Marcos Carbajal, Pool

Preferred name

Main Affiliation

poolmarcos@upeu.edu.pe

ORCID

0000-0002-7741-0337

Scopus Author ID

57192167433

Mostrando 1 - 10 de 30

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The Emergence of Sars-CoV-2 Variant Lambda (C.37) in South America
(2021-10-27)
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Alejandra Dávila-Barclay
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Guillermo Salvatierra
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Luis Ángel Suárez González
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Diego Cuicapuza
The evolution of SARS-CoV-2 variants with potentially increased transmissibility, virulence, and resistance to antibody neutralization poses new challenges for the control of COVID-19 (1), particularly in low- and middle-income countries (LMICs) where transmission remains high and vaccination progress is still incipient...
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Full Genome Analysis of Influenza A(H1N1)pdm09 Virus Isolated from Peru, 2013
(2014-04-18)
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Fredy J Condori
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Maribel Huaringa
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Nancy Rojas
The pandemic influenza A(H1N1)pdm09 virus has been reported in Peru since 2009. We report the whole-genome sequence analysis of a viral isolate from an infection case that occurred during an influenza outbreak in 2013. This strain shows novel hemagglutinin (HA) mutations that may cause an antigenic drift that diminishes the protective effect of the vaccine.
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Diversity and functionality of the gut microbiota in hypertensive patients from different regions of Peru
(2025-12-15)
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Milagros Nicole Villegas Suarez
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Vasty Vanessa Rafael ccama
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Miguel Otiniano-Trujillo
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<ns3:p> Introduction Arterial hypertension affects around 19.4% of Peruvians over 15 years old, constituting a major public health issue. Recent evidence highlights the gut microbiome’s role in regulating blood pressure through bioactive metabolites that influence inflammation and metabolism. This study aims to characterize the gut microbiota of hypertensive adults from three Peruvian regions, contributing to the understanding of microbial influences on hypertension. Objective To analyze the composition and functionality of the gut microbiota in hypertensive and normotensive adults from different Peruvian regions, considering age, body mass index (BMI), and geographical location. Methods An observational, cross-sectional, and analytical study was conducted with 84 adults (46 hypertensive and 38 normotensive) from nine regions of Peru. Fecal samples underwent metagenomic sequencing of the 16S rRNA gene (V3–V4 region). Alpha and beta diversity were evaluated using the Shannon index, UniFrac distances, and multivariate analyses. Microbial functional pathways were examined to identify potential metabolic differences between groups. Results The dominant phyla in all groups were Bacillota and Bacteroidota. At the genus level, <ns3:italic>Streptococcus</ns3:italic> was associated with hypertensive patients with BMI ≥25, while <ns3:italic>Alistipes</ns3:italic> appeared only in normotensive individuals with BMI <25. Alpha diversity was greater in hypertensive participants under 50 years and with BMI <25, while lower diversity was seen in normotensive adults over 50 and with BMI ≥25. Beta diversity showed partial clustering by hypertension and age, with regional overlap. Functional profiles were similar among groups, mainly involving carbohydrate, amino acid, and lipid metabolism, though BMI and age modulated these patterns. Conclusions Gut microbiota composition and diversity in Peruvian adults are influenced by hypertension, age, BMI, and region. Despite comparable functional profiles, environmental and nutritional factors may have a stronger impact than hypertension alone, offering insight for region-specific prevention and treatment strategies. </ns3:p>
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Influencia de la dieta vegetariana y carnívora en relación a la hemoglobina y hematocrito
(2020-06-30)
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Gonzalo Larico-Ayma
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Gabrielly Boeira-De Sousa
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The present study establishes the degree of influence of the vegetarian and carnivore diets on the hemoglobin and hematocrit levels of students of human medicine of the Universidad Peruana Unión, Lima, 2018. The goal was to find out if people who follow a vegetarian or carnivore diet are deficient in hematocrit and hemoglobin. Out of the vegetarians, 23 followed different types of vegetarianism. The following ranges were considered: hemoglobin (12 - 16 g/dL) and hematocrit (36 - 48 %). It is concluded that, regarding the diet and hemoglobin/hematocrit levels, most respondents show normal ranges, and people who follow a vegetarian diet do not present highly-deficient hematocrit and hemoglobin levels, and have a better nutritional level than those who follow a carnivore diet.
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Detection of SARS-CoV-2 variants in hospital wastewater in Peru, 2022
(2024-06-21)
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Miguel Otiniano-Trujillo
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Marco Galarza
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Abraham Espinoza-Culupú
OBJECTIVE.: To identify the presence of the SARS-CoV-2 virus in wastewater from hospitals in Peru. MATERIALS AND METHODS.: Water samples were collected from the effluents of nine hospitals in Peru during March and September 2022. SARS-CoV-2 was identified by using Illumina sequencing. Variant, lineage and clade assignments were carried out using the Illumina and Nextclado tools. We verified whether the SARS-CoV-2 variants obtained from wastewater were similar to those reported by the National Institute of Health of Peru from patients during the same period and region. RESULTS.: Eighteen of the 20 hospital wastewater samples (90%) provided sequences of sufficient quality to be classified as the Omicron variant according to the WHO classification. Among them, six (30%) were assigned by Nextclade to clades 21K lineage BA.1.1 (n=1), 21L lineage BA.2 (n=2), and 22B lineages BA.5.1 (n=2) and BA .5.5 (n=1). CONCLUSIONS.: SARS-CoV-2 variants were found in hospital wastewater samples and were similar to those reported by the surveillance system in patients during the same weeks and geographic areas. Wastewater monitoring could provide information on the environmental and temporal variation of viruses such as SARS-CoV-2. Motivation for the study. To contribute to the surveillance of environmental samples from hospital effluents in order to achieve early warning of possible infectious disease outbreaks. Main findings. The Omicron variant of the COVID-19 virus was detected in wastewater from hospitals in Puno, Cuzco and Cajamarca; these results are similar to the reports by the Peruvian National Institute of Health based on nasopharyngeal swab samples. Implications. The presence of the Omicron variant in hospital wastewater during the third wave of the pandemic should raise awareness of the treatment system before wastewater is discharged into the public sewer system.
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Pruebas moleculares para el diagnóstico de COVID-19: La respuesta de Sudamérica
(2021-11-15)
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Christian Allca-Muñoz
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Macarena Ganoza-Farro
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André Valdez-Olivera
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Luisa Alisson Gómez-Martel
Actualmente a nivel mundial se utiliza la reacción en cadena de la polimerasa con transcriptasa inversa (RT-PCR) como una técnica de alta precisión en la detección y amplificación de secciones específicas de la estructura génica. En tal sentido es considerado como prueba diagnóstica molecular en la detección del SARS-CoV-2. Se realizó una revisión de la literatura en artículos publicados en los últimos 5 años (2015 – 2020). Se consultaron las bases de datos: PUBMED (Medline), PUBMED CENTRAL, y SCIELO. Se recuperaron artículos en español, portugués, e inglés, mediante los términos de búsqueda SARS-CoV-2, RT-PCR, y COVID-19. Las RT-PCR que utilicen especímenes de hisopado nasal y faríngeos son considerados como gold standard en casos sospechosos de COVID-19. Mediante lo revisado a nivel de Sudamérica, la RT-PCR resultó ser la prueba de elección durante el período menor a 7 días de infección, resaltando la producción in house en escala por Uruguay y la Prueba de amplificación isotérmica mediada por bucle (RT-LAMP) adaptado en Perú, como una alternativa diagnóstica rápida con principios similares a la RT-PCR, solo que para establecimientos de salud con menor equipamiento, e infraestructura y personal entrenado. La disponibilidad de pruebas diagnósticas moleculares también es crucial para el aislamiento de casos positivos y el seguimiento de la cadena epidemiológica de transmisión.
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Elevada presencia de enterobacterias con genes de resistencia antimicrobiana en pacientes diagnosticados de COVID-19 en hospitales públicos del Perú
(2025-03-31)
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Carla Liñan-Martínez
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Alexander Fajardo-Loyola
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Rafael Remon-Chinchay
Objetivo: caracterizar fenotípica y genotípicamente, así como determinar la prevalencia, de genes de resistencia a betalactamasas de espectro extendido (BLEE), AMPc y carbapenemasas en aislamientos de bacterias gramnegativas obtenidos de pacientes con diagnóstico de COVID-19 en cinco centros de salud en Perú. Materiales y métodos: se llevó a cabo un estudio descriptivo y retrospectivo, analizando 78 aislamientos bacterianos de pacientes con COVID-19 recolectados durante el 2020. La identificación bacteriana y la interpretación de los perfiles de susceptibilidad antimicrobiana se realizaron mediante el sistema MicroScan®. La detección de los genes de resistencia blaCTX-M, blaTEM, blaSHV, blaAmpC, blaKPC, blaIMP y blaNDM se efectuó mediante reacción en cadena de la polimerasa (PCR). Resultados: de los aislamientos bacterianos analizados, 49 (62,83%) correspondieron a enterobacterias y 29 (37,17%) a bacterias gramnegativas no fermentadoras (GNNF). Escherichia coli fue la especie predominante, con 33 aislamientos (42,30%). En relación con las cepas productoras de fenotipos BLEE y carbapenemasas confirmadas por PCR, son 49 y 29, respectivamente. Se observó resistencia a antibióticos como cefotaxima, ciprofloxacino y aztreonam, mientras que la mayoría de las bacterias mostraron sensibilidad a ertapenem, colistina y tigeciclina. La PCR reveló que el gen blaCTX-M fue el más prevalente, detectado en el 25,64% de los aislamientos (20/78), y distribuido en los cinco hospitales estudiados. Conclusiones: los resultados indican una alta presencia de genes de resistencia bacteriana en las muestras estudiadas, destacando blaCTX-M y blaTEM en enterobacterias, y blaIMP en bacterias no fermentadoras. Estos hallazgos subrayan la necesidad de fortalecer la vigilancia de RAM en el contexto de la infección en pacientes con COVID-19.
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Acción antibacteriana de extractos corteza de Maytenus macrocarpa (Chuchuhuasi) contra cepas ATCC de Escherichia coli, Pseudomonas aeruginosa y Staphylococcus aureus
(2023-09-15)
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Christian Allca-Muñoz
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Juan Carlos Castro-Sánchez
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Luis Felipe Segura-Chavez
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Alberto Salazar‐Granara
El aumento de infecciones comunitarias como las hospitalarias a causa de infecciones por bacterias con resistencia a múltiples drogas antibióticas. Constituyen en la actualidad como uno de los problemas de mayor preocupación en salud pública global, generando la necesidad de poder encontrar nuevas alternativas terapéuticas, siendo así que se ha ampliado la búsqueda a través de los principios activos en plantas con efecto antimicrobiano. Maytenus macrocarpa ̈Chuchuhuasi ̈ es un árbol nativo de la región Amazónica del Perú utilizado como analgésico, antiinflamatorio y antioxidante. Este árbol se caracteriza por contener compuestos activos como triterpenoquinonas y dímeros triterpénicos los cuales pueden presentar actividad antimicrobiana. El objetivo del presente estudio fue determinar la acción antimicrobiana de flavonoides y alcaloides de Maytenus macrocarpa, contra las cepas de Pseudomonas aeruginosa ATCC 25923 y Escherichia coli ATCC 25922, determinándose la actividad antimicrobiana de los extractos mediante el método Kirby Bauer. Se encontró que las cepas de Pseudomonas aeruginosa ATCC 25923 y Escherichia coli ATCC 25922 fueron resistentes a todos los extractos de Maytenus macrocarpa, siendo sensible la cepa de Staphylococcus aureus ATCC 25923. Se concluye que los extractos de Maytenus macrocarpa no presentan actividad antimicrobiana frente a cepas gram negativas, pudiendo ser considerada una buena opción terapéutica frente a cepas gram positivas. Palabras Clave: Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Antibacterianos, Maytenus, Extractos vegetales (fuente: DeCS BIREME)
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Elevada presencia de enterobacterias con genes de resistencia antimicrobiana en pacientes diagnosticados de COVID-19 en hospitales públicos del Perú
(2025-03-31)
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Carla Liñan-Martínez
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Alexander Fajardo-Loyola
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Rafael Remon-Chinchay
Objective: To characterize phenotypic and genotypic profiles, and to determine the prevalence of extended-spectrum betalactamases (ESBLs), AmpC, and carbapenemase resistance genesin gram-negative isolates obtained from COVID-19 patients in five health centers in Peru. Materials and methods: A descriptive and retrospective study was conducted, analyzing 78 bacterial isolates from COVID-19 patients collected during 2020. Bacterial identification and interpretation of antimicrobial susceptibility profiles were performed using the MicroScan® system. Detection of resistance genes blaCTX-M, blaTEM, blaSHV, blaAmpC, blaKPC, blaIMP, and blaNDM was conducted using polymerase chain reaction (PCR). Results: Amongst bacterial isolates analyzed, 49 (62.83%) were Enterobacteriaceae, and 29 (37.17%) were non-fermenting gram-negative bacteria (NFGNB). Escherichia coli was the most prevalent species, with 33 isolates (42.30%). Resistance to antibacterials was observed, including cefotaxime, ciprofloxacin, and aztreonam, while most bacteria remained susceptible to ertapenem, colistin, and tigecycline. PCR analysis revealed that the blaCTX-M gene was the most prevalent, detected in 25.64% of isolates (20/78) and distributed across the five hospitals studied. Conclusions: The findings indicate a high prevalence of bacterial resistance genes in the samples studied, with blaCTX-M and blaTEM being most prevalent in Enterobacteriaceae and blaIMP in non-fermenting bacteria. These findings underscore the need to strengthen AMR surveillance in the context of coinfection in COVID-19 patients.
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Distribución de frecuencias del polimorfismo T1236C en el gen ABCB1 en las poblaciones peruanas y comparación con poblaciones de América, Asia, Europa y África
(2025-09-11)
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Alberto Salazar Granara
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médico cirujano.
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José Sandoval Sandoval
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Universidad de San Martín de Porres, Facultad de Medicina Humana, Centro de Investigación de Genética y Biología Molecular. Lima, Perú. Licenciado en biología; doctor en Filosofía.
Objective: Mutations in the ABCB1 gene have an impact on the response to various drugs and may be associated with the development of neoplasms. This study explores and compares the frequency distribution of the 1236T>C polymorphism in theABCB1 gene among nine Peruvian populations from different geographical origins and altitudes, as well as the genotype/allele frequencies reported in populations from various continents worldwide. Materials and methods: Sampling was carried out in the following departments and localities: Lima (n = 8), Loreto–Andoas (n = 16), San Martín–Lamas (n = 16), Puno–Uros (n = 7), Puno–Taquile (n = 5), Arequipa–Chivay (n = 10), Arequipa–Cabanaconde (n = 6), Ancash–Parobamba (n = 10), and Apurímac–Andahuaylas (n = 10). Biological samples (peripheral blood and/or epithelial cells) were collected via buccal swabs. Deoxyribonucleic acid (DNA) was extracted using a standard protocol. The 1236T>C polymorphism (rs1128503) was identified using real-time polymerase chain reaction (PCR). Variables were categorized by geographical origin (coast, highlands, or jungle) and altitude (< 2,500 or > 2,500meters above sea level [m a.s.l.]). Statistical analyses included the Hardy–Weinberg equilibrium and Pearson’s chi-square test, with a significance level of p < 0.05 and a 95 % confidence interval (95 % CI). Results: The frequency distribution of the 1236T>Cpolymorphism in the ABCB1 gene was determined for the Peruvian populations studied. Across coastal, highland, and jungle regions, the heterozygous C/T genotype (associated with intermediate P-glycoprotein activity) was the most prevalent, with thehighest frequency (60 %) observed on Taquile Island (Lake Titicaca, Puno). In the overall Peruvian sample (n = 88), the frequency of the C/T genotype was 43 % at < 2,500 and 50 % at > 2,500 m a.s.l. In contrast, the homozygous C/C (normal activity) and T/T (slow activity) genotypes showed similar frequencies at < 2,500 m a.s.l. (30 % and 28 %, respectively) but differed at > 2,500 m a.s.l. (35 % and 15 %, respectively). The overall genotype distribution in the Peruvian populations studied was 47 % C/T, 33 % C/C, and 20 % T/T. The Hardy–Weinberg equilibrium achieved no statistical significance. Conclusions: The 1236T>C polymorphism in the ABCB1 gene among Peruvian populations showed a predominance of the heterozygous C/T genotype, with variations associated with geographic region and altitude. In general, the same trend was observed across countries and continents.

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