum beta-lactamases-producing (ESBL)-Escherichia coli have been detected in livestock, dogs, and wildlife worldwide. However, the dynamics of ESBL-E. coli between these animals remains poorly understood, particularly in small-scale farms of low and middle-income countries where contact between species can be frequent. We compared the prevalence of fecal carriage of ESBL-E. coli among 332 livestock (207 cows, 15 pigs, 60 horses, 40 sheep, 6 goats, 4 chickens), 82 dogs, and wildlife including 131 European rabbits, 30 rodents, and 12 Andean foxes sharing territory in peri-urban localities of central Chile. The prevalence was lower in livestock (3.0%) and wildlife (0.5%) compared to dogs (24%). Among 47 ESBL-E. coli isolates recovered, CTX-M-group 1 was the main ESBL genotype identified, followed by CTX-M-groups 2, 9, 8, and 25. ERIC-PCR showed no cluster of E. coli clones by either host species nor locality. To our knowledge, this is the first report of ESBL-E. coli among sheep, cattle, dogs, and rodents of Chile, confirming their fecal carriage among domestic and wild animals in small-scale farms. The high prevalence of ESBL-E. coli in dogs encourages further investigation on their role as potential reservoirs of this bacteria in agricultural settings.
    Scopus© Citations 54  3
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    Longitudinal assessment of SARS-CoV-2 IgG seroconversionamong front-line healthcare workers during the first wave of the Covid-19 pandemic at a tertiary-care hospital in Chile
    (2021) ;
    Macarena R. Vial
    ;
    Maria Spencer-Sandino
    ;
    Pablo Gaete
    ;
    Anne Peters
    <jats:title>Abstract</jats:title><jats:sec> <jats:title>Background</jats:title> <jats:p>Healthcare workers (HCWs) are at high risk of exposure to SARS-CoV-2. Cross-sectional studies have provided variable rates of seroprevalence in HCWs. Longitudinal assessments of the serological response to Covid-19 among HCWs are crucial to understanding the risk of infection and changes in antibody titers over time. We aimed to investigate seroprevalence and risk factors associated with seroconversion in a prospective cohort of HCWs during the peak of the first wave of the Covid-19 pandemic.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>We conducted a longitudinal study among 446 front-line HCWsin a tertiary-care hospital in Chile from April to July 2020. IgG was determined monthly using two different ELISAs in serum samples of HCWs, during the three-month period. In each visit, demographic data, symptoms, risk factors, and exposure risks were also assessed.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>The overall seroprevalence at the end of the study period was 24% (95% CI20.2–28.3), with 43% of seropositive HCWs reporting no prior symptoms. Seroconversion rates significantly differed over the study period, from 2.1% to as high as 8.8% at the peak of the epidemic. There were no statistically significant differences observed between HCWs in direct clinical care of patients with Covid-19 and those working in low risk areas. Antibody titers appeared to wane over time.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>HCWs were severely affected with a high rate of seroconversion that appeared to mirror the local epidemiological situation. A significant amount of participants underwent an asymptomatic infection, highlighting the need for improved surveillance policies. Antibody titers appear to wane over time; further studies to understand this finding’s impact on the risk of reinfection are warranted.</jats:p> </jats:sec>
      1Scopus© Citations 21  2
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    Scopus© Citations 20  1
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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. MartĂ­nez
    ;
    Manuel Alcalde-Rico
    ;
    EstefanĂ­a 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 ConcepciĂłn). 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 ConcepciĂłn (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 ConcepciĂłn 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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    Genomic Epidemiology of Vancomycin-Resistant Enterococcus faecium (VREfm) in Latin America: Revisiting The Global VRE Population Structure
    (2020)
    Rafael Rios
    ;
    Jinnethe Reyes
    ;
    Lina P. Carvajal
    ;
    Sandra Rincon
    ;
    Diana Panesso
    <jats:title>Abstract</jats:title><jats:p>Little is known about the population structure of vancomycin-resistant <jats:italic>Enterococcus faecium</jats:italic> (VR<jats:italic>Efm</jats:italic>) in Latin America (LATAM). Here, we provide a complete genomic characterization of 55 representative Latin American VR<jats:italic>Efm</jats:italic> recovered from 1998–2015 in 5 countries. The LATAM VR<jats:italic>Efm</jats:italic> population is structured into two main clinical clades without geographical clustering. Using the LATAM genomes, we reconstructed the global population of VR<jats:italic>Efm</jats:italic> by including 285 genomes from 36 countries spanning from 1946 to 2017. In contrast to previous studies, our results show an early branching of animal related isolates and a further split of clinical isolates into two sub-clades within clade A. The overall phylogenomic structure of clade A was highly dependent on recombination (54% of the genome) and the split between clades A and B was estimated to have occurred more than 2,765 years ago. Furthermore, our molecular clock calculations suggest the branching of animal isolates and clinical clades occurred ~502 years ago whereas the split within the clinical clade occurred ~302 years ago (previous studies showed a more recent split between clinical an animal branches around ~74 years ago). By including isolates from Latin America, we present novel insights into the population structure of VR<jats:italic>Efm</jats:italic> and revisit the evolution of these pathogens.</jats:p>
      1Scopus© Citations 47  1