The exploration of natural antimicrobial compounds is necessary due to the current bacterial resistance to synthetic antibiotics. For this reason, pineapple residues were evaluated as a natural source of phenolic compounds with antimicrobial capacity. Pineapple residues were fermented with A. niger GH1 and subjected to ultrasound for the extraction of phenolic compounds. In the solid-state fermentation (SSF), the peel and the core (70:30) were fermented for 32 h. Ultrasonic-assisted extraction (UAE) was optimized. The factors solid–liquid ratio (X1), ethanol concentration (X2), and extraction cycle (X3) were optimized through a Box–Behnken statistical design, using the total phenol content (TPC) as a response variable. The optimized and pre-purified extract with amberlite was characterized using HPLC-MS and we measured the antimicrobial activity against Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli. The optimal values for X1, X2, and X3 were 82 mg/mL, 26%, and two cycles, respectively. The extract was effective as an antimicrobial agent against S. aureus and L. monocytogenes, with MICs of 50 mg/mL and 12.5 mg/mL, respectively; the bacterial growth curve and transmission electron microscopy (TEM) confirmed the antimicrobial activity. The main compounds identified in the antimicrobial extract were 3,4-DHPEA-EA, Phloretin 2′-O-xylosyl-glucoside, and Feruloyl tartaric acid. Overall, the combination SSF-UAE showed to be a promising strategy to recover phenolic compounds from pineapple residues, exhibiting great potential as a natural antimicrobial agent.

Background and Aim: The pathogenicity of Escherichia coli is determined by the presence of genes that mediate virulence factors such as adherence capacity and toxin production. This research aimed to identify the adhesion factors and antibiotic resistance capacity of E. coli strains associated with diarrhea in piglets in Colombia. Materials and Methods: Presumptive E. coli strains were isolated from the rectal swabs of piglets in swine farms between 4 and 40 days of age with evidence of diarrhea. Presumptive E. coli strains were tested for antibiotic resistance. The hemolytic capacity of presumptive E. coli strains was measured and molecularly identified. Strains confirmed as hemolytic E. coli was evaluated for the presence of five adhesion factors (F4, F5, F6, F18, and F41) and resistance to 11 antibiotics. Results: Fifty-two putative E. coli strains were isolated, six of which showed a hemolytic capacity. The hemolytic strains were molecularly identified as E. coli. Adhesive fimbriae were found in five of six β-hemolytic E. coli isolates. Combinations of the adhesion factors F6–F18 and F6–F41 were linked to antibiotic resistance capacity. Conclusion: The phenomenon of E. coli strains resistant to multiple antibiotics on pig farms represents a constant risk factor for public health and pig production. Keywords: adhesive fimbriae, piglet diarrhea, enteroaggregative heat-stable toxin 1, enterotoxigenic Escherichia coli, hemolytic capacity.

En este estudio se determinó el efecto de la fuerza iónica y del tiempo de remojo de garbanzo Kabuli (Cicer arietinum L.), frijol cargamanto (Phaseolus vulgaris Cranberry Group), y arveja (Pisum sativum) sobre las cinéticas de absorción de agua y capacidad de retención de agua (CAA y CRA) de cada uno de los granos. Para esto se utilizaron soluciones de 0, 0.1, 2.6, y 5.2 mol de iones de NaCl/L, en relación grano: solución (1:6). En los resultados se encontró que el tipo de grano, la fuerza iónica y el tiempo tuvieron efecto significativo sobre CAA y CRA. En garbanzo con la adición de NaCl a concentración de 0.1M se puede reducir el tiempo de remojo, de 8 h sin sal a 6 h, obteniendo CAA y CRA de 0.8 g y 76.95% respectivamente. En relación con los granos frijol y arveja las mayores CAA Y CRA se obtuvieron con 14h de remojo, sin la adición de NaCl. La adición de NaCl en el remojo de granos puede disminuir el tiempo de remojo, pero la cantidad añadida influye sobre sus propiedades tecnofuncionales.

Background: Antibiotic resistance is a global public health problem. So far, there are limited studies focused on Escherichia coli isolated from pig herds in Colombia. Objective: The objective of this work was to evaluate the resistance to antibiotics of non-pathogenic strains of E. coli isolated from pig farms. Methods: The hemolytic capacity and the presence of thermolabile (LT) and thermostable toxins (STa and STb) were evaluated. Finally, the resistance capacity of the strains to 11 commonly used antibiotics was evaluated in γ - hemolytic strains. Results: A total of 6 E. coli were isolated. The strains presented a high resistance capacity to antibiotics. The highest prevalence of resistance was against Amikacin (20%), Ceftiofur (20%), Fosfomycin (20%), Ciprofloxacin (40%), Gentamicin (40%), Florfenicol (80%), Enrofloxacin Baytril (80%), Norfloxacin (80%), Apramycin (100%), Ampicillin (100%) and Doxycycline (100%). Conclusions: Therefore, commensal strains of E. coli from piglets represent a high epidemiological risk to conserving and disseminating resistance genes in the pig production chain. In addition, these strains have a potential risk of presence in the food chain.