Marlon Barraza

Mr. Marlon Barraza

orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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13 May 2024 in Viruses
Verified
Journal Article
Open access
PDF file
GIGiannina Izquierdo
Giannina Izquierdo
CGCarolina Guerra
Carolina Guerra
RRRoberto Reyes
Roberto Reyes
LALeslie Araya
Leslie Araya
BSBelén Sepúlveda
Belén Sepúlveda
JTJuan Pablo Torres
Juan Pablo Torres
Background: Several screening strategies for identifying congenital CMV (cCMV) have been proposed; however, the optimal solution has yet to be determined. We aimed to determine the prevalence of cCMV by universal screening with saliva pool testing and to identify the clinical variables associated with a higher risk of cCMV to optimize an expanded screening strategy. Methods: We carried out a prospective universal cCMV screening (September/2022 to August/2023) of 2186 newborns, analyzing saliva samples in pools of five (Alethia-LAMP-CMV®) and then performed confirmatory urine CMV RT-PCR. Infants with risk factors (small for gestational age, failed hearing screening, HIV-exposed, born to immunosuppressed mothers, or <1000 g birth weight) underwent expanded screening. Multivariate analyses were used to assess the association with maternal/neonatal variables. Results: We identified 10 infants with cCMV (prevalence: 0.46%, 95% CI 0.22–0.84), with significantly higher rates (2.1%, 95% CI 0.58–5.3) in the high-risk group (p = 0.04). False positives occurred in 0.09% of cases. No significant differences in maternal/neonatal characteristics were observed, except for a higher prevalence among infants born to non-Chilean mothers (p = 0.034), notably those born to Haitian mothers (1.5%, 95% CI 0.31–4.34), who had higher odds of cCMV (OR 6.82, 95% CI 1.23–37.9, p = 0.04). Incorporating maternal nationality improved predictive accuracy (AUC: 0.65 to 0.83). Conclusions: For low-prevalence diseases such as cCMV, universal screening with pool testing in saliva represents an optimal and cost-effective approach to enhance diagnosis in asymptomatic patients. An expanded screening strategy considering maternal nationality could be beneficial in resource-limited settings.

1 August 2018 in Revista chilena de infectología
Verified
Journal Article
Open access
PDF file
MBMarlon Barraza
Marlon Barraza
NBNatalia Barnafi
Natalia Barnafi
GOGuillermo Ortiz
Guillermo Ortiz
JTJuan Pablo Torres
Juan Pablo Torres
PCPaulina Coria
Paulina Coria
JVJorge Morales Vallespín
Jorge Morales Vallespín
Palabras clave: Enfermedad fúngica invasora; antifúngicos; antifungal stewardship; impacto económico

13 January 2026 in Journal of Fungi
Verified
Journal Article
Open access
PDF file
MBMarlon Barraza
Marlon Barraza
RVRomina Valenzuela
Romina Valenzuela
VGValentina Gutierrez
Valentina Gutierrez
CGClaudia Greppi
Claudia Greppi
AÁAna M. Álvarez
Ana M. Álvarez
MSMaria Elena Santolaya
Maria Elena Santolaya
Invasive fungal disease (IFD) is one of the leading causes of morbidity and mortality in immunocompromised pediatric patients. This is a multicenter prospective cohort study with a nested retrospective analysis aimed at identifying risk factors for IFD in immunocompromised children with cancer and episodes of persistent high-risk febrile neutropenia (HRFN). One hundred and seventy-four episodes of persistent HRFN were analyzed, of which 34 (19.5%) were confirmed as IFD, 52.9% were caused by filamentous fungi, and 47.1% by yeasts. Logistic regression and survival analyses identified the following significant risk factors for IFD: male sex (OR 4.04), adolescence (OR 4.65), C-reactive protein ≥ 90 mg/L at admission (OR 3.13), and transfer to a critical care unit (OR 10.73). The predictive model demonstrated strong discriminatory capacity (AUC 0.84), with 79.4% sensitivity and 82.1% specificity. These findings highlight that adolescents, particularly males with severe clinical conditions and elevated inflammatory markers, are at the highest risk for IFD during episodes of HRFN. The proposed risk factor-based model may support early risk stratification and guide targeted antifungal prophylaxis or therapy, potentially improving outcomes in this population. Validation an external cohort is required to confirm these results and optimize clinical applicability.

1 February 2022 in Revista chilena de infectología
Verified
Journal Article
Open access
PDF file
MBMarlon Barraza
Marlon Barraza
JTJuan P. Torres
Juan P. Torres
PCPaulina Coria
Paulina Coria
RMRené Miranda
René Miranda
JPJulia Palma
Julia Palma
JMJorge Morales
Jorge Morales
Palabras clave: voriconazol; aspergilosis; concentración plasmática; monitorización terapéutica de fármacos

13 August 2026 in Antibiotics
Verified
Journal Article
Open access
PDF file
Carolina Ibanez IbanezCarolina Ibanez Ibanez
Carolina Ibanez Ibanez
RVRomina Valenzuela
Romina Valenzuela
MBMarlon Barraza
Marlon Barraza
AÁAna M. Álvarez
Ana M. Álvarez
EPErnesto Paya
Ernesto Paya
MSMaria Elena Santolaya
Maria Elena Santolaya
Background/Objectives: The objective of this study is to evaluate the efficacy and safety of maintaining antimicrobial (AM) therapy or adjusting AM therapy during episodes of febrile neutropenia (FN) catalogued as a fever of unknown origin (FUO) in children with cancer. Methods: This is a prospective, multicenter, noninferiority, randomized study, approved by ethics committee, in children with episodes of FN in eight hospitals in Chile. Microbiological and molecular samples were drawn at admission. Patients with FUO (negative bacterial and viral study with no clinical focus suggesting infection) and favorable evolution during the first 48–72 h of AM therapy were randomized 1:1 to maintain or adjust treatment, reducing the number and spectrum of AMs. The primary endpoint was the percentage of episodes with an uneventful resolution; the secondary endpoints were the re-adjustment of AM therapy, days of fever/hospitalization/AM therapy, days of vancomycin and meropenem per 1000 days of neutropenia, number of AMs after randomization, pediatric intensive care unit (PICU) admission, sepsis, and death. Results: A total of 266 of 939 FN episodes recruited between March 2021 and January 2024 were catalogued as FUO, of which 231 had a favorable evolution at 48–72 h and were randomized, 111 to maintain and 120 to adjust AM therapy. Both groups presented the same percentage of uneventful resolution, with 106 (96%) in the group that maintain AM therapy and 114 (95%) in the adjusted group (p = 1.00); relative risk 1.01, (95%CI 0.95–1.06); absolute risk difference 0.01, (95%CI −0.05–0.06). Conclusions: The main finding of this study demonstrates that adjusting antimicrobial therapy appears safe in carefully selected FUO cases with a favorable early evolution, during episodes of FN catalogued as FUO in children with cancer. These findings open an opportunity to new AM stewardship strategies in this population, with a possible future impact on AM resistance.

30 October 2025 in Preprints.org
Verified
Preprint
Open access
PDF file
MBMarlon Barraza
Marlon Barraza
RVRomina Valenzuela
Romina Valenzuela
VGValentina Gutierrez
Valentina Gutierrez
CGClaudia Greppi
Claudia Greppi
AAAna María Alvarez
Ana María Alvarez
MSMaria Elena Santolaya
Maria Elena Santolaya
Invasive fungal disease (IFD) is one of the leading causes of morbidity and mortality in immunocompromised pediatric patients. This is a multicenter prospective cohort study with a nested retrospective analysis aimed to identify risk factors for IFD in immunocompromised children with cancer and episodes of persistent high-risk febrile neutropenia (HRFN). One hundred and seventy-four episodes of persistent HRFN were analyzed, of which 34 (19.5%) were confirmed as IFD, 52.9% caused by filamentous fungi and 47.1% by yeasts. Logistic regression and survival analyses identified the following significant risk factors for IFD: male sex (OR 4.04), adolescence (OR 4.65), C-reactive protein ≥ 90 mg/L at admission (OR 3.13), and transfer to a critical care unit (OR 10.73). The predictive model demonstrated strong discriminatory capacity (AUC 0.84), with 79.4% sensitivity and 82.1% specificity. These findings highlight that adolescent, particularly males with severe clinical conditions and elevated inflammatory markers, are at highest risk for IFD during episodes of HRFN. The proposed risk factors-based model may support early risk stratification and guide targeted antifungal prophylaxis or therapy, potentially improving outcomes in this population. Validation in external cohort is required to confirm these results and optimize clinical applicability.