Érima Jôyssielly Mendonça Castro

The growing threat of antimicrobial resistance has intensified the search for new antimicrobial materials. In this work, zinc bismuthate-based nanocomposites (ZB1 and ZB4) were synthesized by a hydrothermal method and characterized using X-ray diffraction, Raman spectroscopy, zeta potential and high-resolution transmission electron microscopy. Structural analyses suggested the coexistence of a zinc oxide secondary phase and oxygen vacancies, which may influence the physicochemical and biological behavior of the materials. The antimicrobial activity was evaluated against Staphylococcus aureus, Corynebacterium diphtheriae, Klebsiella pneumoniae, Cryptococcus neoformans, and Candida albicans by disk diffusion. For C. diphtheriae and C. neoformans, additional minimum inhibitory concentration and minimum fungicidal concentration assays were performed. Both nanocomposites inhibited S. aureus, C. diphtheriae, and C. neoformans, while no inhibition was observed for C. albicans and K. pneumoniae. ZB4 exhibited superior antimicrobial activity, with growth inhibition observed up to 500 µg mL-1, whereas ZB1 was effective only at higher concentrations. Toxicity tests using Tenebrio molitor larvae revealed survival rates of approximately 70% for ZB1 and 60% for ZB4 after 10 days, with no statistically significant difference compared to the control. Overall, ZB4 presented promising antimicrobial activity with moderate toxicity, indicating its potential for biomedical applications.

Background/Objectives: The growing threat of antimicrobial resistance (AMR) has inten-sified the search for innovative antimicrobial materials. Herein, we synthesized and characterized zinc bismuthate-based nanocomposites (ZB1 and ZB4) and investigated their antimicrobial efficacy against two Gram-positive bacteria (Staphylococcus aureus and Corynebacterium diphtheriae), one Gram-negative bacterium (Klebsiella pneumoniae), and two fungal pathogens (Cryptococcus neoformans and Candida albicans). Toxicity was further as-sessed using Tenebrio molitor larvae as an alternative model. Methods: Nanocomposites were prepared via a hydrothermal process and characterized using X-ray diffraction (XRD), Raman spectroscopy, Zeta potential, and high-resolution transmission electron microscopy (HR-TEM). Antimicrobial activity was evaluated through disk diffusion as-says coupled with minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) assessments. Results: ZB1 and ZB4 inhibited S. aureus (10.7 ± 1.2 mm and 11.3 ± 1.2 mm), C. diphtheriae (10.7 ± 1.1 mm and 11.3 ± 1.1 mm), and C. neoformans (10.7 ± 1.1 mm and 11.7 ± 2.9 mm), while no inhibition was observed for C. albicans and K. pneumoniae. From MIC and MFC evaluations, ZB1 was effective up to 1000 μg/mL, and ZB4 up to 500 μg/mL. Toxicity assays revealed survival rates of 70% for ZB1 and 60% for ZB4, with no statistically significant differences compared to the control (p = 0.156). Notably, ZB4 is a promising candidate due to its enhanced antimicrobial performance and moderate toxicity. Conclusions: Our findings highlight ZB1 and ZB4 nanocomposites as promising antimicrobial agents, offering new avenues in nanotechnology-driven healthcare solutions aimed at tackling antimicrobial resistance.

O manguezal é um ecossistema de transição terrestre-marinho, rico e propício ao desenvolvimento de diversos seres vivos interessantes no contexto biotecnológico. Tendo em vista a busca por compostos bioativos com propriedades antifúngicas, esta pesquisa teve como objetivo o escalonamento microbiano de isolado de mangue com atividade frente a patógenos agrícolas, em meio de baixo custo. Para avaliação da atividade antifúngica foram utilizados cinco fitopatógenos: Fusarium solani (Fp1), Fusarium oxysporum (Fp2), Macrophomina phaseolina (Fp3), Rhizoctonia solani (Fp4), e Sclerotium rolfsii (Fp5). O processo foi realizado utilizando Caldo Natural Batata Dextrose, feito para 50ml, 100ml e 250ml, aproveitando a casca da batata que permitiu o crescimento da bactéria e secreção dos metabólitos secundários para o meio externo, possibilitando a realização do teste difusão em ágar frente aos patógenos agrícolas. Com o escalonamento observou-se que os microrganismos se mantiveram estáveis em todos os volumes utilizados no processo. Após isolamento microbiano de sedimento de manguezal a identificação microbiana e molecular, obteve-se a bactéria Serratia Marcescens, uma bactéria gram-negativa. Cultivada comumente em meio clássico para crescimento universal, Mueller Hinton (MH) e meio diferencial macConkey. No entanto, o meio natural proporcionou um aumento desejável no crescimento das colônias de diversos grupos microbianos, pois é rico em açucares. A bactéria isolada apresentou performance promissora com potencial biocontrolador, visto que, apresentou atividade antifúngica, evidenciada pela formação de halos, para os cincos patógenos agrícolas testados. Portanto, podemos inferir que o processo a utilização de meio de baixo custo estimula e viabiliza o crescimento e a avaliação da atividade microbiana.

This study analyzed the antifungal potential of 16 bacterial strains isolated from mangrove sediment. Bacterial selection was conducted in a solid medium. This was followed by the production and extraction of metabolites using ethyl acetate to evaluate chitinase production, antifungal activity, and toxicity toward Allium cepa and Tenebrio molitor. Bacterial strains B8, B11, and B13 produced the largest inhibition halos (>30 mm) toward Fusarium solani, Fusarium oxysporum, and Rhizoctonia solani fungi. Strains B1, B3, B6, B8, B11, B13, B14, and B16 produced chitinases. In assays using liquid media, B8 and B13 produced the largest inhibition halos. Exposing the fungal inocula to metabolic extracts of strains B6, B8, B11, B13, B14, B15, and B16 caused micromorphological alterations in the inocula, culminating in the inhibition of R. solani sporulation and spore germination. Toxicity tests using Allium cepa and Tenebrio molitor revealed that the metabolites showed low toxicity. Six of the bacterial strains were molecularly identified to species levels, and a further two to genus level. These included Serratia marcescens (B8), which exhibited activity in all tests. Mangroves provide a useful resource for the isolation of microorganisms for biocontrol. Among the isolates, Serratia marcescens and Bacillus spp. showed the greatest potential to produce metabolites for use as biocontrol agents in agriculture.

Healthcare-related infections caused by resistant microorganisms are a severe public health problem and are becoming increasingly prevalent in the hospital environment, especially Pseudomonas aeruginosa. This work aimed to evaluate the resistance profile of Pseudomonas aeruginosa to antimicrobials before the COVID-19 pandemic and during the pandemic period. Bacteria strains were obtained from tracheal aspiration, sputum, and bronchoalveolar lavage for diagnosis and phenotypic characterization. Matrix assisted laser-desorption ionization-time of flight mass spectrometry (MALD-TOF MS) was used to identify strains. Automated Phoenix and VITEK^® 2 Compact system and the disc diffusion method were performed to determine the antimicrobial susceptibility profile. A total of 41,000 medical reports from adult patients with pneumonia were analyzed. Of these, 951 patients were positive for P. aeruginosa, of which 373 were related to the pre-pandemic period and 578 to the pandemic period. Older men (≥60 years) were more prevalent in both periods. P. aeruginosa strains were resistant to imipenem in both periods: 38.8 and 42.5%, respectively, followed by meropenem (34.2 and 39.2%), ciprofloxacin (33.6 and 36.7%), and levofloxacin (34.9 and 43.5%). Intensive care units had the highest percentage of affected patients (62 and 65%) compared with other sectors, with a prevalence of 71% in the public network before COVID-19 and 59% during the pandemic. Our data showed a prevalence of P. aeruginosa in elderly patients in both the pre-pandemic and pandemic periods. In addition, an increase in P. aeruginosa resistance to beta-lactams, quinolones, carbapenems, and cephalosporins was observed during the COVID-19 pandemic compared with the period before the pandemic, especially in ICUs.

Temas de grande importância, como a tuberculose, são plausíveis de abordagem dentro da comunidade escolar, visto que, é uma doença com grande ocorrência e relevância. O objetivo do projeto foi promover o conhecimento da comunidade escolar acerca da importância da tuberculose, assegurando a disseminação de informações ao público-alvo. O projeto foi realizado na Escola Caminho das Estrelas, situada dentro do Centro de Lançamento do Município de Alcântara – Maranhão. A unidade de ensino contempla o ensino fundamental para 132 crianças do 1º ao 9º ano. Todos os alunos foram pré-avaliados para que fossem mensurados seus conhecimentos acerca da tuberculose. Em seguida, a temática foi explorada através de uma peça teatral com a presença dos membros executores do projeto, onde foram contemplados conceitos, sintomatologia, diagnóstico e tratamento da doença. Posteriormente, os alunos foram novamente avaliados, para assim, medir-se o aprendizado e desempenho dos alunos frente à ação proposta. Foi possível concluir através da intervenção, os escolares (1º ao 9º ano) tem pouco conhecimento sobre microbiologia, além disso, 36 (60%) das crianças do grupo 1 nunca tinham ouvido falar sobre tuberculose e 48 (80%) não sabiam sobre a cicatriz vacinal da BCG. O grupo 2, 4,33% acreditam que o tratamento da tuberculose é realizado através de chás ou de cirurgia. Por isso, se faz necessárias intervenções para que as crianças e adolescentes saibam o máximo de informações sobre a tuberculose, assegurando a disseminação de informações por elas para a comunidade em geral a sua volta.

Análise dos padrões dos focos de queimadas por biomas do estado do Maranhão/ Analysis of the patterns of fires in biomes in the state of Maranhão

Qualis indexed Engineering Journal and Science Journal to publish paper with DOI, NAAS Rating and journal has global recognized indexing

Uso de experimentos de modelagem espacial para aferição dos impactos da elevação do mar no meio urbano / Use of spatial modeling experiments to measure the impacts of sea elevation in urban areas