Andrés Sandoval Lozano

"Enfermedades Infecciosas Tropicales en Cuidado Crítico es una obra académica de carácter científico y médico que aborda, desde una perspectiva multidisciplinaria, clínica y basada en la evidencia, las principales enfermedades infecciosas de importancia en las regiones tropicales, con especial énfasis en su diagnóstico, tratamiento y manejo integral en los servicios de urgencias y las unidades de cuidado crítico. La publicación responde a la necesidad de fortalecer las competencias del personal de salud para la identificación temprana de enfermedades potencialmente graves, la toma de decisiones clínicas oportunas y la atención segura y de calidad de los pacientes. La obra está organizada en diecisiete capítulos que desarrollan aspectos fundamentales de la respuesta inmunológica, la interpretación del laboratorio clínico, las enfermedades infecciosas emergentes y reemergentes y el enfoque diagnóstico del paciente procedente o residente de zonas tropicales. Asimismo, profundiza en patologías de especial relevancia epidemiológica y clínica, entre ellas la fiebre amarilla, la malaria, el dengue, el chikungunya, el Zika, la varicela, el tétanos, la leptospirosis, la rabia humana, la meningitis bacteriana, las encefalitis virales, el cólera y la fiebre tifoidea. Cada capítulo aborda elementos esenciales para la comprensión y el abordaje clínico de estas enfermedades, incluyendo definiciones, epidemiología, fisiopatología, clasificación, manifestaciones clínicas, diagnóstico diferencial, pruebas complementarias y principios terapéuticos, con especial atención al reconocimiento de signos de gravedad, las complicaciones sistémicas y los criterios que orientan la atención en cuidado crítico. Dirigida a médicos generales y especialistas, profesionales de urgencias y cuidado intensivo, docentes, investigadores, residentes y estudiantes de ciencias de la salud, esta publicación constituye un recurso de consulta y formación para la práctica clínica, la docencia y la investigación. Su contenido contribuye a la difusión del conocimiento científico sobre las enfermedades infecciosas tropicales y al fortalecimiento de las capacidades de respuesta del talento humano en salud, particularmente en Colombia y en la región surcolombiana. La obra, publicada por la Editorial UNINAVARRA en 2026, representa además un aporte académico al desarrollo del conocimiento médico desde las regiones y constituye un homenaje póstumo al legado científico, docente y asistencial del doctor Abner Lozano Losada, editor emérito de la publicación."

During the fermentation of cacao beans, a succession of microorganisms, including yeasts, lactic acid bacteria, acetic acid bacteria, and Bacillus, are involved in the generation of aroma and flavor precursors. These microbial consortia have been extensively studied, except for the genus Bacillus . Accordingly, this work aimed to isolate and select Bacillus isolates and evaluate their effect on the fermentation process of CCN51 genotype cacao beans. The isolates were obtained from a fermentation process using native cacao material. The isolates were selected based on growth performance and biological activity assays, including the production of pectinases, proteases, citrate lyases, and antifungal activity. Subsequently, their effect as a starter culture on the CCN51 genotype beans was evaluated. The isolates were individually evaluated at a concentration of 7 × 10 ⁶ CFU/mL in a proportion of 1% starter culture (v/w) relative to the cacao mass. Temperature, pH, acidity, fermentation index, and cut test were monitored, showing higher fermentation index values (up to 1.5) and a reduction of insufficiently fermented beans (from 36% in the control to 13–20%) in inoculated treatments. The evaluation of the effect of Bacillus isolate on cacao fermentation indicated that the B. megaterium isolate improved the sensorial quality of cacao beans, decreased their bitterness and astringency, and highlighted flavors such as floral, fruity, nutty, and cane sugar-malt. It also registered antifungal activity against mycotoxin-producing fungi. It can be concluded that Bacillus has biotechnological potential as a producer of enzymes of interest for cacao processing and the food industry.

Despite the recognized benefits of endophytic entomopathogenic fungi (EEPF) as biological control agents, their potential role in promoting plant growth and inducing systemic resistance (ISR) in olive nurseries remains poorly understood. Many fungi live in close association with plants, and a deeper understanding of the interactions among beneficial fungi is required to unravel the complex relationships among olive cultivars and phytopathogens, which can be fundamental for improving crop production and protection. EEPF are important soil-inhabiting microorganisms that can provide several benefits to olive plants beyond insect pest control. This study investigates the role of Metarhizium brunneum in the olive rhizosphere during the nursery stage, focusing on its potential to promote plant growth and induce systemic resistance in Picual and Manzanilla cultivars. Conidia and microsclerotia of the M. brunneum EAMa 01/58-Su strain, together with an arbuscular mycorrhizal fungus (AMF), were applied to olive plants. Fungal colonization, growth promotion, and induction of systemic resistance were evaluated. Microbiological, qPCR, and droplet digital PCR analyses showed that M. brunneum colonized roots via the apoplastic pathway when applied as conidia or microsclerotia. Mycorrhization rates were higher in Manzanilla, but elevated mycorrhization inhibited M. brunneum colonization. Growth-promoting effects were more pronounced in Picual. Application of the EAMa 01/58-Su strain induced specific subsets of systemic resistance (SR) genes associated with the ISR pathway. Additionally, Picual plants treated with both AMF and microsclerotia exhibited increased leaf nitrogen and potassium levels. Overall, this strain demonstrates promising potential as a plant growth promoter during the early nursery stage of olive cultivation. IMPORTANCE: Olive cultivation is an economically and culturally significant crop; however, early-stage plant growth in nurseries can be limited by nutrient uptake, abiotic stress, and pathogen pressure. Endophytic entomopathogenic fungi (EEPF), such as Metarhizium brunneum , are traditionally used for biological control of insect pests, but their potential to promote plant growth and induce systemic resistance has been overlooked and is currently of interest to olive nursery companies. This study demonstrates that M. brunneum EAMa 01/58-Su can effectively colonize olive roots, improve certain vegetative growth parameters, and activate systemic resistance pathways, influenced by both cultivar and the application with arbuscular mycorrhizal fungi prior to field transplantation. These findings highlight the dual role of the M. brunneum EAMa 01/58-Su strain in olive nurseries, providing both pest protection and growth-promoting benefits. Integrating EEPF into nursery management could enhance plant health, nutrient status, and stress resilience, offering a sustainable strategy for early-stage cultivation and contributing to more productive and resilient olive orchards.

Small ruminant production is increasingly affected by heat stress, with recent heat waves highlighting growing economic and welfare-related challenges. Chronic exposure to elevated temperatures disrupts thermoregulation, reduces feed intake, slows growth, compromises meat quality, and increases mortality. This study evaluated the effects of chromium-yeast supplementation at different doses and timepoints on physiological and molecular stress biomarkers in heat-stressed lambs. Forty-eight clinically healthy 6-month-old Katahdin lambs (average weight 20 ± 2.9 kg) were assigned to a 2 × 4 factorial design, with two ambient temperature conditions (heat stress [HS] and thermoneutral [TN]) and four levels of dietary Cr-yeast (0, 0.2, 0.4, and 0.8 mg/kg of dry matter intake). Lambs were housed individually in pens (1.2 × 2.5 m), with ad libitum access to water, and fed a 50:50 corn silage and concentrate diet (excluding mineral premix) twice daily. Blood samples were collected at days 0, 30, and 60 to evaluate plasma cortisol and the expression of hsp60 and hsp70. Chromium bioavailability was assessed by blood levels using absorption chromatography, and glucose clearance was measured at the end of the experiment. Significant reductions in cortisol and hsp70 expression were observed after 30 days of Cr-yeast supplementation under HS conditions (p < 0.05), particularly at the highest dose. For hsp60, a significant reduction was observed at the highest dose on day 30 under HS (p < 0.05). These effects were not sustained on day 60 (p > 0.05). No significant differences were detected under TN conditions (p > 0.05). These findings suggest that Cr-yeast may offer short-term physiological and cellular protection against chronic heat stress in lambs.

The aim of this study was to evaluate and select entomopathogenic fungi that produces insecticidal compounds for the control of adults of Anastrepha obliqua Macquart (Diptera: tephritidae) that are the main pest of mango (Mangifera indica L. Bark) in Colombia. Nine entomopathogenic fungi isolates were evaluated, five belonging to the genus Metarhizium and four belonging to the genus Beauveria. One strain of the species Metarhizium robertsii with insecticidal activity was selected. By column fractionation, an active fraction was obtained, which caused mortalities higher than 90% after 48 h of exposure. Through HPLC it was determined that the active fraction is composed of more than 22 metabolites. Identification of the metabolites by UHPLC MS/MS revealed the presence of destruxin in E, D, A and B groups (destruxin E-diol, destruxin D, destruxin D1, destruxin D2, destruxin A2, destruxin A, destruxin A3, dihydrodestruxin A, desmB, destruxin B2, destruxin B and destruxin B1). The evaluation of the insecticidal capacity of the organic fractions obtained by HPLC indicated that the extract obtained from the isolate M. robertsii had a compound with high activity on adults of A. obliqua (destruxin A) causing massive mortality of up to 100%, after 48 h of the treatment administration. Furthermore, two other compounds with medium activity were found (destruxin A2 and destruxin B), showing mortalities between 60.0 and 81.3%, respectively. The extract of the isolate MT008 of M. robertsii showed higher insecticidal activity and a potential source for the control of A. obliqua