The synthesis, characterization and antimicrobial activity of novel vanadium (IV) complex derived of amide natural piplartine is reported. The minimum inhibitory concentrations (MIC) of complex, piplartine and vanadyl sulphate used in the synthesis were determined against six bacteria and one fungus. The complex exhibited good activity with minimal inhibitory concentration values ranging from 156.2 to 625 µg mL-1, it was observed the lowest value for the Escherichia coli bacteria with MIC 156.2 µg mL-1 and Microsporum gypseum fungus with MIC 312.5 µg/mL. In overall, the complex showed better antimicrobial activity than the piplartine. Additionally, the V-PIP complex was completely soluble in water, on the contrary of the piplartine free; which means that the proposal complex consists in a potential candidate to drug.

The selection of new microorganisms able to produce antimicrobial compounds is hoped for to reduce their production costs and the side effects caused by synthetic drugs. Clavulanic acid is a β-lactam antibiotic produced by submerged culture, which is widely used in medicine as a powerful inhibitor of β-lactamases, enzymes produced by bacteria resistant to antibiotics such penicillin and cephalosporin. The purpose of this work was to select the best clavulanic acid producer among strains of Streptomyces belonging to the Microorganism Collection of the Department of Antibiotics of the Federal University of Pernambuco (DAUFPE). Initially, the strains were studied for their capacity to inhibit the action of β-lactamases produced by Klebsiella aerogenes ATCC 15380. From these results, five strains were selected to investigate the batch kinetics of growth and clavulanic acid production in submerged culture carried out in flasks. The results were compared with the ones obtained by Streptomyces clavuligerus ATCC 27064 selected as a control strain. The best clavulanic acid producer was Streptomyces DAUFPE 3060, molecularly identified as Streptomyces variabilis, which increased the clavulanic acid production by 28% compared to the control strain. This work contributes to the enlargement of knowledge on new Streptomyces wild strains able to produce clavulanic acid by submerged culture.

Embora existam linhagens de Escherichia coli não patogênicas para aves, muitas outras possuem a capacidade de causar sérios danos à saúde das mesmas, sendo capazes de ocasionar diferentes tipos de processos infecciosos. As linhagens patogênicas são denominadas Avian Pathogenic Escherichia coli (APEC), possuindo genes relacionados ao processo de patogênese em epissomos (plasmídios) ou no cromossomo. A presença de plasmídios, contendo genes de resistência a antibióticos em linhagens aviárias, patogênicas ou não, indicam a possibilidade de transferência gênica lateral entre diferentes tipos de linhagens facilitando também a transferência de genes de patogenicidade ou virulência. Objetivou-se com este estudo avaliar o perfil de sensibilidade a antibióticos (13) de diferentes amostras (35) de E. coli isoladas de aves comerciais do Estado de Pernambuco apresentando, ou não, sinais clínicos de processos infecciosos e correlacionar esta resistência com a presença de plasmídios. Os testes utilizados demonstraram que 94,28% dos isolados foram resistentes a três ou mais antibióticos, com a lincomicina apresentando o maior percentual de resistência (100%). Na Concentração Inibitória Mínima (CIM) observou-se multirresistência a vários antimicrobianos. A presença de plasmídios foi detecada em 80,0% (28/35) dos isolados, com 16 isolados apresentando plasmídios com peso molecular aproximado de 88 MDa. Também foi verificada a presença de linhagens apresentando plasmídios de vários tamanhos. Concluiu-se que isolados de E. coli resistentes a antimicrobianos utilizados na avicultura estão presentes no Estado de Pernambuco, tanto em frangos de corte quanto em poedeiras comerciais. A presença de plasmídios detectados na maioria dos isolados pode estar associada à resistência aos antimicrobianos e sugere a presença de possíveis genes relacionados à patogenicidade. Monitorar a resistência a antibióticos em bactérias isoladas de animais torna-se um fator determinante para eleição e êxito do tratamento, bem como a possibilidade de eliminação daquelas que possuem plasmídios para se evitar a transferência de genes relacionados à patogenicidade.

Although exist poultry non-pathogenic Escherichia coli strains, many others have capacity to impose serious damages to this birds, being able to cause different infectious diseases. Pathogenic strains are termed Avian pathogenic Escherichia coli (APEC) strains. APEC strains harbor chromossomal and plasmid pathogenicity-related genes. The presence of resistance plasmids in avian E. coli strains could facilitate horizontal tranfer of virulence gene between pathogenic and non pathogenic strains. The aim of this paper was to determine the resistance level to 13 different antibacterial drugs of avian E. coli strains (35) isolated from commercial poultry of Pernambuco State, Brazil, and to correlate the detected resistance level to the presence of plasmids. The results show that 94.28% of strains were resistant to at least three different antibacterial drugs with the highest percentage to lincomycin. The Minimal Inibitory Concentration (MIC) showed that multi- resistance to various antibacterial drugs was present in these strains. Plasmids of several sizes, including plasmids of approximately 88Mda were detected in most of the studied strains. The results herein obtained suggest that the high resistance level observed could be due to the presence of plasmids, what could facilitate the transfer of pathogenicity related genes among pathogenic and non pathogenic strains; it is necessary to take a constant survey on the resistance level to antimicrobial drugs of avian E. coli strains to reach a better control of APEC strains and avoid transfer of pathogenicity related genes between strains.

Clavulanic acid is a β-lactam antibiotic which has a potent β-lactamase inhibiting activity. In order to optimize its production by the new isolate Streptomyces DAUFPE 3060, the influence of two independent variables, temperature and soybean flour concentration, on clavulanic acid and biomass concentrations was investigated in 250 mL-Erlenmeyers according to a 2² central composite design. To this purpose, temperature and soybean flour (SF) concentration were varied in the ranges 26-34°C and 10-50 g/L, respectively, and the results evaluated utilizing the Response Surface Methodology. The experimental maximum production of clavulanic acid (629 mg/L) was obtained at 32°C and 40 g/L SF after 48 h, while the maximum biomass concentration (3.9 g/L) at 30°C and 50 g/L soybean flour, respectively. These values are satisfactorily close to those (640 mg/L and 3.75 g/L, respectively) predicted by the model, thereby demonstrating the validity of the mathematical approach adopted in this study.

Microrganismos endofíticos são frequentemente encontrados no interior de plantas cultivadas. Embora vários tipos de microrganismos endofíticos tenham sido isolados de milho (Zea mays) não existiam dados sobre certos grupos de actinomicetos obtidos a partir desta espécie de planta cultivada. No presente trabalho, actinomicetos endofíticos foram isolados de folhas e raízes de milho. Um total de 53 isolados foram obtidos sendo 31 deles a partir de folhas e 22 a partir de raízes. O gênero Microbispora foi o mais frequente (62%), seguido dos gêneros Streptomyces e Streptosporangium. Dos actinomicetos isolados, 43,4% apresentaram atividade antimicrobiana contra um ou mais microrganismos ensaiado.

Actinomycetes were isolated from surface sterilized leaves and roots of maize. A total of 53 isolates were obtained, 31 of them from leaves and 22 from roots. The genus Microbispora was the most frequently found followed by the genera Streptomyces and Streptosporangium. From the isolated actinomycetes, 43.4% showed antimicrobial activity against one or more tested bacteria and yeast.