The increasing prevalence of multi-drug resistant (MDR) Escherichia coli in distinct ecological niches, comprising water sources and food-producing animals, such as fish species, has been widely reported. In the present study, quinolone-resistant E. coli isolates from Arapirama gigas, a major fish species in the Brazilian Amazon rivers and fish farms, were characterized regarding their antimicrobial susceptibility, virulence, and genetic diversity. A total of forty (40) specimens of A. gigas, including 20 farmed and 20 wild fish, were included. Thirty-four quinolone-resistant E. coli isolates were phenotypically tested by broth microdilution, while resistance and virulence genes were detected by PCR. Molecular epidemiology and genetic relatedness were analyzed by MLST and PFGE typing. The majority of isolates were classified as MDR and detected harboring bla_CTX-M, qnrA and qnrB genes. Enterotoxigenic E. coli pathotype (ETEC) isolates were presented in low prevalence among farmed animals. MLST and PFGE genotyping revealed a wide genetic background, including the detection of internationally spread clones. The obtained data point out A. gigas as a reservoir in Brazilian Amazon aquatic ecosystems and warns of the interference of AMR strains in wildlife and environmental matrices.

Staphylococcus aureus is a microorganism with high morbidity and mortality due to antibiotic-resistant strains, making the search for new therapeutic options urgent. In this context, computational drug design can facilitate the drug discovery process, optimizing time and resources. In this work, computational methods involving ligand- and structure-based virtual screening were employed to identify potential antibacterial agents against the S. aureus MRSA and VRSA strains. To achieve this goal, tetrahydroxybenzofuran, a promising antibacterial agent according to in vitro tests described in the literature, was adopted as the pivotal molecule and derivative molecules were considered to generate a pharmacophore model, which was used to perform virtual screening on the Pharmit platform. Through this result, twenty-four molecules were selected from the MolPort^® database. Using the Tanimoto Index on the BindingDB web server, it was possible to select eighteen molecules with greater structural similarity in relation to commercial antibiotics (methicillin and oxacillin). Predictions of toxicological and pharmacokinetic properties (ADME/Tox) using the eighteen most similar molecules, showed that only three exhibited desired properties (LB255, LB320 and LB415). In the molecular docking study, the promising molecules LB255, LB320 and LB415 showed significant values in both molecular targets. LB320 presented better binding affinity to MRSA (−8.18 kcal/mol) and VRSA (−8.01 kcal/mol) targets. Through PASS web server, the three molecules, specially LB320, showed potential for antibacterial activity. Synthetic accessibility (SA) analysis performed on AMBIT and SwissADME web servers showed that LB255 and LB415 can be considered difficult to synthesize and LB320 is considered easy. In conclusion, the results suggest that these ligands, particularly LB320, may bind strongly to the studied targets and may have appropriate ADME/Tox properties in experimental studies.

Two heteroaromatic hybrid compounds were synthesized and characterized using various analytical techniques. The results indicate that the benzimidazole/oxadiazole (BZ/OZ) metal derivative exhibits a tridentate coordination mode, where the carbonyl, imidazole and oxadiazole groups participate in coordination with the metal, in a ratio of 2:1 of the ligand to the metal. The antibacterial activities of the organic ligand and its metal complex were determined by in vitro tests against both Gram-positive bacterial strains and Gram-negative bacterial strains using the broth microdilution method. The metal complex showed greater antibacterial activities compared to the precursor ligand against all evaluated microorganisms. The results obtained through in silico predictions revealed significant toxicological differences among the analyzed molecules, suggesting special attention in the use of the ligand due to its possible carcinogenicity in mice and a need for structural modifications in the complex to reduce its carcinogenicity and toxicity. Furthermore, a biophysical study of the interaction of the BZ/OZ derivatives with different model membranes was explored through differential scanning calorimetry (DSC), simultaneous small- and wide-angle X-ray diffraction (SAXD and WAXD) and infrared spectroscopy (FT-IR). The results indicate that the compounds influenced membrane properties without significantly altering the lamellar organization. The findings suggest potential applications in understanding lipid interactions, elucidating toxicology and developing antibacterial agents.

The objective of this work was to analyze the contamination by iron (Fe) and zinc (Zn) in the shrimp Macrobrachcium amazonicum in the region of the mouth of the Amazon River in the State of Amapá, taking into account aquaculture and fishing activities. 90 shrimp were used, 45 females and 45 males of M. amazonicum. The animals (30) were found in three different points, being Mazagão Velho in Mazagão, a community on Ilha de Santana, a district in the Brazilian municipality of Santana and Arquipélago do Bailique. Fe and Zn determinations were performed by conventional flame atomic absorption spectrophotometry. The greatest accumulation of Zn in the organs and the lowest concentration of Zn in the muscle and exoskeleton of M. amazonicum was observed. Fe had the highest accumulation in organs, followed by exoskeleton and muscle. Zn accumulation in male organs was greater than in muscle and exoskeleton while Fe concentrations were greater in organs, followed by exoskeleton and muscle. In females, Zn accumulation was greater in our organs, with no difference between muscle and exoskeleton. According to the present study, to maintain levels of food security, the consumption of freshwater shrimp caught and farmed in Mazagão, Bailique Archipelago and community of Ilha de Santana should be limited to a daily shrimp intake dose of 96. 52 g for Fe and 226.81 g for Zn.

Antibiotic resistance among several bacteria is a warning sign that reinforces the need for research to identify new compounds that are effective against resistant strains. In this sense, bioinformatics stands out as an excellent tool for identifying drug candidates by using computational methodologies to detect compounds with potential biological activity. Two pivot compounds (QNZ and 0Y5) with biological activity against Staphylococcus aureus were selected. A virtual screening was performed in the MolPort database with a Tanimoto index of 0.5, resulting in 20,000 compounds, 10,000 compounds for each template. Then, methodologies were applied to calculate pharmacokinetic and toxicological parameters using Discovery Studio software; molecular docking via DockThor; lethal dose via ProTOX; lipophilicity, solubility, and Lipinski parameters via SwissADME; in silico prediction of bacterial activity via Way2Drug; theoretical synthetic accessibility via SwissADME and AMBIT-SA; and, finally, molecular dynamics simulations via AMBER 18. After the entire methodological process, 10 compounds were identified with potential results according to the criteria adopted in this study and with possible antimicrobial activity against resistant bacterial strains of S. aureus. Our theoretical findings suggest 10 potential candidates with possible antimicrobial activity against S. aureus and other genera and species of bacteria as these compounds presented excellent results using the proposed methodology. Certainly, more in vitro and in vivo study steps are necessary.

Aeromonas spp. são bactéria Gram-negativa que apresentam características como a forma de bastonete, sendo considerada patogênica para os animais em ambientes aquáticos causando infecções e doenças, e ocasionalmente em humanos, especialmente em indivíduos imunocomprometidos. De forma análoga, essas bactérias podem invadir, fixa e danificar células hospedeiras, além de contaminar alimentos e a própria água corroborando para sua virulência e incidência. O objetivo do presente artigo é discorrer sobre a incidência da bactéria do gênero Aeromonas spp. em água, animais aquáticos e alimentos. Foi realizado um levantamento bibliográfico em bases de dados como PuBmed e Sieclo, com artigos dos anos de 2019 a 2025, utilizando o método PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses). Como Resultado, a Aeromonas spp. apresentam diversos fatores de disseminação, como, contaminação da água, vazamento de esgoto, uso indiscriminados de antimicrobianos, falta de higiene nos produtos manipulados e a presença de genes como elastase, hemolisinas, aerolisinas, adesinas, enterotoxinas, fosfolipases e lipases, que levam a atividades patogênicas dessas bactérias para outros animais aquáticos. Outrossim, essa bactéria é também encontrada em água potável e alimentos como leite, peixe, carne, camarão vegetais frescos e outros, o que pode causar doenças para e infecções para os seres humanos e para saúde dos animais aquáticos. Destarte, a presença de Aeromonas spp. representa uma ameaça potencial à saúde pública, pois os fatores de disseminação corroboram para seu crescimento.