Alfonso García-Galaz

Campylobacter jejuni (C. jejuni) is a leading cause of bacterial gastroenteritis worldwide. Its adherence to host cells decreases when glycoconjugates bear the Fucα1,2-Galβ1,4-GlcNAc epitope, suggesting a lectin-mediated adhesion mechanism. Certain molecular characteristics facilitate the adhesin’s binding to a wide range of glycan ligands, enabling the selection of glycomimetic antagonists. This study tested whether fucoidan, a fucose-containing molecule, could mimic host glycans recognized by C. jejuni and inhibit adhesion to Caco-2 cells. Fucoidan’s glycomimetic potential was evaluated using complex coacervation to form fucoidan–chitosan nanoparticles (F/C-NPs) at the F3:C1 ratio. Infrared spectroscopy confirmed the coacervation of fucoidan with chitosan. The F/C-NPs exhibited a zeta potential of −37.35 ± 0.69 mV, as measured by dynamic light scattering, suggesting the presence of fucoidan on their surface. Their mean size and polydispersity index were 433.95 ± 10.66 nm and 0.15 ± 0.04, respectively. Energy dispersive X-ray spectroscopy detect sulfur from fucoidan’s sulfate groups. ELISA-like lectin assay and confocal microscopy (CM) showed that C. jejuni recognized the F/C-NPs. CM confirmed a ~67% reduction in C. jejuni adhesion to Caco-2 cells in the presence of F/C NPs. These results indicate that F/C NPs could act as glycomimetic antagonists, offering potential for controlling campylobacteriosis.

Fucoidan is a sulfated fucan marine polysaccharide with potential therapeutic applications, including antibacterial activity and the control of virulence factors associated with quorum sensing. This study investigates the bioactivity of fucoidan derived from the brown algae Ascophyllum nodosum, as well as their fucoidan oligosaccharides (OFuc; Campylobacter jejuni, the leading cause of bacterial gastroenteritis worldwide. The results showed that fucoidan decreased the growth rate of C. jejuni at concentrations greater than 25 µg/mL, while no effect was observed with different concentrations (5–100 µg/mL) of OFuc. Neither compound affected bacterial motility. Both fucoidan and OFuc inhibited abiotic biofilm formation and diminished pathogen adhesion in a concentration-dependent manner. The study also found that C. jejuni recognized the fucoidan molecule through an enzyme-like lectin assay (ELLA) showing a lectin-like adhesin-carbohydrate recognition. Overall, these results suggest the potential of fucoidan from A. nodosum for controlling abiotic biofilm formation in the food industry, and they open new avenues for research into the use of fucoidan as a molecule aimed at blocking infections caused by C. jejuni.

Objetivo: analizar la percepción de las madres hermosillenses sobre las prácticas de riesgo sanitario en la alimentación de sus hijos, preescolares y escolares. Metodología: estudio transversal realizado entre 2021 y 2022 en el municipio de Hermosillo, Sonora, México, el cual incluyó entrevistas semiestructuradas. El análisis de los datos se realizó de manera cualitativa, utilizando el análisis de contenido temático. Resultados: las madres perciben que los preescolares tienen mayor vulnerabilidad que los escolares a padecer una infección intestinal. Sin embargo, estos son más enfermizos. Limitaciones: la recolección de los datos se llevó a cabo durante la pandemia de COVID-19, por lo que la interacción con las voluntarias fue virtual. Valor: el estudio aborda los cuidados sobre la salud y la alimentación de los hijos desde una perspectiva materna. Conclusiones: la vigilancia que realizan las madres se acentúa más en los hijos de edad preescolar, con variantes que se relacionan con factores socioculturales, como las creencias, las costumbres familiares, el conocimiento y las experiencias previas.

This research focuses on assessing the synergistic effects of Mexican oregano (Lippia graveolens) essential oil or carvacrol when combined with the antibiotic imipenem, aiming to reduce the pathogenic viability and virulence of Acinetobacter baumannii and Pseudomonas aeruginosa. The study highlighted the synergistic effect of combining L. graveolens essential oil or carvacrol with imipenem, significantly reducing the required doses for inhibiting bacterial growth. The combination treatments drastically lowered the necessary imipenem doses, highlighting a potent enhancement in efficacy against A. baumannii and P. aeruginosa. For example, the minimum inhibitory concentrations (MIC) for the essential oil/imipenem combinations were notably low, at 0.03/0.000023 mg/mL for A. baumannii and 0.0073/0.000023 mg/mL for P. aeruginosa. Similarly, the combinations significantly inhibited biofilm formation at lower concentrations than when the components were used individually, demonstrating the strategic advantage of this approach in combating antibiotic resistance. For OXA-51, imipenem showed a relatively stable interaction during 30 ns of dynamic simulation of their interaction, indicating changes (10 ns, suggesting potential instability. With IMP-1, imipenem also displayed very stable interactions during 38 ns and demonstrated notable movement and positioning changes within the active site, indicating a more dynamic interaction. In contrast, carvacrol and thymol maintained their position within the active site only ~20 and ~15 ns, respectively. These results highlight the effectiveness of combining L. graveolens essential oil and carvacrol with imipenem in tackling the difficult-to-treat pathogens A. baumannii and P. aeruginosa.

Antibiotic resistance is a serious global threat, and the misuse of antibiotics is considered its main cause. It is characterized by the expression of bacterial defense mechanisms, e.g., β-lactamases, expulsion pumps, and biofilm development. Acinetobacter baumannii and Pseudomonas aeruginosa are antibiotic-resistant species that cause high morbidity and mortality. Several alternatives are proposed to defeat antibiotic resistance, including antimicrobial peptides, bacteriophages, and plant compounds. Terpenes from different plant essential oils have proven antimicrobial action against pathogenic bacteria, and evidence is being generated about their effect against antibiotic-resistant species. That is the case for oregano essential oil (Lippia graveolens), whose antibacterial effect is widely attributed to carvacrol, its main component; however, minor constituents could have an important contribution. The analyzed evidence reveals that most antibacterial evaluations have been performed on single species; however, it is necessary to analyze their activity against multispecies systems. Hence, another alternative is using plant compounds to inactivate hydrolytic enzymes and biofilms to potentiate antibiotics’ effects. Despite the promising results of plant terpenes, more extensive and deep mechanistic studies are needed involving antibiotic-resistant multispecies to understand their full potential against this problem.

El género Enterococcus puede ser encontrado en agua, suelo y en general en todo ambiente, son parte de la microbiota intestinal de animales, incluyendo a humanos. La prevalencia en alimentos se debe principalmente a la resistencia que presentan a las condiciones adversas del ambiente. Setenta y tres aislados de vísceras de pollo fueron confirmados como pertenecientes al género a través de pruebas bioquímicas y fermentación de carbohidratos. La caracterización bioquímica indicó que la especie predominante fue E. casseliflavus. La resistencia de los aislados a antimicrobianos fue notoria para amikacina (42 %), kanamicina (38 %), estreptomicina (55 %), and eritromicina (33 %). El análisis obtenido por ERIC-PCR mostró una alta variabilidad genética entre los aislados. Así también, los aislados mostraron relación entre los perfiles obtenidos con la susceptibilidad a antimicrobianos y por ERIC-PCR. Estos resultados muestran la multi-resistencia de Enterococcus en vísceras de pollo expedidos comercialmente, con una alta variabilidad genética. Además, estos Enterococcus pueden ser potencialmente patógenos en individuos como una bacteria nosocomial y además transferir la resistencia en especies que son estrictamente patógenas y causan enfermedades al humano.